add hw2

node_modules/pako/lib/zlib/adler32.js

@@ -0,0 +1,51 @@
+'use strict';
+
+// Note: adler32 takes 12% for level 0 and 2% for level 6.
+// It isn't worth it to make additional optimizations as in original.
+// Small size is preferable.
+
+// (C) 1995-2013 Jean-loup Gailly and Mark Adler
+// (C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//   claim that you wrote the original software. If you use this software
+//   in a product, an acknowledgment in the product documentation would be
+//   appreciated but is not required.
+// 2. Altered source versions must be plainly marked as such, and must not be
+//   misrepresented as being the original software.
+// 3. This notice may not be removed or altered from any source distribution.
+
+const adler32 = (adler, buf, len, pos) => {
+  let s1 = (adler & 0xffff) |0,
+      s2 = ((adler >>> 16) & 0xffff) |0,
+      n = 0;
+
+  while (len !== 0) {
+    // Set limit ~ twice less than 5552, to keep
+    // s2 in 31-bits, because we force signed ints.
+    // in other case %= will fail.
+    n = len > 2000 ? 2000 : len;
+    len -= n;
+
+    do {
+      s1 = (s1 + buf[pos++]) |0;
+      s2 = (s2 + s1) |0;
+    } while (--n);
+
+    s1 %= 65521;
+    s2 %= 65521;
+  }
+
+  return (s1 | (s2 << 16)) |0;
+};
+
+
+module.exports = adler32;