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 }