blob: d74dc6b0977381c5f850be2417cdd18926d16315 [file] [log] [blame]
/**********************************************************************
* ISO MPEG Audio Subgroup Software Simulation Group (1996)
* ISO 13818-3 MPEG-2 Audio Encoder - Lower Sampling Frequency Extension
*
**********************************************************************/
/*
Revision History:
Date Programmer Comment
========== ========================= ===============================
1995/08/06 mc@fivebats.com created
1995/09/06 mc@fivebats.com modified to use formatBitstream
*/
#include <stdlib.h>
#include "lame.h"
#include "l3bitstream.h" /* the public interface */
#include "encoder.h"
#include "quantize.h"
#include "quantize-pvt.h"
#include "formatBitstream.h"
#include "tables.h"
#include <assert.h>
#include "l3bitstream-pvt.h"
static Bit_stream_struc *bs = NULL;
BF_FrameData *frameData = NULL;
BF_FrameResults *frameResults = NULL;
int PartHoldersInitialized = 0;
BF_PartHolder *headerPH;
BF_PartHolder *frameSIPH;
BF_PartHolder *channelSIPH[ MAX_CHANNELS ];
BF_PartHolder *spectrumSIPH[ MAX_GRANULES ][ MAX_CHANNELS ];
BF_PartHolder *scaleFactorsPH[ MAX_GRANULES ][ MAX_CHANNELS ];
BF_PartHolder *codedDataPH[ MAX_GRANULES ][ MAX_CHANNELS ];
BF_PartHolder *userSpectrumPH[ MAX_GRANULES ][ MAX_CHANNELS ];
BF_PartHolder *userFrameDataPH;
void putMyBits( u_int val, u_int len )
{
putbits( bs, val, len );
}
/*
III_format_bitstream()
This is called after a frame of audio has been quantized and coded.
It will write the encoded audio to the bitstream. Note that
from a layer3 encoder's perspective the bit stream is primarily
a series of main_data() blocks, with header and side information
inserted at the proper locations to maintain framing. (See Figure A.7
in the IS).
*/
void
III_format_bitstream( lame_global_flags *gfp,
int bitsPerFrame,
int l3_enc[2][2][576],
III_side_info_t *l3_side,
III_scalefac_t scalefac[2][2],
Bit_stream_struc *in_bs)
{
int gr, ch;
bs = in_bs;
if ( frameData == NULL )
{
frameData = calloc( 1,sizeof *frameData);
assert( frameData );
}
if ( frameResults == NULL )
{
frameResults = calloc( 1,sizeof *frameResults);
assert( frameResults );
}
if ( !PartHoldersInitialized )
{
headerPH = BF_newPartHolder( 14 );
frameSIPH = BF_newPartHolder( 12 );
for ( ch = 0; ch < MAX_CHANNELS; ch++ )
channelSIPH[ch] = BF_newPartHolder( 8 );
for ( gr = 0; gr < MAX_GRANULES; gr++ )
for ( ch = 0; ch < MAX_CHANNELS; ch++ )
{
spectrumSIPH[gr][ch] = BF_newPartHolder( 32 );
scaleFactorsPH[gr][ch] = BF_newPartHolder( 64 );
codedDataPH[gr][ch] = BF_newPartHolder( 576 );
userSpectrumPH[gr][ch] = BF_newPartHolder( 4 );
}
userFrameDataPH = BF_newPartHolder( 8 );
PartHoldersInitialized = 1;
}
encodeSideInfo( gfp,l3_side );
encodeMainData( gfp,l3_enc, l3_side, scalefac );
