Merge pull request #108 from greymistcube/refactor/text-equality

Streamline `Text` equality and comparison

Bencodex.Tests/Types/TextTest.cs

@@ -1,3 +1,4 @@
+using System;
 using Bencodex.Types;
 using Xunit;
 using static Bencodex.Misc.ImmutableByteArrayExtensions;
@@ -19,6 +20,69 @@ public void Kind()
             Assert.Equal(ValueKind.Text, _complex.Kind);
         }
 
+        [Fact]
+        public void Equality()
+        {
+            string s = "foo";
+            Text t = new Text("foo");
+            object os = (object)s;
+            object ot = (object)t;
+
+#pragma warning disable CS1718 // Comparison made to same variable
+            Assert.True(t == t);
+            Assert.True(t.Equals(t));
+            Assert.True(t.Equals(ot));
+            Assert.True(ot.Equals(t));
+            Assert.True(ot.Equals(ot));
+#pragma warning restore CS1718
+
+            Assert.True(s == t);
+            Assert.True(t == s);
+            Assert.True(s.Equals(t));
+            Assert.True(t.Equals(t));
+
+            Assert.False(s.Equals(ot));
+            Assert.False(t.Equals(os));
+            Assert.False(os.Equals(t));
+            Assert.False(ot.Equals(s));
+            Assert.False(os.Equals(ot));
+            Assert.False(ot.Equals(os));
+        }
+
+        [Fact]
+        public void Comparison()
+        {
+            string s = "foo";
+            Text t = new Text("foo");
+            Text? n = null;
+            object os = (object)s;
+            object ot = (object)t;
+            object on = null;
+
+            Assert.Equal(0, t.CompareTo(t));
+            Assert.Equal(0, t.CompareTo(ot));
+            Assert.Equal(1, t.CompareTo(n));
+            Assert.Equal(1, t.CompareTo(on));
+
+            Assert.Equal(0, s.CompareTo(t));
+            Assert.Equal(0, t.CompareTo(s));
+
+            Assert.Throws<ArgumentException>(() => s.CompareTo(ot));
+            Assert.Throws<ArgumentException>(() => t.CompareTo(os));
+
+            Text t0 = new Text("0");
+            Text t1 = new Text("1");
+            Text t00 = new Text("00");
+
+            Assert.Equal(0, t0.CompareTo(t0));
+            Assert.True(t0.CompareTo(t1) < 0);
+            Assert.True(t1.CompareTo(t0) > 0);
+            Assert.True(t0.CompareTo(t00) < 0);
+            Assert.True(t00.CompareTo(t0) > 0);
+            Assert.True(t1.CompareTo(t00) > 0);
+            Assert.True(t00.CompareTo(t1) < 0);
+        }
+
         [Fact]
         public void EncodingLength()
         {

Bencodex/Types/Text.cs

@@ -10,9 +10,7 @@ namespace Bencodex.Types
     public struct Text :
         IKey,
         IEquatable<Text>,
-        IComparable<string>,
         IComparable<Text>,
-        IEquatable<string>,
         IComparable
     {
         private int? _utf8Length;
@@ -91,72 +89,47 @@ public static implicit operator Text(string s)
             return new Text(s);
         }
 
-        public static bool operator ==(Text left, Text right)
-        {
-            return left.Equals(right);
-        }
+        public static bool operator ==(Text left, Text right) => left.Equals(right);
 
-        public static bool operator !=(Text left, Text right)
-        {
-            return !left.Equals(right);
-        }
+        public static bool operator !=(Text left, Text right) => !left.Equals(right);
 
-        bool IEquatable<string>.Equals(string other)
-        {
-            return other != null && Value.Equals(other);
-        }
+        public static bool operator ==(Text left, string right) => left.Equals(right);
 
-        bool IEquatable<Text>.Equals(Text other) => Value.Equals(other);
+        public static bool operator !=(Text left, string right) => !left.Equals(right);
 
-        bool IEquatable<IValue>.Equals(IValue other) =>
-            other is Text o && ((IEquatable<Text>)this).Equals(o);
+        public static bool operator ==(string left, Text right) => left.Equals(right.Value);
 
-        public override bool Equals(object obj)
-        {
-            switch (obj)
-            {
-                case null:
-                    return false;
-                case Text txt:
-                    return ((IEquatable<Text>)this).Equals(txt);
-                case string str:
-                    return ((IEquatable<string>)this).Equals(str);
-                default:
-                    return false;
-            }
-        }
+        public static bool operator !=(string left, Text right) => !left.Equals(right.Value);
 
-        public override int GetHashCode()
-        {
-            return Value?.GetHashCode() ?? 0;
-        }
+        public bool Equals(IValue other) => other is Text t && Equals(t);
+
+        public bool Equals(Text other) => Value.Equals(other);
+
+        public override bool Equals(object obj) => obj is Text t && Equals(t);
 
-        int IComparable<string>.CompareTo(string other)
+        public override int GetHashCode()
         {
-            return string.Compare(Value, other, StringComparison.Ordinal);
+            return Value.GetHashCode();
         }
 
-        int IComparable<Text>.CompareTo(Text other)
+        public int CompareTo(Text other)
         {
             return string.Compare(Value, other.Value, StringComparison.Ordinal);
         }
 
-        public int CompareTo(object obj)
+        public int CompareTo(object? obj)
         {
-            switch (obj)
+            if (obj is null)
             {
-                case null:
-                    return 1;
-                case Text txt:
-                    return ((IComparable<Text>)this).CompareTo(txt);
-                case string str:
-                    return ((IComparable<string>)this).CompareTo(str);
-                default:
-                    throw new ArgumentException(
-                        "the argument is neither Text nor String",
-                        nameof(obj)
-                    );
+                return 1;
             }
+
+            if (obj is Text t)
+            {
+                return CompareTo(t);
+            }
+
+            throw new ArgumentException($"Object must be of type {nameof(Text)}");
         }
 
         /// <inheritdoc cref="IValue.Inspect(bool)"/>

CHANGES.md

@@ -10,11 +10,14 @@ To be released.
     `Integer`.  [[#104], [#107]]
  -  Changed the behaviors of `Integer.Equals()` and `Integer.CompareTo()`
     to be more consistent.  [[#106], [#107]]
+ -  Removed `IEquatable<string>` and `IComparable<string>` from `Text`.
+    [[#104], [#108]]
  -  Removed `CompositeComparer<TA, TB>` struct.  [[#109]]
 
 [#104]: https://github.com/planetarium/bencodex.net/issues/104
 [#106]: https://github.com/planetarium/bencodex.net/issues/106
 [#107]: https://github.com/planetarium/bencodex.net/pull/107
+[#108]: https://github.com/planetarium/bencodex.net/pull/108
 [#109]: https://github.com/planetarium/bencodex.net/pull/109