Merge pull request #51 from snowfrogdev/pvaillancourt/is-acii

Add an IsAscii extension method for string

.gitignore

@@ -348,3 +348,6 @@ MigrationBackup/
 
 # Ionide (cross platform F# VS Code tools) working folder
 .ionide/
+
+# Visual Studio Code configuration files
+.vscode

src/Ardalis.Extensions/StringManipulation/IsAscii.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Linq;
+
+namespace Ardalis.Extensions.StringManipulation;
+
+public static partial class StringManipulationExtensions
+{
+  /// <summary>
+  /// Checks if all characters in this string are within the ASCII range.
+  /// </summary>
+  /// <example>
+  /// <code>
+  /// var ascii = "hello!\n";
+  /// var nonAscii = "Grüße, Jürgen ❤";
+  /// 
+  /// Assert.True(ascii.IsAscii());
+  /// Assert.False(nonAscii.IsAscii());
+  /// </code>
+  /// </example>
+  public static bool IsAscii(this string text)
+  {
+    return text.ToCharArray().All(c => IsAscii(c));
+  }
+
+
+  // Return true for all characters below or equal U+007f, which is ASCII.
+
+  /// <summary>
+  /// Returns <see langword="true"/> if <paramref name="c"/> is an ASCII
+  /// character ([ U+0000..U+007F ]).
+  /// </summary>
+  /// <remarks>
+  /// Per http://www.unicode.org/glossary/#ASCII, ASCII is only U+0000..U+007F.
+  /// </remarks>
+  private static bool IsAscii(char c) => (uint)c <= '\x007F';
+}

tests/Ardalis.Extensions.UnitTests/StringManipulation/IsAsciiTests.cs

@@ -0,0 +1,19 @@
+using Ardalis.Extensions.StringManipulation;
+using Xunit;
+
+namespace Ardalis.Extensions.UnitTests.StringManipulation;
+
+public class IsAsciiTests
+{
+  [Theory]
+  [InlineData("", true)]
+  [InlineData("Hello!\n", true)]
+  [InlineData("banana\0\x7F", true)]
+  [InlineData("Vi\xe1\xbb\x87t Nam", false)]  
+  [InlineData("ประเทศไทย中华Việt Nam", false)]  
+  [InlineData("Grüße, Jürgen ❤", false)]
+  public void ValidatesIfStringIsAscii(string input, bool expected)
+  {
+    Assert.Equal(expected, input.IsAscii());
+  }
+}