1/* Copyright (c) 2001-2011 Timothy B. Terriberry
2   Copyright (c) 2008-2009 Xiph.Org Foundation */
3/*
4   Redistribution and use in source and binary forms, with or without
5   modification, are permitted provided that the following conditions
6   are met:
7
8   - Redistributions of source code must retain the above copyright
9   notice, this list of conditions and the following disclaimer.
10
11   - Redistributions in binary form must reproduce the above copyright
12   notice, this list of conditions and the following disclaimer in the
13   documentation and/or other materials provided with the distribution.
14
15   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
19   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
23   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*/
27
28#if !defined(_entenc_H)
29# define _entenc_H (1)
30# include <stddef.h>
31# include "entcode.h"
32
33/*Initializes the encoder.
34  _buf:  The buffer to store output bytes in.
35  _size: The size of the buffer, in chars.*/
36void ec_enc_init(ec_enc *_this,unsigned char *_buf,opus_uint32 _size);
37/*Encodes a symbol given its frequency information.
38  The frequency information must be discernable by the decoder, assuming it
39   has read only the previous symbols from the stream.
40  It is allowable to change the frequency information, or even the entire
41   source alphabet, so long as the decoder can tell from the context of the
42   previously encoded information that it is supposed to do so as well.
43  _fl: The cumulative frequency of all symbols that come before the one to be
44        encoded.
45  _fh: The cumulative frequency of all symbols up to and including the one to
46        be encoded.
47       Together with _fl, this defines the range [_fl,_fh) in which the
48        decoded value will fall.
49  _ft: The sum of the frequencies of all the symbols*/
50void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft);
51
52/*Equivalent to ec_encode() with _ft==1<<_bits.*/
53void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _bits);
54
55/* Encode a bit that has a 1/(1<<_logp) probability of being a one */
56void ec_enc_bit_logp(ec_enc *_this,int _val,unsigned _logp);
57
58/*Encodes a symbol given an "inverse" CDF table.
59  _s:    The index of the symbol to encode.
60  _icdf: The "inverse" CDF, such that symbol _s falls in the range
61          [_s>0?ft-_icdf[_s-1]:0,ft-_icdf[_s]), where ft=1<<_ftb.
62         The values must be monotonically non-increasing, and the last value
63          must be 0.
64  _ftb: The number of bits of precision in the cumulative distribution.*/
65void ec_enc_icdf(ec_enc *_this,int _s,const unsigned char *_icdf,unsigned _ftb);
66
67/*Encodes a raw unsigned integer in the stream.
68  _fl: The integer to encode.
69  _ft: The number of integers that can be encoded (one more than the max).
70       This must be at least one, and no more than 2**32-1.*/
71void ec_enc_uint(ec_enc *_this,opus_uint32 _fl,opus_uint32 _ft);
72
73/*Encodes a sequence of raw bits in the stream.
74  _fl:  The bits to encode.
75  _ftb: The number of bits to encode.
76        This must be between 1 and 25, inclusive.*/
77void ec_enc_bits(ec_enc *_this,opus_uint32 _fl,unsigned _ftb);
78
79/*Overwrites a few bits at the very start of an existing stream, after they
80   have already been encoded.
81  This makes it possible to have a few flags up front, where it is easy for
82   decoders to access them without parsing the whole stream, even if their
83   values are not determined until late in the encoding process, without having
84   to buffer all the intermediate symbols in the encoder.
85  In order for this to work, at least _nbits bits must have already been
86   encoded using probabilities that are an exact power of two.
87  The encoder can verify the number of encoded bits is sufficient, but cannot
88   check this latter condition.
89  _val:   The bits to encode (in the least _nbits significant bits).
90          They will be decoded in order from most-significant to least.
91  _nbits: The number of bits to overwrite.
92          This must be no more than 8.*/
93void ec_enc_patch_initial_bits(ec_enc *_this,unsigned _val,unsigned _nbits);
94
95/*Compacts the data to fit in the target size.
96  This moves up the raw bits at the end of the current buffer so they are at
97   the end of the new buffer size.
98  The caller must ensure that the amount of data that's already been written
99   will fit in the new size.
100  _size: The number of bytes in the new buffer.
101         This must be large enough to contain the bits already written, and
102          must be no larger than the existing size.*/
103void ec_enc_shrink(ec_enc *_this,opus_uint32 _size);
104
105/*Indicates that there are no more symbols to encode.
106  All reamining output bytes are flushed to the output buffer.
107  ec_enc_init() must be called before the encoder can be used again.*/
108void ec_enc_done(ec_enc *_this);
109
110#endif
111