summaryrefslogtreecommitdiff
path: root/src/compat/compat-dirname.c
blob: c1523d99378027533b1d39f98dec7b2d2a15ef1b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2011 - David Sommerseth <davids@redhat.com>
 *
 *  This program is free software; you can redistribute it 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 ANY 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.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif


#ifndef HAVE_DIRNAME

#include "compat.h"
#include <string.h>

/* Unoptimised version of glibc memrchr().
 * This is considered fast enough, as only this compat
 * version of dirname() depends on it.
 */
static const char *
__memrchr(const char *str, int c, size_t n)
{
    const char *end = str;

    end += n - 1; /* Go to the end of the string */
    while (end >= str)
    {
        if (c == *end)
        {
            return end;
        }
        else
        {
            end--;
        }
    }
    return NULL;
}

/* Modified version based on glibc-2.14.1 by Ulrich Drepper <drepper@akkadia.org>
 * This version is extended to handle both / and \ in path names.
 */
char *
dirname(char *path)
{
    static const char dot[] = ".";
    char *last_slash;
    char separator = '/';

    /* Find last '/'.  */
    last_slash = path != NULL ? strrchr(path, '/') : NULL;
    /* If NULL, check for \ instead ... might be Windows a path */
    if (!last_slash)
    {
        last_slash = path != NULL ? strrchr(path, '\\') : NULL;
        separator = last_slash ? '\\' : '/'; /* Change the separator if \ was found */
    }

    if (last_slash != NULL && last_slash != path && last_slash[1] == '\0')
    {
        /* Determine whether all remaining characters are slashes.  */
        char *runp;

        for (runp = last_slash; runp != path; --runp)
        {
            if (runp[-1] != separator)
            {
                break;
            }
        }

        /* The '/' is the last character, we have to look further.  */
        if (runp != path)
        {
            last_slash = (char *) __memrchr(path, separator, runp - path);
        }
    }

    if (last_slash != NULL)
    {
        /* Determine whether all remaining characters are slashes.  */
        char *runp;

        for (runp = last_slash; runp != path; --runp)
        {
            if (runp[-1] != separator)
            {
                break;
            }
        }

        /* Terminate the path.  */
        if (runp == path)
        {
            /* The last slash is the first character in the string.  We have to
             * return "/".  As a special case we have to return "//" if there
             * are exactly two slashes at the beginning of the string.  See
             * XBD 4.10 Path Name Resolution for more information.  */
            if (last_slash == path + 1)
            {
                ++last_slash;
            }
            else
            {
                last_slash = path + 1;
            }
        }
        else
        {
            last_slash = runp;
        }

        last_slash[0] = '\0';
    }
    else
    {
        /* This assignment is ill-designed but the XPG specs require to
         * return a string containing "." in any case no directory part is
         * found and so a static and constant string is required.  */
        path = (char *) dot;
    }

    return path;
}

#endif /* HAVE_DIRNAME */