Merge branch 'dj-formatting'

I could trace strcmp(1) as far back as
<293436c5ad/src/streq.c>
in my repo.

Makefile

@@ -109,13 +109,13 @@ build/bin/hru: src/hru.rs build rustlibs
 
 .PHONY: intcmp
 intcmp: build/bin/intcmp
-build/bin/intcmp: src/intcmp.c build
-	$(CC) $(CFLAGS) -o $@ src/intcmp.c
+build/bin/intcmp: src/intcmp.rs build rustlibs
+	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/intcmp.rs
 
 .PHONY: mm
 mm: build/bin/mm
-build/bin/mm: src/mm.c build
-	$(CC) $(CFLAGS) -o $@ src/mm.c
+build/bin/mm: src/mm.rs build rustlibs 
+	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/mm.rs
 
 .PHONY: npc
 npc: build/bin/npc

STYLE

@@ -65,7 +65,7 @@ opening curly brace and before a closing one:
 8. If a control flow statement is short enough to be easily understood in a
 glance, it may be placed on a single line:
 
-	if (!argc < 0) { usage(program_name); }
+	if !(argc < 0) { usage(program_name); }
 
 9. In C, note everything you use from a library in a comment subsequent to its
 #include statement:
@@ -86,21 +86,29 @@ library crates. Group alike statements:
 
 11. Do not use do while loops in C.
 
-12. Follow the rules from the paper The Power of 10: Rules for Developing
-Safety-Critical Code [0]:
+12. Adhere to the following rules from the paper The Power of 10: Rules for
+Developing Safety-Critical Code [0]:
 	1. Avoid complex flow constructs, such as goto and recursion.
 	2. All loops must have fixed bounds. This prevents runaway code.
 	3. Avoid heap memory allocation.
-	4. Restrict functions to a single printed page.
-	5. Use a minimum of two runtime assertions per function.
+	4. Restrict functions to the length of a single printed page.
+
 	6. Restrict the scope of data to the smallest possible.
 	7. Check the return value of all non-void functions, or cast to void to
-	indicate the return value is useless.
+	indicate the return value is useless (such as in the case of using
+	fprintf(3p)	to print to the standard error).
 	8. Use the preprocessor sparingly.
 	9. Limit pointer use to a single dereference, and do not use function
 	pointers.
 	10. Compile with all possible warnings active; all warnings should then be
-	addressed before release of the software.
+	addressed before release of the software (for C compilers, compile with
+	-Wpedantic).
+
+13. Remember this quote from The Elements of Programming Style by Brian
+Kernighan:
+	Everyone knows that debugging is twice as hard as writing a program in the
+	first place. So if you're as clever as you can be when you write it, how
+	will you ever debug it?
 
 
 References

docs/mm.1

@@ -3,14 +3,14 @@
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
 .\"
-.TH MM 1 2024-06-17 "Harakit X.X.X"
+.TH MM 1 2024-07-14 "Harakit X.X.X"
 .SH NAME
 mm \(en middleman
 .\"
 .SH SYNOPSIS
 
 mm
-.RB [ -aenu ]
+.RB [ -aetu ]
 .RB [ -i\ input ]
 .RB [ -o\ output ]
 .\"
@@ -21,19 +21,25 @@ Catenate input files and write them to the start of each output file or stream.
 .SH OPTIONS
 
 .IP \fB-a\fP
-Opens subsequent outputs for appending rather than updating.
+Opens outputs for appending rather than updating.
 .IP \fB-e\fP
 Use the standard error as an output.
-.IP \fB-i\fP\ \fIinput\fP
-Opens a path as an input. If one or more of the input files is \(lq-\(rq or if
-no inputs are specified, the standard input shall be used.
-.IP \fB-o\fP\ \fIoutput\fP
-Opens a path as an output. If one or more of the output files is \(lq-\(rq or if
-no outputs are specified, the standard output shall be used.
+.IP \fB-t\fP
+Causes outputs to be overwritten instead of being truncated.
 .IP \fB-u\fP
 Ensures neither input or output will be buffered.
-.IP \fB-n\fP
-Causes SIGINT signals to be ignored.
+.IP \fB-i\fP\ \fIinput\fP
+Opens a path as an input. If one or more of the input files is \(lq-\(rq or if
+no inputs are specified, the standard input shall be used. If specified as the
+last option and if there are trailing arguments to the program, they shall be
+appended to the list of files to use as inputs.
+.IP \fB-o\fP\ \fIoutput\fP
+Opens a path as an output. If one or more of the output files is \(lq-\(rq or if
+no outputs are specified and the
+.B -e
+option is not specified, the standard output shall be used. If specified as the
+last option and if there are trailing arguments to the program, they shall be
+appended to the list of files to use as outputs.
 .\"
 .SH DIAGNOSTICS
 
@@ -45,10 +51,6 @@ exits with the appropriate
 .BR sysexits.h (3)
 status.
 .\"
-.SH CAVEATS
-
-Existing files are not truncated on ouput and are instead overwritten.
-.\"
 .SH RATIONALE
 
 The

docs/strcmp.1

@@ -4,7 +4,7 @@
 .\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
 .\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
 .\"
-.TH STRCMP 1 2024-06-17 "Harakit X.X.X"
+.TH STRCMP 1 2024-07-15 "Harakit X.X.X"
 .SH NAME
 strcmp \(en compare strings
 .\"
@@ -20,15 +20,15 @@ Check whether string arguments are the same.
 .SH DIAGNOSTICS
 
 The program will exit successfully if the strings are identical. Otherwise, it
-will exit with an error code of 1 if a string passed has a lesser byte value
-than one of the prior strings:
+will exit with an error code less than 128 if a string passed has a lesser byte
+value than one of the prior strings:
 
 .RS
 strcmp b a
 .RE
 
-or with an error code of 255 if it has a greater byte value than one of the
-prior strings:
+or with an error code greater than 128 if it has a greater byte value than one
+of the prior strings:
 
 .RS
 strcmp a b

docs/swab.1

@@ -11,7 +11,6 @@ swab \(en swap bytes
 .SH SYNOPSIS
 
 swab
-.RB [ -f ]
 .RB [ -w\ word_size ]
 .\"
 .SH DESCRIPTION
@@ -20,8 +19,6 @@ Swap the latter and former halves of a block of bytes.
 .\"
 .SH OPTIONS
 
-.IP \fB-f\fP
-Ignore SIGINT signal.
 .IP \fB-w\fP\ \fIword_size\fP
 Configures the word size; that is, the size in bytes of the block size on which
 to operate. The default word size is 2. The word size must be cleanly divisible

src/dj.c

@@ -20,6 +20,7 @@
 #include <assert.h> /* assert(3) */
 #include <errno.h> /* errno */
 #include <fcntl.h> /* open(2) */
+#include <stdbool.h> /* bool */
 #include <stdio.h> /* fprintf(3), stderr */
 #include <stdlib.h> /* malloc(3), strtol(3), size_t */
 #include <string.h> /* memcpy(3), memmove(3), memset(3) */
@@ -28,8 +29,6 @@
                      * optarg, optind, STDIN_FILENO, STDOUT_FILENO */
 #include <sys/stat.h> /* S_IRGRP, S_IROTH, S_IRUSR, S_IWGRP, S_IWOTH, S_IWUSR */
 
