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