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jutils.c
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1 /*
2  * jutils.c
3  *
4  * Copyright (C) 1991-1996, Thomas G. Lane.
5  * Modified 2009-2011 by Guido Vollbeding.
6  * This file is part of the Independent JPEG Group's software.
7  * For conditions of distribution and use, see the accompanying README file.
8  *
9  * This file contains tables and miscellaneous utility routines needed
10  * for both compression and decompression.
11  * Note we prefix all global names with "j" to minimize conflicts with
12  * a surrounding application.
13  */
14 
15 #define JPEG_INTERNALS
16 #include "jinclude.h"
17 #include "jpeglib.h"
18 
19 
20 /*
21  * jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
22  * of a DCT block read in natural order (left to right, top to bottom).
23  */
24 
25 #if 0 /* This table is not actually needed in v6a */
26 
27 const int jpeg_zigzag_order[DCTSIZE2] = {
28  0, 1, 5, 6, 14, 15, 27, 28,
29  2, 4, 7, 13, 16, 26, 29, 42,
30  3, 8, 12, 17, 25, 30, 41, 43,
31  9, 11, 18, 24, 31, 40, 44, 53,
32  10, 19, 23, 32, 39, 45, 52, 54,
33  20, 22, 33, 38, 46, 51, 55, 60,
34  21, 34, 37, 47, 50, 56, 59, 61,
35  35, 36, 48, 49, 57, 58, 62, 63
36 };
37 
38 #endif
39 
40 /*
41  * jpeg_natural_order[i] is the natural-order position of the i'th element
42  * of zigzag order.
43  *
44  * When reading corrupted data, the Huffman decoders could attempt
45  * to reference an entry beyond the end of this array (if the decoded
46  * zero run length reaches past the end of the block). To prevent
47  * wild stores without adding an inner-loop test, we put some extra
48  * "63"s after the real entries. This will cause the extra coefficient
49  * to be stored in location 63 of the block, not somewhere random.
50  * The worst case would be a run-length of 15, which means we need 16
51  * fake entries.
52  */
53 
54 const int jpeg_natural_order[DCTSIZE2+16] = {
55  0, 1, 8, 16, 9, 2, 3, 10,
56  17, 24, 32, 25, 18, 11, 4, 5,
57  12, 19, 26, 33, 40, 48, 41, 34,
58  27, 20, 13, 6, 7, 14, 21, 28,
59  35, 42, 49, 56, 57, 50, 43, 36,
60  29, 22, 15, 23, 30, 37, 44, 51,
61  58, 59, 52, 45, 38, 31, 39, 46,
62  53, 60, 61, 54, 47, 55, 62, 63,
63  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
64  63, 63, 63, 63, 63, 63, 63, 63
65 };
66 
67 const int jpeg_natural_order7[7*7+16] = {
68  0, 1, 8, 16, 9, 2, 3, 10,
69  17, 24, 32, 25, 18, 11, 4, 5,
70  12, 19, 26, 33, 40, 48, 41, 34,
71  27, 20, 13, 6, 14, 21, 28, 35,
72  42, 49, 50, 43, 36, 29, 22, 30,
73  37, 44, 51, 52, 45, 38, 46, 53,
74  54,
75  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
76  63, 63, 63, 63, 63, 63, 63, 63
77 };
78 
79 const int jpeg_natural_order6[6*6+16] = {
80  0, 1, 8, 16, 9, 2, 3, 10,
81  17, 24, 32, 25, 18, 11, 4, 5,
82  12, 19, 26, 33, 40, 41, 34, 27,
83  20, 13, 21, 28, 35, 42, 43, 36,
84  29, 37, 44, 45,
85  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
86  63, 63, 63, 63, 63, 63, 63, 63
87 };
88 
89 const int jpeg_natural_order5[5*5+16] = {
90  0, 1, 8, 16, 9, 2, 3, 10,
91  17, 24, 32, 25, 18, 11, 4, 12,
92  19, 26, 33, 34, 27, 20, 28, 35,
93  36,
94  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
95  63, 63, 63, 63, 63, 63, 63, 63
96 };
97 
98 const int jpeg_natural_order4[4*4+16] = {
99  0, 1, 8, 16, 9, 2, 3, 10,
100  17, 24, 25, 18, 11, 19, 26, 27,
101  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
102  63, 63, 63, 63, 63, 63, 63, 63
103 };
104 
105 const int jpeg_natural_order3[3*3+16] = {
106  0, 1, 8, 16, 9, 2, 10, 17,
107  18,
108  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
109  63, 63, 63, 63, 63, 63, 63, 63
110 };
111 
112 const int jpeg_natural_order2[2*2+16] = {
113  0, 1, 8, 9,
114  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
115  63, 63, 63, 63, 63, 63, 63, 63
116 };
117 
118 
119 /*
120  * Arithmetic utilities
121  */
122 
123 GLOBAL(long)
124 jdiv_round_up (long a, long b)
125 /* Compute a/b rounded up to next integer, ie, ceil(a/b) */
126 /* Assumes a >= 0, b > 0 */
127 {
128  return (a + b - 1L) / b;
129 }
130 
131 
132 GLOBAL(long)
133 jround_up (long a, long b)
134 /* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
135 /* Assumes a >= 0, b > 0 */
136 {
137  a += b - 1L;
138  return a - (a % b);
139 }
140 
141 
142 /* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
143  * and coefficient-block arrays. This won't work on 80x86 because the arrays
144  * are FAR and we're assuming a small-pointer memory model. However, some
145  * DOS compilers provide far-pointer versions of memcpy() and memset() even
146  * in the small-model libraries. These will be used if USE_FMEM is defined.
