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_COMMON_AUDIO_RING_BUFFER_H_ 15 #define WEBRTC_COMMON_AUDIO_RING_BUFFER_H_ 16 17 #ifdef __cplusplus 18 extern "C" { 19 #endif 20 21 #include <stddef.h> // size_t 22 23 typedef struct RingBuffer RingBuffer; 24 25 // Creates and initializes the buffer. Returns NULL on failure. 26 RingBuffer* WebRtc_CreateBuffer(size_t element_count, size_t element_size); 27 void WebRtc_InitBuffer(RingBuffer* handle); 28 void WebRtc_FreeBuffer(void* handle); 29 30 // Reads data from the buffer. The |data_ptr| will point to the address where 31 // it is located. If all |element_count| data are feasible to read without 32 // buffer wrap around |data_ptr| will point to the location in the buffer. 33 // Otherwise, the data will be copied to |data| (memory allocation done by the 34 // user) and |data_ptr| points to the address of |data|. |data_ptr| is only 35 // guaranteed to be valid until the next call to WebRtc_WriteBuffer(). 36 // 37 // To force a copying to |data|, pass a NULL |data_ptr|. 38 // 39 // Returns number of elements read. 40 size_t WebRtc_ReadBuffer(RingBuffer* handle, 41 void** data_ptr, 42 void* data, 43 size_t element_count); 44 45 // Writes |data| to buffer and returns the number of elements written. 46 size_t WebRtc_WriteBuffer(RingBuffer* handle, const void* data, 47 size_t element_count); 48 49 // Moves the buffer read position and returns the number of elements moved. 50 // Positive |element_count| moves the read position towards the write position, 51 // that is, flushing the buffer. Negative |element_count| moves the read 52 // position away from the the write position, that is, stuffing the buffer. 53 // Returns number of elements moved. 54 int WebRtc_MoveReadPtr(RingBuffer* handle, int element_count); 55 56 // Returns number of available elements to read. 57 size_t WebRtc_available_read(const RingBuffer* handle); 58 59 // Returns number of available elements for write. 60 size_t WebRtc_available_write(const RingBuffer* handle); 61 62 #ifdef __cplusplus 63 } 64 #endif 65 66 #endif // WEBRTC_COMMON_AUDIO_RING_BUFFER_H_ 67
