136 lines
4.8 KiB
C
136 lines
4.8 KiB
C
/* 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.
|
|
|
|
- Neither the name of the Xiph.org Foundation nor the names of its
|
|
contributors may be used to endorse or promote products derived from
|
|
this software without specific prior written permission.
|
|
|
|
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 FOUNDATION 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.
|
|
*/
|
|
|
|
#include "celt_types.h"
|
|
|
|
#if !defined(_entcode_H)
|
|
# define _entcode_H (1)
|
|
# include <limits.h>
|
|
# include <stddef.h>
|
|
# include "ecintrin.h"
|
|
|
|
|
|
|
|
typedef celt_int32 ec_int32;
|
|
typedef celt_uint32 ec_uint32;
|
|
typedef size_t ec_window;
|
|
typedef struct ec_ctx ec_ctx;
|
|
typedef struct ec_ctx ec_enc;
|
|
typedef struct ec_ctx ec_dec;
|
|
|
|
|
|
|
|
/*This must be at least 32 bits.*/
|
|
# define EC_WINDOW_SIZE ((int)sizeof(ec_window)*CHAR_BIT)
|
|
|
|
/*The number of bits to use for the range-coded part of unsigned integers.*/
|
|
# define EC_UINT_BITS (8)
|
|
|
|
/*The resolution of fractional-precision bit usage measurements, i.e.,
|
|
3 => 1/8th bits.*/
|
|
# define BITRES 3
|
|
|
|
|
|
|
|
/*The entropy encoder/decoder context.
|
|
We use the same structure for both, so that common functions like ec_tell()
|
|
can be used on either one.*/
|
|
struct ec_ctx{
|
|
/*Buffered input/output.*/
|
|
unsigned char *buf;
|
|
/*The size of the buffer.*/
|
|
ec_uint32 storage;
|
|
/*The offset at which the last byte containing raw bits was read/written.*/
|
|
ec_uint32 end_offs;
|
|
/*Bits that will be read from/written at the end.*/
|
|
ec_window end_window;
|
|
/*Number of valid bits in end_window.*/
|
|
int nend_bits;
|
|
/*The total number of whole bits read/written.
|
|
This does not include partial bits currently in the range coder.*/
|
|
int nbits_total;
|
|
/*The offset at which the next range coder byte will be read/written.*/
|
|
ec_uint32 offs;
|
|
/*The number of values in the current range.*/
|
|
ec_uint32 rng;
|
|
/*In the decoder: the difference between the top of the current range and
|
|
the input value, minus one.
|
|
In the encoder: the low end of the current range.*/
|
|
ec_uint32 val;
|
|
/*In the decoder: the saved normalization factor from ec_decode().
|
|
In the encoder: the number of oustanding carry propagating symbols.*/
|
|
ec_uint32 ext;
|
|
/*A buffered input/output symbol, awaiting carry propagation.*/
|
|
int rem;
|
|
/*Nonzero if an error occurred.*/
|
|
int error;
|
|
};
|
|
|
|
|
|
/*Shared functions.*/
|
|
static inline void ec_reset(ec_ctx *_this){
|
|
_this->offs=_this->end_offs=0;
|
|
}
|
|
|
|
static inline ec_uint32 ec_range_bytes(ec_ctx *_this){
|
|
return _this->offs;
|
|
}
|
|
|
|
static inline unsigned char *ec_get_buffer(ec_ctx *_this){
|
|
return _this->buf;
|
|
}
|
|
|
|
static inline int ec_get_error(ec_ctx *_this){
|
|
return _this->error;
|
|
}
|
|
|
|
int ec_ilog(ec_uint32 _v);
|
|
|
|
/*Returns the number of bits "used" by the encoded or decoded symbols so far.
|
|
This same number can be computed in either the encoder or the decoder, and is
|
|
suitable for making coding decisions.
|
|
Return: The number of bits.
|
|
This will always be slightly larger than the exact value (e.g., all
|
|
rounding error is in the positive direction).*/
|
|
static inline int ec_tell(ec_ctx *_this){
|
|
return _this->nbits_total-EC_ILOG(_this->rng);
|
|
}
|
|
|
|
/*Returns the number of bits "used" by the encoded or decoded symbols so far.
|
|
This same number can be computed in either the encoder or the decoder, and is
|
|
suitable for making coding decisions.
|
|
Return: The number of bits scaled by 2**BITRES.
|
|
This will always be slightly larger than the exact value (e.g., all
|
|
rounding error is in the positive direction).*/
|
|
ec_uint32 ec_tell_frac(ec_ctx *_this);
|
|
|
|
#endif
|