LibC: Add mktime().

Kernel/UnixTypes.h

@@ -253,7 +253,7 @@ struct sigaction {
 
 // FIXME: Support 64-bit offsets!
 typedef signed_dword off_t;
-typedef unsigned int time_t;
+typedef dword time_t;
 
 struct utimbuf {
     time_t actime;

Kernel/types.h

@@ -41,8 +41,6 @@ typedef word mode_t;
 typedef dword nlink_t;
 typedef dword blksize_t;
 typedef dword blkcnt_t;
-typedef dword time_t;
-typedef dword suseconds_t;
 
 struct FarPtr {
     dword offset { 0 };

LibC/time.cpp

@@ -27,39 +27,53 @@ char* ctime(const time_t*)
     return const_cast<char*>("ctime() not implemented");
 }
 
-inline bool is_leap_year(unsigned year)
+static inline bool __is_leap_year(int year)
 {
     return ((year % 4 == 0) && ((year % 100 != 0) || (year % 400) == 0));
 }
 
+static const int __days_per_month[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+static const int __seconds_per_day = 60 * 60 * 24;
+
 static void time_to_tm(struct tm* tm, time_t t)
 {
-    static const unsigned seconds_per_day = 60 * 60 * 24;
-    static const unsigned days_per_month[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
-    unsigned days = t / seconds_per_day;
-    unsigned rem = t % seconds_per_day;
-    tm->tm_sec = rem % 60;
-    rem /= 60;
-    tm->tm_min = rem % 60;
-    tm->tm_hour = rem / 60;
+    int days = t / __seconds_per_day;
+    int remaining = t % __seconds_per_day;
+    tm->tm_sec = remaining % 60;
+    remaining /= 60;
+    tm->tm_min = remaining % 60;
+    tm->tm_hour = remaining / 60;
     tm->tm_wday = (4 + days) % 7;
-    unsigned year;
-    for (year = 1970; days >= 365 + is_leap_year(year); ++year)
-        days -= 365 + is_leap_year(year);
+    int year;
+    for (year = 1970; days >= 365 + __is_leap_year(year); ++year)
+        days -= 365 + __is_leap_year(year);
     tm->tm_year = year - 1900;
     tm->tm_yday = days;
     tm->tm_mday = 1;
-    if (is_leap_year(year) && days == 59)
+    if (__is_leap_year(year) && days == 59)
         ++tm->tm_mday;
-    if (is_leap_year(year) && days >= 59)
+    if (__is_leap_year(year) && days >= 59)
         --days;
-    unsigned month;
-    for (month = 0; month < 11 && days >= days_per_month[month]; ++month)
-        days -= days_per_month[month];
+    int month;
+    for (month = 0; month < 11 && days >= __days_per_month[month]; ++month)
+        days -= __days_per_month[month];
     tm->tm_mon = month;
     tm->tm_mday += days;
 }
 
+time_t mktime(struct tm* tm)
+{
+    int days = 0;
+    int seconds = tm->tm_hour * 3600 + tm->tm_min * 60 + tm->tm_sec;
+    for (int year = 70; year < tm->tm_year; ++year)
+        days += 365 + __is_leap_year(1900 + year);
+    tm->tm_yday = tm->tm_mday - 1;
+    for (int month = 0; month < tm->tm_mon; ++month)
+        tm->tm_yday += __days_per_month[month];
+    days += tm->tm_yday;
+    return days * __seconds_per_day + seconds;
+}
+
 struct tm* localtime(const time_t* t)
 {
     if (!t)