Implement time conversion routines for Unix and XT epoch formats

xtoskrnl/includes/rtl.hh

@@ -22,6 +22,7 @@
 #include <rtl/sha1.hh>
 #include <rtl/slist.hh>
 #include <rtl/string.hh>
+#include <rtl/time.hh>
 #include <rtl/widestr.hh>
 
 #endif /* __XTOSKRNL_RTL_HH */

xtoskrnl/includes/rtl/time.hh

@@ -0,0 +1,36 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/includes/rtl/time.hh
+ * DESCRIPTION:     Time conversion support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#ifndef __XTOSKRNL_RTL_TIME_HH
+#define __XTOSKRNL_RTL_TIME_HH
+
+#include <xtos.hh>
+
+
+/* Runtime Library */
+namespace RTL
+{
+    class Time
+    {
+        private:
+            STATIC CUSHORT DaysInMonth[2][12];
+            STATIC CUSHORT DaysPrecedingMonth[2][12];
+
+        public:
+            STATIC XTAPI XTSTATUS TimeFieldsToUnixEpoch(IN PTIME_FIELDS TimeFields,
+                                                        OUT PLONGLONG UnixTime);
+            STATIC XTAPI XTSTATUS TimeFieldsToXtEpoch(IN PTIME_FIELDS TimeFields,
+                                                      OUT PLARGE_INTEGER XtTime);
+
+        private:
+            STATIC XTFASTCALL BOOLEAN LeapYear(SHORT Year);
+
+    };
+}
+
+#endif /* __XTOSKRNL_RTL_TIME_HH */

xtoskrnl/rtl/data.cc

@@ -11,3 +11,15 @@
 
 /* This is required for floating numbers to keep LLVM happy */
 XTCLINK INT _fltused = 0xFEEDBULL;
+
+/* Lookup table for days in a month, Index 0 is normal year, Index 1 is leap year */
+CUSHORT RTL::Time::DaysInMonth[2][12] = {
+    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
+};
+
+/* Lookup table for days preceding a month, Index 0 is normal year, Index 1 is leap year */
+CUSHORT RTL::Time::DaysPrecedingMonth[2][12] = {
+    {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
+    {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
+};

xtoskrnl/rtl/exports.cc

@@ -1033,6 +1033,52 @@ RtlTestBit(IN PRTL_BITMAP BitMap,
     return RTL::BitMap::TestBit(BitMap, Bit);
 }
 
+/**
+ * Converts a TIME_FIELDS calendar structure to a 64-bit Unix timestamp.
+ *
+ * @param TimeFields
+ *        Supplies a pointer to a fully populated TIME_FIELDS structure.
+ *
+ * @param UnixTime
+ *        Supplies a pointer to a 64-bit integer that receives the number of
+ *        seconds elapsed since January 1, 1970.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTCLINK
+XTAPI
+XTSTATUS
+RtlTimeFieldsToUnixEpoch(IN PTIME_FIELDS TimeFields,
+                         OUT PLONGLONG UnixTime)
+{
+    return RTL::Time::TimeFieldsToUnixEpoch(TimeFields, UnixTime);
+}
+
+/**
+ * Converts a TIME_FIELDS calendar structure to a 64-bit XT timestamp.
+ *
+ * @param TimeFields
+ *        Supplies a pointer to a fully populated TIME_FIELDS structure.
+ *
+ * @param Time
+ *        Supplies a pointer to variable that receives the converted time value in 100-nanosecond
+ *        intervals since January 1, 1601.
+ *
+ * @return This routine returns the status code.
+ *
+ * @since XT 1.0
+ */
+XTCLINK
+XTAPI
+XTSTATUS
+RtlTimeFieldsToXtEpoch(IN PTIME_FIELDS TimeFields,
+                       OUT PLARGE_INTEGER XtTime)
+{
+    return RTL::Time::TimeFieldsToXtEpoch(TimeFields, XtTime);
+}
+
 /**
  * Finds the next token in a NULL-terminated string.
  *

