fixed multithread support in neko

std/haxe/io/FPHelper.hx

@@ -6,16 +6,20 @@ package haxe.io;
 **/
 class FPHelper {
 
-	#if !(java || cs)
+	#if neko_v21
+	// stored in helper
+	#elseif neko
+	static var i64tmp = new neko.vm.Tls<Int64>();
+	#elseif !(java || cs)
 	static var i64tmp = Int64.ofInt(0);
 	#end
 
 	#if neko
 		#if neko_v21
-		static var helper = neko.NativeArray.alloc(2);
+		static var helpers = new neko.vm.Tls<neko.NativeArray<Dynamic>>();
 		#else
-		static var helperf = neko.NativeString.alloc(4);
-		static var helperd = neko.NativeString.alloc(8);
+		static var helperf = new neko.vm.Tls<neko.NativeString>();
+		static var helperd = new neko.vm.Tls<neko.NativeString>();
 		static var _float_of_bytes = neko.Lib.load("std","float_of_bytes",2);
 		static var _double_of_bytes = neko.Lib.load("std","double_of_bytes",2);
 		static var _float_bytes = neko.Lib.load("std","float_bytes",2);
@@ -45,7 +49,9 @@ class FPHelper {
 			#if neko_v21
 			return untyped $itof(i);
 			#else
-			var helper = helperf;
+			var helper = helperf.value;
+			if( helper == null )
+				helperf.value = helper = neko.NativeString.alloc(4);
 			untyped $sset(helper,0,i&0xFF);
 			untyped $sset(helper,1,(i>>8)&0xFF);
 			untyped $sset(helper,2,(i>>16)&0xFF);
@@ -138,7 +144,9 @@ class FPHelper {
 			#if neko_v21
 			return untyped $itod(low,high);
 			#else
-			var helper = helperd;
+			var helper = helperd.value;
+			if( helper == null )
+				helperd.value = helper = neko.NativeString.alloc(8);
 			untyped $sset(helper,0,low&0xFF);
 			untyped $sset(helper,1,(low>>8)&0xFF);
 			untyped $sset(helper,2,(low>>16)&0xFF);
@@ -198,20 +206,28 @@ class FPHelper {
 	/**
 		Returns an Int64 representing the bytes representation of the double precision IEEE float value.
 		WARNING : for performance reason, the same Int64 value might be reused every time. Copy its low/high values before calling again.
+		We still ensure that this is safe to use in a multithread environment
 	**/
-	#if neko_v21 inline #end
 	public static function doubleToI64( v : Float ) : Int64 {
 		#if neko
 			#if neko_v21
-			var helper = helper, i64 = i64tmp;
-			untyped $dtoi(v,helper);
+			var helper = helpers.value;
+			if( helper == null ) {
+				helpers.value = helper = neko.NativeArray.alloc(2);
+				helper[0] = neko.NativeArray.alloc(2);
+				helper[1] = haxe.Int64.ofInt(0);
+			}
+			var i64 : haxe.Int64 = helper[1], int2 = helper[0];
+			untyped $dtoi(v,int2);
 			@:privateAccess {
-				i64.low = helper[0];
-				i64.high = helper[1];
+				i64.low = int2[0];
+				i64.high = int2[1];
 			}
 			return i64;
 			#else
-			var r = _double_bytes(v,false), i64 = i64tmp;
+			var r = _double_bytes(v,false), i64 = i64tmp.value;
+			if( i64 == null )
+				i64 = i64tmp.value = haxe.Int64.ofInt(0);
 			@:privateAccess {
 				i64.low = untyped $sget(r,0) | ($sget(r,1)<<8) | ($sget(r,2)<<16) | ($sget(r,3)<<24);
 				i64.high =  untyped $sget(r,4) | ($sget(r,5)<<8) | ($sget(r,6)<<16) | ($sget(r,7)<<24);