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-rw-r--r--tools/gifconv/decompress.c320
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diff --git a/tools/gifconv/decompress.c b/tools/gifconv/decompress.c
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-/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
- * Copyright by the Board of Trustees of the University of Illinois. *
- * All rights reserved. *
- * *
- * This file is part of HDF5. The full HDF5 copyright notice, including *
- * terms governing use, modification, and redistribution, is contained in *
- * the files COPYING and Copyright.html. COPYING can be found at the root *
- * of the source code distribution tree; Copyright.html can be found at the *
- * root level of an installed copy of the electronic HDF5 document set and *
- * is linked from the top-level documents page. It can also be found at *
- * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html. If you do not have *
- * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
- * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "gif.h"
-
-#define NEXTBYTE (*ptr++)
-
-#define IMAGESEP 0x2c
-#define INTERLACEMASK 0x40
-#define COLORMAPMASK 0x80
-
-WORD iWIDE, iHIGH, eWIDE, eHIGH, expand, numcols, strip, nostrip;
-unsigned long cols[256];
-char *cmd;
-
-FILE *fp;
-
-static WORD
- XC = 0, YC = 0, /* Output X and Y coords of current pixel */
- InitCodeSize, /* Starting code size, used during Clear */
- CodeSize, /* Code size, read from GIF header */
- BytesPerScanline, /* Bytes per scanline in output raster */
- IWidth, IHeight; /* image dimensions */
-static int
- BitOffset = 0, /* Bit Offset of next code */
- Pass = 0, /* Used by output routine if WORDerlaced pic */
- OutCount = 0, /* Decompressor output 'stack count' */
- Code, /* Value returned by ReadCode */
- MaxCode, /* limiting value for current code size */
- ClearCode, /* GIF clear code */
- EOFCode, /* GIF end-of-information code */
- CurCode, OldCode, InCode, /* Decompressor variables */
- FirstFree, /* First free code, generated per GIF spec */
- FreeCode, /* Decompressor, next free slot in hash table */
- FinChar, /* Decompressor variable */
- DataMask, /* AND mask for data size */
- ReadMask; /* Code AND mask for current code size */
-
-/*MODIFICATIONS*/
-BYTE tempbyte[10];
-BYTE * tempBYTEptr[10];
-WORD tempint[10];
-WORD ImageCount = 0;
-/*END MODIFICATION*/
-
-boolean Interlace, HasColormap;
-
-BYTE *Image; /* The result array */
-BYTE *RawGIF; /* The heap array to hold it, raw */
-BYTE *Raster; /* The raster data stream, unblocked */
-
-/* The hash table used by the decompressor */
-
-int Prefix[4096];
-int Suffix[4096];
-
-/* An output array used by the decompressor */
-
-int OutCode[1025];
-
-/* The color map, read from the GIF header */
-
-int numused;
-
-/*
- * Fetch the next code from the raster data stream. The codes can be any
- * length from 3 to 12 bits, packed WORDo 8-bit BYTEs, so we have to maWORDain
- * our location in the Raster array as a BIT Offset. We compute the BYTE
- * Offset WORDo the raster array by dividing this by 8, pick up three BYTEs,
- * compute the bit Offset WORDo our 24-bit chunk, shift to bring the desired
- * code to the bottom, then mask it off and return it.
- */
-static int
-ReadCode(void)
-{
- int RawCode, ByteOffset;
-
- ByteOffset = BitOffset / 8;
- RawCode = Raster[ByteOffset] + (0x100 * Raster[ByteOffset + 1]);
-
- if (CodeSize >= 8)
- RawCode += (0x10000 * Raster[ByteOffset + 2]);
-
- RawCode >>= (BitOffset % 8);
- BitOffset += CodeSize;
- return (RawCode & ReadMask);
-}
-
-static void
-AddToPixel(BYTE Index)
-{
- if (YC<IHeight)
- *(Image + YC * BytesPerScanline + XC) = Index;
-
-
-
- /* Update the X-coordinate, and if it overflows, update the
- * Y-coordinate */
- if (++XC == IWidth) {
- /*
- * If a non-WORDerlaced picture, just increment YC to the next scan
- * line. If it's WORDerlaced, deal with the WORDerlace as described
- * in the GIF spec. Put the decoded scan line out to the screen if we
- * haven't gone past the bottom of it.
