media/libopus/celt/entcode.h@ac0c01689b40 (annotated)
media/libopus/celt/entcode.h
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* Copyright (c) 2001-2011 Timothy B. Terriberry |
| michael@0 | 2 | Copyright (c) 2008-2009 Xiph.Org Foundation */ |
| michael@0 | 3 | /* |
| michael@0 | 4 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 5 | modification, are permitted provided that the following conditions |
| michael@0 | 6 | are met: |
| michael@0 | 7 | |
| michael@0 | 8 | - Redistributions of source code must retain the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer. |
| michael@0 | 10 | |
| michael@0 | 11 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 12 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 13 | documentation and/or other materials provided with the distribution. |
| michael@0 | 14 | |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| michael@0 | 16 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| michael@0 | 17 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| michael@0 | 18 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER |
| michael@0 | 19 | OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| michael@0 | 20 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| michael@0 | 21 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| michael@0 | 22 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| michael@0 | 23 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| michael@0 | 24 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| michael@0 | 25 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | */ |
| michael@0 | 27 | |
| michael@0 | 28 | #include "opus_types.h" |
| michael@0 | 29 | #include "opus_defines.h" |
| michael@0 | 30 | |
| michael@0 | 31 | #if !defined(_entcode_H) |
| michael@0 | 32 | # define _entcode_H (1) |
| michael@0 | 33 | # include <limits.h> |
| michael@0 | 34 | # include <stddef.h> |
| michael@0 | 35 | # include "ecintrin.h" |
| michael@0 | 36 | |
| michael@0 | 37 | /*OPT: ec_window must be at least 32 bits, but if you have fast arithmetic on a |
| michael@0 | 38 | larger type, you can speed up the decoder by using it here.*/ |
| michael@0 | 39 | typedef opus_uint32 ec_window; |
| michael@0 | 40 | typedef struct ec_ctx ec_ctx; |
| michael@0 | 41 | typedef struct ec_ctx ec_enc; |
| michael@0 | 42 | typedef struct ec_ctx ec_dec; |
| michael@0 | 43 | |
| michael@0 | 44 | # define EC_WINDOW_SIZE ((int)sizeof(ec_window)*CHAR_BIT) |
| michael@0 | 45 | |
| michael@0 | 46 | /*The number of bits to use for the range-coded part of unsigned integers.*/ |
| michael@0 | 47 | # define EC_UINT_BITS (8) |
| michael@0 | 48 | |
| michael@0 | 49 | /*The resolution of fractional-precision bit usage measurements, i.e., |
| michael@0 | 50 | 3 => 1/8th bits.*/ |
| michael@0 | 51 | # define BITRES 3 |
| michael@0 | 52 | |
| michael@0 | 53 | /*The entropy encoder/decoder context. |
| michael@0 | 54 | We use the same structure for both, so that common functions like ec_tell() |
| michael@0 | 55 | can be used on either one.*/ |
| michael@0 | 56 | struct ec_ctx{ |
| michael@0 | 57 | /*Buffered input/output.*/ |
| michael@0 | 58 | unsigned char *buf; |
| michael@0 | 59 | /*The size of the buffer.*/ |
| michael@0 | 60 | opus_uint32 storage; |
| michael@0 | 61 | /*The offset at which the last byte containing raw bits was read/written.*/ |
| michael@0 | 62 | opus_uint32 end_offs; |
| michael@0 | 63 | /*Bits that will be read from/written at the end.*/ |
| michael@0 | 64 | ec_window end_window; |
| michael@0 | 65 | /*Number of valid bits in end_window.*/ |
| michael@0 | 66 | int nend_bits; |
| michael@0 | 67 | /*The total number of whole bits read/written. |
| michael@0 | 68 | This does not include partial bits currently in the range coder.*/ |
| michael@0 | 69 | int nbits_total; |
| michael@0 | 70 | /*The offset at which the next range coder byte will be read/written.*/ |
| michael@0 | 71 | opus_uint32 offs; |
| michael@0 | 72 | /*The number of values in the current range.*/ |
| michael@0 | 73 | opus_uint32 rng; |
| michael@0 | 74 | /*In the decoder: the difference between the top of the current range and |
| michael@0 | 75 | the input value, minus one. |
| michael@0 | 76 | In the encoder: the low end of the current range.*/ |
| michael@0 | 77 | opus_uint32 val; |
| michael@0 | 78 | /*In the decoder: the saved normalization factor from ec_decode(). |
| michael@0 | 79 | In the encoder: the number of oustanding carry propagating symbols.*/ |
| michael@0 | 80 | opus_uint32 ext; |
| michael@0 | 81 | /*A buffered input/output symbol, awaiting carry propagation.*/ |
| michael@0 | 82 | int rem; |
| michael@0 | 83 | /*Nonzero if an error occurred.*/ |
| michael@0 | 84 | int error; |
| michael@0 | 85 | }; |
| michael@0 | 86 | |
| michael@0 | 87 | static OPUS_INLINE opus_uint32 ec_range_bytes(ec_ctx *_this){ |
| michael@0 | 88 | return _this->offs; |
| michael@0 | 89 | } |
| michael@0 | 90 | |
| michael@0 | 91 | static OPUS_INLINE unsigned char *ec_get_buffer(ec_ctx *_this){ |
| michael@0 | 92 | return _this->buf; |
| michael@0 | 93 | } |
| michael@0 | 94 | |
| michael@0 | 95 | static OPUS_INLINE int ec_get_error(ec_ctx *_this){ |
| michael@0 | 96 | return _this->error; |
| michael@0 | 97 | } |
| michael@0 | 98 | |
| michael@0 | 99 | /*Returns the number of bits "used" by the encoded or decoded symbols so far. |
| michael@0 | 100 | This same number can be computed in either the encoder or the decoder, and is |
| michael@0 | 101 | suitable for making coding decisions. |
| michael@0 | 102 | Return: The number of bits. |
| michael@0 | 103 | This will always be slightly larger than the exact value (e.g., all |
| michael@0 | 104 | rounding error is in the positive direction).*/ |
| michael@0 | 105 | static OPUS_INLINE int ec_tell(ec_ctx *_this){ |
| michael@0 | 106 | return _this->nbits_total-EC_ILOG(_this->rng); |
| michael@0 | 107 | } |
| michael@0 | 108 | |
| michael@0 | 109 | /*Returns the number of bits "used" by the encoded or decoded symbols so far. |
| michael@0 | 110 | This same number can be computed in either the encoder or the decoder, and is |
| michael@0 | 111 | suitable for making coding decisions. |
| michael@0 | 112 | Return: The number of bits scaled by 2**BITRES. |
| michael@0 | 113 | This will always be slightly larger than the exact value (e.g., all |
| michael@0 | 114 | rounding error is in the positive direction).*/ |
| michael@0 | 115 | opus_uint32 ec_tell_frac(ec_ctx *_this); |
| michael@0 | 116 | |
| michael@0 | 117 | #endif |