drain_into_ancillary_data( l3_side->resvDrain );
/*
Put frameData together for the call
to BitstreamFrame()
*/
frameData->frameLength = bitsPerFrame;
frameData->nGranules = gfp->mode_gr;
frameData->nChannels = gfp->stereo;
frameData->header = headerPH->part;
frameData->frameSI = frameSIPH->part;
for ( ch = 0; ch < gfp->stereo; ch++ )
frameData->channelSI[ch] = channelSIPH[ch]->part;
for ( gr = 0; gr < gfp->mode_gr; gr++ )
for ( ch = 0; ch < gfp->stereo; ch++ )
{
frameData->spectrumSI[gr][ch] = spectrumSIPH[gr][ch]->part;
frameData->scaleFactors[gr][ch] = scaleFactorsPH[gr][ch]->part;
frameData->codedData[gr][ch] = codedDataPH[gr][ch]->part;
frameData->userSpectrum[gr][ch] = userSpectrumPH[gr][ch]->part;
}
frameData->userFrameData = userFrameDataPH->part;
BF_BitstreamFrame( frameData, frameResults );
/* we set this here -- it will be tested in the next loops iteration */
l3_side->main_data_begin = frameResults->nextBackPtr;
}
void
III_FlushBitstream(void)
{
if (PartHoldersInitialized!=0)
BF_FlushBitstream( frameData, frameResults );
}
static unsigned slen1_tab[16] = { 0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4 };
static unsigned slen2_tab[16] = { 0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3 };
static void
encodeMainData( lame_global_flags *gfp,
int l3_enc[2][2][576],
III_side_info_t *si,
III_scalefac_t scalefac[2][2] )
{
int i, gr, ch, sfb, window;
for ( gr = 0; gr < gfp->mode_gr; gr++ )
for ( ch = 0; ch < gfp->stereo; ch++ )
scaleFactorsPH[gr][ch]->part->nrEntries = 0;
for ( gr = 0; gr < gfp->mode_gr; gr++ )
for ( ch = 0; ch < gfp->stereo; ch++ )
codedDataPH[gr][ch]->part->nrEntries = 0;
if ( gfp->version == 1 )
{ /* MPEG 1 */
for ( gr = 0; gr < 2; gr++ )
{
for ( ch = 0; ch < gfp->stereo; ch++ )
{
BF_PartHolder **pph = &scaleFactorsPH[gr][ch];
gr_info *gi = &(si->gr[gr].ch[ch].tt);
unsigned slen1 = slen1_tab[ gi->scalefac_compress ];
unsigned slen2 = slen2_tab[ gi->scalefac_compress ];
int *ix = &l3_enc[gr][ch][0];
if (gi->block_type == SHORT_TYPE)
{
#ifdef ALLOW_MIXED
if ( gi->mixed_block_flag )
{
for ( sfb = 0; sfb < 8; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen1 );
for ( sfb = 3; sfb < 6; sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen1 );
for ( sfb = 6; sfb < 12; sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen2 );
}
else
#endif
{
for ( sfb = 0; sfb < 6; sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen1 );
for ( sfb = 6; sfb < 12; sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen2 );
}
}
else
{
if ( (gr == 0) || (si->scfsi[ch][0] == 0) )
for ( sfb = 0; sfb < 6; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen1 );
if ( (gr == 0) || (si->scfsi[ch][1] == 0) )
for ( sfb = 6; sfb < 11; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen1 );
if ( (gr == 0) || (si->scfsi[ch][2] == 0) )
