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// 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;
}
}
}
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