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
19int WebRtc_CreateBuffer(void** handle,
20                        size_t element_count,
21                        size_t element_size);
22int WebRtc_InitBuffer(void* handle);
23int WebRtc_FreeBuffer(void* handle);
24
25// Reads data from the buffer. The |data_ptr| will point to the address where
26// it is located. If all |element_count| data are feasible to read without
27// buffer wrap around |data_ptr| will point to the location in the buffer.
28// Otherwise, the data will be copied to |data| (memory allocation done by the
29// user) and |data_ptr| points to the address of |data|. |data_ptr| is only
30// guaranteed to be valid until the next call to WebRtc_WriteBuffer().
31// Returns number of elements read.
32size_t WebRtc_ReadBuffer(void* handle,
33                         void** data_ptr,
34                         void* data,
35                         size_t element_count);
36
37// Writes |data| to buffer and returns the number of elements written.
38size_t WebRtc_WriteBuffer(void* handle, const void* data, size_t element_count);
39
40// Moves the buffer read position and returns the number of elements moved.
41// Positive |element_count| moves the read position towards the write position,
42// that is, flushing the buffer. Negative |element_count| moves the read
43// position away from the the write position, that is, stuffing the buffer.
44// Returns number of elements moved.
45int WebRtc_MoveReadPtr(void* handle, int element_count);
46
47// Returns number of available elements to read.
48size_t WebRtc_available_read(const void* handle);
49
50// Returns number of available elements for write.
51size_t WebRtc_available_write(const void* handle);
52
53#endif // WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_RING_BUFFER_H_
54