for ( sfb = 11; sfb < 16; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen2 );
if ( (gr == 0) || (si->scfsi[ch][3] == 0) )
for ( sfb = 16; sfb < 21; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen2 );
}
Huffmancodebits( &codedDataPH[gr][ch], ix, gi );
} /* for ch */
} /* for gr */
}
else
{ /* MPEG 2 */
gr = 0;
for ( ch = 0; ch < gfp->stereo; ch++ )
{
BF_PartHolder **pph = &scaleFactorsPH[gr][ch];
gr_info *gi = &(si->gr[gr].ch[ch].tt);
int *ix = &l3_enc[gr][ch][0];
int sfb_partition;
assert( gi->sfb_partition_table );
if (gi->block_type == SHORT_TYPE)
{
#ifdef ALLOW_MIXED
if ( gi->mixed_block_flag )
{
sfb_partition = 0;
for ( sfb = 0; sfb < 8; sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], gi->slen[sfb_partition] );
for ( sfb = 3, sfb_partition = 1; sfb_partition < 4; sfb_partition++ )
{
int sfbs = gi->sfb_partition_table[ sfb_partition ] / 3;
int slen = gi->slen[ sfb_partition ];
for ( i = 0; i < sfbs; i++, sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen );
}
}
else
#endif
{
for ( sfb = 0, sfb_partition = 0; sfb_partition < 4; sfb_partition++ )
{
int sfbs = gi->sfb_partition_table[ sfb_partition ] / 3;
int slen = gi->slen[ sfb_partition ];
for ( i = 0; i < sfbs; i++, sfb++ )
for ( window = 0; window < 3; window++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].s[sfb][window], slen );
}
}
}
else
{
for ( sfb = 0, sfb_partition = 0; sfb_partition < 4; sfb_partition++ )
{
int sfbs = gi->sfb_partition_table[ sfb_partition ];
int slen = gi->slen[ sfb_partition ];
for ( i = 0; i < sfbs; i++, sfb++ )
*pph = BF_addEntry( *pph, scalefac[gr][ch].l[sfb], slen );
}
}
Huffmancodebits( &codedDataPH[gr][ch], ix, gi );
} /* for ch */
}
} /* main_data */
static unsigned int crc = 0; /* (jo) current crc */
/* (jo) this wrapper function for BF_addEntry() updates also the crc */
static BF_PartHolder *CRC_BF_addEntry( BF_PartHolder *thePH, u_int value, u_int length )
{
u_int bit = 1 << length;
while((bit >>= 1)){
crc <<= 1;
if (!(crc & 0x10000) ^ !(value & bit))
crc ^= CRC16_POLYNOMIAL;
}
crc &= 0xffff;
return BF_addEntry(thePH, value, length);
}
static int encodeSideInfo( lame_global_flags *gfp,III_side_info_t *si )
{
int gr, ch, scfsi_band, region, window, bits_sent;
crc = 0xffff; /* (jo) init crc16 for error_protection */
headerPH->part->nrEntries = 0;
headerPH = BF_addEntry( headerPH, 0xfff, 12 );
headerPH = BF_addEntry( headerPH, gfp->version, 1 );
headerPH = BF_addEntry( headerPH, 1, 2 );
headerPH = BF_addEntry( headerPH, !gfp->error_protection, 1 );
/* (jo) from now on call the CRC_BF_addEntry() wrapper to update crc */
headerPH = CRC_BF_addEntry( headerPH, gfp->bitrate_index, 4 );
headerPH = CRC_BF_addEntry( headerPH, gfp->samplerate_index, 2 );
headerPH = CRC_BF_addEntry( headerPH, gfp->padding, 1 );
