refactor: 精简代码

Author: ArgoZhang

tools/BootstrapBlazor.CssBundler/Bundler.cs

@@ -3,6 +3,7 @@
 // Website: https://www.blazor.zone or https://argozhang.github.io/
 
 using System.Buffers;
+using System.Text;
 
 namespace BootstrapBlazor.CssBundler;
 
@@ -58,42 +59,33 @@ static void DoBundler(string bundlerFile, BundlerOptions option)
             return;
         }
 
-        var buffer = ArrayPool<byte>.Shared.Rent(64 * 1024);
-        try
+        using var writer = File.OpenWrite(Path.Combine(rootFolder, option.OutputFileName));
+        foreach (var file in option.InputFiles)
         {
-            using var writer = File.OpenWrite(Path.Combine(rootFolder, option.OutputFileName));
-            foreach (var file in option.InputFiles)
+            var inputFile = Path.Combine(rootFolder, file);
+            if (!File.Exists(inputFile))
             {
-                var inputFile = Path.Combine(rootFolder, file);
-                if (!File.Exists(inputFile))
-                {
-                    continue;
-                }
-
-                using var reader = File.OpenRead(inputFile);
-                var read = reader.Read(buffer, 0, buffer.Length);
-                if (read >= 3 && buffer[0] == 0xEF && buffer[1] == 0xBB && buffer[2] == 0xBF)
-                {
-                    writer.Write(buffer, 3, read - 3);
-                }
-                else
-                {
-                    writer.Write(buffer, 0, read);
-                }
-
-                while (reader.Position < reader.Length)
-                {
-                    read = reader.Read(buffer, 0, buffer.Length);
-                    writer.Write(buffer, 0, read);
-                }
+                continue;
             }
-            writer.Close();
-        }
-        finally
-        {
-            ArrayPool<byte>.Shared.Return(buffer);
+            using var reader = File.OpenRead(inputFile);
+            if (IsUtf8Bom(reader))
+            {
+                reader.Seek(0, SeekOrigin.Begin);
+            }
+            reader.CopyTo(writer);
         }
+        writer.Close();
 
         Console.WriteLine($"Bundler Completed .... {option.OutputFileName}");
     }
+
+    private static bool IsUtf8Bom(Stream stream)
+    {
+        Span<byte> buffer = stackalloc byte[3];
+        if (stream.Read(buffer) != buffer.Length)
+        {
+            return false;
+        }
+        return buffer.SequenceEqual(Encoding.UTF8.GetPreamble());
+    }
 }