diff options
author | Jim Meyering <jim@meyering.net> | 2006-03-26 12:20:46 +0000 |
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committer | Jim Meyering <jim@meyering.net> | 2006-03-26 12:20:46 +0000 |
commit | 8773d59d5580364ecc2055acab39b6b98469b289 (patch) | |
tree | 66e973feae99757b986e39930ade5b6dc6a91eee | |
parent | 8132c6e76ee97bc1af375ff1701729e0ac5218b9 (diff) | |
download | coreutils-8773d59d5580364ecc2055acab39b6b98469b289.tar.xz |
(base_name): New semantics - malloc the result.
Preserve // when it is special.
Preserve relative files that look like drive letters.
(base_len): Preserve // when it is special.
(last_component): New method, similar to old base_name semantics.
-rw-r--r-- | lib/basename.c | 104 |
1 files changed, 78 insertions, 26 deletions
diff --git a/lib/basename.c b/lib/basename.c index 5cc97cd4a..8c3dbece7 100644 --- a/lib/basename.c +++ b/lib/basename.c @@ -1,6 +1,6 @@ /* basename.c -- return the last element in a file name - Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005 Free + 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 @@ -22,58 +22,110 @@ #endif #include "dirname.h" -#include <string.h> -/* 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. +#include <string.h> +#include "xalloc.h" +#include "xstrndup.h" - Return the address of the last file name component of NAME. If - NAME has no file name components because it is all slashes, return - NAME if it is empty, the address of its last slash otherwise. */ +/* 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 * -base_name (char const *name) +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) { - /* Treat multiple adjacent slashes like a single slash. */ - do p++; - while (ISSLASH (*p)); - - /* If the file name ends in slash, use the trailing slash as - the basename if no non-slashes have been found. */ - if (! *p) - { - if (ISSLASH (*base)) - base = p - 1; - break; - } - - /* *P is a non-slash preceded by a slash. */ base = p; + saw_slash = false; } } return (char *) base; } -/* Return the length of of the basename NAME. Typically NAME is the - value returned by base_name. Act like strlen (NAME), except omit - redundant trailing slashes. */ + +/* 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; } |