| /* |
| * 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. |
| */ |
| |
| #ifndef PAS_EPOCH_H |
| #define PAS_EPOCH_H |
| |
| #include "pas_utils.h" |
| |
| PAS_BEGIN_EXTERN_C; |
| |
| PAS_API extern bool pas_epoch_is_counter; |
| PAS_API extern uint64_t pas_current_epoch; |
| |
| #define PAS_EPOCH_INVALID 0 |
| #define PAS_EPOCH_MIN 1 |
| #define PAS_EPOCH_MAX UINT64_MAX |
| |
| /* This *may* simply return a new epoch each time you call it. Or it may return some coarser |
| notion of epoch. The only requirement is that it proceeds monotonically, and even that |
| requirement is a weak one - slight time travel is to be tolerated by callers. |
| |
| However: in reality this is monotonic time in nanoseconds. Lots of things are tuned for that |
| fact. |
| |
| It's just that for testing purposes, we sometimes turn it into a counter and change the tuning |
| accordingly. But that won't happen except in the tests that need it. */ |
| PAS_API uint64_t pas_get_epoch(void); |
| |
| PAS_END_EXTERN_C; |
| |
| #endif /* PAS_EPOCH_H */ |
| |
