From b71ea72de9f5640a59cd693ea8169d7741c46006 Mon Sep 17 00:00:00 2001
From: Steven Giesel <stgiesel35@gmail.com>
Date: Fri, 20 Sep 2024 09:17:03 +0200
Subject: [PATCH] feat: PadLeft and PadRight

---
 CHANGELOG.md                                  |  3 ++
 .../ValueStringBuilder.Pad.cs                 | 42 ++++++++++++++++++
 .../ValueStringBuilder.Pad.Tests.cs           | 44 +++++++++++++++++++
 3 files changed, 89 insertions(+)
 create mode 100644 src/LinkDotNet.StringBuilder/ValueStringBuilder.Pad.cs
 create mode 100644 tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilder.Pad.Tests.cs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f75c59e..eaaec3c 100644
--- a/CHANGELOG.md
+++ b/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
diff --git a/src/LinkDotNet.StringBuilder/ValueStringBuilder.Pad.cs b/src/LinkDotNet.StringBuilder/ValueStringBuilder.Pad.cs
new file mode 100644
index 0000000..2a63b7b
--- /dev/null
+++ b/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;
+    }
+}
\ No newline at end of file
diff --git a/tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilder.Pad.Tests.cs b/tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilder.Pad.Tests.cs
new file mode 100644
index 0000000..5c494a5
--- /dev/null
+++ b/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");
+    }
+}
\ No newline at end of file