From 5b452293d6055754bf007582c5a151a9ad859ede Mon Sep 17 00:00:00 2001
From: Berkan Diler <b.diler@gmx.de>
Date: Sat, 8 Feb 2020 18:05:27 +0100
Subject: [PATCH] Minor cleanups for legacy beatmap decoders

Replaces some string.StartsWith(string, StringComparison.Ordinal) calls with ring.StartsWith(char) , when only one char is compared. Possible since .NET-Standard 2.1

And another LegacyStoryboardDecoder.handleEvents() cleanup, saves some MB of allocations.
---
 osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs    |  2 +-
 osu.Game/Beatmaps/Formats/LegacyDecoder.cs           |  2 +-
 osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs | 11 ++++++-----
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
index 009da0656b..4b01b2490e 100644
--- a/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs
@@ -64,7 +64,7 @@ namespace osu.Game.Beatmaps.Formats
                 hitObject.ApplyDefaults(this.beatmap.ControlPointInfo, this.beatmap.BeatmapInfo.BaseDifficulty);
         }
 
-        protected override bool ShouldSkipLine(string line) => base.ShouldSkipLine(line) || line.StartsWith(" ", StringComparison.Ordinal) || line.StartsWith("_", StringComparison.Ordinal);
+        protected override bool ShouldSkipLine(string line) => base.ShouldSkipLine(line) || line.StartsWith(' ') || line.StartsWith('_');
 
         protected override void ParseLine(Beatmap beatmap, Section section, string line)
         {
diff --git a/osu.Game/Beatmaps/Formats/LegacyDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
index 0ec80eee41..e28e235788 100644
--- a/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyDecoder.cs
@@ -33,7 +33,7 @@ namespace osu.Game.Beatmaps.Formats
                 if (ShouldSkipLine(line))
                     continue;
 
-                if (line.StartsWith(@"[", StringComparison.Ordinal) && line.EndsWith(@"]", StringComparison.Ordinal))
+                if (line.StartsWith('[') && line.EndsWith(']'))
                 {
                     if (!Enum.TryParse(line[1..^1], out section))
                     {
diff --git a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
index 35576e0f33..6569f76b2d 100644
--- a/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
+++ b/osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs
@@ -64,15 +64,16 @@ namespace osu.Game.Beatmaps.Formats
         private void handleEvents(string line)
         {
             var depth = 0;
-            var lineSpan = line.AsSpan();
 
-            while (lineSpan.StartsWith(" ", StringComparison.Ordinal) || lineSpan.StartsWith("_", StringComparison.Ordinal))
+            foreach (char c in line)
             {
-                lineSpan = lineSpan.Slice(1);
-                ++depth;
+                if (c == ' ' || c == '_')
+                    depth++;
+                else
+                    break;
             }
 
-            line = lineSpan.ToString();
+            line = line.Substring(depth);
 
             decodeVariables(ref line);