coreutils

// basename.c, version 1.0.1

// OMKOV coreutils implementation of POSIX basename

// Copyright (C) 2020, Jakob Wakeling

// MIT Licence

#include "util/error.h"

#include "util/optget.h"

#include <stdio.h>

#define VERSION "1.0.1"

static struct lop lops[] = {

	{ "help",    ARG_NUL, 256 },

	{ "version", ARG_NUL, 257 },

	{ NULL, 0, 0 }

};

static void hlp(void);

static void ver(void);

int main(int ac, char *av[]) { A0 = av[0];

	struct opt opt = OPTGET_INIT; opt.str = ""; opt.lops = lops;

	for (int o; (o = optget(&opt, av, 1)) != -1;) switch (o) {

	case 256: { hlp(); return 0; }

	case 257: { ver(); return 0; }

	default: { return 1; }

	}

	if (opt.ind == ac) { error(1, "missing operand"); }

	register char *p = av[opt.ind];

	// If the string is empty, print "."

	if (!*p) { fputc('.', stdout); fputc('\n', stdout); return 0; }

	// From the end of the string, move left to the first non '/' character

	for (++p; *p; ++p) {} for (--p; *p == '/'; --p);

	// If the string contains only '/' characters, print "/"

	if (p + 1 == av[opt.ind]) { fputs("/\n", stdout); return 0; }

	else { p[1] = 0; } // Otherwise remove the trailing '/' characters

	if (av[opt.ind + 1]) { // If a suffix operand is provided

		register char *s = av[opt.ind + 1]; for (; *s; ++s);

		// Move left through string and suffix as long as they are the same

		for (--s; *p && *p != '/' && *s && *p == *s; --p, --s);

		// If the suffix is matched completely and characters remain in the

		// string without it, remove the suffix from the string

		if (!*s && *p && *p != '/') { p[1] = 0; }

	}

	// Move pointer left until the start of the string or '/' is found and print

	for (; *p && *p != '/'; --p) {} fputs(p + 1, stdout); fputc('\n', stdout);

	return 0;

}

/* Print help information */

static void hlp(void) {

	puts("basename - return the non-directory portion of a path\n");

	puts("usage: basename string [suffix]\n");

	puts("options:");

	puts("  --help     Display help information");

	puts("  --version  Display version information");

}

/* Print version information */

static void ver(void) {

	puts("OMKOV coreutils basename, version " VERSION);

	puts("Copyright (C) 2020, Jakob Wakeling");

	puts("MIT Licence (https://opensource.org/licenses/MIT)");

}