Introduction

nodejs struct like C Language

Installation

To install:

npm install nstruct

Example

var NStruct = require('nstruct');

var ns = new NStruct();

var buffer = Buffer.from([0x00, 0x01, 0x47, 0x6F, 0x64, 0x64, 0x01, 0xff]);

var template = {
  id: 'UInt16',
  name: 'Char[3]',
  rank: 'UInt8',
  pos: {x: 'UInt8',y: 'UInt8'}
};

var structInstance = ns.bufferToStruct(buffer, template);

console.log(structInstance);

var bufferInstance = ns.structToBuffer(structInstance, template);

console.log(bufferInstance);

Output: { id: 1, name: [ 'G', 'o', 'd' ], rank: 100, pos: { x: 1, y: 255 } } <Buffer 00 01 47 6f 64 64 01 ff>

Basic Type

type	bytes
UInt8	1
UInt16	2
UInt32	4
Int8	1
Int16	2
Int32	4
Char	1
Float	4
Double	8

Array Type

Arrays are supported for all base types

eg: UInt8[2] Float[4]

Template

Basic organization of data structures,like

{ 
  id: 'UInt32',
  name: 'Char[3]',
  rank: 'Int8',
  pos: [{ x: 'UInt8', y:'UInt8' },{ x: 'UInt8', y: 'UInt8' }]
}

Function

sizeof(template) calculate bytes of template

offset(template, field) calculate field offset in template

bufferToStruct(buffer, template) convert to struct from buffer

structToBuffer(struct, template) convert to buffer from struct