feat: add humanize and pascalize string exts

backend/Naninovel.Common.Modern/Utilities/TextUtils.cs

@@ -0,0 +1,63 @@
+namespace Naninovel;
+
+/// <summary>
+/// Common text-related helpers and extensions.
+/// </summary>
+public static class TextUtils
+{
+    /// <summary>
+    /// Formats specified string for human readability by removing non-letter and
+    /// non-digit characters and converting from snake_case, PascalCase, camelCase,
+    /// kebab-case or SCREAMING_CASE to Title Case.
+    /// </summary>
+    public static string Humanize (this string str)
+    {
+        int idx, length = 0;
+        char curr, prev, next, last = default;
+        Span<char> buffer = stackalloc char[str.Length * 2];
+
+        for (idx = 0; idx < str.Length; idx++)
+        {
+            curr = str[idx];
+            prev = idx > 0 ? str[idx - 1] : default;
+            next = idx + 1 < str.Length ? str[idx + 1] : default;
+            last = length > 0 ? buffer[length - 1] : default;
+            if (!Skip()) buffer[length++] = Upper() ? char.ToUpper(curr) : Lower() ? char.ToLower(curr) : curr;
+            if (Space()) buffer[length++] = ' ';
+        }
+
+        return buffer[..length].ToString();
+
+        bool Skip () => !char.IsLetterOrDigit(curr);
+        bool Upper () => length == 1 || char.IsWhiteSpace(last);
+        bool Lower () => char.IsUpper(curr) && char.IsUpper(prev);
+        bool Space () => length > 0 && (
+            char.IsLower(curr) && char.IsUpper(next) ||
+            char.IsLetter(curr) && char.IsDigit(next) ||
+            char.IsDigit(curr) && char.IsLetter(next) ||
+            !char.IsLetterOrDigit(curr) && char.IsLetterOrDigit(next));
+    }
+
+    /// <summary>
+    /// Converts specified string to PascalCase.
+    /// </summary>
+    public static string ToPascalCase (this string str)
+    {
+        int idx, length = 0;
+        char curr, prev = default;
+        Span<char> buffer = stackalloc char[str.Length];
+
+        for (idx = 0; idx < str.Length; idx++)
+        {
+            curr = str[idx];
+            prev = idx > 0 ? str[idx - 1] : default;
+            if (!Skip()) buffer[length++] = Upper() ? char.ToUpper(curr) : Lower() ? char.ToLower(curr) : curr;
+        }
+
+        return buffer[..length].ToString();
+
+        bool Skip () => !char.IsLetterOrDigit(curr);
+        bool Upper () => length == 1 || !char.IsLetterOrDigit(prev);
+        bool Lower () => char.IsUpper(curr) && char.IsUpper(prev);
+    }
+}

backend/Naninovel.Common.Test/Utilities/TextUtilsTest.cs

@@ -206,4 +206,56 @@ public void SanitizeWorksCorrectly (string input, IReadOnlyCollection<char> inva
     {
         Assert.Equal(expected, input.Sanitize(invalid));
     }
+
+    [Theory]
+    [InlineData("", "")]
+    [InlineData(" ", "")]
+    [InlineData("_-\\+^@", "")]
+    [InlineData("FooBar", "Foo Bar")]
+    [InlineData("fooBar", "Foo Bar")]
+    [InlineData("foo_bar", "Foo Bar")]
+    [InlineData("FOO_BAR", "Foo Bar")]
+    [InlineData("FOO BAR", "Foo Bar")]
+    [InlineData("foo-bar", "Foo Bar")]
+    [InlineData("Foo Bar", "Foo Bar")]
+    [InlineData("Foo1", "Foo 1")]
+    [InlineData("Foo 1", "Foo 1")]
+    [InlineData("Foo123Bar321Nya", "Foo 123 Bar 321 Nya")]
+    [InlineData("Foo 123Bar", "Foo 123 Bar")]
+    [InlineData(" Foo 123 Bar ", "Foo 123 Bar")]
+    [InlineData("Foo-123_Bar", "Foo 123 Bar")]
+    [InlineData("_foo_", "Foo")]
+    [InlineData("__foo__", "Foo")]
+    [InlineData("___foo___", "Foo")]
+    [InlineData(" _ __ FOO1-2-3BAR __ _ ", "Foo 1 2 3 Bar")]
+    public void HumanizeWorksCorrectly (string input, string expected)
+    {
+        Assert.Equal(expected, input.Humanize());
+    }
+
+    [Theory]
+    [InlineData("", "")]
+    [InlineData(" ", "")]
+    [InlineData("_-\\+^@", "")]
+    [InlineData("FooBar", "FooBar")]
+    [InlineData("fooBar", "FooBar")]
+    [InlineData("foo_bar", "FooBar")]
+    [InlineData("FOO_BAR", "FooBar")]
+    [InlineData("FOO BAR", "FooBar")]
+    [InlineData("foo-bar", "FooBar")]
+    [InlineData("Foo Bar", "FooBar")]
+    [InlineData("Foo1", "Foo1")]
+    [InlineData("Foo 1", "Foo1")]
+    [InlineData("Foo 123 Bar 321 Nya", "Foo123Bar321Nya")]
+    [InlineData("Foo 123Bar", "Foo123Bar")]
+    [InlineData(" Foo 123 Bar ", "Foo123Bar")]
+    [InlineData("Foo-123_Bar", "Foo123Bar")]
+    [InlineData("_foo_", "Foo")]
+    [InlineData("__foo__", "Foo")]
+    [InlineData("___foo___", "Foo")]
+    [InlineData(" _ __ FOO1-2-3BAR __ _ ", "Foo123Bar")]
+    public void ToPascalCaseWorksCorrectly (string input, string expected)
+    {
+        Assert.Equal(expected, input.ToPascalCase());
+    }
 }