libcmd/common/dirname.c

	dirname.c revision da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968
/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*           Copyright (c) 1992-2007 AT&T Knowledge Ventures            *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                      by AT&T Knowledge Ventures                      *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * David Korn
 * AT&T Bell Laboratories
 *
 * dirname path [suffix]
 *
 * print the dirname of a pathname
 */

static const char usage[] =
"[-?\n@(#)$Id: dirname (AT&T Research) 2000-03-07 $\n]"
USAGE_LICENSE
"[+NAME?dirname - return directory portion of file name]"
"[+DESCRIPTION?\bdirname\b treats \astring\a as a file name and returns "
    "the name of the directory containing the file name by deleting "
    "the last component from \astring\a.]"
"[+?If \astring\a consists solely of \b/\b characters the output will "
    "be a single \b/\b unless \bPATH_LEADING_SLASHES\b returned by "
    "\bgetconf\b(1) is \b1\b and \astring\a consists of multiple "
    "\b/\b characters in which case \b//\b will be output.  "
    "Otherwise, trailing \b/\b characters are removed, and if "
    "there are no remaining \b/\b characters in \astring\a, "
    "the string \b.\b will be written to standard output.  "
    "Otherwise, all characters following the last \b/\b are removed. "
    "If the remaining string consists solely of \b/\b characters, "
    "the output will be as if the original string had consisted solely "
    "as \b/\b characters as described above.  Otherwise, all "
    "trailing slashes are removed and the output will be this string "
    "unless this string is empty.  If empty the output will be \b.\b.]"
"\n"
"\n string\n"
"\n"
"[+EXIT STATUS?]{"
        "[+0?Successful Completion.]"
        "[+>0?An error occurred.]"
"}"
"[+SEE ALSO?\bbasename\b(1), \bgetconf\b(1), \bdirname\b(3)]"
;

#include <cmd.h>

static void l_dirname(register Sfio_t *outfile, register const char *pathname)
{
    register const char  *last;
    /* go to end of path */
    for(last=pathname; *last; last++);
    /* back over trailing '/' */
    while(last>pathname && *--last=='/');
    /* back over non-slash chars */
    for(;last>pathname && *last!='/';last--);
    if(last==pathname)
    {
        /* all '/' or "" */
        if(*pathname!='/')
            last = pathname = ".";
    }
    else
    {
        /* back over trailing '/' */
        for(;*last=='/' && last > pathname; last--);
    }
    /* preserve // */
    if(last!=pathname && pathname[0]=='/' && pathname[1]=='/')
    {
        while(pathname[2]=='/' && pathname<last)
            pathname++;
        if(last!=pathname && pathname[0]=='/' && pathname[1]=='/' && *astconf("PATH_LEADING_SLASHES",NiL,NiL)!='1')
            pathname++;
    }
    sfwrite(outfile,pathname,last+1-pathname);
    sfputc(outfile,'\n');
}

int
b_dirname(int argc,register char *argv[], void* context)
{
    register int n;

    cmdinit(argc, argv, context, ERROR_CATALOG, 0);
    while (n = optget(argv, usage)) switch (n)
    {
    case ':':
        error(2, "%s", opt_info.arg);
        break;
    case '?':
        error(ERROR_usage(2), "%s", opt_info.arg);
        break;
    }
    argv += opt_info.index;
    argc -= opt_info.index;
    if(error_info.errors || argc != 1)
        error(ERROR_usage(2),"%s", optusage(NiL));
    l_dirname(sfstdout,argv[0]);
    return(0);
}