tape: Fix crash when decoding a bool sometimes

Reviewed-on: #21

.gitignore

@@ -0,0 +1,2 @@
+/generate/test
+/debug

cmd/hopp-generate/main.go

@@ -1,43 +1,66 @@
 package main
 
 import "os"
-import "fmt"
 import "strings"
 import "path/filepath"
+import "git.tebibyte.media/sashakoshka/go-cli"
+import "git.tebibyte.media/sashakoshka/goparse"
 import "git.tebibyte.media/sashakoshka/hopp/generate"
 
 func main() {
-	name := os.Args[0]
-	if len(os.Args) != 3 {
-		fmt.Fprintf(os.Stderr, "Usage: %s SOURCE DESTINATION\n", name)
+	flagOutput      := cli.NewInputFlag('o', "output", "The output file", "", cli.ValString)
+	flagPackageName := cli.NewInputFlag('p', "package-name", "The package name of the file", "", cli.ValString)
+	command := cli.New("Compile PDL files to program source code",
+		flagOutput,
+		flagPackageName)
+	command.Syntax = "FILE [OPTIONS]..."
+	command.ParseOrExit(os.Args)
+
+	if len(command.Args) != 1 {
+		command.Usage()
 		os.Exit(2)
 	}
-	source      := os.Args[1]
-	destination := os.Args[2]
+	source      := command.Args[0]
+	destination := flagOutput.Value
+	if destination == "" {
+		destination = "protocol.go"
+	}
 
 	input, err := os.Open(source)
-	handleErr(1, err)
+	handleErr(command, 1, err)
 	defer input.Close()
-	protocol, err := generate.ParseReader(input)
-	handleErr(1, err)
+	protocol, err := generate.ParseReader(source, input)
+	handleErr(command, 1, err)
 
+	packageName := flagPackageName.Value
+	if packageName == "" {
 		absDestination, err := filepath.Abs(destination)
-	handleErr(1, err)
-	packageName := cleanPackageName(strings.ReplaceAll(
-		strings.ToLower(filepath.Base(absDestination)),
-		" ", "_"))
-	destination = filepath.Join(os.Args[2], "generated.go")
+		handleErr(command, 1, err)
+		base := filepath.Base(absDestination)
+		if scrounged, ok := scroungeForPackageName(base); ok {
+			packageName = scrounged
+		} else {
+			packageName = strings.ReplaceAll(
+				strings.ToLower(base),
+				" ", "_")
+		}
+	}
+	packageName = cleanPackageName(packageName)
 
 	output, err := os.Create(destination)
-	handleErr(1, err)
-	err = protocol.Generate(output, packageName)
-	handleErr(1, err)
-	fmt.Fprintf(os.Stderr, "%s: OK\n", name)
+	handleErr(command, 1, err)
+	generator := generate.Generator {
+		Output:      output,
+		PackageName: packageName,
+	}
+	_, err = generator.Generate(protocol)
+	handleErr(command, 1, err)
+	command.Println(output, "OK")
 }
 
-func handleErr(code int, err error) {
+func handleErr(command *cli.Cli, code int, err error) {
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		command.Errorln(parse.Format(err))
 		os.Exit(code)
 	}
 }
@@ -56,3 +79,32 @@ func cleanPackageName(str string) string {
 	}
 	return string(buffer[:j])
 }
+
+func scroungeForPackageName(dir string) (string, bool) {
+	entries, err := os.ReadDir(dir)
+	if err != nil { return "", false}
+	for _, entry := range entries {
+		if !entry.Type().IsRegular() { continue }
+		file, err := os.Open(filepath.Join(dir, entry.Name()))
+		if err != nil { continue }
+		defer file.Close()
+		// FIXME: it is entirely possible that the only file will have
+		// a shitload of doc comments preceeding the package name, and
+		// those comments are usually huge so this is bad
+		buffer := [512]byte { }
+		n, _ := file.Read(buffer[:])
+		text := string(buffer[:n])
+
+		packageIndex := strings.Index(text, "package")
+		if packageIndex < 0 { continue }
+		text = text[packageIndex:]
+		
+		newlineIndex := strings.Index(text, "\n")
+		if packageIndex > 0 { text = text[:newlineIndex] }
+
+		fields := strings.Fields(text)
+		if len(fields) < 2 { continue }
+		return fields[1], true
+	}
+	return "", false
+}

codec.go

@@ -0,0 +1,47 @@
+package hopp
+
+import "fmt"
+
+type anyInt16 interface { ~uint16 | ~int16 }
+type anyInt64 interface { ~uint64 | ~int64 }
+
+// decodeI16 decodes a 16 bit integer from the given data.
+func decodeI16[T anyInt16](data []byte) (T, error) {
+	if len(data) != 2 { return 0, fmt.Errorf("decoding int16: %w", ErrWrongBufferLength) }
+	return T(data[0]) << 8 | T(data[1]), nil
+}
+
+// encodeI16 encodes a 16 bit integer into the given buffer.
+func encodeI16[T anyInt16](buffer []byte, value T) error {
+	if len(buffer) != 2 { return fmt.Errorf("encoding int16: %w", ErrWrongBufferLength) }
+	buffer[0] = byte(value >> 8)
+	buffer[1] = byte(value)
+	return nil
+}
+
+// decodeI64 decodes a 64 bit integer from the given data.
+func decodeI64[T anyInt64](data []byte) (T, error) {
+	if len(data) != 8 { return 0, fmt.Errorf("decoding int64: %w", ErrWrongBufferLength) }
+	return T(data[0]) << 56 |
+		T(data[1]) << 48 |
+		T(data[2]) << 40 |
+		T(data[3]) << 32 |
+		T(data[4]) << 24 |
+		T(data[5]) << 16 |
+		T(data[6]) <<  8 |
+		T(data[7]), nil
+}
+
+// encodeI64 encodes a 64 bit integer into the given buffer.
+func encodeI64[T anyInt64](buffer []byte, value T) error {
+	if len(buffer) != 8 { return fmt.Errorf("encoding int64: %w", ErrWrongBufferLength) }
+	buffer[0] = byte(value >> 56)
+	buffer[1] = byte(value >> 48)
+	buffer[2] = byte(value >> 40)
+	buffer[3] = byte(value >> 32)
+	buffer[4] = byte(value >> 24)
+	buffer[5] = byte(value >> 16)
+	buffer[6] = byte(value >> 8)
+	buffer[7] = byte(value)
+	return nil
+}

connection.go

@@ -2,7 +2,7 @@ package hopp
 
 import "io"
 import "net"
-// import "time"
+import "time"
 
 const defaultSizeLimit int64 = 1024 * 1024 // 1 megabyte
 
@@ -23,8 +23,13 @@ type Conn interface {
 	// be called in a loop to avoid the connection locking up.
 	AcceptTrans() (Trans, error)
 
+	// SetDeadline operates is [net.Conn.SetDeadline] but for OpenTrans
+	// and AcceptTrans calls.
+	SetDeadline(t time.Time) error	
 	// SetSizeLimit sets a limit (in bytes) for how large messages can be.
-	// By default, this limit is 1 megabyte.
+	// By default, this limit is 1 megabyte. Note that this is only
+	// enforced when sending and receiving byte slices, and it does not
+	// apply to [Trans.SendWriter] or [Trans.ReceiveReader].
 	SetSizeLimit(limit int64)
 }
 
@@ -40,8 +45,6 @@ type Trans interface {
 	// unique within the connection. This method is safe for concurrent use.
 	ID() int64
 		
-	// TODO: add methods for setting send and receive deadlines
-		
 	// Send sends a message. This method is not safe for concurrent use.
 	Send(method uint16, data []byte) error
 	// SendWriter sends data written to an [io.Writer]. The writer must be
@@ -57,4 +60,12 @@ type Trans interface {
 	// previously opened through this function will be discarded. This
 	// method is not safe for concurrent use, and neither is its result.
 	ReceiveReader() (method uint16, data io.Reader, err error)
+
+	// See the documentation for [net.Conn.SetDeadline].
+	SetDeadline(time.Time) error
+	// TODO
+	// // See the documentation for [net.Conn.SetReadDeadline].
+	// SetReadDeadline(t time.Time) error
+	// // See the documentation for [net.Conn.SetWriteDeadline].
+	// SetWriteDeadline(t time.Time) error
 }

design/branched-generated-encoder.md

@@ -0,0 +1,128 @@
+# Branched Generated Decoder
+
+Pasted here because Tebitea is down
+
+## The problem
+
+TAPE is designed so that the decoder can gloss over data it does not understand.
+Technically the protocol allows for this, but I completely forgot to implement
+this in the generated decoder, oops. This would be trivial if TAPE messages were
+still flat tables, but they aren't, because those aren't useful enough. So,
+let's analyze the problem.
+
+## When it happens
+
+There are two reasons something might not match up with the expected data:
+
+The first and most obvious is unrecognized keys. If the key is not in the set of
+recognized keys for a KTV, it should leave the corresponding struct field blank.
+Once #6 has been implemented, throw an error if the data was not optional.
+
+The second is wrong types. If we are expecting KTV and get SBA, we should leave
+the data as empty. The aforementioned concern about #6 also applies here. We
+don't need to worry about special cases at the structure root, because it would
+be technically possible to make the structure root an option, so it really is
+just a normal value. Until #6, we will leave that blank too.
+
+## Preliminary ideas
+
+The first is going to be pretty simple. All we need to do is have a skimmer
+function that skims over TAPE data very, and then call that on the KTV value
+each time we run into a mystery key. It should only return an error if the
+structure of the data is malformed in such a way that it cannot continue to the
+next one. This should be stored in the tape package alongside the dynamic
+decoding functions, because they will essentially function the same way and
+could probably share lots of code.
+
+The second is a bit more complicated because of the existence of KTV and OTA
+because they are aggregate types. Go types work a bit differently, as if you
+have an array of an array of an array of ints, that information is represented
+in one place, whereas TAPE doesn't really do that. All of that information is
+sort of buried within the data structure, so we don't know what we will be
+decoding before we actually do it. Whenever we encounter a type we don't expect,
+we would need to abort decoding of the entire data structure, and then skim over
+whatever detritus is left, which would literally be in a half-decoded state. The
+fact that the code is generated flat and thus cannot use return or defer
+statements contributes to the complexity of this problem. We need to go up, but
+we can't. There is no up, only forward.
+
+Of course, the dynamic decoder does not have this problem in the first place
+because it doesn't expect anything, and constructs the destination to fit
+whatever it sees in the TAPE structure as it is decoding it. KTVs are completely
+dynamic because they are implemented as maps, so the only time it needs to
+completely comprehend a type is with OTAs. There is a function called typeOf
+that gets the type of the current tag and returns it as a reflect.Type, which
+necessitates recursion and peeking at OTAs and their elements.
+
+We could try to do the same thing in the generated decoder, comparing the
+determined type against the expected type to try to figure out whether we should
+decode an array or a table, etc. This is immediately problematic as it requires
+memory to be allocated, both for the peek buffer and the resulting tree of type
+information. If we end up with some crazy way to keep track of the types, that's
+only one half of the allocation problem and we would still be spending extra
+cycles going over all of that twice.
+
+## Performance constraints
+
+The generated decoder is supposed to blaze through data, and it can't do that if
+it does all the singing and dancing that the dynamic decoder does. It's time for
+some performance constraints:
+
+- No allocations, except as required to build the destination for the data
+- No redundant work
+- So, no freaking peeking
+- It should take well under 500 lines of generated code to decode one message of
+reasonable size (i.e. be careful not to bloat the binary)
+
+I'm not really going to do my usual thing here of making a slow version and
+speeding it up over time based on evidence and experimentation because these
+constraints inform the design so much it would be impossible to continue without
+them. I am 99% confident that these constraints will allow for an acceptable
+baseline of performance (for generated code) and we can still profile and
+micro-optimize later. This is good enough for me.
+Heavy solution
+
+There is a solution that might work very well which involves completely redoing
+the generated decoding code. We could create a function for every source type to
+destination type mapping that exists in protocol, and then compose them all
+together. The decoding methods for each message or type would be wrappers around
+the correct function for their root TAPE -> Go type mapping. The main benefit of
+this is it would make this problem a lot more manageable because the interface
+points between the data would be represented by function boundaries. This would
+allow the use of return and defer statements, and would allow more code sharing,
+producing a smaller binary. Go would probably inline these where needed.
+
+Would this work? Probably. More investigation is required to make sure. I want
+to stop re-writing things I don't need to. On the other hand, it is just the
+decoder.
+
+## Light solution
+
+TODO: find a solution that satisfies the performance constraints, keeps the same
+identical interface, and works off the same code. I am convinced this is doable,
+and it might even allow us to extract more data from an unexpected structure.
+However, continuing this way might introduce unmanageable complexity. It is
+already a little unmanageable and I am just one pony (kind of).
+
+## Implementation
+
+Heavy solution is going to work here, applied to only the points of
+`Generator.generateDecodeValue` where it decodes an aggregate data structure.
+That way, only minimal amounts of code need to be redone.
+
+Whenever a branch needs to happen, a call shall be generated, a deferred
+implementation request shall be added to a special FIFO queue within the
+generator. After generating data structures and their root decoding functions,
+the generator shall pick away at this queue until no requests remain. The
+generator shall accept new items during this process, so that recursion is
+possible. This is all to ensure it is only ever writing one function at a time
+
+The functions shall take a pointer to a type that accepts any type like (~) the
+destination's base type. We should also probably just call
+`Generator.generateDecodeValue` directly on user defined types this way, keeping
+their public `Decode` methods just for convenience.
+
+The tape package shall contain a skimming function that takes a decoder and a
+tag, and recursively consumes the decoder given the context of the tag. This
+shall be utilized by the decoder functions to skip over values if their tags
+or keys do not match up with what is expected.

design/pdl-compiler.md

@@ -0,0 +1,109 @@
+# PDL Compiler Specification
+
+Given one or more PDL files representing a protocol, the compiler shall generate
+a Go package named "protocol", which shall contain types for message and type
+definitions, as well as encoding and decoding methods.
+
+## Static Section
+
+The compiler shall write a static section alongside the generated code. It
+shall contain this text:
+
+```go
+// Table is a KTV table with an undefined schema.
+type Table map[uint16] any
+
+// Message is any message that can be sent along this protocol.
+type Message interface {
+	codec.Encodable
+	codec.Decodable
+
+	// Method returns the method code of the message.
+	Method() uint16
+}
+```
+
+## Preamble
+
+At the start of each file but after the package name, the compiler shall emit
+this text:
+
+```go
+/* # Do not edit this package by hand!
+ * 
+ * This file was automatically generated by the Holanet PDL compiler. The
+ * source file is located at <path>
+ * Please edit that file instead, and re-compile it to this location.
+ *
+ * HOPP, TAPE, METADAPT, PDL/0 (c) 2025 holanet.xyz
+ */
+```
+
+Where `<path>` is the path of the protocol definition file relative to the
+generated file.
+
+## Message Definitions
+
+For each defined message, the compiler shall generate a Go type named
+`MessageName`, where `Name` is the name of the message as written in its
+definition. The message shall be encodable, and shall have `Encode` and `Decode`
+methods as described below.
+
+All messages shall satisfy a `Message` interface, which is defined in the
+static section.
+
+## Type Definitions
+
+For each defined type, the compiler shall generate a Go type with the same name
+as written in its definition. The Go type shall be encodable, and shall have
+`EncodeValue`, `DecodeValue`, and `Tag` methods as described below.
+
+## Encoding and Decoding Methods
+
+Each message shall be given an `Encode` method and a `Decode` method,
+which shall take in a `codec.Encoder` and a `codec.Decoder` respectively. Both
+return an `(int, error)` pair describing the amount of bytes written and an
+error if the write stopped early. `Encode` shall encode the data within the
+message to the given encoder, and `Decode` shall decode data from the given
+decoder and place it in the type's value. The methods shall not retain or close
+any encoders or decoders they are given. Both methods shall have pointer
+receivers. In effect, these methods shall satisfy `codec.Encodable` and
+`codec.Decodable`.
+
+Each defined type shall be given an `EncodeValue` method and a `DecodeValue`
+method, which shall both take in a `tape.Tag`, then a `codec.Encoder` and a
+`codec.Decoder` respectively. These methods shall encode and decode the value
+according to the CN given by the tag. The TN shall be ignored. The message shall
+also have a method `Tag` that takes no arguments and returns the preferred tag
+of the type including the TN and CN.
+
+## Connection
+
+The compiler shall generate a `Conn` struct which embeds a `hopp.Conn`, which
+is the real "porcelain" of the generated code. It shall provide methods to
+create and accept transactions. Each transaction shall be a struct which embeds
+a `hopp.Trans`, and shall have methods for sending and receiving messages.
+
+### Sending
+
+To send a message along a transaction, the program shall:
+
+1. Obtain the method code from the message
+3. Obtain a writer from the connection using the method code
+4. Wrap the writer in a `codec.Encoder`
+5. Use the encoder to encode the message
+6. Close the writer
+
+### Receiving
+
+To receiving a message from a transaction, the program shall:
+
+1. Obtain a method code and reader from the connection
+2. Wrap the reader in a `codec.Decoder`
+3. Switch on the method code, and decode the correct message using the decoder
+4. Return the message to the caller as a value
+
+The recieve function must return the message as a value instead of a pointer in
+order to avoid making an allocation. Because of this, the return value must be
+`any` instead of `Message`. The caller must then use a type switch to figure out
+what message was sent.

design/pdl-language.md

@@ -0,0 +1,116 @@
+# PDL Language Definition
+
+PDL allows defining a protocol using HOPP and TAPE.
+
+## Data Types
+
+| Syntax     | TN      | CN | Description
+| ---------- | ------- | -: | -----------
+| I5         | SI      |    | 
+| I8         | LSI     |  0 | 
+| I16        | LSI     |  1 | 
+| I32        | LSI     |  3 | 
+| I64        | LSI     |  7 | 
+| I128[^2]   | LSI     | 15 | 
+| I256[^2]   | LSI     | 31 | 
+| U5         | SI      |    | 
+| U8         | LI      |  0 | 
+| U16        | LI      |  1 | 
+| U32        | LI      |  3 | 
+| U64        | LI      |  7 | 
+| U128[^2]   | LI      | 15 | 
+| U256[^2]   | LI      | 31 | 
+| F16        | FP      |  1 | 
+| F32        | FP      |  3 | 
+| F64        | FP      |  7 | 
+| F128[^2]   | FP      | 15 | 
+| F256[^2]   | FP      | 31 | 
+| Bool       | SI      |    | 
+| String     | SBA/LBA |  * | UTF-8 string
+| Buffer     | SBA/LBA |  * | Byte array
+| []\<TYPE\> | OTA     |  * | Array of any type[^1]
+| Table      | KTV     |  * | Table with undefined schema
+| {...}      | KTV     |  * | Table with defined schema
+| Any        | *       |  * | Value of an undefined type
+
+[^1]: Excluding SI and SBA. I5 and U5 cannot be used in an array, but String and
+Buffer are simply forced to use their "long" variant.
+
+[^2]: Some systems may lack support for this.
+
+## Tokens
+
+PDL files are divided into tokens, which assemble together into larger language
+structures. They are separated by whitespace.
+
+| Name     | Syntax             | Description
+| -------- | ------------------ | -----------
+| Method   | `M[0-9A-Fa-f]{4}`  | A 16-bit hexadecimal method code.
+| Key      | `[0-9A-Fa-f]{4}`   | A 16-bit hexadecimal table key.
+| Ident    | `[A-Z][A-Za-z0-9]` | An identifier.
+| Comma    | `,`                | A comma separator.
+| LBrace   | `{`                | A left curly brace.
+| RBrace   | `}`                | A right curly brace.
+| LBracket | `[`                | A left square bracket.
+| RBracket | `]`                | A right square bracket.
+| Comment  | `\/\/.*$`          | A doc comment starting with a double-slash.
+
+## Syntax
+
+Types are expressed with an Ident. A table can be used by either writing the
+name of the type (Table), or by defining a schema with curly braces. Arrays must
+be expressed using two matching square brackets before their element type.
+
+A table schema contains comma-separated fields in-between its braces. Each field
+has three parts: the key number (Key), the field name (Ident), and the field
+type. Tables, Arrays, etc. can be nested.
+
+Files directly contain messages and types, which start with a Method token and
+an Ident token respectively. A message consists of the method code (Method), the
+message name (Ident), and the message's root type. This is usually a table, but
+can be anything.
+
+Messages, types, and table fields can all have doc comments preceding them,
+which are used to generate documentation for the protocol. The syntax is the
+same as Go's (for now). Comments aren't allowed anywhere else.
+
+Here is an example of all that:
+
+```
+// Connect is sent from the client to the server as the first message of an
+// authenticated transaction.
+M0000 Connect {
+	0000 Name String,
+	0001 Password String,
+}
+
+// UserList is sent from the server to the client in response to a Connect
+// message.
+M0001 UserList {
+	0000 Users []User,
+}
+
+// User holds profile information about a single user.
+User {
+	0000 Name      String,
+	0001 Bio       String,
+	0002 Followers U32,
+}
+```
+
+## EBNF Description
+
+Below is an EBNF description of the language.
+
+```
+<file>    -> (<message> | <typedef)*
+<method>  -> /M[0-9A-Fa-f]{4}/
+<key>     -> /[0-9A-Fa-f]{4}/
+<ident>   -> /[A-Z][A-Za-z0-9]/
+<field>   -> <key> <ident> <type>
+<type> -> <ident>
+        | "[" "]" <type>
+        | "{" (<comment>* <field> ",")* [<comment>* <field>] "}"
+<message> -> <comment>* <method> <ident> <type>
+<typedef> -> <comment>* <ident> <type>
+```

design/protocol.md

@@ -18,12 +18,10 @@ dependant on which transport is being used.
 A message refers to a block of octets sent within a transaction, paired with an
 unsigned 16-bit method code. The order of messages within a given transaction is
 preserved, but the order of messages accross the entire connection is not
-guaranteed.
-
-The message payload must be 65,535 (unsigned 16-bit integer limit) octets or
-smaller in length. This does not include the method code. Applications are free
-to send whatever data they wish as the payload, but TAPE is recommended for
-encoding it.
+guaranteed. There is no functional limit on the size of a message payload, but
+there may be one depending on which
+[METADAPT sub-protocol](#message-and-transaction-demarcation-protocol-metadapt)
+is in use.
 
 Method codes should be written in upper-case base 16 with the prefix "M" in
 logs, error messages, documentation, etc. For example, the method code 62,206 in
@@ -37,88 +35,79 @@ fucking with you.
 ## Table Pair Encoding (TAPE)
 The Table Pair Encoding (TAPE) scheme is a method for encoding structured data
 within HOPP messages. It defines standard binary encoding methods for common
-data types, as well as a corruption-resistant table structure that maps numeric
-IDs to values. It is designed to allow applications to be presented with data
-they are not equipped to handle while continuing to function normally. This
-enables backwards compatibile application protocol changes.
+data types, as well as aggregate data types such as tables and arrays. It is
+designed to allow applications to be presented with data they are not equipped
+to handle while continuing to function normally. This enables backwards
+compatibile application protocol changes.
 
-### Table Structure
-A table is divided into two sections: the header, and the values. The header
-begins with the number (U16) of pairs in the table, which is then followed by
-that many tag-offset pairs. A tag-offset pair consists of a numerical (U16) tag,
-followed the position (U16) of the value relative to the start of the values
-section. The values section contains the value data for each pair, where the
-start of each value is determined by its offset, and the end is determined by
-the offset of the next value, or the end of the message if there is no value
-after it.
+TAPE expresses types using tags. A tag is 8 bits in size, and is divided into
+two parts: the Type Number (TN), and the Configuration Number (CN). The TN is 3
+bits, and the CN is 5 bits. Both are interpreted as unsigned integers. Both
+sides of the connection must agree on the semantic meaning of the values and
+their arrangement.
 
-Both sections must be in the same order, and because of this, each value offset
-must be greater than or equal to the last. If a message has erratic structure
-(such as unordered or out-of-bounds offsets), implementations may opt to discard
-only the erratic pairs, as well as the pairs directly before those.
+A TAPE structure begins with one root, which consists of a tag followed by a
+payload. This is usually an aggregate data structure such as KTV to allow for
+several different values.
+
+TAPE is based on an encoding method previously developed by silt.
 
 ### Data Value Types
-The table below lists all data value types supported by TAPE.
+The table below lists all data value types supported by TAPE. They are discussed
+in detail in the following sections.
 
-| Name        | Size            | Description                 | Encoding Method
-| ----------- | --------------: | --------------------------- | ---------------
-| I8          |               1 | A signed 8-bit integer      | BETC
-| I16         |               2 | A signed 16-bit integer     | BETC
-| I32         |               4 | A signed 32-bit integer     | BETC
-| I64         |               8 | A signed 64-bit integer     | BETC
-| U8          |               1 | An unsigned 8-bit integer   | BEU
-| U16         |               2 | An unsigned 16-bit integer  | BEU
-| U32         |               4 | An unsigned 32-bit integer  | BEU
-| U64         |               8 | An unsigned 64-bit integer  | BEU
-| Array[^1]   |         SOP[^2] | An array of any above type  | PASTA
-| String      |             N/A | A UTF-8 string              | UTF-8
-| StringArray | n * 2 + SOP[^2] | An array the String type    | VILA
+| TN | Bits | Name | Description
+| -: | ---: | ---- | -----------
+|  0 |  000 | SI   | Small integer
+|  1 |  001 | LI   | Large integer
+|  2 |  010 | FP   | Floating point
+|  3 |  011 | SBA  | Small byte array
+|  4 |  100 | LBA  | Large byte array
+|  5 |  101 | OTA  | One-tag array
+|  6 |  110 | KTV  | Key-tag-value table
+|  7 |  111 | N/A  | Reserved
 
-[^1]: Array types are written as <E>Array, where <E> is the element type. For
-example, an array of I32 would be written as I32Array. StringArray still follows
-this rule, even though it is encoded differently from other arrays. Nesting
-arrays inside of arrays is prohibited. This problem can be avoided in most cases
-by effectively utilizing the table structure, or by improving the design of
-your protocol.
+#### Small Integer (SI)
+SI encodes an integer of up to 5 bits, which are stored in the CN. It has no
+payload. Whether the bits are interpreted as unsigned or as signed two's
+complement is semantic information and must be agreed upon by both sides of the
+connection. Thus, the value may range from 0 to 31 if unsigned, and from -16 to
+17 if signed.
 
