/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*           Copyright (c) 1985-2007 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>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * Glenn Fowler
 * AT&T Bell Laboratories
 *
 * in place replace of first occurrence of /match/ with /replace/ in path
 * end of path returned
 */

#include <ast.h>

char*
pathrepl(register char* path, const char* match, register const char* replace)
{
	register const char*	m = match;
	register const char*	r;
	char*			t;

	if (!match) match = "";
	if (!replace) replace = "";
	if (streq(match, replace))
		return(path + strlen(path));
	for (;;)
	{
		while (*path && *path++ != '/');
		if (!*path) break;
		if (*path == *m)
		{
			t = path;
			while (*m && *m++ == *path) path++;
			if (!*m && *path == '/')
			{
				register char*	p;

				p = t;
				r = replace;
				while (p < path && *r) *p++ = *r++;
				if (p < path) while (*p++ = *path++);
				else if (*r && p >= path)
				{
					register char*	u;

					t = path + strlen(path);
					u = t + strlen(r);
					while (t >= path) *u-- = *t--;
					while (*r) *p++ = *r++;
				}
				else p += strlen(p) + 1;
				return(p - 1);
			}
			path = t;
			m = match;
		}
	}
	return(path);
}