JavaScript加密脚本中使用的不熟悉的字符 [英] Unfamiliar characters used in JavaScript encryption script

问题描述

  function permutationGenerator（nNumElements）{
 this.nNumElements = nNumElements; 
 this.antranspositions = new Array; 
 var k = 0; （i = 0; i< nNumElements  -  1; i ++）
（j = i + 1; j< nNumElements; j ++）
 this.antranspositions [k ++] = i<< 8）|焦耳; 
 //保持两个位置作为lo和hi字节！ 
 this.nNumtranspositions = k; 
 this.fromCycle = permutationGenerator_fromCycle; 
} 
  

任何人都可以解释使用双重小于符号<以及单管道| ？

在脚本的后面，双倍大于符号也出现>>，也是单个&符号。

  function permutationGenerator_fromCycle（anCycle）{
 var anpermutation = new Array（this.nNumElements）; （var i = 0; i< this.nNumElements; i ++）ancolorutation [i] = i; 
 （var i = 0; i< anCycle.length; i ++）{
 var nT = this.antranspositions [anCycle [i]]; 
 
 var n1 = nT& 255; 
 var n2 =（nT>> 8）& 255; // JC 
 nT = anatomutation [n1]; 
 anatomutation [n1] = anpermutation [n2]; 
 anatomutation [n2] = nT; 
} 
返回anpermutation; 
} 
  

我熟悉单一<或>当然逻辑和和逻辑||

想法？

解决方案

左移8位和按位OR与j。

< 是左移操作符。将变量中的位移动留下指示的位置数。

>> 是右移操作符。将变量中的位向右移动指示的位置数。

| 是按位OR运算符。在两个操作数的每一位上执行逻辑或。

& 是按位AND运算符。对两个操作数中的每一位执行逻辑和。

Here is an excerpt from a JS encryption script that I am studying.

function permutationGenerator(nNumElements) {
    this.nNumElements     = nNumElements;
    this.antranspositions = new Array;
    var k = 0;
    for (i = 0; i < nNumElements - 1; i++)
    for (j = i + 1; j < nNumElements; j++)
    this.antranspositions[ k++ ] = ( i << 8 ) | j;
    // keep two positions as lo and hi byte!
    this.nNumtranspositions = k;
    this.fromCycle = permutationGenerator_fromCycle;
}

Can anyone explain the use of the double less than signs <<, as well as the single pipe | ?

Later in the script double greater than signs occur as well >>, also single ampersand & .

function permutationGenerator_fromCycle(anCycle) {
    var anpermutation = new Array(this.nNumElements);
    for (var i = 0; i < this.nNumElements; i++) anpermutation[i] = i;
    for (var i = 0; i < anCycle.length; i++) {
        var nT = this.antranspositions[anCycle[i]];
        var n1 = nT & 255;
        var n2 = (nT >> 8) & 255; // JC
        nT = anpermutation[n1];
        anpermutation[n1] = anpermutation[n2];
        anpermutation[n2] = nT;
    }
    return anpermutation;
}

I am familiar with single < or > and of course logical && and logical || .

Thoughts?

解决方案

Left shift 8 bits and bitwise OR with j.

<< is the left shift operator. Shifts the bits in the variable left the number of positions indicated.

>> is the right shift operator. Shifts the bits in the variable right the number of position indicated.

| is the bitwise OR operator. Performs a logical OR on each bit in the two operands.

& is the bitwise AND operator. Performs a logical AND on each bit in the two operands.

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