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718112a8fe
Currently none of these is being used, but eventually they will, once more code gets ported over. So it's better to have them right away and avoid editing the project file too much, only to revert that later.
227 lines
6.6 KiB
C
227 lines
6.6 KiB
C
/*
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* jutils.c
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*
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* Copyright (C) 1991-1996, Thomas G. Lane.
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* Modified 2009-2011 by Guido Vollbeding.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains tables and miscellaneous utility routines needed
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* for both compression and decompression.
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* Note we prefix all global names with "j" to minimize conflicts with
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* a surrounding application.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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/*
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* jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
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* of a DCT block read in natural order (left to right, top to bottom).
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*/
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#if 0 /* This table is not actually needed in v6a */
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const int jpeg_zigzag_order[DCTSIZE2] = {
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0, 1, 5, 6, 14, 15, 27, 28,
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2, 4, 7, 13, 16, 26, 29, 42,
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3, 8, 12, 17, 25, 30, 41, 43,
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9, 11, 18, 24, 31, 40, 44, 53,
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10, 19, 23, 32, 39, 45, 52, 54,
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20, 22, 33, 38, 46, 51, 55, 60,
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21, 34, 37, 47, 50, 56, 59, 61,
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35, 36, 48, 49, 57, 58, 62, 63
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};
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#endif
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/*
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* jpeg_natural_order[i] is the natural-order position of the i'th element
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* of zigzag order.
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*
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* When reading corrupted data, the Huffman decoders could attempt
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* to reference an entry beyond the end of this array (if the decoded
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* zero run length reaches past the end of the block). To prevent
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* wild stores without adding an inner-loop test, we put some extra
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* "63"s after the real entries. This will cause the extra coefficient
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* to be stored in location 63 of the block, not somewhere random.
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* The worst case would be a run-length of 15, which means we need 16
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* fake entries.
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*/
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const int jpeg_natural_order[DCTSIZE2+16] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 32, 25, 18, 11, 4, 5,
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12, 19, 26, 33, 40, 48, 41, 34,
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27, 20, 13, 6, 7, 14, 21, 28,
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35, 42, 49, 56, 57, 50, 43, 36,
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29, 22, 15, 23, 30, 37, 44, 51,
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58, 59, 52, 45, 38, 31, 39, 46,
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53, 60, 61, 54, 47, 55, 62, 63,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order7[7*7+16] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 32, 25, 18, 11, 4, 5,
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12, 19, 26, 33, 40, 48, 41, 34,
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27, 20, 13, 6, 14, 21, 28, 35,
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42, 49, 50, 43, 36, 29, 22, 30,
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37, 44, 51, 52, 45, 38, 46, 53,
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54,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order6[6*6+16] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 32, 25, 18, 11, 4, 5,
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12, 19, 26, 33, 40, 41, 34, 27,
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20, 13, 21, 28, 35, 42, 43, 36,
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29, 37, 44, 45,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order5[5*5+16] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 32, 25, 18, 11, 4, 12,
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19, 26, 33, 34, 27, 20, 28, 35,
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36,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order4[4*4+16] = {
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0, 1, 8, 16, 9, 2, 3, 10,
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17, 24, 25, 18, 11, 19, 26, 27,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order3[3*3+16] = {
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0, 1, 8, 16, 9, 2, 10, 17,
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18,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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const int jpeg_natural_order2[2*2+16] = {
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0, 1, 8, 9,
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63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
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63, 63, 63, 63, 63, 63, 63, 63
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};
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/*
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* Arithmetic utilities
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*/
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GLOBAL(long)
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jdiv_round_up (long a, long b)
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/* Compute a/b rounded up to next integer, ie, ceil(a/b) */
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/* Assumes a >= 0, b > 0 */
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{
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return (a + b - 1L) / b;
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}
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GLOBAL(long)
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jround_up (long a, long b)
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/* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
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/* Assumes a >= 0, b > 0 */
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{
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a += b - 1L;
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return a - (a % b);
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}
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/* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
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* and coefficient-block arrays. This won't work on 80x86 because the arrays
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* are FAR and we're assuming a small-pointer memory model. However, some
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* DOS compilers provide far-pointer versions of memcpy() and memset() even
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* in the small-model libraries. These will be used if USE_FMEM is defined.
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* Otherwise, the routines below do it the hard way. (The performance cost
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* is not all that great, because these routines aren't very heavily used.)
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*/
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#ifndef NEED_FAR_POINTERS /* normal case, same as regular macro */
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#define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
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#else /* 80x86 case, define if we can */
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#ifdef USE_FMEM
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#define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
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#else
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/* This function is for use by the FMEMZERO macro defined in jpegint.h.
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* Do not call this function directly, use the FMEMZERO macro instead.
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*/
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GLOBAL(void)
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jzero_far (void FAR * target, size_t bytestozero)
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/* Zero out a chunk of FAR memory. */
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/* This might be sample-array data, block-array data, or alloc_large data. */
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{
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register char FAR * ptr = (char FAR *) target;
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register size_t count;
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for (count = bytestozero; count > 0; count--) {
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*ptr++ = 0;
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}
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}
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#endif
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#endif
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GLOBAL(void)
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jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
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JSAMPARRAY output_array, int dest_row,
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int num_rows, JDIMENSION num_cols)
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/* Copy some rows of samples from one place to another.
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* num_rows rows are copied from input_array[source_row++]
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* to output_array[dest_row++]; these areas may overlap for duplication.
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* The source and destination arrays must be at least as wide as num_cols.
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*/
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{
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register JSAMPROW inptr, outptr;
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#ifdef FMEMCOPY
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register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
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#else
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register JDIMENSION count;
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#endif
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register int row;
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input_array += source_row;
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output_array += dest_row;
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for (row = num_rows; row > 0; row--) {
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inptr = *input_array++;
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outptr = *output_array++;
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#ifdef FMEMCOPY
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FMEMCOPY(outptr, inptr, count);
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#else
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for (count = num_cols; count > 0; count--)
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*outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */
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#endif
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}
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}
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GLOBAL(void)
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jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
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JDIMENSION num_blocks)
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/* Copy a row of coefficient blocks from one place to another. */
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{
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#ifdef FMEMCOPY
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FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
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#else
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register JCOEFPTR inptr, outptr;
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register long count;
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inptr = (JCOEFPTR) input_row;
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outptr = (JCOEFPTR) output_row;
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for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
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*outptr++ = *inptr++;
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}
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#endif
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}
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