76 lines
2.7 KiB
C
76 lines
2.7 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// A ring buffer to hold arbitrary data. Provides no thread safety. Unless
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// otherwise specified, functions return 0 on success and -1 on error.
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#ifndef WEBRTC_COMMON_AUDIO_RING_BUFFER_H_
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#define WEBRTC_COMMON_AUDIO_RING_BUFFER_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stddef.h> // size_t
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enum Wrap { SAME_WRAP, DIFF_WRAP };
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typedef struct RingBuffer {
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size_t read_pos;
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size_t write_pos;
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size_t element_count;
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size_t element_size;
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enum Wrap rw_wrap;
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char* data;
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} RingBuffer;
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// Creates and initializes the buffer. Returns NULL on failure.
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RingBuffer* WebRtc_CreateBuffer(size_t element_count, size_t element_size);
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void WebRtc_InitBuffer(RingBuffer* handle);
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void WebRtc_FreeBuffer(void* handle);
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// Reads data from the buffer. The |data_ptr| will point to the address where
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// it is located. If all |element_count| data are feasible to read without
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// buffer wrap around |data_ptr| will point to the location in the buffer.
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// Otherwise, the data will be copied to |data| (memory allocation done by the
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// user) and |data_ptr| points to the address of |data|. |data_ptr| is only
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// guaranteed to be valid until the next call to WebRtc_WriteBuffer().
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//
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// To force a copying to |data|, pass a NULL |data_ptr|.
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//
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// Returns number of elements read.
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size_t WebRtc_ReadBuffer(RingBuffer* handle,
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void** data_ptr,
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void* data,
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size_t element_count);
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// Writes |data| to buffer and returns the number of elements written.
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size_t WebRtc_WriteBuffer(RingBuffer* handle, const void* data,
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size_t element_count);
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// Moves the buffer read position and returns the number of elements moved.
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// Positive |element_count| moves the read position towards the write position,
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// that is, flushing the buffer. Negative |element_count| moves the read
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// position away from the the write position, that is, stuffing the buffer.
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// Returns number of elements moved.
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int WebRtc_MoveReadPtr(RingBuffer* handle, int element_count);
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// Returns number of available elements to read.
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size_t WebRtc_available_read(const RingBuffer* handle);
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// Returns number of available elements for write.
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size_t WebRtc_available_write(const RingBuffer* handle);
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#ifdef __cplusplus
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}
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#endif
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#endif // WEBRTC_COMMON_AUDIO_RING_BUFFER_H_
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