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src/main/webapp/static/share/js/base64.js

+/**
+ *create by 2014年7月9日 http://javascript.css-js.com/
+ *BASE64 Encode and Decode By UTF-8 unicode
+ *可以和java的BASE64编码和解码互相转化
+ */
+ 
+    var BASE64_MAPPING = [
+        'A','B','C','D','E','F','G','H',
+        'I','J','K','L','M','N','O','P',
+        'Q','R','S','T','U','V','W','X',
+        'Y','Z','a','b','c','d','e','f',
+        'g','h','i','j','k','l','m','n',
+        'o','p','q','r','s','t','u','v',
+        'w','x','y','z','0','1','2','3',
+        '4','5','6','7','8','9','+','/'
+    ];
+ 
+    /**
+     *ascii convert to binary
+     */
+    var _toBinary = function(ascii){
+        var binary = new Array();
+        while(ascii > 0){
+            var b = ascii%2;
+            ascii = Math.floor(ascii/2);
+            binary.push(b);
+        }
+        /*
+        var len = binary.length;
+        if(6-len > 0){
+            for(var i = 6-len ; i > 0 ; --i){
+                binary.push(0);
+            }
+        }*/
+        binary.reverse();
+        return binary;
+    };
+ 
+    /**
+     *binary convert to decimal
+     */
+    var _toDecimal  = function(binary){
+        var dec = 0;
+        var p = 0;
+        for(var i = binary.length-1 ; i >= 0 ; --i){
+            var b = binary[i];
+            if(b == 1){
+                dec += Math.pow(2 , p);
+            }
+            ++p;
+        }
+        return dec;
+    };
+ 
+    /**
+     *unicode convert to utf-8
+     */
+    var _toUTF8Binary = function(c , binaryArray){
+        var mustLen = (8-(c+1)) + ((c-1)*6);
+        var fatLen = binaryArray.length;
+        var diff = mustLen - fatLen;
+        while(--diff >= 0){
+            binaryArray.unshift(0);
+        }
+        var binary = [];
+        var _c = c;
+        while(--_c >= 0){
+            binary.push(1);
+        }
+        binary.push(0);
+        var i = 0 , len = 8 - (c+1);
+        for(; i < len ; ++i){
+            binary.push(binaryArray[i]);
+        }
+ 
+        for(var j = 0 ; j < c-1 ; ++j){
+            binary.push(1);
+            binary.push(0);
+            var sum = 6;
+            while(--sum >= 0){
+                binary.push(binaryArray[i++]);
+            }
+        }
+        return binary;
+    };
+ 
+    var BASE64 = {
+            /**
+             *BASE64 Encode
+             */
+            encoder:function(str){
+                var base64_Index = [];
+                var binaryArray = [];
+                for(var i = 0 , len = str.length ; i < len ; ++i){
+                    var unicode = str.charCodeAt(i);
+                    var _tmpBinary = _toBinary(unicode);
+                    if(unicode < 0x80){
+                        var _tmpdiff = 8 - _tmpBinary.length;
+                        while(--_tmpdiff >= 0){
+                            _tmpBinary.unshift(0);
+                        }
+                        binaryArray = binaryArray.concat(_tmpBinary);
+                    }else if(unicode >= 0x80 && unicode <= 0x7FF){
+                        binaryArray = binaryArray.concat(_toUTF8Binary(2 , _tmpBinary));
+                    }else if(unicode >= 0x800 && unicode <= 0xFFFF){//UTF-8 3byte
+                        binaryArray = binaryArray.concat(_toUTF8Binary(3 , _tmpBinary));
+                    }else if(unicode >= 0x10000 && unicode <= 0x1FFFFF){//UTF-8 4byte
+                        binaryArray = binaryArray.concat(_toUTF8Binary(4 , _tmpBinary));    
+                    }else if(unicode >= 0x200000 && unicode <= 0x3FFFFFF){//UTF-8 5byte
+                        binaryArray = binaryArray.concat(_toUTF8Binary(5 , _tmpBinary));
+                    }else if(unicode >= 4000000 && unicode <= 0x7FFFFFFF){//UTF-8 6byte
+                        binaryArray = binaryArray.concat(_toUTF8Binary(6 , _tmpBinary));
+                    }
+                }
+ 
+                var extra_Zero_Count = 0;
+                for(var i = 0 , len = binaryArray.length ; i < len ; i+=6){
+                    var diff = (i+6)-len;
+                    if(diff == 2){
+                        extra_Zero_Count = 2;
+                    }else if(diff == 4){
+                        extra_Zero_Count = 4;
+                    }