headerPH = CRC_BF_addEntry( headerPH, gfp->extension, 1 );
headerPH = CRC_BF_addEntry( headerPH, gfp->mode, 2 );
headerPH = CRC_BF_addEntry( headerPH, gfp->mode_ext, 2 );
headerPH = CRC_BF_addEntry( headerPH, gfp->copyright, 1 );
headerPH = CRC_BF_addEntry( headerPH, gfp->original, 1 );
headerPH = CRC_BF_addEntry( headerPH, gfp->emphasis, 2 );
bits_sent = 32;
/* (jo) see below for BF_addEntry( headerPH, crc, 16 ); */
frameSIPH->part->nrEntries = 0;
for (ch = 0; ch < gfp->stereo; ch++ )
channelSIPH[ch]->part->nrEntries = 0;
for ( gr = 0; gr < gfp->mode_gr; gr++ )
for ( ch = 0; ch < gfp->stereo; ch++ )
spectrumSIPH[gr][ch]->part->nrEntries = 0;
if ( gfp->version == 1 )
{ /* MPEG1 */
frameSIPH = CRC_BF_addEntry( frameSIPH, si->main_data_begin, 9 );
if ( gfp->stereo == 2 )
frameSIPH = CRC_BF_addEntry( frameSIPH, si->private_bits, 3 );
else
frameSIPH = CRC_BF_addEntry( frameSIPH, si->private_bits, 5 );
for ( ch = 0; ch < gfp->stereo; ch++ )
for ( scfsi_band = 0; scfsi_band < 4; scfsi_band++ )
{
BF_PartHolder **pph = &channelSIPH[ch];
*pph = CRC_BF_addEntry( *pph, si->scfsi[ch][scfsi_band], 1 );
}
for ( gr = 0; gr < 2; gr++ )
for ( ch = 0; ch < gfp->stereo; ch++ )
{
BF_PartHolder **pph = &spectrumSIPH[gr][ch];
gr_info *gi = &(si->gr[gr].ch[ch].tt);
*pph = CRC_BF_addEntry( *pph, gi->part2_3_length, 12 );
*pph = CRC_BF_addEntry( *pph, gi->big_values, 9 );
*pph = CRC_BF_addEntry( *pph, gi->global_gain, 8 );
*pph = CRC_BF_addEntry( *pph, gi->scalefac_compress, 4 );
*pph = CRC_BF_addEntry( *pph, gi->window_switching_flag, 1 );
if ( gi->window_switching_flag )
{
*pph = CRC_BF_addEntry( *pph, gi->block_type, 2 );
*pph = CRC_BF_addEntry( *pph, gi->mixed_block_flag, 1 );
for ( region = 0; region < 2; region++ )
*pph = CRC_BF_addEntry( *pph, gi->table_select[region], 5 );
for ( window = 0; window < 3; window++ )
*pph = CRC_BF_addEntry( *pph, gi->subblock_gain[window], 3 );
}
else
{
assert( gi->block_type == NORM_TYPE );
for ( region = 0; region < 3; region++ )
*pph = CRC_BF_addEntry( *pph, gi->table_select[region], 5 );
*pph = CRC_BF_addEntry( *pph, gi->region0_count, 4 );
*pph = CRC_BF_addEntry( *pph, gi->region1_count, 3 );
}
*pph = CRC_BF_addEntry( *pph, gi->preflag, 1 );
*pph = CRC_BF_addEntry( *pph, gi->scalefac_scale, 1 );
*pph = CRC_BF_addEntry( *pph, gi->count1table_select, 1 );
}
if ( gfp->stereo == 2 )
bits_sent += 256;
else
bits_sent += 136;
}
else
{ /* MPEG2 */
frameSIPH = CRC_BF_addEntry( frameSIPH, si->main_data_begin, 8 );
if ( gfp->stereo == 2 )
frameSIPH = CRC_BF_addEntry( frameSIPH, si->private_bits, 2 );
else
frameSIPH = CRC_BF_addEntry( frameSIPH, si->private_bits, 1 );
gr = 0;
for ( ch = 0; ch < gfp->stereo; ch++ )
{
BF_PartHolder **pph = &spectrumSIPH[gr][ch];
gr_info *gi = &(si->gr[gr].ch[ch].tt);
*pph = CRC_BF_addEntry( *pph, gi->part2_3_length, 12 );
