JS SHA1 文件 函数

需要的库

CryptoJS/rollups/sha1.js
CryptoJS/components/lib-typedarrays-min.js

hash: (fobj, callback_end, callback_progress)->
  blob = new Blob()
  read = 0
  unit = 1024 * 1024
  sha1 = CryptoJS.algo.SHA1.create()
  reader = new FileReader()
  reader.onload = (e)->
    bytes = CryptoJS.lib.WordArray.create(new Uint8Array(e.target.result))
    sha1.update bytes
    read += unit

    if read < fobj.size
      callback_progress read / fobj.size
      blob = fobj.slice read, read + unit
      reader.readAsArrayBuffer blob

    else
      hash = sha1.finalize()
      callback_progress 1
      callback_end hash.toString(CryptoJS.enc.Hex)
      @processing = false

  reader.readAsArrayBuffer fobj.slice(read, read + unit)