+                    //if(extra_Zero_Count > 0){
+                    //  len += extra_Zero_Count+1;
+                    //}
+                    var _tmpExtra_Zero_Count = extra_Zero_Count;
+                    while(--_tmpExtra_Zero_Count >= 0){
+                        binaryArray.push(0);
+                    }
+                    base64_Index.push(_toDecimal(binaryArray.slice(i , i+6)));
+                }
+ 
+                var base64 = '';
+                for(var i = 0 , len = base64_Index.length ; i < len ; ++i){
+                    base64 += BASE64_MAPPING[base64_Index[i]];
+                }
+ 
+                for(var i = 0 , len = extra_Zero_Count/2 ; i < len ; ++i){
+                    base64 += '=';
+                }
+                return base64;
+            },
+            /**
+             *BASE64  Decode for UTF-8 
+             */
+            decoder : function(_base64Str){
+                var _len = _base64Str.length;
+                var extra_Zero_Count = 0;
+                /**
+                 *计算在进行BASE64编码的时候，补了几个0
+                 */
+                if(_base64Str.charAt(_len-1) == '='){
+                    //alert(_base64Str.charAt(_len-1));
+                    //alert(_base64Str.charAt(_len-2));
+                    if(_base64Str.charAt(_len-2) == '='){//两个等号说明补了4个0
+                        extra_Zero_Count = 4;
+                        _base64Str = _base64Str.substring(0 , _len-2);
+                    }else{//一个等号说明补了2个0
+                        extra_Zero_Count = 2;
+                        _base64Str = _base64Str.substring(0 , _len - 1);
+                    }
+                }
+ 
+                var binaryArray = [];
+                for(var i = 0 , len = _base64Str.length; i < len ; ++i){
+                    var c = _base64Str.charAt(i);
+                    for(var j = 0 , size = BASE64_MAPPING.length ; j < size ; ++j){
+                        if(c == BASE64_MAPPING[j]){
+                            var _tmp = _toBinary(j);
+                            /*不足6位的补0*/
+                            var _tmpLen = _tmp.length;
+                            if(6-_tmpLen > 0){
+                                for(var k = 6-_tmpLen ; k > 0 ; --k){
+                                    _tmp.unshift(0);
+                                }
+                            }
+                            binaryArray = binaryArray.concat(_tmp);
+                            break;
+                        }
+                    }
+                }
+ 
+                if(extra_Zero_Count > 0){
+                    binaryArray = binaryArray.slice(0 , binaryArray.length - extra_Zero_Count);
+                }
+ 
+                var unicode = [];
+                var unicodeBinary = [];
+                for(var i = 0 , len = binaryArray.length ; i < len ; ){
+                    if(binaryArray[i] == 0){
+                        unicode=unicode.concat(_toDecimal(binaryArray.slice(i,i+8)));
+                        i += 8;
+                    }else{
+                        var sum = 0;
+                        while(i < len){
+                            if(binaryArray[i] == 1){
+                                ++sum;
+                            }else{
+                                break;
+                            }
+                            ++i;
+                        }
+                        unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+1 , i+8-sum));
+                        i += 8 - sum;
+                        while(sum > 1){
+                            unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+2 , i+8));
+                            i += 8;
+                            --sum;
+                        }
+                        unicode = unicode.concat(_toDecimal(unicodeBinary));
+                        unicodeBinary = [];
+                    }
+                }
+                //---------直接转换为结果
+                var strResult = '';  
+                for(var i = 0 , len =  unicode.length ; i < len ;++i){  
+                      strResult += String.fromCharCode(unicode[i]);  
+                }
+                return strResult;
+            }
+    };
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