ref: 894f1cf51b87a95b7faa782ca2e01c78bc0de610
dir: /src_common/SKP_Silk_range_coder.c/
/***********************************************************************
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***********************************************************************/
#include "SKP_Silk_main.h"
#define MAX_SIZE 10000
/* Range encoder for one symbol */
void SKP_Silk_range_encoder(
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_int data, /* I uncompressed data */
const SKP_uint16 prob[] /* I cumulative density functions */
)
{
SKP_uint32 low_Q16, high_Q16;
if( psRC->error ) {
return;
}
low_Q16 = prob[ data ];
high_Q16 = prob[ data + 1 ];
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( enc_l.dat, &low_Q16, sizeof(SKP_uint32) );
DEBUG_STORE_DATA( enc_h.dat, &high_Q16, sizeof(SKP_uint32) );
DEBUG_STORE_DATA( enc.dat, &data, sizeof(SKP_int) );
#endif
if( prob[ 2 ] == 65535 ) {
/* Instead of detection, we could add a separate function and call when we know that input is a bit */
ec_enc_bit_prob( &psRC->range_enc_celt_state, data, 65536 - prob[ 1 ] );
} else {
ec_encode_bin( &psRC->range_enc_celt_state, low_Q16, high_Q16, 16 );
}
}
/* Range encoder for one symbol, with uniform PDF*/
void SKP_Silk_range_encode_uniform(
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_int data, /* I uncompressed data */
const SKP_int N /* I number of possible outcomes */
)
{
SKP_int i;
SKP_uint16 delta, prob[ MAX_SIZE + 1 ];
SKP_assert( N < MAX_SIZE );
delta = ( SKP_uint16 )SKP_DIV32_16( 65535, N );
prob[ 0 ] = 0;
for( i = 0; i < N - 1; i++ ) {
prob[ i + 1 ] = prob[ i ] + delta;
}
prob[ N ] = 65535;
SKP_Silk_range_encoder( psRC, data, prob );
}
/* Range encoder for multiple symbols */
void SKP_Silk_range_encoder_multi(
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_int data[], /* I uncompressed data [nSymbols] */
const SKP_uint16 * const prob[], /* I cumulative density functions */
const SKP_int nSymbols /* I number of data symbols */
)
{
SKP_int k;
for( k = 0; k < nSymbols; k++ ) {
SKP_Silk_range_encoder( psRC, data[ k ], prob[ k ] );
}
}
/* Range decoder for one symbol */
void SKP_Silk_range_decoder(
SKP_int data[], /* O uncompressed data */
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_uint16 prob[], /* I cumulative density function */
SKP_int probIx /* I initial (middle) entry of cdf */
)
{
SKP_uint32 low_Q16, high_Q16;
SKP_uint32 low_Q16_returned;
SKP_int temp;
if( psRC->error ) {
/* Set output to zero */
*data = 0;
return;
}
if( prob[ 2 ] == 65535 ) {
/* Instead of detection, we could add a separate function and call when we know that output is a bit */
*data = ec_dec_bit_prob( &psRC->range_dec_celt_state, 65536 - prob[ 1 ] );
} else {
low_Q16_returned = ec_decode_bin( &psRC->range_dec_celt_state, 16 );
}
/* OPTIMIZE ME WITH BI-SECTION */
if( prob[ 2 ] != 65535 ) {
#if 1
temp = 0;
while( low_Q16_returned >= prob[ ++temp ] ) {}
*data = temp - 1;
#else
temp = probIx;
if( low_Q16_returned >= prob[ temp ] ){
while( low_Q16_returned >= prob[ temp ] ) {
temp++;
}
temp = temp - 1;
} else {
/* search down */
while( low_Q16_returned < prob[ temp ] ) {
temp--;
}
}
*data = temp;
#endif
low_Q16 = prob[ *data ];
high_Q16 = prob[ *data + 1 ];
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( dec_lr.dat, &low_Q16_returned, sizeof( SKP_uint32 ) );
DEBUG_STORE_DATA( dec_l.dat, &low_Q16, sizeof( SKP_uint32 ) );
DEBUG_STORE_DATA( dec_h.dat, &high_Q16, sizeof( SKP_uint32 ) );
#endif
ec_dec_update( &psRC->range_dec_celt_state, low_Q16, high_Q16,( 1 << 16 ) );
}
#ifdef SAVE_ALL_INTERNAL_DATA
DEBUG_STORE_DATA( dec.dat, data, sizeof( SKP_int ) );
#endif
}
/* Range decoder for one symbol, with uniform PDF*/
