blake-hash/lib/api/blake.js

SHA-3 proposal Blake

const Transform = require('readable-stream').Transform

module.exports = class Blake extends Transform {
  constructor (engine, options) {
    super(options)

    this._engine = engine
    this._finalized = false
  }

  _transform (chunk, encoding, callback) {
    let error = null
    try {
      this.update(chunk, encoding)
    } catch (err) {
      error = err
    }

    callback(error)
  }

  _flush (callback) {
    let error = null
    try {
      this.push(this.digest())
    } catch (err) {
      error = err
    }

    callback(error)
  }

  update (data, encoding) {
    if (!Buffer.isBuffer(data) && typeof data !== 'string') throw new TypeError('Data must be a string or a buffer')
    if (this._finalized) throw new Error('Digest already called')
    if (!Buffer.isBuffer(data)) data = Buffer.from(data, encoding)

    this._engine.update(data)

    return this
  }

  digest (encoding) {
    if (this._finalized) throw new Error('Digest already called')
    this._finalized = true

    let digest = this._engine.digest()
    if (encoding !== undefined) digest = digest.toString(encoding)

    return digest
  }
}