/* 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; }