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Diffstat (limited to 'lib/basename.c')
-rw-r--r-- | lib/basename.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/lib/basename.c b/lib/basename.c new file mode 100644 index 0000000..fbe17ff --- /dev/null +++ b/lib/basename.c @@ -0,0 +1,129 @@ +/* basename.c -- return the last element in a file name + + Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free + Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + 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. */ + +#include <config.h> + +#include "dirname.h" + +#include <string.h> +#include "xalloc.h" +#include "xstrndup.h" + +/* Return the address of the last file name component of NAME. If + NAME has no relative file name components because it is a file + system root, return the empty string. */ + +char * +last_component (char const *name) +{ + char const *base = name + FILE_SYSTEM_PREFIX_LEN (name); + char const *p; + bool saw_slash = false; + + while (ISSLASH (*base)) + base++; + + for (p = base; *p; p++) + { + if (ISSLASH (*p)) + saw_slash = true; + else if (saw_slash) + { + base = p; + saw_slash = false; + } + } + + return (char *) base; +} + + +/* In general, we can't use the builtin `basename' function if available, + since it has different meanings in different environments. + In some environments the builtin `basename' modifies its argument. + + Return the last file name component of NAME, allocated with + xmalloc. On systems with drive letters, a leading "./" + distinguishes relative names that would otherwise look like a drive + letter. Unlike POSIX basename(), NAME cannot be NULL, + base_name("") returns "", and the first trailing slash is not + stripped. + + If lstat (NAME) would succeed, then { chdir (dir_name (NAME)); + lstat (base_name (NAME)); } will access the same file. Likewise, + if the sequence { chdir (dir_name (NAME)); + rename (base_name (NAME), "foo"); } succeeds, you have renamed NAME + to "foo" in the same directory NAME was in. */ + +char * +base_name (char const *name) +{ + char const *base = last_component (name); + size_t length; + + /* If there is no last component, then name is a file system root or the + empty string. */ + if (! *base) + return xstrndup (name, base_len (name)); + + /* Collapse a sequence of trailing slashes into one. */ + length = base_len (base); + if (ISSLASH (base[length])) + length++; + + /* On systems with drive letters, `a/b:c' must return `./b:c' rather + than `b:c' to avoid confusion with a drive letter. On systems + with pure POSIX semantics, this is not an issue. */ + if (FILE_SYSTEM_PREFIX_LEN (base)) + { + char *p = xmalloc (length + 3); + p[0] = '.'; + p[1] = '/'; + memcpy (p + 2, base, length); + p[length + 2] = '\0'; + return p; + } + + /* Finally, copy the basename. */ + return xstrndup (base, length); +} + +/* Return the length of the basename NAME. Typically NAME is the + value returned by base_name or last_component. Act like strlen + (NAME), except omit all trailing slashes. */ + +size_t +base_len (char const *name) +{ + size_t len; + size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name); + + for (len = strlen (name); 1 < len && ISSLASH (name[len - 1]); len--) + continue; + + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && len == 1 + && ISSLASH (name[0]) && ISSLASH (name[1]) && ! name[2]) + return 2; + + if (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE && prefix_len + && len == prefix_len && ISSLASH (name[prefix_len])) + return prefix_len + 1; + + return len; +} |