/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef XPG4
#include <unistd.h>
#include <regex.h>
#include <libintl.h>
#endif

int
main(int argc, char **argv)
{
        char    *p;
        char    *string;
        char    *suffix;
#ifndef XPG4
        int     r;
        char    suf_buf[256];
        char    *suf_pat;
        size_t  suf_len;
        regex_t reg;
        regmatch_t      pmatch[2];
#endif

        /*
         * For better performance, defer the setlocale()/textdomain()
         * calls until they get really required.
         */
#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"
#endif
        if (argc == 1) {
                (void) puts(".");
                return (0);
        }

#ifdef  XPG4
        if (strcmp(argv[1], "--") == 0) {
                argv++;
                argc--;
                if (argc == 1) {
                        (void) puts(".");
                        return (0);
                }
        }
#endif
        if (argc > 3) {
                (void) setlocale(LC_ALL, "");
                (void) textdomain(TEXT_DOMAIN);
                (void) fputs(gettext("Usage: basename string [ suffix ]\n"),
                    stderr);
                return (1);
        }

        string = argv[1];
        suffix = (argc == 2) ? NULL : argv[2];

        if (*string == '\0') {
                (void) puts(".");
                return (0);
        }

        /* remove trailing slashes */
        p = string + strlen(string) - 1;
        while (p >= string && *p == '/')
                *p-- = '\0';

        if (*string == '\0') {
                (void) puts("/");
                return (0);
        }

        /* skip to one past last slash */
        if ((p = strrchr(string, '/')) != NULL)
                string = p + 1;

        if (suffix == NULL) {
                (void) puts(string);
                return (0);
        }

#ifdef  XPG4
        /*
         * if a suffix is present and is not the same as the remaining
         * string and is identical to the last characters in the remaining
         * string, remove those characters from the string.
         */
        if (strcmp(string, suffix) != 0) {
                p = string + strlen(string) - strlen(suffix);
                if (strcmp(p, suffix) == 0)
                        *p = '\0';
        }
        (void) puts(string);
        return (0);
#else
        (void) setlocale(LC_ALL, "");
        (void) textdomain(TEXT_DOMAIN);

        suf_len = 6 + strlen(suffix) + 1 + 1; /* \(.*\)suffix$ */
        if (suf_len > sizeof (suf_buf)) {
                suf_pat = malloc(suf_len);
                if (suf_pat == NULL) {
                        (void) fputs("malloc failed\n", stderr);
                        return (1);
                }
        } else {
                suf_pat = suf_buf;
        }
        (void) strcpy(suf_pat, "\\(.*\\)");
        (void) strcpy(suf_pat + 6, suffix);
        *(suf_pat + suf_len - 1 - 1) = '$';
        *(suf_pat + suf_len - 1) = '\0';

        r = regcomp(&reg, suf_pat, 0);
        if (r != 0) {
                (void) fprintf(stderr,
                    "Internal error: regcomp failed for \"%s\"\n",
                    suf_pat);
                return (1);
        }
        r = regexec(&reg, string, 2, pmatch, 0);
        if (r == 0) {
                if (pmatch[0].rm_so == (regoff_t)-1 ||
                    pmatch[1].rm_so == (regoff_t)-1 ||
                    pmatch[1].rm_so != 0) {
                        (void) fprintf(stderr, "Internal error: regexec did "
                            "not set sub-expression for:\n");
                        (void) fprintf(stderr, "path: \"%s\"\n", string);
                        (void) fprintf(stderr, "pattern: \"%s\"", suf_pat);
                        return (1);
                }
                if (pmatch[1].rm_so == pmatch[1].rm_eo) {
                        /* a null string matched */
                        (void) printf("%s\n", string);
                        return (0);
                }
                string[pmatch[1].rm_eo] = '\0';
        }
        (void) puts(string);
        return (0);
#endif
}