workbench/classes/datatypes/wav/bitpack_lsb.c

   1 /*
   2  *      wave.datatype
   3  *      (c) Fredrik Wikstrom
   4  */
   5
   6 #include <exec/types.h>
   7 #include <dos/dos.h>
   8
   9 #include "endian.h"
  10 #include "bitpack.h"
  11
  12 // LSb style functions:
  13
  14 extern const ULONG bp_mask[33];
  15
  16 ULONG bitpack_read1_lsb (BitPack_buffer *b) {
  17     ULONG ret=0;
  18     if (b->ptr[0]&(1 << b->endbit))
  19         ret=1;
  20     b->endbit++;
  21     if (b->endbit==8) {
  22         b->endbit=0;
  23         b->ptr++;
  24         b->endbyte++;
  25     }
  26     return (ret);
  27 }
  28
  29 ULONG bitpack_read_lsb (BitPack_buffer *b, LONG bits) {
  30     ULONG ret;
  31
  32     bits+=b->endbit;
  33
  34     ret=b->ptr[0]>>b->endbit;
  35     if (bits>8) {
  36         ret|=b->ptr[1]<<(8-b->endbit);
  37         if (bits>16) {
  38             ret|=b->ptr[2]<<(16-b->endbit);
  39             if (bits>24) {
  40                 ret|=b->ptr[3]<<(24-b->endbit);
  41                 if (bits>32) {
  42                     ret|=b->ptr[4]<<(32-b->endbit);
  43                 }
  44             }
  45         }
  46     }
  47     ret&=bp_mask[bits];
  48
  49     b->ptr+=(bits >> 3);
  50     b->endbyte+=(bits >> 3);
  51     b->endbit=bits&7;
  52
  53     return (ret);
  54 }
  55
  56 #if BP_WRITE_CMDS
  57
  58 void bitpack_write1_lsb (BitPack_buffer *b, ULONG val) {
  59         if (val & 1) {
  60                 b->ptr[0]|=(1 << b->endbit);
  61         } else {
  62                 b->ptr[0]&=~(1 << b->endbit);
  63         }
  64     b->endbit++;
  65     if (b->endbit==8) {
  66         b->endbit=0;
  67         b->ptr++;
  68         b->endbyte++;
  69     }
  70 }
  71
  72 void bitpack_write_lsb (BitPack_buffer *b, ULONG val, LONG bits) {
  73         val&=bp_mask[bits];
  74         bits+=b->endbit;
  75
  76         b->ptr[0]|=val<<b->endbit;
  77         if (bits>=8) {
  78                 b->ptr[1]=val>>(8-b->endbit);
  79                 if (bits>=16) {
  80                         b->ptr[2]=val>>(16-b->endbit);
  81                         if (bits>=32) {
  82                                 if (b->endbit)
  83                                         b->ptr[4]=val>>(32-b->endbit);
  84                                 else
  85                                         b->ptr[4]=0;
  86                         }
  87                 }
  88         }
  89
  90         b->endbyte+=(bits>>3);
  91         b->ptr+=(bits>>3);
  92         b->endbit=bits&7;
  93 }
  94
  95 #endif
  96
  97 #if BP_FAST_CMDS
  98
  99 void bitpack_iobits_lsb (ExtBitPack_buffer *b, LONG bits) {
 100 }
 101
 102 ULONG bitpack_fastread_lsb (ExtBitPack_buffer *b) {
 103 }
 104
 105 #if BP_WRITE_CMDS
 106
 107 void bitpack_fastwrite_lsb (ExtBitPack_buffer *b, ULONG val) {
 108 }
 109
 110 #endif
 111
 112 #endif