#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* jutils.c | |
* | |
* Copyright (C) 1991-1996, Thomas G. Lane. | |
* 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 | |
}; | |
/* | |
* 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 macros */ | |
#define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size) | |
#define FMEMZERO(target,size) MEMZERO(target,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)) | |
#define FMEMZERO(target,size) _fmemset((void FAR *)(target), 0, (size_t)(size)) | |
#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 | |
} | |
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. */ | |
{ | |
#ifdef FMEMZERO | |
FMEMZERO(target, bytestozero); | |
#else | |
register char FAR * ptr = (char FAR *) target; | |
register size_t count; | |
for (count = bytestozero; count > 0; count--) { | |
*ptr++ = 0; | |
} | |
#endif | |
} | |
#endif //_FX_JPEG_TURBO_ |