1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef A_BIT_READER_H_ 18 19 #define A_BIT_READER_H_ 20 21 #include <media/stagefright/foundation/ABase.h> 22 23 #include <sys/types.h> 24 #include <stdint.h> 25 26 namespace android { 27 28 class ABitReader { 29 public: 30 ABitReader(const uint8_t *data, size_t size); 31 virtual ~ABitReader(); 32 33 uint32_t getBits(size_t n); 34 void skipBits(size_t n); 35 36 void putBits(uint32_t x, size_t n); 37 38 size_t numBitsLeft() const; 39 40 const uint8_t *data() const; 41 42 protected: 43 const uint8_t *mData; 44 size_t mSize; 45 46 uint32_t mReservoir; // left-aligned bits 47 size_t mNumBitsLeft; 48 49 virtual void fillReservoir(); 50 51 DISALLOW_EVIL_CONSTRUCTORS(ABitReader); 52 }; 53 54 class NALBitReader : public ABitReader { 55 public: 56 NALBitReader(const uint8_t *data, size_t size); 57 58 bool atLeastNumBitsLeft(size_t n) const; 59 60 private: 61 int32_t mNumZeros; 62 63 virtual void fillReservoir(); 64 65 DISALLOW_EVIL_CONSTRUCTORS(NALBitReader); 66 }; 67 68 } // namespace android 69 70 #endif // A_BIT_READER_H_ 71
