structjs/lib/types/number.js

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

var utils = require('../utils')

var StructNumber = module.exports = function(read, write, length) {
  this.methods = { read: read, write: write }
  Object.defineProperties(this, {
    _offset: { value: null, writable: true },
    _length: { value: null, writable: true }
  })
  utils.options.call(this, length)
}

StructNumber.prototype.with = function(opts) {
  if (!opts.length) opts.length = this._length
  return new StructNumber(this.methods.read, this.methods.write, opts)
}

StructNumber.prototype.from = function(offset) {
  return this.with({ external: true, offset: offset })
}

StructNumber.prototype.read = function read(buffer, offset) {
  var parent = read.caller.parent
  return buffer[this.methods.read](this.external ? this.offsetFor(parent) : offset)
}

StructNumber.prototype.write = function write(buffer, offset, value) {
  var parent = write.caller.parent
  buffer[this.methods.write](this.external ? this.offsetFor(parent) : offset, value)
}

StructNumber.prototype.lengthFor = function() {
  return 1
}

StructNumber.prototype.sizeFor = function() {
  return this._length
}

utils.methodsFor(StructNumber.prototype, '_offset', 'offsetFor', 'setOffset')