c-struct

A fast binary data packing & unpacking library for node.js designed for multiplayer games.

What can it do?

• 8, 16, 24, 32, 40, 48, (56 and 64*) bit unsigned integers.
• String with length and null-terminated cstrings.
• Boolean, nibble, float and double.
• Big and little endianness.
• Schema based packing and unpacking.
• Unpack from buffer to object.
• Pack from object to buffer.
• Pack with default value if key isn't specified.

More

• Available via npm.
• Zero production dependencies.

Installation

npm install c-struct --save

Execute $ node examples/ to see the examples.

Usage

Unpacking

var _ = require('c-struct');

var playerSchema = new _.Schema({
  id: _.type.uint16,
  name: _.type.string(16),
  hp: _.type.uint24,
  exp: _.type.uint32,
  status: _.type.uint8,
  motd: _.type.string(), // null-terminated if no length
  motw: _.type.string(), // cstring if no length
  skills: [{
    id: _.type.uint8,
    name: _.type.string(32),
    secret: _.type.uint40
  }],
  position: {
    x: _.type.uint16,
    y: _.type.uint16
  },
  hash: _.type.uint48
});

// register to cache
_.register('Player', playerSchema);

// object to buffer | this can be on another file
var buf = _.packSync('Player', {
  id: 1,
  name: 'Foobar',
  hp: 1000,
  exp: 88888888,
  status: 100,
  skills: [{
    id: 1,
    name: 'traps of thunder',
    secret: 5151515151
  }, {
    id: 2,
  }, {
    name: 'fatal blow'
  }, {
    id: 3,
    name: 'galvano strike'
  }],
  position: {
    x: 102,
    y: 351
  },
  motd: 'welcome',
  motw: 'weekly',
  hash: 99999999,
});

Packing

var _ = require('c-struct');

var playerSchema = new _.Schema({
  id: _.type.uint16,
  name: _.type.string(16),
  hp: _.type.uint24,
  exp: _.type.uint32,
  status: _.type.uint8,
  motd: _.type.string(), // null-terminated if no length
  motw: _.type.string(), // cstring if no length
  skills: [{
    id: _.type.uint8,
    name: _.type.string(32),
    secret: _.type.uint40
  }],
  position: {
    x: _.type.uint16,
    y: _.type.uint16
  },
  hash: _.type.uint48
});

// register to cache
_.register('Player', playerSchema);

// buffer to object | this can be on another file
var obj = _.unpackSync('Player', BUFFER_HERE);

API

Currently only unsigned values in little endian are supported

_.type.uint8    // unsigned char
_.type.uint16   // unsigned short
_.type.uint24
_.type.uint32   // unsigned long
_.type.uint40
_.type.uint48
_.type.uint56
_.type.uint64

You can also specify default values

_.type.u8(9999) // default value 9999
_.type.u16(999) // default value 999
_.type.u24(888) // default value 888
_.type.u32(777) // default value 777
_.type.u40(666) // default value 666
_.type.u48(555) // default value 555
_.type.u56(444) // default value 444
_.type.u64(333) // default value 333

Configurations

There is currently no configs.

TODO

• add configurable endianness
• add async methods
• add signed
• add boolean and nibble
• add float and double
• add benchmark
• documentation
• more testing