libopenraw
ljpegdecompressor_priv.hpp
1 /*
2  * libopenraw - ljpegdecompressor_priv.h
3  *
4  * Copyright (C) 2007-2013 Hubert Figuiere
5  *
6  * This library is free software: you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public License
8  * as published by the Free Software Foundation, either version 3 of
9  * the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library. If not, see
18  * <http://www.gnu.org/licenses/>.
19  */
20 
21 #ifndef OR_INTERNALS_LJPEGDECOMPRESSOR_PRIV_H
22 #define OR_INTERNALS_LJPEGDECOMPRESSOR_PRIV_H
23 
24 #include <string.h>
25 
26 
27 
28 namespace OpenRaw {
29 namespace Internals {
30 
31 /*
32 * The following structure stores basic information about one component.
33 */
34 typedef struct JpegComponentInfo {
35  /*
36  * These values are fixed over the whole image.
37  * They are read from the SOF marker.
38  */
39  int16_t componentId; /* identifier for this component (0..255) */
40  int16_t componentIndex; /* its index in SOF or cPtr->compInfo[] */
41 
42  /*
43  * Downsampling is not normally used in lossless JPEG, although
44  * it is permitted by the JPEG standard (DIS). We set all sampling
45  * factors to 1 in this program.
46  */
47  int16_t hSampFactor; /* horizontal sampling factor */
48  int16_t vSampFactor; /* vertical sampling factor */
49 
50  /*
51  * Huffman table selector (0..3). The value may vary
52  * between scans. It is read from the SOS marker.
53  */
54  int16_t dcTblNo;
56 
57 
58 /*
59 * One of the following structures is created for each huffman coding
60 * table. We use the same structure for encoding and decoding, so there
61 * may be some extra fields for encoding that aren't used in the decoding
62 * and vice-versa.
63 */
64 struct HuffmanTable {
65  /*
66  * These two fields directly represent the contents of a JPEG DHT
67  * marker
68  */
69  uint8_t bits[17];
70  uint8_t huffval[256];
71 
72  /*
73  * This field is used only during compression. It's initialized
74  * FALSE when the table is created, and set TRUE when it's been
75  * output to the file.
76  */
77  bool sentTable;
78 
79  /*
80  * The remaining fields are computed from the above to allow more
81  * efficient coding and decoding. These fields should be considered
82  * private to the Huffman compression & decompression modules.
83  */
84  uint16_t ehufco[256];
85  char ehufsi[256];
86 
87  uint16_t mincode[17];
88  int32_t maxcode[18];
89  int16_t valptr[17];
90  int32_t numbits[256];
91  int32_t value[256];
92 };
93 
94 /*
95  * One of the following structures is used to pass around the
96  * decompression information.
97  */
99 {
100  // non copyable
101  DecompressInfo(const DecompressInfo&) = delete;
102  DecompressInfo& operator=(const DecompressInfo&) = delete;
103 
105  : imageWidth(0), imageHeight(0),
106  dataPrecision(0), compInfo(NULL),
107  numComponents(0),
108  compsInScan(0),
109  Ss(0), Pt(0),
110  restartInterval(0), restartInRows(0),
111  restartRowsToGo(0), nextRestartNum(0)
112 
113  {
114  memset(&curCompInfo, 0, sizeof(curCompInfo));
115  memset(&MCUmembership, 0, sizeof(MCUmembership));
116  memset(&dcHuffTblPtrs, 0, sizeof(dcHuffTblPtrs));
117  }
118  ~DecompressInfo()
119  {
120  int i;
121  for(i = 0; i < 4; i++) {
122  if(dcHuffTblPtrs[i]) {
123  free(dcHuffTblPtrs[i]);
124  }
125  }
126  if(compInfo) {
127  free(compInfo);
128  }
129  }
130  /*
131  * Image width, height, and image data precision (bits/sample)
132  * These fields are set by ReadFileHeader or ReadScanHeader
133  */
134  int32_t imageWidth;
135  int32_t imageHeight;
136  int32_t dataPrecision;
137 
138  /*
139  * compInfo[i] describes component that appears i'th in SOF
140  * numComponents is the # of color components in JPEG image.
141  */
142  JpegComponentInfo *compInfo;
143  int16_t numComponents;
144 
145  /*
146  * *curCompInfo[i] describes component that appears i'th in SOS.
147  * compsInScan is the # of color components in current scan.
148  */
149  JpegComponentInfo *curCompInfo[4];
150  int16_t compsInScan;
151 
152  /*
153  * MCUmembership[i] indexes the i'th component of MCU into the
154  * curCompInfo array.
155  */
156  int16_t MCUmembership[10];
157 
158  /*
159  * ptrs to Huffman coding tables, or NULL if not defined
160  */
161  HuffmanTable *dcHuffTblPtrs[4];
162 
163  /*
164  * prediction seletion value (PSV) and point transform parameter (Pt)
165  */
166  int32_t Ss;
167  int32_t Pt;
168 
169  /*
170  * In lossless JPEG, restart interval shall be an integer
171  * multiple of the number of MCU in a MCU row.
172  */
173  int32_t restartInterval;/* MCUs per restart interval, 0 = no restart */
174  int32_t restartInRows; /*if > 0, MCU rows per restart interval; 0 = no restart*/
175 
176  /*
177  * these fields are private data for the entropy decoder
178  */
179  int32_t restartRowsToGo; /* MCUs rows left in this restart interval */
180  int16_t nextRestartNum; /* # of next RSTn marker (0..7) */
181 };
182 
183 }
184 }
185 
186 
187 #endif
188 
CIFF is the container for CRW files. It is an attempt from Canon to make this a standard. I guess it failed.
Definition: arwfile.cpp:30