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#include "wl_def.h"
int ChunksInFile;
int PMSpriteStart;
int PMSoundStart;
bool PMSoundInfoPagePadded = false;
// holds the whole VSWAP
uint32_t *PMPageData;
size_t PMPageDataSize;
// ChunksInFile+1 pointers to page starts.
// The last pointer points one byte after the last page.
uint8_t **PMPages;
void PM_Startup()
{
char fname[13 + sizeof(DATADIR)] = DATADIR "vswap.";
strcat(fname,extension);
FILE *file = fopen(fname,"rb");
if(!file)
CA_CannotOpen(fname);
ChunksInFile = 0;
fread(&ChunksInFile, sizeof(word), 1, file);
PMSpriteStart = 0;
fread(&PMSpriteStart, sizeof(word), 1, file);
PMSoundStart = 0;
fread(&PMSoundStart, sizeof(word), 1, file);
uint32_t* pageOffsets = (uint32_t *) malloc((ChunksInFile + 1) * sizeof(int32_t));
CHECKMALLOCRESULT(pageOffsets);
fread(pageOffsets, sizeof(uint32_t), ChunksInFile, file);
word *pageLengths = (word *) malloc(ChunksInFile * sizeof(word));
CHECKMALLOCRESULT(pageLengths);
fread(pageLengths, sizeof(word), ChunksInFile, file);
fseek(file, 0, SEEK_END);
long fileSize = ftell(file);
long pageDataSize = fileSize - pageOffsets[0];
if(pageDataSize > (size_t) -1)
Quit("The page file \"%s\" is too large!", fname);
pageOffsets[ChunksInFile] = fileSize;
uint32_t dataStart = pageOffsets[0];
int i;
// Check that all pageOffsets are valid
for(i = 0; i < ChunksInFile; i++)
{
if(!pageOffsets[i]) continue; // sparse page
if(pageOffsets[i] < dataStart || pageOffsets[i] >= (size_t) fileSize)
Quit("Illegal page offset for page %i: %u (filesize: %u)",
i, pageOffsets[i], fileSize);
}
// Calculate total amount of padding needed for sprites and sound info page
int alignPadding = 0;
for(i = PMSpriteStart; i < PMSoundStart; i++)
{
if(!pageOffsets[i]) continue; // sparse page
uint32_t offs = pageOffsets[i] - dataStart + alignPadding;
if(offs & 1)
alignPadding++;
}
if((pageOffsets[ChunksInFile - 1] - dataStart + alignPadding) & 1)
alignPadding++;
PMPageDataSize = (size_t) pageDataSize + alignPadding;
PMPageData = (uint32_t *) malloc(PMPageDataSize);
CHECKMALLOCRESULT(PMPageData);
PMPages = (uint8_t **) malloc((ChunksInFile + 1) * sizeof(uint8_t *));
CHECKMALLOCRESULT(PMPages);
// Load pages and initialize PMPages pointers
uint8_t *ptr = (uint8_t *) PMPageData;
for(i = 0; i < ChunksInFile; i++)
{
if((i >= PMSpriteStart && i < PMSoundStart) || i == ChunksInFile - 1)
{
size_t offs = ptr - (uint8_t *) PMPageData;
// pad with zeros to make it 2-byte aligned
if(offs & 1)
{
*ptr++ = 0;
if(i == ChunksInFile - 1) PMSoundInfoPagePadded = true;
}
}
PMPages[i] = ptr;
if(!pageOffsets[i])
continue; // sparse page
// Use specified page length, when next page is sparse page.
// Otherwise, calculate size from the offset difference between this and the next page.
uint32_t size;
if(!pageOffsets[i + 1]) size = pageLengths[i];
else size = pageOffsets[i + 1] - pageOffsets[i];
fseek(file, pageOffsets[i], SEEK_SET);
fread(ptr, 1, size, file);
ptr += size;
}
// last page points after page buffer
PMPages[ChunksInFile] = ptr;
free(pageLengths);
free(pageOffsets);
fclose(file);
}
void PM_Shutdown()
{
free(PMPages);
free(PMPageData);
}
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