Line data    Source code

       1             : /* Concatenate two arbitrary file names.
       2             : 
       3             :    Copyright (C) 1996-2007 Free Software Foundation, Inc.
       4             : 
       5             :    This program is free software: you can redistribute it and/or modify
       6             :    it under the terms of the GNU General Public License as published by
       7             :    the Free Software Foundation; either version 3 of the License, or
       8             :    (at your option) any later version.
       9             : 
      10             :    This program is distributed in the hope that it will be useful,
      11             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13             :    GNU General Public License for more details.
      14             : 
      15             :    You should have received a copy of the GNU General Public License
      16             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      17             : 
      18             : /* Written by Jim Meyering.  */
      19             : 
      20             : #include <config.h>
      21             : 
      22             : /* Specification.  */
      23             : #include "filenamecat.h"
      24             : 
      25             : #include <stdlib.h>
      26             : #include <string.h>
      27             : 
      28             : #include "dirname.h"
      29             : #include "xalloc.h"
      30             : 
      31             : #if ! HAVE_MEMPCPY && ! defined mempcpy
      32             : # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
      33             : #endif
      34             : 
      35             : /* Return the longest suffix of F that is a relative file name.
      36             :    If it has no such suffix, return the empty string.  */
      37             : 
      38             : static char const *
      39        2162 : longest_relative_suffix (char const *f)
      40             : {
      41        2162 :   for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++)
      42           0 :     continue;
      43        2162 :   return f;
      44             : }
      45             : 
      46             : /* Concatenate two file name components, DIR and ABASE, in
      47             :    newly-allocated storage and return the result.
      48             :    The resulting file name F is such that the commands "ls F" and "(cd
      49             :    DIR; ls BASE)" refer to the same file, where BASE is ABASE with any
      50             :    file system prefixes and leading separators removed.
      51             :    Arrange for a directory separator if necessary between DIR and BASE
      52             :    in the result, removing any redundant separators.
      53             :    In any case, if BASE_IN_RESULT is non-NULL, set
      54             :    *BASE_IN_RESULT to point to the copy of ABASE in the returned
      55             :    concatenation.  However, if ABASE begins with more than one slash,
      56             :    set *BASE_IN_RESULT to point to the sole corresponding slash that
      57             :    is copied into the result buffer.
      58             : 
      59             :    Return NULL if malloc fails.  */
      60             : 
      61             : char *
      62        2162 : mfile_name_concat (char const *dir, char const *abase, char **base_in_result)
      63             : {
      64        2162 :   char const *dirbase = last_component (dir);
      65        2162 :   size_t dirbaselen = base_len (dirbase);
      66        2162 :   size_t dirlen = dirbase - dir + dirbaselen;
      67        2162 :   size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1]));
      68             : 
      69        2162 :   char const *base = longest_relative_suffix (abase);
      70        2162 :   size_t baselen = strlen (base);
      71             : 
      72        2162 :   char *p_concat = malloc (dirlen + needs_separator + baselen + 1);
      73             :   char *p;
      74             : 
      75        2162 :   if (p_concat == NULL)
      76           0 :     return NULL;
      77             : 
      78        2162 :   p = mempcpy (p_concat, dir, dirlen);
      79        2162 :   *p = DIRECTORY_SEPARATOR;
      80        2162 :   p += needs_separator;
      81             : 
      82        2162 :   if (base_in_result)
      83          48 :     *base_in_result = p - IS_ABSOLUTE_FILE_NAME (abase);
      84             : 
      85        2162 :   p = mempcpy (p, base, baselen);
      86        2162 :   *p = '\0';
      87             : 
      88        2162 :   return p_concat;
      89             : }
      90             : 
      91             : /* Just like mfile_name_concat, above, except, rather than
      92             :    returning NULL upon malloc failure, here, we report the
      93             :    "memory exhausted" condition and exit.  */
      94             : 
      95             : char *
      96        2162 : file_name_concat (char const *dir, char const *abase, char **base_in_result)
      97             : {
      98        2162 :   char *p = mfile_name_concat (dir, abase, base_in_result);
      99        2162 :   if (p == NULL)
     100           0 :     xalloc_die ();
     101        2162 :   return p;
     102             : }