Implement md5 hash in crypto library.

lib/crypto/md5.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// The MD5 hasher is used to compute an MD5 message digest.
+class _MD5 extends _HashBase implements MD5 {
+  _MD5() : super(16, 4, false) {
+    _h[0] = 0x67452301;
+    _h[1] = 0xefcdab89;
+    _h[2] = 0x98badcfe;
+    _h[3] = 0x10325476;
+  }
+
+  // Returns a new instance of this Hash.
+  MD5 newInstance() {
+    return new MD5();
+  }
+
+  static final _k = const [
+    0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a,
+    0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
+    0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340,
+    0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
+    0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8,
+    0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
+    0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa,
+    0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
+    0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92,
+    0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
+    0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 ];
+
+  static final _r = const [
+    7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5,  9, 14,
+    20, 5,  9, 14, 20, 5,  9, 14, 20, 5,  9, 14, 20, 4, 11, 16, 23, 4, 11,
+    16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6,
+    10, 15, 21, 6, 10, 15, 21 ];
+
+  // Compute one iteration of the MD5 algorithm with a chunk of
+  // 16 32-bit pieces.
+  void _updateHash(List<int> m) {
+    assert(m.length == 16);
+
+    var a = _h[0];
+    var b = _h[1];
+    var c = _h[2];
+    var d = _h[3];
+
+    var t0;
+    var t1;
+
+    for (var i = 0; i < 64; i++) {
+      if (i < 16) {
+        t0 = (b & c) | ((~b & _MASK_32) & d);
+        t1 = i;
+      } else if (i < 32) {
+        t0 = (d & b) | ((~d & _MASK_32) & c);
+        t1 = ((5 * i) + 1) % 16;
+      } else if (i < 48) {
+        t0 = b ^ c ^ d;
+        t1 = ((3 * i) + 5) % 16;
+      } else {
+        t0 = c ^ (b | (~d & _MASK_32));
+        t1 = (7 * i) % 16;
+      }
+
+      var temp = d;
+      d = c;
+      c = b;
+      b = _add32(b, _rotl32(_add32(_add32(a, t0),
+                                   _add32(_k[i], m[t1])),
+                            _r[i]));
+      a = temp;
+    }
+
+    _h[0] = _add32(a, _h[0]);
+    _h[1] = _add32(b, _h[1]);
+    _h[2] = _add32(c, _h[2]);
+    _h[3] = _add32(d, _h[3]);
+  }
+}