/* path-concat.c -- concatenate two arbitrary pathnames
- Copyright (C) 1996 Free Software Foundation, Inc.
+
+ Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 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
/* Written by Jim Meyering. */
-#ifdef HAVE_CONFIG_H
-#include <config.h>
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "path-concat.h"
+
+#include <string.h>
+
+#include "dirname.h"
+#include "xalloc.h"
+
+#if ! HAVE_MEMPCPY && ! defined mempcpy
+# define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
#endif
-char *malloc ();
-char *stpcpy ();
+/* Return the longest suffix of F that is a relative file name.
+ If it has no such suffix, return the empty string. */
-/* Concatenate two pathname components, DIR and BASE, in newly-allocated
- storage and return the result. Return 0 if out of memory. Add a slash
- between DIR and BASE in the result if neither would contribute one.
- If each would contribute at least one, elide one from the end of DIR.
- Otherwise, simply concatenate DIR and BASE. In any case, if
- BASE_IN_RESULT is non-NULL, set *BASE_IN_RESULT to point to the copy of
- BASE in the returned concatenation. */
+static char const *
+longest_relative_suffix (char const *f)
+{
+ for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++)
+ continue;
+ return f;
+}
+
+/* Concatenate two pathname components, DIR and ABASE, in
+ newly-allocated storage and return the result.
+ The resulting file name F is such that the commands "ls F" and "(cd
+ DIR; ls BASE)" refer to the same file, where BASE is ABASE with any
+ file system prefixes and leading separators removed.
+ Arrange for a directory separator if necessary between DIR and BASE
+ in the result, removing any redundant separators.
+ In any case, if BASE_IN_RESULT is non-NULL, set
+ *BASE_IN_RESULT to point to the copy of BASE in the returned
+ concatenation.
+
+ Report an error if memory is exhausted. */
char *
-path_concat (const char *dir, const char *base, char **base_in_result)
+path_concat (char const *dir, char const *abase, char **base_in_result)
{
- char *p;
- char *p_concat;
+ char const *dirbase = base_name (dir);
+ size_t dirbaselen = base_len (dirbase);
+ size_t dirlen = dirbase - dir + dirbaselen;
+ size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1]));
- p_concat = malloc (strlen (dir) + strlen (base) + 2);
- if (!p_concat)
- return 0;
+ char const *base = longest_relative_suffix (abase);
+ size_t baselen = strlen (base);
- p = stpcpy (p_concat, dir);
+ char *p_concat = xmalloc (dirlen + needs_separator + baselen + 1);
+ char *p;
- if (*(p - 1) == '/' && *base == '/')
- --p;
- else if (*(p - 1) != '/' && *base != '/')
- p = stpcpy (p, "/");
+ p = mempcpy (p_concat, dir, dirlen);
+ *p = DIRECTORY_SEPARATOR;
+ p += needs_separator;
if (base_in_result)
*base_in_result = p;
- stpcpy (p, base);
+ p = mempcpy (p, base, baselen);
+ *p = '\0';
return p_concat;
}