-extern int errno;
-
 char *program_name = "dj";
 
 /* dj uses two structures that respectively correspond to the reading and
@@ -49,10 +48,6 @@ struct Io {
 	int fl;         /* file opening flags */
 };
 
-/* To be assigned to main:fmt and used with printio(). */
-static char *fmt_asv   = "%d\037%d\036%d\037%d\035%d\036%d\034";
-static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
-
 static char *stdin_name = "<stdin>";
 static char *stdout_name = "<stdout>";
 
@@ -66,6 +61,7 @@ static int write_flags = O_WRONLY | O_CREAT;
 /* Macro to check if fd is stdin or stdout */
 #define fdisstd(fd) ((fd) == STDIN_FILENO || (fd) == STDOUT_FILENO)
 
+/* Completes one Io block read */
 static struct Io *
 Io_read(struct Io *io) {
 	int t;
@@ -88,6 +84,7 @@ Io_read(struct Io *io) {
 	return io;
 }
 
+/* Completes one Io block write */
 static struct Io *
 Io_write(struct Io *io) {
 	int t;
@@ -99,7 +96,7 @@ Io_write(struct Io *io) {
 		io->error = errno;
 		t = 0;
 	} else if (t > 0) {
-		memmove(io->buf, &(io->buf)[t], (io->bufuse -= t));
+		(void)memmove(io->buf, &(io->buf)[t], (io->bufuse -= t));
 	}
 
 	io->bytes += t;
@@ -111,15 +108,16 @@ Io_write(struct Io *io) {
 
 static int
 oserr(char *e, int n) {
-	fprintf(stderr, "%s: %s: %s\n", program_name, e, strerror(n));
+	(void)fprintf(stderr, "%s: %s: %s\n", program_name, e, strerror(n));
+
 	return EX_OSERR;
 }
 
 /* Prints statistics regarding the use of dj, particularly partially and
  * completely read and written records. */
-static void
+static int
 fprintio(FILE *stream, char *fmt, struct Io io[2]) {
-	fprintf(
+	return fprintf(
 		stream,
 		fmt,
 		io[0].rec,
@@ -129,10 +127,20 @@ fprintio(FILE *stream, char *fmt, struct Io io[2]) {
 		io[0].bytes,
 		io[1].bytes
 	);
-
-	return;
 }
 
+/* To be assigned to main:fmt and used with printio(). */
+static char *fmt_asv =
+	"%d" /* io[0].rec   */ "\037" /* ASCII US */
+	"%d" /* io[0].prec  */ "\036" /* ASCII RS */
+	"%d" /* io[1].rec   */ "\037" /* ASCII US */
+	"%d" /* io[1].prec  */ "\035" /* ASCII GS */
+	"%d" /* io[0].bytes */ "\036" /* ASCII RS */
+	"%d" /* io[1].bytes */ "\034" /* ASCII FS */
+	"\n"
+;
+static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
+
 /* Parses the string s to an integer, returning either the integer or in the
  * case of an error a negative integer. This is used for argument parsing
  * (e.g. -B [int]) in dj and no negative integer would be valid anyway. */
@@ -146,11 +154,13 @@ parse(char *s) {
 }
 
 static int
-usage(char *s) {
-	fprintf(
-		stderr, "Usage: %s [-Hn] [-a byte] [-c count]\n"
+usage(char *argv0) {
+	(void)fprintf(
+		stderr,
+		"Usage: %s [-Hn] [-a byte] [-c count]\n"
 		"\t[-i file] [-b block_size] [-s offset]\n"
-		"\t[-o file] [-B block_size] [-S offset]\n", program_name
+		"\t[-o file] [-B block_size] [-S offset]\n",
+		argv0
 	);
 
 	return EX_USAGE;
@@ -158,17 +168,17 @@ usage(char *s) {
 
 int main(int argc, char *argv[]) {
    	int align;    /* low 8b used, negative if no alignment is being done */
-	int count;    /* 0 if dj(1) runs until no more reads are possible */
-	char *fmt;    /* == fmt_asv (default) or fmt_human (-H) */
-	size_t i;     /* side of io being modified */
-	char noerror; /* 0=exits (default) 1=retries on partial reads or writes */
+	int count;    /* -1 if dj(1) runs until no more reads are possible */
+	char *fmt;    /* set to fmt_asv (default) or fmt_human (-H) */
+	size_t i;     /* side of io (in or out) being modified */
+	bool retry;   /* false if exits on partial reads or writes */
 	struct Io io[2 /* { in, out } */];
 
 	/* Set defaults. */
 	align = -1;
-	count = 0;
+	count = -1;
 	fmt = fmt_asv;
-	noerror = 0;
+	retry = 0;
 	for (i = 0; i < (sizeof io) / (sizeof *io); ++i) {
 		io[i].bs = 1024 /* 1 KiB */; /* GNU dd(1) default; POSIX says 512B */
 		io[i].bufuse = 0;
@@ -209,8 +219,9 @@ int main(int argc, char *argv[]) {
 						}
 					}
 
-					return oserr(optarg, errno); /* break; */
-				case 'n': noerror = 1; break; /* retry failed reads once */
+					return oserr(optarg, errno);
+					/* UNREACHABLE */
+				case 'n': retry = 1; break; /* retry failed reads once */
 				case 'H': fmt = fmt_human; break; /* human-readable output */
 				case 'a': /* input buffer padding */
 					if (optarg[0] == '\0' || optarg[1] == '\0') {
@@ -224,12 +235,12 @@ int main(int argc, char *argv[]) {
 					if (c == 'c' && (count = parse(optarg)) >= 0) { break; }
 
 					i = (c >= 'A' && c <= 'Z');
-					c |= 0x20; /* 0b 0010 0000 (ASCII make lowercase) */
+					c |= 0x20; /* 0b 0010 0000 (ASCII) make lowercase */
 
-					if (
+					if ( /* if -b or -s is parsed out correctly */
 						(c == 'b' && (io[i].bs = parse(optarg)) > 0)
 						|| (c == 's' && (io[i].seek = parse(optarg)) >= 0)
-					) { break; }
+					) { break; } /* don't error */
 
 					/* FALLTHROUGH */
 				default:
@@ -246,7 +257,7 @@ int main(int argc, char *argv[]) {
 	for (i = 0; i < (sizeof io) / (sizeof *io); ++i) {
 		/* buffer allocation */
 		if ((io[i].buf = malloc(io[i].bs * (sizeof *(io[i].buf)))) == NULL) {
-			fprintf(
+			(void)fprintf(
 				stderr, "%s: Failed to allocate %zd bytes\n",
 				program_name, io[i].bs
 			);
@@ -263,13 +274,13 @@ int main(int argc, char *argv[]) {
 
