LCOV - code coverage report
Current view: directory - media/libjpeg - jutils.c (source / functions) Found Hit Coverage
Test: app.info Lines: 20 17 85.0 %
Date: 2012-06-02 Functions: 5 4 80.0 %

       1                 : /*
       2                 :  * jutils.c
       3                 :  *
       4                 :  * Copyright (C) 1991-1996, Thomas G. Lane.
       5                 :  * This file is part of the Independent JPEG Group's software.
       6                 :  * For conditions of distribution and use, see the accompanying README file.
       7                 :  *
       8                 :  * This file contains tables and miscellaneous utility routines needed
       9                 :  * for both compression and decompression.
      10                 :  * Note we prefix all global names with "j" to minimize conflicts with
      11                 :  * a surrounding application.
      12                 :  */
      13                 : 
      14                 : #define JPEG_INTERNALS
      15                 : #include "jinclude.h"
      16                 : #include "jpeglib.h"
      17                 : 
      18                 : 
      19                 : /*
      20                 :  * jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
      21                 :  * of a DCT block read in natural order (left to right, top to bottom).
      22                 :  */
      23                 : 
      24                 : #if 0                           /* This table is not actually needed in v6a */
      25                 : 
      26                 : const int jpeg_zigzag_order[DCTSIZE2] = {
      27                 :    0,  1,  5,  6, 14, 15, 27, 28,
      28                 :    2,  4,  7, 13, 16, 26, 29, 42,
      29                 :    3,  8, 12, 17, 25, 30, 41, 43,
      30                 :    9, 11, 18, 24, 31, 40, 44, 53,
      31                 :   10, 19, 23, 32, 39, 45, 52, 54,
      32                 :   20, 22, 33, 38, 46, 51, 55, 60,
      33                 :   21, 34, 37, 47, 50, 56, 59, 61,
      34                 :   35, 36, 48, 49, 57, 58, 62, 63
      35                 : };
      36                 : 
      37                 : #endif
      38                 : 
      39                 : /*
      40                 :  * jpeg_natural_order[i] is the natural-order position of the i'th element
      41                 :  * of zigzag order.
      42                 :  *
      43                 :  * When reading corrupted data, the Huffman decoders could attempt
      44                 :  * to reference an entry beyond the end of this array (if the decoded
      45                 :  * zero run length reaches past the end of the block).  To prevent
      46                 :  * wild stores without adding an inner-loop test, we put some extra
      47                 :  * "63"s after the real entries.  This will cause the extra coefficient
      48                 :  * to be stored in location 63 of the block, not somewhere random.
      49                 :  * The worst case would be a run-length of 15, which means we need 16
      50                 :  * fake entries.
      51                 :  */
      52                 : 
      53                 : const int jpeg_natural_order[DCTSIZE2+16] = {
      54                 :   0,  1,  8, 16,  9,  2,  3, 10,
      55                 :  17, 24, 32, 25, 18, 11,  4,  5,
      56                 :  12, 19, 26, 33, 40, 48, 41, 34,
      57                 :  27, 20, 13,  6,  7, 14, 21, 28,
      58                 :  35, 42, 49, 56, 57, 50, 43, 36,
      59                 :  29, 22, 15, 23, 30, 37, 44, 51,
      60                 :  58, 59, 52, 45, 38, 31, 39, 46,
      61                 :  53, 60, 61, 54, 47, 55, 62, 63,
      62                 :  63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
      63                 :  63, 63, 63, 63, 63, 63, 63, 63
      64                 : };
      65                 : 
      66                 : 
      67                 : /*
      68                 :  * Arithmetic utilities
      69                 :  */
      70                 : 
      71                 : GLOBAL(long)
      72             180 : jdiv_round_up (long a, long b)
      73                 : /* Compute a/b rounded up to next integer, ie, ceil(a/b) */
      74                 : /* Assumes a >= 0, b > 0 */
      75                 : {
      76             180 :   return (a + b - 1L) / b;
      77                 : }
      78                 : 
      79                 : 
      80                 : GLOBAL(long)
      81              10 : jround_up (long a, long b)
      82                 : /* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
      83                 : /* Assumes a >= 0, b > 0 */
      84                 : {
      85              10 :   a += b - 1L;
      86              10 :   return a - (a % b);
      87                 : }
      88                 : 
      89                 : 
      90                 : /* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
      91                 :  * and coefficient-block arrays.  This won't work on 80x86 because the arrays
      92                 :  * are FAR and we're assuming a small-pointer memory model.  However, some
      93                 :  * DOS compilers provide far-pointer versions of memcpy() and memset() even
      94                 :  * in the small-model libraries.  These will be used if USE_FMEM is defined.
