structjs/lib/utils.js

**Structjs** allows mapping of contiguously allocated binary data to JavaScript objects for both Node.js and the Browser.

var StructReference = require('./types/reference')

exports.methodsFor = function(obj, prop, get, set) {
  obj[get] = function(parent) {
    if (!this[prop]) return 0
    if (this[prop] instanceof StructReference)
      return parent[this[prop].prop]
    else if (typeof this[prop] === 'function')
      return this[prop].call(parent)
    return this[prop]
  }
  if (!set) return
  obj[set] = function(value, parent) {
    if (this[prop] instanceof StructReference)
      parent[this[prop].prop] = value
    else this[prop] = value
  }
}

exports.options = function(opts) {
  if (typeof opts === 'object') {
    this._offset      = opts.offset
    this._length      = opts.length
    this._size        = opts.size
    this.$unpacked    = opts.$unpacked
    this.$packing     = opts.$packing
    this.external     = opts.external === true
    this.storage      = opts.storage
    this.littleEndian = opts.littleEndian === true
  } else {
    this._length  = opts
  }
}