 	/* hard seeking; t is io[1].bufuse, before Io_write subtracts from it */
 	for(size_t t; io[1].seek > 0; io[1].seek -= (t - io[1].bufuse)) {
-		memset(
+		(void)memset(
 			io[1].buf, '\0', /* set buf to all nulls */
 			(t = io[1].bufuse = MIN(io[1].bs, io[1].seek)) /* saturate block */
 		);
 
-		if (Io_write(&io[1])->bufuse == t && !noerror && io[1].error == 0) {
-			Io_write(&io[1]); /* second chance */
+		if (Io_write(&io[1])->bufuse == t && !retry && io[1].error == 0) {
+			(void)Io_write(&io[1]); /* second chance */
 		}
 
 		if (io[1].error != 0) { return oserr(io[1].fn, io[1].error); }
@@ -277,14 +288,17 @@ int main(int argc, char *argv[]) {
 		if (io[1].bufuse == t) { break; } /* all writes failed! */
 	}
 
-	io[1].bufuse = 0;
+	io[1].bufuse = 0; /* reset after hard seek */
 
 	if (io[1].seek > 0) { /* hard seeking failed */
-		fprintio(stderr, fmt, io);
+		(void)fprintio(stderr, fmt, io);
 		return oserr(io[1].fn, errno);
 	}
 
-	do { /* while(count == 0 || --count > 0); */
+	for (	;
+			count == -1 || count > 0;
+			count -= (count != -1) /* decrement if counting */
+	) {
 		assert(io[0].bufuse == 0);
 
 		{ /* read */
@@ -297,23 +311,23 @@ int main(int argc, char *argv[]) {
 			}
 
 			t = io[0].bufuse;
-			if (Io_read(&io[0])->bufuse == t && !noerror && io[0].error == 0) {
-				Io_read(&io[0]); /* second chance */
+			if (Io_read(&io[0])->bufuse == t && !retry && io[0].error == 0) {
+				(void)Io_read(&io[0]); /* second chance */
 			}
 
 			assert(io[0].bufuse >= t);
 
-			if (io[0].bufuse == t) /* that's all she wrote */ { break; }
+			if (io[0].bufuse == t) { break; } /* that's all she wrote */
 
 			if (/* t < io[0].bufuse && */ io[0].bufuse < io[0].bs) {
-				fprintf(stderr, "%s: Partial read:\n\t", program_name);
-				fprintio(stderr, fmt, io);
+				(void)fprintf(stderr, "%s: Partial read:\n\t", program_name);
+				(void)fprintio(stderr, fmt, io);
 
-				if (!noerror) { count = 1; }
+				if (!retry) { count = 1; }
 
 				if (align >= 0) {
 					/* fill the rest of the ibuf with padding */
-					memset(
+					(void)memset(
 						&(io[0].buf)[io[0].bufuse],
 						align,
 						io[0].bs - io[0].bufuse
@@ -326,7 +340,7 @@ int main(int argc, char *argv[]) {
 			if (skipping > 0) {
 				io[0].seek -= skipping;
 				io[0].bufuse = 0;
-				count += (count != 0);
+				count += (count != -1); /* increment if counting */
 				continue;
 			}
 		}
@@ -337,25 +351,25 @@ int main(int argc, char *argv[]) {
 			if (io[0].bs <= io[1].bs) {
 				int n;
 
-				memcpy( /* saturate obuf */
+				(void)memcpy( /* saturate obuf */
 					io[1].buf, io[0].buf,
 				   (io[1].bufuse = (n = MIN(io[0].bufuse, io[1].bs)))
 				);
 
 				/* permute the copied units out of ibuf */
-				memmove(io[0].buf, &(io[0].buf)[n], (io[0].bufuse -= n));
+				(void)memmove(io[0].buf, &(io[0].buf)[n], (io[0].bufuse -= n));
 			} else /* if(io[0].bs > io[1].bs) */ {
 				int n;
 
 				/* drain what we can from ibuf */
-				memcpy(
+				(void)memcpy(
 					&(io[1].buf)[io[1].bufuse], io[0].buf,
 				    (n = MIN(io[0].bufuse, io[1].bs - io[1].bufuse))
 				);
 				io[1].bufuse += n;
 
 				/* permute out the copied units */
-				memmove(io[0].buf, &(io[0].buf)[n], io[0].bs - n);
+				(void)memmove(io[0].buf, &(io[0].buf)[n], io[0].bs - n);
 				io[0].bufuse -= n;
 
 				if(io[0].bs + io[1].bufuse <= io[1].bs && count != 1) {
@@ -368,9 +382,9 @@ int main(int argc, char *argv[]) {
 
 				t = io[1].bufuse;
 				if (Io_write(&io[1])->bufuse == t
-						&& !noerror
+						&& !retry
 						&& io[1].error == 0) {
-					Io_write(&io[1]); /* second chance */
+					(void)Io_write(&io[1]); /* second chance */
 				}
 
 				assert(io[1].error == 0 || io[1].bufuse == t);
@@ -387,15 +401,15 @@ int main(int argc, char *argv[]) {
 			}
 
 			if (0 < io[1].bufuse /* && io[1].bufuse < t */) {
-				fprintf(stderr, "%s: Partial write:\n\t", program_name);
-				fprintio(stderr, fmt, io);
+				(void)fprintf(stderr, "%s: Partial write:\n\t", program_name);
+				(void)fprintio(stderr, fmt, io);
 
-				if(!noerror) { count = 1; }
+				if(!retry) { count = 1; }
+			}
 		}
 	}
-	} while(count == 0 || --count > 0);
 
-	fprintio(stderr, fmt, io);
+	(void)fprintio(stderr, fmt, io);
 
 	for (i = 0; i < (sizeof io) / (sizeof *io); ++i) {
 		if (io[i].error) { return oserr(io[i].fn, io[i].error); }

src/fop.rs

@@ -33,7 +33,7 @@ use sysexits::{ EX_DATAERR, EX_IOERR, EX_UNAVAILABLE, EX_USAGE };
 fn main() {
 	let argv = args().collect::<Vec<String>>();
 	let mut d = '\u{1E}'.to_string(); /* ASCII record separator */
-	let mut optind = 0;
+	let mut optind = 1;
 
 	let usage = format!(
 		"Usage: {} [-d delimiter] index command [args...]",
@@ -42,18 +42,24 @@ fn main() {
 
 	while let Some(opt) = argv.getopt("d:") {
 		match opt.opt() {
-			Ok(_) => {
+			Ok("d") => {
 				/* delimiter */
 				d = opt.arg().unwrap();
 				optind = opt.ind();
 			},
-			Err(_) => {
+			_ => {
 				eprintln!("{}", usage);
 				exit(EX_USAGE);
 			}
 		};
 	}
 
+	/* parse the specified index as a number we can use */
+	let index = argv[optind].parse::<usize>().unwrap_or_else(|e| {
+		eprintln!("{}: {}: {}", argv[0], argv[1], e);
+		exit(EX_DATAERR);
+	});
+
 	/* index of the argv[0] for the operator command */
 	let command_arg = optind as usize + 1;
 
@@ -63,20 +69,18 @@ fn main() {
 		exit(EX_USAGE);
 	});
 