*pph = CRC_BF_addEntry( *pph, gi->big_values, 9 );
*pph = CRC_BF_addEntry( *pph, gi->global_gain, 8 );
*pph = CRC_BF_addEntry( *pph, gi->scalefac_compress, 9 );
*pph = CRC_BF_addEntry( *pph, gi->window_switching_flag, 1 );
if ( gi->window_switching_flag )
{
*pph = CRC_BF_addEntry( *pph, gi->block_type, 2 );
*pph = CRC_BF_addEntry( *pph, gi->mixed_block_flag, 1 );
for ( region = 0; region < 2; region++ )
*pph = CRC_BF_addEntry( *pph, gi->table_select[region], 5 );
for ( window = 0; window < 3; window++ )
*pph = CRC_BF_addEntry( *pph, gi->subblock_gain[window], 3 );
}
else
{
for ( region = 0; region < 3; region++ )
*pph = CRC_BF_addEntry( *pph, gi->table_select[region], 5 );
*pph = CRC_BF_addEntry( *pph, gi->region0_count, 4 );
*pph = CRC_BF_addEntry( *pph, gi->region1_count, 3 );
}
*pph = CRC_BF_addEntry( *pph, gi->scalefac_scale, 1 );
*pph = CRC_BF_addEntry( *pph, gi->count1table_select, 1 );
}
if ( gfp->stereo == 2 )
bits_sent += 136;
else
bits_sent += 72;
}
if ( gfp->error_protection )
{ /* (jo) error_protection: add crc16 information to header */
headerPH = BF_addEntry( headerPH, crc, 16 );
bits_sent += 16;
}
return bits_sent;
}
/*
Some combinations of bitrate, Fs, and stereo make it impossible to stuff
out a frame using just main_data, due to the limited number of bits to
indicate main_data_length. In these situations, we put stuffing bits into
the ancillary data...
*/
static void
drain_into_ancillary_data( int lengthInBits )
{
/*
*/
int wordsToSend = lengthInBits / 32;
int remainingBits = lengthInBits % 32;
int i;
/*
userFrameDataPH->part->nrEntries set by call to write_ancillary_data()
*/
userFrameDataPH->part->nrEntries = 0;
for ( i = 0; i < wordsToSend; i++ )
userFrameDataPH = BF_addEntry( userFrameDataPH, 0, 32 );
if ( remainingBits )
userFrameDataPH = BF_addEntry( userFrameDataPH, 0, remainingBits );
}
/*
Note the discussion of huffmancodebits() on pages 28
and 29 of the IS, as well as the definitions of the side
information on pages 26 and 27.
*/
static void
Huffmancodebits( BF_PartHolder **pph, int *ix, gr_info *gi )
{
int L3_huffman_coder_count1( BF_PartHolder **pph, struct huffcodetab *h, int v, int w, int x, int y );
int region1Start;
int region2Start;
int i, bigvalues, count1End;
int v, w, x, y, bits, cbits, xbits, stuffingBits;
unsigned int code, ext;
#ifdef DEBUG
int bvbits, c1bits;
#endif
int bitsWritten = 0;
/* 1: Write the bigvalues */
bigvalues = gi->big_values * 2;
if ( bigvalues )
{
if ( !(gi->mixed_block_flag) && (gi->block_type == SHORT_TYPE) )
{ /* Three short blocks */
/*
Within each scalefactor band, data is given for successive
time windows, beginning with window 0 and ending with window 2.
Within each window, the quantized values are then arranged in
order of increasing frequency...
