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// =================================================================================================
// ADOBE SYSTEMS INCORPORATED
// Copyright 2002-2007 Adobe Systems Incorporated
// All Rights Reserved
//
// NOTICE: Adobe permits you to use, modify, and distribute this file in accordance with the terms
// of the Adobe license agreement accompanying it.
//
// Derived from PNG_Support.cpp by Ian Jacobi
// =================================================================================================
#include "GIF_Support.hpp"
#include <string.h>
typedef std::basic_string<unsigned char> filebuffer;
// Don't need CRC.
namespace GIF_Support
{
// This only really counts for extension blocks.
enum blockType {
bGraphicControl = 0xF9,
bComment = 0xFE,
bPlainText = 0x01,
bApplication = 0xFF,
// Hacky. Don't like the following, but there's no easy way.
bImage = 0x2C,
bExtension = 0x21,
bTerminator = 0x3B,
bHeader = 0x47
};
// =============================================================================================
long OpenGIF ( LFA_FileRef fileRef, BlockState & inOutBlockState )
{
XMP_Uns64 pos = 0;
unsigned char name;
XMP_Uns32 len;
BlockData newBlock;
pos = LFA_Seek ( fileRef, 0, SEEK_SET );
// header needs to be a block, mostly for our safe write.
pos = ReadHeader ( fileRef );
if (pos < 13) return 0;
newBlock.pos = 0;
newBlock.len = pos;
newBlock.type = bHeader;
inOutBlockState.blocks.push_back(newBlock);
// read first and following blocks
while ( ReadBlock ( fileRef, inOutBlockState, &name, &len, pos) ) {}
return inOutBlockState.blocks.size();
}
// =============================================================================================
long ReadHeader ( LFA_FileRef fileRef )
{
long bytesRead;
long headerSize;
long tableSize = 0;
long bytesPerColor = 0;
unsigned char buffer[768];
headerSize = 0;
bytesRead = LFA_Read ( fileRef, buffer, GIF_SIGNATURE_LEN );
if ( bytesRead != GIF_SIGNATURE_LEN ) return 0;
if ( memcmp ( buffer, GIF_SIGNATURE_DATA, GIF_SIGNATURE_LEN) != 0 ) return 0;
headerSize += bytesRead;
bytesRead = LFA_Read ( fileRef, buffer, 3 );
if ( bytesRead != 3 ) return 0;
if ( memcmp ( buffer, "87a", 3 ) != 0 && memcmp ( buffer, "89a", 3 ) != 0 ) return 0;
headerSize += bytesRead;
bytesRead = LFA_Read ( fileRef, buffer, 4 );
if ( bytesRead != 4 ) return 0;
headerSize += bytesRead;
bytesRead = LFA_Read ( fileRef, buffer, 3 );
if ( bytesRead != 3 ) return 0;
headerSize += bytesRead;
if ( buffer[0] & 0x80 ) tableSize = (1 << ((buffer[0] & 0x07) + 1)) * 3;
bytesRead = LFA_Read ( fileRef, buffer, tableSize );
if ( bytesRead != tableSize ) return 0;
headerSize += bytesRead;
return headerSize;
}
// =============================================================================================
bool ReadBlock ( LFA_FileRef fileRef, BlockState & inOutBlockState, unsigned char * blockType, XMP_Uns32 * blockLength, XMP_Uns64 & inOutPosition )
{
try
{
XMP_Uns64 startPosition = inOutPosition;
long bytesRead;
long blockSize;
unsigned char buffer[768];
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
if ( buffer[0] == bImage )
{
// Image is a special case.
long tableSize = 0;
bytesRead = LFA_Read ( fileRef, buffer, 4 );
if ( bytesRead != 4 ) return false;
inOutPosition += 4;
bytesRead = LFA_Read ( fileRef, buffer, 4 );
if ( bytesRead != 4 ) return false;
inOutPosition += 4;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
if ( buffer[0] & 0x80 ) tableSize = (1 << ((buffer[0] & 0x07) + 1)) * 3;
bytesRead = LFA_Read ( fileRef, buffer, tableSize );
if ( bytesRead != tableSize ) return 0;
inOutPosition += tableSize;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
tableSize = buffer[0];
while ( tableSize != 0x00 )
{
bytesRead = LFA_Read ( fileRef, buffer, tableSize );
if ( bytesRead != tableSize ) return false;
inOutPosition += tableSize;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
tableSize = buffer[0];
}
BlockData newBlock;
newBlock.pos = startPosition;
newBlock.len = inOutPosition - startPosition;
newBlock.type = bImage;
inOutBlockState.blocks.push_back ( newBlock );
}
else if ( buffer[0] == bExtension )
{
unsigned char type;
long tableSize = 0;
BlockData newBlock;
newBlock.pos = startPosition;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
type = buffer[0];
newBlock.type = type;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
tableSize = buffer[0];
while ( tableSize != 0x00 )
{
bytesRead = LFA_Read ( fileRef, buffer, tableSize );
if ( bytesRead != tableSize ) return false;
inOutPosition += tableSize;
if ( inOutPosition - startPosition == 14 && type == bApplication )
{
// Check for XMP identifier...
