php中的base64decode 与js中的互相转换

<script language='javascript'>
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;
}

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);

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;
}

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;
}
//input base64 encode
function str_decode(str){
??????? return utf8to16(base64decode(str));
}
function str_encode(str){
??? return base64encode(utf16to8(str));
}
</script>