js实现base32编码

    在网上找了一圈，想找一个js实现base32编码的，网上只有实现base64编码的，其实原理都是一样的。都是将字符的ASCII码分组后再重新组 合，区别只是每组包含的有效的bytes不同，base64是将3个ASCII字节，组合成4个base字节。而base32是将5个ASCII字节组合 成8个base字节。
    下面是我根据java实现base32编码改编的。可以实现对中文的编码。

 

    核心的加密和解密函数如下，附件里是完整的代码，包括对中文的支持函数（对中文的编码是从网上引用的）。

 

/**
*加密函数
*返回被编码加密的字符串
*/

var getEncodeString =  function (srcString){
		//var srcString = 'abc';
		
		var          i        = 0;
		var          index    = 0;
		var          digit    = 0;
		var          currByte;
		var          nextByte;
		var retrunString = '';
		
		for (var i=0; i< srcString.length;) {
			//var          index    = 0;
			currByte = (srcString.charCodeAt(i) >= 0) ? srcString.charCodeAt(i)
									   : (srcString.charCodeAt(i) + 256); 

			if (index > 3) {
				if ((i + 1) < srcString.length) {
				       nextByte = (srcString.charCodeAt(i + 1) >= 0) 
                                                 ? srcString.charCodeAt(i + 1)
                                                  : (srcString.charCodeAt(i + 1) + 256);
				} else {
					nextByte = 0;
				}

				digit     = currByte & (0xFF >> index);
				index     = (index + 5) % 8;
				digit <<= index;
				digit |= (nextByte >> (8 - index));
				i++;
			} else {
				digit     = (currByte >> (8 - (index + 5))) & 0x1F;
				index     = (index + 5) % 8;

				if (index == 0) {
					i++;
				}
			}

			retrunString = retrunString + BASE32CHAR.charAt(digit);
		}
return retrunString.toLowerCase();
}
		
/**
*解密函数
*返回解密的字符串
*/
 var getDecodeString = function (encodeString){
		var    i;
		var    index;
		var    lookup;
		var    offset;
		var    digit;
		var encodeString = encodeString.toUpperCase();
		var stringLen = parseInt((encodeString.length * 5) / 8);
		var bytes = new Array(stringLen);
		for ( var a=0;a<stringLen;a++){
			bytes[a]=0;
		}

		for (i = 0, index = 0, offset = 0; i < encodeString.length; i++) {
			var charCode0 = '0'.charCodeAt(0);
			lookup = encodeString.charCodeAt(i) - charCode0;

			if ((lookup < 0) || (lookup >= BASE32LOOOKUP.length)) {
				continue;
			}

			digit = BASE32LOOOKUP[lookup];

			if (digit == 0xFF) {
				continue;
			}

			if (index <= 3) {
				index = (index + 5) % 8;

				if (index == 0) {
					bytes[offset] = bytes[offset] | digit;
					
					offset++;

					if (offset >= bytes.length) {
						break;
					}
				} else {
					bytes[offset] = bytes[offset] | (digit << (8 - index));
					
				}
			} else {
				index = (index + 5) % 8;
				bytes[offset] = bytes[offset] | (digit >>> index);
				
				offset++;

				if (offset >= bytes.length) {
					break;
				}

				bytes[offset] = bytes[offset] | (digit << (8 - index));
				if(bytes[offset]>=256){
				
					//var lp = parseInt(bytes[offset]/256);
				  
					bytes[offset] %= 256; 
				}
			}
		}

		//return bytes.join(',');
		var realkeyString = '';
		var decodeString = '';
		for ( var a=0;a<bytes.length;a++){
										
			var realkey  = String.fromCharCode(bytes[a]);  
			realkeyString += realkey;
			//decodeString += bytes[a];
			
		}
		return realkeyString;
		
} 
		
		
				
		var returnEncodeStr = getEncodeString(strUnicode2Ansi('你是我的宝贝'));
		
		
		var returnDecodeStr = strAnsi2Unicode(getDecodeString(returnEncodeStr));
			
		alert(returnDecodeStr);

})()