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Diffstat (limited to 'portaudio/src/common/pa_ringbuffer.h')
| -rw-r--r-- | portaudio/src/common/pa_ringbuffer.h | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/portaudio/src/common/pa_ringbuffer.h b/portaudio/src/common/pa_ringbuffer.h new file mode 100644 index 0000000..ee69d2e --- /dev/null +++ b/portaudio/src/common/pa_ringbuffer.h @@ -0,0 +1,198 @@ +#ifndef PA_RINGBUFFER_H +#define PA_RINGBUFFER_H +/* + * $Id: pa_ringbuffer.h,v 1.1 2010/11/04 20:43:52 rbd Exp $ + * Portable Audio I/O Library + * Ring Buffer utility. + * + * Author: Phil Burk, http://www.softsynth.com + * modified for SMP safety on OS X by Bjorn Roche. + * also allowed for const where possible. + * Note that this is safe only for a single-thread reader + * and a single-thread writer. + * + * This program is distributed with the PortAudio Portable Audio Library. + * For more information see: http://www.portaudio.com + * Copyright (c) 1999-2000 Ross Bencina and Phil Burk + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files + * (the "Software"), to deal in the Software without restriction, + * including without limitation the rights to use, copy, modify, merge, + * publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, + * subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +/* + * The text above constitutes the entire PortAudio license; however, + * the PortAudio community also makes the following non-binding requests: + * + * Any person wishing to distribute modifications to the Software is + * requested to send the modifications to the original developer so that + * they can be incorporated into the canonical version. It is also + * requested that these non-binding requests be included along with the + * license above. + */ + +/** @file + @ingroup common_src +*/ + +#ifdef __cplusplus +extern "C" +{ +#endif /* __cplusplus */ + +typedef struct PaUtilRingBuffer +{ + long bufferSize; /* Number of bytes in FIFO. Power of 2. Set by PaUtil_InitRingBuffer. */ + long writeIndex; /* Index of next writable byte. Set by PaUtil_AdvanceRingBufferWriteIndex. */ + long readIndex; /* Index of next readable byte. Set by PaUtil_AdvanceRingBufferReadIndex. */ + long bigMask; /* Used for wrapping indices with extra bit to distinguish full/empty. */ + long smallMask; /* Used for fitting indices to buffer. */ + char *buffer; +}PaUtilRingBuffer; + +/** Initialize Ring Buffer. + + @param rbuf The ring buffer. + + @param numBytes The number of bytes in the buffer and must be power of 2. + + @param dataPtr A pointer to a previously allocated area where the data + will be maintained. It must be numBytes long. + + @return -1 if numBytes is not a power of 2, otherwise 0. +*/ +long PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, long numBytes, void *dataPtr ); + +/** Clear buffer. Should only be called when buffer is NOT being read. + + @param rbuf The ring buffer. +*/ +void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf ); + +/** Retrieve the number of bytes available in the ring buffer for writing. + + @param rbuf The ring buffer. + + @return The number of bytes available for writing. +*/ +long PaUtil_GetRingBufferWriteAvailable( PaUtilRingBuffer *rbuf ); + +/** Retrieve the number of bytes available in the ring buffer for reading. + + @param rbuf The ring buffer. + + @return The number of bytes available for reading. +*/ +long PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf ); + +/** Write data to the ring buffer. + + @param rbuf The ring buffer. + + @param data The address of new data to write to the buffer. + + @param numBytes The number of bytes to be written. + + @return The number of bytes written. +*/ +long PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, long numBytes ); + +/** Read data from the ring buffer. + + @param rbuf The ring buffer. + + @param data The address where the data should be stored. + + @param numBytes The number of bytes to be read. + + @return The number of bytes read. +*/ +long PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, long numBytes ); + +/** Get address of region(s) to which we can write data. + + @param rbuf The ring buffer. + + @param numBytes The number of bytes desired. + + @param dataPtr1 The address where the first (or only) region pointer will be + stored. + + @param sizePtr1 The address where the first (or only) region length will be + stored. + + @param dataPtr2 The address where the second region pointer will be stored if + the first region is too small to satisfy numBytes. + + @param sizePtr2 The address where the second region length will be stored if + the first region is too small to satisfy numBytes. + + @return The room available to be written or numBytes, whichever is smaller. +*/ +long PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ); + +/** Advance the write index to the next location to be written. + + @param rbuf The ring buffer. + + @param numBytes The number of bytes to advance. + + @return The new position. +*/ +long PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, long numBytes ); + +/** Get address of region(s) from which we can write data. + + @param rbuf The ring buffer. + + @param numBytes The number of bytes desired. + + @param dataPtr1 The address where the first (or only) region pointer will be + stored. + + @param sizePtr1 The address where the first (or only) region length will be + stored. + + @param dataPtr2 The address where the second region pointer will be stored if + the first region is too small to satisfy numBytes. + + @param sizePtr2 The address where the second region length will be stored if + the first region is too small to satisfy numBytes. + + @return The number of bytes available for reading. +*/ +long PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, long numBytes, + void **dataPtr1, long *sizePtr1, + void **dataPtr2, long *sizePtr2 ); + +/** Advance the read index to the next location to be read. + + @param rbuf The ring buffer. + + @param numBytes The number of bytes to advance. + + @return The new position. +*/ +long PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, long numBytes ); + +#ifdef __cplusplus +} +#endif /* __cplusplus */ +#endif /* PA_RINGBUFFER_H */ |