| /* |
| * 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_ |