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129 lines
3.6 KiB
C
129 lines
3.6 KiB
C
/*
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* COPYRIGHT: See COPYING in the top level directory
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* PROJECT: ReactOS kernel
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* PURPOSE: RLE compression
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* FILE: win32ss/gdi/eng/rlecomp.c
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* PROGRAMER: Jason Filby
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*/
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#include <win32k.h>
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#define NDEBUG
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#include <debug.h>
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enum Rle_EscapeCodes
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{
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RLE_EOL = 0, /* End of line */
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RLE_END = 1, /* End of bitmap */
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RLE_DELTA = 2 /* Delta */
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};
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VOID DecompressBitmap(SIZEL Size, BYTE *CompressedBits, BYTE *UncompressedBits,
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LONG Delta, ULONG Format, ULONG cjSizeImage)
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{
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INT x = 0, y = Size.cy - 1;
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INT i, c, c2, length;
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INT width = Size.cx, height = y;
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BYTE *begin = CompressedBits;
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BYTE *bits = CompressedBits;
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BYTE *temp;
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BOOL is4bpp = FALSE;
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if ((Format == BMF_4RLE) || (Format == BMF_4BPP))
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is4bpp = TRUE;
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else if ((Format != BMF_8RLE) && (Format != BMF_8BPP))
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return;
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_SEH2_TRY
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{
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while (y >= 0 && (bits - begin) <= cjSizeImage)
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{
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length = *bits++;
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if (length)
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{
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c = *bits++;
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for (i = 0; i < length; i++)
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{
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if (x >= width) break;
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temp = UncompressedBits + (height - y) * Delta;
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if (is4bpp)
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{
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temp += x / 2;
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if (i & 1)
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c2 = c & 0x0F;
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else
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c2 = c >> 4;
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if (x & 1)
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*temp |= c2;
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else
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*temp |= c2 << 4;
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}
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else
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{
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temp += x;
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*temp = c;
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}
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x++;
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}
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}
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else
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{
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length = *bits++;
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switch (length)
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{
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case RLE_EOL:
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x = 0;
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y--;
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break;
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case RLE_END:
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_SEH2_YIELD(return);
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case RLE_DELTA:
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x += *bits++;
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y -= *bits++;
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break;
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default:
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for (i = 0; i < length; i++)
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{
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if (!(is4bpp && i & 1))
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c = *bits++;
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if (x < width)
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{
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temp = UncompressedBits + (height - y) * Delta;
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if (is4bpp)
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{
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temp += x / 2;
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if (i & 1)
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c2 = c & 0x0F;
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else
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c2 = c >> 4;
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if (x & 1)
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*temp |= c2;
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else
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*temp |= c2 << 4;
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}
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else
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{
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temp += x;
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*temp = c;
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}
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x++;
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}
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}
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if ((bits - begin) & 1)
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{
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bits++;
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}
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}
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}
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}
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}
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_SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
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{
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DPRINT1("Decoding error\n");
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}
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_SEH2_END;
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return;
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}
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