root/ext/date/lib/interval.c

DEFINITIONS

1. timelib_diff
2. timelib_add
3. timelib_sub

   1 /*
   2  * The MIT License (MIT)
   3  *
   4  * Copyright (c) 2015 Derick Rethans
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 
  25 #include "timelib.h"
  26 #include <math.h>
  27 
  28 timelib_rel_time *timelib_diff(timelib_time *one, timelib_time *two)
  29 {
  30         timelib_rel_time *rt;
  31         timelib_time *swp;
  32         timelib_sll dst_corr = 0 ,dst_h_corr = 0, dst_m_corr = 0;
  33         timelib_time one_backup, two_backup;
  34 
  35         rt = timelib_rel_time_ctor();
  36         rt->invert = 0;
  37         if (one->sse > two->sse) {
  38                 swp = two;
  39                 two = one;
  40                 one = swp;
  41                 rt->invert = 1;
  42         }
  43 
  44         /* Calculate correction for DST change over, but only if the TZ type is ID
  45          * and it's the same */
  46         if (one->zone_type == 3 && two->zone_type == 3
  47                 && (strcmp(one->tz_info->name, two->tz_info->name) == 0)
  48                 && (one->z != two->z))
  49         {
  50                 dst_corr = two->z - one->z;
  51                 dst_h_corr = dst_corr / 3600;
  52                 dst_m_corr = (dst_corr % 3600) / 60;
  53         }
  54 
  55         /* Save old TZ info */
  56         memcpy(&one_backup, one, sizeof(one_backup));
  57         memcpy(&two_backup, two, sizeof(two_backup));
  58 
  59     timelib_apply_localtime(one, 0);
  60     timelib_apply_localtime(two, 0);
  61 
  62         rt->y = two->y - one->y;
  63         rt->m = two->m - one->m;
  64         rt->d = two->d - one->d;
  65         rt->h = two->h - one->h;
  66         rt->i = two->i - one->i;
  67         rt->s = two->s - one->s;
  68         if (one_backup.dst == 0 && two_backup.dst == 1 && two->sse >= one->sse + 86400 - dst_corr) {
  69                 rt->h += dst_h_corr;
  70                 rt->i += dst_m_corr;
  71         }
  72 
  73         rt->days = fabs(floor((one->sse - two->sse - (dst_h_corr * 3600) - (dst_m_corr * 60)) / 86400));
  74 
  75         timelib_do_rel_normalize(rt->invert ? one : two, rt);
  76 
  77         /* We need to do this after normalisation otherwise we can't get "24H" */
  78         if (one_backup.dst == 1 && two_backup.dst == 0 && two->sse >= one->sse + 86400) {
  79                 if (two->sse < one->sse + 86400 - dst_corr) {
  80                         rt->d--;
  81                         rt->h = 24;
  82                 } else {
  83                         rt->h += dst_h_corr;
  84                         rt->i += dst_m_corr;
  85                 }
  86         }
  87 
  88         /* Restore old TZ info */
  89         memcpy(one, &one_backup, sizeof(one_backup));
  90         memcpy(two, &two_backup, sizeof(two_backup));
  91 
  92         return rt;
  93 }
  94 
  95 timelib_time *timelib_add(timelib_time *old_time, timelib_rel_time *interval)
  96 {
  97         int bias = 1;
  98         timelib_time *t = timelib_time_clone(old_time);
  99 
 100         if (interval->have_weekday_relative || interval->have_special_relative) {
 101                 memcpy(&t->relative, interval, sizeof(struct timelib_rel_time));
 102         } else {
 103                 if (interval->invert) {
 104                         bias = -1;
 105                 }
 106                 memset(&t->relative, 0, sizeof(struct timelib_rel_time));
 107                 t->relative.y = interval->y * bias;
 108                 t->relative.m = interval->m * bias;
 109                 t->relative.d = interval->d * bias;
 110                 t->relative.h = interval->h * bias;
 111                 t->relative.i = interval->i * bias;
 112                 t->relative.s = interval->s * bias;
 113         }
 114         t->have_relative = 1;
 115         t->sse_uptodate = 0;
 116 
 117         timelib_update_ts(t, NULL);
 118 
 119 //      printf("%lld %lld %d\n", old_time->dst, t->dst, (t->sse - old_time->sse));
 120         /* Adjust for backwards DST changeover */
 121         if (old_time->dst == 1 && t->dst == 0 && !interval->y && !interval->m && !interval->d) {
 122                 t->sse -= old_time->z;
 123                 t->sse += t->z;
 124         }
 125 
 126         timelib_update_from_sse(t);
 127         t->have_relative = 0;
 128 
 129         return t;
 130 }
 131 
 132 timelib_time *timelib_sub(timelib_time *old_time, timelib_rel_time *interval)
 133 {
 134         int bias = 1;
 135         timelib_time *t = timelib_time_clone(old_time);
 136 
 137         if (interval->invert) {
 138                 bias = -1;
 139         }
 140 
 141         memset(&t->relative, 0, sizeof(struct timelib_rel_time));
 142         t->relative.y = 0 - (interval->y * bias);
 143         t->relative.m = 0 - (interval->m * bias);
 144         t->relative.d = 0 - (interval->d * bias);
 145         t->relative.h = 0 - (interval->h * bias);
 146         t->relative.i = 0 - (interval->i * bias);
 147         t->relative.s = 0 - (interval->s * bias);
 148         t->have_relative = 1;
 149         t->sse_uptodate = 0;
 150 
 151         timelib_update_ts(t, NULL);
 152 
 153         /* Adjust for backwards DST changeover */
 154         if (old_time->dst == 1 && t->dst == 0 && !interval->y && !interval->m && !interval->d) {
 155                 t->sse -= old_time->z;
 156                 t->sse += t->z;
 157         }
 158         /* Adjust for forwards DST changeover */
 159         if (old_time->dst == 0 && t->dst == 1 && !interval->y && !interval->m && !interval->d ) {
 160                 t->sse -= old_time->z;
 161                 t->sse += t->z;
 162         }
 163 
 164         timelib_update_from_sse(t);
 165 
 166         t->have_relative = 0;
 167 
 168         return t;
 169 }