/
jutils.c
227 lines (197 loc) · 6.58 KB
/
jutils.c
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
/*
* jutils.c
*
* Copyright (C) 1991-1996, Thomas G. Lane.
* Modified 2009-2011 by Guido Vollbeding.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains tables and miscellaneous utility routines needed
* for both compression and decompression.
* Note we prefix all global names with "j" to minimize conflicts with
* a surrounding application.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/*
* jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
* of a DCT block read in natural order (left to right, top to bottom).
*/
#if 0 /* This table is not actually needed in v6a */
const int jpeg_zigzag_order[DCTSIZE2] = {
0, 1, 5, 6, 14, 15, 27, 28,
2, 4, 7, 13, 16, 26, 29, 42,
3, 8, 12, 17, 25, 30, 41, 43,
9, 11, 18, 24, 31, 40, 44, 53,
10, 19, 23, 32, 39, 45, 52, 54,
20, 22, 33, 38, 46, 51, 55, 60,
21, 34, 37, 47, 50, 56, 59, 61,
35, 36, 48, 49, 57, 58, 62, 63
};
#endif
/*
* jpeg_natural_order[i] is the natural-order position of the i'th element
* of zigzag order.
*
* When reading corrupted data, the Huffman decoders could attempt
* to reference an entry beyond the end of this array (if the decoded
* zero run length reaches past the end of the block). To prevent
* wild stores without adding an inner-loop test, we put some extra
* "63"s after the real entries. This will cause the extra coefficient
* to be stored in location 63 of the block, not somewhere random.
* The worst case would be a run-length of 15, which means we need 16
* fake entries.
*/
const int jpeg_natural_order[DCTSIZE2+16] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order7[7*7+16] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 14, 21, 28, 35,
42, 49, 50, 43, 36, 29, 22, 30,
37, 44, 51, 52, 45, 38, 46, 53,
54,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order6[6*6+16] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 41, 34, 27,
20, 13, 21, 28, 35, 42, 43, 36,
29, 37, 44, 45,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order5[5*5+16] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 12,
19, 26, 33, 34, 27, 20, 28, 35,
36,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order4[4*4+16] = {
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 25, 18, 11, 19, 26, 27,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order3[3*3+16] = {
0, 1, 8, 16, 9, 2, 10, 17,
18,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
const int jpeg_natural_order2[2*2+16] = {
0, 1, 8, 9,
63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
63, 63, 63, 63, 63, 63, 63, 63
};
/*
* Arithmetic utilities
*/
GLOBAL(long)
jdiv_round_up (long a, long b)
/* Compute a/b rounded up to next integer, ie, ceil(a/b) */
/* Assumes a >= 0, b > 0 */
{
return (a + b - 1L) / b;
}
GLOBAL(long)
jround_up (long a, long b)
/* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
/* Assumes a >= 0, b > 0 */
{
a += b - 1L;
return a - (a % b);
}
/* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
* and coefficient-block arrays. This won't work on 80x86 because the arrays
* are FAR and we're assuming a small-pointer memory model. However, some
* DOS compilers provide far-pointer versions of memcpy() and memset() even
* in the small-model libraries. These will be used if USE_FMEM is defined.
* Otherwise, the routines below do it the hard way. (The performance cost
* is not all that great, because these routines aren't very heavily used.)
*/
#ifndef NEED_FAR_POINTERS /* normal case, same as regular macro */
#define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
#else /* 80x86 case, define if we can */
#ifdef USE_FMEM
#define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
#else
/* This function is for use by the FMEMZERO macro defined in jpegint.h.
* Do not call this function directly, use the FMEMZERO macro instead.
*/
GLOBAL(void)
jzero_far (void FAR * target, size_t bytestozero)
/* Zero out a chunk of FAR memory. */
/* This might be sample-array data, block-array data, or alloc_large data. */
{
register char FAR * ptr = (char FAR *) target;
register size_t count;
for (count = bytestozero; count > 0; count--) {
*ptr++ = 0;
}
}
#endif
#endif
GLOBAL(void)
jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
JSAMPARRAY output_array, int dest_row,
int num_rows, JDIMENSION num_cols)
/* Copy some rows of samples from one place to another.
* num_rows rows are copied from input_array[source_row++]
* to output_array[dest_row++]; these areas may overlap for duplication.
* The source and destination arrays must be at least as wide as num_cols.
*/
{
register JSAMPROW inptr, outptr;
#ifdef FMEMCOPY
register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
#else
register JDIMENSION count;
#endif
register int row;
input_array += source_row;
output_array += dest_row;
for (row = num_rows; row > 0; row--) {
inptr = *input_array++;
outptr = *output_array++;
#ifdef FMEMCOPY
FMEMCOPY(outptr, inptr, count);
#else
for (count = num_cols; count > 0; count--)
*outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */
#endif
}
}
GLOBAL(void)
jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
JDIMENSION num_blocks)
/* Copy a row of coefficient blocks from one place to another. */
{
#ifdef FMEMCOPY
FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
#else
register JCOEFPTR inptr, outptr;
register long count;
inptr = (JCOEFPTR) input_row;
outptr = (JCOEFPTR) output_row;
for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
*outptr++ = *inptr++;
}
#endif
}