/// <summary>
/// Converts the given comparison function to a comparer object.
/// </summary>
/// <typeparam name="T">The type of the items that are compared.</typeparam>
/// <param name="comparison">The comparison function to convert.</param>
/// <returns>A new comparer that wraps the comparison function.</returns>
/// <exception cref="System.ArgumentNullException">The comparison function is null.</exception>
public static IComparer <T> ToComparer <T>(this Func <T, T, int> comparison)
{
if (comparison is null)
{
throw new ArgumentNullException(nameof(comparison));
}
return(ComparisonWrapper <T> .GetComparer(comparison));
}
/// <summary>
/// Creates a new KeyComparer that sorts using the results of the key selector.
/// </summary>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="keySelector">A function that selects a key.</param>
/// <param name="keyComparison">The comparison delegate to use to compare keys.</param>
/// <returns>A KeyComparer using the key selector.</returns>
/// <exception cref="System.ArgumentNullException">The key selector is null.</exception>
/// <exception cref="System.ArgumentNullException">The key comparison delegate is null.</exception>
public static KeyComparer <T> OrderBy <TKey>(Func <T, TKey> keySelector, Func <TKey, TKey, int> keyComparison)
{
if (keySelector == null)
{
throw new ArgumentNullException("keySelector");
}
if (keyComparison == null)
{
throw new ArgumentNullException("keyComparison");
}
IComparer <TKey> keyComparer = ComparisonWrapper <TKey> .GetComparer(keyComparison);
return(new TypedKeyComparer <T, TKey>(keySelector, keyComparer));
}
/// <summary>
/// Composes a comparer that performs subsequent ordering using the comparison.
/// </summary>
/// <typeparam name="T">The type being compared.</typeparam>
/// <param name="baseComparer">The comparer to extend.</param>
/// <param name="comparison">The comparison to use if two items compare as equal using the base comparer.</param>
/// <returns>A comparer that performs comparisons using both comparison operations.</returns>
/// <exception cref="System.ArgumentNullException">The base comparer is null.</exception>
/// <exception cref="System.ArgumentNullException">The comparison delegate is null.</exception>
public static IComparer <T> ThenBy <T>(this IComparer <T> baseComparer, Func <T, T, int> comparison)
{
if (baseComparer is null)
{
throw new ArgumentNullException(nameof(baseComparer));
}
if (comparison is null)
{
throw new ArgumentNullException(nameof(comparison));
}
var wrapper = ComparisonWrapper <T> .GetComparer(comparison);
var compoundComparer = CompoundComparer <T> .GetComparer(baseComparer, wrapper);
return(compoundComparer);
}
/// <summary>
/// Composes a comparer that performs subsequent ordering using the comparison.
/// </summary>
/// <typeparam name="T">The type being compared.</typeparam>
/// <param name="baseComparer">The comparer to extend.</param>
/// <param name="comparison">The comparison to use if two items compare as equal using the base comparer.</param>
/// <returns>A comparer that performs comparisons using both comparison operations.</returns>
/// <exception cref="System.ArgumentNullException">The base comparer is null.</exception>
/// <exception cref="System.ArgumentNullException">The comparison delegate is null.</exception>
public static IComparer <T> ThenBy <T>(this IComparer <T> baseComparer, Func <T, T, int> comparison)
{
if (baseComparer == null)
{
throw new ArgumentNullException("baseComparer");
}
if (comparison == null)
{
throw new ArgumentNullException("comparison");
}
IComparer <T> wrapper = ComparisonWrapper <T> .GetComparer(comparison);
IComparer <T> compoundComparer = CompoundComparer <T> .GetComparer(baseComparer, wrapper);
return(compoundComparer);
}
/// <summary>
/// Creates a new KeyComparer that sorts using the results of the key selector, in descending order.
/// </summary>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <param name="keySelector">A function that selects a key.</param>
/// <param name="keyComparison">The comparison delegate to use to compare keys.</param>
/// <returns>A KeyComparer using the key selector.</returns>
/// <exception cref="System.ArgumentNullException">The key selector is null.</exception>
/// <exception cref="System.ArgumentNullException">The key comparison delegate is null.</exception>
public static KeyComparer <T> OrderByDescending <TKey>(Func <T, TKey> keySelector,
Func <TKey, TKey, int> keyComparison)
{
if (keySelector == null)
{
throw new ArgumentNullException(nameof(keySelector));
}
if (keyComparison == null)
{
throw new ArgumentNullException(nameof(keyComparison));
}
var keyComparer = ComparisonWrapper <TKey> .GetComparer(keyComparison);
return(new TypedKeyComparer <T, TKey>(keySelector, keyComparer)
{
Descending = true
});
}