-[^2]: SOP (sum of parts) refers to the sum of the size of every item in a data
-structure.
+#### Large Integer (LI)
+LI encodes an integer of up to 256 bits, which are stored in the payload. The
+length of the payload (in bytes) is CN + 1. The integer is big-endian. Whether
+the payload is interpreted as unsigned or as signed two's complement is semantic
+information and must be agreed upon by both sides of the connection. Thus, the
+value may range from 0 to 31 if unsigned, and from -16 to 17 if signed.
 
-### Encoding Methods
-Below are all encoding methods supported by TAPE.
+#### Floating Point (FP)
+FP encodes an IEEE 754 floating point number of up to 256 bits, which are stored
+in the payload. The length of the payload (in bytes) is CN + 1. The only
+supported bit widths for floats are as follows: 16, 32, 64, 128, and 256.
 
-#### BETC
-Big-Endian, Two's Complement signed integer. The size is defined as the least
-amount of whole octets which can fit all bits in the integer, regardless if the
-bits are on or off. Therefore, the size cannot change at runtime.
+#### Small Byte Array (SBA)
+SBA encodes an array of up to 32 bytes, which are stored in the paylod. The
+CN determines the length of the payload in bytes.
 
-#### BEU
-Big-Endian, Unsigned integer. The size is defined as the least amount of whole
-octets which can fit all bits in the integer, regardless if the bits are on or
-off. Therefore, the size cannot change at runtime.
+#### Large Byte Array (LBA)
+LBA encodes an array of up to 2^256 bytes, which are stored in the second part
+of the payload, directly after the length. The length of the data length field
+in bytes is determined by the CN.
 
-#### PASTA
-Packed Single-Type Array. The size is defined as the size of an individual item
-times the number of items. Items are placed one after the other with no gaps
-in-between them, except as required to align the start of each item to the
-nearest whole octet. Items should be of the same type and must be of the same
-size.
+#### One-Tag Array (OTA)
+OTA encodes an array of up to 2^256 items, which are stored in the payload after
+the length field and the item tag, where the length field comes first. Each item
+must be the same length, as they all share the same tag. The length of the
+length field (in bytes) is CN + 1.
 
-#### UTF-8
-UTF-8 string. The size is defined as the least amount of whole octets which can
-fit all bits in the string, regardless if the bits are on or off. The size of
-this type is not fixed and may change at runtime, so this needs to be accounted
-for during use.
-
-#### VILA
-Variable Item Length Array. The size is defined as the least amount of whole
-octets which can fit each item plus one U16 per item. The size of this type is
-not fixed and may change at runtime, so this needs to be accounted for during
-use. The amount of items must be greater than zero. Items are each prefixed by
-their size (in octets) encoded as a U16, and they are placed one after the other
-with no gaps in-between them, except as required to align the start of each item
-to the nearest whole octet. Items should be of the same type but do not need to
-be of the same size.
+#### Key-Tag-Value Table (KTV)
+KTV encodes a table of up to 2^256 key/value pairs, which are stored in the
+payload after the length field. The pairs themselves consist of a 16-bit
+unsigned big-endian key followed by a tag and then the payload. Pair values can
+be of different types and sizes. The order of the pairs is not significant and
+should never be treated as such. The length of the length field (in bytes) is
+CN + 1.
 
 ## Transports
 A transport is a protocol that HOPP connections can run on top of. HOPP
@@ -169,7 +158,6 @@ sun will have expanded to swallow earth by then. Your connection will not last
 that long.
 
 #### Message Chunking
-
 The most significant bit of the payload size field of an MMB is called the Chunk
 Control Bit (CCB). If the CCB of a given MMB is zero, the represented message is
 interpreted as being self-contained and the data is processed immediately. If

dial.go

@@ -1,9 +1,9 @@
 package hopp
 
 import "net"
+import "errors"
 import "context"
 import "crypto/tls"
-import "github.com/quic-go/quic-go"
 
 // Dial opens a connection to a server. The network must be one of "quic",
 // "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, "quic4" and
@@ -19,9 +19,8 @@ type Dialer struct {
 }
 
 // Dial opens a connection to a server. The network must be one of "quic",
-// "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, "quic4" and
-// "quic6" don't do anything as the quic-go package doesn't seem to support this
-// behavior.
+// "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, quic is not
+// supported.
 func (diale Dialer) Dial(ctx context.Context, network, address string) (Conn, error) {
 	switch network {
 	case "quic", "quic4", "quic6": return diale.dialQUIC(ctx, network, address)
@@ -31,12 +30,7 @@ func (diale Dialer) Dial(ctx context.Context, network, address string) (Conn, er
 }
 
 func (diale Dialer) dialQUIC(ctx context.Context, network, address string) (Conn, error) {
-	// sorry i fucking lied to you about the network parameter. for all
-	// quic-go's bullshit bloat, it doesnt even support that. not even when
-	// instantiating a transport. go figure :/
-	conn, err := quic.DialAddr(ctx, address, tlsConfig(diale.TLSConfig), quicConfig())
-	if err != nil { return nil, err }
-	return AdaptB(quicMultiConn { underlying: conn }), nil
+	return nil, errors.New("quic is not yet implemented")
 }
 
 func (diale Dialer) dialUnix(ctx context.Context, network, address string) (Conn, error) {
@@ -60,15 +54,6 @@ func tlsConfig(conf *tls.Config) *tls.Config {
 	return conf
 }
 
-func quicConfig() *quic.Config {
-	return &quic.Config {
-		// TODO: perhaps we might want to put something here
-		// the quic config shouldn't be exported, just set up
-		// automatically. we can't have that strangely built quic-go
-		// package be part of the API, or any third-party packages for
-		// that matter. it must all be abstracted away.
-	}
-}
 
 func quicNetworkToUDPNetwork(network string) (string, error) {
 	switch network {

error.go

@@ -9,6 +9,7 @@ type Error string; const (
 	ErrIntegerOverflow    Error = "integer overflow"
 	ErrMessageMalformed   Error = "message is malformed"
 	ErrTablePairMissing   Error = "required table pair is missing"
+	ErrWrongBufferLength  Error = "wrong buffer length"
 )
 
 // Error implements the error interface.

generate/generate_test.go

@@ -0,0 +1,458 @@
+package generate
+
+// import "fmt"
+import "testing"
+
+// TODO: once everything has been ironed out, test that the public API of the
+// generator is equal to something specific
+
+var exampleProtocol = defaultProtocol()
+
+func init() {
+	exampleProtocol.Messages[0x0000] = Message {
+		Name: "Connect",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Password",  Type: TypeString { } },
+			},
+		},
+	}
+	exampleProtocol.Messages[0x0001] = Message {
+		Name: "UserList",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Users",  Type: TypeArray { Element: TypeNamed { Name: "User" } } },
+			},
+		},
+	}
+	exampleProtocol.Messages[0x0002] = Message {
+		Name: "Pulse",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Index",  Type: TypeInt { Bits: 5 } },
+				0x0001: Field { Name: "Offset", Type: TypeInt { Bits: 16, Signed: true }},
+				0x0002: Field { Name: "X",      Type: TypeFloat { Bits: 16 }},
+				0x0003: Field { Name: "Y",      Type: TypeFloat { Bits: 32 }},
+				0x0004: Field { Name: "Z",      Type: TypeFloat { Bits: 64 }},
+			},
+		},
+	}
+	exampleProtocol.Messages[0x0003] = Message {
+		Name: "NestedArray",
+		Type: TypeArray { Element: TypeArray { Element: TypeInt { Bits: 8 } } },
+	}
+	exampleProtocol.Messages[0x0004] = Message {
+		Name: "Integers",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "U5",  Type: TypeInt { Bits: 5  } },
+				0x0001: Field { Name: "U8",  Type: TypeInt { Bits: 8  } },
+				0x0002: Field { Name: "U16", Type: TypeInt { Bits: 16 } },
+				0x0003: Field { Name: "U32", Type: TypeInt { Bits: 32 } },
+				0x0004: Field { Name: "U64", Type: TypeInt { Bits: 64 } },
+				0x0006: Field { Name: "I8",  Type: TypeInt { Bits: 8,  Signed: true } },
+				0x0007: Field { Name: "I16", Type: TypeInt { Bits: 16, Signed: true } },
+				0x0008: Field { Name: "I32", Type: TypeInt { Bits: 32, Signed: true } },
+				0x0009: Field { Name: "I64", Type: TypeInt { Bits: 64, Signed: true } },
+				0x000B: Field { Name: "NI8", Type: TypeInt { Bits: 8,  Signed: true } },
+				0x000C: Field { Name: "NI16",Type: TypeInt { Bits: 16, Signed: true } },
+				0x000D: Field { Name: "NI32",Type: TypeInt { Bits: 32, Signed: true } },
+				0x000E: Field { Name: "NI64",Type: TypeInt { Bits: 64, Signed: true } },
+				0x000F: Field { Name: "Bool",Type: TypeBool { } },
+			},
+		},
+	}
+	exampleProtocol.Messages[0x0005] = Message {
+		Name: "Dynamic",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "AU8", Type: TypeAny { } },
+				0x0001: Field { Name: "AU16", Type: TypeAny { } },
+				0x0002: Field { Name: "AU32", Type: TypeAny { } },
+				0x0003: Field { Name: "AU64", Type: TypeAny { } },
+				0x0004: Field { Name: "AI8", Type: TypeAny { } },
+				0x0005: Field { Name: "AI16", Type: TypeAny { } },
+				0x0006: Field { Name: "AI32", Type: TypeAny { } },
+				0x0007: Field { Name: "AI64", Type: TypeAny { } },
+				0x0008: Field { Name: "AF32", Type: TypeAny { } },
+				0x0009: Field { Name: "AF64", Type: TypeAny { } },
+				0x000A: Field { Name: "AString", Type: TypeAny { } },
+				0x000B: Field { Name: "AArray", Type: TypeAny { } },
+				0x000C: Field { Name: "ATable", Type: TypeAny { } },
+				0x000D: Field { Name: "T0", Type: TypeTable { } },
+			},
+		},
+	}
+	exampleProtocol.Types["User"] = Typedef {
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Bio",       Type: TypeString { } },
+				0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+			},
+		},
+	}
+}
+
+func TestGenerateRunEncodeDecode(test *testing.T) {
+	testGenerateRun(test, &exampleProtocol, "encode-decode", `
+		// imports
+	`, `
+		log.Println("MessageConnect")
+		messageConnect := MessageConnect {
+			Name: "rarity",
+			Password: "gems",
+		}
+		testEncodeDecode(
+			&messageConnect,
+			tu.S(0xE0, 0x02).AddVar(
+				[]byte { 0x00, 0x00, 0x86, 'r', 'a', 'r', 'i', 't', 'y' },
+				[]byte { 0x00, 0x01, 0x84, 'g', 'e', 'm', 's' },
+				))
+		log.Println("MessageUserList")
+		messageUserList := MessageUserList {
+			Users: []User {
+				User {
+					Name: "rarity",
+					Bio: "asdjads",
+					Followers: 0x324,
+				},
+				User {
+					Name: "deez nuts",
+					Bio: "logy",
+					Followers: 0x8000,
+				},
+				User {
+					Name: "creekflow",
+					Bio: "im creekflow",
+					Followers: 0x3894,
+				},
+			},
+		}
+		testEncodeDecode(
+			&messageUserList,
+			tu.S(0xE0, 0x01, 0x00, 0x00,
+				0xC0, 0x03, 0xE0,
+					).Add(0x03).AddVar(
+						[]byte { 0x00, 0x00, 0x86, 'r', 'a', 'r', 'i', 't', 'y' },
+						[]byte { 0x00, 0x01, 0x87, 'a', 's', 'd', 'j', 'a', 'd', 's' },
+						[]byte { 0x00, 0x02, 0x23, 0x00, 0x00, 0x03, 0x24 },
+					).Add(0x03).AddVar(
+						[]byte { 0x00, 0x00, 0x89, 'd', 'e', 'e', 'z', ' ', 'n', 'u', 't', 's' },
+						[]byte { 0x00, 0x01, 0x84, 'l', 'o', 'g', 'y' },
+						[]byte { 0x00, 0x02, 0x23, 0x00, 0x00, 0x80, 0x00 },
+					).Add(0x03).AddVar(
+						[]byte { 0x00, 0x00, 0x89, 'c', 'r', 'e', 'e', 'k', 'f', 'l', 'o', 'w' },
+						[]byte { 0x00, 0x01, 0x8C, 'i', 'm', ' ', 'c', 'r', 'e', 'e', 'k', 'f',
+							'l', 'o', 'w' },
+						[]byte { 0x00, 0x02, 0x23, 0x00, 0x00, 0x38, 0x94 },
+				))
+		log.Println("MessagePulse")
+		messagePulse := MessagePulse {
+			Index: 9,
+			Offset: -0x3521,
+			X: 45.375,
+			Y: 294.1,
+			Z: 384729384.234892034,
+		}
+		testEncodeDecode(
+			&messagePulse,
+			tu.S(0xE0, 0x05).AddVar(
+				[]byte { 0x00, 0x00, 0x09 },
+				[]byte { 0x00, 0x01, 0x41, 0xCA, 0xDF },
+				[]byte { 0x00, 0x02, 0x61, 0x51, 0xAC },
+				[]byte { 0x00, 0x03, 0x63, 0x43, 0x93, 0x0C, 0xCD },
+				[]byte { 0x00, 0x04, 0x67, 0x41, 0xB6, 0xEE, 0x81, 0x28, 0x3C, 0x21, 0xE2 },
+				))
+		log.Println("MessageNestedArray")
+		uint8s := func(n int) []uint8 {
+			array := make([]uint8, n)
+			for index := range array {
+				array[index] = uint8(index + 1) | 0xF0
+			}
+			return array
+		}
+		messageNestedArray := MessageNestedArray {
+			uint8s(6),
+			uint8s(35),
+		}
+		testEncodeDecode(
+			&messageNestedArray,
+			tu.S(0xC0, 0x02, 0xC0,
+				0x06, 0x20, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6,
+				35,   0x20, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6,
+				            0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC,
+				            0xFD, 0xFE, 0xFF, 0xF0, 0xF1, 0xF2,
+				            0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,
+				            0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE,
+				            0xFF, 0xF0, 0xF1, 0xF2, 0xF3))
+		log.Println("MessageIntegers")
+		messageIntegers := MessageIntegers {
+			U5:   0x13,
+			U8:   0xC9,
+			U16:  0x34C9,
+			U32:  0x10E134C9,
+			U64:  0x639109BC10E134C9,
+			I8:   0x35,
+			I16:  0x34C9,
+			I32:  0x10E134C9,
+			I64:  0x639109BC10E134C9,
+			NI8:  -0x35,
+			NI16: -0x34C9,
+			NI32: -0x10E134C9,
+			NI64: -0x639109BC10E134C9,
+			Bool: true,
+		}
+		testEncodeDecode(
+			&messageIntegers,
+			tu.S(0xE0, 14).AddVar(
+				[]byte { 0x00, 0x00, 0x13 },
+				[]byte { 0x00, 0x01, 0x20, 0xC9 },
+				[]byte { 0x00, 0x02, 0x21, 0x34, 0xC9 },
+				[]byte { 0x00, 0x03, 0x23, 0x10, 0xE1, 0x34, 0xC9 },
+				[]byte { 0x00, 0x04, 0x27, 0x63, 0x91, 0x09, 0xBC, 0x10, 0xE1, 0x34, 0xC9 },
+				[]byte { 0x00, 0x06, 0x40, 0x35 },
+				[]byte { 0x00, 0x07, 0x41, 0x34, 0xC9 },
+				[]byte { 0x00, 0x08, 0x43, 0x10, 0xE1, 0x34, 0xC9 },
+				[]byte { 0x00, 0x09, 0x47, 0x63, 0x91, 0x09, 0xBC, 0x10, 0xE1, 0x34, 0xC9 },
+				[]byte { 0x00, 0x0B, 0x40, 0xCB },
+				[]byte { 0x00, 0x0C, 0x41, 0xCB, 0x37 },
+				[]byte { 0x00, 0x0D, 0x43, 0xEF, 0x1E, 0xCB, 0x37 },
+				[]byte { 0x00, 0x0E, 0x47, 0x9C, 0x6E, 0xF6, 0x43, 0xEF, 0x1E, 0xCB, 0x37 },
+				[]byte { 0x00, 0x0F, 0x01 },
+				))
+		log.Println("MessageDynamic")
+		messageDynamic := MessageDynamic {
+			AU8:     uint8(0x23),
+			AU16:    uint16(0x3247),
+			AU32:    uint32(0x87324523),
+			AU64:    uint64(0x3284029034098234),
+			AI8:     int8(0x23),
+			AI16:    int16(0x3247),
+			AI32:    int32(0x57324523),
+			AI64:    int64(0x3284029034098234),
+			AF32:    float32(2342.2378),
+			AF64:    float64(324.8899992),
+			AString: "fox bed",
+			AArray:  []int16 { 0x7, 0x6, 0x5, 0x4 },
+			ATable: map[uint16] any {
+				0x0001: int8(0x8),
+				0x0002: float64(4.4),
+			},
+			T0: map[uint16] any {
+				0x0001: float32(489.5),
+				0x0002: "hi",
+				0x0003: uint16(0x3992),
+			},
+		}
+		testEncodeDecode(
+			&messageDynamic,
+			tu.S(0xE0, 14).AddVar(
+				[]byte { 0x00, 0x00, 0x20, 0x23 },
+				[]byte { 0x00, 0x01, 0x21, 0x32, 0x47 },
+				[]byte { 0x00, 0x02, 0x23, 0x87, 0x32, 0x45, 0x23 },
+				[]byte { 0x00, 0x03, 0x27, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34 },
+				[]byte { 0x00, 0x04, 0x40, 0x23 },
+				[]byte { 0x00, 0x05, 0x41, 0x32, 0x47 },
+				[]byte { 0x00, 0x06, 0x43, 0x57, 0x32, 0x45, 0x23 },
+				[]byte { 0x00, 0x07, 0x47, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34 },
+				[]byte { 0x00, 0x08, 0x63, 0x45, 0x12, 0x63, 0xCE },
+				[]byte { 0x00, 0x09, 0x67, 0x40, 0x74, 0x4E, 0x3D, 0x6F, 0xCD, 0x17, 0x75 },
+				[]byte { 0x00, 0x0A, 0x87, 'f', 'o', 'x', ' ', 'b', 'e', 'd' },
+				[]byte { 0x00, 0x0B, 0xC0, 0x04, 0x41,
+					0x00, 0x07,
+					0x00, 0x06,
+					0x00, 0x05,
+					0x00, 0x04 },
+				[]byte { 0x00, 0x0C, 0xE0, 0x02,
+					0x00, 0x01, 0x40, 0x08,
+					0x00, 0x02, 0x67, 0x40, 0x11, 0x99, 0x99, 0x99, 0x99, 0x99, 0x9A },
+				[]byte { 0x00, 0x0D, 0xE0, 0x03, // ERR
+					0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00,
+					0x00, 0x02, 0x82, 'h', 'i',
+					0x00, 0x03, 0x21, 0x39, 0x92 },
+				))
+	`)
+}
+
+func TestGenerateRunDecodeWrongType(test *testing.T) {
+	protocol := defaultProtocol()
+	protocol.Messages[0x0000] = Message {
+		Name: "Uint5",
+		Type: TypeInt { Bits: 5 },
+	}
+	protocol.Messages[0x0001] = Message {
+		Name: "Uint8",
+		Type: TypeInt { Bits: 8 },
+	}
+	protocol.Messages[0x0002] = Message {
+		Name: "Uint16",
+		Type: TypeInt { Bits: 16 },
+	}
+	protocol.Messages[0x0003] = Message {
+		Name: "Uint32",
+		Type: TypeInt { Bits: 32 },
+	}
+	protocol.Messages[0x0004] = Message {
+		Name: "Uint64",
+		Type: TypeInt { Bits: 64 },
+	}
+	protocol.Messages[0x0005] = Message {
+		Name: "Int8",
+		Type: TypeInt { Bits: 8 },
+	}
+	protocol.Messages[0x0006] = Message {
+		Name: "Int16",
+		Type: TypeInt { Bits: 16 },
+	}
+	protocol.Messages[0x0007] = Message {
+		Name: "Int32",
+		Type: TypeInt { Bits: 32 },
+	}
+	protocol.Messages[0x0008] = Message {
+		Name: "Int64",
+		Type: TypeInt { Bits: 64 },
+	}
+	protocol.Messages[0x0009] = Message {
+		Name: "String",
+		Type: TypeString { },
+	}
+	protocol.Messages[0x000A] = Message {
+		Name: "Buffer",
+		Type: TypeBuffer { },
+	}
+	protocol.Messages[0x000B] = Message {
+		Name: "StringArray",
+		Type: TypeArray { Element: TypeString { } },
+	}
+	protocol.Messages[0x000C] = Message {
+		Name: "Table",
+		Type: TypeTable { },
+	}
+	protocol.Messages[0x000D] = Message {
+		Name: "TableDefined",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Password",  Type: TypeString { } },
+			},
+		},
+	}
+	
+	testGenerateRun(test, &protocol, "decode-wrong-type", `
+		// imports
+	`, `
+		datas := [][]byte {
+			/* int8     */ []byte { byte(tape.LSI.WithCN(0)), 0x45 },
+			/* int16    */ []byte { byte(tape.LSI.WithCN(1)), 0x45, 0x67 },
+			/* int32    */ []byte { byte(tape.LSI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
+			/* int64    */ []byte { byte(tape.LSI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
+			/* uint5    */ []byte { byte(tape.SI.WithCN(12)) },
+			/* uint8    */ []byte { byte(tape.LI.WithCN(0)), 0x45 },
+			/* uint16   */ []byte { byte(tape.LI.WithCN(1)), 0x45, 0x67 },
+			/* uint32   */ []byte { byte(tape.LI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
+			/* uint64   */ []byte { byte(tape.LI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
+			/* string   */ []byte { byte(tape.SBA.WithCN(7)), 'p', 'u', 'p', 'e', 'v', 'e', 'r' },
+			/* []byte   */ []byte { byte(tape.SBA.WithCN(5)), 'b', 'l', 'a', 'r', 'g' },
+			/* []string */ []byte {
+				byte(tape.OTA.WithCN(0)), 2, byte(tape.LBA.WithCN(0)),
+				0x08, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23,
+				0x05, 0x11, 0x11, 0x11, 0x11, 0x11,
+			},
+			/* map[uint16] any */ []byte {
+				byte(tape.KTV.WithCN(0)), 2,
+				0x02, 0x23, byte(tape.LSI.WithCN(1)), 0x45, 0x67,
+				0x02, 0x23, byte(tape.LI.WithCN(3)),  0x45, 0x67, 0x89, 0xAB,
+			},
+		}
+
+		
+		for index, data := range datas {
+			log.Printf("data %2d %v [%s]", index, tape.Tag(data[0]), tu.HexBytes(data[1:]))
+			// integers should only assign to other integers
+			if index > 8 {
+				cas := func(destination Message) {
+					n, err := destination.Decode(tape.NewDecoder(bytes.NewBuffer(data)))
+					if err != nil { log.Fatalf("error: %v | n: %d", err, n) }
+					reflectValue := reflect.ValueOf(destination).Elem()
+					if reflectValue.CanInt() {
+						if reflectValue.Int() != 0 {
+							log.Fatalf(
+								"destination not zero: %v",
+								reflectValue.Elem().Interface())
+						}
+					} else {
+						if reflectValue.Uint() != 0 {
+							log.Fatalf(
+								"destination not zero: %v",
+								reflectValue.Elem().Interface())
+						}
+					}
+					if n != len(data) {
+						log.Fatalf("n not equal: %d != %d", n, len(data))
+					}
+				}
+				log.Println("- MessageInt8")
+				{ var dest MessageInt8;   cas(&dest) }
+				log.Println("- MessageInt16")
+				{ var dest MessageInt16;  cas(&dest) }
+				log.Println("- MessageInt32")
+				{ var dest MessageInt32;  cas(&dest) }
+				log.Println("- MessageInt64")
+				{ var dest MessageInt64;  cas(&dest) }
+				log.Println("- MessageUint8")
+				{ var dest MessageUint8;  cas(&dest) }
+				log.Println("- MessageUint16")
+				{ var dest MessageUint16; cas(&dest) }
+				log.Println("- MessageUint32")
+				{ var dest MessageUint32; cas(&dest) }
+				log.Println("- MessageUint64")
+				{ var dest MessageUint64; cas(&dest) }
+			}
+			arrayCase := func(destination Message) {
+				n, err := destination.Decode(tape.NewDecoder(bytes.NewBuffer(data)),)
+				if err != nil { log.Fatalf("error: %v | n: %d", err, n) }
+				reflectDestination := reflect.ValueOf(destination)
+				reflectValue := reflectDestination.Elem()
+				if reflectValue.Len() != 0 {
+					log.Fatalf("len(destination) not zero: %v", reflectValue.Interface())
+				}
+				if n != len(data) {
+					log.Fatalf("n not equal: %d != %d", n, len(data))
+				}
+			}
+			anyCase := func(destination Message) {
+				n, err := destination.Decode(tape.NewDecoder(bytes.NewBuffer(data)),)
+				if err != nil { log.Fatalf("error: %v | n: %d", err, n) }
+				reflectDestination := reflect.ValueOf(destination)
+				reflectValue := reflectDestination.Elem()
+				if reflectValue == reflect.Zero(reflectValue.Type()) {
+					log.Fatalf("len(destination) not zero: %v", reflectValue.Interface())
+				}
+				if n != len(data) {
+					log.Fatalf("n not equal: %d != %d", n, len(data))
+				}
+			}
+			// SBA/LBA types should only assign to other SBA/LBA types
+			if index != 9 && index != 10 {
+				log.Println("- MessageString")
+				{ var dest MessageString; arrayCase(&dest) }
+				log.Println("- MessageBuffer")
+				{ var dest MessageBuffer; arrayCase(&dest) }
+			}
+			// arrays should only assign to other arrays
+			if index != 11 {
+				log.Println("- MessageStringArray")
+				{ var dest MessageStringArray; arrayCase(&dest) }
+			}
+			// tables should only assign to other tables
+			if index != 12 {
+				log.Println("- MessageTable")
+				{ var dest = make(MessageTable); arrayCase(&dest) }
+				log.Println("- MessageTableDefined")
+				{ var dest MessageTableDefined; anyCase(&dest) }
+			}
+		}
+	`)
+}

