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Diffstat (limited to '')
| -rw-r--r-- | include/iprt/circbuf.h | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/include/iprt/circbuf.h b/include/iprt/circbuf.h new file mode 100644 index 00000000..17d01451 --- /dev/null +++ b/include/iprt/circbuf.h @@ -0,0 +1,155 @@ +/** @file + * IPRT - Lock Free Circular Buffer + */ + +/* + * Copyright (C) 2010-2019 Oracle Corporation + * + * This file is part of VirtualBox Open Source Edition (OSE), as + * available from http://www.virtualbox.org. This file is free software; + * you can redistribute it and/or modify it under the terms of the GNU + * General Public License (GPL) as published by the Free Software + * Foundation, in version 2 as it comes in the "COPYING" file of the + * VirtualBox OSE distribution. VirtualBox OSE is distributed in the + * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + +#ifndef IPRT_INCLUDED_circbuf_h +#define IPRT_INCLUDED_circbuf_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/types.h> + +/** @defgroup grp_rt_circbuf RTCircBuf - Lock Free Circular Buffer + * @ingroup grp_rt + * + * Implementation of a lock free circular buffer which could be used in a multi + * threaded environment. Note that only the acquire, release and getter + * functions are threading aware. So don't use reset if the circular buffer is + * still in use. + * + * @{ + */ + +RT_C_DECLS_BEGIN + +/** Pointer to a circular buffer (abstract). */ +typedef struct RTCIRCBUF *PRTCIRCBUF; + +/** + * Create a circular buffer. + * + * @returns IPRT status code. + * + * @param ppBuf Where to store the buffer. + * @param cbSize The size of the new buffer. + */ +RTDECL(int) RTCircBufCreate(PRTCIRCBUF *ppBuf, size_t cbSize); + +/** + * Destroy the circular buffer. + * + * @param pBuf The buffer to destroy. NULL is ignored. + */ +RTDECL(void) RTCircBufDestroy(PRTCIRCBUF pBuf); + +/** + * Reset all position information in the circular buffer. + * + * @note This function is not multi threading aware. + * + * @param pBuf The buffer to reset. + */ +RTDECL(void) RTCircBufReset(PRTCIRCBUF pBuf); + +/** + * Returns the current free space of the buffer. + * + * @param pBuf The buffer to query. + */ +RTDECL(size_t) RTCircBufFree(PRTCIRCBUF pBuf); + +/** + * Returns the current used space of the buffer. + * + * @param pBuf The buffer to query. + */ +RTDECL(size_t) RTCircBufUsed(PRTCIRCBUF pBuf); + +/** + * Returns the size of the buffer. + * + * @param pBuf The buffer to query. + */ +RTDECL(size_t) RTCircBufSize(PRTCIRCBUF pBuf); + +RTDECL(bool) RTCircBufIsReading(PRTCIRCBUF pBuf); +RTDECL(bool) RTCircBufIsWriting(PRTCIRCBUF pBuf); + +/** + * Returns the current read offset (in bytes) within the buffer. + * + * @param pBuf The buffer to query. + */ +RTDECL(size_t) RTCircBufOffsetRead(PRTCIRCBUF pBuf); + +/** + * Returns the current write offset (in bytes) within the buffer. + * + * @param pBuf The buffer to query. + */ +RTDECL(size_t) RTCircBufOffsetWrite(PRTCIRCBUF pBuf); + +/** + * Acquire a block of the circular buffer for reading. + * + * @param pBuf The buffer to acquire from. + * @param cbReqSize The requested size of the block. + * @param ppvStart The resulting memory pointer. + * @param pcbSize The resulting size of the memory pointer. + */ +RTDECL(void) RTCircBufAcquireReadBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize); + +/** + * Release a block which was acquired by RTCircBufAcquireReadBlock. + * + * @param pBuf The buffer to acquire from. + * @param cbSize The size of the block. + */ +RTDECL(void) RTCircBufReleaseReadBlock(PRTCIRCBUF pBuf, size_t cbSize); + +/** + * Acquire a block of the circular buffer for writing. + * + * @param pBuf The buffer to acquire from. + * @param cbReqSize The requested size of the block. + * @param ppvStart The resulting memory pointer. + * @param pcbSize The resulting size of the memory pointer. + */ +RTDECL(void) RTCircBufAcquireWriteBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize); + +/** + * Release a block which was acquired by RTCircBufAcquireWriteBlock. + * + * @param pBuf The buffer to acquire from. + * @param cbSize The size of the block. + */ +RTDECL(void) RTCircBufReleaseWriteBlock(PRTCIRCBUF pBuf, size_t cbSize); + +RT_C_DECLS_END + +/** @} */ + +#endif /* !IPRT_INCLUDED_circbuf_h */ + |