- */
- XC = 0;
-
- if (!Interlace) {
- YC++;
- } else {
- switch (Pass) {
- case 0:
- YC += 8;
-
- if (YC >= IHeight) {
- Pass++;
- YC = 4;
- }
-
- break;
- case 1:
- YC += 8;
-
- if (YC >= IHeight) {
- Pass++;
- YC = 2;
- }
-
- break;
- case 2:
- YC += 4;
-
- if (YC >= IHeight) {
- Pass++;
- YC = 1;
- }
-
- break;
- case 3:
- YC += 2;
- break;
- default:
- break;
- }
- }
- }
-}
-
-/* Main routine. Convert a GIF image to an HDF image */
-
-BYTE *
-Decompress(GIFIMAGEDESC *GifImageDesc, GIFHEAD *GifHead)
-{
- int i;
-
- XC = 0;
- YC = 0;
- Pass = 0;
- OutCount = 0;
- BitOffset = 0;
-
- DataMask = (1 << ((GifHead->PackedField & 0x07) +1)) -1;
- Raster = GifImageDesc->GIFImage;
-
- /* Check for image seperator */
-
- /* Now read in values from the image descriptor */
- IWidth = GifImageDesc->ImageWidth;
- IHeight = GifImageDesc->ImageHeight;
- Interlace = GifImageDesc->PackedField & 0x40;
-
- /*
- * Note that I ignore the possible existence of a local color map. I'm
- * told there aren't many files around that use them, and the spec says
- * it's defined for future use. This could lead to an error reading some
- * files.
- */
-
- /*
- * Start reading the raster data. First we get the WORDial code size and
- * compute decompressor constant values, based on this code size.
- */
-
- CodeSize = GifImageDesc->CodeSize;
- ClearCode = (1 << CodeSize);
- EOFCode = ClearCode + 1;
- FreeCode = FirstFree = ClearCode + 2;
-
- /*
- * The GIF spec has it that the code size is the code size used to compute
- * the above values is the code size given in the file, but the code size
- * used in compression/decompression is the code size given in the file
- * plus one. (thus the ++).
- */
-
- CodeSize++;
- InitCodeSize = CodeSize;
- MaxCode = (1 << CodeSize);
- ReadMask = MaxCode - 1;
-
- /*
- * Read the raster data. Here we just transpose it from the GIF array to
- * the Raster array, turning it from a series of blocks WORDo one long
- * data stream, which makes life much easier for ReadCode().
- */
-
- /* Allocate the Image */
-
- if (!(Image = (BYTE *)malloc((size_t)IWidth*(size_t)IHeight))) {
- printf("Out of memory");
- exit(-1);
- }
-
- BytesPerScanline = IWidth;
-
- /*
- * Decompress the file, continuing until you see the GIF EOF code. One
- * obvious enhancement is to add checking for corrupt files here.
- */
-
- Code = ReadCode();
-
- while (Code != EOFCode) {
- /*
- * Clear code sets everything back to its initial value, then reads
- * the immediately subsequent code as uncompressed data.
- */
- if (Code == ClearCode) {
- CodeSize = InitCodeSize;
- MaxCode = (1 << CodeSize);
- ReadMask = MaxCode - 1;
- FreeCode = FirstFree;
- CurCode = OldCode = Code = ReadCode();
- FinChar = CurCode & DataMask;
- AddToPixel((BYTE)FinChar);
- } else {
- /*
- * If not a clear code, then must be data: save same as CurCode
- * and InCode
- */
- CurCode = InCode = Code;
-
- /*
- * If greater or equal to FreeCode, not in the hash table yet;
- * repeat the last character decoded
- */
- if (CurCode >= FreeCode) {
- CurCode = OldCode;
- OutCode[OutCount++] = FinChar;
- }
-
- /*
- * Unless this code is raw data, pursue the chain poWORDed to by
- * CurCode through the hash table to its end; each code in the
- * chain puts its associated output code on the output queue.
- */
- while (CurCode > DataMask) {
- if (OutCount > 1024) {
- /*return error message*/
- }
-
- OutCode[OutCount++] = Suffix[CurCode];
- CurCode = Prefix[CurCode];
- }
-
- /* The last code in the chain is treated as raw data. */
- FinChar = CurCode & DataMask;
- OutCode[OutCount++] = FinChar;
-
- /*
- * Now we put the data out to the Output routine. It's been
- * stacked LIFO, so deal with it that way...
- */
- for (i = OutCount - 1; i >= 0; i--)
- AddToPixel((BYTE)OutCode[i]);
-
- OutCount = 0;
-
- /*
- * Build the hash table on-the-fly. No table is stored in the
- * file.
- */
- Prefix[FreeCode] = OldCode;
- Suffix[FreeCode] = FinChar;
- OldCode = InCode;
-
- /*
- * PoWORD to the next slot in the table. If we exceed the current
- * MaxCode value, increment the code size unless it's already 12.
- * If it is, do nothing: the next code decompressed better be
- * CLEAR
- */
- FreeCode++;
-
- if (FreeCode >= MaxCode)
- if (CodeSize < 12) {
- CodeSize++;
- MaxCode *= 2;
- ReadMask = (1 << CodeSize) - 1;
- }
- }
-
- Code = ReadCode();
- }
-
- return Image;
-}
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