public static bool ContainsRange <T>(this SCG.IEnumerable <T> first, SCG.IEnumerable <T> second, SCG.IEqualityComparer <T> equalityComparer = null)
{
#region Code Contracts
// Argument must be non-null
Requires(first != null, ArgumentMustBeNonNull);
// Argument must be non-null
Requires(second != null, ArgumentMustBeNonNull);
// first remains unchanged
Ensures(first == null || first.IsSameSequenceAs(OldValue(first.ToList())));
// second remains unchanged
Ensures(second == null || second.IsSameSequenceAs(OldValue(second.ToList())));
#endregion
var firstArray = first.ToArray();
var secondArray = second.ToArray();
if (firstArray.Length < secondArray.Length)
{
return(false);
}
// Use default comparer if none is supplied
if (equalityComparer == null)
{
equalityComparer = SCG.EqualityComparer <T> .Default;
}
// Sort based on hash code
Comparison <T> hashCodeComparison = (x, y) => equalityComparer.GetHashCode(x).CompareTo(equalityComparer.GetHashCode(y));
Array.Sort(firstArray, hashCodeComparison);
Array.Sort(secondArray, hashCodeComparison);
for (var j = 0; j < secondArray.Length; j++)
{
var found = false;
var secondElement = secondArray[j];
for (var i = j; i < firstArray.Length; i++)
{
var firstElement = firstArray[i];
var comparison = hashCodeComparison(firstElement, secondElement);
// Equal doesn't exist
if (comparison > 0)
{
break;
}
if (comparison == 0 && equalityComparer.Equals(firstElement, secondElement))
{
firstArray.Swap(i, j);
// TODO: the hash codes are not necessarily ordered after swapping the items
found = true;
break;
}
}
if (!found)
{
return(false);
}
// Invariant: all items up to and including j are equal pairwise in the two arrays
Assume(ForAll(0, j + 1, i => equalityComparer.Equals(firstArray[i], secondArray[i])));
}
return(true);
}
public static bool UnsequenceEqual <T>(this SCG.IEnumerable <T> first, SCG.IEnumerable <T> second, SCG.IEqualityComparer <T> comparer = null)
{
#region Code Contracts
// first remains unchanged
Ensures(first == null || first.IsSameSequenceAs(OldValue(first.ToList())));
// second remains unchanged
Ensures(second == null || second.IsSameSequenceAs(OldValue(second.ToList())));
#endregion
if (ReferenceEquals(first, second))
{
return(true);
}
if (first == null || second == null)
{
return(false);
}
var firstArray = first.ToArray();
var secondArray = second.ToArray();
if (firstArray.Length != secondArray.Length)
{
return(false);
}
// Use default comparer if none is supplied
if (comparer == null)
{
comparer = SCG.EqualityComparer <T> .Default;
}
// Sort based on hash code
Comparison <T> hashCodeComparison = (x, y) => comparer.GetHashCode(x).CompareTo(comparer.GetHashCode(y));
Array.Sort(firstArray, hashCodeComparison);
Array.Sort(secondArray, hashCodeComparison);
for (var i = 0; i < firstArray.Length; i++)
{
var found = false;
var firstElement = firstArray[i];
for (var j = i; j < secondArray.Length; j++)
{
var secondElement = secondArray[j];
if (hashCodeComparison(firstElement, secondElement) != 0)
{
break;
}
if (comparer.Equals(firstElement, secondElement))
{
secondArray.Swap(i, j);
// Continue with next element in first array
found = true;
break;
}
}
if (!found)
{
return(false);
}
}
return(true);
}
