public void GetHashCode_ReturnsDifferentHashCodes_ForDifferentArrays()
{
var r1 = _comparer.GetHashCode(new[] { 1, 2, 3 });
var r2 = _comparer.GetHashCode(new[] { 1, 2, 4 });
Assert.AreNotEqual(r1, r2);
}
static void Main()
{
byte[] x = { 1, 2, 3 };
byte[] y = { 1, 2, 3 };
byte[] z = { 4, 5, 6 };
var comparer = new ArrayEqualityComparer <byte>();
Console.WriteLine(comparer.GetHashCode(x));
Console.WriteLine(comparer.GetHashCode(y));
Console.WriteLine(comparer.GetHashCode(z));
Console.WriteLine(comparer.Equals(x, y));
Console.WriteLine(comparer.Equals(x, z));
}
public void ArrayEqualityComparerGetHashCodeReturnsDefaultHashCodeIfArrayIsEmpty()
{
const int expectedHashCode = 23;
var comparer = new ArrayEqualityComparer <int>();
int[] array = new int[0];
int result = comparer.GetHashCode(array);
Assert.AreEqual(expectedHashCode, result);
}
public void ArrayEqualityComparerGetHashCodeReturnsZeroIfArrayIsNull()
{
const int expectedHashCode = 0;
var comparer = new ArrayEqualityComparer <int>();
int[] array = null;
int result = comparer.GetHashCode(array);
Assert.AreEqual(expectedHashCode, result);
}
static void Main(string[] args)
{
int[] x = { 1, 2, 3 };
int[] y = { 1, 2, 3 };
int[] z = { 4, 5, 6 };
var comparer = new ArrayEqualityComparer <int>();
Console.WriteLine(comparer.GetHashCode(x));
Console.WriteLine(comparer.GetHashCode(y));
Console.WriteLine(comparer.GetHashCode(z));
Console.WriteLine(comparer.Equals(x, y));
Console.WriteLine(comparer.Equals(x, z));
Console.WriteLine();
Console.WriteLine("Byte comparers");
byte[] x1 = { 1, 2, 3 };
byte[] y1 = { 1, 2, 3 };
byte[] z1 = { 4, 5, 6 };
var comparer1 = new ByteArrayEqualityComparer();
Console.WriteLine(comparer1.GetHashCode(x1));
Console.WriteLine(comparer1.GetHashCode(y1));
Console.WriteLine(comparer1.GetHashCode(z1));
Console.WriteLine(comparer1.Equals(x1, y1));
Console.WriteLine(comparer1.Equals(x1, z1));
var t = new Dictionary <byte[], string>(comparer1);
t.Add(x1, "x");
t.Add(z1, "z");
Console.WriteLine($"t[y] = {t[y1]} ");
Console.WriteLine("Press [Enter] for continue ...");
Console.ReadLine();
}
public void ArrayEqualityComparerGetHashCodeReturnsSameHashCodeIfArrayContainsNullElements()
{
var comparer = new ArrayEqualityComparer <int?>();
int?[] array = new int?[] { 1, 2, null, 4, 5 };
//get the HashCode 2000 times to confirm it is consistent for lifetime of the array
HashSet <int> hashes = new HashSet <int>();
for (int i = 0; i < 2000; i++)
{
hashes.Add(comparer.GetHashCode(array));
}
Assert.AreEqual(1, hashes.Count);
}
public static int GetArrayHashCode <T> (this T[] array)
{
return(ArrayEqualityComparer <T> .GetHashCode(array));
}
public override int GetHashCode()
{
return(DataComparer.GetHashCode(_data));
}