524 lines
16 KiB
C
524 lines
16 KiB
C
/****************************************************************************
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* apps/graphics/traveler/tools/libwld/wld_loadgif.c
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*
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* Copyright (C) 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/*************************************************************************
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* Included files
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*************************************************************************/
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "trv_types.h"
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#include "wld_mem.h"
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#include "wld_bitmaps.h"
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#include "wld_graphicfile.h"
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#include "wld_utils.h"
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/*************************************************************************
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* Pre-processor Definitions
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*************************************************************************/
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#define NEXTBYTE (*ptr++)
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#define IMAGESEP 0x2c
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#define GRAPHIC_EXT 0xf9
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#define PLAINTEXT_EXT 0x01
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#define APPLICATION_EXT 0xff
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#define COMMENT_EXT 0xfe
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#define START_EXTENSION 0x21
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#define INTERLACEMASK 0x40
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#define COLORMAPMASK 0x80
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/*************************************************************************
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* Private Data
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*************************************************************************/
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int BitOffset = 0, /* Bit Offset of next code */
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XC = 0, YC = 0, /* Output X and Y coords of current pixel */
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Pass = 0, /* Used by output routine if interlaced pic */
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OutCount = 0, /* Decompressor output 'stack count' */
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RWidth, RHeight, /* screen dimensions */
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Width, Height, /* image dimensions */
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LeftOfs, TopOfs, /* image offset */
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BitsPerPixel, /* Bits per pixel, read from GIF header */
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BytesPerScanline, /* bytes per scanline in output rwld_er */
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ColorMapSize, /* number of colors */
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Background, /* background color */
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CodeSize, /* Code size, read from GIF header */
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InitCodeSize, /* Starting code size, used during Clear */
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Code, /* Value returned by ReadCode */
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MaxCode, /* limiting value for current code size */
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ClearCode, /* GIF clear code */
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EOFCode, /* GIF end-of-information code */
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CurCode, OldCode, InCode, /* Decompressor variables */
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FirstFree, /* First free code, generated per GIF spec */
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FreeCode, /* Decompressor, next free slot in hash table*/
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FinChar, /* Decompressor variable */
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BitMask, /* AND mask for data size */
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ReadMask; /* Code AND mask for current code size */
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bool Interlace, HasColormap;
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bool Verbose = true;
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uint8_t *Image; /* The result array */
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uint8_t *RawGIF; /* The heap array to hold it, raw */
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uint8_t *Rwld_er; /* The rwld_er data stream, unblocked */
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/* The hash table used by the decompressor */
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int Prefix[4096];
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int Suffix[4096];
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/* An output array used by the decompressor */
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int OutCode[1025];
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/* The color map, read from the GIF header */
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uint8_t Red[256], Green[256], Blue[256], used[256];
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int numused;
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char *id87 = "GIF87a";
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char *id89 = "GIF89a";
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/*************************************************************************
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* Private Functions
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************************************************************************/
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/*************************************************************************
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* Name:
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* Description:
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* Fetch the next code from the rwld_er data stream. The codes can be
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* any length from 3 to 12 bits, packed into 8-bit bytes, so we have to
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* maintain our location in the Rwld_er array as a BIT Offset. We compute
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* the byte Offset into the rwld_er array by dividing this by 8, pick up
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* three bytes, compute the bit Offset into our 24-bit chunk, shift to
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* bring the desired code to the bottom, then mask it off and return it.
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************************************************************************/
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static int ReadCode(void)
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{
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int RawCode, ByteOffset;
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ByteOffset = BitOffset / 8;
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RawCode = Rwld_er[ByteOffset] + (0x100 * Rwld_er[ByteOffset + 1]);
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if (CodeSize >= 8)
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RawCode += (0x10000 * Rwld_er[ByteOffset + 2]);
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RawCode >>= (BitOffset % 8);
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BitOffset += CodeSize;
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return(RawCode & ReadMask);
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}
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static void AddToPixel(uint8_t Index)
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{
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if (YC<Height)
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*(Image + YC * BytesPerScanline + XC) = Index;
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if (!used[Index])
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{
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used[Index]=1;
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numused++;
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}
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/* Update the X-coordinate, and if it overflows, update the Y-coordinate */
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if (++XC == Width)
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{
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/* If a non-interlaced picture, just increment YC to the next scan line.
