RTC_convert.c

1 files changed, 164 insertions, 0 deletions

diff --git a/arm9/lib/src/RTC_convert.c b/arm9/lib/src/RTC_convert.c
new file mode 100644
index 00000000..af5574dc
--- /dev/null
+++ b/arm9/lib/src/RTC_convert.c
@@ -0,0 +1,164 @@
+#include "global.h"
+#include "RTC_api.h"
+#include "RTC_convert.h"
+
+static s32 sDayOfYear[12] = {
+      0, // Jan
+     31, // Feb
+     59, // Mar
+     90, // Apr
+    120, // May
+    151, // Jun
+    181, // Jul
+    212, // Aug
+    243, // Sep
+    273, // Oct
+    304, // Nov
+    334, // Dec
+};
+
+static inline BOOL RTCi_IsLeapYear(u32 year)
+{
+    return !((year & 0x03));
+}
+
+s32 RTC_ConvertDateToDay(const RTCDate * date)
+{
+    if (date->year >= 100
+     || date->month < 1
+     || date->month > 12
+     || date->day < 1
+     || date->day > 31
+     || date->week >= RTC_WEEK_MAX
+     || date->month < 1   // can't be
+     || date->month > 12  // too sure
+    )
+        return -1;
+    s32 dayNum = (s32)(date->day - 1);
+    dayNum += sDayOfYear[date->month - 1];
+    if (date->month >= 3 && RTCi_IsLeapYear(date->year))
+        dayNum++;
+    dayNum += date->year * 365;
+    dayNum += (date->year + 3) / 4;
+    return dayNum;
+}
+
+s32 RTCi_ConvertTimeToSecond(const RTCTime * time)
+{
+    return (time->hour * 60 + time->minute) * 60 + time->second;
+}
+
+s64 RTC_ConvertDateTimeToSecond(const RTCDate * date, const RTCTime * time)
+{
+    s32 day = RTC_ConvertDateToDay(date);
+    if (day == -1)
+        return -1;
+    s32 second = RTCi_ConvertTimeToSecond(time);
+    if (second == -1)
+        return -1;
+    return ((s64)day) * (60 * 60 * 24) + second;
+}
+
+void RTC_ConvertDayToDate(RTCDate * date, s32 day)
+{
+    u32 year;
+    s32 month;
+
+    if (day < 0)
+    {
+        day = 0;
+    }
+    if (day > 36524) // max number of days that can be recorded
+    {
+        day = 36524;
+    }
+    date->week = (RTCWeek)((day + 6) % 7);
+    for (year = 0; year < 99; year++)
+    {
+        s32 prev = day;
+        day -= (RTCi_IsLeapYear(year)) ? 366 : 365;
+        if (day < 0)
+        {
+            day = prev;
+            break;
+        }
+    }
+    if (day > 365)
+    {
+        day = 365;
+    }
+    date->year = year;
+    if (RTCi_IsLeapYear(year))
+    {
+        if (day < 31 + 29)
+        {
+            if (day < 31)
+            {
+                month = 1;
+            }
+            else
+            {
+                month = 2;
+                day -= 31;
+            }
+            date->month = (u32)month;
+            date->day = (u32)(day + 1);
+            return;
+        }
+        else
+        {
+            day--;
+        }
+    }
+    for (month = 11; month >= 0; month--)
+    {
+        if (day >= sDayOfYear[month])
+        {
+            date->month = (u32)(month + 1);
+            date->day = (u32)(day - sDayOfYear[month] + 1);
+            return;
+        }
+    }
+    // Internal Error.
+}
+
+void RTCi_ConvertSecondToTime(RTCTime * time, s32 sec)
+{
+    if (sec < 0)
+        sec = 0;
+    if (sec > 86399)
+        sec = 86399;
+    time->second = (u32)(sec % 60);
+    sec /= 60;
+    time->minute = (u32)(sec % 60);
+    sec /= 60;
+    time->hour = (u32)sec;
+}
+
+void RTC_ConvertSecondToDateTime(RTCDate * date, RTCTime * time, s64 sec)
+{
+    if (sec < 0)
+        sec = 0;
+    else if (sec > 3155759999)
+        sec = 3155759999;
+    RTCi_ConvertSecondToTime(time, (s32)(sec % 86400));
+    RTC_ConvertDayToDate(date, (s32)(sec / 86400));
+}
+
+RTCWeek RTC_GetDayOfWeek(RTCDate * date)
+{
+    int cent;
+    int year = (int)(2000 + date->year);
+    int month = (int)date->month;
+    int day = (int)date->day;
+
+    month -= 2;
+    if (month < 1)
+    {
+        month += 12;
+        --year;
+    }
+    cent = year / 100;
+    year %= 100;
+    return (RTCWeek)(((26 * month - 2) / 10 + day + year + year / 4 + cent / 4 + 5 * cent) % 7);
+}