xtoskrnl/rtl/time.cc

@@ -0,0 +1,129 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/rtl/time.cc
+ * DESCRIPTION:     Time conversion support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/**
+ * Determines if a given year is a leap year in the Gregorian calendar.
+ *
+ * @param Year
+ *        Supplies the year to be checked.
+ *
+ * @return This routine returns TRUE if the year is a leap year, FALSE otherwise.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+BOOLEAN
+RTL::Time::LeapYear(SHORT Year)
+{
+    return ((Year % 4 == 0 && Year % 100 != 0) || (Year % 400 == 0)) ? TRUE : FALSE;
+}
+
+/**
+ * Converts a TIME_FIELDS calendar structure to a 64-bit Unix timestamp.
+ *
+ * @param TimeFields
+ *        Supplies a pointer to a fully populated TIME_FIELDS structure.
+ *
+ * @param UnixTime
+ *        Supplies a pointer to a 64-bit integer that receives the number of
+ *        seconds elapsed since January 1, 1970.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+RTL::Time::TimeFieldsToUnixEpoch(IN PTIME_FIELDS TimeFields,
+                                 OUT PLONGLONG UnixTime)
+{
+    LONGLONG TotalSeconds;
+    LARGE_INTEGER XtTime;
+    XTSTATUS Status;
+
+    /* Convert to XT Epoch */
+    Status = TimeFieldsToXtEpoch(TimeFields, &XtTime);
+    if(Status != STATUS_SUCCESS)
+    {
+        /* Failed to convert to XT Epoch, return error code */
+        return Status;
+    }
+
+    /* Convert 100-nanosecond intervals (TICKS) to whole seconds */
+    TotalSeconds = XtTime.QuadPart / TICKS_PER_SECOND;
+
+    /* Subtract the number of seconds between January 1, 1601 and January 1, 1970 */
+    *UnixTime = TotalSeconds - 11644473600LL;
+
+    /* Return success */
+    return STATUS_SUCCESS;
+}
+
+/**
+ * Converts a TIME_FIELDS calendar structure to a 64-bit XT timestamp.
+ *
+ * @param TimeFields
+ *        Supplies a pointer to a fully populated TIME_FIELDS structure.
+ *
+ * @param Time
+ *        Supplies a pointer to variable that receives the converted time value in 100-nanosecond
+ *        intervals since January 1, 1601.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+XTSTATUS
+RTL::Time::TimeFieldsToXtEpoch(IN PTIME_FIELDS TimeFields,
+                               OUT PLARGE_INTEGER XtTime)
+{
+    ULONG Leap, ElapsedYears, ElapsedDays;
+    ULONGLONG TotalSeconds;
+
+    /* Check leap year */
+    Leap = LeapYear(TimeFields->Year) ? 1 : 0;
+
+    /* Validate input data */
+    if(TimeFields->Hour < 0 || TimeFields->Hour > 23 ||
+       TimeFields->Minute < 0 || TimeFields->Minute > 59 ||
+       TimeFields->Second < 0 || TimeFields->Second > 59 ||
+       TimeFields->Milliseconds < 0 || TimeFields->Milliseconds > 999 ||
+       TimeFields->Year < 1601 || TimeFields->Year > 30827 ||
+       TimeFields->Month < 1 || TimeFields->Month > 12 ||
+       TimeFields->Day < 1 || TimeFields->Day > DaysInMonth[Leap][TimeFields->Month - 1])
+    {
+        /* Invalid input data, return error code */
+        return STATUS_INVALID_PARAMETER;
+    }
+
+    /* Calculate days elapsed in previous years */
+    ElapsedYears = (ULONG)(TimeFields->Year - 1601);
+    ElapsedDays = (ElapsedYears * 365) + (ElapsedYears / 4) - (ElapsedYears / 100) + (ElapsedYears / 400);
+
+    /* Add days elapsed in previous months of the current year */
+    ElapsedDays += DaysPrecedingMonth[Leap][TimeFields->Month - 1];
+
+    /* Add days elapsed in the current month */
+    ElapsedDays += (TimeFields->Day - 1);
+
+    /* Calculate a total number of seconds */
+    TotalSeconds = ((ULONGLONG)ElapsedDays * SECONDS_PER_DAY) +
+                   ((ULONGLONG)TimeFields->Hour * SECONDS_PER_HOUR) +
+                   ((ULONGLONG)TimeFields->Minute * SECONDS_PER_MINUTE) +
+                   (ULONGLONG)TimeFields->Second;
+
+    /* Convert to 100-ns intervals and slap milliseconds on top */
+    Time->QuadPart = (TotalSeconds * TICKS_PER_SECOND) + ((ULONGLONG)TimeFields->Milliseconds * TICKS_PER_MILLISECOND);
+
+    /* Return success */
+    return STATUS_SUCCESS;
+}

xtoskrnl/xtoskrnl.spec

@@ -90,6 +90,8 @@
 @ stdcall RtlStringLength(str long)
 @ stdcall RtlStringToWideString(wstr str long)
 @ stdcall RtlTestBit(ptr long)
+@ stdcall RtlTimeFieldsToUnixEpoch(ptr ptr)
+@ stdcall RtlTimeFieldsToXtEpoch(ptr ptr)
 @ stdcall RtlTokenizeString(str str str)
 @ stdcall RtlTokenizeWideString(wstr wstr wstr)
 @ stdcall RtlToLowerCharacter(long)