| /* |
| * jutils.c |
| * |
| * Copyright (C) 1991, 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 miscellaneous utility routines needed for both |
| * compression and decompression. |
| * Note we prefix all global names with "j" to minimize conflicts with |
| * a surrounding application. |
| */ |
| |
| #include "jinclude.h" |
| |
| |
| GLOBAL long |
| jround_up (long a, long b) |
| /* Compute a rounded up to next multiple of b; a >= 0, b > 0 */ |
| { |
| a += b-1; |
| return a - (a % b); |
| } |
| |
| |
| GLOBAL void |
| jcopy_sample_rows (JSAMPARRAY input_array, int source_row, |
| JSAMPARRAY output_array, int dest_row, |
| int num_rows, long 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 should not overlap. |
| * The source and destination arrays must be at least as wide as num_cols. |
| */ |
| { |
| /* On normal machines we can use memcpy(). This won't work on 80x86 because |
| * the sample arrays are FAR and we're assuming a small-pointer memory model. |
| */ |
| register JSAMPROW inptr, outptr; |
| #ifdef NEED_FAR_POINTERS |
| register long count; |
| #else |
| register size_t count = num_cols * SIZEOF(JSAMPLE); |
| #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 NEED_FAR_POINTERS |
| for (count = num_cols; count > 0; count--) |
| *outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */ |
| #else |
| memcpy((void *) outptr, (void *) inptr, count); |
| #endif |
| } |
| } |
| |
| |
| GLOBAL void |
| jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row, long num_blocks) |
| /* Copy a row of coefficient blocks from one place to another. */ |
| { |
| /* On normal machines we can use memcpy(). This won't work on 80x86 because |
| * the block arrays are FAR and we're assuming a small-pointer memory model. |
| */ |
| #ifdef NEED_FAR_POINTERS |
| register JCOEFPTR inptr, outptr; |
| register int i; |
| register long count; |
| |
| for (count = num_blocks; count > 0; count--) { |
| inptr = *input_row++; |
| outptr = *output_row++; |
| for (i = DCTSIZE2; i > 0; i--) |
| *outptr++ = *inptr++; |
| } |
| #else |
| memcpy((void *) output_row, (void *) input_row, |
| (size_t) (num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)))); |
| #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_medium data. */ |
| { |
| /* On normal machines we can use MEMZERO(). This won't work on 80x86 |
| * because we're assuming a small-pointer memory model. |
| */ |
| #ifdef NEED_FAR_POINTERS |
| register char FAR * ptr = (char FAR *) target; |
| register size_t count; |
| |
| for (count = bytestozero; count > 0; count--) { |
| *ptr++ = 0; |
| } |
| #else |
| MEMZERO((void *) target, bytestozero); |
| #endif |
| } |