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source: webrtc/webrtc/modules/audio_device/mac/portaudio/pa_ringbuffer.c @ 0:4bda6873e34c

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Last change on this file since 0:4bda6873e34c was 0:4bda6873e34c, checked in by Michael Prittie <mprittie@…>, 6 years ago

Scrubbed password for publication.

File size: 9.1 KB
Line 
1/*
2 * $Id: pa_ringbuffer.c 1421 2009-11-18 16:09:05Z bjornroche $
3 * Portable Audio I/O Library
4 * Ring Buffer utility.
5 *
6 * Author: Phil Burk, http://www.softsynth.com
7 * modified for SMP safety on Mac OS X by Bjorn Roche
8 * modified for SMP safety on Linux by Leland Lucius
9 * also, allowed for const where possible
10 * modified for multiple-byte-sized data elements by Sven Fischer
11 *
12 * Note that this is safe only for a single-thread reader and a
13 * single-thread writer.
14 *
15 * This program uses the PortAudio Portable Audio Library.
16 * For more information see: http://www.portaudio.com
17 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
18 *
19 * Permission is hereby granted, free of charge, to any person obtaining
20 * a copy of this software and associated documentation files
21 * (the "Software"), to deal in the Software without restriction,
22 * including without limitation the rights to use, copy, modify, merge,
23 * publish, distribute, sublicense, and/or sell copies of the Software,
24 * and to permit persons to whom the Software is furnished to do so,
25 * subject to the following conditions:
26 *
27 * The above copyright notice and this permission notice shall be
28 * included in all copies or substantial portions of the Software.
29 *
30 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
31 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
32 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
33 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
34 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
35 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
36 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
37 */
38
39/*
40 * The text above constitutes the entire PortAudio license; however,
41 * the PortAudio community also makes the following non-binding requests:
42 *
43 * Any person wishing to distribute modifications to the Software is
44 * requested to send the modifications to the original developer so that
45 * they can be incorporated into the canonical version. It is also
46 * requested that these non-binding requests be included along with the
47 * license above.
48 */
49
50/**
51 @file
52 @ingroup common_src
53*/
54
55#include <math.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include "webrtc/modules/audio_device/mac/portaudio/pa_memorybarrier.h"
60#include "webrtc/modules/audio_device/mac/portaudio/pa_ringbuffer.h"
61
62/***************************************************************************
63 * Initialize FIFO.
64 * elementCount must be power of 2, returns -1 if not.
65 */
66ring_buffer_size_t PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementSizeBytes, ring_buffer_size_t elementCount, void *dataPtr )
67{
68    if( ((elementCount-1) & elementCount) != 0) return -1; /* Not Power of two. */
69    rbuf->bufferSize = elementCount;
70    rbuf->buffer = (char *)dataPtr;
71    PaUtil_FlushRingBuffer( rbuf );
72    rbuf->bigMask = (elementCount*2)-1;
73    rbuf->smallMask = (elementCount)-1;
74    rbuf->elementSizeBytes = elementSizeBytes;
75    return 0;
76}
77
78/***************************************************************************
79** Return number of elements available for reading. */
80ring_buffer_size_t PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf )
81{
82    PaUtil_ReadMemoryBarrier();
83    return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask );
84}
85/***************************************************************************
86** Return number of elements available for writing. */
87ring_buffer_size_t PaUtil_GetRingBufferWriteAvailable( PaUtilRingBuffer *rbuf )
88{
89    /* Since we are calling PaUtil_GetRingBufferReadAvailable, we don't need an aditional MB */
90    return ( rbuf->bufferSize - PaUtil_GetRingBufferReadAvailable(rbuf));
91}
92
93/***************************************************************************
94** Clear buffer. Should only be called when buffer is NOT being read. */
95void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf )
96{
97    rbuf->writeIndex = rbuf->readIndex = 0;
98}
99
100/***************************************************************************
101** Get address of region(s) to which we can write data.
102** If the region is contiguous, size2 will be zero.
103** If non-contiguous, size2 will be the size of second region.
104** Returns room available to be written or elementCount, whichever is smaller.
105*/
106ring_buffer_size_t PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount,
107                                       void **dataPtr1, ring_buffer_size_t *sizePtr1,