-	/* parse the specified index as a number we can use */
-	let index = argv[optind].parse::<usize>().unwrap_or_else(|e| {
-		eprintln!("{}: {}: {}", argv[0], argv[1], e);
-		exit(EX_DATAERR);
-	});
-
+	/* read entire standard input into memory */
 	let mut buf = String::new();
-	let _ = stdin().read_to_string(&mut buf);
+	if let Err(e) = stdin().read_to_string(&mut buf) {
+		eprintln!("{}: {}", argv[0], e.strerror());
+		exit(EX_IOERR);
+	};
 
 	/* split the buffer by the delimiter (by default, '\u{1E}') */
 	let mut fields = buf.split(&d).collect::<Vec<&str>>();
 
 	/* collect arguments for the operator command */
-	let opts = argv
+	let command_args = argv
 		.iter()
 		.clone()
 		.skip(command_arg + 1) /* skip the command name */
@@ -84,7 +88,7 @@ fn main() {
 
 	/* spawn the command to operate on the field */
 	let mut spawned = Command::new(operator)
-		.args(opts) /* spawn with the specified arguments */
+		.args(command_args) /* spawn with the specified arguments */
 		.stdin(Stdio::piped())
 		.stdout(Stdio::piped()) /* piped stdout to handle output ourselves */
 		.spawn()
@@ -117,8 +121,13 @@ fn main() {
 	/* get the output with which the original field will be replaced */
 	let mut replace = output.stdout.clone();
 
-	/* as long as it’s not a newline, set the replacement to the output */
-	if replace.pop() != Some(b'\n') { replace = output.stdout; }
+	/* pop trailing newline out if the input did not contain it */
+	if fields[index].chars().last() != Some('\n') /* no newline */
+		&& replace.pop() != Some(b'\n') { /* pop last char of replacement */
+		/* restore replacement to original command output if popped char was not
+		 * a newline */
+		replace = output.stdout;
+	}
 
 	/* convert the output of the program to UTF-8 */
 	let new_field = String::from_utf8(replace).unwrap_or_else(|e| {

src/intcmp.c

@@ -1,87 +0,0 @@
-/*
- * Copyright (c) 2023 DTB <trinity@trinity.moe>
- * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
- * SPDX-License-Identifier: AGPL-3.0-or-later
- *
- * This program is free software: you can redistribute it and/or modify it under
- * the terms of the GNU Affero General Public License as published by the Free
- * Software Foundation, either version 3 of the License, or (at your option) any
- * later version.
- * 
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
- * details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see https://www.gnu.org/licenses/.
- */
-
-#include <errno.h> /* errno */
-#include <stdio.h> /* fprintf(3), stderr */
-#include <stdlib.h> /* strtol(3), size_t, EXIT_FAILURE */
-#include <unistd.h> /* getopt(3), optind */
-#include <sysexits.h> /* EX_OK, EX_USAGE */
-
-/* 0b00? */		/*         Equal                       | -e  | 0b001 | 1 */
-#define EQUAL	0x01	/* Greater                     | -g  | 0b010 | 2 */
-/* 0b0?0 */		/*         Greater or Equal            | -ge | 0b011 | 3 */
-#define GREATER	0x02	/* Lesser                      | -l  | 0b100 | 4 */
-/* 0b?00 */		/*         Lesser or Equal             | -le | 0b101 | 5 */
-#define LESSER	0x04	/* Inequal (Greater or Lesser) | -gl | 0b110 | 6 */
-
-static char *program_name = "intcmp";
-
-int usage(char *s) {
-	fprintf(stderr, "Usage: %s [-egl] integer integer...\n", s);
-
-	return EX_USAGE;
-}
-
-int main(int argc, char *argv[]) {
-	int c;
-	size_t i;
-	unsigned char mode;
-	int r; /* reference integer */
-	char *s = (argv[0] == NULL ? program_name : argv[0]);
-
-	mode = 0;
-
-	if (argc == 0 | argc < 3) { return usage(s); }
-
-	while ((c = getopt(argc, argv, "egl")) != -1) {
-		switch (c) {
-			case 'e': mode |= EQUAL;   break;
-			case 'g': mode |= GREATER; break;
-			case 'l': mode |= LESSER;  break;
-			default:  return usage(s);
-		}
-	}
-
-	if (optind + 2 /* ref cmp */ > argc) { return usage(s); }
-
-	i = optind;
-
-	do {
-		r = c;
-		c = strtol(argv[i], &argv[i], 10);
-
-		if (*argv[i] != '\0' || errno != 0) {
-			fprintf(
-				stderr, "%s: argument #%d: Invalid integer\n", argv[0], (int)i
-			);
-			return EX_USAGE;
-		}
-
-		if (i == optind) { continue; }
-
-		/* rule enforcement; if a mode isn't permitted and the numbers
-		 * correspond to it, return 1 */
-		if (   (!(mode & EQUAL) && r == c)
-			|| (!(mode & GREATER) && r > c)
-			|| (!(mode & LESSER) && r < c)
-		) { return 1; }
-	} while (++i < argc);
-	
-	return EX_OK;
-}

src/intcmp.rs

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2023–2024 DTB <trinity@trinity.moe>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+use std::{
+	env::args,
+	process::ExitCode
+};
+
+extern crate getopt;
+use getopt::GetOpt;
+
+extern crate sysexits;
+use sysexits::EX_USAGE;
+
+fn usage(s: &str) -> ExitCode {
+	eprintln!("Usage: {} [-egl] integer integer...", s);
+	ExitCode::from(EX_USAGE as u8)
+}
+
+fn main() -> ExitCode {
+	let argv = args().collect::<Vec<String>>();
+	let mut e = false; /* args can be == */
+	let mut g = false; /* args can be > */
+	let mut l = false; /* args can be < */
+	let mut optind = 0;
+
+	if argv.len() < 3 { return usage(&argv[0]); }
+
+	while let Some(opt) = argv.getopt("egl") {
+		match opt.opt() {
+			Ok("e") => e = true,
+			Ok("g") => g = true,
+			Ok("l") => l = true,
+			_ => { return usage(&argv[0]); },
+		}
+		optind = opt.ind();
+	}
+
+	if argv.len() - optind < 2 /* see usage */ { return usage(&argv[0]); }
+
+	let mut prev: Option<usize> = None; /* no previous operand */
+	let mut currn: usize;
+
+	for arg in argv.iter().skip(optind) { /* iterate operands */
+		match arg.parse::<usize>() { /* parse current operand */
+			Ok(n) => currn = n,
+			_ => {
+				eprintln!("{}: {}: Invalid integer", &argv[0], arg);
+				return ExitCode::from(EX_USAGE as u8);
+			}
+		}
+
+		if let Some(prevn) = prev { /* if there was a previous opr., test */
+			if (!e && prevn == currn)
+					|| (!g && prevn > currn)
+					|| (!l && prevn < currn)
+				{ return ExitCode::FAILURE; }
+		}
+
+		prev = Some(currn); /* there is a previous operand */
+	}
+
+	ExitCode::SUCCESS
+}

