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/*
* libopenraw - ljpegdecompressor_priv.h
*
* Copyright (C) 2007 Hubert Figuiere
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#ifndef __OPENRAW_LJPEGDECOMPRESSOR_PRIV_H__
#define __OPENRAW_LJPEGDECOMPRESSOR_PRIV_H__
#include <string.h>
namespace OpenRaw {
namespace Internals {
/*
* The following structure stores basic information about one component.
*/
typedef struct JpegComponentInfo {
/*
* These values are fixed over the whole image.
* They are read from the SOF marker.
*/
int16_t componentId; /* identifier for this component (0..255) */
int16_t componentIndex; /* its index in SOF or cPtr->compInfo[] */
/*
* Downsampling is not normally used in lossless JPEG, although
* it is permitted by the JPEG standard (DIS). We set all sampling
* factors to 1 in this program.
*/
int16_t hSampFactor; /* horizontal sampling factor */
int16_t vSampFactor; /* vertical sampling factor */
/*
* Huffman table selector (0..3). The value may vary
* between scans. It is read from the SOS marker.
*/
int16_t dcTblNo;
} JpegComponentInfo;
/*
* One of the following structures is created for each huffman coding
* table. We use the same structure for encoding and decoding, so there
* may be some extra fields for encoding that aren't used in the decoding
* and vice-versa.
*/
struct HuffmanTable {
/*
* These two fields directly represent the contents of a JPEG DHT
* marker
*/
uint8_t bits[17];
uint8_t huffval[256];
/*
* This field is used only during compression. It's initialized
* FALSE when the table is created, and set TRUE when it's been
* output to the file.
*/
bool sentTable;
/*
* The remaining fields are computed from the above to allow more
* efficient coding and decoding. These fields should be considered
* private to the Huffman compression & decompression modules.
*/
uint16_t ehufco[256];
char ehufsi[256];
uint16_t mincode[17];
int32_t maxcode[18];
int16_t valptr[17];
int32_t numbits[256];
int32_t value[256];
};
/*
* One of the following structures is used to pass around the
* decompression information.
*/
struct DecompressInfo
: public boost::noncopyable
{
DecompressInfo()
: imageWidth(0), imageHeight(0),
dataPrecision(0), compInfo(NULL),
numComponents(0),
compsInScan(0),
Ss(0), Pt(0),
restartInterval(0), restartInRows(0),
restartRowsToGo(0), nextRestartNum(0)
{
memset(&curCompInfo, 0, sizeof(curCompInfo));
memset(&MCUmembership, 0, sizeof(MCUmembership));
memset(&dcHuffTblPtrs, 0, sizeof(dcHuffTblPtrs));
}
~DecompressInfo()
{
int i;
for(i = 0; i < 4; i++) {
if(dcHuffTblPtrs[i]) {
free(dcHuffTblPtrs[i]);
}
}
if(compInfo) {
free(compInfo);
}
}
/*
* Image width, height, and image data precision (bits/sample)
* These fields are set by ReadFileHeader or ReadScanHeader
*/
int32_t imageWidth;
int32_t imageHeight;
int32_t dataPrecision;
/*
* compInfo[i] describes component that appears i'th in SOF
* numComponents is the # of color components in JPEG image.
*/
JpegComponentInfo *compInfo;
int16_t numComponents;
/*
* *curCompInfo[i] describes component that appears i'th in SOS.
* compsInScan is the # of color components in current scan.
*/
JpegComponentInfo *curCompInfo[4];
int16_t compsInScan;
/*
* MCUmembership[i] indexes the i'th component of MCU into the
* curCompInfo array.
*/
int16_t MCUmembership[10];
/*
* ptrs to Huffman coding tables, or NULL if not defined
*/
HuffmanTable *dcHuffTblPtrs[4];
/*
* prediction seletion value (PSV) and point transform parameter (Pt)
*/
int32_t Ss;
int32_t Pt;
/*
* In lossless JPEG, restart interval shall be an integer
* multiple of the number of MCU in a MCU row.
*/
int32_t restartInterval;/* MCUs per restart interval, 0 = no restart */
int32_t restartInRows; /*if > 0, MCU rows per restart interval; 0 = no restart*/
/*
* these fields are private data for the entropy decoder
*/
int32_t restartRowsToGo; /* MCUs rows left in this restart interval */
int16_t nextRestartNum; /* # of next RSTn marker (0..7) */
private:
/** private copy constructor to make sure it is not called */
DecompressInfo(const DecompressInfo& f);
/** private = operator to make sure it is never called */
DecompressInfo & operator=(const DecompressInfo&);
};
}
}
#endif
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