| 1 | /** @file
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| 2 | * IPRT - Lock Free Circular Buffer
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| 3 | */
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| 4 |
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| 5 | /*
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| 6 | * Copyright (C) 2010 Oracle Corporation
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| 7 | *
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| 8 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 9 | * available from http://www.virtualbox.org. This file is free software;
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| 10 | * you can redistribute it and/or modify it under the terms of the GNU
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| 11 | * General Public License (GPL) as published by the Free Software
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| 12 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 13 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 14 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 15 | *
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| 16 | * The contents of this file may alternatively be used under the terms
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| 17 | * of the Common Development and Distribution License Version 1.0
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| 18 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 19 | * VirtualBox OSE distribution, in which case the provisions of the
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| 20 | * CDDL are applicable instead of those of the GPL.
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| 21 | *
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| 22 | * You may elect to license modified versions of this file under the
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| 23 | * terms and conditions of either the GPL or the CDDL or both.
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| 24 | */
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| 25 |
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| 26 | #ifndef ___iprt_circbuf_h
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| 27 | #define ___iprt_circbuf_h
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| 28 |
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| 29 | #include <iprt/types.h>
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| 30 |
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| 31 | /** @defgroup grp_rt_circbuf RTCircBuf - Lock Free Circular Buffer
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| 32 | * @ingroup grp_rt
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| 33 | *
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| 34 | * Implementation of a lock free circular buffer which could be used in a multi
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| 35 | * threaded environment. Note that only the acquire, release and getter
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| 36 | * functions are threading aware. So don't use reset if the circular buffer is
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| 37 | * still in use.
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| 38 | *
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| 39 | * @{
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| 40 | */
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| 41 |
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| 42 | RT_C_DECLS_BEGIN
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| 43 |
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| 44 | /** Pointer to a circular buffer (abstract). */
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| 45 | typedef struct RTCIRCBUF *PRTCIRCBUF;
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| 46 |
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| 47 | /**
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| 48 | * Create a circular buffer.
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| 49 | *
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| 50 | * @returns IPRT status code.
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| 51 | *
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| 52 | * @param ppBuf Where to store the buffer.
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| 53 | * @param cbSize The size of the new buffer.
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| 54 | */
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| 55 | RTDECL(int) RTCircBufCreate(PRTCIRCBUF *ppBuf, size_t cbSize);
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| 56 |
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| 57 | /**
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| 58 | * Destroy the circular buffer.
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| 59 | *
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| 60 | * @param pBuf The buffer to destroy. NULL is ignored.
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| 61 | */
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| 62 | RTDECL(void) RTCircBufDestroy(PRTCIRCBUF pBuf);
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| 63 |
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| 64 | /**
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| 65 | * Reset all position information in the circular buffer.
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| 66 | *
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| 67 | * @note This function is not multi threading aware.
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| 68 | *
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| 69 | * @param pBuf The buffer to reset.
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| 70 | */
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| 71 | RTDECL(void) RTCircBufReset(PRTCIRCBUF pBuf);
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| 72 |
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| 73 | /**
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| 74 | * Returns the current free space of the buffer.
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| 75 | *
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| 76 | * @param pBuf The buffer to query.
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| 77 | */
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| 78 | RTDECL(size_t) RTCircBufFree(PRTCIRCBUF pBuf);
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| 79 |
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| 80 | /**
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| 81 | * Returns the current used space of the buffer.
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| 82 | *
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| 83 | * @param pBuf The buffer to query.
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| 84 | */
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| 85 | RTDECL(size_t) RTCircBufUsed(PRTCIRCBUF pBuf);
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| 86 |
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| 87 | /**
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| 88 | * Returns the size of the buffer.
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| 89 | *
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| 90 | * @param pBuf The buffer to query.
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| 91 | */
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| 92 | RTDECL(size_t) RTCircBufSize(PRTCIRCBUF pBuf);
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| 93 |
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| 94 | RTDECL(bool) RTCircBufIsReading(PRTCIRCBUF pBuf);
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| 95 | RTDECL(bool) RTCircBufIsWriting(PRTCIRCBUF pBuf);
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| 96 |
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| 97 | /**
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| 98 | * Acquire a block of the circular buffer for reading.
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| 99 | *
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| 100 | * @param pBuf The buffer to acquire from.
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| 101 | * @param cbReqSize The requested size of the block.
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| 102 | * @param ppvStart The resulting memory pointer.
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| 103 | * @param pcbSize The resulting size of the memory pointer.
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| 104 | */
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| 105 | RTDECL(void) RTCircBufAcquireReadBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
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| 106 |
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| 107 | /**
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| 108 | * Release a block which was acquired by RTCircBufAcquireReadBlock.
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| 109 | *
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| 110 | * @param pBuf The buffer to acquire from.
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| 111 | * @param cbSize The size of the block.
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| 112 | */
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| 113 | RTDECL(void) RTCircBufReleaseReadBlock(PRTCIRCBUF pBuf, size_t cbSize);
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| 114 |
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| 115 | /**
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| 116 | * Acquire a block of the circular buffer for writing.
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| 117 | *
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| 118 | * @param pBuf The buffer to acquire from.
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| 119 | * @param cbReqSize The requested size of the block.
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| 120 | * @param ppvStart The resulting memory pointer.
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| 121 | * @param pcbSize The resulting size of the memory pointer.
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| 122 | */
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| 123 | RTDECL(void) RTCircBufAcquireWriteBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
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| 124 |
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| 125 | /**
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| 126 | * Release a block which was acquired by RTCircBufAcquireWriteBlock.
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| 127 | *
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| 128 | * @param pBuf The buffer to acquire from.
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| 129 | * @param cbSize The size of the block.
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| 130 | */
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| 131 | RTDECL(void) RTCircBufReleaseWriteBlock(PRTCIRCBUF pBuf, size_t cbSize);
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| 132 |
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| 133 | RT_C_DECLS_END
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| 134 |
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| 135 | /** @} */
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| 136 |
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| 137 | #endif /* !___iprt_circbuf_h */
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| 138 |
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