generate/lex.go

@@ -0,0 +1,251 @@
+package generate
+
+import "io"
+import "bufio"
+import "unicode"
+import "unicode/utf8"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+const (
+	TokenMethod parse.TokenKind = iota
+	TokenKey
+	TokenIdent
+	TokenComma
+	TokenLBrace
+	TokenRBrace
+	TokenLBracket
+	TokenRBracket
+	TokenComment
+)
+
+var tokenNames = map[parse.TokenKind] string {
+	TokenMethod:   "Method",
+	TokenKey:      "Key",
+	TokenIdent:    "Ident",
+	TokenComma:    "Comma",
+	TokenLBrace:   "LBrace",
+	TokenRBrace:   "RBrace",
+	TokenLBracket: "LBracket",
+	TokenRBracket: "RBracket",
+	TokenComment:  "Comment",
+}
+
+func Lex(fileName string, reader io.Reader) (parse.Lexer, error) {
+	lex := &lexer {
+		fileName: fileName,
+		lineScanner: bufio.NewScanner(reader),
+	}
+	lex.nextRune()
+	return lex, nil
+}
+
+type lexer struct {
+	fileName    string
+	lineScanner *bufio.Scanner
+	rune        rune
+	line        string
+	lineFood    string
+	
+	offset   int
+	row      int
+	column   int
+
+	eof bool
+
+}
+
+func (this *lexer) Next() (parse.Token, error) {
+	token, err := this.nextInternal()
+	if err == io.EOF { err = this.errUnexpectedEOF() }
+	return token, err
+}
+
+func (this *lexer) nextInternal() (token parse.Token, err error) {
+	err = this.skipWhitespace()
+	token.Position = this.pos()
+	if this.eof {
+		token.Kind = parse.EOF
+		err = nil
+		return
+	}
+	if err != nil { return }
+
+	appendRune := func () {
+		token.Value += string(this.rune)
+		err = this.nextRune()
+	}
+
+	doNumber := func () {
+		for isDigit(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+			if err != nil { return }
+		}
+	}
+
+	unexpected := func() error {
+		if unicode.IsPrint(this.rune) {
+			return parse.Errorf (
+				this.pos(), "unexpected rune '%c'",
+				this.rune)
+		} else {
+			return parse.Errorf (
+				this.pos(), "unexpected rune %U",
+				this.rune)
+		}
+	}
+
+	defer func () {
+		newPos := this.pos()
+		newPos.End -- // TODO figure out why tf we have to do this
+		token.Position = token.Position.Union(newPos)
+	} ()
+
+	switch {
+	// Method
+	case this.rune == 'M':
+		token.Kind = TokenMethod
+		err = this.nextRune()
+		if err != nil { return }
+		doNumber()
+		if this.eof { err = nil; return }
+	// Key
+	case isDigit(this.rune):
+		token.Kind = TokenKey
+		doNumber()
+		if this.eof { err = nil; return }
+	// Ident
+	case unicode.IsUpper(this.rune):
+		token.Kind = TokenIdent
+		for unicode.IsLetter(this.rune) || isDigit(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+			if err != nil { return }
+		}
+	// Comma
+	case this.rune == ',':
+		token.Kind = TokenComma
+		appendRune()
+		if this.eof { err = nil; return }
+	// LBrace
+	case this.rune == '{':
+		token.Kind = TokenLBrace
+		appendRune()
+		if this.eof { err = nil; return }
+	// RBrace
+	case this.rune == '}':
+		token.Kind = TokenRBrace
+		appendRune()
+		if this.eof { err = nil; return }
+	// LBracket
+	case this.rune == '[':
+		token.Kind = TokenLBracket
+		appendRune()
+		if this.eof { err = nil; return }
+	// RBracket
+	case this.rune == ']':
+		token.Kind = TokenRBracket
+		appendRune()
+		if this.eof { err = nil; return }
+	// Comment
+	case this.rune == '/':
+		token.Kind = TokenComment
+		appendRune()
+		if this.eof { return }
+		if this.rune != '/' {
+			err = unexpected()
+			return
+		}
+		for this.rune != '\n' {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
+	default:
+		err = unexpected()
+	}
+
+	return
+}
+
+func (this *lexer) nextRune() error {
+	if this.lineFood == "" {
+		ok := this.lineScanner.Scan()
+		if ok {
+			this.line     = this.lineScanner.Text()
+			this.lineFood = this.line
+			this.rune     = '\n'
+			this.column   = 0
+			this.row      ++
+		} else {
+			err := this.lineScanner.Err()
+			if err == nil {
+				this.eof = true
+				return io.EOF
+			} else {
+				return err
+			}
+		}
+	} else {
+		var ch   rune
+		var size int
+		for ch == 0 && this.lineFood != "" {
+			ch, size = utf8.DecodeRuneInString(this.lineFood)
+			this.lineFood = this.lineFood[size:]
+		}
+		this.rune = ch
+		this.column ++
+	}
+
+	return nil
+}
+
+func (this *lexer) skipWhitespace() error {
+	err := this.skipComment()
+	if err != nil { return err }
+	for isWhitespace(this.rune) {
+		err := this.nextRune()
+		if err != nil { return err }
+		err = this.skipComment()
+		if err != nil { return err }
+	}
+	return nil
+}
+
+func (this *lexer) skipComment() error {
+	if this.rune == ';' {
+		for this.rune != '\n' {
+			err := this.nextRune()
+			if err != nil { return err }
+		}
+	}
+	return nil
+}
+
+func (this *lexer) pos() parse.Position {
+	return parse.Position {
+		File:   this.fileName,
+		Line:   this.lineScanner.Text(),
+		Row:    this.row    - 1,
+		Start:  this.column - 1,
+		End:    this.column,
+	}
+}
+
+func (this *lexer) errUnexpectedEOF() error {
+	return parse.Errorf(this.pos(), "unexpected EOF")
+}
+
+func isWhitespace(char rune) bool {
+	switch char {
+	case ' ', '\t', '\r', '\n': return true
+	default: return false
+	}
+}
+
+func isDigit(char rune) bool {
+	return char >= '0' && char <= '9'
+}
+
+func isHexDigit(char rune) bool {
+	return isDigit(char) || char >= 'a' && char <= 'f' || char >= 'A' && char <= 'F'
+}

generate/lex_test.go

@@ -0,0 +1,65 @@
+package generate
+
+import "strings"
+import "testing"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+func TestLex(test *testing.T) {
+	lexer, err := Lex("test.pdl", strings.NewReader(`
+	// User holds profile information about a single user.
+	M0001 User {
+		0000 Name      String,
+		// dog water comment
+		
+		// Users is asdkjsagkj why
+		// 
+		// wow
+		0001 Users []User,
+		0002 Followers U32,
+	}`))
+	if err != nil { test.Fatal(parse.Format(err)) }
+
+	correctTokens := []parse.Token {
+		tok(TokenComment,  "// User holds profile information about a single user."),
+		tok(TokenMethod,   "0001"),
+		tok(TokenIdent,    "User"),
+		tok(TokenLBrace,   "{"),
+		tok(TokenKey,      "0000"),
+		tok(TokenIdent,    "Name"),
+		tok(TokenIdent,    "String"),
+		tok(TokenComma,    ","),
+		tok(TokenComment,  "// dog water comment"),
+		tok(TokenComment,  "// Users is asdkjsagkj why"),
+		tok(TokenComment,  "// "),
+		tok(TokenComment,  "// wow"),
+		tok(TokenKey,      "0001"),
+		tok(TokenIdent,    "Users"),
+		tok(TokenLBracket, "["),
+		tok(TokenRBracket, "]"),
+		tok(TokenIdent,    "User"),
+		tok(TokenComma,    ","),
+		tok(TokenKey,      "0002"),
+		tok(TokenIdent,    "Followers"),
+		tok(TokenIdent,    "U32"),
+		tok(TokenComma,    ","),
+		tok(TokenRBrace,   "}"),
+		tok(parse.EOF,     ""),
+	}
+
+	for index, correct := range correctTokens {
+		got, err := lexer.Next()
+		if err != nil { test.Fatal(parse.Format(err)) }
+		if got.Kind != correct.Kind || got.Value != correct.Value {
+			test.Logf("token %d mismatch", index)
+			test.Log("GOT:", tokenNames[got.Kind], got.Value)
+			test.Fatal("CORRECT:", tokenNames[correct.Kind], correct.Value)
+		}
+	}
+}
+
+func tok(kind parse.TokenKind, value string) parse.Token {
+	return parse.Token {
+		Kind:  kind,
+		Value: value,
+	}
+}

generate/misc_test.go

@@ -0,0 +1,131 @@
+package generate
+
+import "os"
+import "fmt"
+import "os/exec"
+import "testing"
+import "path/filepath"
+
+func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCase string) {
+	// reset data directory
+	dir := filepath.Join("test", title)
+	err := os.RemoveAll(dir)
+	if err != nil { test.Fatal(err) }
+	err = os.MkdirAll(dir, 0750)
+	if err != nil { test.Fatal(err) }
+
+	// open files
+	sourceFile, err := os.Create(filepath.Join(dir, "protocol.go"))
+	if err != nil { test.Fatal(err) }
+	defer sourceFile.Close()
+	mainFile, err := os.Create(filepath.Join(dir, "main.go"))
+	if err != nil { test.Fatal(err) }
+	defer mainFile.Close()
+
+	// generate protocol
+	generator := Generator {
+		Output: sourceFile,
+		PackageName: "main",
+	}
+	_, err = generator.Generate(protocol)
+	if err != nil { test.Fatal(err) }
+
+	// build static source files
+	imports = `
+		import "log"
+		import "bytes"
+		import "reflect"
+		import "git.tebibyte.media/sashakoshka/hopp/tape"
+		import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+		` + imports
+	setup := `log.Println("*** BEGIN TEST CASE OUTPUT ***")`
+	teardown := `log.Println("--- END TEST CASE OUTPUT ---")`
+	static := `
+		func testEncode(message Message, correct tu.Snake) {
+			buffer := bytes.Buffer { }
+			encoder := tape.NewEncoder(&buffer)
+			n, err := message.Encode(encoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			encoder.Flush()
+			got := buffer.Bytes()
+			log.Printf("got:     [%s]", tu.HexBytes(got))
+			log.Println("correct:", correct)
+			if n != len(got) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(got))
+			}
+			if ok, n := correct.Check(got); !ok {
+				log.Fatalln("not equal at", n)
+			}
+		}
+
+		func testDecode(correct Message, data any) {
+			var flat []byte
+			switch data := data.(type) {
+			case []byte:   flat = data
+			case tu.Snake: flat = data.Flatten()
+			}
+			message := reflect.New(reflect.ValueOf(correct).Elem().Type()).Interface().(Message)
+			log.Println("before: ", message)
+			decoder := tape.NewDecoder(bytes.NewBuffer(flat))
+			n, err := message.Decode(decoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			log.Println("got:    ", message)
+			log.Println("correct:", correct)
+			if n != len(flat) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(flat))
+			}
+			if !reflect.DeepEqual(message, correct) {
+				log.Fatalln("not equal")
+			}
+		}
+
+		// TODO: possibly combine the two above functions into this one,
+		// also take a data parameter here (snake)
+		func testEncodeDecode(message Message, data tu.Snake) {buffer := bytes.Buffer { }
+			log.Println("encoding:")
+			encoder := tape.NewEncoder(&buffer)
+			n, err := message.Encode(encoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			encoder.Flush()
+			got := buffer.Bytes()
+			log.Printf("got:     [%s]", tu.HexBytes(got))
+			log.Println("correct:", data)
+			if n != len(got) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(got))
+			}
+			if ok, n := data.Check(got); !ok {
+				log.Fatalln("not equal at", n)
+			}
+		
+			log.Println("decoding:")
+			destination := reflect.New(reflect.ValueOf(message).Elem().Type()).Interface().(Message)
+			flat := data.Flatten()
+			log.Println("before: ", tu.Describe(destination))
+			decoder := tape.NewDecoder(bytes.NewBuffer(flat))
+			n, err = destination.Decode(decoder)
+			if err != nil { log.Fatalf("at %d: %v\n", n, err) }
+			log.Println("got:    ", tu.Describe(destination))
+			log.Println("correct:", tu.Describe(message))
+			if n != len(flat) {
+				log.Fatalf("n incorrect: %d != %d\n", n, len(flat))
+			}
+			if !reflect.DeepEqual(destination, message) {
+				log.Fatalln("not equal")
+			}
+			
+		}
+		`
+	fmt.Fprintf(
+		mainFile, "package main\n%s\nfunc main() {\n%s\n%s\n%s\n}\n%s",
+		imports, setup, testCase, teardown, static)
+
+	// build and run test
+	command := exec.Command("go", "run", "./" + filepath.Join("generate", dir))
+	workingDirAbs, err := filepath.Abs("..")
+	if err != nil { test.Fatal(err) }
+	command.Dir = workingDirAbs
+	command.Env = os.Environ()
+	output, err := command.CombinedOutput()
+	test.Logf("output of %v:\n%s", command, output)
+	if err != nil { test.Fatal(err) }
+}

generate/parse.go

@@ -0,0 +1,239 @@
+package generate
+
+import "io"
+import "strings"
+import "strconv"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+func Parse(lx parse.Lexer) (*Protocol, error) {
+	protocol := defaultProtocol()
+	par := parser {
+		Parser: parse.Parser {
+			Lexer: lx,
+			TokenNames: tokenNames,
+		},
+		protocol: &protocol,
+	}
+	err := par.parse()
+	if err != nil { return nil, err }
+	return par.protocol, nil
+}
+
+func defaultProtocol() Protocol {
+	return Protocol {
+		Messages: make(map[uint16] Message),
+		Types: map[string] Typedef { },
+	}
+}
+
+func ParseReader(fileName string, reader io.Reader) (*Protocol, error) {
+	lx, err := Lex(fileName, reader)
+	if err != nil { return nil, err }
+	return Parse(lx)
+}
+
+type parser struct {
+	parse.Parser
+	protocol *Protocol
+}
+
+func (this *parser) parse() error {
+	err := this.Next()
+	if err != nil { return err }
+	for this.Token.Kind != parse.EOF {
+		err = this.parseTopLevel()
+		if err != nil { return err }
+	}
+	return nil
+}
+
+func (this *parser) parseTopLevel() error {
+	doc := ""
+	for {
+		err := this.ExpectDesc("message or typedef", TokenMethod, TokenIdent, TokenComment)
+		if err != nil { return err }
+		if this.EOF() { return nil }
+		if this.Kind() == TokenComment {
+			if doc != "" { doc += "\n" }
+			doc += this.parseComment(this.Value())
+			this.Next()
+		} else {
+			break
+		}
+	}
+
+	switch this.Kind() {
+	case TokenMethod: return this.parseMessage(doc)
+	case TokenIdent:  return this.parseTypedef(doc)
+	}
+	panic("bug")
+}
+
+func (this *parser) parseMessage(doc string) error {
+	err := this.Expect(TokenMethod)
+	if err != nil { return err }
+	method, err := this.parseHexNumber(this.Value(), 0xFFFF)
+	if err != nil { return err }
+	err = this.ExpectNext(TokenIdent)
+	if err != nil { return err }
+	name := this.Value()
+	err = this.Next()
+	if err != nil { return err }
+	typ, err := this.parseType()
+	if err != nil { return err }
+	this.protocol.Messages[uint16(method)] = Message {
+		Name: name,
+		Doc:  doc,
+		Type: typ,
+	}
+	return nil
+}
+
+func (this *parser) parseTypedef(doc string) error {
+	err := this.Expect(TokenIdent)
+	if err != nil { return err }
+	name := this.Value()
+	err = this.Next()
+	if err != nil { return err }
+	typ, err := this.parseType()
+	if err != nil { return err }
+	this.protocol.Types[name] = Typedef {
+		Doc:  doc,
+		Type: typ,
+	}
+	return nil
+}
+
+func (this *parser) parseType() (Type, error) {
+	err := this.ExpectDesc("type", TokenIdent, TokenLBracket, TokenLBrace)
+	if err != nil { return nil, err }
+
+	switch this.Kind() {
+	case TokenIdent:
+		switch this.Value() {
+		case "U8":     return TypeInt { Bits: 8   }, this.Next()
+		case "U16":    return TypeInt { Bits: 16  }, this.Next()
+		case "U32":    return TypeInt { Bits: 32  }, this.Next()
+		case "U64":    return TypeInt { Bits: 64  }, this.Next()
+		case "U128":   return TypeInt { Bits: 128 }, this.Next()
+		case "U256":   return TypeInt { Bits: 256 }, this.Next()
+		case "I8":     return TypeInt { Bits: 8,   Signed: true }, this.Next()
+		case "I16":    return TypeInt { Bits: 16,  Signed: true }, this.Next()
+		case "I32":    return TypeInt { Bits: 32,  Signed: true }, this.Next()
+		case "I64":    return TypeInt { Bits: 64,  Signed: true }, this.Next()
+		case "I128":   return TypeInt { Bits: 128, Signed: true }, this.Next()
+		case "I256":   return TypeInt { Bits: 256, Signed: true }, this.Next()
+		case "F16":    return TypeFloat { Bits: 16  }, this.Next()
+		case "F32":    return TypeFloat { Bits: 32  }, this.Next()
+		case "F64":    return TypeFloat { Bits: 64  }, this.Next()
+		case "F128":   return TypeFloat { Bits: 128 }, this.Next()
+		case "F256":   return TypeFloat { Bits: 256 }, this.Next()
+		case "String": return TypeString { }, this.Next()
+		case "Buffer": return TypeBuffer { }, this.Next()
+		case "Table":  return TypeTable { }, this.Next()
+		case "Any":    return TypeAny { }, this.Next()
+		case "Bool":   return TypeBool { }, this.Next()
+		}
+		return this.parseTypeNamed()
+	case TokenLBracket:
+		return this.parseTypeArray()
+	case TokenLBrace:
+		return this.parseTypeTable()
+	}
+	panic("bug")
+}
+
+func (this *parser) parseTypeNamed() (TypeNamed, error) {
+	err := this.Expect(TokenIdent)
+	if err != nil { return TypeNamed { }, err }
+	name := this.Value()
+	err = this.Next()
+	if err != nil { return TypeNamed { }, err }
+	return TypeNamed { Name: name }, nil
+}
+
+func (this *parser) parseTypeArray() (TypeArray, error) {
+	err := this.Expect(TokenLBracket)
+	if err != nil { return TypeArray { }, err }
+	err = this.ExpectNext(TokenRBracket)
+	if err != nil { return TypeArray { }, err }
+	err = this.Next()
+	if err != nil { return TypeArray { }, err }
+	typ, err := this.parseType()
+	if err != nil { return TypeArray { }, err }
+	return TypeArray { Element: typ }, nil
+}
+
+func (this *parser) parseTypeTable() (TypeTableDefined, error) {
+	err := this.Expect(TokenLBrace)
+	if err != nil { return TypeTableDefined { }, err }
+	err = this.Next()
+	if err != nil { return TypeTableDefined { }, err }
+	typ := TypeTableDefined {
+		Fields: make(map[uint16] Field),
+	}
+	for {
+		doc := ""
+		for {
+			err := this.ExpectDesc("table field", TokenKey, TokenRBrace, TokenComment)
+			if err != nil { return TypeTableDefined { }, err }
+			if this.Kind() == TokenComment {
+				if doc != "" { doc += "\n" }
+				doc += this.parseComment(this.Value())
+				this.Next()
+			} else {
+				break
+			}
+		}
+		if this.Is(TokenRBrace) {
+			break
+		}
+		key, field, err := this.parseField(doc)
+		if err != nil { return TypeTableDefined { }, err }
+		typ.Fields[key] = field
+		err = this.Expect(TokenComma, TokenRBrace)
+		if err != nil { return TypeTableDefined { }, err }
+		if this.Is(TokenRBrace) {
+			break
+		}
+		err = this.Next()
+		if err != nil { return TypeTableDefined { }, err }
+	}
+	err = this.Next()
+	if err != nil { return TypeTableDefined { }, err }
+	return typ, nil
+}
+
+func (this *parser) parseField(doc string) (uint16, Field, error) {
+	err := this.Expect(TokenKey)
+	if err != nil { return 0, Field { }, err }
+	key, err := this.parseHexNumber(this.Value(), 0xFFFF)
+	if err != nil { return 0, Field { }, err }
+	err = this.ExpectNext(TokenIdent)
+	if err != nil { return 0, Field { }, err }
+	name := this.Value()
+	err = this.Next()
+	if err != nil { return 0, Field { }, err }
+	typ, err := this.parseType()
+	if err != nil { return 0, Field { }, err }
+	return uint16(key), Field {
+		Name: name,
+		Doc:  doc,
+		Type: typ,
+	}, nil
+}
+
+func (this *parser) parseHexNumber(input string, maxValue int64) (int64, error) {
+	number, err := strconv.ParseInt(input, 16, 64)
+	if err != nil {
+		return 0, parse.Errorf(this.Pos(), "%v", err)
+	}
+	if maxValue > 0 && number > maxValue {
+		return 0, parse.Errorf(this.Pos(), "value too large (max %X)", maxValue)
+	}
+	return number, nil
+}
+
+func (this *parser) parseComment(input string) string {
+	return strings.TrimPrefix(strings.TrimPrefix(input, "//"), " ")
+}

generate/parse_test.go

@@ -0,0 +1,86 @@
+package generate
+
+import "fmt"
+import "strings"
+import "testing"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+func TestParse(test *testing.T) {
+	correct := defaultProtocol()
+	correct.Messages[0x0000] = Message {
+		Name: "Connect",
+		Doc:  "Connect is sent from the client to the server as the first message of an\nauthenticated transaction.",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Password",  Type: TypeString { } },
+			},
+		},
+	}
+	correct.Messages[0x0001] = Message {
+		Name: "UserList",
+		Doc:  "UserList is sent from the server to the client in response to a Connect\nmessage.",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Users",  Type: TypeArray { Element: TypeNamed { Name: "User" } } },
+			},
+		},
+	}
+	correct.Types["User"] = Typedef {
+		Doc:  "User holds profile information about a single user.",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Bio",       Type: TypeString { } },
+				0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+				0x0003: Field { Name: "Bouncy",    Type: TypeBool { } },
+			},
+		},
+	}
+	correct.Types["Anything"] = Typedef {
+		Type: TypeAny { },
+	}
+	test.Log("CORRECT:", &correct)
+	
+	got, err := ParseReader("test.pdl", strings.NewReader(`
+	// Connect is sent from the client to the server as the first message of an
+	// authenticated transaction.
+	M0000 Connect {
+		0000 Name String,
+		// Password is where you put your secrets, your shameful secrets
+		0001 Password String,
+	}
+	
+	// UserList is sent from the server to the client in response to a Connect
+	// message.
+	M0001 UserList {
+		0000 Users []User,
+	}
+	
+	// User holds profile information about a single user.
+	User {
+		0000 Name      String,
+		0001 Bio       String,
+		0002 Followers U32,
+		0003 Bouncy    Bool,
+	}
+
+	Anything Any
+	`))
+	if err != nil { test.Fatal(parse.Format(err)) }
+	test.Log("GOT:    ", got)
+
+	correctStr := fmt.Sprint(&correct)
+	gotStr     := fmt.Sprint(got)
+
+	if correctStr != gotStr {
+		test.Error("not equal")
+		for index := range min(len(correctStr), len(gotStr)) {
+			if correctStr[index] == gotStr[index] { continue }
+			test.Log("C:", correctStr[max(0, index - 8):min(len(correctStr), index + 8)])
+			test.Log("G:", gotStr[max(0, index - 8):min(len(gotStr), index + 8)])
+			break
+		}
+		test.FailNow()
+	}
+}

generate/protocol.go

@@ -1,244 +1,126 @@
 package generate
 
-import "io"
 import "fmt"
-import "errors"
-import "strconv"
-import "strings"
-import "github.com/gomarkdown/markdown"
-import "github.com/gomarkdown/markdown/ast"
-import "github.com/gomarkdown/markdown/parser"
+import "maps"
+import "slices"
+import "crypto/md5"
 
-// Protocol describes a protocol.
 type Protocol struct {
-	Messages []Message
+	Messages map[uint16] Message
+	Types    map[string] Typedef
 }
 
-// Message describes a protocol message.
 type Message struct {
-	Doc    string
-	Method uint16
 	Name string
-	Fields []Field
+	Doc  string
+	Type Type
+}
+
+type Typedef struct {
+	Doc  string
+	Type Type
+}
+
+type Type interface {
+	fmt.Stringer
+}
+
+type TypeInt struct {
+	Bits   int
+	Signed bool
+}
+
+func (typ TypeInt) String() string {
+	output := ""
+	if typ.Signed {
+		output += "I"
+	} else {
+		output += "U"
+	}
+	output += fmt.Sprint(typ.Bits)
+	return output
+}
+
+type TypeFloat struct {
+	Bits int
+}
+
+func (typ TypeFloat) String() string {
+	return fmt.Sprintf("F%d", typ.Bits)
+}
+
+type TypeBool struct { }
+
+func (TypeBool) String() string {
+	return "Bool"
+}
+
+type TypeString struct { }
+
+func (TypeString) String() string {
+	return "String"
+}
+
+type TypeBuffer struct { }
+
+func (TypeBuffer) String() string {
+	return "Buffer"
+}
+
+type TypeArray struct {
+	Element Type
+}
+
+func (typ TypeArray) String() string {
+	return fmt.Sprintf("[]%v", typ.Element)
+}
+
+type TypeTable struct { }
+
+func (TypeTable) String() string {
+	return "Table"
+}
+
+type TypeTableDefined struct {
+	Fields map[uint16] Field
+}
+
+func (typ TypeTableDefined) String() string {
+	output := "{"
+	for _, key := range slices.Sorted(maps.Keys(typ.Fields)) {
+		output += fmt.Sprintf("%04X %v", key, typ.Fields[key])
+	}
+	output += "}"
+	return output
 }
 
