forked from cgvr/DeltaVR
124 lines
3.5 KiB
C#
124 lines
3.5 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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namespace Asset_Cleaner {
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readonly struct Option<T> : IEquatable<Option<T>>, IComparable<Option<T>> {
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// ReSharper disable once StaticMemberInGenericType
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static readonly bool IsValueType;
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public bool HasValue { get; }
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T Value { get; }
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public static implicit operator Option<T>(T arg) {
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if (!IsValueType) return ReferenceEquals(arg, null) ? new Option<T>() : new Option<T>(arg, true);
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#if M_WARN
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if (arg.Equals(default(T)))
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Warn.Warning($"{arg} has default value");
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#endif
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return new Option<T>(arg, true);
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}
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static Option() {
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IsValueType = typeof(T).IsValueType;
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}
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public void GetOrFail(out T value) {
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if (!TryGet(out value))
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Fail($"Option<{typeof(T).Name}> has no value");
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}
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public T GetOrFail() {
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if (!TryGet(out var value))
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Fail($"Option<{typeof(T).Name}> has no value");
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return value;
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}
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[Conditional("DEBUG1")]
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static void Fail(string format = null) {
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throw new Exception(format);
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}
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public bool TryGet(out T value) {
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if (!HasValue) {
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value = default(T);
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return false;
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}
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value = Value;
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return true;
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}
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internal Option(T value, bool hasValue) {
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Value = value;
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HasValue = hasValue;
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}
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public T ValueOr(T alternative) {
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return HasValue ? Value : alternative;
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}
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// for debug purposes
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public override string ToString() {
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if (!HasValue) return "None";
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return Value == null ? "Some(null)" : $"Some({Value})";
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}
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#region eq comparers boilerplate
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public bool Equals(Option<T> other) {
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if (!HasValue && !other.HasValue)
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return true;
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if (HasValue && other.HasValue)
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return EqualityComparer<T>.Default.Equals(Value, other.Value);
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return false;
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}
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public override bool Equals(object obj) {
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return obj is Option<T> && Equals((Option<T>) obj);
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}
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public static bool operator ==(Option<T> left, Option<T> right) {
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return left.Equals(right);
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}
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public static bool operator !=(Option<T> left, Option<T> right) {
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return !left.Equals(right);
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}
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public override int GetHashCode() {
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if (!HasValue) return 0;
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return IsValueType || Value != null ? Value.GetHashCode() : 1;
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}
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public int CompareTo(Option<T> other) {
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if (HasValue && !other.HasValue) return 1;
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if (!HasValue && other.HasValue) return -1;
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return Comparer<T>.Default.Compare(Value, other.Value);
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}
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public static bool operator <(Option<T> left, Option<T> right) {
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return left.CompareTo(right) < 0;
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}
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public static bool operator <=(Option<T> left, Option<T> right) {
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return left.CompareTo(right) <= 0;
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}
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public static bool operator >(Option<T> left, Option<T> right) {
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return left.CompareTo(right) > 0;
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}
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public static bool operator >=(Option<T> left, Option<T> right) {
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return left.CompareTo(right) >= 0;
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}
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#endregion
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}
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} |