restore haxe.Utf8 and deprecate it

std/cpp/_std/haxe/Utf8.hx

@@ -24,6 +24,7 @@ package haxe;
 using cpp.NativeString;
 
 @:coreApi
+@:deprecate('haxe.Utf8 is deprecated. Use UnicodeString instead.')
 class Utf8
 {
    var __s:Array<Int>;

std/eval/_std/haxe/Utf8.hx

@@ -22,6 +22,7 @@
 package haxe;
 
 @:coreApi
+@:deprecate('haxe.Utf8 is deprecated. Use UnicodeString instead.')
 extern class Utf8 {
 	public function new( ?size : Int ):Void;
 	public function addChar( c : Int ) : Void;

std/haxe/Utf8.hx

@@ -25,6 +25,7 @@ package haxe;
 	Since not all platforms guarantee that `String` always uses UTF-8 encoding, you
 	can use this cross-platform API to perform operations on such strings.
 **/
+@:deprecate('haxe.Utf8 is deprecated. Use UnicodeString instead.')
 class Utf8 {
 
 	var __b : String;

std/neko/Utf8.hx

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C)2005-2019 Haxe Foundation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+package neko;
+
+@:coreApi
+class Utf8 {
+
+	var __b : Dynamic;
+
+	public function new( ?size : Int ) : Void {
+		__b = utf8_buf_alloc(if( size == null ) 1 else size);
+	}
+
+	public function addChar( c : Int ) : Void {
+		utf8_buf_add(__b,c);
+	}
+
+	public function toString() : String {
+		return new String(utf8_buf_content(__b));
+	}
+
+	public static function encode( s : String ) : String {
+		s = untyped s.__s;
+		var sl = untyped __dollar__ssize(s);
+		var buf:Dynamic = utf8_buf_alloc( sl );
+		var i = 0;
+		while( i < sl ) {
+			utf8_buf_add(buf,untyped __dollar__sget(s,i));
+			i += 1;
+		}
+		return new String( utf8_buf_content(buf) );
+	}
+
+	public static function decode( s : String ) : String {
+		s = untyped s.__s;
+		var sl = untyped __dollar__ssize(s);
+		var ret = untyped __dollar__smake(sl);
+		var i = 0;
+		utf8_iter(s,function(c) {
+			if( c == 8364 ) // euro symbol
+				c = 164;
+			else if( c == 0xFEFF ) // BOM
+				return;
+			else if( c > 255 )
+				throw "Utf8::decode invalid character ("+c+")";
+			untyped __dollar__sset(ret,i,c);
+			i += 1;
+		});
+		return new String( untyped __dollar__ssub(ret,0,i) );
+	}
+
+	public static function iter( s : String, chars : Int -> Void ) : Void {
+		utf8_iter(untyped s.__s,chars);
+	}
+
+	public static function charCodeAt( s : String, index : Int ) : Int {
+		return utf8_get(untyped s.__s,index);
+	}
+
+	public static function validate( s : String ) : Bool {
+		return utf8_validate(untyped s.__s);
+	}
+
+	public static function length( s : String ) : Int {
+		return utf8_length(untyped s.__s);
+	}
+
+	public static function compare( a : String, b : String ) : Int {
+		return utf8_compare(untyped a.__s,untyped b.__s);
+	}
+
+	public static function sub( s : String, pos : Int, len : Int ) : String {
+		return new String(utf8_sub(untyped s.__s,pos,len));
+	}
+
+	static var utf8_buf_alloc = neko.Lib.load("std","utf8_buf_alloc",1);
+	static var utf8_buf_add = neko.Lib.load("std","utf8_buf_add",2);
+	static var utf8_buf_content = neko.Lib.load("std","utf8_buf_content",1);
+	static var utf8_buf_length = neko.Lib.load("std","utf8_buf_length",1);
+	static var utf8_iter = neko.Lib.load("std","utf8_iter",2);
+
+	static var utf8_get = neko.Lib.load("std","utf8_get",2);
+	static var utf8_validate = neko.Lib.load("std","utf8_validate",1);
+	static var utf8_length = neko.Lib.load("std","utf8_length",1);
+	static var utf8_compare = neko.Lib.load("std","utf8_compare",2);
+	static var utf8_sub = neko.Lib.load("std","utf8_sub",3);
+
+}

std/neko/_std/haxe/Utf8.hx

@@ -22,6 +22,7 @@
 package haxe;
 
 @:coreApi
+@:deprecate('haxe.Utf8 is deprecated. Use UnicodeString instead.')
 class Utf8 {
 
 	var __b : Dynamic;

std/php/_std/haxe/Utf8.hx

@@ -24,6 +24,7 @@ package haxe;
 import php.Global;
 
 @:coreApi
+@:deprecate('haxe.Utf8 is deprecated. Use UnicodeString instead.')
 class Utf8 {
 
 	var __b : String;