Instructions for the buffer.copy method in node.js

method description:

Perform copy and replace operations between different buffer.

Copies the data from the source buffer and replaces it to the specified location of the target buffer.

syntax:

buffer.copy(targetBuffer, [targetStart], [sourceStart], [sourceEnd])

receive parameters:

targetBuffer               target buffer

targetStart                   buffer data replacement starting position

sourceStart                 source buffer data copy starting location

sourceEnd                 source buffer data copy end location

example:

In this example, data between buf1, 16 and 20 are extracted, copied into buf2, and replaced from buf2 position 8.

buf1 = new Buffer(26);

buf2 = new Buffer(26);

for (var i = 0 ; i < 26 ; i++) {

  buf1[i] = i + 97; // 97 is ASCII a

  buf2[i] = 33; // ASCII !

}

buf1.copy(buf2, 8, 16, 20);

console.log(buf2.toString('ascii', 0, 25));