/*
 * which: locate a file in your PATH
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "glob.h"

char *extension[] = { ".com", ".exe", ".bat" };

#define NUM_EXTENSIONS	(sizeof extension / sizeof extension[0])

main(argc, argv)
char **argv;
{
    char *path = getenv("PATH");
    register st, i;

    if (argc < 2) {
	fprintf(stderr, "usage: which file [...]\n");
	exit(1);
    }

    for (st=i=1; i<argc; i++)
	if ((st=findfile(argv[i], ".")) != 0 && path)
	    st=findfile(argv[i], path);
    exit(st);
} /* which */


/*
 * mapslash() converts backslashes to forward slashes
 */
mapslash(p)
register char *p;
{
    strlwr(p);
    for (; *p; p++)
	if (*p == '\\')
	    *p = '/';
} /* mapslash */


/*
 * findfile() looks for a file in a given pathlist
 */
findfile(name,path)
char *name, *path;
{
    char *p, *q, *dot, *gdot, *pathname;
    char bfr[256];
    register j;
    char *sep;

    for (p=path; p; p=q) {
	q = strchr(p, ';');
	if (q) {
	    sep = (q[-1] == ':') ? "" : "/";
	    sprintf(bfr, "%.*s%s%s", (int)(q-p), p, sep, name);
	    ++q;
	}
	else {
	    sep = (p[strlen(p)-1] == ':') ? "" : "/";
	    sprintf(bfr, "%s%s%s", p, sep, name);
	}

	if ((dot=strrchr(name, '.')) == (char*)0)
	    /* no extension supplied - look for one */
	    strcat(bfr, ".*");

	if (pathname=glob(bfr, (struct glob_t*)0)) {
	    /* found a match
	     */
	    if (!dot)
		/* now we need to see if it's the proper match
		 */
		do {
		    if (gdot = strrchr(pathname, '.'))
			for (j=0; j<NUM_EXTENSIONS; j++)
			    if (strcmp(gdot, extension[j]) == 0)
				goto found;
		} while (pathname=glob((char*)0, (struct glob_t*)0));

	    if (pathname) {
	found:  mapslash(pathname);
		puts(pathname);
		return 0;
	    }
	} /* if (pathname=glob(...)) */
    }
    return 1;
} /* findfile */