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/*
* Copyright 2019 The libgav1 Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LIBGAV1_SRC_UTILS_BIT_READER_H_
#define LIBGAV1_SRC_UTILS_BIT_READER_H_
#include <cstdint>
namespace libgav1 {
class BitReader {
public:
virtual ~BitReader() = default;
virtual int ReadBit() = 0;
// |num_bits| has to be <= 32. The function returns a value in the range [0,
// 2^num_bits - 1] (inclusive) on success and -1 on failure.
virtual int64_t ReadLiteral(int num_bits) = 0;
bool DecodeSignedSubexpWithReference(int low, int high, int reference,
int control, int* value); // 5.9.26.
// Decodes a nonnegative integer with maximum number of values |n| (i.e.,
// output in range 0..n-1) by following the process specified in Section
// 4.10.7 ns(n) and Section 4.10.10 NS(n) of the spec.
bool DecodeUniform(int n, int* value);
private:
// Helper functions for DecodeSignedSubexpWithReference.
bool DecodeUnsignedSubexpWithReference(int mx, int reference, int control,
int* value); // 5.9.27.
bool DecodeSubexp(int num_symbols, int control, int* value); // 5.9.28.
};
} // namespace libgav1
#endif // LIBGAV1_SRC_UTILS_BIT_READER_H_
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