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/* Construct a full filename from a directory and a relative filename. 
   Copyright (C) 2001-2004, 2006-2013 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 3 of the License, or 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, see <http://www.gnu.org/licenses/>.  */ 
 
/* Written by Bruno Haible <haible@clisp.cons.org>.  */ 
 
#include <config.h> 
 
/* Specification.  */ 
#include "concat-filename.h" 
 
#include <errno.h> 
#include <stdlib.h> 
#include "string--.h"
 
#include "filename.h" 
 
/* Concatenate a directory filename, a relative filename and an optional 
   suffix.  The directory may end with the directory separator.  The second 
   argument may not start with the directory separator (it is relative). 
   Return a freshly allocated filename.  Return NULL and set errno 
   upon memory allocation failure.  */ 
char * 
concatenated_filename (const char *directory, const char *filename, 
                       const char *suffix) 
{ 
  char *result; 
  char *p; 
 
  if (strcmp (directory, ".") == 0) 
    { 
      /* No need to prepend the directory.  */ 
      result = (char *) malloc (strlen (filename) 
                                + (suffix != NULL ? strlen (suffix) : 0) 
                                + 1); 
      if (result == NULL) 
        return NULL; /* errno is set here */ 
      p = result; 
    } 
  else 
    { 
      size_t directory_len = strlen (directory); 
      int need_slash = 
        (directory_len > FILE_SYSTEM_PREFIX_LEN (directory) 
         && !ISSLASH (directory[directory_len - 1])); 
      result = (char *) malloc (directory_len + need_slash 
                                + strlen (filename) 
                                + (suffix != NULL ? strlen (suffix) : 0) 
                                + 1); 
      if (result == NULL) 
        return NULL; /* errno is set here */ 
      memcpy (result, directory, directory_len); 
      p = result + directory_len; 
      if (need_slash) 
        *p++ = '/'; 
    } 
  p = stpcpy (p, filename); 
  if (suffix != NULL) 
    stpcpy (p, suffix); 
  return result; 
}