Merge pull request #878 from atravita-mods/develop

Rewrite asset name comparison to stop at the first mismatch

1 files changed, 70 insertions, 0 deletions

diff --git a/src/SMAPI/Utilities/AssetPathUtilities/AssetNamePartEnumerator.cs b/src/SMAPI/Utilities/AssetPathUtilities/AssetNamePartEnumerator.cs
new file mode 100644
index 00000000..11987ed6
--- /dev/null
+++ b/src/SMAPI/Utilities/AssetPathUtilities/AssetNamePartEnumerator.cs
@@ -0,0 +1,70 @@
+using System;
+using ToolkitPathUtilities = StardewModdingAPI.Toolkit.Utilities.PathUtilities;
+
+namespace StardewModdingAPI.Utilities.AssetPathUtilities
+{
+    /// <summary>Handles enumerating the normalized segments in an asset name.</summary>
+    internal ref struct AssetNamePartEnumerator
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The backing field for <see cref="Remainder"/>.</summary>
+        private ReadOnlySpan<char> RemainderImpl;
+
+
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The remainder of the asset name being enumerated, ignoring segments which have already been yielded.</summary>
+        public ReadOnlySpan<char> Remainder => this.RemainderImpl;
+
+        /// <summary>Get the current segment.</summary>
+        public ReadOnlySpan<char> Current { get; private set; } = default;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="assetName">The asset name to enumerate.</param>
+        public AssetNamePartEnumerator(ReadOnlySpan<char> assetName)
+        {
+            this.RemainderImpl = AssetNamePartEnumerator.TrimLeadingPathSeparators(assetName);
+        }
+
+        /// <summary>Move the enumerator to the next segment.</summary>
+        /// <returns>Returns true if a new value was found (accessible via <see cref="Current"/>).</returns>
+        public bool MoveNext()
+        {
+            if (this.RemainderImpl.Length == 0)
+                return false;
+
+            int index = this.RemainderImpl.IndexOfAny(ToolkitPathUtilities.PossiblePathSeparators);
+
+            // no more separator characters found, I'm done.
+            if (index < 0)
+            {
+                this.Current = this.RemainderImpl;
+                this.RemainderImpl = ReadOnlySpan<char>.Empty;
+                return true;
+            }
+
+            // Yield the next separate character bit
+            this.Current = this.RemainderImpl[..index];
+            this.RemainderImpl = AssetNamePartEnumerator.TrimLeadingPathSeparators(this.RemainderImpl[(index + 1)..]);
+            return true;
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Trim path separators at the start of the given path or segment.</summary>
+        /// <param name="span">The path or segment to trim.</param>
+        private static ReadOnlySpan<char> TrimLeadingPathSeparators(ReadOnlySpan<char> span)
+        {
+            return span.TrimStart(new ReadOnlySpan<char>(ToolkitPathUtilities.PossiblePathSeparators));
+        }
+    }
+}