ringbuffer.h

00001 /*
00002  * iaxclient: a cross-platform IAX softphone library
00003  *
00004  * Copyrights:
00005  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
00006  * Copyright (C) 2007, Wimba, Inc.
00007  *
00008  * Contributors:
00009  * <see below>
00010  * Peter Grayson <jpgrayson@gmail.com>
00011  *
00012  * This program is free software, distributed under the terms of
00013  * the GNU Lesser (Library) General Public License.
00014  */
00015 
00016 /*
00017  * Ring Buffer utility.
00018  *
00019  * Author: Phil Burk, http://www.softsynth.com
00020  * modified for SMP safety on OS X by Bjorn Roche.
00021  * also allowed for const where possible.
00022  * Note that this is safe only for a single-thread reader
00023  * and a single-thread writer.
00024  *
00025  * Originally distributed with the PortAudio Portable Audio Library.
00026  * For more information see: http://www.portaudio.com
00027  * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
00028  *
00029  * Permission is hereby granted, free of charge, to any person obtaining
00030  * a copy of this software and associated documentation files
00031  * (the "Software"), to deal in the Software without restriction,
00032  * including without limitation the rights to use, copy, modify, merge,
00033  * publish, distribute, sublicense, and/or sell copies of the Software,
00034  * and to permit persons to whom the Software is furnished to do so,
00035  * subject to the following conditions:
00036  *
00037  * The above copyright notice and this permission notice shall be
00038  * included in all copies or substantial portions of the Software.
00039  *
00040  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00041  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00042  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
00043  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
00044  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
00045  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00046  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00047  */
00048 
00049 /*
00050  * The text above constitutes the entire PortAudio license; however,
00051  * the PortAudio community also makes the following non-binding requests:
00052  *
00053  * Any person wishing to distribute modifications to the Software is
00054  * requested to send the modifications to the original developer so that
00055  * they can be incorporated into the canonical version. It is also
00056  * requested that these non-binding requests be included along with the
00057  * license above.
00058  */
00059 
00060 #ifndef RINGBUFFER_H
00061 #define RINGBUFFER_H
00062 
00063 #ifdef __cplusplus
00064 extern "C"
00065 {
00066 #endif /* __cplusplus */
00067 
00068 typedef struct rb_RingBuffer
00069 {
00070     long   bufferSize; /* Number of bytes in FIFO. Power of 2. Set by rb_InitializeRingBuffer. */
00071     long   writeIndex; /* Index of next writable byte. Set by rb_AdvanceRingBufferWriteIndex. */
00072     long   readIndex;  /* Index of next readable byte. Set by rb_AdvanceRingBufferReadIndex. */
00073     long   bigMask;    /* Used for wrapping indices with extra bit to distinguish full/empty. */
00074     long   smallMask;  /* Used for fitting indices to buffer. */
00075     char  *buffer;
00076 }rb_RingBuffer;
00077 
00089 long rb_InitializeRingBuffer( rb_RingBuffer *rbuf, long numBytes, void *dataPtr );
00090 
00095 void rb_FlushRingBuffer( rb_RingBuffer *rbuf );
00096 
00103 long rb_GetRingBufferWriteAvailable( rb_RingBuffer *rbuf );
00104 
00111 long rb_GetRingBufferReadAvailable( rb_RingBuffer *rbuf );
00112 
00123 long rb_WriteRingBuffer( rb_RingBuffer *rbuf, const void *data, long numBytes );
00124 
00135 long rb_ReadRingBuffer( rb_RingBuffer *rbuf, void *data, long numBytes );
00136 
00157 long rb_GetRingBufferWriteRegions( rb_RingBuffer *rbuf, long numBytes,
00158                                        void **dataPtr1, long *sizePtr1,
00159                                        void **dataPtr2, long *sizePtr2 );
00160 
00169 long rb_AdvanceRingBufferWriteIndex( rb_RingBuffer *rbuf, long numBytes );
00170 
00191 long rb_GetRingBufferReadRegions( rb_RingBuffer *rbuf, long numBytes,
00192                                       void **dataPtr1, long *sizePtr1,
00193                                       void **dataPtr2, long *sizePtr2 );
00194 
00203 long rb_AdvanceRingBufferReadIndex( rb_RingBuffer *rbuf, long numBytes );
00204 
00205 #ifdef __cplusplus
00206 }
00207 #endif /* __cplusplus */
00208 #endif /* RINGBUFFER_H */

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