*/
int sfb, window, line, start, end;
I192_3 *ix_s;
ix_s = (I192_3 *) ix;
region1Start = 12;
region2Start = 576;
for ( sfb = 0; sfb < 13; sfb++ )
{
unsigned tableindex = 100;
start = scalefac_band.s[ sfb ];
end = scalefac_band.s[ sfb+1 ];
if ( start < region1Start )
tableindex = gi->table_select[ 0 ];
else
tableindex = gi->table_select[ 1 ];
assert( tableindex < 32 );
for ( window = 0; window < 3; window++ )
for ( line = start; line < end; line += 2 )
{
x = (*ix_s)[line][window];
y = (*ix_s)[line + 1][window];
bits = HuffmanCode( tableindex, x, y, &code, &ext, &cbits, &xbits );
*pph = BF_addEntry( *pph, code, cbits );
*pph = BF_addEntry( *pph, ext, xbits );
bitsWritten += bits;
}
}
}
else
#ifdef ALLOW_MIXED
if ( gi->mixed_block_flag && gi->block_type == SHORT_TYPE )
{ /* Mixed blocks long, short */
int sfb, window, line, start, end;
unsigned tableindex;
I192_3 *ix_s;
ix_s = (I192_3 *) ix;
/* Write the long block region */
tableindex = gi->table_select[0];
if ( tableindex )
for ( i = 0; i < 36; i += 2 )
{
x = ix[i];
y = ix[i + 1];
bits = HuffmanCode( tableindex, x, y, &code, &ext, &cbits, &xbits );
*pph = BF_addEntry( *pph, code, cbits );
*pph = BF_addEntry( *pph, ext, xbits );
bitsWritten += bits;
}
/* Write the short block region */
tableindex = gi->table_select[ 1 ];
assert( tableindex < 32 );
for ( sfb = 3; sfb < 13; sfb++ )
{
start = scalefac_band.s[ sfb ];
end = scalefac_band.s[ sfb+1 ];
for ( window = 0; window < 3; window++ )
for ( line = start; line < end; line += 2 )
{
x = (*ix_s)[line][window];
y = (*ix_s)[line + 1][window];
bits = HuffmanCode( tableindex, x, y, &code, &ext, &cbits, &xbits );
*pph = BF_addEntry( *pph, code, cbits );
*pph = BF_addEntry( *pph, ext, xbits );
bitsWritten += bits;
}
}
}
else
#endif
{ /* Long blocks */
unsigned scalefac_index = 100;
if ( gi->mixed_block_flag )
{
region1Start = 36;
region2Start = 576;
}
else
{
scalefac_index = gi->region0_count + 1;
assert( scalefac_index < 23 );
region1Start = scalefac_band.l[ scalefac_index ];
scalefac_index += gi->region1_count + 1;
assert( scalefac_index < 23 );
region2Start = scalefac_band.l[ scalefac_index ];
}
for ( i = 0; i < bigvalues; i += 2 )
{
unsigned tableindex = 100;
/* get table pointer */
if ( i < region1Start )
{
tableindex = gi->table_select[0];
}
else
if ( i < region2Start )
{
tableindex = gi->table_select[1];
}
else
{
tableindex = gi->table_select[2];
}
assert( tableindex < 32 );
/* get huffman code */
x = ix[i];
y = ix[i + 1];
if ( tableindex )
{
bits = HuffmanCode( tableindex, x, y, &code, &ext, &cbits, &xbits );
*pph = BF_addEntry( *pph, code, cbits );
*pph = BF_addEntry( *pph, ext, xbits );
bitsWritten += bits;
}
}
}
}
#ifdef DEBUG
bvbits = bitsWritten;
#endif
/* 2: Write count1 area */
assert( (gi->count1table_select < 2) );
count1End = bigvalues + (gi->count1 * 4);
assert( count1End <= 576 );
for ( i = bigvalues; i < count1End; i += 4 )
{
v = ix[i];
w = ix[i+1];
x = ix[i+2];
y = ix[i+3];
bitsWritten += L3_huffman_coder_count1( pph, &ht[gi->count1table_select + 32], v, w, x, y );
}
#ifdef DEBUG
c1bits = bitsWritten - bvbits;
#endif
