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
  20 struct PackFile1
  21 {
  22         class Entry {
  23                 int len;
  24         public:
  25                 char name[1];
  26
  27                 Entry* GetNext()
  28                 {
  29                         return (Entry*)((char*)name + len);
  30                 }
  31
  32                 void* Data()
  33                 {
  34                         char* pos = name;
  35                         while (*pos!=0)
  36                                 pos++;
  37                         return pos+1;
  38                 }
  39
  40                 int DataLen()
  41                 {
  42                         return len - strlen(name) - 1;
  43                 }
  44         };
  45
  46         int numfiles;
  47         Entry** e;
  48         void* data;
  49
  50         PackFile1() : e(0), data(0), numfiles(0)
  51         {}
  52
  53         Entry* Find(const char* name)
  54         {
  55                 if (numfiles==0) return 0;
  56                 int a=0, b=numfiles;
  57                 while (b>a)
  58                 {
  59                         const int mid = (a+b)>>1;
  60                         int diff = strcmp(name, e[mid]->name);
  61                         if (diff==0)
  62                                 return e[mid];
  63                         else if (diff < 0)
  64                                 b=mid;
  65                         else
  66                                 a=mid+1;
  67                 }
  68                 return 0;
  69         }
  70
  71         void Read(FILE* f)
  72         {
  73                 if (numfiles || e || data)
  74                         FATAL("Calling Packfile1::Read when already initialised.");
  75
  76                 int size;
  77                 fseek(f, -(int)sizeof(size), SEEK_END);
  78                 int end_offset = ftell(f);
  79                 fread(&size, sizeof(size), 1, f);
  80                 fseek(f, end_offset - size, SEEK_SET);
  81
  82                 data = malloc(size);
  83                 char* data_end = (char*)data + size;
  84                 fread(data, 1, size, f);
  85
  86                 numfiles=0;
  87                 Entry* i = (Entry*)data;
  88                 while ((void*)i < data_end)
  89                 {
  90                         numfiles++;
  91                         i = i->GetNext();
  92                 }
  93
  94                 e = new Entry* [numfiles];
  95
  96                 i = (Entry*)data;
  97                 for (int j=0; j<numfiles; j++, i = i->GetNext())
  98                         e[j] = i;
  99         }
 100
 101         ~PackFile1()
 102         {
 103                 free(data);
 104         }
 105
 106 };