Rewrite MakeDay function from JS to C++.

src/runtime.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4912 matching lines @@
 static Object* Runtime_Math_tan(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
   Counters::math_tan.Increment();
 
   CONVERT_DOUBLE_CHECKED(x, args[0]);
   return TranscendentalCache::Get(TranscendentalCache::TAN, x);
 }
 
 
+static Object* Runtime_DateMakeDay(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 3);
+
+  CONVERT_SMI_CHECKED(year, args[0]);
+  CONVERT_SMI_CHECKED(month, args[1]);
+  CONVERT_SMI_CHECKED(date, args[2]);
+
+  static const int day_from_month[] = {0, 31, 59, 90, 120, 151,
+                                       181, 212, 243, 273, 304, 334};
+  static const int day_from_month_leap[] = {0, 31, 60, 91, 121, 152,
+                                            182, 213, 244, 274, 305, 335};
+
+  year += month / 12;
+  month %= 12;
+  if (month < 0) {
+    year--;
+    month += 12;
+  }
+
+  static const int base_day = 365*1970 + 1969/4 - 1969/100 + 1969/400;
+
+  int day_from_year = 365*year + (year - 1)/4 - (year - 1)/100 + (year - 1)/400 - base_day;

[Mads Ager (chromium), 2010/03/02 13:04:08]

Line too long, please reformat.  Also, please have a space around arithmetic
operations and use parenthesis to make the precedence explicit.

[Oleg Eterevsky, 2010/03/02 13:28:23]

I tried to reformat it to make it more readable, avoiding extra parentheses.
Hope, it's ok now.

On 2010/03/02 13:04:08, Mads Ager wrote:

+
+  if (year % 4 || (year % 100 == 0 && year % 400 != 0)) {
+    return Smi::FromInt(day_from_year + day_from_month[month] + date - 1);
+  } else {
+    return Smi::FromInt(day_from_year + day_from_month_leap[month] + date - 1);
+  }
+}
+
+
 static Object* Runtime_NewArgumentsFast(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 3);
 
   JSFunction* callee = JSFunction::cast(args[0]);
   Object** parameters = reinterpret_cast<Object**>(args[1]);
   const int length = Smi::cast(args[2])->value();
 
   Object* result = Heap::AllocateArgumentsObject(callee, length);
   if (result->IsFailure()) return result;
@@ skipping 3404 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal