SepReader.Cols: Add CombinePathsToString (net9.0+ only due to Path.Co…

…mbine(Span<>) only) (#253)
nietras · Jan 31, 2025 · 8429e4f · 8429e4f
1 parent 985457a
commit 8429e4f
Show file tree

Hide file tree

Showing 4 changed files with 43 additions and 0 deletions.
diff --git a/README.md b/README.md
@@ -2068,6 +2068,7 @@ namespace nietras.SeparatedValues
         {
             public int Count { get; }
             public nietras.SeparatedValues.SepReader.Col this[int index] { get; }
+            public string CombinePathsToString() { }
             public System.ReadOnlySpan<char> Join(System.ReadOnlySpan<char> separator) { }
             public string JoinToString(System.ReadOnlySpan<char> separator) { }
             public System.Span<T> Parse<T>()

diff --git a/src/Sep.Test/SepReaderColsTest.cs b/src/Sep.Test/SepReaderColsTest.cs
@@ -1,5 +1,8 @@
 using System;
 using System.Collections.Generic;
+#if NET9_0_OR_GREATER
+using System.IO;
+#endif
 using System.Linq;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -190,6 +193,14 @@ public void SepReaderColsTest_Join(string separator)
         Run((cols, range) => Assert.AreEqual(string.Join(separator, _colTexts[range]), cols.JoinToString(separator)));
     }
 
+#if NET9_0_OR_GREATER
+    [TestMethod]
+    public void SepReaderColsTest_CombinePathsToString()
+    {
+        Run((cols, range) => Assert.AreEqual(Path.Combine(_colTexts[range]), cols.CombinePathsToString()));
+    }
+#endif
+
     static string ToString(SepReader.Col col) => col.ToString();
 
     static void Run(ColsTestAction action, string text = Text, bool checkIndexOutOfRange = true)

diff --git a/src/Sep/SepReader.Cols.cs b/src/Sep/SepReader.Cols.cs
@@ -111,6 +111,12 @@ public string JoinToString(ReadOnlySpan<char> separator) => IsIndices()
             ? _state.JoinToString(_colIndices, separator)
             : _state.JoinToString(_colStartIfRange, _colIndices.Length, separator);
 
+#if NET9_0_OR_GREATER
+        public string CombinePathsToString() => IsIndices()
+            ? _state.CombinePathsToString(_colIndices)
+            : _state.CombinePathsToString(_colStartIfRange, _colIndices.Length);
+#endif
+
         bool IsIndices() => _colStartIfRange < 0;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

diff --git a/src/Sep/SepReaderState.cs b/src/Sep/SepReaderState.cs
@@ -2,6 +2,9 @@
 using System.Buffers;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+#if NET9_0_OR_GREATER
+using System.IO;
+#endif
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using static nietras.SeparatedValues.SepReader;
@@ -704,6 +707,17 @@ internal string JoinToString(ReadOnlySpan<int> colIndices, scoped ReadOnlySpan<c
         return JoinToString(colRanges, separator);
     }
 
+#if NET9_0_OR_GREATER
+    [SkipLocalsInit]
+    internal string CombinePathsToString(ReadOnlySpan<int> colIndices)
+    {
+        if (colIndices.Length == 0) { return string.Empty; }
+        if (colIndices.Length == 1) { return ToStringDefault(colIndices[0]); }
+        var paths = ToStrings(colIndices);
+        return Path.Combine(paths);
+    }
+#endif
+
     void GetColRanges(ReadOnlySpan<int> colIndices, Span<SepRange> colRanges)
     {
         A.Assert(colIndices.Length == colRanges.Length);
@@ -824,6 +838,17 @@ internal string JoinToString(int colStart, int colCount, scoped ReadOnlySpan<cha
         return JoinToString(colRanges, separator);
     }
 
+#if NET9_0_OR_GREATER
+    [SkipLocalsInit]
+    internal string CombinePathsToString(int colStart, int colCount)
+    {
+        if (colCount == 0) { return string.Empty; }
+        if (colCount == 1) { return ToStringDefault(colStart); }
+        var paths = ToStrings(colStart, colCount);
+        return Path.Combine(paths);
+    }
+#endif
+
     void GetColRanges(int colStart, Span<SepRange> colRanges)
     {
         for (var i = 0; i < colRanges.Length; i++)