diff options
author | sanine <sanine.not@pm.me> | 2022-08-25 14:54:53 -0500 |
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committer | sanine <sanine.not@pm.me> | 2022-08-25 14:54:53 -0500 |
commit | 37c97e345d12f95dde44e1d1a4c2f2aadd4615bc (patch) | |
tree | e1bb25bc855883062bdd7847ff2c04290f71c840 /portaudio/src/common/pa_ringbuffer.h | |
parent | 5634c7b04da619669f2f29f6798c03982be05180 (diff) |
add initial structure
Diffstat (limited to 'portaudio/src/common/pa_ringbuffer.h')
-rw-r--r-- | portaudio/src/common/pa_ringbuffer.h | 236 |
1 files changed, 236 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..400aaac --- /dev/null +++ b/portaudio/src/common/pa_ringbuffer.h @@ -0,0 +1,236 @@ +#ifndef PA_RINGBUFFER_H +#define PA_RINGBUFFER_H +/* + * $Id$ + * 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. + * modified for multiple-byte-sized data elements by Sven Fischer + * + * 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 + @brief Single-reader single-writer lock-free ring buffer + + PaUtilRingBuffer is a ring buffer used to transport samples between + different execution contexts (threads, OS callbacks, interrupt handlers) + without requiring the use of any locks. This only works when there is + a single reader and a single writer (ie. one thread or callback writes + to the ring buffer, another thread or callback reads from it). + + The PaUtilRingBuffer structure manages a ring buffer containing N + elements, where N must be a power of two. An element may be any size + (specified in bytes). + + The memory area used to store the buffer elements must be allocated by + the client prior to calling PaUtil_InitializeRingBuffer() and must outlive + the use of the ring buffer. + + @note The ring buffer functions are not normally exposed in the PortAudio libraries. + If you want to call them then you will need to add pa_ringbuffer.c to your application source code. +*/ + +#if defined(__APPLE__) +#include <sys/types.h> +typedef int32_t ring_buffer_size_t; +#elif defined( __GNUC__ ) +typedef long ring_buffer_size_t; +#elif (_MSC_VER >= 1400) +typedef long ring_buffer_size_t; +#elif defined(_MSC_VER) || defined(__BORLANDC__) +typedef long ring_buffer_size_t; +#else +typedef long ring_buffer_size_t; +#endif + + + +#ifdef __cplusplus +extern "C" +{ +#endif /* __cplusplus */ + +typedef struct PaUtilRingBuffer +{ + ring_buffer_size_t bufferSize; /**< Number of elements in FIFO. Power of 2. Set by PaUtil_InitRingBuffer. */ + volatile ring_buffer_size_t writeIndex; /**< Index of next writable element. Set by PaUtil_AdvanceRingBufferWriteIndex. */ + volatile ring_buffer_size_t readIndex; /**< Index of next readable element. Set by PaUtil_AdvanceRingBufferReadIndex. */ + ring_buffer_size_t bigMask; /**< Used for wrapping indices with extra bit to distinguish full/empty. */ + ring_buffer_size_t smallMask; /**< Used for fitting indices to buffer. */ + ring_buffer_size_t elementSizeBytes; /**< Number of bytes per element. */ + char *buffer; /**< Pointer to the buffer containing the actual data. */ +}PaUtilRingBuffer; + +/** Initialize Ring Buffer to empty state ready to have elements written to it. + + @param rbuf The ring buffer. + + @param elementSizeBytes The size of a single data element in bytes. + + @param elementCount The number of elements in the buffer (must be a power of 2). + + @param dataPtr A pointer to a previously allocated area where the data + will be maintained. It must be elementCount*elementSizeBytes long. + + @return -1 if elementCount is not a power of 2, otherwise 0. +*/ +ring_buffer_size_t PaUtil_InitializeRingBuffer( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementSizeBytes, ring_buffer_size_t elementCount, void *dataPtr ); + +/** Reset buffer to empty. Should only be called when buffer is NOT being read or written. + + @param rbuf The ring buffer. +*/ +void PaUtil_FlushRingBuffer( PaUtilRingBuffer *rbuf ); + +/** Retrieve the number of elements available in the ring buffer for writing. + + @param rbuf The ring buffer. + + @return The number of elements available for writing. +*/ +ring_buffer_size_t PaUtil_GetRingBufferWriteAvailable( const PaUtilRingBuffer *rbuf ); + +/** Retrieve the number of elements available in the ring buffer for reading. + + @param rbuf The ring buffer. + + @return The number of elements available for reading. +*/ +ring_buffer_size_t PaUtil_GetRingBufferReadAvailable( const 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 elementCount The number of elements to be written. + + @return The number of elements written. +*/ +ring_buffer_size_t PaUtil_WriteRingBuffer( PaUtilRingBuffer *rbuf, const void *data, ring_buffer_size_t elementCount ); + +/** Read data from the ring buffer. + + @param rbuf The ring buffer. + + @param data The address where the data should be stored. + + @param elementCount The number of elements to be read. + + @return The number of elements read. +*/ +ring_buffer_size_t PaUtil_ReadRingBuffer( PaUtilRingBuffer *rbuf, void *data, ring_buffer_size_t elementCount ); + +/** Get address of region(s) to which we can write data. + + @param rbuf The ring buffer. + + @param elementCount The number of elements 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 elementCount. + + @param sizePtr2 The address where the second region length will be stored if + the first region is too small to satisfy elementCount. + + @return The room available to be written or elementCount, whichever is smaller. +*/ +ring_buffer_size_t PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount, + void **dataPtr1, ring_buffer_size_t *sizePtr1, + void **dataPtr2, ring_buffer_size_t *sizePtr2 ); + +/** Advance the write index to the next location to be written. + + @param rbuf The ring buffer. + + @param elementCount The number of elements to advance. + + @return The new position. +*/ +ring_buffer_size_t PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount ); + +/** Get address of region(s) from which we can read data. + + @param rbuf The ring buffer. + + @param elementCount The number of elements 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 elementCount. + + @param sizePtr2 The address where the second region length will be stored if + the first region is too small to satisfy elementCount. + + @return The number of elements available for reading. +*/ +ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount, + void **dataPtr1, ring_buffer_size_t *sizePtr1, + void **dataPtr2, ring_buffer_size_t *sizePtr2 ); + +/** Advance the read index to the next location to be read. + + @param rbuf The ring buffer. + + @param elementCount The number of elements to advance. + + @return The new position. +*/ +ring_buffer_size_t PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount ); + +#ifdef __cplusplus +} +#endif /* __cplusplus */ +#endif /* PA_RINGBUFFER_H */ |