feat: PadLeft and PadRight

Author: linkdotnet

CHANGELOG.md

@@ -6,6 +6,9 @@ All notable changes to **ValueStringBuilder** will be documented in this file. T
 
 ## [Unreleased]
 
+### Added
+- `PadLeft` and `PadRight` methods
+
 ## [1.20.0] - 2024-05-02
 
 ### Added

src/LinkDotNet.StringBuilder/ValueStringBuilder.Pad.cs

@@ -0,0 +1,42 @@
+namespace LinkDotNet.StringBuilder;
+
+public ref partial struct ValueStringBuilder
+{
+    /// <summary>
+    /// Pads the left side of the string with the given character.
+    /// </summary>
+    /// <param name="totalWidth">Total width of the string after padding.</param>
+    /// <param name="paddingChar">Character to pad the string with.</param>
+    public void PadLeft(int totalWidth, char paddingChar)
+    {
+        if (totalWidth <= bufferPosition)
+        {
+            return;
+        }
+
+        EnsureCapacity(totalWidth);
+
+        var padding = totalWidth - bufferPosition;
+        buffer[..bufferPosition].CopyTo(buffer[padding..]);
+        buffer[..padding].Fill(paddingChar);
+        bufferPosition = totalWidth;
+    }
+
+    /// <summary>
+    /// Pads the right side of the string with the given character.
+    /// </summary>
+    /// <param name="totalWidth">Total width of the string after padding.</param>
+    /// <param name="paddingChar">Character to pad the string with.</param>
+    public void PadRight(int totalWidth, char paddingChar)
+    {
+        if (totalWidth <= bufferPosition)
+        {
+            return;
+        }
+
+        EnsureCapacity(totalWidth);
+
+        buffer[bufferPosition..totalWidth].Fill(paddingChar);
+        bufferPosition = totalWidth;
+    }
+}

tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilder.Pad.Tests.cs

@@ -0,0 +1,44 @@
+namespace LinkDotNet.StringBuilder.UnitTests;
+
+public class ValueStringBuilderPadTests
+{
+    [Fact]
+    public void ShouldPadLeft()
+    {
+        using var stringBuilder = new ValueStringBuilder("Hello");
+
+        stringBuilder.PadLeft(10, ' ');
+
+        stringBuilder.ToString().Should().Be("     Hello");
+    }
+
+    [Fact]
+    public void ShouldPadRight()
+    {
+        using var stringBuilder = new ValueStringBuilder("Hello");
+
+        stringBuilder.PadRight(10, ' ');
+
+        stringBuilder.ToString().Should().Be("Hello     ");
+    }
+
+    [Fact]
+    public void GivenTotalWidthIsSmallerThanCurrentLength_WhenPadLeft_ThenShouldNotChange()
+    {
+        using var stringBuilder = new ValueStringBuilder("Hello");
+
+        stringBuilder.PadLeft(3, ' ');
+
+        stringBuilder.ToString().Should().Be("Hello");
+    }
+
+    [Fact]
+    public void GivenTotalWidthIsSmallerThanCurrentLength_WhenPadRight_ThenShouldNotChange()
+    {
+        using var stringBuilder = new ValueStringBuilder("Hello");
+
+        stringBuilder.PadRight(3, ' ');
+
+        stringBuilder.ToString().Should().Be("Hello");
+    }
+}