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