1/***********************************************************************
2Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3Redistribution and use in source and binary forms, with or without
4modification, are permitted provided that the following conditions
5are met:
6- Redistributions of source code must retain the above copyright notice,
7this list of conditions and the following disclaimer.
8- Redistributions in binary form must reproduce the above copyright
9notice, this list of conditions and the following disclaimer in the
10documentation and/or other materials provided with the distribution.
11- Neither the name of Internet Society, IETF or IETF Trust, nor the
12names of specific contributors, may be used to endorse or promote
13products derived from this software without specific prior written
14permission.
15THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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24ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25POSSIBILITY OF SUCH DAMAGE.
26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "main.h"
33
34/* shell coder; pulse-subframe length is hardcoded */
35
36static OPUS_INLINE void combine_pulses(
37    opus_int         *out,   /* O    combined pulses vector [len] */
38    const opus_int   *in,    /* I    input vector       [2 * len] */
39    const opus_int   len     /* I    number of OUTPUT samples     */
40)
41{
42    opus_int k;
43    for( k = 0; k < len; k++ ) {
44        out[ k ] = in[ 2 * k ] + in[ 2 * k + 1 ];
45    }
46}
47
48static OPUS_INLINE void encode_split(
49    ec_enc                      *psRangeEnc,    /* I/O  compressor data structure                   */
50    const opus_int              p_child1,       /* I    pulse amplitude of first child subframe     */
51    const opus_int              p,              /* I    pulse amplitude of current subframe         */
52    const opus_uint8            *shell_table    /* I    table of shell cdfs                         */
53)
54{
55    if( p > 0 ) {
56        ec_enc_icdf( psRangeEnc, p_child1, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
57    }
58}
59
60static OPUS_INLINE void decode_split(
61    opus_int                    *p_child1,      /* O    pulse amplitude of first child subframe     */
62    opus_int                    *p_child2,      /* O    pulse amplitude of second child subframe    */
63    ec_dec                      *psRangeDec,    /* I/O  Compressor data structure                   */
64    const opus_int              p,              /* I    pulse amplitude of current subframe         */
65    const opus_uint8            *shell_table    /* I    table of shell cdfs                         */
66)
67{
68    if( p > 0 ) {
69        p_child1[ 0 ] = ec_dec_icdf( psRangeDec, &shell_table[ silk_shell_code_table_offsets[ p ] ], 8 );
70        p_child2[ 0 ] = p - p_child1[ 0 ];
71    } else {
72        p_child1[ 0 ] = 0;
73        p_child2[ 0 ] = 0;
74    }
75}
76
77/* Shell encoder, operates on one shell code frame of 16 pulses */
78void silk_shell_encoder(
79    ec_enc                      *psRangeEnc,                    /* I/O  compressor data structure                   */
80    const opus_int              *pulses0                        /* I    data: nonnegative pulse amplitudes          */
81)
82{
83    opus_int pulses1[ 8 ], pulses2[ 4 ], pulses3[ 2 ], pulses4[ 1 ];
84
85    /* this function operates on one shell code frame of 16 pulses */
86    silk_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
87
88    /* tree representation per pulse-subframe */
89    combine_pulses( pulses1, pulses0, 8 );
90    combine_pulses( pulses2, pulses1, 4 );