      95                 :  * Otherwise, the routines below do it the hard way.  (The performance cost
      96                 :  * is not all that great, because these routines aren't very heavily used.)
      97                 :  */
      98                 : 
      99                 : #ifndef NEED_FAR_POINTERS       /* normal case, same as regular macros */
     100                 : #define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
     101                 : #define FMEMZERO(target,size)   MEMZERO(target,size)
     102                 : #else                           /* 80x86 case, define if we can */
     103                 : #ifdef USE_FMEM
     104                 : #define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
     105                 : #define FMEMZERO(target,size)   _fmemset((void FAR *)(target), 0, (size_t)(size))
     106                 : #endif
     107                 : #endif
     108                 : 
     109                 : 
     110                 : GLOBAL(void)
     111             432 : jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
     112                 :                    JSAMPARRAY output_array, int dest_row,
     113                 :                    int num_rows, JDIMENSION num_cols)
     114                 : /* Copy some rows of samples from one place to another.
     115                 :  * num_rows rows are copied from input_array[source_row++]
     116                 :  * to output_array[dest_row++]; these areas may overlap for duplication.
     117                 :  * The source and destination arrays must be at least as wide as num_cols.
     118                 :  */
     119                 : {
     120                 :   register JSAMPROW inptr, outptr;
     121                 : #ifdef FMEMCOPY
     122             432 :   register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
     123                 : #else
     124                 :   register JDIMENSION count;
     125                 : #endif
     126                 :   register int row;
     127                 : 
     128             432 :   input_array += source_row;
     129             432 :   output_array += dest_row;
     130                 : 
     131             864 :   for (row = num_rows; row > 0; row--) {
     132             432 :     inptr = *input_array++;
     133             432 :     outptr = *output_array++;
     134                 : #ifdef FMEMCOPY
     135             432 :     FMEMCOPY(outptr, inptr, count);
     136                 : #else
     137                 :     for (count = num_cols; count > 0; count--)
     138                 :       *outptr++ = *inptr++;     /* needn't bother with GETJSAMPLE() here */
     139                 : #endif
     140                 :   }
     141             432 : }
     142                 : 
     143                 : 
     144                 : GLOBAL(void)
     145               0 : jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
     146                 :                  JDIMENSION num_blocks)
     147                 : /* Copy a row of coefficient blocks from one place to another. */
     148                 : {
     149                 : #ifdef FMEMCOPY
     150               0 :   FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
     151                 : #else
     152                 :   register JCOEFPTR inptr, outptr;
     153                 :   register long count;
     154                 : 
     155                 :   inptr = (JCOEFPTR) input_row;
     156                 :   outptr = (JCOEFPTR) output_row;
     157                 :   for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
     158                 :     *outptr++ = *inptr++;
     159                 :   }
     160                 : #endif
     161               0 : }
     162                 : 
     163                 : 
     164                 : GLOBAL(void)
     165              31 : jzero_far (void FAR * target, size_t bytestozero)
     166                 : /* Zero out a chunk of FAR memory. */
     167                 : /* This might be sample-array data, block-array data, or alloc_large data. */
     168                 : {
     169                 : #ifdef FMEMZERO
     170              31 :   FMEMZERO(target, bytestozero);
     171                 : #else
     172                 :   register char FAR * ptr = (char FAR *) target;
     173                 :   register size_t count;
     174                 : 
     175                 :   for (count = bytestozero; count > 0; count--) {
     176                 :     *ptr++ = 0;
     177                 :   }
     178                 : #endif
     179              31 : }

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