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Node.js | Buffer.readUInt32BE() Method
  • Last Updated : 30 Dec, 2019

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




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