packfile.h

   1 /*
   2     Copyright (C) 2005-2007 Tom Beaumont
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17 */
  18
  19 #include <stdint.h>
  20 #include <SDL/SDL_endian.h>
  21
  22 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
  23 #define SWAP16(X)    (X)
  24 #define SWAP32(X)    (X)
  25 #else
  26 #define SWAP16(X)    SDL_Swap16(X)
  27 #define SWAP32(X)    SDL_Swap32(X)
  28 #endif
  29
  30 struct PackFile1
  31 {
  32         class Entry {
  33                 int32_t len;
  34         public:
  35                 char name[1];
  36
  37                 Entry* GetNext()
  38                 {
  39                         return (Entry*)((char*)name + len);
  40                 }
  41
  42                 void* Data()
  43                 {
  44                         char* pos = name;
  45                         while (*pos!=0)
  46                                 pos++;
  47                         return pos+1;
  48                 }
  49
  50                 int DataLen()
  51                 {
  52                         return len - strlen(name) - 1;
  53                 }
  54         };
  55
  56         int numfiles;
  57         Entry** e;
  58         void* data;
  59
  60         PackFile1() : e(0), data(0), numfiles(0)
  61         {}
  62
  63         Entry* Find(const char* name)
  64         {
  65                 if (numfiles==0) return 0;
  66                 int a=0, b=numfiles;
  67                 while (b>a)
  68                 {
  69                         const int mid = (a+b)>>1;
  70                         int diff = strcmp(name, e[mid]->name);
  71                         if (diff==0)
  72                                 return e[mid];
  73                         else if (diff < 0)
  74                                 b=mid;
  75                         else
  76                                 a=mid+1;
  77                 }
  78                 return 0;
  79         }
  80
  81         void Read(FILE* f)
  82         {
  83                 if (numfiles || e || data)
  84                         FATAL("Calling Packfile1::Read when already initialised.");
  85
  86                 int32_t size;
  87                 fseek(f, -(int)sizeof(size), SEEK_END);
  88                 int end_offset = ftell(f);
  89                 fread(&size, sizeof(size), 1, f);
  90                 size = SWAP32(size);
  91                 fseek(f, end_offset - size, SEEK_SET);
  92
  93                 data = malloc(size);
  94                 char* data_end = (char*)data + size;
  95                 fread(data, 1, size, f);
  96
  97                 numfiles=0;
  98                 Entry* i = (Entry*)data;
  99                 while ((void*)i < data_end)
 100                 {
 101                         numfiles++;
 102                         int32_t *data_length = (int32_t*)i;
 103                         *data_length = SWAP32(*data_length);
 104                         i = i->GetNext();
 105                 }
 106
 107                 e = new Entry* [numfiles]; // CHECKME: where to delete?
 108
 109                 i = (Entry*)data;
 110                 for (int j=0; j<numfiles; j++, i = i->GetNext())
 111                         e[j] = i;
 112         }
 113
 114         ~PackFile1()
 115         {
 116                 free(data);
 117         }
 118
 119 };