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402 | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include "pnghelper.hxx"
#include <sal/macros.h>
#include <zlib.h>
using namespace pdfi;
// checksum helpers, courtesy of libpng.org
/* Table of CRCs of all 8-bit messages. */
sal_uInt32 PngHelper::crc_table[256];
/* Flag: has the table been computed? Initially false. */
bool PngHelper::bCRCTableInit = true;
/* Make the table for a fast CRC. */
void PngHelper::initCRCTable()
{
for (sal_uInt32 n = 0; n < 256; n++)
{
sal_uInt32 c = n;
for (int k = 0; k < 8; k++)
{
if (c & 1)
c = 0xedb88320L ^ (c >> 1);
else
c = c >> 1;
}
crc_table[n] = c;
}
bCRCTableInit = false;
}
/* Update a running CRC with the bytes buf[0..len-1]--the CRC
should be initialized to all 1's, and the transmitted value
is the 1's complement of the final running CRC (see the
crc() routine below)). */
void PngHelper::updateCRC( sal_uInt32& io_rCRC, const sal_uInt8* i_pBuf, size_t i_nLen )
{
if( bCRCTableInit )
initCRCTable();
sal_uInt32 nCRC = io_rCRC;
for( size_t n = 0; n < i_nLen; n++ )
nCRC = crc_table[(nCRC ^ i_pBuf[n]) & 0xff] ^ (nCRC >> 8);
io_rCRC = nCRC;
}
sal_uInt32 PngHelper::getCRC( const sal_uInt8* i_pBuf, size_t i_nLen )
{
sal_uInt32 nCRC = 0xffffffff;
updateCRC( nCRC, i_pBuf, i_nLen );
return nCRC ^ 0xffffffff;
}
sal_uInt32 PngHelper::deflateBuffer( const Output_t* i_pBuf, size_t i_nLen, OutputBuffer& o_rOut )
{
size_t nOrigSize = o_rOut.size();
// prepare z stream
z_stream aStream;
aStream.zalloc = Z_NULL;
aStream.zfree = Z_NULL;
aStream.opaque = Z_NULL;
deflateInit( &aStream, Z_BEST_COMPRESSION );
aStream.avail_in = uInt(i_nLen);
aStream.next_in = const_cast<Bytef*>(i_pBuf);
sal_uInt8 aOutBuf[ 32768 ];
do
{
aStream.avail_out = sizeof( aOutBuf );
aStream.next_out = aOutBuf;
if( deflate( &aStream, Z_FINISH ) == Z_STREAM_ERROR )
{
deflateEnd( &aStream );
// scrap the data of this broken stream
o_rOut.resize( nOrigSize );
return 0;
}
// append compressed bytes
sal_uInt32 nCompressedBytes = sizeof( aOutBuf ) - aStream.avail_out;
if( nCompressedBytes )
o_rOut.insert( o_rOut.end(), aOutBuf, aOutBuf+nCompressedBytes );
} while( aStream.avail_out == 0 );
// cleanup
deflateEnd( &aStream );
return sal_uInt32( o_rOut.size() - nOrigSize );
}
void PngHelper::appendFileHeader( OutputBuffer& o_rOutputBuf )
{
static const unsigned char aHeader[] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
o_rOutputBuf.insert( o_rOutputBuf.end(), aHeader, aHeader + SAL_N_ELEMENTS(aHeader) );
}
size_t PngHelper::startChunk( const char* pChunkName, OutputBuffer& o_rOutputBuf )
{
size_t nIndex = sal_uInt32( o_rOutputBuf.size() );
o_rOutputBuf.insert( o_rOutputBuf.end(), 4, Output_t(0) );
o_rOutputBuf.push_back( pChunkName[0] );
o_rOutputBuf.push_back( pChunkName[1] );
o_rOutputBuf.push_back( pChunkName[2] );
o_rOutputBuf.push_back( pChunkName[3] );
return nIndex;
}
void PngHelper::set( sal_uInt32 i_nValue, OutputBuffer& o_rOutputBuf, size_t i_nIndex )
{
o_rOutputBuf[ i_nIndex ] = (i_nValue & 0xff000000) >> 24;
o_rOutputBuf[ i_nIndex+1 ] = (i_nValue & 0x00ff0000) >> 16;
o_rOutputBuf[ i_nIndex+2 ] = (i_nValue & 0x0000ff00) >> 8;
o_rOutputBuf[ i_nIndex+3 ] = (i_nValue & 0x000000ff);
}
void PngHelper::endChunk( size_t nStart, OutputBuffer& o_rOutputBuf )
{
if( nStart+8 > o_rOutputBuf.size() )
return; // something broken is going on
// update chunk length
size_t nLen = o_rOutputBuf.size() - nStart;
sal_uInt32 nDataLen = sal_uInt32(nLen)-8;
