contrib/games/wolf3d/id_pm.cpp

   1 #include "wl_def.h"
   2
   3 int ChunksInFile;
   4 int PMSpriteStart;
   5 int PMSoundStart;
   6
   7 bool PMSoundInfoPagePadded = false;
   8
   9 // holds the whole VSWAP
  10 uint32_t *PMPageData;
  11 size_t PMPageDataSize;
  12
  13 // ChunksInFile+1 pointers to page starts.
  14 // The last pointer points one byte after the last page.
  15 uint8_t **PMPages;
  16
  17 void PM_Startup()
  18 {
  19     char fname[13] = "vswap.";
  20     strcat(fname,extension);
  21
  22     FILE *file = fopen(fname,"rb");
  23     if(!file)
  24         CA_CannotOpen(fname);
  25
  26     ChunksInFile = 0;
  27     fread(&ChunksInFile, sizeof(word), 1, file);
  28     PMSpriteStart = 0;
  29     fread(&PMSpriteStart, sizeof(word), 1, file);
  30     PMSoundStart = 0;
  31     fread(&PMSoundStart, sizeof(word), 1, file);
  32
  33     uint32_t* pageOffsets = (uint32_t *) malloc((ChunksInFile + 1) * sizeof(int32_t));
  34     CHECKMALLOCRESULT(pageOffsets);
  35     fread(pageOffsets, sizeof(uint32_t), ChunksInFile, file);
  36
  37     word *pageLengths = (word *) malloc(ChunksInFile * sizeof(word));
  38     CHECKMALLOCRESULT(pageLengths);
  39     fread(pageLengths, sizeof(word), ChunksInFile, file);
  40
  41     fseek(file, 0, SEEK_END);
  42     long fileSize = ftell(file);
  43     long pageDataSize = fileSize - pageOffsets[0];
  44     if(pageDataSize > (size_t) -1)
  45         Quit("The page file \"%s\" is too large!", fname);
  46
  47     pageOffsets[ChunksInFile] = fileSize;
  48
  49     uint32_t dataStart = pageOffsets[0];
  50     int i;
  51
  52     // Check that all pageOffsets are valid
  53     for(i = 0; i < ChunksInFile; i++)
  54     {
  55         if(!pageOffsets[i]) continue;   // sparse page
  56         if(pageOffsets[i] < dataStart || pageOffsets[i] >= (size_t) fileSize)
  57             Quit("Illegal page offset for page %i: %u (filesize: %u)",
  58                     i, pageOffsets[i], fileSize);
  59     }
  60
  61     // Calculate total amount of padding needed for sprites and sound info page
  62     int alignPadding = 0;
  63     for(i = PMSpriteStart; i < PMSoundStart; i++)
  64     {
  65         if(!pageOffsets[i]) continue;   // sparse page
  66         uint32_t offs = pageOffsets[i] - dataStart + alignPadding;
  67         if(offs & 1)
  68             alignPadding++;
  69     }
  70
  71     if((pageOffsets[ChunksInFile - 1] - dataStart + alignPadding) & 1)
  72         alignPadding++;
  73
  74     PMPageDataSize = (size_t) pageDataSize + alignPadding;
  75     PMPageData = (uint32_t *) malloc(PMPageDataSize);
  76     CHECKMALLOCRESULT(PMPageData);
  77
  78     PMPages = (uint8_t **) malloc((ChunksInFile + 1) * sizeof(uint8_t *));
  79     CHECKMALLOCRESULT(PMPages);
  80
  81     // Load pages and initialize PMPages pointers
  82     uint8_t *ptr = (uint8_t *) PMPageData;
  83     for(i = 0; i < ChunksInFile; i++)
  84     {
  85         if(i >= PMSpriteStart && i < PMSoundStart || i == ChunksInFile - 1)
  86         {
  87             size_t offs = ptr - (uint8_t *) PMPageData;
  88
  89             // pad with zeros to make it 2-byte aligned
  90             if(offs & 1)
  91             {
  92                 *ptr++ = 0;
  93                 if(i == ChunksInFile - 1) PMSoundInfoPagePadded = true;
  94             }
  95         }
  96
  97         PMPages[i] = ptr;
  98
  99         if(!pageOffsets[i])
 100             continue;               // sparse page
 101
 102         // Use specified page length, when next page is sparse page.
 103         // Otherwise, calculate size from the offset difference between this and the next page.
 104         uint32_t size;
 105         if(!pageOffsets[i + 1]) size = pageLengths[i];
 106         else size = pageOffsets[i + 1] - pageOffsets[i];
 107
 108         fseek(file, pageOffsets[i], SEEK_SET);
 109         fread(ptr, 1, size, file);
 110         ptr += size;
 111     }
 112
 113     // last page points after page buffer
 114     PMPages[ChunksInFile] = ptr;
 115
 116     free(pageLengths);
 117     free(pageOffsets);
 118     fclose(file);
 119 }
 120
 121 void PM_Shutdown()
 122 {
 123     free(PMPages);
 124     free(PMPageData);
 125 }