-// Field describes a named value within a message.
 type Field struct {
-	Doc      string
-	Tag      uint16
 	Name string
-	Optional bool
-	Type     string
+	Doc  string
+	Type Type
 }
 
-// ParseReader parses a protocol definition from a reader.
-func ParseReader(reader io.Reader) (*Protocol, error) {
-	data, err := io.ReadAll(reader)
-	if err != nil { return nil, err }
-	protocol := new(Protocol)
-	err = protocol.UnmarshalText(data)
-	if err != nil { return nil, err }
-	return protocol, nil
+func (field Field) String() string {
+	return fmt.Sprintf("%s %v", field.Name, field.Type)
 }
 
-// UnmarshalText unmarshals markdown-formatted text data into the protocol.
-func (this *Protocol) UnmarshalText(text []byte) error {
-	var state int; const (
-		stateIdle = iota
-		stateMessage
-		stateMessageDoc
-		stateMessageField
-	)
-
-	var message *Message
-	addMessage := func(method uint16, name string) {
-		this.Messages = append(this.Messages, Message {
-			Method: method,
-			Name:   name,
-		})
-		message = &this.Messages[len(this.Messages) - 1]
-	}
-
-	root := markdown.Parse(text, parser.New())
-	for _, node := range root.GetChildren() {
-		if node, ok := node.(*ast.Heading); ok {
-			if node.Level == 2 {
-				if removeBreaks(flatten(node)) == "Messages" {
-					state = stateMessage
-					continue
-				}
-			}
-
-			if node.Level > 3 {
-				state = stateIdle
-				continue
-			}
-
-			if state != stateIdle && node.Level == 3 {
-				heading := removeBreaks(flatten(node))
-				method, name, err := splitMessageHeading(heading)
-				if err != nil { return err }
-				addMessage(method, name)
-				state = stateMessageDoc
-			}
-		}
-
-		if state == stateIdle { continue }
-		if message == nil     { continue }
-
-		// TODO when we are adding text content to the doc comment, it
-		// might be wise to do stuff like indent lists and quotes so
-		// that go doc renders them correctly
-		switch node := node.(type) {
-		case *ast.Paragraph:
-			if message.Doc != "" { message.Doc += "\n\n" }
-			message.Doc += removeBreaks(flatten(node))
-		case *ast.BlockQuote:
-			if message.Doc != "" { message.Doc += "\n\n> " }
-			message.Doc += removeBreaks(flatten(node))
-		case *ast.List:
-			// FIXME format the list
-			if message.Doc != "" { message.Doc += "\n\n" }
-			message.Doc += removeBreaks(flatten(node))
-		case *ast.Table:
-			fields, err := processFieldTable(node)
-			if err != nil { return err}
-			message.Fields = append(message.Fields, fields...)
-		}
-	}
-	
-	return nil
+type TypeNamed struct {
+	Name string
 }
 
-func processFieldTable(node *ast.Table) ([]Field, error) {
-	fields := []Field { }
-	children := node.GetChildren()
-	if len(children) != 2 {
-		return nil, errors.New("malformed field table")
-	}
-
-	// get columns
-	columns := []string { }
-	if header, ok := children[0].(*ast.TableHeader); ok {
-		children := header.GetChildren()
-		if len(children) != 1 {
-			return nil, errors.New("malformed field table header")
-		}
-		if row, ok := header.Children[0].(*ast.TableRow); ok {
-			for _, cell := range row.GetChildren() {
-				if cell, ok := cell.(*ast.TableCell); ok {
-					columns = append(columns, flatten(cell))
-				}
-			}
-		} else {
-			return nil, errors.New("malformed field table header")
-		}
-		for index, column := range columns {
-			columns[index] = strings.ToLower(column)
-		}
-	} else {
-		return nil, errors.New("malformed field table: no header")
-	}
-
-	// get data
-	if body, ok := children[1].(*ast.TableBody); ok {
-		for _, node := range body.GetChildren() {
-		if row, ok := node.(*ast.TableRow); ok {
-			children := row.GetChildren()
-			if len(children) != len(columns) {
-				return nil, errors.New (
-					"malformed field table row: wrong " +
-					"number of columns")
-			}
-
-			field := Field { }
-		
-			for index, node := range children {
-			if cell, ok := node.(*ast.TableCell); ok {
-				text := flatten(cell)
-				switch columns[index] {
-				case "tag":
-					tag, err := parseTag(text)
-					if err != nil { return nil, err }
-					field.Tag = tag
-				case "name":
-					field.Name = text
-				case "required":
-					field.Optional = !parseBool(text)
-				case "optional":
-					field.Optional = parseBool(text)
-				case "type":
-					field.Type = text
-				case "comment", "purpose", "documentation":
-					field.Doc = text
-				}
-			}}
-
-			fields = append(fields, field)
-		}}
-	} else {
-		return nil, errors.New("malformed field table: no body")
-	}
-	return fields, nil
+func (typ TypeNamed) String() string {
+	return typ.Name
 }
 
-type nodeFlattener struct {
-	text string
-}
-func (this *nodeFlattener) String() string { return this.text }
-func (this *nodeFlattener) Visit(node ast.Node, entering bool) ast.WalkStatus {
-	if entering {
-		if node := node.AsLeaf(); node != nil {
-			this.text += string(node.Literal)
-		}
-	}
-	return ast.GoToNext
-}
-func flatten(node ast.Node) string {
-	flattener := new(nodeFlattener)
-	ast.Walk(node, flattener)
-	return flattener.text
+type TypeAny struct { }
+
+func (typ TypeAny) String() string {
+	return "Any"
 }
 
-
-func removeBreaks(text string) string {
-	text = strings.ReplaceAll(text, "\n", " ")
-	text = strings.ReplaceAll(text, "\r", "")
-	return text
-}
-
-func parseBool(text string) bool {
-	switch(strings.ToLower(text)) {
-	case "yes": return true
-	case "no": return false
-	case "true": return true
-	case "false": return false
-	}
-	return false
-}
-
-func parseTag(text string) (uint16, error) {
-	tag, err := strconv.ParseUint(text, 10, 16)
-	if err != nil {
-		return 0, fmt.Errorf("malformed tag '%s': %w", text, err)
-	}
-	return uint16(tag), nil
-}
-
-func splitMessageHeading(text string) (uint16, string, error) {
-	text = strings.TrimSpace(text)
-	methodText, name, ok := strings.Cut(text, " ")
-	if !ok {
-		return 0, "", fmt.Errorf(
-			"malformed message heading '%s': no message name",
-			text)
-	}
-	method, err := strconv.ParseUint(methodText, 16, 16)
-	if err != nil {
-		return 0, "", fmt.Errorf(
-			"malformed method number '%s': %w",
-			methodText, err)
-	}
-	name = strings.TrimSpace(name)
-	return uint16(method), name, nil
+func HashType(typ Type) [16]byte {
+	// TODO: if we ever want to make the compiler more efficient, this would
+	// be a good place to start, complex string concatenation in a hot path
+	// (sorta)
+	return md5.Sum([]byte(typ.String()))
 }

go.mod

@@ -3,20 +3,7 @@ module git.tebibyte.media/sashakoshka/hopp
 go 1.23.0
 
 require (
+	git.tebibyte.media/sashakoshka/go-cli v0.1.3
 	git.tebibyte.media/sashakoshka/go-util v0.9.1
-	github.com/gomarkdown/markdown v0.0.0-20241205020045-f7e15b2f3e62
-	github.com/quic-go/quic-go v0.48.2
-)
-
-require (
-	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
-	github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38 // indirect
-	github.com/onsi/ginkgo/v2 v2.9.5 // indirect
-	go.uber.org/mock v0.4.0 // indirect
-	golang.org/x/crypto v0.26.0 // indirect
-	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 // indirect
-	golang.org/x/mod v0.17.0 // indirect
-	golang.org/x/net v0.28.0 // indirect
-	golang.org/x/sys v0.23.0 // indirect
-	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
+	git.tebibyte.media/sashakoshka/goparse v0.2.0
 )

go.sum

@@ -1,60 +1,6 @@
+git.tebibyte.media/sashakoshka/go-cli v0.1.3 h1:tSkWjyx2JrGu6KotbXWSTKSYGGS1D4O3qwCrRoZuwbs=
+git.tebibyte.media/sashakoshka/go-cli v0.1.3/go.mod h1:JFA3wSdRkXxa4iQJWHfe3DokiG7Dh2XUJBzPmuVlbuY=
 git.tebibyte.media/sashakoshka/go-util v0.9.1 h1:eGAbLwYhOlh4aq/0w+YnJcxT83yPhXtxnYMzz6K7xGo=
 git.tebibyte.media/sashakoshka/go-util v0.9.1/go.mod h1:0Q1t+PePdx6tFYkRuJNcpM1Mru7wE6X+it1kwuOH+6Y=
-github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
-github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
-github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-logr/logr v1.2.4 h1:g01GSCwiDw2xSZfjJ2/T9M+S6pFdcNtFYsp+Y43HYDQ=
-github.com/go-logr/logr v1.2.4/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
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-github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
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-github.com/quic-go/quic-go v0.48.2/go.mod h1:yBgs3rWBOADpga7F+jJsb6Ybg1LSYiQvwWlLX+/6HMs=
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-golang.org/x/crypto v0.26.0 h1:RrRspgV4mU+YwB4FYnuBoKsUapNIL5cohGAmSH3azsw=
-golang.org/x/crypto v0.26.0/go.mod h1:GY7jblb9wI+FOo5y8/S2oY4zWP07AkOJ4+jxCqdqn54=
-golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 h1:vr/HnozRka3pE4EsMEg1lgkXJkTFJCVUX+S/ZT6wYzM=
-golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=
-golang.org/x/mod v0.17.0 h1:zY54UmvipHiNd+pm+m0x9KhZ9hl1/7QNMyxXbc6ICqA=
-golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
-golang.org/x/net v0.28.0 h1:a9JDOJc5GMUJ0+UDqmLT86WiEy7iWyIhz8gz8E4e5hE=
-golang.org/x/net v0.28.0/go.mod h1:yqtgsTWOOnlGLG9GFRrK3++bGOUEkNBoHZc8MEDWPNg=
-golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
-golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
-golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
-golang.org/x/text v0.17.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
-golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
-golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
-golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d h1:vU5i/LfpvrRCpgM/VPfJLg5KjxD3E+hfT1SH+d9zLwg=
-golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
-google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
-google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+git.tebibyte.media/sashakoshka/goparse v0.2.0 h1:uQmKvOCV2AOlCHEDjg9uclZCXQZzq2PxaXfZ1aIMiQI=
+git.tebibyte.media/sashakoshka/goparse v0.2.0/go.mod h1:tSQwfuD+EujRoKr6Y1oaRy74ZynatzkRLxjE3sbpCmk=

internal/testutil/testutil.go

@@ -0,0 +1,190 @@
+package testutil
+
+import "fmt"
+import "slices"
+import "reflect"
+import "strings"
+import "unicode"
+
+// Snake lets you compare blocks of data where the ordering of certain parts may
+// be swapped every which way. It is designed for comparing the encoding of
+// maps where the ordering of individual elements is inconsistent.
+//
+// The snake is divided into sectors, which hold a number of variations. For a
+// sector to be satisfied by some data, some ordering of it must match the data
+// exactly. for the snake to be satisfied by some data, its sectors must match
+// the data in order, but the internal ordering of each sector doesn't matter.
+type Snake []    []     []byte
+//         snake sector variation
+
+// S returns a new snake.
+func S(data ...byte) Snake {
+	return (Snake { }).Add(data...)
+}
+
+// AddVar returns a new snake with the given sector added on to it. Successive
+// calls of this method can be chained together to create a big ass snake.
+func (sn Snake) AddVar(sector ...[]byte) Snake {
+	slice := make(Snake, len(sn) + 1)
+	copy(slice, sn)
+	slice[len(slice) - 1] = sector
+	return slice
+}
+
+// Add is like AddVar, but adds a sector with only one variation, which means it
+// does not vary, hence why the method is called that.
+func (sn Snake) Add(data ...byte) Snake {
+	return sn.AddVar(data)
+}
+
+// Check determines if the data satisfies the snake.
+func (sn Snake) Check(data []byte) (ok bool, n int) {
+	left := data
+	variations := map[int] []byte { }
+	for _, sector := range sn {
+		clear(variations)
+		for key, variation := range sector {
+			variations[key] = variation
+		}
+		for len(variations) > 0 {
+			found := false
+			for key, variation := range variations {
+				if len(left) < len(variation) { continue }
+				if !slices.Equal(left[:len(variation)], variation) { continue }
+				n += len(variation)
+				left = data[n:]
+				delete(variations, key)
+				found = true
+			}
+			if !found { return false, n }
+		}
+	}
+	if n < len(data) {
+		return false, n
+	}
+	return true, n
+}
+
+// Flatten returns the snake flattened to a byte array. The result of this
+// function always satisfies the snake.
+func (sn Snake) Flatten() []byte {
+	flat := []byte { }
+	for _, sector := range sn {
+		for _, variation := range sector {
+			flat = append(flat, variation...)
+		}
+	}
+	return flat
+}
+
+func (sn Snake) String() string {
+	if len(sn) == 0 || len(sn[0]) == 0 || len(sn[0][0]) == 0 {
+		return "EMPTY"
+	}
+
+	out := strings.Builder { }
+	for index, sector := range sn {
+		if index > 0 { out.WriteString(" : ") }
+		out.WriteRune('[')
+		for index, variation := range sector {
+			if index > 0 { out.WriteString(" / ") }
+			for _, byt := range variation {
+				fmt.Fprintf(&out, "%02x", byt)
+			}
+		}
+		out.WriteRune(']')
+	}
+	return out.String()
+}
+
+// HexBytes formats bytes into a hexadecimal string.
+func HexBytes(data []byte) string {
+	if len(data) == 0 { return "EMPTY" }
+	out := strings.Builder { }
+	for _, byt := range data {
+		fmt.Fprintf(&out, "%02x", byt)
+	}
+	return out.String()
+}
+
+// Describe returns a string representing the type and data of the given value.
+func Describe(value any) string {
+	desc := describer { }
+	desc.describe(reflect.ValueOf(value))
+	return desc.String()
+}
+
+type describer struct {
+	strings.Builder
+	indent int
+}
+
+func (this *describer) describe(value reflect.Value) {
+	if !value.IsValid() {
+		this.printf("<invalid>")
+		return
+	}
+	value = reflect.ValueOf(value.Interface())
+	if !value.IsValid() {
+		this.printf("<invalid>")
+		return
+	}
+	switch value.Kind() {
+	case reflect.Array, reflect.Slice:
+		this.printf("[\n")
+		this.indent += 1
+		for index := 0; index < value.Len(); index ++ {
+			this.iprintf("")
+			this.describe(value.Index(index))
+			this.iprintf("\n")
+		}
+		this.indent -= 1
+		this.iprintf("]")
+	case reflect.Struct:
+		this.printf("struct {\n")
+		this.indent += 1
+		typ := value.Type()
+		for index := range typ.NumField() {
+			indexBuffer := [1]int { index }
+			field := typ.Field(index)
+			this.iprintf("%s: ", field.Name)
+			for _, char := range field.Name {
+				if unicode.IsUpper(char) {
+					this.describe(value.FieldByIndex(indexBuffer[:]))
+				} else {
+					this.printf("<private>")
+				}
+				break
+			}
+			this.iprintf("\n")
+		}
+		this.indent -= 1
+		this.iprintf("}")
+	case reflect.Map:
+		this.printf("map {\n")
+		this.indent += 1
+		iter := value.MapRange()
+		for iter.Next() {
+			this.iprintf("")
+			this.describe(iter.Key())
+			this.printf(": ")
+			this.describe(iter.Value())
+			this.iprintf("\n")
+		}
+		this.indent -= 1
+		this.iprintf("}")
+	case reflect.Pointer:
+		this.printf("& ")
+		this.describe(value.Elem())
+	default:
+		this.printf("<%v %v>", value.Type(), value.Interface())
+	}
+}
+
+func (this *describer) printf(format string, v ...any) {
+	fmt.Fprintf(this, format, v...)
+}
+
+func (this *describer) iprintf(format string, v ...any) {
+	fmt.Fprintf(this, strings.Repeat("\t", this.indent) + format, v...)
+}

internal/testutil/testutil_test.go

@@ -0,0 +1,66 @@
+package testutil
+
+import "testing"
+
+func TestSnakeA(test *testing.T) {
+	snake := S(1, 6).AddVar(
+		[]byte { 1 },
+		[]byte { 2 },
+		[]byte { 3 },
+		[]byte { 4 },
+		[]byte { 5 },
+	).Add(9)
+
+	test.Log(snake)
+
+	ok, n := snake.Check([]byte { 1, 6, 1, 2, 3, 4, 5, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 5, 4, 3, 2, 1, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 3, 1, 4, 2, 5, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	
+	ok, n = snake.Check([]byte { 1, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 1, 2, 3, 4, 5, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 0, 2, 3, 4, 5, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 7, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 7, 3, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 7, 3, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 1, 2, 3, 4, 5, 9, 10})
+	if ok { test.Fatal("false positive:", n) }
+}
+
+func TestSnakeB(test *testing.T) {
+	snake := S(1, 6).AddVar(
+		[]byte { 1 },
+		[]byte { 2 },
+	).Add(9).AddVar(
+		[]byte { 3, 2 },
+		[]byte { 0 },
+		[]byte { 1, 1, 2, 3 },
+	)
+
+	test.Log(snake)
+
+	ok, n := snake.Check([]byte { 1, 6, 1, 2, 9, 3, 2, 0, 1, 1, 2, 3})
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 2, 1, 9, 0, 1, 1, 2, 3, 3, 2})
+	if !ok { test.Fatal("false negative:", n) }
+	
+	ok, n = snake.Check([]byte { 1, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 1, 2, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 9, 3, 2, 0, 1, 1, 2, 3})
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 2, 9, 0, 1, 1, 2, 3, 3, 2})
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = snake.Check([]byte { 1, 6, 1, 2, 9, 3, 2, 1, 1, 2, 3})
+	if ok { test.Fatal("false positive:", n) }
+}

listen.go

@@ -1,9 +1,8 @@
 package hopp
 
 import "net"
-import "context"
+import "errors"
 import "crypto/tls"
-import "github.com/quic-go/quic-go"
 
 // Listener is an object which listens for incoming HOPP connections.
 type Listener interface {
@@ -17,7 +16,8 @@ type Listener interface {
 }
 
 // Listen listens for incoming HOPP connections. The network must be one of
-// "quic", "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix".
+// "quic", "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, quic is
+// not supported.
 func Listen(network, address string) (Listener, error) {
 	switch network {
 	case "quic", "quic4", "quic6": return ListenQUIC(network, address, nil)
@@ -30,19 +30,8 @@ func Listen(network, address string) (Listener, error) {
 // The network must be one of "quic", "quic4", (IPv4-only) or "quic6"
 // (IPv6-only).
 func ListenQUIC(network, address string, tlsConf *tls.Config) (Listener, error) {
-	tlsConf   = tlsConfig(tlsConf)
-	quicConf := quicConfig()
-	udpNetwork, err := quicNetworkToUDPNetwork(network)
-	if err != nil { return nil, err }
-	addr, err := net.ResolveUDPAddr(udpNetwork, address)
-	if err != nil { return nil, err }
-	udpListener, err := net.ListenUDP(udpNetwork, addr)
-	if err != nil { return nil, err }
-	quicListener, err := quic.Listen(udpListener, tlsConf, quicConf)
-	if err != nil { return nil, err }
-	return &listenerQUIC {
-		underlying: quicListener,
-	}, nil
+	// tlsConf   = tlsConfig(tlsConf)
+	return nil, errors.New("quic is not yet implemented")
 }
 
 // ListenUnix listens for incoming HOPP connections using a Unix domain socket
@@ -58,24 +47,6 @@ func ListenUnix(network, address string) (Listener, error) {
 	}, nil
 }
 
-type listenerQUIC struct {
-	underlying *quic.Listener
-}
-
-func (this *listenerQUIC) Accept() (Conn, error) {
-	conn, err := this.underlying.Accept(context.Background())
-	if err != nil { return nil, err }
-	return AdaptB(quicMultiConn { underlying: conn }), nil
-}
-
-func (this *listenerQUIC) Close() error {
-	return this.underlying.Close()
-}
-
-func (this *listenerQUIC) Addr() net.Addr {
-	return this.underlying.Addr()
-}
-
 type listenerUnix struct {
 	underlying *net.UnixListener
 }

message.go

@@ -1,52 +0,0 @@
-package hopp
-
-import "fmt"
-import "encoding"
-import "git.tebibyte.media/sashakoshka/hopp/tape"
-
-// Message is any object that can be sent or received over a HOPP connection.
-type Message interface {
-	// Method returns the method number of the message. This must be unique
-	// within the protocol, and should not change between calls.
-	Method() uint16
-	encoding.BinaryMarshaler
-	encoding.BinaryUnmarshaler
-}
-
-var _ Message = new(MessageData)
-
-// MessageData represents a message that organizes its data into table pairs. It
-// can be used to alter a protocol at runtime, transmit data with arbitrary
-// keys, etc. Bear in mind that is less performant than generating code because
-// it has to make extra memory allocations and such.
-type MessageData struct {
-	// Methd holds the method number. This should only be set once.
-	Methd uint16
-	// Pairs maps tags to values.
-	Pairs map[uint16] []byte
-}
-
-// Method returns the message's method field.
-func (this *MessageData) Method() uint16 {
-	return this.Methd
-}
-
-// MarshalBinary implements the [encoding.BinaryMarshaler] interface. The
-// message is encoded using TAPE (Table Pair Encoding).
-func (this *MessageData) MarshalBinary() ([]byte, error) {
-	buffer, err := tape.EncodePairs(this.Pairs)
-	if err != nil { return nil, fmt.Errorf("marshaling MessageData: %w", err) }
-	return buffer, nil
-}
-
-// UnmarshalBinary implements the [encoding.BinaryUnmarshaler] interface. The
-// message is decoded using TAPE (Table Pair Encoding).
-func (this *MessageData) UnmarshalBinary(buffer []byte) error {
-	this.Pairs = make(map[uint16] []byte)
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return fmt.Errorf("unmarshaling MessageData: %w", err) }
-	for key, value := range pairs {
-		this.Pairs[key] = value
-	}
-	return nil
-}

metadapta.go

@@ -1,11 +1,12 @@
 package hopp
 
 import "io"
+import "os"
 import "fmt"
 import "net"
 import "sync"
+import "time"
 import "sync/atomic"
-import "git.tebibyte.media/sashakoshka/hopp/tape"
 import "git.tebibyte.media/sashakoshka/go-util/sync"
 
 // TODO investigate why 30 never reaches the server, causing it to wait for ever
@@ -109,6 +110,10 @@ func (this *a) AcceptTrans() (Trans, error) {
 	}
 }
 
+func (this *a) SetDeadline(t time.Time) error {
+	return this.underlying.SetDeadline(t)
+}
+
 func (this *a) SetSizeLimit(limit int64) {
 	this.sizeLimit = limit
 }
@@ -213,6 +218,10 @@ type transA struct {
 	currentWriter io.Closer
 	writeBuffer   []byte
 	closed        atomic.Bool
+	closeErr      error
+	
+	deadline      *time.Timer
+	deadlineLock  sync.Mutex
 }
 
 func (this *transA) Close() error {
@@ -222,6 +231,11 @@ func (this *transA) Close() error {
 	return err
 }
 
+func (this *transA) closeWithError(err error) error {
+	this.closeErr = err
+	return this.Close()
+}
+
 func (this *transA) closeDontUnlist() (err error) {
 	// MUST be goroutine safe
 	this.incoming.Close()
@@ -270,9 +284,9 @@ func (this *transA) Receive() (method uint16, data []byte, err error) {
 }
 
 func (this *transA) ReceiveReader() (uint16, io.Reader, error) {
-	// if the transaction has been closed, return an io.EOF
-	if this.closed.Load() {
-		return 0, nil, io.EOF
+	// if the transaction has been closed, return an appropriate error.
+	if err := this.errIfClosed(); err != nil {
+		return 0, nil, err
 	}
 
 	// drain previous reader if necessary
@@ -290,6 +304,54 @@ func (this *transA) ReceiveReader() (uint16, io.Reader, error) {
 	return method, reader, nil
 }
 
