workbench/classes/datatypes/wav/bitpack_msb.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 // MSb style BitPack functions:
  13
  14 extern const ULONG bp_mask[33];
  15
  16 ULONG bitpack_read1_msb (BitPack_buffer *b) {
  17     ULONG ret=0;
  18     if (b->ptr[0]&(0x80 >> 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_msb (BitPack_buffer *b, LONG bits) {
  30     ULONG ret;
  31
  32     bits += b->endbit;
  33
  34     ret=b->ptr[0]<<(24+b->endbit);
  35     if (bits>8) {
  36         ret|=b->ptr[1]<<(16+b->endbit);
  37         if (bits>16) {
  38             ret|=b->ptr[2]<<(8+b->endbit);
  39             if (bits>24) {
  40                 ret|=b->ptr[3]<<(b->endbit);
  41                 if (bits>32) {
  42                     ret|=b->ptr[4]>>(8-b->endbit);
  43                 }
  44             }
  45         }
  46     }
  47     ret>>=(32-bits);
  48     ret&=bp_mask[bits];
  49
  50     b->ptr+=(bits >> 3);
  51     b->endbyte+=(bits >> 3);
  52     b->endbit=bits&7;
  53
  54     return (ret);
  55 }
  56
  57 #if BP_WRITE_CMDS
  58
  59 void bitpack_write1_msb (BitPack_buffer *b, ULONG val) {
  60         if (val & 1) {
  61                 b->ptr[0]|=(0x80 >> b->endbit);
  62         } else {
  63                 b->ptr[0]&=~(0x80 >> b->endbit);
  64         }
  65     b->endbit++;
  66     if (b->endbit==8) {
  67         b->endbit=0;
  68         b->ptr++;
  69         b->endbyte++;
  70     }
  71 }
  72
  73 void bitpack_write_msb (BitPack_buffer *b, ULONG val, LONG bits) {
  74         val&=bp_mask[bits];
  75         val<<=(32-bits);
  76         bits+=b->endbit;
  77
  78         b->ptr[0]|=val>>(24+b->endbit);
  79         if (bits>=8) {
  80                 b->ptr[1]=val>>(16+b->endbit);
  81                 if (bits>=16) {
  82                         b->ptr[2]=val>>(8+b->endbit);
  83                         if (bits>=32) {
  84                                 if (b->endbit)
  85                                         b->ptr[4]=val>>(b->endbit);
  86                                 else
  87                                         b->ptr[4]=0;
  88                         }
  89                 }
  90         }
  91
  92         b->endbyte+=(bits>>3);
  93         b->ptr+=(bits>>3);
  94         b->endbit=bits&7;
  95 }
  96
  97 #endif
  98
  99 #if BP_FAST_CMDS
 100
 101 void bitpack_iobits_msb (ExtBitPack_buffer *b, LONG bits) {
 102 }
 103
 104 ULONG bitpack_fastread_msb (ExtBitPack_buffer *b) {
 105 }
 106
 107 #if BP_WRITE_CMDS
 108
 109 void bitpack_fastwrite_msb (ExtBitPack_buffer *b, ULONG val) {
 110 }
 111
 112 #endif
 113
 114 #endif