void SKP_Silk_range_decode_uniform(
SKP_int data[], /* O uncompressed data */
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_int N /* I number of possible outcomes */
)
{
SKP_int i;
SKP_uint16 delta, prob[ MAX_SIZE + 1 ];
SKP_assert( N < MAX_SIZE );
delta = ( SKP_uint16 )SKP_DIV32_16( 65535, N );
prob[ 0 ] = 0;
for( i = 0; i < N - 1; i++ ) {
prob[ i + 1 ] = prob[ i ] + delta;
}
prob[ N ] = 65535;
SKP_Silk_range_decoder( data, psRC, prob, ( N >> 1 ) );
}
/* Range decoder for multiple symbols */
void SKP_Silk_range_decoder_multi(
SKP_int data[], /* O uncompressed data [nSymbols] */
SKP_Silk_range_coder_state *psRC, /* I/O compressor data structure */
const SKP_uint16 * const prob[], /* I cumulative density functions */
const SKP_int probStartIx[], /* I initial (middle) entries of cdfs [nSymbols] */
const SKP_int nSymbols /* I number of data symbols */
)
{
SKP_int k;
for( k = 0; k < nSymbols; k++ ) {
SKP_Silk_range_decoder( &data[ k ], psRC, prob[ k ], probStartIx[ k ] );
}
}
/* Initialize range encoder */
void SKP_Silk_range_enc_init(
SKP_Silk_range_coder_state *psRC /* O compressor data structure */
)
{
psRC->error = 0;
}
/* Initialize range decoder */
void SKP_Silk_range_dec_init(
SKP_Silk_range_coder_state *psRC, /* O compressor data structure */
const SKP_uint8 buffer[], /* I buffer for compressed data [bufferLength] */
const SKP_int32 bufferLength /* I buffer length (in bytes) */
)
{
/* check input */
if( bufferLength > MAX_ARITHM_BYTES ) {
psRC->error = RANGE_CODER_DEC_PAYLOAD_TOO_LONG;
return;
}
/* Initialize structure */
/* Copy to internal buffer */
SKP_memcpy( psRC->buffer, buffer, bufferLength * sizeof( SKP_uint8 ) );
psRC->bufferLength = bufferLength;
psRC->bufferIx = 0;
psRC->base_Q32 =
SKP_LSHIFT_uint( ( SKP_uint32 )buffer[ 0 ], 24 ) |
SKP_LSHIFT_uint( ( SKP_uint32 )buffer[ 1 ], 16 ) |
SKP_LSHIFT_uint( ( SKP_uint32 )buffer[ 2 ], 8 ) |
( SKP_uint32 )buffer[ 3 ];
psRC->range_Q16 = 0x0000FFFF;
psRC->error = 0;
}
/* Determine length of bitstream */
SKP_int SKP_Silk_range_encoder_get_length( /* O returns number of BITS in stream */
SKP_Silk_range_coder_state *psRC, /* I compressed data structure */
SKP_int *nBytes /* O number of BYTES in stream */
)
{
SKP_int nBits;
/* Get number of bits in bitstream */
nBits = ec_enc_tell( &psRC->range_enc_celt_state, 0 );
/* Round up to an integer number of bytes */
*nBytes = SKP_RSHIFT( nBits + 7, 3 );
/* Return number of bits in bitstream */
return nBits;
}
/* Determine length of bitstream */
SKP_int SKP_Silk_range_decoder_get_length( /* O returns number of BITS in stream */
SKP_Silk_range_coder_state *psRC, /* I compressed data structure */
SKP_int *nBytes /* O number of BYTES in stream */
)
{
SKP_int nBits;
/* Get number of bits in bitstream */
nBits = ec_dec_tell( &psRC->range_dec_celt_state, 0 );
/* Round up to an integer number of bytes */
*nBytes = SKP_RSHIFT( nBits + 7, 3 );
/* Return number of bits in bitstream */
return nBits;
}
/* Check that any remaining bits in the last byte are set to 1 */
void SKP_Silk_range_coder_check_after_decoding(
SKP_Silk_range_coder_state *psRC /* I/O compressed data structure */
)
{
SKP_int bits_in_stream, nBytes, mask;
bits_in_stream = SKP_Silk_range_decoder_get_length( psRC, &nBytes );
/* Make sure not to read beyond buffer */
if( nBytes - 1 >= psRC->range_dec_celt_state.buf->storage ) {
psRC->error = RANGE_CODER_DECODER_CHECK_FAILED;
return;
}
/* Test any remaining bits in last byte */
if( bits_in_stream & 7 ) {
mask = SKP_RSHIFT( 0xFF, bits_in_stream & 7 );
if( ( psRC->range_dec_celt_state.buf->buf[ nBytes - 1 ] & mask ) != mask ) {
psRC->error = RANGE_CODER_DECODER_CHECK_FAILED;
return;
}
}
}