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_ADAPTER_H 18 #define AAUDIO_FIXED_BLOCK_ADAPTER_H 19 20 #include <stdio.h> 21 22 /** 23 * Interface for a class that needs fixed-size blocks. 24 */ 25 class FixedBlockProcessor { 26 public: 27 virtual ~FixedBlockProcessor() = default; 28 virtual int32_t onProcessFixedBlock(uint8_t *buffer, int32_t numBytes) = 0; 29 }; 30 31 /** 32 * Base class for a variable-to-fixed-size block adapter. 33 */ 34 class FixedBlockAdapter 35 { 36 public: FixedBlockAdapter(FixedBlockProcessor & fixedBlockProcessor)37 FixedBlockAdapter(FixedBlockProcessor &fixedBlockProcessor) 38 : mFixedBlockProcessor(fixedBlockProcessor) {} 39 40 virtual ~FixedBlockAdapter(); 41 42 /** 43 * Allocate internal resources needed for buffering data. 44 */ 45 virtual int32_t open(int32_t bytesPerFixedBlock); 46 47 /** 48 * Note that if the fixed-sized blocks must be aligned, then the variable-sized blocks 49 * must have the same alignment. 50 * For example, if the fixed-size blocks must be a multiple of 8, then the variable-sized 51 * blocks must also be a multiple of 8. 52 * 53 * @param buffer 54 * @param numBytes 55 * @return zero if OK or a non-zero code 56 */ 57 virtual int32_t processVariableBlock(uint8_t *buffer, int32_t numBytes) = 0; 58 59 /** 60 * Free internal resources. 61 */ 62 int32_t close(); 63 64 protected: 65 FixedBlockProcessor &mFixedBlockProcessor; 66 uint8_t *mStorage = nullptr; // Store data here while assembling buffers. 67 int32_t mSize = 0; // Size in bytes of the fixed size buffer. 68 int32_t mPosition = 0; // Offset of the last byte read or written. 69 }; 70 71 #endif /* AAUDIO_FIXED_BLOCK_ADAPTER_H */ 72