From a8a7592dcac510891d3095ba61974072c2902e3d Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:29:32 -0800
Subject: [PATCH 01/16] Simplify string.Join calls

---
 MetadataExtractor/DirectoryExtensions.cs                      | 2 +-
 MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs          | 2 +-
 .../Formats/Exif/makernotes/OlympusMakernoteDescriptor.cs     | 4 ++--
 .../Exif/makernotes/OlympusRawInfoMakernoteDescriptor.cs      | 4 ++--
 .../Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs   | 2 +-
 MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs | 2 +-
 MetadataExtractor/Formats/Heif/HeifMetadataReader.cs          | 2 +-
 MetadataExtractor/Formats/Icc/IccReader.cs                    | 2 +-
 MetadataExtractor/Formats/Iptc/IptcReader.cs                  | 2 +-
 MetadataExtractor/Formats/Iptc/Iso2022Converter.cs            | 2 +-
 MetadataExtractor/Formats/Png/PngChunkType.cs                 | 2 +-
 MetadataExtractor/Formats/Png/PngDescriptor.cs                | 4 +---
 .../Formats/QuickTime/QuickTimeMetadataReader.cs              | 2 +-
 MetadataExtractor/Formats/QuickTime/QuickTimeReader.cs        | 2 +-
 MetadataExtractor/IO/IndexedReader.cs                         | 2 +-
 MetadataExtractor/IO/SequentialReader.cs                      | 2 +-
 MetadataExtractor/TagDescriptor.cs                            | 3 +--
 17 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/MetadataExtractor/DirectoryExtensions.cs b/MetadataExtractor/DirectoryExtensions.cs
index f5be0149d..9c2a4851a 100644
--- a/MetadataExtractor/DirectoryExtensions.cs
+++ b/MetadataExtractor/DirectoryExtensions.cs
@@ -929,7 +929,7 @@ public static bool TryGetRational(this Directory directory, int tagType, out Rat
         {
             var bytes = directory.GetByteArray(tagType);
             return bytes is null ? null
-                : encoding.GetString(bytes, 0, bytes.Length);
+                : encoding.GetString(bytes);
         }
 
         public static StringValue GetStringValue(this Directory directory, int tagType)
diff --git a/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs b/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs
index e35da0c27..64650f58c 100644
--- a/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs
+++ b/MetadataExtractor/Formats/Exif/ExifDescriptorBase.cs
@@ -173,7 +173,7 @@ public abstract class ExifDescriptorBase<T>(T directory)
             try
             {
                 // Decode the Unicode string and trim the Unicode zero "\0" from the end.
-                return Encoding.Unicode.GetString(bytes, 0, bytes.Length).TrimEnd('\0');
+                return Encoding.Unicode.GetString(bytes).TrimEnd('\0');
             }
             catch
             {
diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusMakernoteDescriptor.cs
index 49ca342c1..3c3f5b7f6 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusMakernoteDescriptor.cs
@@ -471,7 +471,7 @@ public sealed class OlympusMakernoteDescriptor(OlympusMakernoteDirectory directo
             if (Directory.GetObject(OlympusMakernoteDirectory.TagColourMatrix) is not short[] values)
                 return null;
 
-            return string.Join(" ", values.Select(b => b.ToString()).ToArray());
+            return string.Join(" ", values);
         }
 
         public string? GetWbModeDescription()
@@ -574,7 +574,7 @@ public sealed class OlympusMakernoteDescriptor(OlympusMakernoteDirectory directo
             if (bytes is null)
                 return null;
 
-            return Encoding.UTF8.GetString(bytes, 0, bytes.Length);
+            return Encoding.UTF8.GetString(bytes);
         }
 
         public string? GetOneTouchWbDescription()
diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusRawInfoMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusRawInfoMakernoteDescriptor.cs
index 2537f6c05..5d4cbe8e2 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusRawInfoMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusRawInfoMakernoteDescriptor.cs
@@ -32,7 +32,7 @@ public sealed class OlympusRawInfoMakernoteDescriptor(OlympusRawInfoMakernoteDir
             if (Directory.GetObject(OlympusRawInfoMakernoteDirectory.TagColorMatrix2) is not short[] values)
                 return null;
 
-            return string.Join(" ", values.Select(b => b.ToString()).ToArray());
+            return string.Join(" ", values);
         }
 
         public string? GetYCbCrCoefficientsDescription()
@@ -46,7 +46,7 @@ public sealed class OlympusRawInfoMakernoteDescriptor(OlympusRawInfoMakernoteDir
                 ret[i] = new Rational(values[2 * i], values[2 * i + 1]);
             }
 
-            return string.Join(" ", ret.Select(r => r.ToDecimal().ToString()).ToArray());
+            return string.Join(" ", ret.Select(r => r.ToDecimal()));
         }
 
         public string? GetOlympusLightSourceDescription()
diff --git a/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs
index c3af31649..5bfe18c24 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/PanasonicMakernoteDescriptor.cs
@@ -255,7 +255,7 @@ public sealed class PanasonicMakernoteDescriptor(PanasonicMakernoteDirectory dir
             if (bytes is null)
                 return null;
 