set( nDataLen, o_rOutputBuf, nStart );
// append chunk crc
sal_uInt32 nChunkCRC = getCRC( reinterpret_cast<sal_uInt8*>(&o_rOutputBuf[nStart+4]), nLen-4 );
append( nChunkCRC, o_rOutputBuf );
}
void PngHelper::appendIHDR( OutputBuffer& o_rOutputBuf, int width, int height, int depth, int colortype )
{
size_t nStart = startChunk( "IHDR", o_rOutputBuf );
append( width, o_rOutputBuf );
append( height, o_rOutputBuf );
o_rOutputBuf.push_back( Output_t(depth) );
o_rOutputBuf.push_back( Output_t(colortype) );
o_rOutputBuf.push_back( 0 ); // compression method deflate
o_rOutputBuf.push_back( 0 ); // filtering method 0 (default)
o_rOutputBuf.push_back( 0 ); // no interlacing
endChunk( nStart, o_rOutputBuf );
}
void PngHelper::appendIEND( OutputBuffer& o_rOutputBuf )
{
size_t nStart = startChunk( "IEND", o_rOutputBuf );
endChunk( nStart, o_rOutputBuf );
}
void PngHelper::createPng( OutputBuffer& o_rOutputBuf,
Stream* str,
int width,
int height,
GfxRGB const & zeroColor,
GfxRGB const & oneColor,
bool bIsMask
)
{
appendFileHeader( o_rOutputBuf );
appendIHDR( o_rOutputBuf, width, height, 1, 3 );
// write palette
size_t nIdx = startChunk( "PLTE", o_rOutputBuf );
// write colors 0 and 1
o_rOutputBuf.push_back(colToByte(zeroColor.r));
o_rOutputBuf.push_back(colToByte(zeroColor.g));
o_rOutputBuf.push_back(colToByte(zeroColor.b));
o_rOutputBuf.push_back(colToByte(oneColor.r));
o_rOutputBuf.push_back(colToByte(oneColor.g));
o_rOutputBuf.push_back(colToByte(oneColor.b));
// end PLTE chunk
endChunk( nIdx, o_rOutputBuf );
if( bIsMask )
{
// write tRNS chunk
nIdx = startChunk( "tRNS", o_rOutputBuf );
o_rOutputBuf.push_back( 0xff );
o_rOutputBuf.push_back( 0 );
// end tRNS chunk
endChunk( nIdx, o_rOutputBuf );
}
// create scan line data buffer
OutputBuffer aScanlines;
int nLineSize = (width + 7)/8;
aScanlines.reserve( nLineSize * height + height );
str->reset();
for( int y = 0; y < height; y++ )
{
// determine filter type (none) for this scanline
aScanlines.push_back( 0 );
for( int x = 0; x < nLineSize; x++ )
aScanlines.push_back( str->getChar() );
}
// begin IDAT chunk for scanline data
nIdx = startChunk( "IDAT", o_rOutputBuf );
// compress scanlines
deflateBuffer( aScanlines.data(), aScanlines.size(), o_rOutputBuf );
// end IDAT chunk
endChunk( nIdx, o_rOutputBuf );
// output IEND
appendIEND( o_rOutputBuf );
}
void PngHelper::createPng( OutputBuffer& o_rOutputBuf,
Stream* str,
int width, int height, GfxImageColorMap* colorMap,
Stream* maskStr,
int maskWidth, int maskHeight, GfxImageColorMap* maskColorMap )
{
appendFileHeader( o_rOutputBuf );
appendIHDR( o_rOutputBuf, width, height, 8, 6 ); // RGBA image
// initialize stream
unsigned char *p, *pm;<--- The scope of the variable 'p' can be reduced. [+]The scope of the variable 'p' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
int i = 0;
if (x) {
// it's safe to move 'int i = 0;' here
for (int n = 0; n < 10; ++n) {
// it is possible but not safe to move 'int i = 0;' here
do_something(&i);
}
}
}
When you see this message it is always safe to reduce the variable scope 1 level. <--- The scope of the variable 'pm' can be reduced. [+]The scope of the variable 'pm' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
int i = 0;
if (x) {
// it's safe to move 'int i = 0;' here
for (int n = 0; n < 10; ++n) {
// it is possible but not safe to move 'int i = 0;' here
do_something(&i);
}
}
}
When you see this message it is always safe to reduce the variable scope 1 level.
