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comparison libtwamr/if1_unpack.c @ 441:ebe499058c63

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libtwamr: implement API functions for RFC 4867 I/O
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 09 May 2024 07:06:31 +0000
parents amrconv/if1_unpack.c@934cf92a1c45
children
comparison
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440:bc736a8654af 441:ebe499058c63
1 /*
2 * In this module we implement our function for unpacking bits from AMR IF1
3 * and reshuffling them into the codec's natural bit order.
4 */
5
6 #include <stdint.h>
7 #include "tw_amr.h"
8 #include "typedef.h"
9 #include "namespace.h"
10 #include "int_defs.h"
11 #include "if1_func.h"
12
13 static inline Word16 msb_get_bit(const uint8_t *buf, Word16 bn)
14 {
15 Word16 pos_byte = bn >> 3;
16 Word16 pos_bit = 7 - (bn & 7);
17
18 return (buf[pos_byte] >> pos_bit) & 1;
19 }
20
21 static void unpack_bits(const uint8_t *if1_bytes, Word16 *codec_bits,
22 Word16 nbits, const uint8_t *table)
23 {
24 Word16 n, nb;
25
26 for (n = 0; n < nbits; n++) {
27 if (table)
28 nb = table[n];
29 else
30 nb = n;
31 codec_bits[nb] = msb_get_bit(if1_bytes, n);
32 }
33 }
34
35 void if1_unpack_bytes(enum Mode mode, const uint8_t *if1_bytes,
36 Word16 *serial_bits)
37 {
38 switch (mode) {
39 case MR475:
40 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_475, sort_475);
41 return;
42 case MR515:
43 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_515, sort_515);
44 return;
45 case MR59:
46 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_59, sort_59);
47 return;
48 case MR67:
49 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_67, sort_67);
50 return;
51 case MR74:
52 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_74, sort_74);
53 return;
54 case MR795:
55 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_795, sort_795);
56 return;
57 case MR102:
58 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_102, sort_102);
59 return;
60 case MR122:
61 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_122, sort_122);
62 return;
63 case MRDTX:
64 unpack_bits(if1_bytes, serial_bits, AMR_NBITS_SID,
65 (const uint8_t *) 0);
66 return;
67 }
68 }