1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
/*
* jpeg.h --
*
* Basic jpeg data structure definitions.
*
*
* Copyright (C) 1991, 1992, Thomas G. Lane.
* Part of the Independent JPEG Group's software.
* See the file Copyright for more details.
*
* Copyright (c) 1993 Brian C. Smith, The Regents of the University
* of California
* All rights reserved.
*
* Copyright (c) 1994 Kongji Huang and Brian C. Smith.
* Cornell University
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL CORNELL UNIVERSITY BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF CORNELL
* UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* CORNELL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND CORNELL UNIVERSITY HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#ifndef _JPEG
#define _JPEG
typedef unsigned char Uchar;
typedef unsigned short Ushort;
typedef unsigned int Uint;
/*
* 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.
*/
short componentId; /* identifier for this component (0..255) */
short 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.
*/
short hSampFactor; /* horizontal sampling factor */
short vSampFactor; /* vertical sampling factor */
/*
* Huffman table selector (0..3). The value may vary
* between scans. It is read from the SOS marker.
*/
short 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.
*/
typedef struct HuffmanTable {
/*
* These two fields directly represent the contents of a JPEG DHT
* marker
*/
Uchar bits[17];
Uchar 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.
*/
int 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.
*/
Ushort ehufco[256];
char ehufsi[256];
Ushort mincode[17];
int maxcode[18];
short valptr[17];
int numbits[256];
int value[256];
} HuffmanTable;
/*
* One of the following structures is used to pass around the
* compression information.
*/
typedef struct CompressInfo {
/*
* Image width, height, and image data precision (bits/sample)
*/
int imageWidth;
int imageHeight;
int dataPrecision;
/*
* compInfo[i] describes component that appears i'th in SOF
* numComponents is the # of color components in JPEG image.
*/
JpegComponentInfo *compInfo;
short numComponents;
/*
* *curCompInfo[i] describes component that appears i'th in SOS.
* compsInScan is the # of color components in current scan.
*/
JpegComponentInfo *curCompInfo[4];
short compsInScan;
/*
* MCUmembership[i] indexes the i'th component of MCU into the
* curCompInfo array.
*/
short MCUmembership[10];
/*
* Pointers to Huffman coding tables, or NULL if not defined.
*/
HuffmanTable *dcHuffTblPtrs[4];
/*
* prediction seletion value (PSV) and point transform parameter (Pt)
*/
int Ss;
int Pt;
/*
* In lossless JPEG, restart interval shall be an integer
* multiple of the number of MCU in a MCU row.
*/
int restartInRows; /*if > 0, MCU rows per restart interval; 0 = no restart*/
/*
* These fields are private data for the entropy encoder
*/
int restartRowsToGo; /* MCUs rows left in this restart interval */
short nextRestartNum; /* # of next RSTn marker (0..7) */
} CompressInfo;
/*
* One of the following structures is used to pass around the
* decompression information.
*/
typedef struct DecompressInfo {
/*
* Image width, height, and image data precision (bits/sample)
* These fields are set by ReadFileHeader or ReadScanHeader
*/
int imageWidth;
int imageHeight;
int dataPrecision;
/*
* compInfo[i] describes component that appears i'th in SOF
* numComponents is the # of color components in JPEG image.
*/
JpegComponentInfo *compInfo;
short numComponents;
/*
* *curCompInfo[i] describes component that appears i'th in SOS.
* compsInScan is the # of color components in current scan.
*/
JpegComponentInfo *curCompInfo[4];
short compsInScan;
/*
* MCUmembership[i] indexes the i'th component of MCU into the
* curCompInfo array.
*/
short MCUmembership[10];
/*
* ptrs to Huffman coding tables, or NULL if not defined
*/
HuffmanTable *dcHuffTblPtrs[4];
/*
* prediction seletion value (PSV) and point transform parameter (Pt)
*/
int Ss;
int Pt;
/*
* In lossless JPEG, restart interval shall be an integer
* multiple of the number of MCU in a MCU row.
*/
int restartInterval;/* MCUs per restart interval, 0 = no restart */
int restartInRows; /*if > 0, MCU rows per restart interval; 0 = no restart*/
/*
* these fields are private data for the entropy decoder
*/
int restartRowsToGo; /* MCUs rows left in this restart interval */
short nextRestartNum; /* # of next RSTn marker (0..7) */
} DecompressInfo;
/*
*--------------------------------------------------------------
*
* swap --
*
* Swap the contents stored in a and b.
* "type" is the variable type of a and b.
*
* Results:
* The values in a and b are swapped.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
#define swap(type,a,b) {type c; c=(a); (a)=(b); (b)=c;}
#define MEMSET(s,c,n) memset((void *)(s),(int)(c),(int)(n))
#define MEMCPY(s1,s2,n) memcpy((void *)(s1),(void *)(s2),(int)(n))
/*
* Lossless JPEG specifies data precision to be from 2 to 16 bits/sample.
*/
#define MinPrecisionBits 2
#define MaxPrecisionBits 16
#define MinPrecisionValue 2
#define MaxPrecisionValue 65535
#endif /* _JPEG */
|