src/mm.c

@@ -1,268 +0,0 @@
-/*
- * Copyright (c) 2024 DTB <trinity@trinity.moe>
- * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
- * SPDX-License-Identifier: AGPL-3.0-or-later
- *
- * This program is free software: you can redistribute it and/or modify it under
- * the terms of the GNU Affero General Public License as published by the Free
- * Software Foundation, either version 3 of the License, or (at your option) any
- * later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
- * details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see https://www.gnu.org/licenses/.
- */
-
-#include <errno.h> /* errno */
-#include <signal.h> /* signal(2), SIG_ERR, SIG_IGN, SIGINT */
-#include <stdio.h> /* fclose(3), fopen(3), fprintf(3), getc(3), putc(3),
-                    * setvbuf(3), size_t, _IONBF, NULL */
-#include <stdlib.h> /* free(3), realloc(3) */
-#include <string.h> /* strcmp(3), strerror(3) */
-#include <unistd.h> /* getopt(3) */
-#include <sysexits.h> /* EX_IOERR, EX_OK, EX_OSERR, EX_USAGE */
-
-extern int errno;
-
-/* This structure is how open files are tracked. */
-struct Files{
-	size_t a;	/* allocation */
-	size_t s;	/* used size */
-	char *mode;	/* file opening mode */
-	char **names;	/* file names */
-	FILE **files;	/* file pointers */
-};
-
-/* How much to grow the allocation when it's saturated. */
-#ifndef ALLOC_INCREMENT
-#	define ALLOC_INCREMENT 1
-#endif
-
-/* How much to grow the allocation at program start. */
-#ifndef ALLOC_INITIAL
-#	define ALLOC_INITIAL 10
-#endif
-
-/* pre-allocated strings */
-static char *program_name = "<no argv[0]>";
-static char *stdin_name = "<stdin>";
-static char *stdout_name = "<stdout>";
-static char *stderr_name = "<stderr>";
-static char *(fmode[]) = { (char []){"rb"}, (char []){"rb+"} };
-static char *wharsh = "wb";
-
-/* Adds the open FILE pointer for the file at the path s to the files struct,
- * returning the FILE if successful and NULL if not, allocating more memory in
- * the files buffers as needed. */
-static FILE *
-Files_append(struct Files *files, FILE *file, char *name) {
-
-	if (file == NULL || (files->s == files->a
-			&& ((files->files = realloc(files->files,
-					(files->a += (files->a == 0)
-						? ALLOC_INITIAL
-						: ALLOC_INCREMENT)
-					* sizeof *(files->files))) == NULL
-				|| (files->names = realloc(files->names,
-					files->a * sizeof *(files->names))) == NULL)))
-		return NULL;
-
-	files->names[files->s] = name;
-	return files->files[files->s++] = file;
-}
-
-/* Opens the file at the path p and puts it in the files struct, returning NULL
- * if either the opening or the placement of the open FILE pointer fail. */
-#define Files_open(files, p) \
-	Files_append((files), fopen((p), (files)->mode), (p))
-
-/* Prints a diagnostic message based on errno and returns an exit status
- * appropriate for an OS error. */
-static int
-oserr(char *s, char *r) {
-
-	fprintf(stderr, "%s: %s: %s\n", s, r, strerror(errno));
-
-	return EX_OSERR;
-}
-
-/* Hijacks i and j from main and destructs the files[2] struct used by main by
- * closing its files and freeing its files and names arrays, returning retval
- * from main. */
-#define terminate \
-	for (i = 0; i < 2; ++i) { \
-		for (j = 0; j < files[i].s; ++j) { \
-			if ( \
-				files[i].files[j] != stdin \
-				&& files[i].files[j] != stdout \
-				&& files[i].files[j] != stderr \
-			) { \
-				fclose(files[i].files[j]); \
-			} \
-		} \
-		free(files[i].files); \
-		free(files[i].names); \
-	} \
-	return retval
-
-/* Prints a usage text, in which s is the program being run (i.e. argv[0]), and
- * returns an exit status appropriate for a usage error. */
-int usage(char *s) {
-
-	fprintf(stderr, "Usage: %s [-aenu] [-i input]... [-o output]...\n", s);
-
-	return EX_USAGE;
-}
-
-int main(int argc, char *argv[]) {
-	int c;
-	struct Files files[2]; /* {read, write} */
-	size_t i;
-	size_t j;
-	size_t k; /* loop index but also unbuffer status */
-	int retval;
-
-	/* Initializes the files structs with their default values, standard
-	 * input and standard output. If an input or an output is specified
-	 * these initial values will be overwritten, so to, say, use mm(1)
-	 * equivalently to tee(1p), -o - will need to be specified before
-	 * additional files to ensure standard output is still written. */
-	for (i = 0; i < 2; ++i) {
-		files[i].a = 0;
-		files[i].s = 0;
-		files[i].mode = fmode[i];
-		files[i].files = NULL;
-		files[i].names = NULL;
-
-		Files_append(
-			&files[i],
-			i == 0 ? stdin : stdout,
-			i == 0 ? stdin_name : stdout_name
-		);
-
-		files[i].s = 0;
-	}
-
-	k = 0;
-
-	if (argc > 0) { program_name = argv[0]; }
-
-	if (argc > 1) {
-		while ((c = getopt(argc, argv, "aehi:no:u")) != -1) {
-			switch (c){
-				case 'a': /* "rb+" -> "ab" */
-					files[1].mode[0] = 'a';
-					files[1].mode[2] = '\0';
-					break;
-				case 'e':
-					if (Files_append(&files[1], stderr, stderr_name) != NULL) {
-						break;
-					}
-
-					retval = oserr(argv[0], "-e");
-					terminate;
-				case 'i':
-					if (
-						(strcmp(optarg, "-") == 0
-						&& Files_append(&files[0], stdin, stdin_name) != NULL)
-						|| Files_open(&files[0], optarg) != NULL
-					) { break; }
-
-					retval = oserr(argv[0], optarg);
-					terminate;
-				case 'o':
-					if (
-						(strcmp(optarg, "-") == 0
-						&& Files_append(&files[1], stdout, stdout_name) != NULL)
-						|| Files_open(&files[1], optarg) != NULL
-					) { break; }
-					/* does not exist, so try to create it */
-					if (errno == ENOENT) {
-						files[1].mode = wharsh;
-
-						if (Files_open(&files[1], optarg) != NULL) {
-							files[1].mode = fmode[1];
-							break;
-						}
-					}
-
-					retval = oserr(argv[0], optarg);
-					terminate;
-				case 'n':
-					if (signal(SIGINT, SIG_IGN) != SIG_ERR) { break; }
-
-					retval = oserr(argv[0], "-n");
-					terminate;
-				case 'u':
-					k = 1;
-					break;
-				default:
-					retval = usage(argv[0]);
-					terminate;
-			}
-		}
-	}
-
-	if (optind != argc) {
-		retval = usage(argv[0]);
-		terminate;
-	}
-
-	files[0].s += files[0].s == 0;
-	files[1].s += files[1].s == 0;
-	
-	/* Unbuffer files. */
-	if (k) {
-		for (
-			i = 0; i < files[0].s; setvbuf(files[0].files[i++], NULL, _IONBF, 0)
-		);
-		for (
-			i = 0; i < files[1].s; setvbuf(files[1].files[i++], NULL, _IONBF, 0)
-		);
-	}
-
-	retval = EX_OK;
-
-	/* Actual program loop. */
-	for (i = 0; i < files[0].s; ++i) { /* iterate ins */
-		while ((c = getc(files[0].files[i])) != EOF) { /* iterate chars */
-			for (j = 0; j < files[1].s; ++j) { /* iterate outs */
-				if (putc(c, files[1].files[j]) == EOF) {
-					/* notebook's full */
-					retval = EX_IOERR;
-					fprintf(
-						stderr,
-						"%s: %s: %s\n",
-						program_name,
-						files[1].names[j],
-						strerror(errno)
-					);
-
-					if (fclose(files[1].files[j]) == EOF) {
-						fprintf(
-							stderr,
-							"%s: %s: %s\n",
-							program_name,
-							files[1].names[j],
-							strerror(errno)
-						);
-					}
-
-					/* massage out the tense muscle */
-					for(k = j--; k < files[1].s - 1; ++k){
-						files[1].files[k] = files[1].files[k+1];
-						files[1].names[k] = files[1].names[k+1];
-					}
-
-					if(--files[1].s == 0) { terminate; }
-				}
-			}
-		}
-	}
-
-	terminate;
-}

