void Ctor()
{
IComparer comp = null;
Int32 result = 0;
Test.If.Action.ThrowsException(() => comp = new InternalComparer(null), out ArgumentNullException ex1);
Test.If.Value.IsEqual(ex1.ParamName, "compare");
Test.IfNot.Action.ThrowsException(() => comp = new InternalComparer((x, y) => 42), out Exception ex2);
result = comp.Compare(0, 1);
Test.If.Value.IsEqual(result, 42);
}
/// <summary>
/// Returns a new instance of <see cref="IComparer"/> using the given implementation of <see cref="IComparable"/>.
/// </summary>
/// <typeparam name="T">The type of the objects to compare.</typeparam>
/// <returns>A new instance of <see cref="IComparer"/>.</returns>
public static IComparer FromIComparable <T>()
where T : IComparable
{
Type type = typeof(T);
Object syncRoot = (_cache as ICollection).SyncRoot;
IComparer comparer = null;
lock (syncRoot) {
if (_cache.ContainsKey(type))
{
comparer = _cache[type] as IComparer;
}
}
if (comparer == null)
{
Comparison compare = (x, y) => {
T _x = (T)x;
T _y = (T)y;
if (_x == null && _y == null)
{
return(0);
}
if (_x != null && _y != null)
{
return(_x.CompareTo(_y));
}
return(_x != null ? 1 : -1);
};
comparer = new InternalComparer(compare);
lock (syncRoot) {
if (!_cache.ContainsKey(type))
{
_cache.Add(type, comparer);
}
}
}
return(comparer);
}
/// <summary>
/// Returns a new instance of <see cref="IComparer{T}"/> using the given implementation of <see cref="IComparable{T}"/>.
/// </summary>
/// <typeparam name="T">The type of the objects to compare.</typeparam>
/// <returns>A new instance of <see cref="IComparer{T}"/>.</returns>
public static IComparer <T> FromIComparableT <T>()
where T : IComparable <T>
{
Type type = typeof(T);
Object syncRoot = (_cacheT as ICollection).SyncRoot;
IComparer <T> comparer = null;
lock (syncRoot) {
if (_cacheT.ContainsKey(type))
{
comparer = _cacheT[type] as IComparer <T>;
}
}
if (comparer == null)
{
Comparison <T> compare = (x, y) => {
if (x == null && y == null)
{
return(0);
}
if (x != null && y != null)
{
return(x.CompareTo(y));
}
return(x != null ? 1 : -1);
};
comparer = new InternalComparer <T>(compare);
lock (syncRoot) {
if (!_cacheT.ContainsKey(type))
{
_cacheT.Add(type, comparer);
}
}
}
return(comparer);
}
