source/common/monthviewgen.cpp

   1 // monthviewgen.cpp - Xestia Calendar month view generation functions.
   2 //
   3 // (c) 2016-2017 Xestia Software Development.
   4 //
   5 // This file is part of Xestia Calendar.
   6 //
   7 // Xestia Calendar is free software: you can redistribute it and/or modify
   8 // it under the terms of the GNU General Public License as published by the
   9 // Free Software Foundation, version 3 of the license.
  10 //
  11 // Xestia Calendar is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License along
  17 // with Xestia Calendar. If not, see <http://www.gnu.org/licenses/>
  18
  19 #include "monthviewgen.h"
  20
  21 using namespace std;
  22
  23 int PreviousMonthNumberofDays(int month, int year){
  24
  25         // Work out what the previous month is.
  26
  27         // Return 31 if month matches.
  28
  29         if (month == 1 || month == 2 || month == 4 ||
  30                 month == 6 || month == 8 || month == 9 || month == 11){
  31
  32                 return 31;
  33
  34         }
  35
  36         // Return 30 if month matches.
  37
  38         if (month == 5 || month == 7 || month == 10 || month == 12){
  39
  40                 return 30;
  41
  42         }
  43
  44         // Work out if year is a leap year and return 28 or 29
  45         // for february.
  46
  47         if (year % 4 == 0){
  48
  49                 if (year % 100 == 0){
  50
  51                         if (year % 400 == 0){
  52
  53                                 return 29;
  54
  55                         } else {
  56
  57                                 return 28;
  58
  59                         }
  60
  61                 }
  62
  63                 return 29;
  64
  65         } else {
  66
  67                 return 28;
  68
  69         }
  70
  71 }
  72
  73 XCCalendarMonthViewGrid GenerateMonthGrid(int month, int year){
  74
  75         XCCalendarMonthViewGrid monthViewOutput;
  76
  77         // Work out which day of the week the first day of
  78         // the month is.
  79
  80         time_t emptyTime;
  81         struct tm * firstDay;
  82         int previousMonthNumDays = PreviousMonthNumberofDays(month, year);
  83         int previousMonthDays = 0;
  84         int previousMonth = 0;
  85         int previousYear = year;
  86         int dayWeekCount = 0;
  87         bool processGrid = true;
  88         bool firstWeekProcessing = true;
  89
  90         time(&emptyTime);
  91
  92         firstDay = localtime(&emptyTime);
  93         firstDay->tm_year = year - 1900;
  94         firstDay->tm_mon = month - 1;
  95         firstDay->tm_mday = 1;
  96
  97         mktime(firstDay);
  98
  99         if (firstDay->tm_wday == 0){
 100                 previousMonthDays = 6;
 101         } else {
 102                 previousMonthDays = firstDay->tm_wday - 1;
 103         }
 104
 105         if (month == 1){
 106
 107                 previousMonth = 12;
 108                 previousYear--;
 109
 110         } else {
 111
 112                 previousMonth = month - 1;
 113
 114         }
 115
 116         // Workout the days of the previous month for the
 117         // first week to be displayed.
 118
 119         XCCalendarMonthViewGridDayWeek firstWeek;
 120
 121         for (int previousMonthDaysProcessing = 0;
 122                 previousMonthDaysProcessing < previousMonthDays;
 123                 previousMonthDaysProcessing++){
 124
 125                 XCCalendarMonthViewGridDayData dayItem;
 126
 127                 dayItem.day = previousMonthNumDays - previousMonthDaysProcessing;
 128                 dayItem.month = previousMonth;
 129                 dayItem.year = previousYear;
 130                 dayItem.isInMonth = false;
 131
 132                 firstWeek.dayList.insert(firstWeek.dayList.begin(), dayItem);
 133
 134                 dayWeekCount++;
 135
 136         }
 137
 138         // Process the actual days of the month.
 139
 140         XCCalendarMonthViewGridDayWeek monthWeek;
 141         int processDay = 1;
 142
 143         while (processGrid == true){
 144
 145                 if (dayWeekCount == 7){
 146
 147                         // Add to the month view grid.
 148
 149                         if (firstWeekProcessing == true){
 150
 151                                 firstWeekProcessing = false;
 152                                 monthViewOutput.weekList.push_back(firstWeek);
 153
 154                         } else {
 155
 156                                 monthViewOutput.weekList.push_back(monthWeek);
 157                                 monthWeek.dayList.clear();
 158
 159                         }
 160
 161                         dayWeekCount = 0;
 162                         continue;
 163
 164                 }
 165
 166                 XCCalendarMonthViewGridDayData dayItem;
 167
 168                 dayItem.day = processDay;
 169                 dayItem.month = month;
 170                 dayItem.year = year;
 171                 dayItem.isInMonth = true;
 172
 173                 if (firstWeekProcessing == true){
 174
 175                         firstWeek.dayList.push_back(dayItem);
 176
 177                 } else {
 178
 179                         monthWeek.dayList.push_back(dayItem);
 180
 181                 }
 182
 183                 dayWeekCount++;
 184
 185                 if ((month == 1 || month == 3 || month == 5 ||
 186                         month == 7 || month == 8 || month == 10 || month == 12) &&
 187                         processDay == 31){
 188
 189                         break;
 190
 191                 }
 192
 193                 if ((month == 4 || month == 6 || month == 9 || month == 11) &&
 194                         processDay == 30){
 195
 196                         break;
 197
 198                 }
 199
 200                 if (year % 4 == 0){
 201
 202                         if (year % 100 == 0){
 203
 204                                 if (year % 400 == 0){
 205
 206                                         if (month == 2 && processDay == 29){
 207
 208                                                 break;
 209
 210                                         }
 211
 212                                 } else {
 213
 214                                         if (month == 2 && processDay == 28){
 215
 216                                                 break;
 217
 218                                         }
 219
 220                                 }
 221
 222                         }
 223
 224                         if (month == 2 && processDay == 29){
 225
 226                                 break;
 227
 228                         }
 229
 230                 } else if ((month == 2 && processDay == 28) && year % 4 != 0){
 231
 232                         break;
 233
 234                 }
 235
 236                 processDay++;
 237
 238
 239         }
 240
 241         // At the end of the month add any remaining days
 242         // (if required).
 243
 244         int nextMonthYear = year;
 245         int nextMonth = 0;
 246         int nextMonthDay = 1;
 247
 248         if (month == 12){
 249
 250                 nextMonth = 1;
 251                 nextMonthYear++;
 252
 253         } else {
 254
 255                 nextMonth = month + 1;
 256
 257         }
 258
 259         for (; dayWeekCount < 7; dayWeekCount++){
 260
 261                 XCCalendarMonthViewGridDayData dayItem;
 262
 263                 dayItem.day = nextMonthDay;
 264                 dayItem.month = nextMonth;
 265                 dayItem.year = nextMonthYear;
 266                 dayItem.isInMonth = false;
 267
 268                 monthWeek.dayList.push_back(dayItem);
 269                 nextMonthDay++;
 270
 271         }
 272
 273         if (dayWeekCount == 7){
 274
 275                 monthViewOutput.weekList.push_back(monthWeek);
 276
 277         }
 278
 279         return monthViewOutput;
 280
 281 }