Node.js Buffer.readUInt32BE() Method

The Buffer.readUInt32BE() method is an inbuilt application programming interface of class Buffer within the Buffer module which is used to read 32-bit value from an allocated buffer at a specified offset.

Syntax:

Buffer.readUInt32BE( offset )

Parameters: This method accept single parameter offset which specifies the number of bytes to skip before read or simply signify the index in the buffer. The value of offset lies 0 <= offset <= Buffer.length – 4. Its default value is 0.

Return Value: This method returns an integer value that read from buffer in Big Endian format.

Below examples illustrate the use of Buffer.readUInt32BE() method in Node.js:

Example 1:

// Node program to demonstrate the   
// Buffer.readUInt32LE() Method 

   
// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98, 

                    0x16, 0x09, 0x19, 0x96]); 

  
// Printing allocated buffer 
console.log(buf); 

   
// Reading 32 bits data from the buffer 
// and printing it as a string 
console.log(buf.readUInt32BE(0).toString(16)); 
console.log(buf.readUInt32BE(1).toString(16)); 
console.log(buf.readUInt32BE(2).toString(16)); 
console.log(buf.readUInt32BE(3).toString(16)); 
console.log(buf.readUInt32BE(4).toString(16)); 

Output:

<Buffer 21 09 19 98 16 09 19 96>
21091998
9199816
19981609
98160919
16091996

Example 2:

// Node program to demonstrate the   
// Buffer.readUInt32LE() Method 

   
// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98, 

                    0x34, 0xae, 0xe8, 0xff]); 

  
// Printing allocated buffer 
console.log(buf); 

   
// Reading 16bits data from the 
// buffer and printing it as a string 
console.log(buf.readUInt32BE(0).toString(16)); 
console.log(buf.readUInt32LE(0).toString(16)); 
console.log(buf.readUInt32BE(1).toString(16)); 
console.log(buf.readUInt32LE(1).toString(16)); 
console.log(buf.readUInt32BE(2).toString(16)); 
console.log(buf.readUInt32LE(2).toString(16)); 
console.log(buf.readUInt32BE(3).toString(16)); 
console.log(buf.readUInt32LE(3).toString(16)); 
console.log(buf.readUInt32BE(4).toString(16)); 
console.log(buf.readUInt32LE(4).toString(16)); 

Output:

<Buffer 21 09 19 98 34 ae e8 ff>
21091998
98190921
9199834
34981909
199834ae
ae349819
9834aee8
e8ae3498
34aee8ff
ffe8ae34

Example 3:

// Node program to demonstrate the   
// Buffer.readUInt32LE() Method 

// Allocating buffer from array 
const buf = Buffer.from([0x21, 0x09, 0x19, 0x98]); 

// Printing allocated buffer 
console.log(buf); 

// Reading 16bits data from the buffer 
// and printing it as a string 
console.log(buf.readUInt32BE(0).toString(16)); 

// Wrong index is provoded to produce error 
console.log(buf.readUInt32BE(1).toString(16));

Output:

<Buffer 21 09 19 98>
21091998
internal/buffer.js:49
  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 <= 0. Received 1
    at boundsError (internal/buffer.js:49:9)
    at Buffer.readUInt32BE (internal/buffer.js:192:5)
    . . .

Note: The above program will compile and run by using the node index.js command.

Reference: https://nodejs.org/api/buffer.html#buffer_buf_readuint32be_offset

Article Tags :

Node.js

Web Technologies

Node.js-Buffer-module