1// Note: adler32 takes 12% for level 0 and 2% for level 6.
 2// It doesn't worth to make additional optimizationa as in original.
 3// Small size is preferable.
 4
 5export default function adler32(adler, buf, len, pos) {
 6  var s1 = (adler & 0xffff) |0,
 7      s2 = ((adler >>> 16) & 0xffff) |0,
 8      n = 0;
 9
10  while (len !== 0) {
11    // Set limit ~ twice less than 5552, to keep
12    // s2 in 31-bits, because we force signed ints.
13    // in other case %= will fail.
14    n = len > 2000 ? 2000 : len;
15    len -= n;
16
17    do {
18      s1 = (s1 + buf[pos++]) |0;
19      s2 = (s2 + s1) |0;
20    } while (--n);
21
22    s1 %= 65521;
23    s2 %= 65521;
24  }
25
26  return (s1 | (s2 << 16)) |0;
27}