root / lab4 / .minix-src / include / sys / clock.h @ 13
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| 1 | 13 | up20180614 | /* $NetBSD: clock.h,v 1.3 2014/11/17 17:11:29 christos Exp $ */
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| 2 | |||
| 3 | /*-
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| 4 | * Copyright (c) 1996 The NetBSD Foundation, Inc.
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| 5 | * All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to The NetBSD Foundation
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| 8 | * by Gordon W. Ross
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | *
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| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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| 29 | * POSSIBILITY OF SUCH DAMAGE.
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| 30 | */
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| 31 | |||
| 32 | #ifndef _SYS_CLOCK_H_
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| 33 | #define _SYS_CLOCK_H_
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| 34 | |||
| 35 | /* Some handy constants. */
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| 36 | #define SECS_PER_MINUTE 60 |
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| 37 | #define SECS_PER_HOUR 3600 |
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| 38 | #define SECS_PER_DAY 86400 |
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| 39 | #define DAYS_PER_COMMON_YEAR 365 |
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| 40 | #define DAYS_PER_LEAP_YEAR 366 |
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| 41 | #define SECS_PER_COMMON_YEAR (SECS_PER_DAY * DAYS_PER_COMMON_YEAR)
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| 42 | #define SECS_PER_LEAP_YEAR (SECS_PER_DAY * DAYS_PER_LEAP_YEAR)
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| 43 | |||
| 44 | /* Traditional POSIX base year */
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| 45 | #define POSIX_BASE_YEAR 1970 |
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| 46 | |||
| 47 | /* Some handy functions */
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| 48 | static inline int |
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| 49 | days_in_month(int m)
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| 50 | {
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| 51 | switch (m) {
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| 52 | case 2: |
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| 53 | return 28; |
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| 54 | case 4: case 6: case 9: case 11: |
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| 55 | return 30; |
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| 56 | case 1: case 3: case 5: case 7: case 8: case 10: case 12: |
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| 57 | return 31; |
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| 58 | default:
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| 59 | return -1; |
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| 60 | } |
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| 61 | } |
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| 62 | |||
| 63 | /*
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| 64 | * This inline avoids some unnecessary modulo operations
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| 65 | * as compared with the usual macro:
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| 66 | * ( ((year % 4) == 0 &&
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| 67 | * (year % 100) != 0) ||
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| 68 | * ((year % 400) == 0) )
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| 69 | * It is otherwise equivalent.
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| 70 | */
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| 71 | static inline int |
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| 72 | is_leap_year(uint64_t year) |
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| 73 | {
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| 74 | if ((year & 3) != 0) |
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| 75 | return 0; |
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| 76 | |||
| 77 | if (__predict_false((year % 100) != 0)) |
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| 78 | return 1; |
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| 79 | |||
| 80 | return __predict_false((year % 400) == 0); |
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| 81 | } |
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| 82 | |||
| 83 | static inline int |
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| 84 | days_per_year(uint64_t year) |
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| 85 | {
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| 86 | return is_leap_year(year) ? DAYS_PER_LEAP_YEAR : DAYS_PER_COMMON_YEAR;
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| 87 | } |
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| 88 | |||
| 89 | #endif /* _SYS_CLOCK_H_ */ |