src/mm.rs

@@ -0,0 +1,185 @@
+/*
+ * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
+ * Copyright (c) 2024 DTB <trinity@trinity.moe>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option) any
+ * later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+use std::{
+	env::args,
+	fs::File,
+	io::{ stdin, stdout, stderr, BufWriter, Read, Write },
+	os::fd::{ AsRawFd, FromRawFd },
+	process::{ exit, ExitCode },
+};
+
+extern crate getopt;
+extern crate strerror;
+extern crate sysexits;
+
+use getopt::GetOpt;
+use strerror::StrError;
+use sysexits::{ EX_IOERR, EX_USAGE };
+
+use ArgMode::*;
+
+enum ArgMode { In, Out }
+
+fn main() -> ExitCode {
+	let argv = args().collect::<Vec<_>>();
+	let usage = format!("Usage: {} [-aetu] [-i input] [-o output]", argv[0]);
+
+	let mut a = false; /* append to the file */
+	let mut e = false; /* use stderr as an output */
+	let mut t = true; /* do not truncate the file before writing */
+	let mut u = false; /* unbuffer i/o */
+	let mut ins = Vec::new(); /* initial input file path vector */
+	let mut outs = Vec::new(); /* initial output file path vector */
+	let mut mode: Option<ArgMode> = None; /* mode set by last-used option */
+	let mut optind = 0;
+
+	while let Some(opt) = argv.getopt("aei:o:tu") {
+		match opt.opt() {
+			Ok("a") => a = true,
+			Ok("e") => e = true, 
+			Ok("u") => u = true,
+			Ok("t") => t = false,
+			Ok("i") => { /* add inputs */
+				let input = opt.arg().unwrap();
+				ins.push(input);
+				mode = Some(In); /* latest argument == -i */
+			},
+			Ok("o") => { /* add output */
+				let output = opt.arg().unwrap(); 
+				outs.push(output);
+				mode = Some(Out); /* latest argument == -o */
+			},
+			Err(_) | Ok(_) => {
+				eprintln!("{}", usage);
+				return ExitCode::from(EX_USAGE as u8);
+			},
+		};
+
+		optind = opt.ind();
+	}
+
+	let remaining = argv.iter().skip(optind);
+
+	/* check the last flag specified */
+	if let Some(m) = mode {
+		for arg in remaining {
+			/* move the subsequent arguments to the list of inputs or outputs */
+			match m {
+				In => ins.push(arg.to_string()),
+				Out => outs.push(arg.to_string()),
+			};
+		}
+	} else {
+		eprintln!("{}", usage);
+		return ExitCode::from(EX_USAGE as u8);
+	}
+
+	/* use stdin if no inputs are specified */
+	if ins.is_empty() { ins.push("-".to_string()); }
+
+	/* use stdout if no outputs are specified */
+	if outs.is_empty() && !e { outs.push("-".to_string()); }
+	
+	/* map all path strings to files */
+	let inputs = ins.iter().map(|file| {
+		/* if a file is “-”, it is stdin */
+		if *file == "-" {
+			/* portable way to access stdin as a file */
+			return unsafe { File::from_raw_fd(stdin().as_raw_fd()) };
+		}
+
+		match File::open(file) {
+			Ok(f) => f,
+			Err(e) => {
+				eprintln!("{}: {}: {}", argv[0], file, e.strerror());
+				exit(EX_IOERR);
+			},
+		}
+	}).collect::<Vec<_>>();
+
+	/* map all path strings to files */
+	let mut outputs = outs.iter().map(|file| {
+		/* of a file is “-”, it is stdout */
+		if *file == "-" {
+			/* portable way to access stdout as a file */
+			return unsafe { File::from_raw_fd(stdout().as_raw_fd()) }; 
+		}
+
+		let options = File::options()
+			/* don’t truncate if -t is specified, append if -a is specified */
+			.truncate(t)
+			.append(a)
+			/* enable the ability to create and write to files */
+			.create(true)
+			.write(true)
+			/* finally, open the file! */
+			.open(file);
+
+		match options {
+			Ok(f) => return f,
+			Err(e) => {
+				eprintln!("{}: {}: {}", argv[0], file, e.strerror());
+				exit(EX_IOERR);
+			},
+		};
+	}).collect::<Vec<_>>();
+
+	/* if -e is specified, use stderr */
+	if e {
+		/* portable way to access stderr as a file */
+		outputs.push(unsafe { File::from_raw_fd(stderr().as_raw_fd()) });
+	}
+
+	let mut outputs = outputs.iter().map(|o| {
+		if u {
+			/* unbuffered writing through a buffer of capacity 0 */
+			BufWriter::with_capacity(0, o)
+		} else {
+			/* theoretically buffered writing */
+			BufWriter::new(o)
+		}
+	}).collect::<Vec<_>>();
+
+	for file in inputs {
+		for byte in file.bytes().map(|b| {
+			b.unwrap_or_else(|e| {
+				eprintln!("{}: {}", argv[0], e.strerror());
+				exit(EX_IOERR);
+			})
+		}) {
+			for out in &mut outputs {
+				if let Err(e) = out.write(&[byte]) {
+					eprintln!("{}: {}", argv[0], e.strerror());
+					return ExitCode::from(EX_IOERR as u8);
+				}
+
+				if u {
+					/* immediately flush the output for -u */
+					if let Err(e) = out.flush() { 
+						eprintln!("{}: {}", argv[0], e.strerror());
+						return ExitCode::from(EX_IOERR as u8);
+					}
+				}
+			}
+		}
+	}
+
+	ExitCode::SUCCESS
+}

src/npc.c

@@ -17,14 +17,24 @@
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
 
-#include <stdio.h> /* fprintf(3), fputs(3), getc(3), putc(3), stdin, stdout,
-                    * EOF */
-#include <stdlib.h> /* EXIT_FAILURE */
+#include <stdio.h> /* fprintf(3), fputs(3), getc(3), perror(3), putc(3), stdin,
+                    * stdout, EOF */
+#include <sysexits.h> /* EX_IOERR, EX_OK, EX_USAGE */
 #include <unistd.h> /* getopt(3) */
-#include <sysexits.h> /* EX_OK, EX_USAGE */
 
