/* 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 escape(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;
}

var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64DecodeChars = new Array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);
//???Base64??
function base64encode(str) {
    var out, i, len;
    var c1, c2, c3;
    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
	 c1 = str.charCodeAt(i++) & 0xff;
	 if(i == len)
	 {
	     out += base64EncodeChars.charAt(c1 >> 2);
	     out += base64EncodeChars.charAt((c1 & 0x3) << 4);
	     out += "==";
	     break;
	 }
	 c2 = str.charCodeAt(i++);
	 if(i == len)
	 {
	     out += base64EncodeChars.charAt(c1 >> 2);
	     out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	     out += base64EncodeChars.charAt((c2 & 0xF) << 2);
	     out += "=";
	     break;
	 }
	 c3 = str.charCodeAt(i++);
	 out += base64EncodeChars.charAt(c1 >> 2);
	 out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	 out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6));
	 out += base64EncodeChars.charAt(c3 & 0x3F);
	 }
    return out;
}

//???Base64??
function base64decode(str) {
    var c1, c2, c3, c4;
    var i, len, out;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
	 /* c1 */
	 do {
	     c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
	 } while(i < len && c1 == -1);
	 if(c1 == -1)
	     break;
	
	 /* c2 */
	 do {
	     c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
	 } while(i < len && c2 == -1);
	 if(c2 == -1)
	     break;
	
	 out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));
	
	 /* c3 */
	 do {
	     c3 = str.charCodeAt(i++) & 0xff;
	     if(c3 == 61)
	  return out;
	     c3 = base64DecodeChars[c3];
	 } while(i < len && c3 == -1);
	 if(c3 == -1)
	     break;
	
	 out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
	
	 /* c4 */
	 do {
	     c4 = str.charCodeAt(i++) & 0xff;
	     if(c4 == 61)
	  return out;
	     c4 = base64DecodeChars[c4];
	 } while(i < len && c4 == -1);
	 if(c4 == -1)
	     break;
	 out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
     }
    return out;
}