torsten
77c67c12ca
Entire-Metadata: .entire/metadata/fb87247f-2a75-407e-b336-cbc8c20ba5a6 Entire-Session: fb87247f-2a75-407e-b336-cbc8c20ba5a6 Entire-Strategy: manual-commit
82 lines
2.4 KiB
C
82 lines
2.4 KiB
C
/*
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* (c) Copyright, Real-Time Innovations, 2002-2016.
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* All rights reserved.
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* No duplications, whole or partial, manual or electronic, may be made
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* without express written permission. Any such copies, or
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* revisions thereof, must display this notice unaltered.
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* This code contains trade secrets of Real-Time Innovations, Inc.
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*/
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#ifndef reda_epoch_h
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#define reda_epoch_h
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#include "reda/reda_dll.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Doxygen file & module documentation ==================================*/
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/*e \file
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\brief Defines the REDAEpoch interface
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*/
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/*e \defgroup REDAEpochClass REDAEpoch
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\ingroup REDAModule
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\brief used to determine staleness, version counting, and central to
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lockless table.
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That is, multiple threads can concurrently write the epoch.
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Multiple concurrent readers will never see intermediate garbage values.
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We assume writing an "unsigned int" is atomic on all architectures for now.
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All weakly referenced information has an epoch which is strictly
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monotonically increasing with every change. If the referer finds that
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his idea of epoch is different than the current epoch, it means that
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his information is stale and therefore should not be used.
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*/
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/*e \ingroup REDAEpochClass
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@brief Definition of the type
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@todo consider making the epoch the LONGEST int that can be written
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atomically (e.g. long) on every platform
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*/
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typedef unsigned int REDAEpoch;
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/*e \ingroup REDAEpochClass
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@brief Unknown REDAEpoch
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Usually, when an epoch is unknown, the actor should assume the information
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tied to the unknown epoch is stale. Depending on the usage, it may also
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mean that the caller wants to find the correct latest epoch.
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*/
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#define REDA_EPOCH_UNKNOWN (0)
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/*i \ingroup REDAEpochClass
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For wrap detection.
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WARNING: ASSUMPTION: an unsigned int is at least 32 bits (it's OK
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if it's bigger).
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*/
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#define REDA_EPOCH_HALF_VALUE ((REDAEpoch) 0x80000000)
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/*e \ingroup REDAEpochClass
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Tests whether this epoch is greater than the value
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@return 1 if true, 0 otherwise
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*/
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extern REDADllExport int REDAEpoch_isGreater(REDAEpoch me, REDAEpoch value);
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/*e \ingroup REDAEpochClass
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Tests whether this epoch is less than the value
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@return 1 if true, 0 otherwise
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*/
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extern REDADllExport int REDAEpoch_isLess(REDAEpoch me, REDAEpoch value);
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#include "reda/reda_epoch_impl.h"
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#endif /* reda_epoch_h */
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