+func (this *transA) SetDeadline(t time.Time) error {
+	this.deadlineLock.Lock()
+	defer this.deadlineLock.Unlock()
+
+	if t == (time.Time { }) {
+		if this.deadline != nil {
+			this.deadline.Stop()
+		}
+		return nil
+	}
+	
+	until := time.Until(t)
+	if this.deadline == nil {
+		this.deadline.Reset(until)
+		return nil
+	}
+	this.deadline = time.AfterFunc(until, func () {
+		this.closeWithError(os.ErrDeadlineExceeded)
+	})
+	return nil
+}
+
+// TODO
+// func (this *transA) SetReadDeadline(t time.Time) error {
+// 	// TODO
+// }
+// 
+// func (this *transA) SetWriteDeadline(t time.Time) error {
+// 	// TODO
+// }
+
+func (this *transA) errIfClosed() error {
+	if !this.closed.Load() {
+		return nil
+	}
+	return this.bestErr()
+}
+
+func (this *transA) bestErr() error {
+	if this.parent.err != nil {
+		return this.parent.err
+	}
+	if this.closeErr != nil {
+		return this.closeErr
+	}
+	return io.EOF
+}
+
 type readerA struct {
 	parent   *transA
 	leftover []byte
@@ -320,11 +382,7 @@ func (this *readerA) pull() (uint16, error) {
 	// close and return error on failure
 	this.eof = true
 	this.parent.Close()
-	if this.parent.parent.err == nil {
-		return 0, fmt.Errorf("could not receive message: %w", io.EOF)
-	} else {
-		return 0, this.parent.parent.err
-	}
+	return 0, fmt.Errorf("could not receive message: %w", this.parent.bestErr())
 }
 
 func (this *readerA) Read(buffer []byte) (int, error) {
@@ -406,9 +464,9 @@ func encodeMessageA(
 		return ErrPayloadTooLarge
 	}
 	buffer := make([]byte, 18 + len(data))
-	tape.EncodeI64(buffer[:8], trans)
-	tape.EncodeI16(buffer[8:10], method)
-	tape.EncodeI64(buffer[10:18], uint64(len(data)))
+	encodeI64(buffer[:8], trans)
+	encodeI16(buffer[8:10], method)
+	encodeI64(buffer[10:18], uint64(len(data)))
 	copy(buffer[18:], data)
 	_, err := writer.Write(buffer)
 	return err
@@ -427,11 +485,11 @@ func decodeMessageA(
 	headerBuffer := [18]byte { }
 	_, err = io.ReadFull(reader, headerBuffer[:])
 	if err != nil { return 0, 0, false, nil, err }
-	transID, err = tape.DecodeI64[int64](headerBuffer[:8])
+	transID, err = decodeI64[int64](headerBuffer[:8])
 	if err != nil { return 0, 0, false, nil, err }
-	method, err = tape.DecodeI16[uint16](headerBuffer[8:10])
+	method, err = decodeI16[uint16](headerBuffer[8:10])
 	if err != nil { return 0, 0, false, nil, err }
-	size, err := tape.DecodeI64[uint64](headerBuffer[10:18])
+	size, err := decodeI64[uint64](headerBuffer[10:18])
 	if err != nil { return 0, 0, false, nil, err }
 	chunked, size = splitCCBSize(size)
 	if size > uint64(sizeLimit) {

metadaptb.go

@@ -2,10 +2,10 @@ package hopp
 
 import "io"
 import "net"
+import "time"
 import "bytes"
 import "errors"
 import "context"
-import "git.tebibyte.media/sashakoshka/hopp/tape"
 
 // B implements METADAPT-B over a multiplexed stream-oriented transport such as
 // QUIC.
@@ -51,6 +51,10 @@ func (this *b) SetSizeLimit(limit int64) {
 	this.sizeLimit = limit
 }
 
+func (this *b) SetDeadline(t time.Time) error {
+	return this.underlying.SetDeadline(t)
+}
+
 func (this *b) newTrans(underlying Stream) *transB {
 	return &transB {
 		sizeLimit: this.sizeLimit,
@@ -125,6 +129,10 @@ func (this *transB) receiveReader() (uint16, int64, io.Reader, error) {
 	return method, size, data, nil
 }
 
+func (this *transB) SetDeadline(t time.Time) error {
+	return this.underlying.SetDeadline(t)
+}
+
 type writerB struct {
 	parent *transB
 	buffer bytes.Buffer
@@ -150,12 +158,16 @@ type MultiConn interface {
 	AcceptStream(context.Context) (Stream, error)
 	// OpenStream opens a new stream.
 	OpenStream() (Stream, error)
+	// See the documentation for [net.Conn.SetDeadline].
+	SetDeadline(time.Time) error
 }
 
 // Stream represents a single stream returned by a [MultiConn].
 type Stream interface {
 	// See documentation for [net.Conn].
 	io.ReadWriteCloser
+	// See the documentation for [net.Conn.SetDeadline].
+	SetDeadline(time.Time) error
 	// ID returns the stream ID
 	ID() int64
 }
@@ -165,8 +177,8 @@ func encodeMessageB(writer io.Writer, sizeLimit int64, method uint16, data []byt
 		return ErrPayloadTooLarge
 	}
 	buffer := make([]byte, 10 + len(data))
-	tape.EncodeI16(buffer[:2], method)
-	tape.EncodeI64(buffer[2:10], uint64(len(data)))
+	encodeI16(buffer[:2], method)
+	encodeI64(buffer[2:10], uint64(len(data)))
 	copy(buffer[10:], data)
 	_, err := writer.Write(buffer)
 	return err
@@ -187,9 +199,9 @@ func decodeMessageB(
 		if errors.Is(err, io.EOF) { return 0, 0, nil, io.ErrUnexpectedEOF }
 		return 0, 0, nil, err
 	}
-	method, err = tape.DecodeI16[uint16](headerBuffer[:2])
+	method, err = decodeI16[uint16](headerBuffer[:2])
 	if err != nil { return 0, 0, nil, err }
-	length, err := tape.DecodeI64[uint64](headerBuffer[2:10])
+	length, err := decodeI64[uint64](headerBuffer[2:10])
 	if err != nil { return 0, 0, nil, err }
 	if length > uint64(sizeLimit) {
 		return 0, 0, nil, ErrPayloadTooLarge

quicwrap.go

@@ -1,54 +0,0 @@
-package hopp
-
-import "net"
-import "context"
-import "github.com/quic-go/quic-go"
-
-var _ MultiConn = quicMultiConn { }
-type quicMultiConn struct {
-	underlying quic.Connection
-}
-
-func (conn quicMultiConn) Close() error {
-	return conn.underlying.CloseWithError(0, "good bye")
-}
-
-func (conn quicMultiConn) LocalAddr() net.Addr {
-	return conn.underlying.LocalAddr()
-}
-
-func (conn quicMultiConn) RemoteAddr() net.Addr {
-	return conn.underlying.RemoteAddr()
-}
-
-func (conn quicMultiConn) AcceptStream(ctx context.Context) (Stream, error) {
-	strea, err := conn.underlying.AcceptStream(ctx)
-	if err != nil { return nil, err }
-	return quicStream { underlying: strea }, nil
-}
-
-func (conn quicMultiConn) OpenStream() (Stream, error) {
-	strea, err := conn.underlying.OpenStream()
-	if err != nil { return nil, err }
-	return quicStream { underlying: strea }, nil
-}
-
-type quicStream struct {
-	underlying quic.Stream
-}
-
-func (strea quicStream) Read(buffer []byte) (n int, err error) {
-	return strea.underlying.Read(buffer)
-}
-
-func (strea quicStream) Write(buffer []byte) (n int, err error) {
-	return strea.underlying.Read(buffer)
-}
-
-func (strea quicStream) Close() error {
-	return strea.underlying.Close()
-}
-
-func (strea quicStream) ID() int64 {
-	return int64(strea.underlying.StreamID())
-}

tape/decode.go

@@ -0,0 +1,192 @@
+package tape
+
+import "io"
+import "math"
+import "bufio"
+
+// Decodable is any type that can decode itself from a decoder.
+type Decodable interface {
+	// Decode reads data from decoder, replacing the data of the object. It
+	// returns the amount of bytes written, and an error if the write
+	// stopped early.
+	Decode(decoder *Decoder) (n int, err error)
+}
+
+// Decoder decodes data from an [io.Reader].
+type Decoder struct {
+	bufio.Reader
+}
+
+// NewDecoder creates a new decoder that reads from reader.
+func NewDecoder(reader io.Reader) *Decoder {
+	decoder := &Decoder { }
+	decoder.Reader.Reset(reader)
+	return decoder
+}
+
+// ReadFull calls [io.ReadFull] on the reader.
+func (this *Decoder) ReadFull(buffer []byte) (n int, err error) {
+	return io.ReadFull(this, buffer)
+}
+
+// ReadInt8 decodes an 8-bit signed integer from the input reader.
+func (this *Decoder) ReadInt8() (value int8, n int, err error) {
+	uncasted, n, err := this.ReadUint8()
+	return int8(uncasted), n, err
+}
+
+// ReadUint8 decodes an 8-bit unsigned integer from the input reader.
+func (this *Decoder) ReadUint8() (value uint8, n int, err error) {
+	buffer := [1]byte { }
+	n, err = this.ReadFull(buffer[:])
+	return uint8(buffer[0]), n, err
+}
+
+// ReadInt16 decodes an 16-bit signed integer from the input reader.
+func (this *Decoder) ReadInt16() (value int16, n int, err error) {
+	uncasted, n, err := this.ReadUint16()
+	return int16(uncasted), n, err
+}
+
+// ReadUint16 decodes an 16-bit unsigned integer from the input reader.
+func (this *Decoder) ReadUint16() (value uint16, n int, err error) {
+	buffer := [2]byte { }
+	n, err = this.ReadFull(buffer[:])
+	return uint16(buffer[0]) << 8 |
+		uint16(buffer[1]), n, err
+}
+
+// ReadInt32 decodes an 32-bit signed integer from the input reader.
+func (this *Decoder) ReadInt32() (value int32, n int, err error) {
+	uncasted, n, err := this.ReadUint32()
+	return int32(uncasted), n, err
+}
+
+// ReadUint32 decodes an 32-bit unsigned integer from the input reader.
+func (this *Decoder) ReadUint32() (value uint32, n int, err error) {
+	buffer := [4]byte { }
+	n, err = this.ReadFull(buffer[:])
+	return uint32(buffer[0]) << 24 |
+		uint32(buffer[1]) << 16 |
+		uint32(buffer[2]) << 8 |
+		uint32(buffer[3]), n, err
+}
+
+// ReadInt64 decodes an 64-bit signed integer from the input reader.
+func (this *Decoder) ReadInt64() (value int64, n int, err error) {
+	uncasted, n, err := this.ReadUint64()
+	return int64(uncasted), n, err
+}
+
+// ReadUint64 decodes an 64-bit unsigned integer from the input reader.
+func (this *Decoder) ReadUint64() (value uint64, n int, err error) {
+	buffer := [8]byte { }
+	n, err = this.ReadFull(buffer[:])
+	return uint64(buffer[0]) << 56 |
+		uint64(buffer[1]) << 48 |
+		uint64(buffer[2]) << 40 |
+		uint64(buffer[3]) << 32 |
+		uint64(buffer[4]) << 24 |
+		uint64(buffer[5]) << 16 |
+		uint64(buffer[6]) << 8 |
+		uint64(buffer[7]), n, err
+}
+
+// ReadIntN decodes an N-byte signed integer from the input reader.
+func (this *Decoder) ReadIntN(bytes int) (value int64, n int, err error) {
+	uncasted, n, err := this.ReadUintN(bytes)
+	return int64(uncasted), n, err
+}
+
+// ReadUintN decodes an N-byte unsigned integer from the input reader.
+func (this *Decoder) ReadUintN(bytes int) (value uint64, n int, err error) {
+	// TODO: don't make multiple read calls (without allocating)
+	buffer := [1]byte { }
+	for bytesLeft := bytes; bytesLeft > 0; bytesLeft -- {
+		nn, err := this.ReadFull(buffer[:])
+		n += nn; if err != nil { return 0, n, err }
+		value |= uint64(buffer[0]) << ((bytesLeft - 1) * 8)
+	}
+	// *read* integers too big, but don't return them.
+	if bytes > 8 { value = 0 }
+	return value, n, nil
+}
+
+// ReadFloat16 decodes a 16-bit floating point value from the input reader.
+func (this *Decoder) ReadFloat16() (value float32, n int, err error) {
+	bits, nn, err := this.ReadUint16()
+	n += nn; if err != nil { return 0, n, err }
+	return math.Float32frombits(f16bitsToF32bits(bits)), n, nil
+}
+
+// ReadFloat32 decldes a 32-bit floating point value from the input reader.
+func (this *Decoder) ReadFloat32() (value float32, n int, err error) {
+	bits, nn, err := this.ReadUint32()
+	n += nn; if err != nil { return 0, n, err }
+	return math.Float32frombits(bits), n, nil
+}
+
+// ReadFloat64 decldes a 64-bit floating point value from the input reader.
+func (this *Decoder) ReadFloat64() (value float64, n int, err error) {
+	bits, nn, err := this.ReadUint64()
+	n += nn; if err != nil { return 0, n, err }
+	return math.Float64frombits(bits), n, nil
+}
+
+// ReadTag decodes a [Tag] from the input reader.
+func (this *Decoder) ReadTag() (value Tag, n int, err error) {
+	uncasted, nn, err := this.ReadUint8()
+	n += nn; if err != nil { return 0, n, err }
+	return Tag(uncasted), n, nil
+}
+
+// f16bitsToF32bits returns uint32 (float32 bits) converted from specified uint16.
+// Taken from https://github.com/x448/float16/blob/v0.8.4/float16
+//
+// MIT License
+// 
+// Copyright (c) 2019 Montgomery Edwards⁴⁴⁸ and Faye Amacker
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+func f16bitsToF32bits(in uint16) uint32 {
+	// All 65536 conversions with this were confirmed to be correct
+	// by Montgomery Edwards⁴⁴⁸ (github.com/x448).
+	
+	sign := uint32(in&0x8000) << 16 // sign for 32-bit
+	exp := uint32(in&0x7c00) >> 10  // exponenent for 16-bit
+	coef := uint32(in&0x03ff) << 13 // significand for 32-bit
+
+	if exp == 0x1f {
+		if coef == 0 {
+			// infinity
+			return sign | 0x7f800000 | coef
+		}
+		// NaN
+		return sign | 0x7fc00000 | coef
+	}
+
+	if exp == 0 {
+		if coef == 0 {
+			// zero
+			return sign
+		}
+
+		// normalize subnormal numbers
+		exp++
+		for coef&0x7f800000 == 0 {
+			coef <<= 1
+			exp--
+		}
+		coef &= 0x007fffff
+	}
+
+	return sign | ((exp + (0x7f - 0xf)) << 23) | coef
+}

