RoomFile.c

   1 #include "RoomFile.h"
   2 #include <stdlib.h>
   3
   4 ssize_t ARF_find_code_start(AF* f, size_t start) {
   5         if(!AF_set_pos(f, start)) return -1;
   6         char buf[4];
   7         unsigned match = 0;
   8         while(1) {
   9                 if(AF_read(f, buf, 1) != 1) break;;
  10                 switch(match) {
  11                         case 0:
  12                                 if(*buf == 'S') match++;
  13                                 else match = 0;
  14                                 break;
  15                         case 1:
  16                                 if(*buf == 'C') match++;
  17                                 else match = 0;
  18                                 break;
  19                         case 2:
  20                                 if(*buf == 'O') match++;
  21                                 else match = 0;
  22                                 break;
  23                         case 3:
  24                                 if(*buf == 'M') return AF_get_pos(f) - 4;
  25                                 else match = 0;
  26                                 break;
  27                         default:
  28                                 assert(0);
  29                 }
  30         }
  31         return -1;
  32 }
  33
  34 enum BlockType {
  35         BLOCKTYPE_MAIN = 1,
  36         BLOCKTYPE_SCRIPT = 2,
  37         BLOCKTYPE_COMPSCRIPT = 3,
  38         BLOCKTYPE_COMPSCRIPT2 = 4,
  39         BLOCKTYPE_OBJECTNAMES = 5,
  40         BLOCKTYPE_ANIMBKGRND = 6,
  41         BLOCKTYPE_COMPSCRIPT3 = 7, /* only bytecode script type supported by released engine code */
  42         BLOCKTYPE_PROPERTIES = 8,
  43         BLOCKTYPE_OBJECTSCRIPTNAMES = 9,
  44         BLOCKTYPE_EOF = 0xFF
  45 };
  46
  47 static void roomfile_decrypt_text(char *s, int len) {
  48         unsigned i = 0;
  49         while (i < len) {
  50                 *s += "Avis Durgan"[i % 11];
  51                 if (!*s) break;
  52                 ++i; ++s;
  53         }
  54 }
  55
  56
  57 int RoomFile_read(AF *f, struct RoomFile *r, int flags) {
  58         if(!AF_set_pos(f, 0)) return 0;
  59         r->version = AF_read_short(f);
  60         while(1) {
  61                 unsigned char blocktype;
  62                 if((size_t) -1 == AF_read(f, &blocktype, 1)) return 0;
  63                 if(blocktype == BLOCKTYPE_EOF) break;
  64                 int blocklen = AF_read_int(f);
  65                 off_t curr_pos = AF_get_pos(f), next_block = curr_pos + blocklen;
  66                 switch(blocktype) {
  67                         case BLOCKTYPE_SCRIPT:
  68                                 if(flags & RF_FLAGS_EXTRACT_CODE) {
  69                                         int scriptlen = AF_read_int(f);
  70                                         r->sourcecode = malloc(scriptlen+1);
  71                                         if((size_t) -1 == AF_read(f, r->sourcecode, scriptlen)) return 0;
  72                                         roomfile_decrypt_text(r->sourcecode, scriptlen);
  73                                         r->sourcecode[scriptlen] = 0;
  74                                         r->sourcecode_len = scriptlen;
  75                                 }
  76                                 break;
  77                         case BLOCKTYPE_COMPSCRIPT3:
  78                                 {
  79                                         char sig[4];
  80                                         AF_read(f, sig, 4);
  81                                         assert(!memcmp(sig, "SCOM", 4));
  82                                         r->scriptpos = curr_pos;
  83                                 }
  84                                 break;
  85                         /* the older script types weren't supported by the released AGS sources ever */
  86                         default:
  87                                 break;
  88                 }
  89                 if(!AF_set_pos(f, next_block)) return 0;
  90         }
  91         return 1;
  92 }