| /* Copyright (c) 2001-2011 Timothy B. Terriberry |
| Copyright (c) 2008-2009 Xiph.Org Foundation */ |
| /* |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| |
| - Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| |
| - Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER |
| OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #if !defined(_entenc_H) |
| # define _entenc_H (1) |
| # include <stddef.h> |
| # include "entcode.h" |
| |
| /*Initializes the encoder. |
| _buf: The buffer to store output bytes in. |
| _size: The size of the buffer, in chars.*/ |
| void ec_enc_init(ec_enc *_this,unsigned char *_buf,opus_uint32 _size); |
| /*Encodes a symbol given its frequency information. |
| The frequency information must be discernable by the decoder, assuming it |
| has read only the previous symbols from the stream. |
| It is allowable to change the frequency information, or even the entire |
| source alphabet, so long as the decoder can tell from the context of the |
| previously encoded information that it is supposed to do so as well. |
| _fl: The cumulative frequency of all symbols that come before the one to be |
| encoded. |
| _fh: The cumulative frequency of all symbols up to and including the one to |
| be encoded. |
| Together with _fl, this defines the range [_fl,_fh) in which the |
| decoded value will fall. |
| _ft: The sum of the frequencies of all the symbols*/ |
| void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft); |
| |
| /*Equivalent to ec_encode() with _ft==1<<_bits.*/ |
| void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _bits); |
| |
| /* Encode a bit that has a 1/(1<<_logp) probability of being a one */ |
| void ec_enc_bit_logp(ec_enc *_this,int _val,unsigned _logp); |
| |
| /*Encodes a symbol given an "inverse" CDF table. |
| _s: The index of the symbol to encode. |
| _icdf: The "inverse" CDF, such that symbol _s falls in the range |
| [_s>0?ft-_icdf[_s-1]:0,ft-_icdf[_s]), where ft=1<<_ftb. |
| The values must be monotonically non-increasing, and the last value |
| must be 0. |
| _ftb: The number of bits of precision in the cumulative distribution.*/ |
| void ec_enc_icdf(ec_enc *_this,int _s,const unsigned char *_icdf,unsigned _ftb); |
| |
| /*Encodes a raw unsigned integer in the stream. |
| _fl: The integer to encode. |
| _ft: The number of integers that can be encoded (one more than the max). |
| This must be at least one, and no more than 2**32-1.*/ |
| void ec_enc_uint(ec_enc *_this,opus_uint32 _fl,opus_uint32 _ft); |
| |
| /*Encodes a sequence of raw bits in the stream. |
| _fl: The bits to encode. |
| _ftb: The number of bits to encode. |
| This must be between 1 and 25, inclusive.*/ |
| void ec_enc_bits(ec_enc *_this,opus_uint32 _fl,unsigned _ftb); |
| |
| /*Overwrites a few bits at the very start of an existing stream, after they |
| have already been encoded. |
| This makes it possible to have a few flags up front, where it is easy for |
| decoders to access them without parsing the whole stream, even if their |
| values are not determined until late in the encoding process, without having |
| to buffer all the intermediate symbols in the encoder. |
| In order for this to work, at least _nbits bits must have already been |
| encoded using probabilities that are an exact power of two. |
| The encoder can verify the number of encoded bits is sufficient, but cannot |
| check this latter condition. |
| _val: The bits to encode (in the least _nbits significant bits). |
| They will be decoded in order from most-significant to least. |
| _nbits: The number of bits to overwrite. |
| This must be no more than 8.*/ |
| void ec_enc_patch_initial_bits(ec_enc *_this,unsigned _val,unsigned _nbits); |
| |
| /*Compacts the data to fit in the target size. |
| This moves up the raw bits at the end of the current buffer so they are at |
| the end of the new buffer size. |
| The caller must ensure that the amount of data that's already been written |
| will fit in the new size. |
| _size: The number of bytes in the new buffer. |
| This must be large enough to contain the bits already written, and |
| must be no larger than the existing size.*/ |
| void ec_enc_shrink(ec_enc *_this,opus_uint32 _size); |
| |
| /*Indicates that there are no more symbols to encode. |
| All reamining output bytes are flushed to the output buffer. |
| ec_enc_init() must be called before the encoder can be used again.*/ |
| void ec_enc_done(ec_enc *_this); |
| |
| #endif |