GfxRGB rgb;
GfxGray alpha;
std::unique_ptr<ImageStream> imgStr(
new ImageStream(str,
width,
colorMap->getNumPixelComps(),
colorMap->getBits()));
imgStr->reset();
// create scan line data buffer
OutputBuffer aScanlines;
aScanlines.reserve( width*height*4 + height );
for( int y=0; y<height; ++y)
{
aScanlines.push_back( 0 );
p = imgStr->getLine();
for( int x=0; x<width; ++x)
{
colorMap->getRGB(p, &rgb);
aScanlines.push_back(colToByte(rgb.r));
aScanlines.push_back(colToByte(rgb.g));
aScanlines.push_back(colToByte(rgb.b));
aScanlines.push_back( 0xff );
p +=colorMap->getNumPixelComps();
}
}
// now fill in the mask data
// CAUTION: originally this was done in one single loop
// it caused merry chaos; the reason is that maskStr and str are
// not independent streams, it happens that reading one advances
// the other, too. Hence the two passes are imperative !
// initialize mask stream
std::unique_ptr<ImageStream> imgStrMask(
new ImageStream(maskStr,
maskWidth,
maskColorMap->getNumPixelComps(),
maskColorMap->getBits()));
imgStrMask->reset();
for( int y = 0; y < maskHeight; ++y )
{
pm = imgStrMask->getLine();
for( int x = 0; x < maskWidth; ++x )
{
maskColorMap->getGray(pm,&alpha);
pm += maskColorMap->getNumPixelComps();
int nIndex = (y*height/maskHeight) * (width*4+1) + // mapped line
(x*width/maskWidth)*4 + 1 + 3 // mapped column
;
aScanlines[ nIndex ] = colToByte(alpha);
}
}
imgStr.reset();
imgStrMask.reset();
// begind IDAT chunk for scanline data
size_t nIdx = startChunk( "IDAT", o_rOutputBuf );
// compress scanlines
deflateBuffer( aScanlines.data(), aScanlines.size(), o_rOutputBuf );
// end IDAT chunk
endChunk( nIdx, o_rOutputBuf );
// output IEND
appendIEND( o_rOutputBuf );
}
// one bit mask; 0 bits opaque
void PngHelper::createPng( OutputBuffer& o_rOutputBuf,
Stream* str,
int width, int height, GfxImageColorMap* colorMap,
Stream* maskStr,
int maskWidth, int maskHeight,
bool maskInvert
)
{
appendFileHeader( o_rOutputBuf );
appendIHDR( o_rOutputBuf, width, height, 8, 6 ); // RGBA image
// initialize stream
unsigned char *p;<--- The scope of the variable 'p' can be reduced. [+]The scope of the variable 'p' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
int i = 0;
if (x) {
// it's safe to move 'int i = 0;' here
for (int n = 0; n < 10; ++n) {
// it is possible but not safe to move 'int i = 0;' here
do_something(&i);
}
}
}
When you see this message it is always safe to reduce the variable scope 1 level.
GfxRGB rgb;
std::unique_ptr<ImageStream> imgStr(
new ImageStream(str,
width,
colorMap->getNumPixelComps(),
colorMap->getBits()));
imgStr->reset();
// create scan line data buffer
OutputBuffer aScanlines;
aScanlines.reserve( width*height*4 + height );
for( int y=0; y<height; ++y)
{
aScanlines.push_back( 0 );
p = imgStr->getLine();
for( int x=0; x<width; ++x)
{
colorMap->getRGB(p, &rgb);
aScanlines.push_back(colToByte(rgb.r));
aScanlines.push_back(colToByte(rgb.g));
aScanlines.push_back(colToByte(rgb.b));
aScanlines.push_back( 0xff );
p +=colorMap->getNumPixelComps();
}
}
// now fill in the mask data
// CAUTION: originally this was done in one single loop
// it caused merry chaos; the reason is that maskStr and str are
// not independent streams, it happens that reading one advances
// the other, too. Hence the two passes are imperative !
// initialize mask stream
std::unique_ptr<ImageStream> imgStrMask(
new ImageStream(maskStr, maskWidth, 1, 1));
imgStrMask->reset();
for( int y = 0; y < maskHeight; ++y )
{
for( int x = 0; x < maskWidth; ++x )
{
unsigned char aPixel = 0;
imgStrMask->getPixel( &aPixel );
int nIndex = (y*height/maskHeight) * (width*4+1) + // mapped line
(x*width/maskWidth)*4 + 1 + 3 // mapped column
;
if( maskInvert )
aScanlines[ nIndex ] = aPixel ? 0xff : 0x00;
else
aScanlines[ nIndex ] = aPixel ? 0x00 : 0xff;
}
}
imgStr.reset();
imgStrMask.reset();
// begind IDAT chunk for scanline data
size_t nIdx = startChunk( "IDAT", o_rOutputBuf );
// compress scanlines
deflateBuffer( aScanlines.data(), aScanlines.size(), o_rOutputBuf );
// end IDAT chunk
endChunk( nIdx, o_rOutputBuf );
// output IEND
appendIEND( o_rOutputBuf );
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|