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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#ifndef LIB_JXL_ENTROPY_CODER_H_
#define LIB_JXL_ENTROPY_CODER_H_
#include <stddef.h>
#include <stdint.h>
#include "lib/jxl/ac_context.h"
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/dec_bit_reader.h"
#include "lib/jxl/field_encodings.h"
// Entropy coding and context modeling of DC and AC coefficients, as well as AC
// strategy and quantization field.
namespace jxl {
static JXL_INLINE int32_t PredictFromTopAndLeft(
const int32_t* const JXL_RESTRICT row_top,
const int32_t* const JXL_RESTRICT row, size_t x, int32_t default_val) {
if (x == 0) {
return row_top == nullptr ? default_val : row_top[x];
}
if (row_top == nullptr) {
return row[x - 1];
}
return (row_top[x] + row[x - 1] + 1) / 2;
}
static constexpr U32Enc kDCThresholdDist(Bits(4), BitsOffset(8, 16),
BitsOffset(16, 272),
BitsOffset(32, 65808));
static constexpr U32Enc kQFThresholdDist(Bits(2), BitsOffset(3, 4),
BitsOffset(5, 12), BitsOffset(8, 44));
Status DecodeBlockCtxMap(BitReader* br, BlockCtxMap* block_ctx_map);
} // namespace jxl
#endif // LIB_JXL_ENTROPY_CODER_H_
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