129 lines
3.7 KiB
C
129 lines
3.7 KiB
C
/* basename.c -- return the last element in a file name
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Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free
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Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <config.h>
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#include "dirname.h"
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#include <string.h>
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#include "xalloc.h"
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#include "xstrndup.h"
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/* Return the address of the last file name component of NAME. If
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NAME has no relative file name components because it is a file
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system root, return the empty string. */
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char *
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last_component (char const *name)
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{
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char const *base = name + FILE_SYSTEM_PREFIX_LEN (name);
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char const *p;
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bool saw_slash = false;
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while (ISSLASH (*base))
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base++;
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for (p = base; *p; p++)
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{
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if (ISSLASH (*p))
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saw_slash = true;
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else if (saw_slash)
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{
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base = p;
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saw_slash = false;
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}
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}
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return (char *) base;
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}
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/* In general, we can't use the builtin `basename' function if available,
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since it has different meanings in different environments.
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In some environments the builtin `basename' modifies its argument.
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Return the last file name component of NAME, allocated with
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xmalloc. On systems with drive letters, a leading "./"
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distinguishes relative names that would otherwise look like a drive
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letter. Unlike POSIX basename(), NAME cannot be NULL,
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base_name("") returns "", and the first trailing slash is not
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stripped.
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If lstat (NAME) would succeed, then { chdir (dir_name (NAME));
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lstat (base_name (NAME)); } will access the same file. Likewise,
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if the sequence { chdir (dir_name (NAME));
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rename (base_name (NAME), "foo"); } succeeds, you have renamed NAME
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to "foo" in the same directory NAME was in. */
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char *
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base_name (char const *name)
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{
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char const *base = last_component (name);
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size_t length;
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/* If there is no last component, then name is a file system root or the
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empty string. */
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if (! *base)
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return xstrndup (name, base_len (name));
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/* Collapse a sequence of trailing slashes into one. */
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length = base_len (base);
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if (ISSLASH (base[length]))
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length++;
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/* On systems with drive letters, `a/b:c' must return `./b:c' rather
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than `b:c' to avoid confusion with a drive letter. On systems
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with pure POSIX semantics, this is not an issue. */
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if (FILE_SYSTEM_PREFIX_LEN (base))
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{
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char *p = xmalloc (length + 3);
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p[0] = '.';
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p[1] = '/';
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memcpy (p + 2, base, length);
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p[length + 2] = '\0';
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return p;
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}
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/* Finally, copy the basename. */
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return xstrndup (base, length);
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}
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/* Return the length of the basename NAME. Typically NAME is the
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value returned by base_name or last_component. Act like strlen
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(NAME), except omit all trailing slashes. */
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size_t
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base_len (char const *name)
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{
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size_t len;
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size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
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for (len = strlen (name); 1 < len && ISSLASH (name[len - 1]); len--)
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continue;
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if (DOUBLE_SLASH_IS_DISTINCT_ROOT && len == 1
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&& ISSLASH (name[0]) && ISSLASH (name[1]) && ! name[2])
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return 2;
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if (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE && prefix_len
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&& len == prefix_len && ISSLASH (name[prefix_len]))
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return prefix_len + 1;
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return len;
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}
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