tape/dynamic.go

@@ -0,0 +1,626 @@
+package tape
+
+// dont smoke reflection, kids!!!!!!!!!
+// totally reflectric, reflectrified, etc. this is probably souper slow but
+// certainly no slower than the built in json encoder i'd imagine.
+// TODO: add support for struct tags: `tape:"0000"`, tape:"0001"` so they can get
+// transformed into tables with a defined schema
+
+// TODO: test all of these smaller functions individually
+
+// For an explanation as to why this package always treats LBA/SBA as strings,
+// refer to https://go.dev/blog/strings:
+// 
+//   It’s important to state right up front that a string holds arbitrary
+//   bytes. It is not required to hold Unicode text, UTF-8 text, or any other
+//   predefined format. As far as the content of a string is concerned, it is
+//   exactly equivalent to a slice of bytes.
+//
+// Arbitrary byte slices and blobs won't be as common of a use case as text
+// data, and if you need that anyway you can just cast it to a byte slice.
+
+import "fmt"
+import "reflect"
+
+var dummyMap map[uint16] any
+var dummyBuffer []byte
+
+type errCantAssign string
+func (err errCantAssign) Error() string {
+	return string(err)
+}
+func errCantAssignf(format string, v ...any) errCantAssign {
+	return errCantAssign(fmt.Sprintf(format, v...))
+}
+
+// EncodeAny encodes an "any" value. Returns an error if the underlying type is
+// unsupported. Supported types are:
+//
+//   - int
+//   - int<N>
+//   - uint
+//   - uint<N>
+//   - string
+//   - []<supported type>
+//   - map[uint16]<supported type>
+func EncodeAny(encoder *Encoder, value any, tag Tag) (n int, err error) {
+	// primitives
+	reflectValue := reflect.ValueOf(value)
+	switch reflectValue.Kind() {
+	case reflect.Int:     return encoder.WriteInt32(int32(reflectValue.Int()))
+	case reflect.Uint:    return encoder.WriteUint32(uint32(reflectValue.Uint()))
+	case reflect.Int8:    return encoder.WriteInt8(int8(reflectValue.Int()))
+	case reflect.Uint8:   return encoder.WriteUint8(uint8(reflectValue.Uint()))
+	case reflect.Int16:   return encoder.WriteInt16(int16(reflectValue.Int()))
+	case reflect.Uint16:  return encoder.WriteUint16(uint16(reflectValue.Uint()))
+	case reflect.Int32:   return encoder.WriteInt32(int32(reflectValue.Int()))
+	case reflect.Uint32:  return encoder.WriteUint32(uint32(reflectValue.Uint()))
+	case reflect.Int64:   return encoder.WriteInt64(int64(reflectValue.Int()))
+	case reflect.Uint64:  return encoder.WriteUint64(uint64(reflectValue.Uint()))
+	case reflect.Float32: return encoder.WriteFloat32(float32(reflectValue.Float()))
+	case reflect.Float64: return encoder.WriteFloat64(float64(reflectValue.Float()))
+	case reflect.Bool:    return // SI has no payload
+	case reflect.String:
+		if reflectValue.Len() > MaxStructureLength {
+			return 0, ErrTooLong
+		}
+		return EncodeAny(encoder, []byte(reflectValue.String()), tag)
+	}
+	if reflectValue.CanConvert(reflect.TypeOf(dummyBuffer)) {
+		if reflectValue.Len() > MaxStructureLength {
+			return 0, ErrTooLong
+		}
+		if tag.Is(LBA) {
+			nn, err := encoder.WriteUintN(uint64(reflectValue.Len()), tag.CN() + 1)
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err := encoder.Write(reflectValue.Bytes())
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+
+	// aggregates
+	reflectType := reflect.TypeOf(value)
+	switch reflectType.Kind() {
+	case reflect.Slice:
+		return encodeAnySlice(encoder, value, tag)
+	// case reflect.Array:
+		// TODO: we can encode arrays. but can we decode into them?
+		// that's the fucken question. maybe we just do the first
+		// return encodeAnySlice(encoder, reflect.ValueOf(value).Slice(0, reflectType.Len()).Interface(), tag)
+	case reflect.Map:
+		if reflectValue.Len() > MaxStructureLength {
+			return 0, ErrTooLong
+		}
+		if reflectType.Key() == reflect.TypeOf(uint16(0)) {
+			return encodeAnyMap(encoder, value, tag)
+		}
+		return n, fmt.Errorf("cannot encode map key %T, key must be uint16", value)
+	}
+	return n, fmt.Errorf("cannot encode type %T", value)
+}
+
+// DecodeAnyInto decodes data and places it into destination, which must be a
+// pointer to a supported type. See [EncodeAny] for a list of supported types.
+// The head of the decoder must be at the start of the payload.
+func DecodeAnyInto(decoder *Decoder, destination any, tag Tag) (n int, err error) {
+	reflectDestination := reflect.ValueOf(destination)
+	if reflectDestination.Kind() != reflect.Pointer {
+		return n, fmt.Errorf("expected pointer destination, not %v", destination)
+	}
+	return decodeAny(decoder, reflectDestination.Elem(), tag)
+}
+
+// DecodeAny is like [DecodeAnyInto], but it automatically creates the
+// destination from the tag and data. The head of the decoder must be at the
+// start of the payload.
+func DecodeAny(decoder *Decoder, tag Tag) (value any, n int, err error) {
+	destination, err := skeletonPointer(decoder, tag)
+	if err != nil { return nil, n, err }
+	nn, err := decodeAny(decoder, destination.Elem(), tag)
+	n += nn; if err != nil { return nil, n, err }
+	return destination.Elem().Interface(), n, err
+}
+
+// unknownSlicePlaceholder is inserted by skeletonValue and informs the program
+// that the destination for the slice needs to be generated based on the item
+// tag in the OTA.
+type unknownSlicePlaceholder struct { }
+var unknownSlicePlaceholderType = reflect.TypeOf(unknownSlicePlaceholder { })
+
+// decodeAny is internal to [DecodeAny]. It takes in an addressable
+// [reflect.Value] as the destination. If the decoded value cannot fit in the
+// destination, it skims over the payload, leaves the destination empty, and
+// returns without an error. The head of the decoder must be at the start of the
+// payload.
+func decodeAny(decoder *Decoder, destination reflect.Value, tag Tag) (n int, err error) {
+	n, err = decodeAnyOrError(decoder, destination, tag)
+	if _, ok := err.(errCantAssign); ok {
+		if n > 0 { panic(fmt.Sprintf("decodeAnyOrError decoded more than it should: %d", n)) }
+		nn, err := Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	return n, err
+}
+
+// decodeAnyOrError is internal to [decodeAny]. It takes in an addressable
+// [reflect.Value] as the destination. If the decoded value cannot fit in the
+// destination, it decodes nothing and returns an error of type errCantAssign,
+// except for the case of a mismatched OTA element tag, wherein it will skim
+// over the rest of the payload, leave the destination empty, and return without
+// an error. The head of the decoder must be at the start of the payload.
+func decodeAnyOrError(decoder *Decoder, destination reflect.Value, tag Tag) (n int, err error) {
+	err = canSet(destination.Type(), tag)
+	if err != nil { return n, err }
+	
+	switch tag.WithoutCN() {
+	case SI:
+		// SI: (none)
+		setUint(destination, uint64(tag.CN()), 1)
+	case LI:
+		// LI: <value: IntN>
+		nn, err := decodeAndSetUint(decoder, destination, tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+	case LSI:
+		// LSI: <value: IntN>
+		nn, err := decodeAndSetInt(decoder, destination, tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+	case FP:
+		// FP: <value: FloatN>
+		nn, err := decodeAndSetFloat(decoder, destination, tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+	case SBA:
+		// SBA: <data: U8>*
+		length := tag.CN()
+		if length > MaxStructureLength {
+			return 0, ErrTooLong
+		}
+		buffer := make([]byte, length)
+		nn, err := decoder.Read(buffer)
+		n += nn; if err != nil { return n, err }
+		setString(destination, string(buffer))
+	case LBA:
+		// LBA: <length: UN> <data: U8>*
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		if length > uint64(MaxStructureLength) {
+			return 0, ErrTooLong
+		}
+		buffer := make([]byte, length)
+		nn, err = decoder.Read(buffer)
+		n += nn; if err != nil { return n, err }
+		setString(destination, string(buffer))
+	case OTA:
+		// OTA: <length: UN> <elementTag: tape.Tag> <values>*
+		oldDestination := destination
+		if isTypeAny(destination.Type()) {
+			// need a skeleton value if we are assigning to any.
+			value, err := skeletonValue(decoder, tag)
+			if err != nil { return n, err }
+			destination = value
+		}
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		if length > uint64(MaxStructureLength) {
+			return 0, ErrTooLong
+		}
+		lengthCast, err := Uint64ToIntSafe(length)
+		if err != nil { return n, err }
+		oneTag, nn, err := decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		if destination.Cap() < lengthCast {
+			destination.Grow(lengthCast - destination.Cap())
+		}
+		// skip the rest of the array if the one tag doesn't
+		// match up with the destination
+		err = canSet(destination.Type().Elem(), oneTag)
+		if _, ok := err.(errCantAssign); ok {
+			for _ = range length {
+				nn, err := Skim(decoder, oneTag)
+				n += nn; if err != nil { return n, err }
+			}
+			break
+		}
+		if err != nil { return n, err }
+		destination.SetLen(lengthCast)
+		for index := range length {
+			nn, err := decodeAny(decoder, destination.Index(int(index)), oneTag)
+			n += nn
+			if _, ok := err.(errCantAssign); ok {
+				continue
+			} else if err != nil {
+				return n, err
+			}
+		}
+		oldDestination.Set(destination)
+	case KTV:
+		// KTV: <length: UN> (<key: U16> <tag: Tag> <value>)*
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		if length > uint64(MaxStructureLength) {
+			return 0, ErrTooLong
+		}
+		lengthCast, err := Uint64ToIntSafe(length)
+		if err != nil { return n, err }
+
+		// im fucking so done dude. im so fucking done. this was
+		// supposed to only run when we need it but i guess it runs all
+		// the time, because when we get a map destination (a valid,
+		// allocated one) we break apart on SetMapIndex because of a nil
+		// map. yeah thats right. a fucking nil map panic. on the map we
+		// just allocated. but running this unconditionally (whether or
+		// not we receive an empty any value) actually makes it fucking
+		// work. go figure().
+		//
+		// (the map allocation functionality in skeletonPointer was
+		// removed after this comment was written)
+		value := reflect.MakeMapWithSize(reflect.TypeOf(dummyMap), lengthCast)
+		destination.Set(value)
+		destination = value
+		
+		destination.Clear()
+		for _ = range lengthCast {
+			key, nn, err := decoder.ReadUint16()
+			n += nn; if err != nil { return n, err }
+			itemTag, nn, err := decoder.ReadTag()
+			n += nn; if err != nil { return n, err }
+			value, err := skeletonPointer(decoder, itemTag)
+			if err != nil { return n, err }
+			nn, err = decodeAny(decoder, value.Elem(), itemTag)
+			n += nn; if err != nil { return n, err }
+			destination.SetMapIndex(reflect.ValueOf(key), value.Elem())
+		}
+	default:
+		return n, fmt.Errorf("unknown TN %d", tag.TN())
+	}
+	return n, nil
+}
+
+// TagAny returns the correct tag for an "any" value. Returns an error if the
+// underlying type is unsupported. See [EncodeAny] for a list of supported
+// types.
+func TagAny(value any) (Tag, error) {
+	return tagAny(reflect.ValueOf(value))
+}
+
+func tagAny(reflectValue reflect.Value) (Tag, error) {
+	// primitives
+	switch reflectValue.Kind() {
+	case reflect.Int:     return LSI.WithCN(3), nil
+	case reflect.Int8:    return LSI.WithCN(0), nil
+	case reflect.Int16:   return LSI.WithCN(1), nil
+	case reflect.Int32:   return LSI.WithCN(3), nil
+	case reflect.Int64:   return LSI.WithCN(7), nil
+	case reflect.Uint:    return LI.WithCN(3), nil
+	case reflect.Uint8:   return LI.WithCN(0), nil
+	case reflect.Uint16:  return LI.WithCN(1), nil
+	case reflect.Uint32:  return LI.WithCN(3), nil
+	case reflect.Uint64:  return LI.WithCN(7), nil
+	case reflect.Float32: return FP.WithCN(3), nil
+	case reflect.Float64: return FP.WithCN(7), nil
+	case reflect.Bool:
+		if reflectValue.Bool() {
+			return SI.WithCN(1), nil
+		} else {
+			return SI.WithCN(0), nil
+		}
+	case reflect.String:  return bufferLenTag(reflectValue.Len()), nil
+	}
+	if reflectValue.CanConvert(reflect.TypeOf(dummyBuffer)) {
+		return bufferLenTag(reflectValue.Len()), nil
+	}
+	
+	// aggregates
+	reflectType := reflectValue.Type()
+	switch reflectType.Kind() {
+	case reflect.Slice: return OTA.WithCN(IntBytes(uint64(reflectValue.Len())) - 1), nil
+	case reflect.Array: return OTA.WithCN(reflectType.Len()), nil
+	case reflect.Map:
+		if reflectType.Key() == reflect.TypeOf(uint16(0)) {
+			return KTV.WithCN(IntBytes(uint64(reflectValue.Len())) - 1), nil
+		}
+		return 0, fmt.Errorf("cannot encode map key %v, key must be uint16", reflectType.Key())
+	}
+	return 0, fmt.Errorf("cannot get tag of type %v", reflectType)
+}
+
+func encodeAnySlice(encoder *Encoder, value any, tag Tag) (n int, err error) {
+	// OTA: <length: UN> <elementTag: tape.Tag> <values>*
+	reflectValue := reflect.ValueOf(value)
+	nn, err := encoder.WriteUintN(uint64(reflectValue.Len()), tag.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	reflectType := reflect.TypeOf(value)
+	oneTag, err := tagAny(reflect.Zero(reflectType.Elem()))
+	if err != nil { return n, err }
+	for index := 0; index < reflectValue.Len(); index += 1 {
+		itemTag, err := tagAny(reflectValue.Index(index))
+		if err != nil { return n, err }
+		if itemTag.CN() > oneTag.CN() { oneTag = itemTag }
+	}
+	if oneTag.Is(SBA) { oneTag += 1 << 5 }
+	nn, err = encoder.WriteUint8(uint8(oneTag))
+	n += nn; if err != nil { return n, err }
+	for index := 0; index < reflectValue.Len(); index += 1 {
+		item := reflectValue.Index(index).Interface()
+		nn, err = EncodeAny(encoder, item, oneTag)
+		n += nn; if err != nil { return n, err }
+	}
+	return n, err
+}
+
+func encodeAnyMap(encoder *Encoder, value any, tag Tag) (n int, err error) {
+	// KTV: <length: UN> (<key: U16> <tag: Tag> <value>)*
+	reflectValue := reflect.ValueOf(value)
+	nn, err := encoder.WriteUintN(uint64(reflectValue.Len()), tag.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	iter := reflectValue.MapRange()
+	for iter.Next() {
+		reflectValue := iter.Value().Elem()
+		key          := iter.Key().Interface().(uint16)
+		value        := reflectValue.Interface()
+		nn, err = encoder.WriteUint16(key)
+		n += nn; if err != nil { return n, err }
+		itemTag, err := tagAny(reflectValue)
+		if err != nil { return n, err }
+		nn, err = encoder.WriteUint8(uint8(itemTag))
+		n += nn; if err != nil { return n, err }
+		nn, err = EncodeAny(encoder, value, itemTag)
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+func canSet(destination reflect.Type, tag Tag) error {
+	// anything can be assigned to `any`
+	if isTypeAny(destination) {
+		return nil
+	}
+	switch tag.WithoutCN() {
+	case SI, LI, LSI:
+		switch destination.Kind() {
+		case
+			reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+			reflect.Bool:
+		default:
+			return errCantAssignf("cannot assign integer to %v", destination)
+		}
+	case FP:
+		switch destination.Kind() {
+		case reflect.Float32, reflect.Float64:
+		default:
+			return errCantAssignf("cannot assign float to %v", destination)
+		}
+	case SBA, LBA:
+		if destination.Kind() == reflect.String { return nil }
+		if destination.Kind() != reflect.Slice {
+			return errCantAssignf("cannot assign byte array to %v", destination)
+		}
+		if destination.Elem() != reflect.TypeOf(byte(0)) {
+			return errCantAssignf("cannot convert %v to *[]byte", destination)
+		}
+	case OTA:
+		if destination.Kind() != reflect.Slice {
+			return errCantAssignf("cannot assign array to %v", destination)
+		}
+	case KTV:
+		cantAssign :=
+			destination.Kind() != reflect.Map ||
+			destination.Key().Kind() != reflect.Uint16 ||
+			!isTypeAny(destination.Elem())
+		if cantAssign {
+			return errCantAssignf("cannot assign table to %v", destination)
+		}
+	default:
+		return fmt.Errorf("unknown TN %d", tag.TN())
+	}
+	return nil
+}
+
+// setInt expects a settable destination.
+func setInt(destination reflect.Value, value int64, bytes int) {
+	switch {
+	case destination.CanInt():
+		destination.Set(reflect.ValueOf(int64(value)).Convert(destination.Type()))
+	case destination.CanUint():
+		destination.Set(reflect.ValueOf(value).Convert(destination.Type()))
+	case isTypeAny(destination.Type()):
+		switch {
+		case bytes > 4: destination.Set(reflect.ValueOf(int64(value)))
+		case bytes > 2: destination.Set(reflect.ValueOf(int32(value)))
+		case bytes > 1: destination.Set(reflect.ValueOf(int16(value)))
+		default:        destination.Set(reflect.ValueOf(int8(value)))
+		}
+	default:
+		panic("setInt called on an unsupported type")
+	}
+}
+
+// setUint expects a settable destination.
+func setUint(destination reflect.Value, value uint64, bytes int) {
+	switch {
+	case destination.Kind() == reflect.Bool:
+		destination.Set(reflect.ValueOf(value > 0))
+	case destination.CanInt():
+		destination.Set(reflect.ValueOf(int64(value)).Convert(destination.Type()))
+	case destination.CanUint():
+		destination.Set(reflect.ValueOf(value).Convert(destination.Type()))
+	case isTypeAny(destination.Type()):
+		switch {
+		case bytes > 4: destination.Set(reflect.ValueOf(uint64(value)))
+		case bytes > 2: destination.Set(reflect.ValueOf(uint32(value)))
+		case bytes > 1: destination.Set(reflect.ValueOf(uint16(value)))
+		default:        destination.Set(reflect.ValueOf(uint8(value)))
+		}
+	default:
+		panic("setUint called on an unsupported type")
+	}
+}
+
+// setFloat expects a settable destination.
+func setFloat(destination reflect.Value, value float64) {
+	destination.Set(reflect.ValueOf(value).Convert(destination.Type()))
+}
+
+// setByteArrayexpects a settable destination.
+func setByteArray(destination reflect.Value, value []byte) {
+	destination.Set(reflect.ValueOf(value))
+}
+
+// setString exepctes a settable destination
+func setString(destination reflect.Value, value string) {
+	destination.Set(reflect.ValueOf(value))
+}
+
+// decodeAndSetInt expects a settable destination.
+func decodeAndSetInt(decoder *Decoder, destination reflect.Value, bytes int) (n int, err error) {
+	value, nn, err := decoder.ReadIntN(bytes)
+	n += nn; if err != nil { return n, err }
+	setInt(destination, value, bytes)
+	return n, nil
+}
+
+// decodeAndSetUint expects a settable destination.
+func decodeAndSetUint(decoder *Decoder, destination reflect.Value, bytes int) (n int, err error) {
+	value, nn, err := decoder.ReadUintN(bytes)
+	n += nn; if err != nil { return n, err }
+	setUint(destination, value, bytes)
+	return n, nil
+}
+
+// decodeAndSetInt expects a settable destination.
+func decodeAndSetFloat(decoder *Decoder, destination reflect.Value, bytes int) (n int, err error) {
+	switch bytes {
+	case 8:
+		value, nn, err := decoder.ReadFloat64()
+		n += nn; if err != nil { return n, err }
+		setFloat(destination, float64(value))
+		return n, nil
+	case 4:
+		value, nn, err := decoder.ReadFloat32()
+		n += nn; if err != nil { return n, err }
+		setFloat(destination, float64(value))
+		return n, nil
+	}
+	return n, errCantAssignf("unsupported bit width float%d", bytes * 8)
+}
+
+// skeletonValue returns an addressable value. It can be set directly. The head
+// of the decoder must be at the start of the payload when calling.
+func skeletonValue(decoder *Decoder, tag Tag) (reflect.Value, error) {
+	ptr, err := skeletonPointer(decoder, tag)
+	if err != nil { return reflect.Value { }, err }
+	return ptr.Elem(), nil
+}
+
+// skeletonPointer returns a pointer value. In order for it to be set, it must
+// be dereferenced using Elem(). The head of the decoder must be at the start of
+// the payload when calling.
+func skeletonPointer(decoder *Decoder, tag Tag) (reflect.Value, error) {
+	typ, err := typeOf(decoder, tag)
+	if err != nil { return reflect.Value { }, err }
+	value := reflect.New(typ)
+	return value, nil
+}
+
+// typeOf returns the type of the current tag being decoded. It does not use up
+// the decoder, it only peeks. The head of the decoder must be at the start of
+// the payload when calling.
+func typeOf(decoder *Decoder, tag Tag) (reflect.Type, error) {
+	switch tag.WithoutCN() {
+	case SI:
+		return reflect.TypeOf(uint8(0)), nil
+	case LI:
+		switch tag.CN() {
+		case 0: return reflect.TypeOf(uint8(0)), nil
+		case 1: return reflect.TypeOf(uint16(0)), nil
+		case 3: return reflect.TypeOf(uint32(0)), nil
+		case 7: return reflect.TypeOf(uint64(0)), nil
+		}
+		return nil, fmt.Errorf("unknown CN %d for LI", tag.CN())
+	case LSI:
+		switch tag.CN() {
+		case 0: return reflect.TypeOf(int8(0)), nil
+		case 1: return reflect.TypeOf(int16(0)), nil
+		case 3: return reflect.TypeOf(int32(0)), nil
+		case 7: return reflect.TypeOf(int64(0)), nil
+		}
+		return nil, fmt.Errorf("unknown CN %d for LSI", tag.CN())
+	case FP:
+		switch tag.CN() {
+		case 3: return reflect.TypeOf(float32(0)), nil
+		case 7: return reflect.TypeOf(float64(0)), nil
+		}
+		return nil, fmt.Errorf("unknown CN %d for FP", tag.CN())
+	case SBA: return reflect.TypeOf(""), nil
+	case LBA: return reflect.TypeOf(""), nil
+	case OTA:
+		elemTag, dimension, err := peekSlice(decoder, tag)
+		if err != nil { return nil, err }
+		if elemTag.Is(OTA) { panic("peekSlice cannot return OTA") }
+		typ, err := typeOf(decoder, elemTag)
+		if err != nil { return nil, err }
+		for _ = range dimension {
+			typ = reflect.SliceOf(typ)
+		}
+		return typ, nil
+	case KTV: return reflect.TypeOf(dummyMap), nil
+	}
+	return nil, fmt.Errorf("unknown TN %d", tag.TN())
+}
+
+// isTypeAny returns whether the given reflect.Type is an interface with no
+// methods.
+func isTypeAny(typ reflect.Type) bool {
+	return typ.Kind() == reflect.Interface && typ.NumMethod() == 0
+}
+
+// peekSlice returns the element tag and dimension count of the OTA currently
+// being decoded. It does not use up the decoder, it only peeks.
+func peekSlice(decoder *Decoder, tag Tag) (Tag, int, error) {
+	offset    := 0
+	dimension := 0
+	currentTag := tag
+	for {
+		elem, populated, n, err := peekSliceOnce(decoder, currentTag, offset)
+		if err != nil { return 0, 0, err }
+		currentTag = elem
+		offset     = n
+		dimension += 1
+		if elem.Is(OTA) {
+			if !populated {
+				// default to a large byte array, will be
+				// interpreted as a string.
+				return LBA, dimension + 1, nil
+			}
+		} else {
+			return elem, dimension, nil
+		}
+	}
+}
+
+// peekSliceOnce returns the element tag of the OTA located offset bytes ahead
+// of the current position. It does not use up the decoder, it only peeks. The n
+// return value denotes how far away from 0 it peeked. If the OTA has more than
+// zero items, populated will be set to true.
+func peekSliceOnce(decoder *Decoder, tag Tag, offset int) (elem Tag, populated bool, n int, err error) {
+	lengthStart  := offset
+	lengthEnd    := lengthStart + tag.CN() + 1
+	elemTagStart := lengthEnd
+	elemTagEnd   := elemTagStart + 1
+
+	headerBytes, err := decoder.Peek(elemTagEnd)
+	if err != nil { return 0, false, 0, err }
+
+	elem = Tag(headerBytes[len(headerBytes) - 1])
+	for index := lengthStart; index < lengthEnd; index += 1 {
+		if headerBytes[index] > 0 {
+			populated = true
+			break
+		}
+	}
+	n = elemTagEnd
+
+	return
+}

tape/dynamic_test.go

@@ -0,0 +1,397 @@
+package tape
+
+import "bytes"
+import "testing"
+import "reflect"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+
+var samplePayloads = [][]byte {
+	/* int8     */ []byte { byte(LSI.WithCN(0)), 0x45 },
+	/* int16    */ []byte { byte(LSI.WithCN(1)), 0x45, 0x67 },
+	/* int32    */ []byte { byte(LSI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
+	/* int64    */ []byte { byte(LSI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
+	/* uint5    */ []byte { byte(SI.WithCN(12)) },
+	/* uint8    */ []byte { byte(LI.WithCN(0)), 0x45 },
+	/* uint16   */ []byte { byte(LI.WithCN(1)), 0x45, 0x67 },
+	/* uint32   */ []byte { byte(LI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
+	/* uint64   */ []byte { byte(LI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
+	/* bool     */ []byte { byte(SI.WithCN(0)) },
+	/* bool     */ []byte { byte(SI.WithCN(1)) },
+	/* string   */ []byte { byte(SBA.WithCN(7)), 'p', 'u', 'p', 'e', 'v', 'e', 'r' },
+	/* []byte   */ []byte { byte(SBA.WithCN(5)), 'b', 'l', 'a', 'r', 'g' },
+	/* []string */ []byte {
+		byte(OTA.WithCN(0)), 2, byte(LBA.WithCN(0)),
+		0x08, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23,
+		0x05, 0x11, 0x11, 0x11, 0x11, 0x11,
+	},
+	/* map[uint16] any */ []byte {
+		byte(KTV.WithCN(0)), 2,
+		0x02, 0x23, byte(LSI.WithCN(1)), 0x45, 0x67,
+		0x02, 0x24, byte(LI.WithCN(3)),  0x45, 0x67, 0x89, 0xAB,
+	},
+	/* map[uint16] any */ []byte {
+		byte(KTV.WithCN(0)), 3,
+		0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00,
+		0x00, 0x02, 0x82, 'h', 'i',
+		0x00, 0x03, 0x21, 0x39, 0x92,
+	},
+}
+
+var sampleValues = []any {
+	/* int8     */ int8(0x45),
+	/* int16    */ int16(0x4567),
+	/* int32    */ int32(0x456789AB),
+	/* int64    */ int64(0x456789ABCDEF0123),
+	/* uint5    */ uint8(12),
+	/* uint8    */ uint8(0x45),
+	/* uint16   */ uint16(0x4567),
+	/* uint32   */ uint32(0x456789AB),
+	/* uint64   */ uint64(0x456789ABCDEF0123),
+	/* bool     */ false,
+	/* bool     */ true,
+	/* string   */ "pupever",
+	/* []byte   */ "blarg",
+	/* []string */ []string {
+		"\x45\x67\x89\xAB\xCD\xEF\x01\x23",
+		"\x11\x11\x11\x11\x11",
+	},
+	/* map[uint16] any */ map[uint16] any {
+		0x0223: int16(0x4567),
+		0x0224: uint32(0x456789AB),
+	},
+	/* map[uint16] any */ map[uint16] any {
+		0x0001: float32(489.5),
+		0x0002: "hi",
+		0x0003: uint16(0x3992),
+	},
+}
+
+type userDefinedInteger int16
+
+func TestEncodeAnyInt(test *testing.T) {
+	err := testEncodeAny(test, uint8(0xCA), LI.WithCN(0), tu.S(0xCA))
+	if err != nil { test.Fatal(err) }
+	err = testEncodeAny(test, 400, LSI.WithCN(3), tu.S(
+		0, 0, 0x1, 0x90,
+	))
+	if err != nil { test.Fatal(err) }
+}
+
+func TestEncodeAnyTable(test *testing.T) {
+	err := testEncodeAny(test, map[uint16] any {
+		0xF3B9: 1,
+		0x0102: 2,
+		0x0000: "hi!",
+		0xFFFF: []uint16 { 0xBEE5, 0x7777 },
+		0x1234: [][]uint16 { []uint16 { 0x5 }, []uint16 { 0x17, 0xAAAA} },
+		0x2345: [][]int16 { []int16 { 0x5 }, []int16 { 0x17, -0xAAA } },
+		0x3456: userDefinedInteger(0x3921),
+		0x1F1F: float32(67.26),
+		0x0F0F: float64(5.3),
+		0xAAAA: false,
+		0xBBBB: true,
+	}, KTV.WithCN(0), tu.S(11).AddVar(
+		[]byte {
+			0xF3, 0xB9,
+			byte(LSI.WithCN(3)),
+			0, 0, 0, 1,
+		},
+		[]byte {
+			0x01, 0x02,
+			byte(LSI.WithCN(3)),
+			0, 0, 0, 2,
+		},
+		[]byte {
+			0, 0,
+			byte(SBA.WithCN(3)),
+			'h', 'i', '!',
+		},
+		[]byte {
+			0xFF, 0xFF,
+			byte(OTA.WithCN(0)), 2, byte(LI.WithCN(1)),
+			0xBE, 0xE5, 0x77, 0x77,
+		},
+		[]byte {
+			0x12, 0x34,
+			byte(OTA.WithCN(0)), 2, byte(OTA.WithCN(0)),
+			1, byte(LI.WithCN(1)),
+			0, 0x5,
+			2, byte(LI.WithCN(1)),
+			0,    0x17,
+			0xAA, 0xAA,
+		},
+		[]byte {
+			0x23, 0x45,
+			byte(OTA.WithCN(0)), 2, byte(OTA.WithCN(0)),
+			1, byte(LSI.WithCN(1)),
+			0, 0x5,
+			2, byte(LSI.WithCN(1)),
+			0,    0x17,
+			0xF5, 0x56,
+		},
+		[]byte {
+			0x34, 0x56,
+			byte(LSI.WithCN(1)),
+			0x39, 0x21,
+		},
+		[]byte {
+			0x1F, 0x1F,
+			byte(FP.WithCN(3)),
+			0x42, 0x86, 0x85, 0x1F,
+		},
+		[]byte {
+			0x0F, 0x0F,
+			byte(FP.WithCN(7)),
+			0x40, 0x15, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33,
+		},
+		[]byte {
+			0xAA, 0xAA,
+			byte(SI.WithCN(0)),
+		},
+		[]byte {
+			0xBB, 0xBB,
+			byte(SI.WithCN(1)),
+		},
+	))
+	if err != nil { test.Fatal(err) }
+}
+
+func TestDecodeWrongType(test *testing.T) {
+	for index, data := range samplePayloads {
+		test.Logf("data %2d %v [%s]", index, Tag(data[0]), tu.HexBytes(data[1:]))
+		// integers should only assign to other integers
+		if index > 10 {
+			cas := func(destination any) {
+				n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(data[1:])), destination, Tag(data[0]))
+				if err != nil { test.Fatalf("error: %v | n: %d", err, n) }
+				reflectValue := reflect.ValueOf(destination).Elem()
+				if reflectValue.CanInt() {
+					if reflectValue.Int() != 0 {
+						test.Fatalf("destination not zero: %v", reflectValue.Elem().Interface())
+					}
+				} else if reflectValue.Kind() != reflect.Bool {
+					if reflectValue.Uint() != 0 {
+						test.Fatalf("destination not zero: %v", reflectValue.Elem().Interface())
+					}
+				}
+				if n != len(data) - 1 {
+					test.Fatalf("n not equal: %d != %d", n, len(data) - 1)
+				}
+			}
+			test.Log("- int8")
+			{ var dest int8;   cas(&dest) }
+			test.Log("- int16")
+			{ var dest int16;  cas(&dest) }
+			test.Log("- int32")
+			{ var dest int32;  cas(&dest) }
+			test.Log("- int64")
+			{ var dest int64;  cas(&dest) }
+			test.Log("- uint8")
+			{ var dest uint8;  cas(&dest) }
+			test.Log("- uint16")
+			{ var dest uint16; cas(&dest) }
+			test.Log("- uint32")
+			{ var dest uint32; cas(&dest) }
+			test.Log("- uint64")
+			{ var dest uint64; cas(&dest) }
+			test.Log("- bool")
+			{ var dest bool; cas(&dest) }
+		}
+		arrayCase := func(destination any) {
+			n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(data[1:])), destination, Tag(data[0]))
+			if err != nil { test.Fatalf("error: %v | n: %d", err, n) }
+			reflectDestination := reflect.ValueOf(destination)
+			reflectValue := reflectDestination.Elem()
+			if reflectValue.Len() != 0 {
+				test.Fatalf("len(destination) not zero: %v", reflectValue.Interface())
+			}
+			if n != len(data) - 1 {
+				test.Fatalf("n not equal: %d != %d", n, len(data) - 1)
+			}
+		}
+		// SBA/LBA types should only assign to other SBA/LBA types
+		if index != 11 && index != 12 {
+			test.Log("- string")
+			{ var dest string; arrayCase(&dest) }
+			test.Log("- []byte")
+			{ var dest []byte; arrayCase(&dest) }
+		}
+		// arrays should only assign to other arrays
+		if index != 13 {
+			test.Log("- []string")
+			{ var dest []string; arrayCase(&dest) }
+		}
+		// tables should only assign to other tables
+		if index != 14 && index != 15 {
+			test.Log("- map[uint16] any")
+			{ var dest = map[uint16] any { }; arrayCase(&dest) }
+		}
+	}
+}
+
+func TestEncodeDecodeAnyTable(test *testing.T) {
+	err := testEncodeDecodeAny(test, map[uint16] any {
+		0xF3B9: uint32(1),
+		0x0102: uint32(2),
+		0x0103: int64(23432),
+		0x0104: int64(-88777),
+		0x0000: "hi!",
+		0xFFFF: []uint16 { 0xBEE5, 0x7777 },
+		0x1234: [][]uint16 { []uint16 { 0x5 }, []uint16 { 0x17, 0xAAAA} },
+		0x1F1F: float32(67.26),
+		0x0F0F: float64(5.3),
+	}, nil)
+	if err != nil { test.Fatal(err) }
+}
+
+func TestEncodeDecodeAnyDestination(test *testing.T) {
+	var destination any
+	for index, data := range samplePayloads {
+		if _, isBool := sampleValues[index].(bool); isBool {
+			// test is invalid for bools because they are never
+			// created as a skeleton value
+			continue
+		}
+	
+		tag     := Tag(data[0])
+		payload := data[1:]
+		test.Logf("data %2d %v [%s]", index, tag, tu.HexBytes(payload))
+		n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(payload)), &destination, tag)
+		if err != nil { test.Fatalf("error: %v | n: %d", err, n) }
+		got     := destination
+		correct := sampleValues[index]
+		test.Log("got:    ", tu.Describe(got))
+		test.Log("correct:", tu.Describe(correct))
+		if !reflect.DeepEqual(got, correct) {
+			test.Fatalf("values not equal")
+		}
+		if n != len(payload) {
+			test.Fatalf("n not equal: %d != %d", n, len(payload))
+		}
+	}
+}
+
+func TestPeekSlice(test *testing.T) {
+	buffer := bytes.NewBuffer([]byte {
+		2, byte(OTA.WithCN(3)),
+		0, 0, 0, 1, byte(LI.WithCN(1)),
+		0, 0x5,
+		2, byte(LI.WithCN(1)),
+		0,    0x17,
+		0xAA, 0xAA,
+	})
+	decoder := NewDecoder(buffer)
+
+	elem, dimension, err := peekSlice(decoder, OTA.WithCN(0))
+	if err != nil { test.Fatal(err) }
+	if elem != LI.WithCN(1) {
+		test.Fatalf("wrong element tag: %v %02X", elem, byte(elem))
+	}
+	if got, correct := dimension, 2; got != correct {
+		test.Fatalf("wrong dimension: %d != %d", got, correct)
+	}
+}
+
+func TestPeekSliceOnce(test *testing.T) {
+	buffer := bytes.NewBuffer([]byte {
+		2, byte(OTA.WithCN(3)),
+		0, 0, 0, 1, byte(LI.WithCN(1)),
+		0, 0x5,
+		2, byte(LI.WithCN(1)),
+		0,    0x17,
+		0xAA, 0xAA,
+	})
+	decoder := NewDecoder(buffer)
+
+	test.Log("--- stage 1")
+	elem, populated, n, err := peekSliceOnce(decoder, OTA.WithCN(0), 0)
+	if err != nil { test.Fatal(err) }
+	if elem != OTA.WithCN(3) {
+		test.Fatal("wrong element tag:", elem)
+	}
+	if !populated {
+		test.Fatal("wrong populated:", populated)
+	}
+	if got, correct := n, 2; got != correct {
+		test.Fatalf("wrong n: %d != %d", got, correct)
+	}
+	
+	test.Log("--- stage 2")
+	elem, populated, n, err = peekSliceOnce(decoder, elem, n)
+	if err != nil { test.Fatal(err) }
+	if elem != LI.WithCN(1) {
+		test.Fatal("wrong element tag:", elem)
+	}
+	if !populated {
+		test.Fatal("wrong populated:", populated)
+	}
+	if got, correct := n, 7; got != correct {
+		test.Fatalf("wrong n: %d != %d", got, correct)
+	}
+}
+
+func TestTagAny(test *testing.T) {
+	cases := [][2]any {
+		[2]any { LSI.WithCN(3),  int(9)     },
+		[2]any { LSI.WithCN(0),  int8(9)    },
+		[2]any { LSI.WithCN(1),  int16(9)   },
+		[2]any { LSI.WithCN(3),  int32(9)   },
+		[2]any { LSI.WithCN(7),  int64(9)   },
+		[2]any { LI.WithCN(3),   uint(9)    },
+		[2]any { LI.WithCN(0),   uint8(9)   },
+		[2]any { LI.WithCN(1),   uint16(9)  },
+		[2]any { LI.WithCN(3),   uint32(9)  },
+		[2]any { LI.WithCN(7),   uint64(9)  },
+		[2]any { FP.WithCN(3),   float32(9) },
+		[2]any { FP.WithCN(7),   float64(9) },
+		[2]any { SBA.WithCN(12), "small string" },
+		[2]any { SBA.WithCN(12), []byte("small string") },
+		[2]any { LBA.WithCN(0),  "this is a very long string that is long" },
+		[2]any { LBA.WithCN(0),  []byte("this is a very long string that is long") },
+		[2]any { LBA.WithCN(1),  lipsum },
+		[2]any { OTA.WithCN(0),  []int { 1, 2, 3, 4, 5 } },
+		[2]any { OTA.WithCN(0),  []string { "1, 2, 3, 4, 5" } },
+		[2]any { KTV.WithCN(0),  map[uint16] any {
+			0:  1,
+			1:  "wow",
+			2:  10.238,
+			45: -9,
+			9:  map[uint16] any { },
+		}},
+	}
+	for _, cas := range cases {
+		test.Log(cas)
+		got, err := TagAny(cas[1])
+		if err != nil { test.Fatal(err) }
+		if correct := cas[0].(Tag); correct != got {
+			test.Fatalf("wrong tag: %v != %v", got, correct)
+		}
+	}
+}
+
+func TestDecodeAny(test *testing.T) {
+	for index, payload := range samplePayloads {
+		if _, isBool := sampleValues[index].(bool); isBool {
+			// test is invalid for bools because they are never
+			// created as a skeleton value
+			continue
+		}
+		
+		correctValue := sampleValues[index]
+		data := payload[1:]
+		decoder := NewDecoder(bytes.NewBuffer(data))
+		tag     := Tag(payload[0])
+		decoded, n, err := DecodeAny(decoder, tag)
+		test.Log("n:      ", n)
+		test.Log("tag:    ", tag)
+		test.Log("got:    ", tu.Describe(decoded))
+		test.Log("correct:", tu.Describe(correctValue))
+		if err != nil { test.Fatal(err) }
+		if !reflect.DeepEqual(decoded, correctValue) {
+			test.Fatal("values not equal")
+		}
+		if n != len(data) {
+			test.Fatalf("n not equal: %d != %d", n, len(data))
+		}
+	}
+}

