time.php

   1 <?php
   2
   3 # This program is in the public domain within the United States. Additionally,
   4 # we waive copyright and related rights in the work worldwide through the CC0
   5 # 1.0 Universal public domain dedication, which can be found at
   6 # http://creativecommons.org/publicdomain/zero/1.0/
   7
   8
   9 # This file contains functions to manipulate/calculate dates/times
  10
  11 # FIXME make it so you can call this with a string YYYY-MM-DD
  12 function ymd_to_days($year, $month, $day) {
  13         return (int)(mktime(12,0,0,$month,$day, $year, 0) / 86400);
  14 }
  15
  16 function days_to_ymd($days) {
  17         return explode('-', date('Y-n-j', $days * 86400 + 43200));
  18 }
  19
  20 function days_to_weekday_name($days) {
  21         $day_names = array('Thursday', 'Friday', 'Saturday', 'Sunday', 'Monday', 'Tuesday', 'Wednesday');
  22         return $day_names[$days % 7];
  23 }
  24
  25
  26 #function time_test() {
  27 #       for($i = 0; $i < 41 * 86400; $i += 86399) {
  28 #               echo "seconds: $i";
  29 #               $days = (int)($i / 86400);
  30 #               list($year, $month, $day) = days_to_ymd($days);
  31 #               echo ", days_to_ymd($days): $year-$month-$day";
  32 #               $days = ymd_to_days($year, $month, $day);
  33 #               echo ", ymd_to_days($year, $month, $day): $days\n<br>";
  34 #       }
  35 #}
  36
  37
  38 # pass anything, and get a valid date
  39 #
  40 # returns array($year, $month, $day)
  41 function clean_ymd($year, $month, $day) {
  42         $year = intval($year, 10);
  43         $month = intval($month, 10);
  44         $day = intval($day, 10);
  45
  46         if($year < 100) {
  47                 $year += 2000;
  48         }
  49         if($month < 1) {
  50                 $month = 1;
  51         } elseif($month > 12) {
  52                 $month = 12;
  53         }
  54         if($day < 1) {
  55                 $day = 1;
  56         } else {
  57                 $max = date('t', mktime(12, 0, 0, $month, 1, $year));
  58                 if($day > $max) {
  59                         $day = $max;
  60                 }
  61         }
  62
  63         return array($year, $month, $day);
  64 }
  65
  66 # pass date like 3/21/99
  67 # returns array(year, month, day)
  68 function mdy_clean($date) {
  69         $date = preg_replace('|[^0-9/-]|', '', $date);
  70         $date = preg_replace('|-|', '/', $date);
  71         $parts = explode('/', $date);
  72         switch(count($parts)) {
  73                 case 1:
  74                         $year = $parts[0];
  75                         if(strlen($year) == 0) {
  76                                 list($month, $day, $year) = explode('/', date('m/d/Y'));
  77                         } else {
  78                                 list($month, $day) = explode('/', date('m/d'));
  79                         }
  80                 break;
  81                 case 2:
  82                         list($month, $year) = $parts;
  83                         $year = date('d');
  84                 break;
  85                 default:
  86                         list($month, $day, $year) = $parts;
  87         }
  88
  89         return clean_ymd($year, $month, $day);
  90 }
  91
  92 # convert date string from mm/dd/yyyy to yyyy-mm-dd
  93 function mdy_to_ymd($date) {
  94         list($year, $month, $day) = mdy_clean($date);
  95         return sprintf('%04u-%02u-%02u', $year, $month, $day);
  96 }
  97
  98 # pass date like 2008-11-21
  99 # returns array(year, month, day)
 100 function ymd_clean($date) {
 101         $date = preg_replace('|[^0-9/-]|', '', $date);
 102         $date = preg_replace('|/|', '-', $date);
 103         $parts = explode('-', $date);
 104         switch(count($parts)) {
 105                 case 1:
 106                         $year = $parts[0];
 107                         if(strlen($year) == 0 || $year < 1971 || $year > 2050) {
 108                                 list($year, $month, $day) = explode('-', date('Y-m-d'));
 109                         } else {
 110                                 list($month, $day) = explode('-', date('m-d'));
 111                         }
 112                 break;
 113                 case 2:
 114                         list($year, $month) = $parts;
 115                         $year = date('d');
 116                 break;
 117                 default:
 118                         list($year, $month, $day) = $parts;
 119         }
 120
 121         return clean_ymd($year, $month, $day);
 122 }
 123
 124 # convert date string from yyyy-mm-dd to mm/dd/yyyy
 125 function ymd_to_mdy($str) {
 126         list($year, $month, $day) = ymd_clean($str);
 127         return sprintf('%02u/%02u/%04u', $month, $day, $year);
 128 }