-int usage(char *s) {
-	fprintf(stderr, "Usage: %s [-et]\n", s);
+char *program_name = "npc";
+
+static int
+ioerr(char *argv0) {
+	perror(argv0);
+
+	return EX_IOERR;
+}
+
+static int
+usage(char *argv0) {
+	(void)fprintf(stderr, "Usage: %s [-et]\n", argv0);
+
 	return EX_USAGE;
 }
 
@@ -34,28 +44,37 @@ int main(int argc, char *argv[]) {
 	char showtab = 0; /* prints tab characters in caret notation */
 
 	if (argc > 0) {
+		program_name = argv[0];
+
 		while ((c = getopt(argc, argv, "et")) != -1) {
 			switch (c){
 				case 'e': showend = 1; break;
 				case 't': showtab = 1; break;
-				default:  return usage(argv[0]);
+				default:  return usage(program_name);
 			}
 		}
 	}
 
-	if (argc > optind) { return usage(argv[0]); }
+	if (argc > optind) { return usage(program_name); }
 
 	while ((c = getc(stdin)) != EOF) {
-		if ((c & 0x80) != 0) { fputs("M-", stdout); }
+		if ((c & 0x80) != 0 && fputs("M-", stdout) == EOF) {
+			return ioerr(argv[0]);
+		}
 
 		switch (c ^ 0x80 /* 0b 1000 0000 */) {
-			case 0x7f: fputs("^?", stdout); break; /* delete character */
-			case '\n': if (showend) { putc('$', stdout); }
+			case 0x7f: /* ASCII DEL (127d) */
+				if(fputs("^?", stdout) == EOF) { return ioerr(argv[0]); }
+				break;
+			case '\n':
+				if (showend && fputc('$', stdout) == EOF) {
+					return ioerr(argv[0]);
+				}
 			default:
 				if (c >= ' ' || c == '\n' || (!showtab && c == '\t')) {
-					putc(c, stdout);
-				} else {
-					fprintf(stdout, "^%c", c + '@');
+					if (fputc(c, stdout) == EOF) { return ioerr(argv[0]); }
+				} else if (fprintf(stdout, "^%c", c + '@') < 0) {
+					return ioerr(argv[0]);
 				}
 		}
 	}

src/scrut.c

@@ -26,87 +26,69 @@
                        * S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
                        * S_ISUID, S_ISVTX */
 
-static char args[] = "bcdefghkprsuwxLS";
-static char ops[(sizeof args) / (sizeof *args)];
-static char *program_name = "scrut";
+char *program_name = "scrut";
+#define OPTS "bcdefgkprsuwxLS"
+static char *opts = OPTS;
 
-int usage(char *s) {
-	fprintf(
-		stderr,
-		"Usage: %s [-%s] file...\n",
-		s == NULL ? program_name : s, args
-	);
+static int
+usage(char *argv0) {
+	(void)fprintf(stderr, "Usage: %s [-" OPTS "] file...\n", argv0);
 
 	return EX_USAGE;
 }
 
 int main(int argc, char *argv[]) {
-	struct stat buf;
-	int c;
-	size_t i;
+	char sel[(sizeof opts) / (sizeof *opts)];
+
+	if (argc < 2) { return usage(argv[0] == NULL ? program_name : argv[0]); }
+
+	{ /* option parsing */
 		char *p;
 
-	if (argc < 2) { return usage(argv[0]); }
-
-	memset(ops, '\0', sizeof ops);
-	while ((c = getopt(argc, argv, args)) != -1) {
-		if ((p = strchr(args, c)) == NULL) {
-			return usage(argv[0]);
-		} else {
-			ops[p - args] = c;
-		}
+		memset(sel, '\0', sizeof sel);
+		for (int c; (c = getopt(argc, argv, opts)) != -1;) {
+			if ((p = strchr(opts, c)) == NULL) { return usage(argv[0]); }
+			else { sel[p - opts] = c; }
 		}
 
-	/* straighten out ops */
-	for (i = 0, p = ops; i < (sizeof ops) / (sizeof *ops); ++i) {
-		if (ops[i] != '\0') {
-			*p = ops[i];
-			if (&ops[i] != p++) { ops[i] = '\0'; }
+		/* straighten out selections; permute out nulls */
+		p = sel;
+		for (size_t i = 0; i < (sizeof sel) / (sizeof *sel); ++i) {
+			if (sel[i] != '\0') {
+				*p = sel[i];
+				if (&sel[i] != p++) { sel[i] = '\0'; }
+			}
 		}
 	}
 
 	if (optind == argc) { return usage(argv[0]); }
 
-	argv += optind;
-	do { /* while(*++argv != NULL); */
+	for (argv += optind ; *argv != NULL; ++argv) {
+		struct stat buf;
+
 		if(access(*argv, F_OK) != 0 || lstat(*argv, &buf) == -1) {
 			return EXIT_FAILURE; /* doesn't exist or isn't stattable */
 		}
 
-		for (i = 0; ops[i] != '\0'; ++i)
-			if (ops[i] == 'e') {
-				continue;
-			} else if (ops[i] == 'h') {
-				return usage(argv[0]);
-			} else if (
-					(ops[i] == 'b'
-						&& !S_ISBLK(buf.st_mode))
-					|| (ops[i] == 'c'
-						&& !S_ISCHR(buf.st_mode))
-					|| (ops[i] == 'd'
-						&& !S_ISDIR(buf.st_mode))
-					|| (ops[i] == 'f'
-						&& !S_ISREG(buf.st_mode))
-					|| (ops[i] == 'g'
-						&& !(buf.st_mode & S_ISGID))
-					|| (ops[i] == 'k'
-						&& !(buf.st_mode & S_ISVTX))
-					|| (ops[i] == 'p'
-						&& !S_ISFIFO(buf.st_mode))
-					|| (ops[i] == 'r'
-						&& access(*argv, R_OK) != 0)
-					|| (ops[i] == 'u'
-						&& !(buf.st_mode & S_ISUID))
-					|| (ops[i] == 'w'
-						&& access(*argv, W_OK) != 0)
-					|| (ops[i] == 'x'
-						&& access(*argv, X_OK) != 0)
-					|| (ops[i] == 'L'
-						&& !S_ISLNK(buf.st_mode))
-					|| (ops[i] == 'S'
-						&& !S_ISSOCK(buf.st_mode))
+		for (size_t i = 0; sel[i] != '\0'; ++i) {
+			if (
+					(sel[i] == 'b' && !S_ISBLK(buf.st_mode))
+					|| (sel[i] == 'c' && !S_ISCHR(buf.st_mode))
+					|| (sel[i] == 'd' && !S_ISDIR(buf.st_mode))
+					|| (sel[i] == 'e' && 0)
+					|| (sel[i] == 'f' && !S_ISREG(buf.st_mode))
+					|| (sel[i] == 'g' && !(buf.st_mode & S_ISGID))
+					|| (sel[i] == 'k' && !(buf.st_mode & S_ISVTX))
+					|| (sel[i] == 'p' && !S_ISFIFO(buf.st_mode))
+					|| (sel[i] == 'r' && access(*argv, R_OK) != 0)
+					|| (sel[i] == 'u' && !(buf.st_mode & S_ISUID))
+					|| (sel[i] == 'w' && access(*argv, W_OK) != 0)
+					|| (sel[i] == 'x' && access(*argv, X_OK) != 0)
+					|| (sel[i] == 'L' && !S_ISLNK(buf.st_mode))
+					|| (sel[i] == 'S' && !S_ISSOCK(buf.st_mode))
 			) { return EXIT_FAILURE; }
-	} while(*++argv != NULL);
+		}
+	}
 
