huff.c

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/*------------------------------------------------------------------------------

    File    :   HUFF.c

    Author  :   St閜hane TAVENARD

    $VER:   HUFF.c  0.4  (24/05/1999)

    (C) Copyright 1997-1999 St閜hane TAVENARD
        All Rights Reserved

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    #Rev|   Date   |                      Comment
    ----|----------|--------------------------------------------------------
    0   |17/03/1997| Initial revision                                     ST
    1   |31/03/1997| First aminet release                                 ST
    2   |07/06/1997| Added HUFF_fill_bytes                                ST
    3   |04/07/1997| Fix bug in HUFF_pos & HUFF_read_bits                 ST
    4   |24/05/1999| Added some const                                     ST

    ------------------------------------------------------------------------

    Huffman Codes handling

------------------------------------------------------------------------------*/

#include "defs.h"
#include "mpegaud.h"
#include "mpegtab.h"

void HUFF_close( HUFFMAN *h )
/*---------------------------
   Close the huffman stream
*/
{
   if( !h ) return;
   if( h->buffer ) free( h->buffer );
   free( h );

} /* HUFF_close */

int HUFF_reset( HUFFMAN *h )
/*--------------------------
   Reset an huffman stream
*/
{
   if( !h ) return -1;

   h->write_index = h->read_index = 0;
   h->bit_cache = h->cache_size = 0;
   h->nul_begin = 576; // begin of last null zone
   return 0;

} /* HUFF_reset */


HUFFMAN *HUFF_open( void )
/*------------------------
   Open an huffman stream
*/
{
   HUFFMAN *h;

   h = (HUFFMAN *)malloc( sizeof( HUFFMAN ) );
   if( !h ) return NULL;
   memset( h, 0, sizeof( HUFFMAN ) );
   h->buffer = malloc( HUFF_BUFFER_SIZE );
   if( !h ) {
      HUFF_close( h );
      return NULL;
   }
   memset( h->buffer, 0, HUFF_BUFFER_SIZE );
   h->buffer_size = HUFF_BUFFER_SIZE;

   return h;

} /* HUFF_open */

/* #2 Begin */

void HUFF_fill_bytes( HUFFMAN *h, unsigned int count, char *buffer )
/*-----------------------------------------------------------------
   Write bytes to huffman buffer
*/
{
   register unsigned int to_fill;

   while( count > 0 ) {
      to_fill = HUFF_BUFFER_SIZE - h->write_index;
      if( to_fill > count ) to_fill = count;
      memcpy( &h->buffer[ h->write_index ], buffer, to_fill );
      count -= to_fill;
      buffer += to_fill;
      h->write_index += to_fill;
      if( h->write_index >= HUFF_BUFFER_SIZE ) h->write_index = 0;
   }

} /* HUFF_fill_bytes */

/* #2 End */

int HUFF_set_start( HUFFMAN *h, int start_pos )
/*---------------------------------------------
   Set the start pos of the huffman buffer
   relative to the end of buffer (byte size).
   start_pos is used as a negative offset.
*/
{
   int size;

   size = h->write_index - h->read_index + (h->cache_size>>3);
   if( size < 0 ) size += HUFF_BUFFER_SIZE;
   if( size < start_pos ) {
//printf( "* remain size=%d start=%d\n", size, start_pos );
      return -1; // Not enough data
   }

   h->read_index = (h->write_index - start_pos) & (HUFF_BUFFER_SIZE-1);
   h->cache_size = 0; // Flush cache
   return 0;

} /* HUFF_set_start */


#define FILL_CACHE( h ) { \
   h->bit_cache = ((UINT32)h->buffer[ h->read_index & (HUFF_BUFFER_SIZE-1) ])<<24 |\
                  ((UINT32)h->buffer[ (h->read_index + 1) & (HUFF_BUFFER_SIZE-1) ])<<16 |\
                  ((UINT32)h->buffer[ (h->read_index + 2) & (HUFF_BUFFER_SIZE-1) ])<<8 |\
                  ((UINT32)h->buffer[ (h->read_index + 3) & (HUFF_BUFFER_SIZE-1) ]);\
                                  h->read_index = (h->read_index + 4) & (HUFF_BUFFER_SIZE-1);\
}


int HUFF_seek( HUFFMAN *h, int seek_pos )
/*---------------------------------------------
   Seek to a bit pos in the huffman buffer
   (absolute pos)
*/
{
   int advance;

   h->read_index = (seek_pos >> 3) & (HUFF_BUFFER_SIZE-1);
   advance = seek_pos & 7;
   FILL_CACHE( h );
   h->cache_size = 32;
   // Discard some bits if not aligned
   if( advance ) HUFF_read_bits( h, advance );
   return 0;

} /* HUFF_seek */


unsigned long HUFF_read_bit_cache( HUFFMAN *h )
/*--------------------------------------------
   Update the bit cache and return next bit
*/
{
   register unsigned long bits;

