80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
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/* dirname - return directory part of PATH.
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Copyright (C) 1996-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <libgen.h>
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#include <string.h>
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char *
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dirname (char *path)
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{
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static const char dot[] = ".";
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char *last_slash;
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/* Find last '/'. */
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last_slash = path != NULL ? strrchr (path, '/') : NULL;
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if (last_slash != NULL && last_slash != path && last_slash[1] == '\0')
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{
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/* Determine whether all remaining characters are slashes. */
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char *runp;
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for (runp = last_slash; runp != path; --runp)
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if (runp[-1] != '/')
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break;
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/* The '/' is the last character, we have to look further. */
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if (runp != path)
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last_slash = __memrchr (path, '/', runp - path);
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}
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if (last_slash != NULL)
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{
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/* Determine whether all remaining characters are slashes. */
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char *runp;
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for (runp = last_slash; runp != path; --runp)
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if (runp[-1] != '/')
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break;
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/* Terminate the path. */
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if (runp == path)
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{
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/* The last slash is the first character in the string. We have to
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return "/". As a special case we have to return "//" if there
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are exactly two slashes at the beginning of the string. See
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XBD 4.10 Path Name Resolution for more information. */
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if (last_slash == path + 1)
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++last_slash;
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else
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last_slash = path + 1;
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}
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else
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last_slash = runp;
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last_slash[0] = '\0';
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}
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else
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/* This assignment is ill-designed but the XPG specs require to
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return a string containing "." in any case no directory part is
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found and so a static and constant string is required. */
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path = (char *) dot;
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return path;
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}
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