Adler32(asm.js)

adler32.asm.js

function adler32_asm(array) {
  function asm(stdlib, foreign, heap) {
    "use asm";

    var array = new stdlib.Uint8Array(heap);

    function adler32(length) {
      length = length | 0;

      return update(1, length) | 0;
    }

    function update(adler, length) {
      adler = adler | 0;
      length = length | 0;

      var s1 = 0;
      var s2 = 0;
      var len = 0;
      var tlen = 0;
      var index = 0;

      s1 = adler & 0xffff;
      s2 = (adler >>> 16) & 0xffff;

      while (length | 0 > 0) {
        tlen = (length | 0) > 5550 ? 5550 : length;
        length = length - tlen | 0;

        do {
          s1 = s1 + (array[index] | 0) | 0;
          index = index + 1 | 0;
          s2 = s1 + s2 | 0;
        } while (tlen = tlen - 1 | 0);

        s1 = (s1 | 0) % 65521 | 0;
        s2 = (s2 | 0) % 65521 | 0;
      }

      return ((s2 << 16) | s1) | 0;
    }

    return {adler32: adler32, update: update};
  }

  return asm(window, {}, array.buffer).adler32(array.length) >>> 0;
}