1/* 2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11// A ring buffer to hold arbitrary data. Provides no thread safety. Unless 12// otherwise specified, functions return 0 on success and -1 on error. 13 14#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_RING_BUFFER_H_ 15#define WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_RING_BUFFER_H_ 16 17#include <stddef.h> // size_t 18 19typedef struct RingBuffer RingBuffer; 20 21// Returns NULL on failure. 22RingBuffer* WebRtc_CreateBuffer(size_t element_count, size_t element_size); 23int WebRtc_InitBuffer(RingBuffer* handle); 24void WebRtc_FreeBuffer(void* handle); 25 26// Reads data from the buffer. The |data_ptr| will point to the address where 27// it is located. If all |element_count| data are feasible to read without 28// buffer wrap around |data_ptr| will point to the location in the buffer. 29// Otherwise, the data will be copied to |data| (memory allocation done by the 30// user) and |data_ptr| points to the address of |data|. |data_ptr| is only 31// guaranteed to be valid until the next call to WebRtc_WriteBuffer(). 32// 33// To force a copying to |data|, pass a NULL |data_ptr|. 34// 35// Returns number of elements read. 36size_t WebRtc_ReadBuffer(RingBuffer* handle, 37 void** data_ptr, 38 void* data, 39 size_t element_count); 40 41// Writes |data| to buffer and returns the number of elements written. 42size_t WebRtc_WriteBuffer(RingBuffer* handle, const void* data, 43 size_t element_count); 44 45// Moves the buffer read position and returns the number of elements moved. 46// Positive |element_count| moves the read position towards the write position, 47// that is, flushing the buffer. Negative |element_count| moves the read 48// position away from the the write position, that is, stuffing the buffer. 49// Returns number of elements moved. 50int WebRtc_MoveReadPtr(RingBuffer* handle, int element_count); 51 52// Returns number of available elements to read. 53size_t WebRtc_available_read(const RingBuffer* handle); 54 55// Returns number of available elements for write. 56size_t WebRtc_available_write(const RingBuffer* handle); 57 58#endif // WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_RING_BUFFER_H_ 59