tape/encode.go

@@ -0,0 +1,189 @@
+package tape
+
+import "io"
+import "math"
+import "bufio"
+
+// Encodable is any type that can write itself to an encoder.
+type Encodable interface {
+	// Encode sends data to encoder. It returns the amount of bytes written,
+	// and an error if the write stopped early.
+	Encode(encoder *Encoder) (n int, err error)
+}
+	
+// Encoder encodes data to an io.Writer.
+type Encoder struct {
+	bufio.Writer
+}
+
+// NewEncoder creates a new encoder that writes to writer.
+func NewEncoder(writer io.Writer) *Encoder {
+	encoder := &Encoder { }
+	encoder.Reset(writer)
+	return encoder
+}
+
+// WriteInt8 encodes an 8-bit signed integer to the output writer.
+func (this *Encoder) WriteInt8(value int8) (n int, err error) {
+	return this.WriteUint8(uint8(value))
+}
+
+// WriteUint8 encodes an 8-bit unsigned integer to the output writer.
+func (this *Encoder) WriteUint8(value uint8) (n int, err error) {
+	return this.Write([]byte { byte(value) })
+}
+
+// WriteInt16 encodes an 16-bit signed integer to the output writer.
+func (this *Encoder) WriteInt16(value int16) (n int, err error) {
+	return this.WriteUint16(uint16(value))
+}
+
+// WriteUint16 encodes an 16-bit unsigned integer to the output writer.
+func (this *Encoder) WriteUint16(value uint16) (n int, err error) {
+	return this.Write([]byte {
+		byte(value >> 8),
+		byte(value),
+	})
+}
+
+// WriteInt32 encodes an 32-bit signed integer to the output writer.
+func (this *Encoder) WriteInt32(value int32) (n int, err error) {
+	return this.WriteUint32(uint32(value))
+}
+
+// WriteUint32 encodes an 32-bit unsigned integer to the output writer.
+func (this *Encoder) WriteUint32(value uint32) (n int, err error) {
+	return this.Write([]byte {
+		byte(value >> 24),
+		byte(value >> 16),
+		byte(value >> 8),
+		byte(value),
+	})
+}
+
+// WriteInt64 encodes an 64-bit signed integer to the output writer.
+func (this *Encoder) WriteInt64(value int64) (n int, err error) {
+	return this.WriteUint64(uint64(value))
+}
+
+// WriteUint64 encodes an 64-bit unsigned integer to the output writer.
+func (this *Encoder) WriteUint64(value uint64) (n int, err error) {
+	return this.Write([]byte {
+		byte(value >> 56),
+		byte(value >> 48),
+		byte(value >> 40),
+		byte(value >> 32),
+		byte(value >> 24),
+		byte(value >> 16),
+		byte(value >> 8),
+		byte(value),
+	})
+}
+
+// WriteIntN encodes an N-byte signed integer to the output writer.
+func (this *Encoder) WriteIntN(value int64, bytes int) (n int, err error) {
+	return this.WriteUintN(uint64(value), bytes)
+}
+
+// for Write/ReadUintN, increase buffers if go somehow gets support for over 64
+// bit integers. we could also make an expanding int type in goutil to use here,
+// or maybe there is one in the stdlib. keep the int64 versions as well though
+// because its ergonomic.
+	
+// WriteUintN encodes an N-byte unsigned integer to the output writer.
+func (this *Encoder) WriteUintN(value uint64, bytes int) (n int, err error) {
+	// TODO: don't make multiple write calls (without allocating)
+	buffer := [1]byte { }
+	for bytesLeft := bytes; bytesLeft > 0; bytesLeft -- {
+		buffer[0] = byte(value) >> ((bytesLeft - 1) * 8)
+		nn, err := this.Write(buffer[:])
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// WriteFloat16 encodes a 16-bit floating point value to the output writer.
+func (this *Encoder) WriteFloat16(value float32) (n int, err error) {
+	return this.WriteUint16(f32bitsToF16bits(math.Float32bits(value)))
+}
+
+// WriteFloat32 encodes a 32-bit floating point value to the output writer.
+func (this *Encoder) WriteFloat32(value float32) (n int, err error) {
+	return this.WriteUint32(math.Float32bits(value))
+}
+
+// WriteFloat64 encodes a 64-bit floating point value to the output writer.
+func (this *Encoder) WriteFloat64(value float64) (n int, err error) {
+	return this.WriteUint64(math.Float64bits(value))
+}
+
+// WriteTag encodes a [Tag] to the output writer.
+func (this *Encoder) WriteTag(value Tag) (n int, err error) {
+	return this.WriteUint8(uint8(value))
+}
+
+// f32bitsToF16bits returns uint16 (Float16 bits) converted from the specified float32.
+// Conversion rounds to nearest integer with ties to even.
+// Taken from https://github.com/x448/float16/blob/v0.8.4/float16
+//
+// MIT License
+// 
+// Copyright (c) 2019 Montgomery Edwards⁴⁴⁸ and Faye Amacker
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+func f32bitsToF16bits(u32 uint32) uint16 {
+	// Translated from Rust to Go by Montgomery Edwards⁴⁴⁸ (github.com/x448).
+	// All 4294967296 conversions with this were confirmed to be correct by x448.
+	// Original Rust implementation is by Kathryn Long (github.com/starkat99) with MIT license.
+
+	sign := u32 & 0x80000000
+	exp := u32 & 0x7f800000
+	coef := u32 & 0x007fffff
+
+	if exp == 0x7f800000 {
+		// NaN or Infinity
+		nanBit := uint32(0)
+		if coef != 0 {
+			nanBit = uint32(0x0200)
+		}
+		return uint16((sign >> 16) | uint32(0x7c00) | nanBit | (coef >> 13))
+	}
+
+	halfSign := sign >> 16
+
+	unbiasedExp := int32(exp>>23) - 127
+	halfExp := unbiasedExp + 15
+
+	if halfExp >= 0x1f {
+		return uint16(halfSign | uint32(0x7c00))
+	}
+
+	if halfExp <= 0 {
+		if 14-halfExp > 24 {
+			return uint16(halfSign)
+		}
+		coef := coef | uint32(0x00800000)
+		halfCoef := coef >> uint32(14-halfExp)
+		roundBit := uint32(1) << uint32(13-halfExp)
+		if (coef&roundBit) != 0 && (coef&(3*roundBit-1)) != 0 {
+			halfCoef++
+		}
+		return uint16(halfSign | halfCoef)
+	}
+
+	uHalfExp := uint32(halfExp) << 10
+	halfCoef := coef >> 13
+	roundBit := uint32(0x00001000)
+	if (coef&roundBit) != 0 && (coef&(3*roundBit-1)) != 0 {
+		return uint16((halfSign | uHalfExp | halfCoef) + 1)
+	}
+	return uint16(halfSign | uHalfExp | halfCoef)
+}

tape/error.go

@@ -0,0 +1,12 @@
+package tape
+
+// Error enumerates common errors in this package.
+type Error string; const (
+	ErrTooLong  Error = "data structure too long"
+	ErrTooLarge Error = "number too large"
+)
+
+// Error implements the error interface.
+func (err Error) Error() string {
+	return string(err)
+}

tape/limits.go

@@ -0,0 +1,26 @@
+package tape
+
+// MaxStructureLength determines how long a TAPE data structure can be. This
+// applies to:
+//
+//  - OTA
+//  - SBA/LBA
+//  - KTV
+//
+// By default it is set at 2^20 (about a million).
+// You shouldn't need to change this. If you do, it should only be set once at
+// the start of the program.
+var MaxStructureLength = 1024 * 1024
+
+// MaxInt is the maximum value an int can hold. This varies depending on the
+// system.
+const MaxInt int = int(^uint(0) >> 1)
+
+// Uint64ToIntSafe casts the input to an int if it can be done without overflow,
+// or returns an error otherwise.
+func Uint64ToIntSafe(input uint64) (int, error) {
+	if input > uint64(MaxInt) {
+		return 0, ErrTooLarge
+	}
+	return int(input), nil
+}

tape/measure.go

@@ -0,0 +1,12 @@
+package tape
+
+// IntBytes returns the number of bytes required to hold a given unsigned
+// integer.
+func IntBytes(value uint64) int {
+	bytes := 0
+	for value > 0 || bytes == 0 {
+		value >>= 8;
+		bytes ++
+	}
+	return bytes
+}

tape/measure_test.go

@@ -0,0 +1,21 @@
+package tape
+
+import "testing"
+
+func TestIntBytes(test *testing.T) {
+	if correct, got := 1, IntBytes(0); correct != got {
+		test.Fatal("wrong:", got)
+	}
+	if correct, got := 1, IntBytes(1); correct != got {
+		test.Fatal("wrong:", got)
+	}
+	if correct, got := 1, IntBytes(16); correct != got {
+		test.Fatal("wrong:", got)
+	}
+	if correct, got := 1, IntBytes(255); correct != got {
+		test.Fatal("wrong:", got)
+	}
+	if correct, got := 2, IntBytes(256); correct != got {
+		test.Fatal("wrong:", got)
+	}
+}

tape/misc_test.go

@@ -0,0 +1,75 @@
+package tape
+
+import "fmt"
+import "bytes"
+import "testing"
+import "reflect"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+
+func encAny(value any) ([]byte, Tag, int, error) {
+	tag, err := TagAny(value)
+	if err != nil { return nil, 0, 0, err }
+	buffer := bytes.Buffer { }
+	encoder := NewEncoder(&buffer)
+	n, err := EncodeAny(encoder, value, tag)
+	if err != nil { return nil, 0, n, err }
+	encoder.Flush()
+	return buffer.Bytes(), tag, n, nil
+}
+
+func decAny(data []byte) (Tag, any, int, error) {
+	destination := map[uint16] any { }
+	tag, err := TagAny(destination)
+	if err != nil { return 0, nil, 0, err }
+	n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(data)), &destination, tag)
+	if err != nil { return 0, nil, n, err }
+	return tag, destination, n, nil
+}
+
+func testEncodeAny(test *testing.T, value any, correctTag Tag, correctBytes tu.Snake) error {
+	bytes, tag, n, err := encAny(value)
+	if err != nil { return err }
+	test.Log("n:      ", n)
+	test.Log("tag:    ", tag)
+	test.Log("got:    ", tu.HexBytes(bytes))
+	test.Log("correct:", correctBytes)
+	if tag != correctTag {
+		return fmt.Errorf("tag not equal: %v != %v", tag, correctTag)
+	}
+	if ok, n := correctBytes.Check(bytes); !ok {
+		return fmt.Errorf("bytes not equal at index %d", n)
+	}
+	if n != len(bytes) {
+		return fmt.Errorf("n not equal: %d != %d", n, len(bytes))
+	}
+	return nil
+}
+
+func testEncodeDecodeAny(test *testing.T, value, correctValue any) error {
+	if correctValue == nil { 
+		correctValue = value
+	}
+
+	test.Log("encoding...")
+	bytes, tag, n, err := encAny(value)
+	if err != nil { return err }
+	test.Log("n:  ", n)
+	test.Log("tag:", tag)
+	test.Log("got:", tu.HexBytes(bytes))
+	test.Log("decoding...", tag)
+	if n != len(bytes) {
+		return fmt.Errorf("n not equal: %d != %d", n, len(bytes))
+	}
+	
+	_, decoded, n, err := decAny(bytes)
+	if err != nil { return err }
+	test.Log("got:    ", tu.Describe(decoded))
+	test.Log("correct:", tu.Describe(correctValue))
+	if !reflect.DeepEqual(decoded, correctValue) {
+		return fmt.Errorf("values not equal")
+	}
+	if n != len(bytes) {
+		return fmt.Errorf("n not equal: %d != %d", n, len(bytes))
+	}
+	return nil
+}

tape/pairs.go

@@ -1,83 +0,0 @@
-package tape
-
-import "iter"
-
-// DecodePairs decodes message tag/value pairs from a byte slice. It returns an
-// iterator over all pairs, where the first value is the tag and the second is
-// the value. If data yielded by the iterator is retained, it must be copied
-// first.
-func DecodePairs(data []byte) (iter.Seq2[uint16, []byte], error) {
-	// determine section bounds
-	if len(data) < 2 { return nil, ErrDataTooLarge }
-	length16, _ := DecodeI16[uint16](data[0:2])
-	data = data[2:]
-	length := int(length16)
-	headerSize := length * 4
-	if len(data) < headerSize { return nil, ErrDataTooLarge }
-	valuesData := data[headerSize:]
-
-	// ensure the value buffer is big enough
-	var valuesSize int
-	for index := range length {
-		offset := index * 4
-		end, _ := DecodeI16[uint16](data[offset + 2:offset + 4])
-		valuesSize = int(end)
-	}
-	if valuesSize > len(valuesData) {
-		return nil, ErrDataTooLarge
-	}
-
-	// return iterator
-	return func(yield func(uint16, []byte) bool) {
-		start := uint16(0)
-		for index := range length {
-			offset := index * 4
-			key , _ := DecodeI16[uint16](data[offset + 0:offset + 2])
-			end,  _ := DecodeI16[uint16](data[offset + 2:offset + 4])
-			// if nextValuesOffset < len(valuesData) {
-				if !yield(key, valuesData[start:end]) {
-					return
-				}
-			// } else {
-				// if !yield(key, nil) {
-					// return
-				// }
-			// }
-			start = end
-		}
-	}, nil
-}
-
-// EncodePairs encodes message tag/value pairs into a byte slice.
-func EncodePairs(pairs map[uint16] []byte) ([]byte, error) {
-	// determine section bounds
-	headerSize := 2 + len(pairs) * 4
-	valuesSize := 0
-	for _, value := range pairs {
-		valuesSize += len(value)
-	}
-
-	// generate data
-	buffer := make([]byte, headerSize + valuesSize)
-	length16, ok := U16CastSafe(len(pairs))
-	if !ok { return nil, ErrDataTooLarge }
-	EncodeI16[uint16](buffer[0:2], length16)
-	index  := 0
-	end    := headerSize
-	for key, value := range pairs {
-		start := end
-		end += len(value)
-		tagOffset := 2 + index * 4
-		end16, ok := U16CastSafe(end - headerSize)
-		if !ok { return nil, ErrDataTooLarge }
-		
-		// write tag and length
-		EncodeI16[uint16](buffer[tagOffset + 0:tagOffset + 2], key)
-		EncodeI16[uint16](buffer[tagOffset + 2:tagOffset + 4], end16)
-
-		// write value
-		copy(buffer[start:end], value)
-		index ++
-	}
-	return buffer, nil
-}

tape/pairs_test.go

@@ -1,62 +0,0 @@
-package tape
-
-import "slices"
-import "testing"
-
-func TestDecodePairs(test *testing.T) {
-	pairs := map[uint16] []byte {
-		3894: []byte("foo"),
-		7:    []byte("br"),
-	}
-	got, err := DecodePairs([]byte {
-		  0,   2,
-		  0,   7,   0,  2,
-		 15,  54,   0,  5,
-		 98, 114,
-		102, 111, 111})
-	if err != nil { test.Fatal(err) }
-	length := 0
-	for key, value := range got {
-		test.Log(key, value)
-		if !slices.Equal(pairs[key], value) { test.Fatal("not equal") }
-		length ++
-	}
-	test.Log("length")
-	if length != len(pairs) { test.Fatal("wrong length") }
-}
-
-func TestEncodePairs(test *testing.T) {
-	pairs := map[uint16] []byte {
-		3894: []byte("foo"),
-		7:    []byte("br"),
-	}
-	got, err := EncodePairs(pairs)
-	if err != nil { test.Fatal(err) }
-	test.Log(got)
-	valid := slices.Equal(got, []byte {
-		  0,   2,
-		 15,  54,   0,  3,
-		  0,   7,   0,  5,
-		102, 111, 111,
-		 98, 114}) ||
-	slices.Equal(got, []byte {
-		  0,   2,
-		  0,   7,   0,  2,
-		 15,  54,   0,  5,
-		 98, 114,
-		102, 111, 111})
-	if !valid { test.Fatal("not equal") }
-}
-
-func FuzzDecodePairs(fuzz *testing.F) {
-	fuzz.Add([]byte {
-		  0,   2,
-		  0,   7,   0,  2,
-		 15,  54,   0,  5,
-		 98, 114,
-		102, 111, 111})
-	fuzz.Fuzz(func(t *testing.T, buffer []byte) {
-		// ensure it does not panic :P
-		DecodePairs(buffer)
-	})
-}

tape/skim.go

@@ -0,0 +1,54 @@
+package tape
+
+import "fmt"
+
+// Skim uses up data from a decoder to "skim" over one value (and all else
+// contained within it) without actually putting the data anywhere.
+func Skim(decoder *Decoder, tag Tag) (n int, err error) {
+	switch tag.WithoutCN() {
+	case SI:
+		// SI: (none)
+		return n, nil
+	case LI, LSI, FP:
+		// LI: <value: IntN>
+		// LSI: <value: IntN>
+		// FP: <value: FloatN>
+		nn, err := decoder.Discard(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+	case SBA:
+		// SBA: <data: U8>*
+		nn, err := decoder.Discard(tag.CN())
+		n += nn; if err != nil { return n, err }
+	case LBA:
+		// LBA: <length: UN> <data: U8>*
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		nn, err = decoder.Discard(int(length))
+		n += nn; if err != nil { return n, err }
+	case OTA:
+		// OTA: <length: UN> <elementTag: tape.Tag> <values>*
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		oneTag, nn, err := decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		for _ = range length {
+			nn, err := Skim(decoder, oneTag)
+			n += nn; if err != nil { return n, err }
+		}
+	case KTV:
+		// KTV: <length: UN> (<key: U16> <tag: Tag> <value>)*
+		length, nn, err := decoder.ReadUintN(tag.CN() + 1)
+		n += nn; if err != nil { return n, err }
+		for _ = range length {
+			nn, err := decoder.Discard(2)
+			n += nn; if err != nil { return n, err }
+			itemTag, nn, err := decoder.ReadTag()
+			n += nn; if err != nil { return n, err }
+			nn, err = Skim(decoder, itemTag)
+			n += nn; if err != nil { return n, err }
+		}
+	default:
+		return n, fmt.Errorf("unknown TN %d", tag.TN())
+	}
+	return n, nil
+}

tape/skim_test.go

@@ -0,0 +1,137 @@
+package tape
+
+import "bytes"
+import "testing"
+
+func TestSkimInteger(test *testing.T) {
+	data := []byte {
+		0x12, 0x45, 0x23, 0xF9,
+	}
+	mainDataLen := len(data)
+	// extra junk
+	data = append(data, 0x00, 0x01, 0x02, 0x03,)
+
+	n, err := Skim(NewDecoder(bytes.NewBuffer(data)), LI.WithCN(3))
+	if err != nil {
+		test.Fatal(err)
+	}
+	if got, correct := n, mainDataLen; got != correct {
+		test.Fatalf("n not equal: %d != %d", got, correct)
+	}
+}
+
+func TestSkimArray(test *testing.T) {
+	data := []byte {
+		2, byte(LI.WithCN(1)),
+		0xBE, 0xE5, 0x77, 0x77,
+	}
+	mainDataLen := len(data)
+	// extra junk
+	data = append(data, 0x00, 0x01, 0x02, 0x03,)
+
+	n, err := Skim(NewDecoder(bytes.NewBuffer(data)), OTA.WithCN(0))
+	if err != nil {
+		test.Fatal(err)
+	}
+	if got, correct := n, mainDataLen; got != correct {
+		test.Fatalf("n not equal: %d != %d", got, correct)
+	}
+}
+
+func TestSkimNestedArray(test *testing.T) {
+	data := []byte {
+		2, byte(OTA.WithCN(0)),
+		1, byte(LSI.WithCN(1)),
+		0, 0x5,
+		2, byte(LSI.WithCN(1)),
+		0,    0x17,
+		0xF5, 0x56,
+	}
+	mainDataLen := len(data)
+	// extra junk
+	data = append(data, 0x00, 0x01, 0x02, 0x03,)
+
+	n, err := Skim(NewDecoder(bytes.NewBuffer(data)), OTA.WithCN(0))
+	if err != nil {
+		test.Fatal(err)
+	}
+	if got, correct := n, mainDataLen; got != correct {
+		test.Fatalf("n not equal: %d != %d", got, correct)
+	}
+}
+
+func TestSkimTable(test *testing.T) {
+	data := []byte {
+		2,
+		0xF3, 0xB9,
+		byte(LSI.WithCN(3)),
+		0, 0, 0, 1,
+	
+		0x01, 0x02,
+		byte(LSI.WithCN(3)),
+		0, 0, 0, 2,
+	}
+	mainDataLen := len(data)
+	// extra junk
+	data = append(data, 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03)
+
+	n, err := Skim(NewDecoder(bytes.NewBuffer(data)), KTV.WithCN(0))
+	if got, correct := n, mainDataLen; got != correct {
+		test.Fatalf("n not equal: %d != %d ... (%d)", got, correct, len(data))
+	}
+	if err != nil {
+		test.Fatal(err)
+	}
+}
+
+func TestSkimTableComplex(test *testing.T) {
+	data := []byte {
+		7,
+		0xF3, 0xB9,
+		byte(LSI.WithCN(3)),
+		0, 0, 0, 1,
+	
+		0x01, 0x02,
+		byte(LSI.WithCN(3)),
+		0, 0, 0, 2,
+	
+		0, 0,
+		byte(SBA.WithCN(3)),
+		'h', 'i', '!',
+	
+		0xFF, 0xFF,
+		byte(OTA.WithCN(0)), 2, byte(LI.WithCN(1)),
+		0xBE, 0xE5, 0x77, 0x77,
+	
+		0x12, 0x34,
+		byte(OTA.WithCN(0)), 2, byte(OTA.WithCN(0)),
+		1, byte(LI.WithCN(1)),
+		0, 0x5,
+		2, byte(LI.WithCN(1)),
+		0,    0x17,
+		0xAA, 0xAA,
+	
+		0x23, 0x45,
+		byte(OTA.WithCN(0)), 2, byte(OTA.WithCN(0)),
+		1, byte(LSI.WithCN(1)),
+		0, 0x5,
+		2, byte(LSI.WithCN(1)),
+		0,    0x17,
+		0xF5, 0x56,
+	
+		0x34, 0x56,
+		byte(LSI.WithCN(1)),
+		0x39, 0x21,
+	}
+	mainDataLen := len(data)
+	// extra junk
+	data = append(data, 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x02, 0x03)
+
+	n, err := Skim(NewDecoder(bytes.NewBuffer(data)), KTV.WithCN(0))
+	if got, correct := n, mainDataLen; got != correct {
+		test.Fatalf("n not equal: %d != %d ... (%d)", got, correct, len(data))
+	}
+	if err != nil {
+		test.Fatal(err)
+	}
+}

tape/strings.go

@@ -0,0 +1,11 @@
+package tape
+
+const lipsum = `Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis. Tempus leo eu aenean sed diam urna tempor. Pulvinar vivamus fringilla lacus nec metus bibendum egestas. Iaculis massa nisl malesuada lacinia integer nunc posuere. Ut hendrerit semper vel class aptent taciti sociosqu. Ad litora torquent per conubia nostra inceptos himenaeos.
+
+Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis. Tempus leo eu aenean sed diam urna tempor. Pulvinar vivamus fringilla lacus nec metus bibendum egestas. Iaculis massa nisl malesuada lacinia integer nunc posuere. Ut hendrerit semper vel class aptent taciti sociosqu. Ad litora torquent per conubia nostra inceptos himenaeos.
+
+Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis. Tempus leo eu aenean sed diam urna tempor. Pulvinar vivamus fringilla lacus nec metus bibendum egestas. Iaculis massa nisl malesuada lacinia integer nunc posuere. Ut hendrerit semper vel class aptent taciti sociosqu. Ad litora torquent per conubia nostra inceptos himenaeos.
+
+Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis. Tempus leo eu aenean sed diam urna tempor. Pulvinar vivamus fringilla lacus nec metus bibendum egestas. Iaculis massa nisl malesuada lacinia integer nunc posuere. Ut hendrerit semper vel class aptent taciti sociosqu. Ad litora torquent per conubia nostra inceptos himenaeos.
+
+Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis. Tempus leo eu aenean sed diam urna tempor. Pulvinar vivamus fringilla lacus nec metus bibendum egestas. Iaculis massa nisl malesuada lacinia integer nunc posuere. Ut hendrerit semper vel class aptent taciti sociosqu. Ad litora torquent per conubia nostra inceptos himenaeos.`

