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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.
#include "lib/jxl/entropy_coder.h"
#include <jxl/memory_manager.h>
#include <cstdint>
#include <vector>
#include "lib/jxl/ac_context.h"
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/status.h"
#include "lib/jxl/coeff_order.h"
#include "lib/jxl/coeff_order_fwd.h"
#include "lib/jxl/dec_bit_reader.h"
#include "lib/jxl/dec_context_map.h"
#include "lib/jxl/fields.h"
#include "lib/jxl/pack_signed.h"
namespace jxl {
Status DecodeBlockCtxMap(JxlMemoryManager* memory_manager, BitReader* br,
BlockCtxMap* block_ctx_map) {
auto& dct = block_ctx_map->dc_thresholds;
auto& qft = block_ctx_map->qf_thresholds;
auto& ctx_map = block_ctx_map->ctx_map;
bool is_default = static_cast<bool>(br->ReadFixedBits<1>());
if (is_default) {
*block_ctx_map = BlockCtxMap();
return true;
}
block_ctx_map->num_dc_ctxs = 1;
for (int j : {0, 1, 2}) {
dct[j].resize(br->ReadFixedBits<4>());
block_ctx_map->num_dc_ctxs *= dct[j].size() + 1;
for (int& i : dct[j]) {
i = UnpackSigned(U32Coder::Read(kDCThresholdDist, br));
}
}
qft.resize(br->ReadFixedBits<4>());
for (uint32_t& i : qft) {
i = U32Coder::Read(kQFThresholdDist, br) + 1;
}
if (block_ctx_map->num_dc_ctxs * (qft.size() + 1) > 64) {
return JXL_FAILURE("Invalid block context map: too big");
}
ctx_map.resize(3 * kNumOrders * block_ctx_map->num_dc_ctxs *
(qft.size() + 1));
JXL_RETURN_IF_ERROR(
DecodeContextMap(memory_manager, &ctx_map, &block_ctx_map->num_ctxs, br));
if (block_ctx_map->num_ctxs > 16) {
return JXL_FAILURE("Invalid block context map: too many distinct contexts");
}
return true;
}
#if JXL_CXX_LANG < JXL_CXX_17
constexpr uint8_t BlockCtxMap::kDefaultCtxMap[]; // from ac_context.h
#endif
} // namespace jxl