108                                       void **dataPtr2, ring_buffer_size_t *sizePtr2 )
109{
110    ring_buffer_size_t   index;
111    ring_buffer_size_t   available = PaUtil_GetRingBufferWriteAvailable( rbuf );
112    if( elementCount > available ) elementCount = available;
113    /* Check to see if write is not contiguous. */
114    index = rbuf->writeIndex & rbuf->smallMask;
115    if( (index + elementCount) > rbuf->bufferSize )
116    {
117        /* Write data in two blocks that wrap the buffer. */
118        ring_buffer_size_t   firstHalf = rbuf->bufferSize - index;
119        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
120        *sizePtr1 = firstHalf;
121        *dataPtr2 = &rbuf->buffer[0];
122        *sizePtr2 = elementCount - firstHalf;
123    }
124    else
125    {
126        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
127        *sizePtr1 = elementCount;
128        *dataPtr2 = NULL;
129        *sizePtr2 = 0;
130    }
131    return elementCount;
132}
133
134
135/***************************************************************************
136*/
137ring_buffer_size_t PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )
138{
139    /* we need to ensure that previous writes are seen before we update the write index */
140    PaUtil_WriteMemoryBarrier();
141    return rbuf->writeIndex = (rbuf->writeIndex + elementCount) & rbuf->bigMask;
142}
143
144/***************************************************************************
145** Get address of region(s) from which we can read data.
146** If the region is contiguous, size2 will be zero.
147** If non-contiguous, size2 will be the size of second region.
148** Returns room available to be written or elementCount, whichever is smaller.
149*/
150ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount,
151                                void **dataPtr1, ring_buffer_size_t *sizePtr1,
152                                void **dataPtr2, ring_buffer_size_t *sizePtr2 )
153{
154    ring_buffer_size_t   index;
155    ring_buffer_size_t   available = PaUtil_GetRingBufferReadAvailable( rbuf );
156    if( elementCount > available ) elementCount = available;
157    /* Check to see if read is not contiguous. */
158    index = rbuf->readIndex & rbuf->smallMask;
159    if( (index + elementCount) > rbuf->bufferSize )
160    {
161        /* Write data in two blocks that wrap the buffer. */
162        ring_buffer_size_t firstHalf = rbuf->bufferSize - index;
163        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
164        *sizePtr1 = firstHalf;
165        *dataPtr2 = &rbuf->buffer[0];
166        *sizePtr2 = elementCount - firstHalf;
167    }
168    else
169    {
170        *dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
171        *sizePtr1 = elementCount;
172        *dataPtr2 = NULL;
173        *sizePtr2 = 0;
174    }
175    return elementCount;
176}
177/***************************************************************************
178*/
179ring_buffer_size_t PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )
180{
181    /* we need to ensure that previous writes are always seen before updating the index. */
182    PaUtil_WriteMemoryBarrier();
183    return rbuf->readIndex = (rbuf->readIndex + elementCount) & rbuf->bigMask;
184}
185
186/***************************************************************************
187** Return elements written. */
188ring_buffer_size_t PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, ring_buffer_size_t elementCount )
189{
190    ring_buffer_size_t size1, size2, numWritten;
191    void *data1, *data2;
192    numWritten = PaUtil_GetRingBufferWriteRegions( rbuf, elementCount, &data1, &size1, &data2, &size2 );
193    if( size2 > 0 )
194    {
195
196        memcpy( data1, data, size1*rbuf->elementSizeBytes );
197        data = ((char *)data) + size1*rbuf->elementSizeBytes;
198        memcpy( data2, data, size2*rbuf->elementSizeBytes );
199    }
200    else
201    {
202        memcpy( data1, data, size1*rbuf->elementSizeBytes );
203    }
204    PaUtil_AdvanceRingBufferWriteIndex( rbuf, numWritten );
205    return numWritten;
206}
207
208/***************************************************************************
209** Return elements read. */
210ring_buffer_size_t PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, ring_buffer_size_t elementCount )
211{
212    ring_buffer_size_t size1, size2, numRead;
213    void *data1, *data2;
214    numRead = PaUtil_GetRingBufferReadRegions( rbuf, elementCount, &data1, &size1, &data2, &size2 );
215    if( size2 > 0 )
216    {
217        memcpy( data, data1, size1*rbuf->elementSizeBytes );
218        data = ((char *)data) + size1*rbuf->elementSizeBytes;
219        memcpy( data, data2, size2*rbuf->elementSizeBytes );
220    }
221    else
222    {
223        memcpy( data, data1, size1*rbuf->elementSizeBytes );
224    }
225    PaUtil_AdvanceRingBufferReadIndex( rbuf, numRead );
226    return numRead;
227}
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