token_enc.c | Explore in Territory

// Copyright 2011 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Paginated token buffer
//
//  A 'token' is a bit value associated with a probability, either fixed
// or a later-to-be-determined after statistics have been collected.
// For dynamic probability, we just record the slot id (idx) for the probability
// value in the final probability array (uint8_t* probas in VP8EmitTokens).
//
// Author: Skal ([email protected])

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "src/enc/cost_enc.h"
#include "src/enc/vp8i_enc.h"
#include "src/utils/utils.h"

#if !defined(DISABLE_TOKEN_BUFFER)

// we use pages to reduce the number of memcpy()
#define MIN_PAGE_SIZE …
#define FIXED_PROBA_BIT …

token_t;  // bit #15: bit value
                           // bit #14: flags for constant proba or idx
                           // bits #0..13: slot or constant proba
struct VP8Tokens { … };
// Token data is located in memory just after the next_ field.
// This macro is used to return their address and hide the trick.
#define TOKEN_DATA(p) …

//------------------------------------------------------------------------------

void VP8TBufferInit(VP8TBuffer* const b, int page_size) { … }

void VP8TBufferClear(VP8TBuffer* const b) { … }

static int TBufferNewPage(VP8TBuffer* const b) { … }

//------------------------------------------------------------------------------

#define TOKEN_ID …

static WEBP_INLINE uint32_t AddToken(VP8TBuffer* const b, uint32_t bit,
                                     uint32_t proba_idx,
                                     proba_t* const stats) { … }

static WEBP_INLINE void AddConstantToken(VP8TBuffer* const b,
                                         uint32_t bit, uint32_t proba) { … }

int VP8RecordCoeffTokens(int ctx, const struct VP8Residual* const res,
                         VP8TBuffer* const tokens) { … }

#undef TOKEN_ID

//------------------------------------------------------------------------------
// Final coding pass, with known probabilities

int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,
                  const uint8_t* const probas, int final_pass) { … }

// Size estimation
size_t VP8EstimateTokenSize(VP8TBuffer* const b, const uint8_t* const probas) { … }

//------------------------------------------------------------------------------

#else     // DISABLE_TOKEN_BUFFER

void VP8TBufferInit(VP8TBuffer* const b, int page_size) {
  (void)b;
  (void)page_size;
}
void VP8TBufferClear(VP8TBuffer* const b) {
  (void)b;
}

#endif    // !DISABLE_TOKEN_BUFFER
godot/thirdparty/libwebp/src/enc/token_enc.c