 	return EXIT_SUCCESS;
 }

src/str.c

@@ -45,14 +45,16 @@ static struct {
 	{ NULL, NULL } /* marks end */
 };
 
-int usage(char *s){
-	fprintf(stderr, "Usage: %s type string...\n", s);
+static int
+usage(char *argv0) {
+	(void)fprintf(stderr, "Usage: %s type string...\n", argv0);
+
 	return EX_USAGE;
 }
 
 int main(int argc, char *argv[]) {
-	size_t ctype; /* selected from ctypes.h; index of ctype */
-	int retval;
+	size_t ctype; // selected from ctypes.h; index of ctype
+	int retval; // initially fail but becomes success on the first valid char
 
 	if (argc < 3) { return usage(argv[0] == NULL ? program_name : argv[0]); }
 
@@ -71,7 +73,8 @@ int main(int argc, char *argv[]){
 			/* First checks if argv[0][i] is valid ASCII; ctypes(3) don't
 			 * handle non-ASCII. This is bad. */
 			if(
-				(unsigned char)argv[0][i] < 0x80 && !ctypes[ctype].f(argv[0][i])
+				(unsigned char)argv[0][i] < 0x80 // argv[0][i] is ASCII,
+					&& !ctypes[ctype].f(argv[0][i]) // so use ctypes(3)
 			) { return EXIT_FAILURE; }
 			else { retval = EXIT_SUCCESS; }
 		}

src/strcmp.c

@@ -16,17 +16,16 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
-
 #include <stdio.h> /* fprintf(3), stderr */
 #include <sysexits.h> /* EX_OK, EX_USAGE */
 
-static char *program_name = "strcmp";
+char *program_name = "strcmp";
 
 int main(int argc, char *argv[]) {
 	int i;
 
 	if (argc < 3) {
-		fprintf(
+		(void)fprintf(
 			stderr,
 			"Usage: %s string string...\n",
 			argv[0] == NULL ? program_name : argv[0]

src/swab.rs

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2024 DTB <trinity@trinity.moe>
+ * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * This program is free software: you can redistribute it and/or modify it under
@@ -18,72 +19,78 @@
 
 use std::{
 	env::args,
-	io::{ stdin, stdout, Error, ErrorKind, Read, Write },
+	io::{ stdin, stdout, Error, Read, Write },
 	process::ExitCode,
 	vec::Vec
 };
 
 extern crate getopt;
-use getopt::GetOpt;
-
 extern crate sysexits;
-use sysexits::{ EX_OK, EX_OSERR, EX_USAGE };
-
 extern crate strerror;
+
+use getopt::GetOpt;
+use sysexits::{ EX_IOERR, EX_OK, EX_OSERR, EX_USAGE };
 use strerror::StrError;
 
-fn oserr(s: &str, e: Error) -> ExitCode {
-	eprintln!("{}: {}", s, e.strerror());
+fn oserr(argv0: &str, e: Error) -> ExitCode {
+	eprintln!("{}: {}", argv0, e.strerror());
 	ExitCode::from(EX_OSERR as u8)
 }
 
+fn ioerr(argv0: &str, e: Error) -> ExitCode {
+	eprintln!("{}: {}", argv0, e.strerror());
+	ExitCode::from(EX_IOERR as u8)
+}
+
 fn usage(s: &str) -> ExitCode {
-	eprintln!("Usage: {} [-f] [-w word_size]", s);
+	eprintln!("Usage: {} [-w word_size]", s);
 	ExitCode::from(EX_USAGE as u8)
 }
 
 fn main() -> ExitCode {
 	let argv = args().collect::<Vec<String>>();
-	let mut buf: Vec<u8> = Vec::new();
+	let mut buf: Vec<u8> = Vec::new(); // holds the sequence getting swabbed
 	let mut input = stdin();
 	let mut output = stdout().lock();
+	let mut optind: usize = 1;   // argv[0]
+	let mut wordsize: usize = 2; // default; mimics dd(1p) conv=swab
 
-	let mut force = false;
-	let mut wordsize: usize = 2;
-
-	while let Some(opt) = argv.getopt("fw:") {
+	while let Some(opt) = argv.getopt("w:") {
 		match opt.opt() {
-			Ok("f") => force = true,
 			Ok("w") => {
-				if let Some(arg) = opt.arg() {
-					match arg.parse::<usize>() {
-						Ok(w) if w % 2 == 0 => { wordsize = w; () },
+					match opt.arg().unwrap().parse::<usize>() {
+						Ok(w) if w % 2 == 0 => { wordsize = w; },
 						_ => { return usage(&argv[0]); },
 					}
-				}
+				optind = opt.ind();
 			},
 			_ => { return usage(&argv[0]); }
 		}
 	}
 
+	if optind < argv.len() {
+		return usage(&argv[0]);
+	}
+
 	buf.resize(wordsize, 0);
 
 	loop {
 		match input.read(&mut buf) {
-			Ok(0) => break ExitCode::from(EX_OK as u8),
-			Ok(v) if v == wordsize => {
+			Ok(0) => break ExitCode::from(EX_OK as u8), // read nothing; bye
+			Ok(v) if v == wordsize => { // read full block; swab
 				let (left, right) = buf.split_at(v/2);
+
 				if let Err(e) = output.write(&right)
 						.and_then(|_| output.write(&left)) {
-					break oserr(&argv[0], e)
+					break ioerr(&argv[0], e);
 				}
+
 			},
-			Ok(v) => {
+			Ok(v) => { // partial read; partially write
 				if let Err(e) = output.write(&buf[..v]) {
-					break oserr(&argv[0], e)
+					break ioerr(&argv[0], e);
 				}
 			},
-			Err(e) if e.kind() == ErrorKind::Interrupted && force => continue,
 			Err(e) => break oserr(&argv[0], e)
 		}
 	}