if ( (stuffingBits = gi->part2_3_length - gi->part2_length - bitsWritten) )
{
int stuffingWords = stuffingBits / 32;
int remainingBits = stuffingBits % 32;
fprintf(stderr,"opps - adding stuffing bits = %i.\n",stuffingBits);
fprintf(stderr,"this should not happen...\n");
/*
Due to the nature of the Huffman code
tables, we will pad with ones
*/
while ( stuffingWords-- )
*pph = BF_addEntry( *pph, ~(u_int)0, 32 );
if ( remainingBits )
*pph = BF_addEntry( *pph, ~(u_int)0, remainingBits );
bitsWritten += stuffingBits;
}
assert( bitsWritten == (int)(gi->part2_3_length - gi->part2_length) );
#ifdef DEBUG
fprintf(stderr, "## %d Huffman bits written (%02d + %02d), part2_length = %d, part2_3_length = %d, %d stuffing ##\n",
bitsWritten, bvbits, c1bits, gi->part2_length, gi->part2_3_length, stuffingBits );
#endif
}
int
abs_and_sign( int *x )
{
if ( *x > 0 )
return 0;
*x *= -1;
return 1;
}
int
L3_huffman_coder_count1( BF_PartHolder **pph, struct huffcodetab *h, int v, int w, int x, int y )
{
HUFFBITS huffbits;
unsigned int signv, signw, signx, signy, p;
int len;
int totalBits = 0;
signv = abs_and_sign( &v );
signw = abs_and_sign( &w );
signx = abs_and_sign( &x );
signy = abs_and_sign( &y );
/* bug fix from Leonid A. Kulakov 9/1999:*/
p = (v << 3) + (w << 2) + (x << 1) + y;
huffbits = h->table[p];
len = h->hlen[ p ];
*pph = BF_addEntry(*pph, huffbits, len);
totalBits= 0;
#if 0
if ( v )
{
*pph = BF_addEntry( *pph, signv, 1 );
totalBits += 1;
}
if ( w )
{
*pph = BF_addEntry( *pph, signw, 1 );
totalBits += 1;
}
if ( x )
{
*pph = BF_addEntry( *pph, signx, 1 );
totalBits += 1;
}
if ( y )
{
*pph = BF_addEntry( *pph, signy, 1 );
totalBits += 1;
}
#endif
p=0;
if ( v ) {
p = signv;
++totalBits;
}
if ( w ){
p = 2*p + signw;
++totalBits;
}
if ( x ) {
p = 2*p + signx;
++totalBits;
}
if ( y ) {
p = 2*p + signy;
++totalBits;
}
*pph = BF_addEntry(*pph, p, totalBits);
return totalBits+len;
}
/*
Implements the pseudocode of page 98 of the IS
*/
int
HuffmanCode( int table_select, int x, int y, unsigned int *code, unsigned int *ext, int *cbits, int *xbits )
{
unsigned signx, signy, linbitsx, linbitsy, linbits, idx;
struct huffcodetab *h;
*cbits = 0;
*xbits = 0;
*code = 0;
*ext = 0;
if ( table_select == 0 )
return 0;
signx = abs_and_sign( &x );
signy = abs_and_sign( &y );
h = &(ht[table_select]);
if ( table_select > 15 )
{ /* ESC-table is used */
linbits = h->xlen;
linbitsx = linbitsy = 0;
if ( x > 14 )
{
linbitsx = x - 15;
assert( linbitsx <= h->linmax );
x = 15;
}
if ( y > 14 )
{
linbitsy = y - 15;
assert( linbitsy <= h->linmax );
y = 15;
}
idx = x * 16 + y;
*code = h->table[idx];
*cbits = h->hlen[ idx ];
if ( x > 14 )
{
*ext |= linbitsx;
*xbits += linbits;
}
if ( x != 0 )
{
*ext <<= 1;
*ext |= signx;
*xbits += 1;
}
if ( y > 14 )
{
*ext <<= linbits;
*ext |= linbitsy;
*xbits += linbits;
}
if ( y != 0 )
{
*ext <<= 1;
*ext |= signy;
*xbits += 1;
}
}
else
{ /* No ESC-words */
idx = x * 16 + y;
*code = h->table[idx];
*cbits += h->hlen[ idx ];
if ( x != 0 )
{
*code <<= 1;
*code |= signx;
*cbits += 1;
}
if ( y != 0 )
{
*code <<= 1;
*code |= signy;
*cbits += 1;
}
}
assert( *cbits <= 32 );
assert( *xbits <= 32 );
return *cbits + *xbits;
}