Source/bmalloc/libpas/src/libpas/pas_epoch.c

/*
 * Copyright (c) 2019-2021 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "pas_config.h"

#if LIBPAS_ENABLED

#include "pas_epoch.h"

#include "pas_log.h"
#include "pas_monotonic_time.h"

uint64_t pas_current_epoch;
bool pas_epoch_is_counter = false;

uint64_t pas_get_epoch(void)
{
    static const bool verbose = false;
    static bool first = true;
    
    uint64_t result;
    
    if (pas_epoch_is_counter) {
        /* This is just for testing. */
        result = ++pas_current_epoch;
    } else
        result = pas_get_current_monotonic_time_nanoseconds();

    PAS_ASSERT(result >= PAS_EPOCH_MIN);
    PAS_ASSERT(result <= PAS_EPOCH_MAX);

    if (first) {
        if (verbose)
            pas_log("first epoch = %llu\n", result);
        first = false;
    }

    return result;
}

#endif /* LIBPAS_ENABLED */