path.c

一款类linux的操作系统源码

/* 
 *  Roadrunner/pk
 *    Copyright (C) 1989-2001  Cornfed Systems, Inc.
 *
 *  The Roadrunner/pk operating system is free software; you can
 *  redistribute and/or modify it under the terms of the GNU General
 *  Public License, version 2, as published by the Free Software
 *  Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307 USA
 *
 *  More information about the Roadrunner/pk operating system of
 *  which this file is a part is available on the World-Wide Web
 *  at: http://www.cornfed.com.
 *
 */

#include <fs.h>
#if _DEBUG
#include <stdio.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <sys/mem.h>

void
getdir(char *path, char *dir)
{
    int len, i;

    if (strlen(path) == 0) {
#if _DEBUG
	kprintf("getdir: zero length path\n");
#endif
	strcpy(dir, "");
	return;
    }
    if (strcmp(path, "/") == 0) {
#if _DEBUG
	kprintf("getdir: root directory\n");
#endif
	strcpy(dir, "/");
	return;
    }
    i = strlen(path);
    while (path[i - 1] == '/')
	i--;

    while (i > 0 && path[--i] != '/');
    strncpy(dir, path, i + 1);
    dir[i + 1] = '\0';

    if (strcmp(dir, "/") != 0 && dir[(len = strlen(dir)) - 1] == '/')
	dir[len - 1] = '\0';
}

void
getname(char *path, char *name)
{
    int i, len;

    if (strlen(path) == 0 || strcmp(path, "/") == 0) {
	strcpy(name, "");
	return;
    }
    len = strlen(path);
    while (path[len - 1] == '/')
	len--;
    i = len - 1;

    for (i = len - 1; i >= 0; i--)
	if (path[i] == '/')
	    break;
    strncpy(name, path + i + 1, len - i - 1);
    name[len - i - 1] = '\0';
}

#define ELEM_LENGTH	132

void
mkpath(char *dir, char *name, char *path)
{
    char elem[ELEM_LENGTH];
    int pos, start, len;

    if (dir == NULL || name == NULL || path == NULL)
	return;

    for (strcpy(path, dir), pos = 0; name[pos] != '\0';) {
	while (name[pos] == '/')
	    pos++;

	for (start = pos; name[pos] != '/' && name[pos] != '\0'; pos++)
	    len = pos - start + 1;
	strncpy(elem, name + start,
		(len < ELEM_LENGTH - 1 ? len : ELEM_LENGTH - 1));
	elem[(len < ELEM_LENGTH - 1 ? len : ELEM_LENGTH - 1)] = '\0';

	if (strcmp(elem, "..") == 0) {
	    char *s;

	    if ((s = (char *) malloc(PATH_LENGTH)) == NULL)
		return;

	    strcpy(s, path);
	    getdir(s, path);
	    free(s);

	} else if (strcmp(elem, ".") != 0) {
	    len = strlen(path);
	    if (len == 0)
		strcpy(path, elem);
	    else if (path[len - 1] == '/') {
		if (elem[0] == '/')
		    strcat(path, elem + 1);
		else
		    strcat(path, elem);
	    } else {
		if (elem[0] == '/')
		    strcat(path, elem);
		else {
		    strcat(path, "/");
		    strcat(path, elem);
		}
	    }
	}
    }
    if (strcmp(path, "/") != 0 && path[(len = strlen(path)) - 1] == '/')
	path[len - 1] = '\0';
}