path.c

   1 /* -*- Mode: C ; c-basic-offset: 2 -*- */
   2 /*****************************************************************************
   3  *
   4  *   Filesystem path helpers
   5  *   This file is part of monster
   6  *
   7  *   Copyright (C) 2006,2007 Nedko Arnaudov <nedko@arnaudov.name>
   8  *
   9  *   This program is free software; you can redistribute it and/or modify
  10  *   it under the terms of the GNU General Public License as published by
  11  *   the Free Software Foundation; version 2 of the License
  12  *
  13  *   This program is distributed in the hope that it will be useful,
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *   GNU General Public License for more details.
  17  *
  18  *   You should have received a copy of the GNU General Public License
  19  *   along with this program; if not, write to the Free Software
  20  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  *****************************************************************************/
  23
  24 #include <string.h>
  25 #include <assert.h>
  26
  27 #define DISABLE_DEBUG_OUTPUT
  28
  29 #include "log.h"
  30 #include "path.h"
  31
  32 void
  33 path_normalize(char * path_ptr)
  34 {
  35   char * temp_ptr;
  36   unsigned int dirs_available;
  37   size_t left;
  38   char * previous_dir_ptr;
  39
  40   DEBUG_OUT("Normalizing filesystem path \"%s\"", path_ptr);
  41
  42   temp_ptr = path_ptr;
  43   dirs_available = 0;
  44   left = strlen(temp_ptr)+1;
  45
  46 loop:
  47   //DEBUG_OUT("%u chars left to process", left);
  48
  49   if (*temp_ptr == 0)
  50     goto done;
  51
  52   if ((temp_ptr == path_ptr || temp_ptr[-1] == '/') &&
  53       temp_ptr[0] == '.' &&
  54       temp_ptr[1] == '/')
  55   {
  56     DEBUG_OUT("");
  57     DEBUG_OUT("Skipping '.' from      \"%s\"", temp_ptr);
  58     memmove(temp_ptr, temp_ptr + 2, left);
  59     DEBUG_OUT("Skipping '.' result is \"%s\"", temp_ptr);
  60     DEBUG_OUT("Skipping '.' global result is \"%s\"", path_ptr);
  61     left -= 2;
  62     goto loop;
  63   }
  64
  65   if (temp_ptr[0] == '.' &&
  66       temp_ptr[1] == '.' &&
  67       temp_ptr[2] == '/' &&
  68       dirs_available > 0)
  69   {
  70     DEBUG_OUT("");
  71     DEBUG_OUT("Skipping '..' from      \"%s\"", temp_ptr);
  72
  73     assert(temp_ptr > path_ptr + 2);
  74
  75     previous_dir_ptr = temp_ptr - 2;
  76     while (previous_dir_ptr > path_ptr &&
  77            *previous_dir_ptr != '/')
  78     {
  79       previous_dir_ptr--;
  80     }
  81
  82     if (*previous_dir_ptr == '/')
  83     {
  84       previous_dir_ptr++;
  85     }
  86
  87     DEBUG_OUT("Previous dir \"%s\"", previous_dir_ptr);
  88
  89     left -= 3;
  90     memmove(previous_dir_ptr, temp_ptr + 3, left);
  91     temp_ptr = previous_dir_ptr;
  92
  93     dirs_available--;
  94
  95     DEBUG_OUT("Skipping '..' result is \"%s\"", temp_ptr);
  96     DEBUG_OUT("Skipping '..' global result is \"%s\"", path_ptr);
  97
  98     goto loop;
  99   }
 100
 101   if (temp_ptr > path_ptr &&
 102       *temp_ptr == '/')
 103   {
 104     dirs_available++;
 105   }
 106
 107   temp_ptr++;
 108   left--;
 109   goto loop;
 110
 111 done:
 112   DEBUG_OUT("Filesystem path normalized to \"%s\"", path_ptr);
 113   assert(left == 1);          /* the terminating zero */
 114 }