Use hash map for event handler file descriptor map

runtime/bin/utils.h

+// 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.
+
+#ifndef BIN_UTILS_H_
+#define BIN_UTILS_H_
+
+// TODO(sgjesse): Should this be moved to platform/utils.h? How about

[Mads Ager (chromium), 2012/01/13 13:33:16]

I think we should share this with vm/utils.h.

PowerOf2 is already there. There is also a word hashing function. Maybe we
should use that one instead of the ones you have added here?

[Søren Gjesse, 2012/01/13 14:51:23]

Started http://codereview.chromium.org/9209001/ for moving utils.h and utils.cc
from vm/ to platform/ for sharing PowerOfTwo and hash function. When that has
landed I will merge and continue on this one.

[Søren Gjesse, 2012/01/16 14:14:58]

Removed bin/utils.h and used PowerOfTwo and WordHash from platform/utils.h

+// vm/utils.h?
+
+// ----------------------------------------------------------------------------
+// Bit functions.
+
+// Returns true iff x is a power of 2 (or zero). Cannot be used with the
+// maximally negative value of the type T (the -1 overflows).
+template <typename T>
+inline bool IsPowerOf2(T x) {
+  return (x & (x - 1)) == 0;
+}
+
+// ----------------------------------------------------------------------------
+// Hash functions.
+
+// Thomas Wang, Integer Hash Functions.
+// http://www.concentric.net/~Ttwang/tech/inthash.htm
+inline uint32_t ComputeIntegerHash(uint32_t key) {
+  uint32_t hash = key;
+  hash = ~hash + (hash << 15);  // hash = (hash << 15) - hash - 1;
+  hash = hash ^ (hash >> 12);
+  hash = hash + (hash << 2);
+  hash = hash ^ (hash >> 4);
+  hash = hash * 2057;  // hash = (hash + (hash << 3)) + (hash << 11);
+  hash = hash ^ (hash >> 16);
+  return hash;
+}
+
+
+inline uint32_t ComputeLongHash(uint64_t key) {
+  uint64_t hash = key;
+  hash = ~hash + (hash << 18);  // hash = (hash << 18) - hash - 1;
+  hash = hash ^ (hash >> 31);
+  hash = hash * 21;  // hash = (hash + (hash << 2)) + (hash << 4);
+  hash = hash ^ (hash >> 11);
+  hash = hash + (hash << 6);
+  hash = hash ^ (hash >> 22);
+  return (uint32_t) hash;
+}
+
+
+inline uint32_t ComputePointerHash(void* ptr) {
+  return ComputeIntegerHash(
+      static_cast<uint32_t>(reinterpret_cast<intptr_t>(ptr)));
+}
+
+
+#endif  // BIN_UTILS_H_