00001 #ifndef _RINGBUFFER_H 00002 #define _RINGBUFFER_H 00003 #ifdef __cplusplus 00004 extern "C" 00005 { 00006 #endif /* __cplusplus */ 00007 00008 /* 00009 * $Id: ringbuffer.h 90 2002-01-22 00:51:49Z phil $ 00010 * ringbuffer.h 00011 * Ring Buffer utility.. 00012 * 00013 * Author: Phil Burk, http://www.softsynth.com 00014 * modified for SMP safety on OS X by Bjorn Roche. 00015 * also allowed for const where possible. 00016 * Note that this is safe only for a single-thread reader 00017 * and a single-thread writer. 00018 * 00019 * This program is distributed with the PortAudio Portable Audio Library. 00020 * For more information see: http://www.portaudio.com 00021 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk 00022 * 00023 * Permission is hereby granted, free of charge, to any person obtaining 00024 * a copy of this software and associated documentation files 00025 * (the "Software"), to deal in the Software without restriction, 00026 * including without limitation the rights to use, copy, modify, merge, 00027 * publish, distribute, sublicense, and/or sell copies of the Software, 00028 * and to permit persons to whom the Software is furnished to do so, 00029 * subject to the following conditions: 00030 * 00031 * The above copyright notice and this permission notice shall be 00032 * included in all copies or substantial portions of the Software. 00033 * 00034 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 00035 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 00036 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 00037 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 00038 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 00039 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 00040 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00041 */ 00042 00043 /* 00044 * The text above constitutes the entire PortAudio license; however, 00045 * the PortAudio community also makes the following non-binding requests: 00046 * 00047 * Any person wishing to distribute modifications to the Software is 00048 * requested to send the modifications to the original developer so that 00049 * they can be incorporated into the canonical version. It is also 00050 * requested that these non-binding requests be included along with the 00051 * license above. 00052 */ 00053 00059 #include <stdio.h> 00060 #include <stdlib.h> 00061 #include <math.h> 00062 #include "ringbuffer.h" 00063 #include <string.h> 00064 00065 typedef struct 00066 { 00067 long bufferSize; /* Number of bytes in FIFO. Power of 2. Set by RingBuffer_Init. */ 00068 long writeIndex; /* Index of next writable byte. Set by RingBuffer_AdvanceWriteIndex. */ 00069 long readIndex; /* Index of next readable byte. Set by RingBuffer_AdvanceReadIndex. */ 00070 long bigMask; /* Used for wrapping indices with extra bit to distinguish full/empty. */ 00071 long smallMask; /* Used for fitting indices to buffer. */ 00072 char * buffer; 00073 } 00074 RingBuffer; 00075 /* 00076 * Initialize Ring Buffer. 00077 * numBytes must be power of 2, returns -1 if not. 00078 */ 00079 long RingBuffer_Init( RingBuffer *rbuf, long numBytes, void *dataPtr ); 00080 00081 /* Clear buffer. Should only be called when buffer is NOT being read. */ 00082 void RingBuffer_Flush( RingBuffer *rbuf ); 00083 00084 /* Return number of bytes available for writing. */ 00085 long RingBuffer_GetWriteAvailable( RingBuffer *rbuf ); 00086 /* Return number of bytes available for read. */ 00087 long RingBuffer_GetReadAvailable( RingBuffer *rbuf ); 00088 /* Return bytes written. */ 00089 long RingBuffer_Write( RingBuffer *rbuf, const void *data, long numBytes ); 00090 /* Return bytes read. */ 00091 long RingBuffer_Read( RingBuffer *rbuf, void *data, long numBytes ); 00092 00093 /* Get address of region(s) to which we can write data. 00094 ** If the region is contiguous, size2 will be zero. 00095 ** If non-contiguous, size2 will be the size of second region. 00096 ** Returns room available to be written or numBytes, whichever is smaller. 00097 */ 00098 long RingBuffer_GetWriteRegions( RingBuffer *rbuf, long numBytes, 00099 void **dataPtr1, long *sizePtr1, 00100 void **dataPtr2, long *sizePtr2 ); 00101 long RingBuffer_AdvanceWriteIndex( RingBuffer *rbuf, long numBytes ); 00102 00103 /* Get address of region(s) from which we can read data. 00104 ** If the region is contiguous, size2 will be zero. 00105 ** If non-contiguous, size2 will be the size of second region. 00106 ** Returns room available to be written or numBytes, whichever is smaller. 00107 */ 00108 long RingBuffer_GetReadRegions( RingBuffer *rbuf, long numBytes, 00109 void **dataPtr1, long *sizePtr1, 00110 void **dataPtr2, long *sizePtr2 ); 00111 00112 long RingBuffer_AdvanceReadIndex( RingBuffer *rbuf, long numBytes ); 00113 00114 #ifdef __cplusplus 00115 } 00116 #endif /* __cplusplus */ 00117 #endif /* _RINGBUFFER_H */