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* If it's interlaced, deal with the interlace as described in the GIF
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* spec. Put the decoded scan line out to the screen if we haven't gone
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* pwld_ the bottom of it
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*/
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XC = 0;
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if (!Interlace) YC++;
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else
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{
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switch (Pass)
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{
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case 0:
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YC += 8;
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if (YC >= Height)
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{
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Pass++;
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YC = 4;
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}
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break;
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case 1:
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YC += 8;
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if (YC >= Height)
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{
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Pass++;
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YC = 2;
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}
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break;
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case 2:
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YC += 4;
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if (YC >= Height)
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{
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Pass++;
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YC = 1;
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}
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break;
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case 3:
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YC += 2;
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break;
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default:
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break;
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}
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}
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}
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}
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/*************************************************************************
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* Public Functions
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************************************************************************/
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/*************************************************************************
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* Name:
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* Description:
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************************************************************************/
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GraphicFileType *wld_LoadGIF(FILE *fp, char *fname)
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{
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GraphicFileType *gfile;
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int filesize, numcols;
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register unsigned char ch, ch1;
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register uint8_t *ptr, *ptr1;
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register int i;
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short transparency = -1;
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BitOffset = 0;
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XC = YC = 0;
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Pass = 0;
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OutCount = 0;
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/* Find the size of the file */
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fseek(fp, 0L, 2);
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filesize = ftell(fp);
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fseek(fp, 0L, 0);
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if (!(ptr = RawGIF = (uint8_t *) malloc(filesize)))
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wld_fatal_error("not enough memory to read gif file");
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if (!(Rwld_er = (uint8_t *) malloc(filesize)))
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{
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free(ptr);
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wld_fatal_error("not enough memory to read gif file");
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}
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if (fread(ptr, filesize, 1, fp) != 1)
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wld_fatal_error("GIF data read failed");
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if (strncmp(ptr, id87, 6))
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if (strncmp(ptr, id89, 6))
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wld_fatal_error("not a GIF file");
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ptr += 6;
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/* Get variables from the GIF screen descriptor */
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ch = NEXTBYTE;
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RWidth = ch + 0x100 * NEXTBYTE; /* screen dimensions... not used. */
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ch = NEXTBYTE;
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RHeight = ch + 0x100 * NEXTBYTE;
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if (Verbose)
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fprintf(stderr, "screen dims: %dx%d.\n", RWidth, RHeight);
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ch = NEXTBYTE;
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HasColormap = ((ch & COLORMAPMASK) ? true : false);
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BitsPerPixel = (ch & 7) + 1;
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numcols = ColorMapSize = 1 << BitsPerPixel;
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BitMask = ColorMapSize - 1;
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Background = NEXTBYTE; /* background color... not used. */
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if (NEXTBYTE) /* supposed to be NULL */
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wld_fatal_error("corrupt GIF file (bad screen descriptor)");
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/* Read in global colormap. */
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if (HasColormap)
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{
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if (Verbose)
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fprintf(stderr, "%s is %dx%d, %d bits per pixel, (%d colors).\n",
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fname, RWidth,RHeight,BitsPerPixel, ColorMapSize);
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for (i = 0; i < ColorMapSize; i++)
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{
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Red[i] = NEXTBYTE;
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Green[i] = NEXTBYTE;
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Blue[i] = NEXTBYTE;
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used[i] = 0;
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}
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numused = 0;
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}
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/* look for image separator */
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for (ch = NEXTBYTE ; ch != IMAGESEP ; ch = NEXTBYTE)
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{
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i = ch;
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fprintf(stderr, "EXTENSION CHARACTER: %x\n", i);
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if (ch != START_EXTENSION)
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wld_fatal_error("corrupt GIF89a file");
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/* Handle image extensions */
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switch (ch = NEXTBYTE)
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{
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case GRAPHIC_EXT:
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ch = NEXTBYTE;
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if (ptr[0] & 0x1)
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{
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transparency = ptr[3]; /* transparent color index */
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fprintf(stderr, "transparency index: %i\n", transparency);
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}
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ptr += ch;
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break;
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case PLAINTEXT_EXT:
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break;
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case APPLICATION_EXT:
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break;
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case COMMENT_EXT:
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break;
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default:
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wld_fatal_error("invalid GIF89 extension");
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}
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while ((ch = NEXTBYTE))
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ptr += ch;
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}
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/* Now read in values from the image descriptor */
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ch = NEXTBYTE;
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LeftOfs = ch + 0x100 * NEXTBYTE;
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ch = NEXTBYTE;
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TopOfs = ch + 0x100 * NEXTBYTE;
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ch = NEXTBYTE;
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Width = ch + 0x100 * NEXTBYTE;
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ch = NEXTBYTE;
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Height = ch + 0x100 * NEXTBYTE;
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Interlace = ((NEXTBYTE & INTERLACEMASK) ? true : false);
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if (Verbose)
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fprintf(stderr, "Reading a %d by %d %sinterlaced image...",
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Width, Height, (Interlace) ? "" : "non-");
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gfile = wld_new_graphicfile();
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gfile->palette = (RGBColor*)wld_malloc(sizeof(RGBColor) * ColorMapSize);
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for (i = 0; i < ColorMapSize; i++)
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{
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gfile->palette[i].red = Red[i];
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gfile->palette[i].green = Green[i];
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gfile->palette[i].blue = Blue[i];
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}
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gfile->bitmap = (uint8_t*)wld_malloc(Width * Height);
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gfile->type = gfPaletted;
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gfile->width = Width;
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gfile->height = Height;
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gfile->transparent_entry = transparency;
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/* Note that I ignore the possible existence of a local color map.
