chromium/third_party/dav1d/libdav1d/src/msac.c

/*
 * Copyright © 2018, VideoLAN and dav1d authors
 * Copyright © 2018, Two Orioles, LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. 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.
 */

#include "config.h"

#include <limits.h>

#include "common/intops.h"

#include "src/msac.h"

#define EC_PROB_SHIFT …
#define EC_MIN_PROB …

#define EC_WIN_SIZE …

static inline void ctx_refill(MsacContext *const s) { … }

int dav1d_msac_decode_subexp(MsacContext *const s, const int ref,
                             const int n, unsigned k)
{ … }

#if !(HAVE_ASM && TRIM_DSP_FUNCTIONS && ( \
  ARCH_AARCH64 || \
  (ARCH_ARM && (defined(__ARM_NEON) || defined(__APPLE__) || defined(_WIN32))) \
))
/* Takes updated dif and range values, renormalizes them so that
 * 32768 <= rng < 65536 (reading more bytes from the stream into dif if
 * necessary), and stores them back in the decoder context.
 * dif: The new value of dif.
 * rng: The new value of the range. */
static inline void ctx_norm(MsacContext *const s, const ec_win dif,
                            const unsigned rng)
{ … }

unsigned dav1d_msac_decode_bool_equi_c(MsacContext *const s) { … }

/* Decode a single binary value.
 * f: The probability that the bit is one
 * Return: The value decoded (0 or 1). */
unsigned dav1d_msac_decode_bool_c(MsacContext *const s, const unsigned f) { … }

/* Decodes a symbol given an inverse cumulative distribution function (CDF)
 * table in Q15. */
unsigned dav1d_msac_decode_symbol_adapt_c(MsacContext *const s,
                                          uint16_t *const cdf,
                                          const size_t n_symbols)
{ … }

unsigned dav1d_msac_decode_bool_adapt_c(MsacContext *const s,
                                        uint16_t *const cdf)
{ … }

unsigned dav1d_msac_decode_hi_tok_c(MsacContext *const s, uint16_t *const cdf) { … }
#endif

void dav1d_msac_init(MsacContext *const s, const uint8_t *const data,
                     const size_t sz, const int disable_cdf_update_flag)
{ … }