VirtualBox

source: vbox/trunk/include/iprt/circbuf.h@ 103224

Last change on this file since 103224 was 98103, checked in by vboxsync, 21 months ago

Copyright year updates by scm.

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1/** @file
2 * IPRT - Lock Free Circular Buffer
3 */
4
5/*
6 * Copyright (C) 2010-2023 Oracle and/or its affiliates.
7 *
8 * This file is part of VirtualBox base platform packages, as
9 * available from https://www.virtualbox.org.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation, in version 3 of the
14 * License.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, see <https://www.gnu.org/licenses>.
23 *
24 * The contents of this file may alternatively be used under the terms
25 * of the Common Development and Distribution License Version 1.0
26 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
27 * in the VirtualBox distribution, in which case the provisions of the
28 * CDDL are applicable instead of those of the GPL.
29 *
30 * You may elect to license modified versions of this file under the
31 * terms and conditions of either the GPL or the CDDL or both.
32 *
33 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
34 */
35
36#ifndef IPRT_INCLUDED_circbuf_h
37#define IPRT_INCLUDED_circbuf_h
38#ifndef RT_WITHOUT_PRAGMA_ONCE
39# pragma once
40#endif
41
42#include <iprt/types.h>
43
44/** @defgroup grp_rt_circbuf RTCircBuf - Lock Free Circular Buffer
45 * @ingroup grp_rt
46 *
47 * Implementation of a lock free circular buffer which could be used in a multi
48 * threaded environment. Note that only the acquire, release and getter
49 * functions are threading aware. So don't use reset if the circular buffer is
50 * still in use.
51 *
52 * @{
53 */
54
55RT_C_DECLS_BEGIN
56
57/** Pointer to a circular buffer (abstract). */
58typedef struct RTCIRCBUF *PRTCIRCBUF;
59
60/**
61 * Create a circular buffer.
62 *
63 * @returns IPRT status code.
64 *
65 * @param ppBuf Where to store the buffer.
66 * @param cbSize The size of the new buffer.
67 */
68RTDECL(int) RTCircBufCreate(PRTCIRCBUF *ppBuf, size_t cbSize);
69
70/**
71 * Destroy the circular buffer.
72 *
73 * @param pBuf The buffer to destroy. NULL is ignored.
74 */
75RTDECL(void) RTCircBufDestroy(PRTCIRCBUF pBuf);
76
77/**
78 * Reset all position information in the circular buffer.
79 *
80 * @note This function is not multi threading aware.
81 *
82 * @param pBuf The buffer to reset.
83 */
84RTDECL(void) RTCircBufReset(PRTCIRCBUF pBuf);
85
86/**
87 * Returns the current free space of the buffer.
88 *
89 * @param pBuf The buffer to query.
90 */
91RTDECL(size_t) RTCircBufFree(PRTCIRCBUF pBuf);
92
93/**
94 * Returns the current used space of the buffer.
95 *
96 * @param pBuf The buffer to query.
97 */
98RTDECL(size_t) RTCircBufUsed(PRTCIRCBUF pBuf);
99
100/**
101 * Returns the size of the buffer.
102 *
103 * @param pBuf The buffer to query.
104 */
105RTDECL(size_t) RTCircBufSize(PRTCIRCBUF pBuf);
106
107RTDECL(bool) RTCircBufIsReading(PRTCIRCBUF pBuf);
108RTDECL(bool) RTCircBufIsWriting(PRTCIRCBUF pBuf);
109
110/**
111 * Returns the current read offset (in bytes) within the buffer.
112 *
113 * @param pBuf The buffer to query.
114 */
115RTDECL(size_t) RTCircBufOffsetRead(PRTCIRCBUF pBuf);
116
117/**
118 * Returns the current write offset (in bytes) within the buffer.
119 *
120 * @param pBuf The buffer to query.
121 */
122RTDECL(size_t) RTCircBufOffsetWrite(PRTCIRCBUF pBuf);
123
124/**
125 * Acquire a block of the circular buffer for reading.
126 *
127 * @param pBuf The buffer to acquire from.
128 * @param cbReqSize The requested size of the block.
129 * @param ppvStart The resulting memory pointer.
130 * @param pcbSize The resulting size of the memory pointer.
131 */
132RTDECL(void) RTCircBufAcquireReadBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
133
134/**
135 * Release a block which was acquired by RTCircBufAcquireReadBlock.
136 *
137 * @param pBuf The buffer to acquire from.
138 * @param cbSize The size of the block.
139 */
140RTDECL(void) RTCircBufReleaseReadBlock(PRTCIRCBUF pBuf, size_t cbSize);
141
142/**
143 * Acquire a block of the circular buffer for writing.
144 *
145 * @param pBuf The buffer to acquire from.
146 * @param cbReqSize The requested size of the block.
147 * @param ppvStart The resulting memory pointer.
148 * @param pcbSize The resulting size of the memory pointer.
149 */
150RTDECL(void) RTCircBufAcquireWriteBlock(PRTCIRCBUF pBuf, size_t cbReqSize, void **ppvStart, size_t *pcbSize);
151
152/**
153 * Release a block which was acquired by RTCircBufAcquireWriteBlock.
154 *
155 * @param pBuf The buffer to acquire from.
156 * @param cbSize The size of the block.
157 */
158RTDECL(void) RTCircBufReleaseWriteBlock(PRTCIRCBUF pBuf, size_t cbSize);
159
160RT_C_DECLS_END
161
162/** @} */
163
164#endif /* !IPRT_INCLUDED_circbuf_h */
165
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