1#if !defined(_FX_JPEG_TURBO_)
2/*
3 * jutils.c
4 *
5 * Copyright (C) 1991-1996, Thomas G. Lane.
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
27const 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
54const 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
68/*
69 * Arithmetic utilities
70 */
71
72GLOBAL(long)
73jdiv_round_up (long a, long b)
74/* Compute a/b rounded up to next integer, ie, ceil(a/b) */
75/* Assumes a >= 0, b > 0 */
76{
77  return (a + b - 1L) / b;
78}
79
80
81GLOBAL(long)
82jround_up (long a, long b)
83/* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
84/* Assumes a >= 0, b > 0 */
85{
86  a += b - 1L;
87  return a - (a % b);
88}
89
90
91/* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
92 * and coefficient-block arrays.  This won't work on 80x86 because the arrays
93 * are FAR and we're assuming a small-pointer memory model.  However, some
94 * DOS compilers provide far-pointer versions of memcpy() and memset() even
95 * in the small-model libraries.  These will be used if USE_FMEM is defined.
96 * Otherwise, the routines below do it the hard way.  (The performance cost
97 * is not all that great, because these routines aren't very heavily used.)
98 */
99
100#ifndef NEED_FAR_POINTERS	/* normal case, same as regular macros */
101#define FMEMCOPY(dest,src,size)	MEMCOPY(dest,src,size)
102#define FMEMZERO(target,size)	MEMZERO(target,size)
103#else				/* 80x86 case, define if we can */
104#ifdef USE_FMEM
105#define FMEMCOPY(dest,src,size)	_fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
106#define FMEMZERO(target,size)	_fmemset((void FAR *)(target), 0, (size_t)(size))
107#endif
108#endif
109
110
111GLOBAL(void)
112jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
113		   JSAMPARRAY output_array, int dest_row,
114		   int num_rows, JDIMENSION num_cols)
115/* Copy some rows of samples from one place to another.
116 * num_rows rows are copied from input_array[source_row++]
117 * to output_array[dest_row++]; these areas may overlap for duplication.
118 * The source and destination arrays must be at least as wide as num_cols.
119 */
120{
121  register JSAMPROW inptr, outptr;
122#ifdef FMEMCOPY
123  register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
124#else
125  register JDIMENSION count;
126#endif
127  register int row;
128
129  input_array += source_row;
130  output_array += dest_row;
131
132  for (row = num_rows; row > 0; row--) {
133    inptr = *input_array++;
134    outptr = *output_array++;
135#ifdef FMEMCOPY
136    FMEMCOPY(outptr, inptr, count);
137#else
138    for (count = num_cols; count > 0; count--)
139      *outptr++ = *inptr++;	/* needn't bother with GETJSAMPLE() here */
140#endif
141  }
142}
143
144
145GLOBAL(void)
146jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
147		 JDIMENSION num_blocks)
148/* Copy a row of coefficient blocks from one place to another. */
149{
150#ifdef FMEMCOPY
151  FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
152#else
153  register JCOEFPTR inptr, outptr;
154  register long count;
155
156  inptr = (JCOEFPTR) input_row;
157  outptr = (JCOEFPTR) output_row;
158  for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
159    *outptr++ = *inptr++;
160  }
161#endif
162}
163
164
165GLOBAL(void)
166jzero_far (void FAR * target, size_t bytestozero)
167/* Zero out a chunk of FAR memory. */
168/* This might be sample-array data, block-array data, or alloc_large data. */
169{
170#ifdef FMEMZERO
171  FMEMZERO(target, bytestozero);
172#else
173  register char FAR * ptr = (char FAR *) target;
174  register size_t count;
175
176  for (count = bytestozero; count > 0; count--) {
177    *ptr++ = 0;
178  }
179#endif
180}
181
182#endif //_FX_JPEG_TURBO_
183