Node.jsBuffer.readDoubleBE()方法

原文:https://www . geesforgeks . org/node-js-buffer-readdouble be-method/

Node.js 中的 Buffer.readDoubleBE()方法用于以大端格式从给定偏移量的缓冲区中读取 64 位双精度值。

语法:

Buffer.readDoubleBE( offset )


参数:该方法接受单参数偏移量，该偏移量保存开始读取前要跳过的字节数。偏移值介于 0 <=偏移<= buf . length–8之间。其默认值为 0。

返回值:以大端格式返回整数值。

下面的例子说明了 buf.readDoubleBE()方法在 Node.js 中的使用:

例 1:

// Node program to demonstrate the  
// Buffer.readDoubleBE() method 
// Creating a buffer of given size 
const buf = Buffer.from([10, 20, 30, 40, 50, 60, 70, 80]);
// Display the result 
console.log("Functions of Buffer.readDoubleBe(int)");
console.log(buf.readDoubleBE(0))
console.log(buf); 


输出:

Functions of Buffer.readDoubleBe(int)
4.0888790063059496e-260



例 2:

// Node program to demonstrate the  
// Buffer.readDoubleBE() method 
// Creating a buffer of given size 
const buf = Buffer.from([100, 200, 300, 400, 500, 600, 700, 800]);
// Display the result 
console.log("Functions of Buffer.readDoubleBe(int)"); 
console.log(buf.readDoubleBE(5))
console.log(buf); 


输出:

Functions of Buffer.readDoubleBe(int)
internal/buffer.js:72
throw new ERR_OUT_OF_RANGE(type || 'offset',
^
RangeError [ERR_OUT_OF_RANGE]: The value of "offset" is out of range.
It must be >= 0 and <= 5 0\. received . .

**注意:**以上程序使用`node index.js`命令编译运行。**参考:**T2【https://nodejs . org/docs/latest-v 11 . x/API/buffer . html # buffer _ buf _ readdouble be _ offset=>