base64原理及其实现

╰+攻爆jí腚メ 2022-05-26 05:28 209阅读 0赞

## base64原理 ##

> \*base是吧3个8位字节转成4个6位字节，然后在6位字节前面补两个零  
> \*6位字节是0~63都是可见字符

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**用Buffer将一个汉字转成16进制**

var buf=new Buffer('珍');//e7 8f 8d

**将16进制的转成10进制**

//把任意字符转成10进制
    console.log(parseInt("e7",16));//231
    console.log(parseInt("8f",16));//143
    console.log(parseInt("8d",16));//141

**将10进制转成2进制**

//10进制转成任意进制
    console.log((231).toString(2));//11100111
    console.log((143).toString(2));//10001111
    console.log((141).toString(2));//10001101

**按照base64的原理**

11100111 10001111 10001101
    变成
    00111001  00111000  00111110  00001101

**把二进制转成10进制**

//把二进制转成10进制
    console.log(parseInt("00111001",2));//57
    console.log(parseInt("00111000",2));//56
    console.log(parseInt("00111110",2));//62
    console.log(parseInt("00001101",2));//13

**base64**

var str="ABCDEFGHIJKLMNOPQRSTUVWSYZ";
     str+=str.toLowerCase();
     str+='0123456789';
     str+='+/';

**输出**

console.log(str[57],str[56],str[62],str[13]);//5 4 + N

![这里写图片描述][70]

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## 封装 ##

[70]: /images/20220526/4ecc1249ba494fa998a737746bb6739f.png