/// <summary>
/// hashCode function that properly handles arrays,
/// collections, maps, collections of arrays, and maps of arrays.
/// </summary>
/// <param name="o">The object. May be null.</param>
/// <returns>the hashCode</returns>
public static int GetHashCode(Object o)
{
if (o == null)
{
return(0);
}
else if (o is Array)
{
Array array = (Array)o;
int length = array.Length;
int rv = 0;
for (int i = 0; i < length; i++)
{
Object el = array.GetValue(i);
unchecked
{
rv += CollectionUtil.GetHashCode(el);
}
}
return(rv);
}
else if (ReflectionUtil.IsParentTypeOf(typeof(KeyValuePair <,>), o.GetType()))
{
Type parent = ReflectionUtil.FindInHierarchyOf(typeof(KeyValuePair <,>), o.GetType());
Type[] genericArguments =
parent.GetGenericArguments();
Type collectionUtil = typeof(CollectionUtil);
MethodInfo info = collectionUtil.GetMethod("GetKeyValuePairHashCode");
info = info.MakeGenericMethod(genericArguments);
Object rv = info.Invoke(null, new object[] { o });
return((int)rv);
}
else if (ReflectionUtil.IsParentTypeOf(typeof(ICollection <>), o.GetType()))
{
Type parent = ReflectionUtil.FindInHierarchyOf(typeof(ICollection <>), o.GetType());
Type[] genericArguments =
parent.GetGenericArguments();
Type collectionUtil = typeof(CollectionUtil);
MethodInfo info = collectionUtil.GetMethod("GetEnumerableHashCode");
info = info.MakeGenericMethod(genericArguments);
Object rv = info.Invoke(null, new object[] { o });
return((int)rv);
}
else
{
return(o.GetHashCode());
}
}
/// <summary>
/// Computes a hashCode for a key value pair.
/// </summary>
/// <param name="pair">The pair</param>
/// <returns>The hashcode</returns>
public static int GetKeyValuePairHashCode <K, V>(KeyValuePair <K, V> pair)
{
int rv = 0;
unchecked
{
rv += CollectionUtil.GetHashCode(pair.Key);
rv += CollectionUtil.GetHashCode(pair.Value);
}
return(rv);
}
/// <summary>
/// Computes a hashCode over the enumeration. The hashCode is computed
/// such that it doesn't matter what order the elements are listed in. Thus, it
/// is suitable for arrays, lists, sets, and dictionaries
/// </summary>
/// <param name="enum1">The enumerable</param>
/// <returns>The hashcode</returns>
public static int GetEnumerableHashCode <T>(IEnumerable <T> enum1)
{
if (enum1 == null)
{
return(0);
}
int rv = 0;
foreach (T val1 in enum1)
{
unchecked
{
rv += CollectionUtil.GetHashCode(val1);
}
}
return(rv);
}