CheckApplicationBlockHeader ( fileRef, inOutBlockState, newBlock, inOutPosition );
if ( newBlock.xmp == true )
{
newBlock.len = inOutPosition - startPosition;
inOutBlockState.blocks.push_back ( newBlock );
return true;
}
}
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
tableSize = buffer[0];
}
newBlock.len = inOutPosition - startPosition;
inOutBlockState.blocks.push_back ( newBlock );
}
else if ( buffer[0] == bTerminator )
{
BlockData newBlock;
newBlock.pos = startPosition;
newBlock.len = 1;
newBlock.type = buffer[0];
inOutBlockState.blocks.push_back ( newBlock );
}
} catch ( ... ) {
return false;
}
return true;
}
// =============================================================================================
bool WriteXMPBlock ( LFA_FileRef fileRef, XMP_Uns32 len, const char* inBuffer )
{
bool ret = false;
unsigned long datalen = (APPLICATION_HEADER_LEN + len + MAGIC_TRAILER_LEN);
unsigned char* buffer = new unsigned char[datalen];
try
{
size_t pos = 0;
memcpy(&buffer[pos], APPLICATION_HEADER_DATA, APPLICATION_HEADER_LEN);
pos += APPLICATION_HEADER_LEN;
memcpy(&buffer[pos], inBuffer, len);
pos += len;
memcpy(&buffer[pos], MAGIC_TRAILER_DATA, MAGIC_TRAILER_LEN);
LFA_Write(fileRef, buffer, datalen);
ret = true;
}
catch ( ... ) {}
delete [] buffer;
return ret;
}
// =============================================================================================
bool CopyBlock ( LFA_FileRef sourceRef, LFA_FileRef destRef, BlockData& block )
{
try
{
LFA_Seek (sourceRef, block.pos, SEEK_SET );
LFA_Copy (sourceRef, destRef, (block.len));
} catch ( ... ) {
return false;
}
return true;
}
// =============================================================================================
// Don't need CRC.
// =============================================================================================
unsigned long CheckApplicationBlockHeader ( LFA_FileRef fileRef, BlockState& inOutBlockState, BlockData& inOutBlockData, XMP_Uns64& inOutPosition )
{
try
{
LFA_Seek(fileRef, (inOutBlockData.pos), SEEK_SET);
unsigned char buffer[256];
long bytesRead = LFA_Read ( fileRef, buffer, APPLICATION_HEADER_LEN );
if (bytesRead == APPLICATION_HEADER_LEN)
{
if (memcmp(buffer, APPLICATION_HEADER_DATA, APPLICATION_HEADER_LEN) == 0)
{
// We still have to go through all of the data...
long tableSize = 0;
long xmpSize;
inOutPosition = inOutBlockData.pos + APPLICATION_HEADER_LEN;
inOutBlockState.xmpPos = inOutPosition;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return 0;
inOutPosition += 1;
tableSize = buffer[0];
while ( tableSize != 0x00 )
{
bytesRead = LFA_Read ( fileRef, buffer, tableSize );
if ( bytesRead != tableSize ) return false;
inOutPosition += tableSize;
bytesRead = LFA_Read ( fileRef, buffer, 1 );
if ( bytesRead != 1 ) return false;
inOutPosition += 1;
tableSize = buffer[0];
}
inOutBlockState.xmpLen = inOutPosition - inOutBlockData.pos - APPLICATION_HEADER_LEN - MAGIC_TRAILER_LEN;
inOutBlockState.xmpBlock = inOutBlockData;
inOutBlockData.xmp = true;
}
}
}
catch ( ... ) {}
return 0;
}
bool ReadBuffer ( LFA_FileRef fileRef, XMP_Uns64 & pos, XMP_Uns32 len, char * outBuffer )
{
try
{
if ( (fileRef == 0) || (outBuffer == 0) ) return false;
LFA_Seek (fileRef, pos, SEEK_SET );
long bytesRead = LFA_Read ( fileRef, outBuffer, len );
if ( XMP_Uns32(bytesRead) != len ) return false;
return true;
}
catch ( ... ) {}
return false;
}
bool WriteBuffer ( LFA_FileRef fileRef, XMP_Uns64 & pos, XMP_Uns32 len, const char * inBuffer )
{
try
{
if ( (fileRef == 0) || (inBuffer == 0) ) return false;
LFA_Seek (fileRef, pos, SEEK_SET );
LFA_Write( fileRef, inBuffer, len );
return true;
}
catch ( ... ) {}
return false;
}
} // namespace GIF_Support
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