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Diffstat (limited to 'ioq3-r437/src/jpeg-6/jutils.c')
| -rw-r--r-- | ioq3-r437/src/jpeg-6/jutils.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/ioq3-r437/src/jpeg-6/jutils.c b/ioq3-r437/src/jpeg-6/jutils.c new file mode 100644 index 00000000..4ba2a543 --- /dev/null +++ b/ioq3-r437/src/jpeg-6/jutils.c @@ -0,0 +1,175 @@ +/* + * jutils.c + * + * Copyright (C) 1991-1995, 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). + */ + +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 +}; + +/* + * 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 +} |