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* I'm told there aren't many files around that use them, and the spec
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* says it's defined for future use. This could lead to an error
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* reading some files.
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*/
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/* Start reading the rwld_er data. First we get the intial code size
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* and compute decompressor constant values, based on this code size.
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*/
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CodeSize = NEXTBYTE;
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ClearCode = (1 << CodeSize);
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EOFCode = ClearCode + 1;
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FreeCode = FirstFree = ClearCode + 2;
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/* The GIF spec has it that the code size is the code size used to
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* compute the above values is the code size given in the file, but the
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* code size used in compression/decompression is the code size given in
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* the file plus one. (thus the ++).
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*/
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CodeSize++;
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InitCodeSize = CodeSize;
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MaxCode = (1 << CodeSize);
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ReadMask = MaxCode - 1;
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/* Read the rwld_er data. Here we just transpose it from the GIF array
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* to the Rwld_er array, turning it from a series of blocks into one long
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* data stream, which makes life much easier for ReadCode().
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*/
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ptr1 = Rwld_er;
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do
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{
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ch = ch1 = NEXTBYTE;
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while (ch--) *ptr1++ = NEXTBYTE;
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if ((ptr1 - Rwld_er) > filesize)
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wld_fatal_error("corrupt GIF file (unblock)");
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}
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while(ch1);
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free(RawGIF); /* We're done with the raw data now... */
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if (Verbose)
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{
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fprintf(stderr, "done.\n");
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fprintf(stderr, "Decompressing...");
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}
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Image = gfile->bitmap;
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BytesPerScanline = Width;
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/* Decompress the file, continuing until you see the GIF EOF code.
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* One obvious enhancement is to add checking for corrupt files here.
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*/
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Code = ReadCode();
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while (Code != EOFCode)
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{
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/* Clear code sets everything back to its initial value, then reads the
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* immediately subsequent code as uncompressed data.
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*/
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if (Code == ClearCode)
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{
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CodeSize = InitCodeSize;
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MaxCode = (1 << CodeSize);
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ReadMask = MaxCode - 1;
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FreeCode = FirstFree;
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CurCode = OldCode = Code = ReadCode();
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FinChar = CurCode & BitMask;
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AddToPixel(FinChar);
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}
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else
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{
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/* If not a clear code, then must be data: save same as CurCode
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* and InCode
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*/
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CurCode = InCode = Code;
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/* If greater or equal to FreeCode, not in the hash table yet;
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* repeat the lwld_ character decoded
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*/
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if (CurCode >= FreeCode)
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{
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CurCode = OldCode;
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OutCode[OutCount++] = FinChar;
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}
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/* Unless this code is raw data, pursue the chain pointed to
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* by CurCode through the hash table to its end; each code
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* in the chain puts its associated output code on the output
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* queue.
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*/
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while (CurCode > BitMask)
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{
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if (OutCount > 1024)
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{
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fprintf(stderr,"\nCorrupt GIF file (OutCount)!\n");
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exit(-1);
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}
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OutCode[OutCount++] = Suffix[CurCode];
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CurCode = Prefix[CurCode];
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}
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/* The lwld_ code in the chain is treated as raw data. */
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FinChar = CurCode & BitMask;
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OutCode[OutCount++] = FinChar;
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/* Now we put the data out to the Output routine.
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* It's been stacked LIFO, so deal with it that way...
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*/
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for (i = OutCount - 1; i >= 0; i--)
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AddToPixel(OutCode[i]);
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OutCount = 0;
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/* Build the hash table on-the-fly. No table is stored in the file */
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Prefix[FreeCode] = OldCode;
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Suffix[FreeCode] = FinChar;
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OldCode = InCode;
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/* Point to the next slot in the table. If we exceed the current
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* MaxCode value, increment the code size unless it's already 12.
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* If it is, do nothing: the next code decompressed better be
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* CLEAR
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*/
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FreeCode++;
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if (FreeCode >= MaxCode)
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{
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if (CodeSize < 12)
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{
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CodeSize++;
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MaxCode *= 2;
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ReadMask = (1 << CodeSize) - 1;
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}
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}
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}
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Code = ReadCode();
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}
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free(Rwld_er);
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if (Verbose)
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fprintf(stderr, "done.\n");
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else
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fprintf(stderr,"(of which %d are used)\n",numused);
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return gfile;
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}
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