Base 64符号化復号(JavaScriptバージョン)


<html>
<HTML>
<HEAD>
<TITLE>Base64</TITLE>
<script type='text/javascript'>

var BASE64_ENCODE_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var BASE64_DECODE_CHARS = [-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];
function encodeBase64(str) {
	var c1, c2, c3, i = 0, len = str.length, out=[];
	while (i < len) {
		c1 = str.charCodeAt(i++) & 0xff;
		if (i == len) {
			out.push(BASE64_ENCODE_CHARS.charAt(c1 >> 2));
			out.push(BASE64_ENCODE_CHARS.charAt((c1 & 0x3) << 4));
			out.push('==');
			break;
		}
		c2 = str.charCodeAt(i++);
		if (i == len) {
			out.push(BASE64_ENCODE_CHARS.charAt(c1 >> 2));
			out.push(BASE64_ENCODE_CHARS.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)));
			out.push(BASE64_ENCODE_CHARS.charAt((c2 & 0xF) << 2));
			out.push('=');
			break;
		}
		c3 = str.charCodeAt(i++);
		out.push(BASE64_ENCODE_CHARS.charAt(c1 >> 2));
		out.push(BASE64_ENCODE_CHARS.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)));
		out.push(BASE64_ENCODE_CHARS.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6)));
		out.push(BASE64_ENCODE_CHARS.charAt(c3 & 0x3F));
	}
	return out.join('');
}
function decodeBase64(str) {
	var c1, c2, c3, c4, i = 0, len = str.length, out=[];
	while (i < len) {
		/* c1 */
		do {
			c1 = BASE64_DECODE_CHARS[str.charCodeAt(i++) & 0xff];
		} while (i < len && c1 == -1);
		if (c1 == -1)
			break;
		/* c2 */
		do {
			c2 = BASE64_DECODE_CHARS[str.charCodeAt(i++) & 0xff];
		} while (i < len && c2 == -1);
		if (c2 == -1)
			break;
		out.push(String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4)));
		/* c3 */
		do {
			c3 = str.charCodeAt(i++) & 0xff;
			if (c3 == 61)
				return out.join('');
			c3 = BASE64_DECODE_CHARS[c3];
		} while (i < len && c3 == -1);
		if (c3 == -1)
			break;
		out.push(String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2)));
		/* c4 */
		do {
			c4 = str.charCodeAt(i++) & 0xff;
			if (c4 == 61)
				return out.join('');
			c4 = BASE64_DECODE_CHARS[c4];
		} while (i < len && c4 == -1);
		if (c4 == -1)
			break;
		out.push(String.fromCharCode(((c3 & 0x03) << 6) | c4));
	}
	return out.join('');
}
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;
}

function doIt() {
	var sourceValue = document.getElementById('source').value;
	document.getElementById('output').value = encodeBase64(utf16to8(sourceValue));
	document.getElementById('decode').value = utf8to16(decodeBase64(sourceValue));
}

</script>
<body>
Source :<br>
<textarea id="source" style='width:500;height:80;'></textarea><br><br>
base64 Encode :<br>
<textarea id="output" style='width:500;height:80;'></textarea><br><br>
base64 Eecode :<br>
<textarea id="decode" style='width:500;height:80;'></textarea><br><br>
<input type=button value="Transcoding" onclick="doIt()">
</body>
</html>