import { memcpy } from './mem'
import { Type } from './Type'

export function ConstString(size) {
  const obj = { _size: size }
  Object.setPrototypeOf(obj, ConstString.prototype)
  obj.new(ConstString, arguments)
  return obj
}
ConstString.prototype.serialize = function (dv, src) {
  const encoder = new TextEncoder('utf-8')
  const encoded = new DataView(encoder.encode(src).buffer, 0, this._size)

  if (dv.byteLength < encoded.byteLength) {
    throw new Error(this._name + ' too small buffer')
  }
  if (src.length != this._size) {
    throw new Error(this._name + ' should be ' + this._size + ' symbols length')
  }

  memcpy(dv, encoded)
  return
}
ConstString.prototype.parse = function (dv) {
  const frame = new DataView(dv.buffer, dv.byteOffset, this._size)
  const decoder = new TextDecoder('utf-8')
  return decoder.decode(frame)
}
ConstString.prototype.isHeadless = function () {
  return false
}
ConstString.prototype.sizeof = function () {
  return this._size
}
Object.setPrototypeOf(ConstString.prototype, Type.prototype)
Object.freeze(ConstString.prototype)