qrcode/lib/core/numeric-data.js

QRCode / 2d Barcode api with both server side and client side support using canvas

var Mode = require('./mode')

function NumericData (data) {
  this.mode = Mode.NUMERIC
  this.data = data.toString()
}

NumericData.getBitsLength = function getBitsLength (length) {
  return 10 * Math.floor(length / 3) + ((length % 3) ? ((length % 3) * 3 + 1) : 0)
}

NumericData.prototype.getLength = function getLength () {
  return this.data.length
}

NumericData.prototype.getBitsLength = function getBitsLength () {
  return NumericData.getBitsLength(this.data.length)
}

NumericData.prototype.write = function write (bitBuffer) {
  var i, group, value

  // The input data string is divided into groups of three digits,
  // and each group is converted to its 10-bit binary equivalent.
  for (i = 0; i + 3 <= this.data.length; i += 3) {
    group = this.data.substr(i, 3)
    value = parseInt(group, 10)

    bitBuffer.put(value, 10)
  }

  // If the number of input digits is not an exact multiple of three,
  // the final one or two digits are converted to 4 or 7 bits respectively.
  var remainingNum = this.data.length - i
  if (remainingNum > 0) {
    group = this.data.substr(i)
    value = parseInt(group, 10)

    bitBuffer.put(value, remainingNum * 3 + 1)
  }
}

module.exports = NumericData