1 /* 2 * Copyright (C) 2017 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 AAUDIO_FIXED_BLOCK_READER_H 18 #define AAUDIO_FIXED_BLOCK_READER_H 19 20 #include <stdint.h> 21 22 #include "FixedBlockAdapter.h" 23 24 /** 25 * Read from a fixed-size block to a variable sized block. 26 * 27 * This can be used to convert a pull data flow from fixed sized buffers to variable sized buffers. 28 * An example would be an audio output callback that reads from the app. 29 */ 30 class FixedBlockReader : public FixedBlockAdapter 31 { 32 public: 33 FixedBlockReader(FixedBlockProcessor &fixedBlockProcessor); 34 35 virtual ~FixedBlockReader() = default; 36 37 int32_t open(int32_t bytesPerFixedBlock) override; 38 39 /** 40 * Read into a variable sized block. 41 * 42 * Note that if the fixed-sized blocks must be aligned, then the variable-sized blocks 43 * must have the same alignment. 44 * For example, if the fixed-size blocks must be a multiple of 8, then the variable-sized 45 * blocks must also be a multiple of 8. 46 * 47 * @param buffer 48 * @param numBytes 49 * @return Number of bytes read or a negative error code. 50 */ 51 int32_t read(uint8_t *buffer, int32_t numBytes); 52 53 private: 54 int32_t readFromStorage(uint8_t *buffer, int32_t numBytes); 55 56 int32_t mValid = 0; // Number of valid bytes in mStorage. 57 }; 58 59 60 #endif /* AAUDIO_FIXED_BLOCK_READER_H */ 61