101 lines
2.9 KiB
Go
101 lines
2.9 KiB
Go
package codec
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import "io"
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// Decoder wraps an [io.Reader] and decodes data from it.
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type Decoder struct {
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io.Reader
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}
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// ReadFull calls [io.ReadFull] on the reader.
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func (this *Decoder) ReadFull(buffer []byte) (n int, err error) {
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return io.ReadFull(this, buffer)
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}
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// ReadByte decodes a single byte from the input reader.
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func (this *Decoder) ReadByte() (value byte, n int, err error) {
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uncasted, n, err := this.ReadUint8()
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return byte(uncasted), n, err
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}
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// ReadInt8 decodes an 8-bit signed integer from the input reader.
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func (this *Decoder) ReadInt8() (value int8, n int, err error) {
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uncasted, n, err := this.ReadUint8()
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return int8(uncasted), n, err
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}
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// ReadUint8 decodes an 8-bit unsigned integer from the input reader.
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func (this *Decoder) ReadUint8() (value uint8, n int, err error) {
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buffer := [1]byte { }
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n, err = this.ReadFull(buffer[:])
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return uint8(buffer[0]), n, err
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}
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// ReadInt16 decodes an 16-bit signed integer from the input reader.
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func (this *Decoder) ReadInt16() (value int16, n int, err error) {
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uncasted, n, err := this.ReadUint16()
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return int16(uncasted), n, err
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}
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// ReadUint16 decodes an 16-bit unsigned integer from the input reader.
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func (this *Decoder) ReadUint16() (value uint16, n int, err error) {
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buffer := [2]byte { }
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n, err = this.ReadFull(buffer[:])
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return uint16(buffer[0]) << 8 |
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uint16(buffer[1]), n, err
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}
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// ReadInt32 decodes an 32-bit signed integer from the input reader.
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func (this *Decoder) ReadInt32() (value int32, n int, err error) {
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uncasted, n, err := this.ReadUint32()
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return int32(uncasted), n, err
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}
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// ReadUint32 decodes an 32-bit unsigned integer from the input reader.
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func (this *Decoder) ReadUint32() (value uint32, n int, err error) {
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buffer := [4]byte { }
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n, err = this.ReadFull(buffer[:])
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return uint32(buffer[0]) << 24 |
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uint32(buffer[1]) << 16 |
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uint32(buffer[2]) << 8 |
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uint32(buffer[3]), n, err
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}
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// ReadInt64 decodes an 64-bit signed integer from the input reader.
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func (this *Decoder) ReadInt64() (value int64, n int, err error) {
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uncasted, n, err := this.ReadUint64()
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return int64(uncasted), n, err
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}
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// ReadUint64 decodes an 64-bit unsigned integer from the input reader.
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func (this *Decoder) ReadUint64() (value uint64, n int, err error) {
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buffer := [8]byte { }
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n, err = this.ReadFull(buffer[:])
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return uint64(buffer[0]) << 56 |
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uint64(buffer[1]) << 48 |
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uint64(buffer[2]) << 48 |
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uint64(buffer[3]) << 32 |
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uint64(buffer[4]) << 24 |
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uint64(buffer[5]) << 16 |
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uint64(buffer[6]) << 8 |
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uint64(buffer[7]), n, err
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}
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// ReadGBEU decodes a growing unsigned integer of up to 64 bits from the input
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// reader.
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func (this *Decoder) ReadGBEU() (value uint64, n int, err error) {
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var fullValue uint64
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for {
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chunk, nn, err := this.ReadByte()
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if err != nil { return 0, n, err }
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n += nn
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fullValue *= 0x80
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fullValue += uint64(chunk & 0x7F)
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ccb := chunk >> 7
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if ccb == 0 {
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return fullValue, n, nil
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}
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}
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}
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