91    combine_pulses( pulses3, pulses2, 2 );
92    combine_pulses( pulses4, pulses3, 1 );
93
94    encode_split( psRangeEnc, pulses3[  0 ], pulses4[ 0 ], silk_shell_code_table3 );
95
96    encode_split( psRangeEnc, pulses2[  0 ], pulses3[ 0 ], silk_shell_code_table2 );
97
98    encode_split( psRangeEnc, pulses1[  0 ], pulses2[ 0 ], silk_shell_code_table1 );
99    encode_split( psRangeEnc, pulses0[  0 ], pulses1[ 0 ], silk_shell_code_table0 );
100    encode_split( psRangeEnc, pulses0[  2 ], pulses1[ 1 ], silk_shell_code_table0 );
101
102    encode_split( psRangeEnc, pulses1[  2 ], pulses2[ 1 ], silk_shell_code_table1 );
103    encode_split( psRangeEnc, pulses0[  4 ], pulses1[ 2 ], silk_shell_code_table0 );
104    encode_split( psRangeEnc, pulses0[  6 ], pulses1[ 3 ], silk_shell_code_table0 );
105
106    encode_split( psRangeEnc, pulses2[  2 ], pulses3[ 1 ], silk_shell_code_table2 );
107
108    encode_split( psRangeEnc, pulses1[  4 ], pulses2[ 2 ], silk_shell_code_table1 );
109    encode_split( psRangeEnc, pulses0[  8 ], pulses1[ 4 ], silk_shell_code_table0 );
110    encode_split( psRangeEnc, pulses0[ 10 ], pulses1[ 5 ], silk_shell_code_table0 );
111
112    encode_split( psRangeEnc, pulses1[  6 ], pulses2[ 3 ], silk_shell_code_table1 );
113    encode_split( psRangeEnc, pulses0[ 12 ], pulses1[ 6 ], silk_shell_code_table0 );
114    encode_split( psRangeEnc, pulses0[ 14 ], pulses1[ 7 ], silk_shell_code_table0 );
115}
116
117
118/* Shell decoder, operates on one shell code frame of 16 pulses */
119void silk_shell_decoder(
120    opus_int                    *pulses0,                       /* O    data: nonnegative pulse amplitudes          */
121    ec_dec                      *psRangeDec,                    /* I/O  Compressor data structure                   */
122    const opus_int              pulses4                         /* I    number of pulses per pulse-subframe         */
123)
124{
125    opus_int pulses3[ 2 ], pulses2[ 4 ], pulses1[ 8 ];
126
127    /* this function operates on one shell code frame of 16 pulses */
128    silk_assert( SHELL_CODEC_FRAME_LENGTH == 16 );
129
130    decode_split( &pulses3[  0 ], &pulses3[  1 ], psRangeDec, pulses4,      silk_shell_code_table3 );
131
132    decode_split( &pulses2[  0 ], &pulses2[  1 ], psRangeDec, pulses3[ 0 ], silk_shell_code_table2 );
133
134    decode_split( &pulses1[  0 ], &pulses1[  1 ], psRangeDec, pulses2[ 0 ], silk_shell_code_table1 );
135    decode_split( &pulses0[  0 ], &pulses0[  1 ], psRangeDec, pulses1[ 0 ], silk_shell_code_table0 );
136    decode_split( &pulses0[  2 ], &pulses0[  3 ], psRangeDec, pulses1[ 1 ], silk_shell_code_table0 );
137
138    decode_split( &pulses1[  2 ], &pulses1[  3 ], psRangeDec, pulses2[ 1 ], silk_shell_code_table1 );
139    decode_split( &pulses0[  4 ], &pulses0[  5 ], psRangeDec, pulses1[ 2 ], silk_shell_code_table0 );
140    decode_split( &pulses0[  6 ], &pulses0[  7 ], psRangeDec, pulses1[ 3 ], silk_shell_code_table0 );
141
142    decode_split( &pulses2[  2 ], &pulses2[  3 ], psRangeDec, pulses3[ 1 ], silk_shell_code_table2 );
143
144    decode_split( &pulses1[  4 ], &pulses1[  5 ], psRangeDec, pulses2[ 2 ], silk_shell_code_table1 );
145    decode_split( &pulses0[  8 ], &pulses0[  9 ], psRangeDec, pulses1[ 4 ], silk_shell_code_table0 );
146    decode_split( &pulses0[ 10 ], &pulses0[ 11 ], psRangeDec, pulses1[ 5 ], silk_shell_code_table0 );
147
148    decode_split( &pulses1[  6 ], &pulses1[  7 ], psRangeDec, pulses2[ 3 ], silk_shell_code_table1 );
149    decode_split( &pulses0[ 12 ], &pulses0[ 13 ], psRangeDec, pulses1[ 6 ], silk_shell_code_table0 );
150    decode_split( &pulses0[ 14 ], &pulses0[ 15 ], psRangeDec, pulses1[ 7 ], silk_shell_code_table0 );
151}
152