media/libopus/celt/entdec.h@ac0c01689b40 (annotated)
media/libopus/celt/entdec.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 | #if !defined(_entdec_H) |
| michael@0 | 29 | # define _entdec_H (1) |
| michael@0 | 30 | # include <limits.h> |
| michael@0 | 31 | # include "entcode.h" |
| michael@0 | 32 | |
| michael@0 | 33 | /*Initializes the decoder. |
| michael@0 | 34 | _buf: The input buffer to use. |
| michael@0 | 35 | Return: 0 on success, or a negative value on error.*/ |
| michael@0 | 36 | void ec_dec_init(ec_dec *_this,unsigned char *_buf,opus_uint32 _storage); |
| michael@0 | 37 | |
| michael@0 | 38 | /*Calculates the cumulative frequency for the next symbol. |
| michael@0 | 39 | This can then be fed into the probability model to determine what that |
| michael@0 | 40 | symbol is, and the additional frequency information required to advance to |
| michael@0 | 41 | the next symbol. |
| michael@0 | 42 | This function cannot be called more than once without a corresponding call to |
| michael@0 | 43 | ec_dec_update(), or decoding will not proceed correctly. |
| michael@0 | 44 | _ft: The total frequency of the symbols in the alphabet the next symbol was |
| michael@0 | 45 | encoded with. |
| michael@0 | 46 | Return: A cumulative frequency representing the encoded symbol. |
| michael@0 | 47 | If the cumulative frequency of all the symbols before the one that |
| michael@0 | 48 | was encoded was fl, and the cumulative frequency of all the symbols |
| michael@0 | 49 | up to and including the one encoded is fh, then the returned value |
| michael@0 | 50 | will fall in the range [fl,fh).*/ |
| michael@0 | 51 | unsigned ec_decode(ec_dec *_this,unsigned _ft); |
| michael@0 | 52 | |
| michael@0 | 53 | /*Equivalent to ec_decode() with _ft==1<<_bits.*/ |
| michael@0 | 54 | unsigned ec_decode_bin(ec_dec *_this,unsigned _bits); |
| michael@0 | 55 | |
| michael@0 | 56 | /*Advance the decoder past the next symbol using the frequency information the |
| michael@0 | 57 | symbol was encoded with. |
| michael@0 | 58 | Exactly one call to ec_decode() must have been made so that all necessary |
| michael@0 | 59 | intermediate calculations are performed. |
| michael@0 | 60 | _fl: The cumulative frequency of all symbols that come before the symbol |
| michael@0 | 61 | decoded. |
| michael@0 | 62 | _fh: The cumulative frequency of all symbols up to and including the symbol |
| michael@0 | 63 | decoded. |
| michael@0 | 64 | Together with _fl, this defines the range [_fl,_fh) in which the value |
| michael@0 | 65 | returned above must fall. |
| michael@0 | 66 | _ft: The total frequency of the symbols in the alphabet the symbol decoded |
| michael@0 | 67 | was encoded in. |
| michael@0 | 68 | This must be the same as passed to the preceding call to ec_decode().*/ |
| michael@0 | 69 | void ec_dec_update(ec_dec *_this,unsigned _fl,unsigned _fh,unsigned _ft); |
| michael@0 | 70 | |
| michael@0 | 71 | /* Decode a bit that has a 1/(1<<_logp) probability of being a one */ |
| michael@0 | 72 | int ec_dec_bit_logp(ec_dec *_this,unsigned _logp); |
| michael@0 | 73 | |
| michael@0 | 74 | /*Decodes a symbol given an "inverse" CDF table. |
| michael@0 | 75 | No call to ec_dec_update() is necessary after this call. |
| michael@0 | 76 | _icdf: The "inverse" CDF, such that symbol s falls in the range |
| michael@0 | 77 | [s>0?ft-_icdf[s-1]:0,ft-_icdf[s]), where ft=1<<_ftb. |
| michael@0 | 78 | The values must be monotonically non-increasing, and the last value |
| michael@0 | 79 | must be 0. |
| michael@0 | 80 | _ftb: The number of bits of precision in the cumulative distribution. |
| michael@0 | 81 | Return: The decoded symbol s.*/ |
| michael@0 | 82 | int ec_dec_icdf(ec_dec *_this,const unsigned char *_icdf,unsigned _ftb); |
| michael@0 | 83 | |
| michael@0 | 84 | /*Extracts a raw unsigned integer with a non-power-of-2 range from the stream. |
| michael@0 | 85 | The bits must have been encoded with ec_enc_uint(). |
| michael@0 | 86 | No call to ec_dec_update() is necessary after this call. |
| michael@0 | 87 | _ft: The number of integers that can be decoded (one more than the max). |
| michael@0 | 88 | This must be at least one, and no more than 2**32-1. |
| michael@0 | 89 | Return: The decoded bits.*/ |
| michael@0 | 90 | opus_uint32 ec_dec_uint(ec_dec *_this,opus_uint32 _ft); |
| michael@0 | 91 | |
| michael@0 | 92 | /*Extracts a sequence of raw bits from the stream. |
| michael@0 | 93 | The bits must have been encoded with ec_enc_bits(). |
| michael@0 | 94 | No call to ec_dec_update() is necessary after this call. |
| michael@0 | 95 | _ftb: The number of bits to extract. |
| michael@0 | 96 | This must be between 0 and 25, inclusive. |
| michael@0 | 97 | Return: The decoded bits.*/ |
| michael@0 | 98 | opus_uint32 ec_dec_bits(ec_dec *_this,unsigned _ftb); |
| michael@0 | 99 | |
| michael@0 | 100 | #endif |
