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author | Sean Bartell <wingedtachikoma@gmail.com> | 2011-06-25 21:32:25 -0400 |
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committer | Nils Wallménius <nils@rockbox.org> | 2012-04-25 22:13:20 +0200 |
commit | f40bfc9267b13b54e6379dfe7539447662879d24 (patch) | |
tree | 9b20069d5e62809ff434061ad730096836f916f2 /lib/rbcodec/codecs/liba52/bitstream.c | |
parent | a0009907de7a0107d49040d8a180f140e2eff299 (diff) | |
download | rockbox-f40bfc9267b13b54e6379dfe7539447662879d24.tar.gz rockbox-f40bfc9267b13b54e6379dfe7539447662879d24.zip |
Add codecs to librbcodec.
Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97
Reviewed-on: http://gerrit.rockbox.org/137
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Tested-by: Nils Wallménius <nils@rockbox.org>
Diffstat (limited to 'lib/rbcodec/codecs/liba52/bitstream.c')
-rw-r--r-- | lib/rbcodec/codecs/liba52/bitstream.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/liba52/bitstream.c b/lib/rbcodec/codecs/liba52/bitstream.c new file mode 100644 index 0000000000..155368f1ed --- /dev/null +++ b/lib/rbcodec/codecs/liba52/bitstream.c | |||
@@ -0,0 +1,97 @@ | |||
1 | /* | ||
2 | * bitstream.c | ||
3 | * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org> | ||
4 | * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca> | ||
5 | * | ||
6 | * This file is part of a52dec, a free ATSC A-52 stream decoder. | ||
7 | * See http://liba52.sourceforge.net/ for updates. | ||
8 | * | ||
9 | * a52dec is free software; you can redistribute it and/or modify | ||
10 | * it under the terms of the GNU General Public License as published by | ||
11 | * the Free Software Foundation; either version 2 of the License, or | ||
12 | * (at your option) any later version. | ||
13 | * | ||
14 | * a52dec is distributed in the hope that it will be useful, | ||
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
17 | * GNU General Public License for more details. | ||
18 | * | ||
19 | * You should have received a copy of the GNU General Public License | ||
20 | * along with this program; if not, write to the Free Software | ||
21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
22 | */ | ||
23 | |||
24 | #include "config-a52.h" | ||
25 | |||
26 | #include <inttypes.h> | ||
27 | |||
28 | #include "a52.h" | ||
29 | #include "a52_internal.h" | ||
30 | #include "bitstream.h" | ||
31 | |||
32 | #define BUFFER_SIZE 4096 | ||
33 | |||
34 | void a52_bitstream_set_ptr (a52_state_t * state, uint8_t * buf) | ||
35 | { | ||
36 | int align; | ||
37 | |||
38 | align = (long)buf & 3; | ||
39 | state->buffer_start = (uint32_t *) (buf - align); | ||
40 | state->bits_left = 0; | ||
41 | state->current_word = 0; | ||
42 | bitstream_get (state, align * 8); | ||
43 | bitstream_get_2 (state, 0); /* pretend function is used - keep gcc happy */ | ||
44 | } | ||
45 | |||
46 | static inline void bitstream_fill_current (a52_state_t * state) | ||
47 | { | ||
48 | uint32_t tmp; | ||
49 | |||
50 | tmp = *(state->buffer_start++); | ||
51 | state->current_word = swab32 (tmp); | ||
52 | } | ||
53 | |||
54 | /* | ||
55 | * The fast paths for _get is in the | ||
56 | * bitstream.h header file so it can be inlined. | ||
57 | * | ||
58 | * The "bottom half" of this routine is suffixed _bh | ||
59 | * | ||
60 | * -ah | ||
61 | */ | ||
62 | |||
63 | uint32_t a52_bitstream_get_bh (a52_state_t * state, uint32_t num_bits) | ||
64 | { | ||
65 | uint32_t result; | ||
66 | |||
67 | num_bits -= state->bits_left; | ||
68 | result = ((state->current_word << (32 - state->bits_left)) >> | ||
69 | (32 - state->bits_left)); | ||
70 | |||
71 | bitstream_fill_current (state); | ||
72 | |||
73 | if (num_bits != 0) | ||
74 | result = (result << num_bits) | (state->current_word >> (32 - num_bits)); | ||
75 | |||
76 | state->bits_left = 32 - num_bits; | ||
77 | |||
78 | return result; | ||
79 | } | ||
80 | |||
81 | int32_t a52_bitstream_get_bh_2 (a52_state_t * state, uint32_t num_bits) | ||
82 | { | ||
83 | int32_t result; | ||
84 | |||
85 | num_bits -= state->bits_left; | ||
86 | result = ((((int32_t)state->current_word) << (32 - state->bits_left)) >> | ||
87 | (32 - state->bits_left)); | ||
88 | |||
89 | bitstream_fill_current(state); | ||
90 | |||
91 | if (num_bits != 0) | ||
92 | result = (result << num_bits) | (state->current_word >> (32 - num_bits)); | ||
93 | |||
94 | state->bits_left = 32 - num_bits; | ||
95 | |||
96 | return result; | ||
97 | } | ||