Node.js Buffer.readDoubleBE()用法及代码示例

Node.js中的Buffer.readDoubleBE()方法用于以Big Endian格式从给定偏移量的缓冲区中读取64位double。

用法:

Buffer.readDoubleBE( offset )

参数：此方法接受单个参数偏移量，该偏移量包含开始读取之前要跳过的字节数。 offset的值介于0之间

返回值：它以big endian格式返回整数值。

以下示例说明了在Node.js中使用buf.readDoubleBE()方法：

范例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
<Buffer 0a 14 1e 28 32 3c 46 50>

范例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 
Note: The above program will compile and run by using the node index.js command.
Reference: https://nodejs.org/docs/latest-v11.x/api/buffer.html#buffer_buf_readdoublebe_offset