tape/tag.go

@@ -0,0 +1,83 @@
+package tape
+
+import "fmt"
+
+// TODO: fix #7
+
+type Tag byte; const (
+	SI      Tag = 0 << 5 // Small integer
+	LI      Tag = 1 << 5 // Large unsigned integer
+	LSI     Tag = 2 << 5 // Large signed integer
+	FP      Tag = 3 << 5 // Floating point
+	SBA     Tag = 4 << 5 // Small byte array
+	LBA     Tag = 5 << 5 // Large byte array
+	OTA     Tag = 6 << 5 // One-tag array
+	KTV     Tag = 7 << 5 // Key-tag-value table
+	TNMask  Tag = 0xE0   // The entire TN bitfield
+	CNMask  Tag = 0x1F   // The entire CN bitfield
+	CNLimit Tag = 32     // All valid CNs are < CNLimit
+)
+
+// what the first nybble of a tag means:
+//
+//   0-1 : SI 
+//   2-3 : LI 
+//   4-5 : LSI
+//   6-7 : FP 
+//   8-9 : SBA
+//   A-B : LBA
+//   C-D : OTA
+//   E-F : KTV
+
+func (tag Tag) TN() int {
+	return int(tag >> 5)
+}
+
+func (tag Tag) CN() int {
+	return int(tag & CNMask)
+}
+
+func (tag Tag) WithCN(cn int) Tag {
+	return (tag & TNMask) | Tag(cn % 32)
+}
+
+func (tag Tag) WithoutCN() Tag {
+	return tag.WithCN(0)
+}
+
+func (tag Tag) Is(other Tag) bool {
+	return tag.TN() == other.TN()
+}
+
+func (tag Tag) String() string {
+	tn := fmt.Sprint(tag.TN())
+	switch tag.WithoutCN() {
+	case SI:  tn = "SI"
+	case LI:  tn = "LI"
+	case LSI: tn = "LSI"
+	case FP:  tn = "FP"
+	case SBA: tn = "SBA"
+	case LBA: tn = "LBA"
+	case OTA: tn = "OTA"
+	case KTV: tn = "KTV"
+	}
+	return fmt.Sprintf("%s:%d", tn, tag.CN())
+}
+
+// BufferTag returns the appropriate tag for a buffer.
+func BufferTag(value []byte) Tag {
+	return bufferLenTag(len(value))
+}
+
+// StringTag returns the appropriate tag for a string.
+func StringTag(value string) Tag {
+	return bufferLenTag(len(value))
+}
+
+func bufferLenTag(length int) Tag {
+	if length < int(CNLimit) {
+		return SBA.WithCN(length)
+	} else {
+		return LBA.WithCN(IntBytes(uint64(length)) - 1)
+	}
+}

tape/types.go

@@ -1,311 +0,0 @@
-// Package tape implements Table Pair Encoding.
-package tape
-
-import "fmt"
-
-const dataMaxSize = 0xFFFF
-const uint16Max = 0xFFFF
-
-// Error enumerates common errors in this package.
-type Error string; const (
-	ErrWrongBufferLength Error = "wrong buffer length"
-	ErrDataTooLarge      Error = "data too large"
-)
-
-// Error implements the error interface.
-func (err Error) Error() string {
-	return string(err)
-}
-
-// Int8 is any 8-bit integer.
-type Int8  interface { ~uint8  | ~int8 }
-// Int16 is any 16-bit integer.
-type Int16 interface { ~uint16 | ~int16 }
-// Int32 is any 32-bit integer.
-type Int32 interface { ~uint32 | ~int32 }
-// Int64 is any 64-bit integer.
-type Int64 interface { ~uint64 | ~int64 }
-// String is any string.
-type String interface { ~string }
-
-// DecodeI8 decodes an 8 bit integer from the given data.
-func DecodeI8[T Int8](data []byte) (T, error) {
-	if len(data) != 1 { return 0, fmt.Errorf("decoding int8: %w", ErrWrongBufferLength) }
-	return T(data[0]), nil
-}
-
-// EncodeI8 encodes an 8 bit integer into the given buffer.
-func EncodeI8[T Int8](buffer []byte, value T) error {
-	if len(buffer) != 1 { return fmt.Errorf("encoding int8: %w", ErrWrongBufferLength) }
-	buffer[0] = byte(value)
-	return nil
-}
-
-// DecodeI16 decodes a 16 bit integer from the given data.
-func DecodeI16[T Int16](data []byte) (T, error) {
-	if len(data) != 2 { return 0, fmt.Errorf("decoding int16: %w", ErrWrongBufferLength) }
-	return T(data[0]) << 8 | T(data[1]), nil
-}
-
-// EncodeI16 encodes a 16 bit integer into the given buffer.
-func EncodeI16[T Int16](buffer []byte, value T) error {
-	if len(buffer) != 2 { return fmt.Errorf("encoding int16: %w", ErrWrongBufferLength) }
-	buffer[0] = byte(value >> 8)
-	buffer[1] = byte(value)
-	return nil
-}
-
-// DecodeI32 decodes a 32 bit integer from the given data.
-func DecodeI32[T Int32](data []byte) (T, error) {
-	if len(data) != 4 { return 0, fmt.Errorf("decoding int32: %w", ErrWrongBufferLength) }
-	return T(data[0]) << 24 |
-		T(data[1]) << 16 |
-		T(data[2]) <<  8 |
-		T(data[3]), nil
-}
-
-// EncodeI32 encodes a 32 bit integer into the given buffer.
-func EncodeI32[T Int32](buffer []byte, value T) error {
-	if len(buffer) != 4 { return fmt.Errorf("encoding int32: %w", ErrWrongBufferLength) }
-	buffer[0] = byte(value >> 24)
-	buffer[1] = byte(value >> 16)
-	buffer[2] = byte(value >> 8)
-	buffer[3] = byte(value)
-	return nil
-}
-
-// DecodeI64 decodes a 64 bit integer from the given data.
-func DecodeI64[T Int64](data []byte) (T, error) {
-	if len(data) != 8 { return 0, fmt.Errorf("decoding int64: %w", ErrWrongBufferLength) }
-	return T(data[0]) << 56 |
-		T(data[1]) << 48 |
-		T(data[2]) << 40 |
-		T(data[3]) << 32 |
-		T(data[4]) << 24 |
-		T(data[5]) << 16 |
-		T(data[6]) <<  8 |
-		T(data[7]), nil
-}
-
-// EncodeI64 encodes a 64 bit integer into the given buffer.
-func EncodeI64[T Int64](buffer []byte, value T) error {
-	if len(buffer) != 8 { return fmt.Errorf("encoding int64: %w", ErrWrongBufferLength) }
-	buffer[0] = byte(value >> 56)
-	buffer[1] = byte(value >> 48)
-	buffer[2] = byte(value >> 40)
-	buffer[3] = byte(value >> 32)
-	buffer[4] = byte(value >> 24)
-	buffer[5] = byte(value >> 16)
-	buffer[6] = byte(value >> 8)
-	buffer[7] = byte(value)
-	return nil
-}
-
-// DecodeString decodes a string from the given data.
-func DecodeString[T String](data []byte) (T, error) {
-	return T(data), nil
-}
-
-// EncodeString encodes a string into the given buffer.
-func EncodeString[T String](data []byte, value T) error {
-	if len(data) != len(value) { return fmt.Errorf("encoding string: %w", ErrWrongBufferLength) }
-	copy(data, value)
-	return nil
-}
-
-// StringSize returns the size of a string. Returns 0 and an error if the size
-// is too large.
-func StringSize[T String](value T) (int, error) {
-	if len(value) > dataMaxSize { return 0, ErrDataTooLarge }
-	return len(value), nil
-}
-
-// DecodeStringArray decodes a packed string array from the given data.
-func DecodeStringArray[T String](data []byte) ([]T, error) {
-	result := []T { }
-	for len(data) > 0 {
-		if len(data) < 2 { return nil, fmt.Errorf("decoding []string: %w", ErrWrongBufferLength) }
-		itemSize16, _ := DecodeI16[uint16](data[:2])
-		itemSize := int(itemSize16)
-		data = data[2:]
-		if len(data) < itemSize { return nil, fmt.Errorf("decoding []string: %w", ErrWrongBufferLength) }
-		result = append(result, T(data[:itemSize]))
-		data = data[itemSize:]
-	}
-	return result, nil
-}
-
-// EncodeStringArray encodes a packed string array into the given buffer.
-func EncodeStringArray[T String](buffer []byte, value []T) error {
-	for _, item := range value {
-		length, err := StringSize(item)
-		if err != nil { return err }
-		if len(buffer) < 2 + length { return fmt.Errorf("encoding []string: %w", ErrWrongBufferLength) }
-		EncodeI16(buffer[:2], uint16(length))
-		buffer = buffer[2:]
-		copy(buffer, item)
-		buffer = buffer[length:]
-	}
-	if len(buffer) > 0 { return fmt.Errorf("encoding []string: %w", ErrWrongBufferLength) }
-	return nil
-}
-
-// StringArraySize returns the size of a packed string array. Returns 0 and an
-// error if the size is too large.
-func StringArraySize[T String](value []T) (int, error) {
-	total := 0
-	for _, item := range value {
-		total += 2 + len(item)
-	}
-	if total > dataMaxSize { return 0, ErrDataTooLarge }
-	return total, nil
-}
-
-// DecodeI8Array decodes a packed array of 8 bit integers from the given data.
-func DecodeI8Array[T Int8](data []byte) ([]T, error) {
-	result := make([]T, len(data))
-	for index, item := range data {
-		result[index] = T(item)
-	}
-	return result, nil
-}
-
-// EncodeI8Array encodes a packed array of 8 bit integers into the given buffer.
-func EncodeI8Array[T Int8](buffer []byte, value []T) error {
-	if len(buffer) != len(value) { return fmt.Errorf("encoding []int8: %w", ErrWrongBufferLength) }
-	for index, item := range value {
-		buffer[index] = byte(item)
-	}
-	return nil
-}
-
-// I8ArraySize returns the size of a packed 8 bit integer array. Returns 0 and
-// an error if the size is too large.
-func I8ArraySize[T Int8](value []T) (int, error) {
-	total := len(value)
-	if total > dataMaxSize { return 0, ErrDataTooLarge }
-	return total, nil
-}
-
-// DecodeI16Array decodes a packed array of 16 bit integers from the given data.
-func DecodeI16Array[T Int16](data []byte) ([]T, error) {
-	if len(data) % 2 != 0 { return nil, fmt.Errorf("decoding []int16: %w", ErrWrongBufferLength) }
-	length := len(data) / 2
-	result := make([]T, length)
-	for index := range length {
-		offset := index * 2
-		result[index] = T(data[offset]) << 8 | T(data[offset + 1])
-	}
-	return result, nil
-}
-
-// EncodeI16Array encodes a packed array of 16 bit integers into the given buffer.
-func EncodeI16Array[T Int16](buffer []byte, value []T) error {
-	if len(buffer) != len(value) * 2 { return fmt.Errorf("encoding []int16: %w", ErrWrongBufferLength) }
-	for _, item := range value {
-		buffer[0] = byte(item >> 8)
-		buffer[1] = byte(item)
-		buffer = buffer[2:]
-	}
-	return nil
-}
-
-// I16ArraySize returns the size of a packed 16 bit integer array. Returns 0 and
-// an error if the size is too large.
-func I16ArraySize[T Int16](value []T) (int, error) {
-	total := len(value) * 2
-	if total > dataMaxSize { return 0, ErrDataTooLarge }
-	return total, nil
-}
-
-// DecodeI32Array decodes a packed array of 32 bit integers from the given data.
-func DecodeI32Array[T Int32](data []byte) ([]T, error) {
-	if len(data) % 4 != 0 { return nil, fmt.Errorf("decoding []int32: %w", ErrWrongBufferLength) }
-	length := len(data) / 4
-	result := make([]T, length)
-	for index := range length {
-		offset := index * 4
-		result[index] =
-			T(data[offset + 0]) << 24 |
-			T(data[offset + 1]) << 16 |
-			T(data[offset + 2]) <<  8 |
-			T(data[offset + 3])
-	}
-	return result, nil
-}
-
-// EncodeI32Array encodes a packed array of 32 bit integers into the given buffer.
-func EncodeI32Array[T Int32](buffer []byte, value []T) error {
-	if len(buffer) != len(value) * 4 { return fmt.Errorf("encoding []int32: %w", ErrWrongBufferLength) }
-	for _, item := range value {
-		buffer[0] = byte(item >> 24)
-		buffer[1] = byte(item >> 16)
-		buffer[2] = byte(item >> 8)
-		buffer[3] = byte(item)
-		buffer = buffer[4:]
-	}
-	return nil
-}
-
-// I32ArraySize returns the size of a packed 32 bit integer array. Returns 0 and
-// an error if the size is too large.
-func I32ArraySize[T Int32](value []T) (int, error) {
-	total := len(value) * 4
-	if total > dataMaxSize { return 0, ErrDataTooLarge }
-	return total, nil
-}
-
-// DecodeI64Array decodes a packed array of 32 bit integers from the given data.
-func DecodeI64Array[T Int64](data []byte) ([]T, error) {
-	if len(data) % 8 != 0 { return nil, fmt.Errorf("decoding []int64: %w", ErrWrongBufferLength) }
-	length := len(data) / 8
-	result := make([]T, length)
-	for index := range length {
-		offset := index * 8
-		result[index] =
-			T(data[offset + 0]) << 56 |
-			T(data[offset + 1]) << 48 |
-			T(data[offset + 2]) << 40 |
-			T(data[offset + 3]) << 32 |
-			T(data[offset + 4]) << 24 |
-			T(data[offset + 5]) << 16 |
-			T(data[offset + 6]) <<  8 |
-			T(data[offset + 7])
-	}
-	return result, nil
-}
-
-// EncodeI64Array encodes a packed array of 64 bit integers into the given buffer.
-func EncodeI64Array[T Int64](buffer []byte, value []T) error {
-	if len(buffer) != len(value) * 8 { return fmt.Errorf("encoding []int64: %w", ErrWrongBufferLength) }
-	for _, item := range value {
-		buffer[0] = byte(item >> 56)
-		buffer[1] = byte(item >> 48)
-		buffer[2] = byte(item >> 40)
-		buffer[3] = byte(item >> 32)
-		buffer[4] = byte(item >> 24)
-		buffer[5] = byte(item >> 16)
-		buffer[6] = byte(item >> 8)
-		buffer[7] = byte(item)
-		buffer = buffer[8:]
-	}
-	return nil
-}
-
-// I64ArraySize returns the size of a packed 64 bit integer array. Returns 0 and
-// an error if the size is too large.
-func I64ArraySize[T Int64](value []T) (int, error) {
-	total := len(value) * 8
-	if total > dataMaxSize { return 0, ErrDataTooLarge }
-	return total, nil
-}
-
-// U16CastSafe safely casts an integer to a uint16. If an overflow or underflow
-// occurs, it will return (0, false).
-func U16CastSafe(n int) (uint16, bool) {
-	if n < uint16Max && n >= 0 {
-		return uint16(n), true
-	} else {
-		return 0, false
-	}
-}

tape/types_test.go

@@ -1,292 +0,0 @@
-package tape
-
-import "slices"
-import "errors"
-import "testing"
-import "math/rand"
-
-const largeNumberNTestRounds = 2048
-const randStringBytes        = "-abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
-
-func TestI8(test *testing.T) {
-	var buffer [16]byte
-	err := EncodeI8[uint8](buffer[:], 5)
-	if err.Error() != "encoding int8: wrong buffer length" { test.Fatal(err) }
-	err = EncodeI8[uint8](buffer[:0], 5)
-	if err.Error() != "encoding int8: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI8[uint8](buffer[:])
-	if err.Error() != "decoding int8: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI8[uint8](buffer[:0])
-	if err.Error() != "decoding int8: wrong buffer length" { test.Fatal(err) }
-	
-	for number := range uint8(255) {
-		err := EncodeI8[uint8](buffer[:1], number)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI8[uint8](buffer[:1])
-		if err != nil { test.Fatal(err) }
-		if decoded != number {
-			test.Fatalf("%d != %d", decoded, number)
-		}
-	}
-}
-
-func TestI16(test *testing.T) {
-	var buffer [16]byte
-	err := EncodeI16[uint16](buffer[:], 5)
-	if err.Error() != "encoding int16: wrong buffer length" { test.Fatal(err) }
-	err = EncodeI16[uint16](buffer[:0], 5)
-	if err.Error() != "encoding int16: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI16[uint16](buffer[:])
-	if err.Error() != "decoding int16: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI16[uint16](buffer[:0])
-	if err.Error() != "decoding int16: wrong buffer length" { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		number := uint16(rand.Int())
-		err := EncodeI16[uint16](buffer[:2], number)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI16[uint16](buffer[:2])
-		if err != nil { test.Fatal(err) }
-		if decoded != number {
-			test.Fatalf("%d != %d", decoded, number)
-		}
-	}
-}
-
-func TestI32(test *testing.T) {
-	var buffer [16]byte
-	err := EncodeI32[uint32](buffer[:], 5)
-	if err.Error() != "encoding int32: wrong buffer length" { test.Fatal(err) }
-	err = EncodeI32[uint32](buffer[:0], 5)
-	if err.Error() != "encoding int32: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI32[uint32](buffer[:])
-	if err.Error() != "decoding int32: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI32[uint32](buffer[:0])
-	if err.Error() != "decoding int32: wrong buffer length" { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		number := uint32(rand.Int())
-		err := EncodeI32[uint32](buffer[:4], number)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI32[uint32](buffer[:4])
-		if err != nil { test.Fatal(err) }
-		if decoded != number {
-			test.Fatalf("%d != %d", decoded, number)
-		}
-	}
-}
-
-func TestI64(test *testing.T) {
-	var buffer [16]byte
-	err := EncodeI64[uint64](buffer[:], 5)
-	if err.Error() != "encoding int64: wrong buffer length" { test.Fatal(err) }
-	err = EncodeI64[uint64](buffer[:0], 5)
-	if err.Error() != "encoding int64: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI64[uint64](buffer[:])
-	if err.Error() != "decoding int64: wrong buffer length" { test.Fatal(err) }
-	_, err = DecodeI64[uint64](buffer[:0])
-	if err.Error() != "decoding int64: wrong buffer length" { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		number := uint64(rand.Int())
-		err := EncodeI64[uint64](buffer[:8], number)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI64[uint64](buffer[:8])
-		if err != nil { test.Fatal(err) }
-		if decoded != number {
-			test.Fatalf("%d != %d", decoded, number)
-		}
-	}
-}
-
-func TestString(test *testing.T) {
-	var buffer [16]byte
-	err := EncodeString[string](buffer[:], "hello")
-	if !errIs(err, ErrWrongBufferLength, "encoding string: wrong buffer length") { test.Fatal(err) }
-	err = EncodeString[string](buffer[:0], "hello")
-	if !errIs(err, ErrWrongBufferLength, "encoding string: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeString[string](buffer[:])
-	if err != nil { test.Fatal(err) }
-	_, err = DecodeString[string](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		length := rand.Intn(16)
-		str := randString(length)
-		err := EncodeString[string](buffer[:length], str)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeString[string](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if decoded != str {
-			test.Fatalf("%s != %s", decoded, str)
-		}
-	}
-}
-
-func TestI8Array(test *testing.T) {
-	var buffer [64]byte
-	err := EncodeI8Array[uint8](buffer[:], []uint8 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int8: wrong buffer length") { test.Fatal(err) }
-	err = EncodeI8Array[uint8](buffer[:0], []uint8 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int8: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeI8Array[uint8](buffer[:])
-	if err != nil { test.Fatal(err) }
-	_, err = DecodeI8Array[uint8](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		array := randInts[uint8](rand.Intn(16))
-		length, _ := I8ArraySize(array)
-		if length != len(array) { test.Fatalf("%d != %d", length, len(array)) }
-		err := EncodeI8Array[uint8](buffer[:length], array)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI8Array[uint8](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if !slices.Equal(decoded, array) {
-			test.Fatalf("%v != %v", decoded, array)
-		}
-	}
-}
-
-func TestI16Array(test *testing.T) {
-	var buffer [128]byte
-	err := EncodeI16Array[uint16](buffer[:], []uint16 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int16: wrong buffer length") { test.Fatal(err) }
-	err = EncodeI16Array[uint16](buffer[:0], []uint16 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int16: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeI16Array[uint16](buffer[:])
-	if err != nil { test.Fatal(err) }
-	_, err = DecodeI16Array[uint16](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		array := randInts[uint16](rand.Intn(16))
-		length, _ := I16ArraySize(array)
-		if length != 2 * len(array) { test.Fatalf("%d != %d", length, 2 * len(array)) }
-		err := EncodeI16Array[uint16](buffer[:length], array)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI16Array[uint16](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if !slices.Equal(decoded, array) {
-			test.Fatalf("%v != %v", decoded, array)
-		}
-	}
-}
-
-func TestI32Array(test *testing.T) {
-	var buffer [256]byte
-	err := EncodeI32Array[uint32](buffer[:], []uint32 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int32: wrong buffer length") { test.Fatal(err) }
-	err = EncodeI32Array[uint32](buffer[:0], []uint32 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int32: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeI32Array[uint32](buffer[:])
-	if err != nil { test.Fatal(err) }
-	_, err = DecodeI32Array[uint32](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		array := randInts[uint32](rand.Intn(16))
-		length, _ := I32ArraySize(array)
-		if length != 4 * len(array) { test.Fatalf("%d != %d", length, 4 * len(array)) }
-		err := EncodeI32Array[uint32](buffer[:length], array)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI32Array[uint32](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if !slices.Equal(decoded, array) {
-			test.Fatalf("%v != %v", decoded, array)
-		}
-	}
-}
-
-func TestI64Array(test *testing.T) {
-	var buffer [512]byte
-	err := EncodeI64Array[uint64](buffer[:], []uint64 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int64: wrong buffer length") { test.Fatal(err) }
-	err = EncodeI64Array[uint64](buffer[:0], []uint64 { 0, 4, 50, 19 })
-	if !errIs(err, ErrWrongBufferLength, "encoding []int64: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeI64Array[uint64](buffer[:])
-	if err != nil { test.Fatal(err) }
-	_, err = DecodeI64Array[uint64](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		array := randInts[uint64](rand.Intn(16))
-		length, _ := I64ArraySize(array)
-		if length != 8 * len(array) { test.Fatalf("%d != %d", length, 8 * len(array)) }
-		err := EncodeI64Array[uint64](buffer[:length], array)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeI64Array[uint64](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if !slices.Equal(decoded, array) {
-			test.Fatalf("%v != %v", decoded, array)
-		}
-	}
-}
-
-func TestStringArray(test *testing.T) {
-	var buffer [8192]byte
-	err := EncodeStringArray[string](buffer[:], []string { "0", "4", "50", "19" })
-	if !errIs(err, ErrWrongBufferLength, "encoding []string: wrong buffer length") { test.Fatal(err) }
-	err = EncodeStringArray[string](buffer[:0], []string { "0", "4", "50", "19" })
-	if !errIs(err, ErrWrongBufferLength, "encoding []string: wrong buffer length") { test.Fatal(err) }
-	_, err = DecodeStringArray[string](buffer[:0])
-	if err != nil { test.Fatal(err) }
-	
-	for _ = range largeNumberNTestRounds {
-		array := randStrings[string](rand.Intn(16), 16)
-		length, _ := StringArraySize(array)
-		// TODO test length
-		err := EncodeStringArray[string](buffer[:length], array)
-		if err != nil { test.Fatal(err) }
-		decoded, err := DecodeStringArray[string](buffer[:length])
-		if err != nil { test.Fatal(err) }
-		if !slices.Equal(decoded, array) {
-			test.Fatalf("%v != %v", decoded, array)
-		}
-	}
-}
-
-func TestU16CastSafe(test *testing.T) {
-	number, ok := U16CastSafe(90_000)
-	if ok { test.Fatalf("false positive: %v, %v", number, ok) }
-	number, ok = U16CastSafe(-478)
-	if ok { test.Fatalf("false positive: %v, %v", number, ok) }
-	number, ok = U16CastSafe(3870)
-	if !ok { test.Fatalf("false negative: %v, %v", number, ok) }
-	if got, correct := number, uint16(3870); got != correct {
-		test.Fatalf("not equal: %v %v", got, correct)
-	}
-	number, ok = U16CastSafe(0)
-	if !ok { test.Fatalf("false negative: %v, %v", number, ok) }
-	if got, correct := number, uint16(0); got != correct {
-		test.Fatalf("not equal: %v %v", got, correct)
-	}
-}
-
-func randString(length int) string {
-	buffer := make([]byte, length)
-	for index := range buffer {
-		buffer[index] = randStringBytes[rand.Intn(len(randStringBytes))]
-	}
-	return string(buffer)
-}
-
-func randInts[T interface { ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 }] (length int) []T {
-	buffer := make([]T, length)
-	for index := range buffer {
-		buffer[index] = T(rand.Int())
-	}
-	return buffer
-}
-
-func randStrings[T interface { ~string }] (length, maxItemLength int) []T {
-	buffer := make([]T, length)
-	for index := range buffer {
-		buffer[index] = T(randString(rand.Intn(maxItemLength)))
-	}
-	return buffer
-}
-
-func errIs(err error, wraps error, description string) bool {
-	return err != nil && (wraps == nil || errors.Is(err, wraps)) && err.Error() == description
-}