147  * Otherwise, the routines below do it the hard way. (The performance cost
148  * is not all that great, because these routines aren't very heavily used.)
149  */
150 
151 #ifndef NEED_FAR_POINTERS /* normal case, same as regular macro */
152 #define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
153 #else /* 80x86 case, define if we can */
154 #ifdef USE_FMEM
155 #define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
156 #else
157 /* This function is for use by the FMEMZERO macro defined in jpegint.h.
158  * Do not call this function directly, use the FMEMZERO macro instead.
159  */
160 GLOBAL(void)
161 jzero_far (void FAR * target, size_t bytestozero)
162 /* Zero out a chunk of FAR memory. */
163 /* This might be sample-array data, block-array data, or alloc_large data. */
164 {
165  register char FAR * ptr = (char FAR *) target;
166  register size_t count;
167 
168  for (count = bytestozero; count > 0; count--) {
169  *ptr++ = 0;
170  }
171 }
172 #endif
173 #endif
174 
175 
176 GLOBAL(void)
180 /* Copy some rows of samples from one place to another.
181  * num_rows rows are copied from input_array[source_row++]
182  * to output_array[dest_row++]; these areas may overlap for duplication.
183  * The source and destination arrays must be at least as wide as num_cols.
184  */
185 {
186  register JSAMPROW inptr, outptr;
187 #ifdef FMEMCOPY
188  register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
189 #else
190  register JDIMENSION count;
191 #endif
192  register int row;
193 
194  input_array += source_row;
196 
197  for (row = num_rows; row > 0; row--) {
198  inptr = *input_array++;
199  outptr = *output_array++;
200 #ifdef FMEMCOPY
201  FMEMCOPY(outptr, inptr, count);
202 #else
203  for (count = num_cols; count > 0; count--)
204  *outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */
205 #endif
206  }
207 }
208 
209 
210 GLOBAL(void)
213 /* Copy a row of coefficient blocks from one place to another. */
214 {
215 #ifdef FMEMCOPY
216  FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
217 #else
218  register JCOEFPTR inptr, outptr;
219  register long count;
220 
221  inptr = (JCOEFPTR) input_row;
222  outptr = (JCOEFPTR) output_row;
223  for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
224  *outptr++ = *inptr++;
225  }
226 #endif
227 }
char JSAMPLE
Definition: jmorecfg.h:74
JSAMPLE FAR * JSAMPROW
Definition: jpeglib.h:75
GLuint GLuint GLsizei count
Definition: gl.h:1545
short JCOEF
Definition: jmorecfg.h:151
const int jpeg_natural_order2[2 *2+16]
Definition: jutils.c:112
const int jpeg_natural_order7[7 *7+16]
Definition: jutils.c:67
#define SIZEOF(_ar)
Definition: calc.h:97
#define FAR
Definition: guiddef.h:36
jround_up(long a, long b)
Definition: jutils.c:133
static PVOID ptr
Definition: dispmode.c:27
#define FMEMCOPY(dest, src, size)
Definition: jutils.c:152
int JSAMPARRAY int dest_row
Definition: jpegint.h:412
#define DCTSIZE2
Definition: jpeglib.h:51
const int jpeg_natural_order4[4 *4+16]
Definition: jutils.c:98
#define b
Definition: ke_i.h:79
JBLOCKROW JDIMENSION num_blocks
Definition: jpegint.h:415
__kernel_size_t size_t
Definition: linux.h:237
GLboolean GLboolean GLboolean b
Definition: glext.h:6204
int source_row
Definition: jpegint.h:412
const int jpeg_natural_order3[3 *3+16]
Definition: jutils.c:105
JBLOCKROW output_row
Definition: jpegint.h:415
jdiv_round_up(long a, long b)
Definition: jutils.c:124
JBLOCK FAR * JBLOCKROW
Definition: jpeglib.h:80
int JSAMPARRAY int int num_rows
Definition: jpegint.h:412
const int jpeg_natural_order5[5 *5+16]
Definition: jutils.c:89
int JSAMPARRAY int int JDIMENSION num_cols
Definition: jpegint.h:412
JCOEF FAR * JCOEFPTR
Definition: jpeglib.h:84
static const WCHAR L[]
Definition: oid.c:1250
JSAMPROW * JSAMPARRAY
Definition: jpeglib.h:76
const int jpeg_natural_order[DCTSIZE2+16]
Definition: jutils.c:54
#define GLOBAL(type)
Definition: jmorecfg.h:291
static const int jpeg_zigzag_order[8][8]
Definition: jdhuff.c:260
jcopy_block_row(JBLOCKROW input_row, JBLOCKROW output_row, JDIMENSION num_blocks)
Definition: jutils.c:211
unsigned int JDIMENSION
Definition: jmorecfg.h:229
GLenum target
Definition: glext.h:7315
GLboolean GLboolean GLboolean GLboolean a
Definition: glext.h:6204
jcopy_sample_rows(JSAMPARRAY input_array, int source_row, JSAMPARRAY output_array, int dest_row, int num_rows, JDIMENSION num_cols)
Definition: jutils.c:177
int JSAMPARRAY output_array
Definition: jpegint.h:412
const int jpeg_natural_order6[6 *6+16]
Definition: jutils.c:79
struct png_info_def *typedef unsigned char **typedef struct png_info_def *typedef struct png_info_def *typedef struct png_info_def *typedef unsigned char ** row
Definition: typeof.h:78