473 lines
12 KiB
C++
473 lines
12 KiB
C++
////////////////////////////////////////////////////////////////////////////
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//
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// Crytek Engine Source File.
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// Copyright (C), Crytek Studios, 2001.
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// -------------------------------------------------------------------------
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// File name: imagegif.cpp
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// Version: v1.00
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// Created: 15/3/2002 by Timur.
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// Compilers: Visual C++ 7.0
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// Description:
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// -------------------------------------------------------------------------
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// History:
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//
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////////////////////////////////////////////////////////////////////////////
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#include "StdAfx.h"
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#include "ImageGif.h"
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#include "CryFile.h"
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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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#define CHK(x) x
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#pragma pack(push,1)
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struct SRGBcolor
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{
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uchar red, green, blue;
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};
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struct SRGBPixel
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{
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uchar red, green, blue, alpha;
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};
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#pragma pack(pop)
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static 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 raster */
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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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static bool Interlace, HasColormap;
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static SRGBPixel *Image; /* The result array */
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static SRGBcolor* Palette; /* The palette that is used */
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static uchar* IndexImage;
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static uchar *Raster; /* The raster data stream, unblocked */
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static uchar used[256];
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static int numused;
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const char *id87 = "GIF87a";
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const char *id89 = "GIF89a";
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static int log2 (int);
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/* Fetch the next code from the raster 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 Raster array as a BIT Offset. We compute
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* the uchar Offset into the raster 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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inline 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 = Raster[ByteOffset] + (0x100 * Raster[ByteOffset + 1]);
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if (CodeSize >= 8)
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RawCode += (0x10000 * Raster[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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inline void AddToPixel (uchar Index)
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{
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if (YC<Height)
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{
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SRGBPixel* p = Image + YC * BytesPerScanline + XC;
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p->red = Palette[Index].red;
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p->green = Palette[Index].green;
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p->blue = Palette[Index].blue;
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p->alpha = 0;
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IndexImage[YC * BytesPerScanline + XC] = Index;
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}
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if (!used[Index]) { used[Index]=1; numused++; }
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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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* past 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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bool CImageGif::Load( const CString &fileName,CImage &outImage )
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{
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std::vector<uchar> data;
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CCryFile file;
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if (!file.Open( fileName,"rb" ))
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{
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CLogFile::FormatLine( "File not found %s",(const char*)fileName );
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return false;
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}
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long filesize = file.GetLength();
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data.resize(filesize);
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uchar* ptr = &data[0];
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file.Read( ptr,filesize );
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/* Detect if this is a GIF file */
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if (strncmp ((char*)ptr, "GIF87a", 6) && strncmp ((char*)ptr, "GIF89a", 6))
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{
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CLogFile::FormatLine( "Bad GIF file format %s",(const char*)fileName );
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return false;
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}
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int numcols;
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register unsigned char ch, ch1;
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register uchar *ptr1;
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register int i;
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short transparency = -1;
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/* The hash table used by the decompressor */
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int* Prefix;
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int* Suffix;
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/* An output array used by the decompressor */
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int* OutCode;
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CHK (Prefix = new int [4096]);
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CHK (Suffix = new int [4096]);
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CHK (OutCode = new int [1025]);
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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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Palette = NULL;
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CHK (Raster = new uchar [filesize]);
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if (strncmp((char *) ptr, id87, 6))
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if (strncmp((char *) ptr, id89, 6))
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{
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CLogFile::FormatLine( "Bad GIF file format %s",(const char*)fileName );
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return false;
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}
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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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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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{
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CLogFile::FormatLine( "Bad GIF file format %s",(const char*)fileName );
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return false;
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}
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/* Read in global colormap. */
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SRGBcolor mspPal[1024];
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if (HasColormap)
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{
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for (i = 0; i < ColorMapSize; i++)
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{
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mspPal[i].red = NEXTBYTE;
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mspPal[i].green = NEXTBYTE;
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mspPal[i].blue = NEXTBYTE;
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used[i] = 0;
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}
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Palette = mspPal;
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numused = 0;
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} /* else no colormap in GIF file */
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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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if (ch != START_EXTENSION)
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{
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CLogFile::FormatLine( "Bad GIF file format %s",(const char*)fileName );
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return false;
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}
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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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transparency = ptr[3]; /* transparent color index */
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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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{
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CLogFile::FormatLine( "Invalid GIF89 extension %s",(const char*)fileName );
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return false;
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}
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}
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while ((ch = NEXTBYTE)) ptr += ch;
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}
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//if (transparency >= 0)
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//mfSet_transparency(transparency);
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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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TImage<uchar> outImageIndex;
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// Set the dimensions which will also allocate the image data
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// buffer.
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outImage.Allocate(Width,Height);
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//mfSet_dimensions (Width, Height);
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Image = (SRGBPixel*)outImage.GetData();
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outImageIndex.Allocate(Width,Height);
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IndexImage = outImageIndex.GetData();
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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 raster 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 raster data. Here we just transpose it from the GIF array
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* to the Raster 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 = Raster;
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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 - Raster) > filesize)
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{
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CLogFile::FormatLine( "Corrupted GIF file (unblock) %s",(const char*)fileName );
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return false;
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}
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}
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while (ch1);
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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 and InCode */
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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 last 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 by CurCode
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* through the hash table to its end; each code in the chain puts its
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* associated output code on the output 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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CLogFile::FormatLine( "Corrupted GIF file (OutCount) %s",(const char*)fileName );
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return false;
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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 last 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. If it
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* is, do nothing: the next code decompressed better be 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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//cleanup:
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if (Raster) { CHK (delete [] Raster); }
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if (Prefix) { CHK (delete [] Prefix); }
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if (Suffix) { CHK (delete [] Suffix); }
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if (OutCode) { CHK (delete [] OutCode); }
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return true;
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} |