/* utf.js - UTF-8 <=> UTF-16 convertion
 *
 * Copyright (C) 1999 Masanao Izumo <iz@onicos.co.jp>
 * Version: 1.0
 * LastModified: Dec 25 1999
 * This library is free. You can redistribute it and/or modify it.
 */

/*
 * Interfaces:
 * utf8 = utf16to8(utf16);
 * utf16 = utf16to8(utf8);
 */

function utf16to8(str) {
 var out, i, len, c;

 out = "";
 len = str.length;
 for(i = 0; i < len; i++) {
	c = str.charCodeAt(i);
	if ((c >= 0x0001) && (c <= 0x007F)) {
	 out += str.charAt(i);
	} else if (c > 0x07FF) {
	 out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
	 out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
	 out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
	} else {
	 out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
	 out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
	}
 }
 return out;
}

function utf8to16(str) {
 var out, i, len, c;
 var char2, char3;

 out = "";
 len = str.length;
 i = 0;
 while(i < len) {
	c = str.charCodeAt(i++);
	switch(c >> 4)
	{ 
	 case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
	 // 0xxxxxxx
	 out += str.charAt(i-1);
	 break;
	 case 12: case 13:
	 // 110x xxxx  10xx xxxx
	 char2 = str.charCodeAt(i++);
	 out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
	 break;
	 case 14:
	 // 1110 xxxx 10xx xxxx 10xx xxxx
	 char2 = str.charCodeAt(i++);
	 char3 = str.charCodeAt(i++);
	 out += String.fromCharCode(((c & 0x0F) << 12) |
					  ((char2 & 0x3F) << 6) |
					  ((char3 & 0x3F) << 0));
	 break;
	}
 }

 return out;
}