// Protocol Buffers - Google's data interchange format // Copyright 2008 Google Inc. All rights reserved. // http://github.com/jskeet/dotnet-protobufs/ // Original C++/Java/Python code: // http://code.google.com/p/protobuf/ // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. using System; using System.Collections; using System.Collections.Generic; namespace Google.ProtocolBuffers.Collections { /// <summary> /// Utility class for dictionaries. /// </summary> public static class Dictionaries { /// <summary> /// Compares two dictionaries for equality. Each value is compared with equality using Equals /// for non-IEnumerable implementations, and using EnumerableEquals otherwise. /// TODO(jonskeet): This is clearly pretty slow, and involves lots of boxing/unboxing... /// </summary> public static bool Equals<TKey, TValue>(IDictionary<TKey, TValue> left, IDictionary<TKey, TValue> right) { if (left.Count != right.Count) { return false; } foreach (KeyValuePair<TKey, TValue> leftEntry in left) { TValue rightValue; if (!right.TryGetValue(leftEntry.Key, out rightValue)) { return false; } IEnumerable leftEnumerable = leftEntry.Value as IEnumerable; IEnumerable rightEnumerable = rightValue as IEnumerable; if (leftEnumerable == null || rightEnumerable == null) { if (!Equals(leftEntry.Value, rightValue)) { return false; } } else { if (!Enumerables.Equals(leftEnumerable, rightEnumerable)) { return false; } } } return true; } public static IDictionary<TKey, TValue> AsReadOnly<TKey, TValue>(IDictionary<TKey, TValue> dictionary) { return dictionary.IsReadOnly ? dictionary : new ReadOnlyDictionary<TKey, TValue>(dictionary); } /// <summary> /// Creates a hashcode for a dictionary by XORing the hashcodes of all the fields /// and values. (By XORing, we avoid ordering issues.) /// TODO(jonskeet): Currently XORs other stuff too, and assumes non-null values. /// </summary> public static int GetHashCode<TKey, TValue>(IDictionary<TKey, TValue> dictionary) { int ret = 31; foreach (KeyValuePair<TKey, TValue> entry in dictionary) { int hash = entry.Key.GetHashCode() ^ GetDeepHashCode(entry.Value); ret ^= hash; } return ret; } /// <summary> /// Determines the hash of a value by either taking it directly or hashing all the elements /// for IEnumerable implementations. /// </summary> private static int GetDeepHashCode(object value) { IEnumerable iterable = value as IEnumerable; if (iterable == null) { return value.GetHashCode(); } int hash = 29; foreach (object element in iterable) { hash = hash*37 + element.GetHashCode(); } return hash; } } }