   FILL_CACHE( h );

   h->cache_size = 31;

   bits = (h->bit_cache & 0x80000000)?1:0;
   h->bit_cache <<= 1;

   return bits;
}

unsigned long HUFF_read_bits_cache( HUFFMAN *h, unsigned int count )
/*-----------------------------------------------------------------
   Update the bit cache and return next bits
*/
{
   register unsigned long bits;

   if( h->cache_size > 0 ) { // #3
      bits = h->bit_cache >> (32 - count);
      count -= h->cache_size;
   }
   else bits = 0;

   FILL_CACHE( h );
   h->cache_size = 32 - count;

   bits |= h->bit_cache >> (32 - count);
   h->bit_cache <<= count;

   return bits;
}


/* Huffman tables */

//static const UINT32 h0[1]={0x0};
static const UINT32 h1[4]={0x311, 0x20000301, 0x40000210, 0x80000100};
static const UINT32 h2[9]={0x622, 0x4000602, 0x8000512, 0x10000521, 0x18000520, 0x20000311, 0x40000301, 0x60000310,
 0x80000100};
static const UINT32 h3[9]={ 0x622, 0x4000602, 0x8000512, 0x10000521, 0x18000520, 0x20000310, 0x40000211, 0x80000201,
 0xc0000200};
static const UINT32 h5[16]={0x833, 0x1000823, 0x2000732, 0x4000631, 0x8000713, 0xa000703, 0xc000730, 0xe000722,
 0x10000612, 0x14000621, 0x18000602, 0x1c000620, 0x20000311, 0x40000301, 0x60000310, 0x80000100};
static const UINT32 h6[16]={0x733, 0x2000703, 0x4000623, 0x8000632, 0xc000630, 0x10000513, 0x18000531, 0x20000522,
 0x28000502, 0x30000412, 0x40000421, 0x50000420, 0x60000301, 0x80000211, 0xc0000310, 0xe0000300};
static const UINT32 h7[36]={ 0xa55, 0x400a45, 0x800a54, 0xc00a53, 0x1000935, 0x1800944, 0x2000925, 0x2800952,
 0x3000815, 0x4000851, 0x5000905, 0x5800934, 0x6000850, 0x7000943, 0x7800933, 0x8000824,
 0x9000842, 0xa000714, 0xc000741, 0xe000740, 0x10000804, 0x11000823, 0x12000832, 0x13000803,
 0x14000713, 0x16000731, 0x18000730, 0x1a000722, 0x1c000612, 0x20000521, 0x28000602, 0x2c000620,
 0x30000411, 0x40000301, 0x60000310, 0x80000100};
static const UINT32 h8[36]={0xb55, 0x200b54, 0x400a45, 0x800953, 0x1000a35, 0x1400a44, 0x1800925, 0x2000952,
 0x2800905, 0x3000815, 0x4000851, 0x5000934, 0x5800943, 0x6000950, 0x6800933, 0x7000824,
 0x8000842, 0x9000814, 0xa000741, 0xc000804, 0xd000840, 0xe000823, 0xf000832, 0x10000813,
 0x11000831, 0x12000803, 0x13000830, 0x14000622, 0x18000602, 0x1c000620, 0x20000412, 0x30000421,
 0x40000211, 0x80000301, 0xa0000310, 0xc0000200};
static const UINT32 h9[36]={
 0x00000955, 0x00800945, 0x01000835, 0x02000853, 0x03000954, 0x03800905, 0x04000844, 0x05000825,
 0x06000852, 0x07000815, 0x08000751, 0x0a000734, 0x0c000743, 0x0e000850, 0x0f000804, 0x10000724,
 0x12000742, 0x14000733, 0x16000740, 0x18000614, 0x1c000641, 0x20000623, 0x24000632, 0x28000513,
 0x30000531, 0x38000603, 0x3c000630, 0x40000522, 0x48000502, 0x50000412, 0x60000421, 0x70000420,
 0x80000311, 0xa0000301, 0xc0000310, 0xe0000300};
static const UINT32 h10[64]={ 0xb77, 0x200b67, 0x400b76, 0x600b57, 0x800b75, 0xa00b66, 0xc00a47, 0x1000a74,
 0x1400a56, 0x1800a65, 0x1c00a37, 0x2000a73, 0x2400a46, 0x2800b55, 0x2a00b54, 0x2c00a63,
 0x3000927, 0x3800972, 0x4000a64, 0x4400a07, 0x4800970, 0x5000962, 0x5800a45, 0x5c00a35,
 0x6000906, 0x6800a53, 0x6c00a44, 0x7000817, 0x8000871, 0x9000936, 0x9800926, 0xa000a25,
 0xa400a52, 0xa800915, 0xb000951, 0xb800a34, 0xbc00a43, 0xc000816, 0xd000861, 0xe000860,
 0xf000905, 0xf800950, 0x10000924, 0x10800942, 0x11000933, 0x11800904, 0x12000814, 0x13000841,
 0x14000840, 0x15000823, 0x16000832, 0x17000803, 0x18000713, 0x1a000731, 0x1c000730, 0x1e000722,
 0x20000612, 0x24000621, 0x28000602, 0x2c000620, 0x30000411, 0x40000301, 0x60000310, 0x80000100};
static const UINT32 h11[64]={ 0xa77, 0x400a67, 0x800a76, 0xc00a75, 0x1000a66, 0x1400a47, 0x1800a74, 0x1c00b57,