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219 lines
6.1 KiB
219 lines
6.1 KiB
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(function () { |
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var BASE64_MAPPING = [ |
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', |
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'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', |
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'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', |
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'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', |
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'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', |
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v', |
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'w', 'x', 'y', 'z', '0', '1', '2', '3', |
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'4', '5', '6', '7', '8', '9', '+', '/' |
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]; |
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/** |
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*ascii convert to binary |
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*/ |
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var _toBinary = function (ascii) { |
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var binary = new Array(); |
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while (ascii > 0) { |
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var b = ascii % 2; |
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ascii = Math.floor(ascii / 2); |
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binary.push(b); |
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} |
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/* |
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var len = binary.length; |
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if(6-len > 0){ |
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for(var i = 6-len ; i > 0 ; --i){ |
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binary.push(0); |
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} |
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}*/ |
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binary.reverse(); |
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return binary; |
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}; |
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/** |
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*binary convert to decimal |
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*/ |
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var _toDecimal = function (binary) { |
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var dec = 0; |
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var p = 0; |
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for (var i = binary.length - 1; i >= 0; --i) { |
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var b = binary[i]; |
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if (b == 1) { |
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dec += Math.pow(2, p); |
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} |
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++p; |
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} |
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return dec; |
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}; |
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/** |
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*unicode convert to utf-8 |
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*/ |
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var _toUTF8Binary = function (c, binaryArray) { |
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var mustLen = (8 - (c + 1)) + ((c - 1) * 6); |
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var fatLen = binaryArray.length; |
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var diff = mustLen - fatLen; |
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while (--diff >= 0) { |
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binaryArray.unshift(0); |
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} |
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var binary = []; |
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var _c = c; |
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while (--_c >= 0) { |
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binary.push(1); |
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} |
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binary.push(0); |
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var i = 0, len = 8 - (c + 1); |
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for (; i < len; ++i) { |
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binary.push(binaryArray[i]); |
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} |
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for (var j = 0; j < c - 1; ++j) { |
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binary.push(1); |
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binary.push(0); |
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var sum = 6; |
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while (--sum >= 0) { |
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binary.push(binaryArray[i++]); |
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} |
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} |
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return binary; |
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}; |
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var __BASE64 = { |
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/** |
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*BASE64 Encode |
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*/ |
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encoder: function (str) { |
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var base64_Index = []; |
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var binaryArray = []; |
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for (var i = 0, len = str.length; i < len; ++i) { |
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var unicode = str.charCodeAt(i); |
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var _tmpBinary = _toBinary(unicode); |
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if (unicode < 0x80) { |
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var _tmpdiff = 8 - _tmpBinary.length; |
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while (--_tmpdiff >= 0) { |
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_tmpBinary.unshift(0); |
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} |
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binaryArray = binaryArray.concat(_tmpBinary); |
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} else if (unicode >= 0x80 && unicode <= 0x7FF) { |
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binaryArray = binaryArray.concat(_toUTF8Binary(2, _tmpBinary)); |
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} else if (unicode >= 0x800 && unicode <= 0xFFFF) {//UTF-8 3byte |
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binaryArray = binaryArray.concat(_toUTF8Binary(3, _tmpBinary)); |
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} else if (unicode >= 0x10000 && unicode <= 0x1FFFFF) {//UTF-8 4byte |
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binaryArray = binaryArray.concat(_toUTF8Binary(4, _tmpBinary)); |
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} else if (unicode >= 0x200000 && unicode <= 0x3FFFFFF) {//UTF-8 5byte |
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binaryArray = binaryArray.concat(_toUTF8Binary(5, _tmpBinary)); |
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} else if (unicode >= 4000000 && unicode <= 0x7FFFFFFF) {//UTF-8 6byte |
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binaryArray = binaryArray.concat(_toUTF8Binary(6, _tmpBinary)); |
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} |
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} |
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var extra_Zero_Count = 0; |
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for (var i = 0, len = binaryArray.length; i < len; i += 6) { |
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var diff = (i + 6) - len; |
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if (diff == 2) { |
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extra_Zero_Count = 2; |
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} else if (diff == 4) { |
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extra_Zero_Count = 4; |
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} |
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//if(extra_Zero_Count > 0){ |
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// len += extra_Zero_Count+1; |
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//} |
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var _tmpExtra_Zero_Count = extra_Zero_Count; |
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while (--_tmpExtra_Zero_Count >= 0) { |
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binaryArray.push(0); |
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} |
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base64_Index.push(_toDecimal(binaryArray.slice(i, i + 6))); |
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} |
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var base64 = ''; |
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for (var i = 0, len = base64_Index.length; i < len; ++i) { |
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base64 += BASE64_MAPPING[base64_Index[i]]; |
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} |
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for (var i = 0, len = extra_Zero_Count / 2; i < len; ++i) { |
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base64 += '='; |
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} |
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return base64; |
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}, |
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/** |
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*BASE64 Decode for UTF-8 |
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*/ |
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decoder: function (_base64Str) { |
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var _len = _base64Str.length; |
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var extra_Zero_Count = 0; |
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/** |
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*计算在进行BASE64编码的时候,补了几个0 |
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*/ |
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if (_base64Str.charAt(_len - 1) == '=') { |
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//alert(_base64Str.charAt(_len-1)); |
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//alert(_base64Str.charAt(_len-2)); |
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if (_base64Str.charAt(_len - 2) == '=') {//两个等号说明补了4个0 |
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extra_Zero_Count = 4; |
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_base64Str = _base64Str.substring(0, _len - 2); |
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} else {//一个等号说明补了2个0 |
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extra_Zero_Count = 2; |
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_base64Str = _base64Str.substring(0, _len - 1); |
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} |
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} |
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var binaryArray = []; |
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for (var i = 0, len = _base64Str.length; i < len; ++i) { |
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var c = _base64Str.charAt(i); |
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for (var j = 0, size = BASE64_MAPPING.length; j < size; ++j) { |
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if (c == BASE64_MAPPING[j]) { |
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var _tmp = _toBinary(j); |
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/*不足6位的补0*/ |
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var _tmpLen = _tmp.length; |
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if (6 - _tmpLen > 0) { |
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for (var k = 6 - _tmpLen; k > 0; --k) { |
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_tmp.unshift(0); |
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} |
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} |
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binaryArray = binaryArray.concat(_tmp); |
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break; |
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} |
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} |
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} |
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if (extra_Zero_Count > 0) { |
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binaryArray = binaryArray.slice(0, binaryArray.length - extra_Zero_Count); |
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} |
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var unicode = []; |
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var unicodeBinary = []; |
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for (var i = 0, len = binaryArray.length; i < len;) { |
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if (binaryArray[i] == 0) { |
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unicode = unicode.concat(_toDecimal(binaryArray.slice(i, i + 8))); |
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i += 8; |
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} else { |
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var sum = 0; |
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while (i < len) { |
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if (binaryArray[i] == 1) { |
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++sum; |
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} else { |
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break; |
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} |
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++i; |
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} |
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unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 1, i + 8 - sum)); |
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i += 8 - sum; |
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while (sum > 1) { |
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unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 2, i + 8)); |
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i += 8; |
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--sum; |
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} |
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unicode = unicode.concat(_toDecimal(unicodeBinary)); |
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unicodeBinary = []; |
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} |
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} |
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return unicode; |
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} |
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}; |
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//window.BASE64 = __BASE64; |
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module.exports = { |
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CusBASE64: __BASE64 |
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} |
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})(); |