ref: 6f06d3436dafe1f697eb86ace9cbfd645f0d2439
dir: /silk/silk_code_signs.c/
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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modification, (subject to the limitations in the disclaimer below)
are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
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documentation and/or other materials provided with the distribution.
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this software without specific prior written permission.
NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/
#include "silk_main.h"
//#define SKP_enc_map(a) ((a) > 0 ? 1 : 0)
//#define SKP_dec_map(a) ((a) > 0 ? 1 : -1)
/* shifting avoids if-statement */
#define SKP_enc_map(a) ( SKP_RSHIFT( (a), 15 ) + 1 )
#define SKP_dec_map(a) ( SKP_LSHIFT( (a), 1 ) - 1 )
/* Encodes signs of excitation */
void silk_encode_signs(
ec_enc *psRangeEnc, /* I/O Compressor data structure */
const SKP_int8 pulses[], /* I pulse signal */
SKP_int length, /* I length of input */
const SKP_int signalType, /* I Signal type */
const SKP_int quantOffsetType, /* I Quantization offset type */
const SKP_int sum_pulses[ MAX_NB_SHELL_BLOCKS ] /* I Sum of absolute pulses per block */
)
{
SKP_int i, j, p;
SKP_uint8 icdf[ 2 ];
const SKP_int8 *q_ptr;
const SKP_uint8 *icdf_ptr;
icdf[ 1 ] = 0;
q_ptr = pulses;
i = SKP_SMULBB( 6, SKP_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
icdf_ptr = &silk_sign_iCDF[ i ];
length = SKP_RSHIFT( length + SHELL_CODEC_FRAME_LENGTH/2, LOG2_SHELL_CODEC_FRAME_LENGTH );
for( i = 0; i < length; i++ ) {
p = sum_pulses[ i ];
if( p > 0 ) {
icdf[ 0 ] = icdf_ptr[ SKP_min( p - 1, 5 ) ];
for( j = 0; j < SHELL_CODEC_FRAME_LENGTH; j++ ) {
if( q_ptr[ j ] != 0 ) {
ec_enc_icdf( psRangeEnc, SKP_enc_map( q_ptr[ j ]), icdf, 8 );
}
}
}
q_ptr += SHELL_CODEC_FRAME_LENGTH;
}
}
/* Decodes signs of excitation */
void silk_decode_signs(
ec_dec *psRangeDec, /* I/O Compressor data structure */
SKP_int pulses[], /* I/O pulse signal */
SKP_int length, /* I length of input */
const SKP_int signalType, /* I Signal type */
const SKP_int quantOffsetType, /* I Quantization offset type */
const SKP_int sum_pulses[ MAX_NB_SHELL_BLOCKS ] /* I Sum of absolute pulses per block */
)
{
SKP_int i, j, p;
SKP_uint8 icdf[ 2 ];
SKP_int *q_ptr;
const SKP_uint8 *icdf_ptr;
icdf[ 1 ] = 0;
q_ptr = pulses;
i = SKP_SMULBB( 6, SKP_ADD_LSHIFT( quantOffsetType, signalType, 1 ) );
icdf_ptr = &silk_sign_iCDF[ i ];
length = SKP_RSHIFT( length + SHELL_CODEC_FRAME_LENGTH/2, LOG2_SHELL_CODEC_FRAME_LENGTH );
for( i = 0; i < length; i++ ) {
p = sum_pulses[ i ];
if( p > 0 ) {
icdf[ 0 ] = icdf_ptr[ SKP_min( p - 1, 5 ) ];
for( j = 0; j < SHELL_CODEC_FRAME_LENGTH; j++ ) {
if( q_ptr[ j ] > 0 ) {
/* attach sign */
#if 0
/* conditional implementation */
if( ec_dec_icdf( psRangeDec, icdf, 8 ) == 0 ) {
q_ptr[ j ] = -q_ptr[ j ];
}
#else
/* implementation with shift, subtraction, multiplication */
q_ptr[ j ] *= SKP_dec_map( ec_dec_icdf( psRangeDec, icdf, 8 ) );
#endif
}
}
}
q_ptr += SHELL_CODEC_FRAME_LENGTH;
}
}