[33286] | 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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[98103] | 6 | * Copyright (C) 2010-2023 Oracle and/or its affiliates.
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[33286] | 7 | *
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[96407] | 8 | * This file is part of VirtualBox base platform packages, as
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| 9 | * available from https://www.virtualbox.org.
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[33286] | 10 | *
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[96407] | 11 | * This program is free software; you can redistribute it and/or
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| 12 | * modify it under the terms of the GNU General Public License
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| 13 | * as published by the Free Software Foundation, in version 3 of the
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| 14 | * License.
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| 15 | *
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| 16 | * This program is distributed in the hope that it will be useful, but
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| 17 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 19 | * General Public License for more details.
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| 20 | *
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| 21 | * You should have received a copy of the GNU General Public License
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| 22 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 23 | *
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[33286] | 24 | * The contents of this file may alternatively be used under the terms
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| 25 | * of the Common Development and Distribution License Version 1.0
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[96407] | 26 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 27 | * in the VirtualBox distribution, in which case the provisions of the
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[33286] | 28 | * CDDL are applicable instead of those of the GPL.
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| 29 | *
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| 30 | * You may elect to license modified versions of this file under the
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| 31 | * terms and conditions of either the GPL or the CDDL or both.
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[96407] | 32 | *
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| 33 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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[33286] | 34 | */
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| 35 |
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[76557] | 36 | #ifndef IPRT_INCLUDED_circbuf_h
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| 37 | #define IPRT_INCLUDED_circbuf_h
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[76507] | 38 | #ifndef RT_WITHOUT_PRAGMA_ONCE
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| 39 | # pragma once
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| 40 | #endif
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[33286] | 41 |
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| 42 | #include <iprt/types.h>
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| 43 |
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| 44 | /** @defgroup grp_rt_circbuf RTCircBuf - Lock Free Circular Buffer
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| 45 | * @ingroup grp_rt
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| 46 | *
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| 47 | * Implementation of a lock free circular buffer which could be used in a multi
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| 48 | * threaded environment. Note that only the acquire, release and getter
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| 49 | * functions are threading aware. So don't use reset if the circular buffer is
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| 50 | * still in use.
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| 51 | *
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| 52 | * @{
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| 53 | */
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| 54 |
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| 55 | RT_C_DECLS_BEGIN
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| 56 |
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[37210] | 57 | /** Pointer to a circular buffer (abstract). */
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| 58 | typedef struct RTCIRCBUF *PRTCIRCBUF;
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[33286] | 59 |
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| 60 | /**
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| 61 | * Create a circular buffer.
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| 62 | *
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| 63 | * @returns IPRT status code.
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| 64 | *
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| 65 | * @param ppBuf Where to store the buffer.
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| 66 | * @param cbSize The size of the new buffer.
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| 67 | */
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| 68 | RTDECL(int) RTCircBufCreate(PRTCIRCBUF *ppBuf, size_t cbSize);
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| 69 |
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| 70 | /**
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| 71 | * Destroy the circular buffer.
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| 72 | *
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[37208] | 73 | * @param pBuf The buffer to destroy. NULL is ignored.
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[33286] | 74 | */
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| 75 | RTDECL(void) RTCircBufDestroy(PRTCIRCBUF pBuf);
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| 76 |
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| 77 | /**
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| 78 | * Reset all position information in the circular buffer.
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| 79 | *
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[33291] | 80 | * @note This function is not multi threading aware.
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[33286] | 81 | *
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| 82 | * @param pBuf The buffer to reset.
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| 83 | */
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| 84 | RTDECL(void) RTCircBufReset(PRTCIRCBUF pBuf);
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| 85 |
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| 86 | /**
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| 87 | * Returns the current free space of the buffer.
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| 88 | *
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| 89 | * @param pBuf The buffer to query.
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| 90 | */
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| 91 | RTDECL(size_t) RTCircBufFree(PRTCIRCBUF pBuf);
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| 92 |
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| 93 | /**
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| 94 | * Returns the current used space of the buffer.
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| 95 | *
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| 96 | * @param pBuf The buffer to query.
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| 97 | */
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| 98 | RTDECL(size_t) RTCircBufUsed(PRTCIRCBUF pBuf);
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| 99 |
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| 100 | /**
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| 101 | * Returns the size of the buffer.
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| 102 | *
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| 103 | * @param pBuf The buffer to query.
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| 104 | */
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| 105 | RTDECL(size_t) RTCircBufSize(PRTCIRCBUF pBuf);
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| 106 |
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[39350] | 107 | RTDECL(bool) RTCircBufIsReading(PRTCIRCBUF pBuf);
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| 108 | RTDECL(bool) RTCircBufIsWriting(PRTCIRCBUF pBuf);
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| 109 |
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[33286] | 110 | /**
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[67364] | 111 | * Returns the current read offset (in bytes) within the buffer.
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| 112 | *
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| 113 | * @param pBuf The buffer to query.
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| 114 | */
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| 115 | RTDECL(size_t) RTCircBufOffsetRead(PRTCIRCBUF pBuf);
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| 116 |
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| 117 | /**
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| 118 | * Returns the current write offset (in bytes) within the buffer.
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| 119 | *
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| 120 | * @param pBuf The buffer to query.
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| 121 | */
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| 122 | RTDECL(size_t) RTCircBufOffsetWrite(PRTCIRCBUF pBuf);
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| 123 |
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| 124 | /**
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[33286] | 125 | * Acquire a block of the circular buffer for reading.
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| 126 | *
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| 127 | * @param pBuf The buffer to acquire from.
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| 128 | * @param cbReqSize The requested size of the block.
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| 129 | * @param ppvStart The resulting memory pointer.
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| 130 | * @param pcbSize The resulting size of the memory pointer.
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| 131 | */
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| 132 | RTDECL(void) RTCircBufAcquireReadBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
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| 133 |
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| 134 | /**
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| 135 | * Release a block which was acquired by RTCircBufAcquireReadBlock.
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| 136 | *
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| 137 | * @param pBuf The buffer to acquire from.
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| 138 | * @param cbSize The size of the block.
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| 139 | */
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| 140 | RTDECL(void) RTCircBufReleaseReadBlock(PRTCIRCBUF pBuf, size_t cbSize);
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| 141 |
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| 142 | /**
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| 143 | * Acquire a block of the circular buffer for writing.
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| 144 | *
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| 145 | * @param pBuf The buffer to acquire from.
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| 146 | * @param cbReqSize The requested size of the block.
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| 147 | * @param ppvStart The resulting memory pointer.
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| 148 | * @param pcbSize The resulting size of the memory pointer.
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| 149 | */
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| 150 | RTDECL(void) RTCircBufAcquireWriteBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
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| 151 |
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| 152 | /**
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| 153 | * Release a block which was acquired by RTCircBufAcquireWriteBlock.
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| 154 | *
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| 155 | * @param pBuf The buffer to acquire from.
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| 156 | * @param cbSize The size of the block.
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| 157 | */
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| 158 | RTDECL(void) RTCircBufReleaseWriteBlock(PRTCIRCBUF pBuf, size_t cbSize);
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| 159 |
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| 160 | RT_C_DECLS_END
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| 161 |
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| 162 | /** @} */
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| 163 |
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[76585] | 164 | #endif /* !IPRT_INCLUDED_circbuf_h */
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[33286] | 165 |
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