Coverage Report

Created: 2024-05-21 06:26

/src/libjxl/lib/jxl/entropy_coder.cc
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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "lib/jxl/entropy_coder.h"
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#include <jxl/memory_manager.h>
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#include <cstdint>
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#include <vector>
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#include "lib/jxl/ac_context.h"
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#include "lib/jxl/base/status.h"
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#include "lib/jxl/coeff_order.h"
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#include "lib/jxl/coeff_order_fwd.h"
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#include "lib/jxl/dec_bit_reader.h"
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#include "lib/jxl/dec_context_map.h"
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#include "lib/jxl/fields.h"
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#include "lib/jxl/pack_signed.h"
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namespace jxl {
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Status DecodeBlockCtxMap(JxlMemoryManager* memory_manager, BitReader* br,
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                         BlockCtxMap* block_ctx_map) {
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  auto& dct = block_ctx_map->dc_thresholds;
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  auto& qft = block_ctx_map->qf_thresholds;
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  auto& ctx_map = block_ctx_map->ctx_map;
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  bool is_default = static_cast<bool>(br->ReadFixedBits<1>());
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  if (is_default) {
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    *block_ctx_map = BlockCtxMap();
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    return true;
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  }
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  block_ctx_map->num_dc_ctxs = 1;
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  for (int j : {0, 1, 2}) {
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    dct[j].resize(br->ReadFixedBits<4>());
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    block_ctx_map->num_dc_ctxs *= dct[j].size() + 1;
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    for (int& i : dct[j]) {
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      i = UnpackSigned(U32Coder::Read(kDCThresholdDist, br));
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    }
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  }
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  qft.resize(br->ReadFixedBits<4>());
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  for (uint32_t& i : qft) {
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    i = U32Coder::Read(kQFThresholdDist, br) + 1;
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  }
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  if (block_ctx_map->num_dc_ctxs * (qft.size() + 1) > 64) {
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    return JXL_FAILURE("Invalid block context map: too big");
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  }
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  ctx_map.resize(3 * kNumOrders * block_ctx_map->num_dc_ctxs *
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                 (qft.size() + 1));
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  JXL_RETURN_IF_ERROR(
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      DecodeContextMap(memory_manager, &ctx_map, &block_ctx_map->num_ctxs, br));
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  if (block_ctx_map->num_ctxs > 16) {
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    return JXL_FAILURE("Invalid block context map: too many distinct contexts");
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  }
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  return true;
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}
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constexpr uint8_t BlockCtxMap::kDefaultCtxMap[];  // from ac_context.h
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}  // namespace jxl