shiziyu18_small/we7/resource/js/base64.js

function base64_encode(str) {
	var c1, c2, c3;
	var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	var i = 0, len = str.length, string = '';

	while (i < len) {
		c1 = str.charCodeAt(i++) & 0xff;
		if (i == len) {
			string += base64EncodeChars.charAt(c1 >> 2);
			string += base64EncodeChars.charAt((c1 & 0x3) << 4);
			string += "==";
			break;
		}
		c2 = str.charCodeAt(i++);
		if (i == len) {
			string += base64EncodeChars.charAt(c1 >> 2);
			string += base64EncodeChars.charAt(((c1 & 0x3) << 4)
				| ((c2 & 0xF0) >> 4));
			string += base64EncodeChars.charAt((c2 & 0xF) << 2);
			string += "=";
			break;
		}
		c3 = str.charCodeAt(i++);
		string += base64EncodeChars.charAt(c1 >> 2);
		string += base64EncodeChars.charAt(((c1 & 0x3) << 4)
			| ((c2 & 0xF0) >> 4));
		string += base64EncodeChars.charAt(((c2 & 0xF) << 2)
			| ((c3 & 0xC0) >> 6));
		string += base64EncodeChars.charAt(c3 & 0x3F)
	}
	return string
}

function base64_decode(str) {
	var c1, c2, c3, c4;
	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);
	var i = 0, len = str.length, string = '';

	while (i < len) {
		do {
			c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]
		} while (i < len && c1 == -1);

		if (c1 == -1)
			break;

		do {
			c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]
		} while (i < len && c2 == -1);

		if (c2 == -1)
			break;

		string += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

		do {
			c3 = str.charCodeAt(i++) & 0xff;
			if (c3 == 61)
				return string;

			c3 = base64DecodeChars[c3]
		} while (i < len && c3 == -1);

		if (c3 == -1)
			break;

		string += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));

		do {
			c4 = str.charCodeAt(i++) & 0xff;
			if (c4 == 61)
				return string;
			c4 = base64DecodeChars[c4]
		} while (i < len && c4 == -1);

		if (c4 == -1)
			break;

		string += String.fromCharCode(((c3 & 0x03) << 6) | c4)
	}
	return string;
}
module.exports = {
	'base64_encode': base64_encode,
	'base64_decode': base64_decode
};