-            return string.Join(".", bytes.Select(b => b.ToString()).ToArray());
+            return string.Join(".", bytes);
         }
 
         public string? GetIntelligentDRangeDescription()
diff --git a/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs b/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
index 1721a3880..6e41763bc 100644
--- a/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
+++ b/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
@@ -15,7 +15,7 @@ public class HeicImagePropertyDescriptor(HeicImagePropertiesDirectory directory)
                     return Directory.GetString(tagType) + " degrees";
                 case HeicImagePropertiesDirectory.TagPixelDepths:
                     var o = Directory.GetObject(HeicImagePropertiesDirectory.TagPixelDepths);
-                    return o is null ? null : string.Join(" ", ((byte[])o).Select(i => i.ToString()).ToArray());
+                    return o is null ? null : string.Join(" ", ((byte[])o).Select(i => i.ToString()));
                 case HeicImagePropertiesDirectory.TagColorFormat:
                     return TypeStringConverter.ToTypeString(Directory.GetUInt32(HeicImagePropertiesDirectory.TagColorFormat));
                 case HeicImagePropertiesDirectory.TagColorPrimaries:
diff --git a/MetadataExtractor/Formats/Heif/HeifMetadataReader.cs b/MetadataExtractor/Formats/Heif/HeifMetadataReader.cs
index 8a79feb9f..098bbb68c 100644
--- a/MetadataExtractor/Formats/Heif/HeifMetadataReader.cs
+++ b/MetadataExtractor/Formats/Heif/HeifMetadataReader.cs
@@ -66,7 +66,7 @@ void ParseQuickTimeTest()
                     {
                         dir.Set(
                             QuickTimeFileTypeDirectory.TagCompatibleBrands,
-                            string.Join(", ", ftype.CompatibleBrandStrings.ToArray()));
+                            string.Join(", ", ftype.CompatibleBrandStrings));
                     }
 
                     directories.Add(dir);
diff --git a/MetadataExtractor/Formats/Icc/IccReader.cs b/MetadataExtractor/Formats/Icc/IccReader.cs
index 58c3a0fd3..5632a326e 100644
--- a/MetadataExtractor/Formats/Icc/IccReader.cs
+++ b/MetadataExtractor/Formats/Icc/IccReader.cs
@@ -162,7 +162,7 @@ public static string GetStringFromUInt32(uint d)
                 unchecked((byte)d)
             };
 
-            return Encoding.UTF8.GetString(b, 0, b.Length);
+            return Encoding.UTF8.GetString(b);
         }
     }
 }
diff --git a/MetadataExtractor/Formats/Iptc/IptcReader.cs b/MetadataExtractor/Formats/Iptc/IptcReader.cs
index fb2872cdb..af85e6a0e 100644
--- a/MetadataExtractor/Formats/Iptc/IptcReader.cs
+++ b/MetadataExtractor/Formats/Iptc/IptcReader.cs
@@ -150,7 +150,7 @@ private static void ProcessTag(SequentialReader reader, Directory directory, int
                     if (charset is null)
                     {
                         // Unable to determine the charset, so fall through and treat tag as a regular string
-                        charset = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
+                        charset = Encoding.UTF8.GetString(bytes);
                     }
                     directory.Set(tagIdentifier, charset);
                     return;
diff --git a/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs b/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
index 0f3bcfaa0..33f12ecce 100644
--- a/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
+++ b/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
@@ -91,7 +91,7 @@ public static class Iso2022Converter
             {
                 try
                 {
-                    var s = encoding.GetString(bytes, 0, bytes.Length);
+                    var s = encoding.GetString(bytes);
                     if (s.IndexOf((char)65533) != -1)
                         continue;
                     return encoding;
diff --git a/MetadataExtractor/Formats/Png/PngChunkType.cs b/MetadataExtractor/Formats/Png/PngChunkType.cs
index 6b159c26f..3e423b697 100644
--- a/MetadataExtractor/Formats/Png/PngChunkType.cs
+++ b/MetadataExtractor/Formats/Png/PngChunkType.cs
@@ -146,7 +146,7 @@ private static void ValidateBytes(byte[] bytes)
 
         private static bool IsValidByte(byte b) => b is >= 65 and <= 90 or >= 97 and <= 122;
 
-        public string Identifier => Encoding.UTF8.GetString(_bytes, 0, _bytes.Length);
+        public string Identifier => Encoding.UTF8.GetString(_bytes);
 
         public override string ToString() => Identifier;
 
diff --git a/MetadataExtractor/Formats/Png/PngDescriptor.cs b/MetadataExtractor/Formats/Png/PngDescriptor.cs
index e1118878d..1f019323e 100644
--- a/MetadataExtractor/Formats/Png/PngDescriptor.cs
+++ b/MetadataExtractor/Formats/Png/PngDescriptor.cs
@@ -73,9 +73,7 @@ public sealed class PngDescriptor(PngDirectory directory)
         {
             return Directory.GetObject(PngDirectory.TagTextualData) is not IList<KeyValuePair> pairs
                 ? null
-                : string.Join(
-                    "\n",
-                    pairs.Select(kv => $"{kv.Key}: {kv.Value}"));
+                : string.Join("\n", pairs.Select(kv => $"{kv.Key}: {kv.Value}"));
         }
 
         public string? GetBackgroundColorDescription()
diff --git a/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs b/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
index 150213fa5..dabce333c 100644
--- a/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
+++ b/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
@@ -296,7 +296,7 @@ void MoovHandler(AtomCallbackArgs a)
                         a.Reader.Skip(4L);
                         var partId = a.Reader.GetUInt32();
                         var featureCode = a.Reader.GetUInt32();
-                        var featureValue = string.Join(" ", a.Reader.GetBytes(4).Select(v => v.ToString("X2")).ToArray());
+                        var featureValue = string.Join(" ", a.Reader.GetBytes(4).Select(v => v.ToString("X2")));
                         Debug.WriteLine($"PartId={partId} FeatureCode={featureCode} FeatureValue={featureValue}");
                         break;
                     }
diff --git a/MetadataExtractor/Formats/QuickTime/QuickTimeReader.cs b/MetadataExtractor/Formats/QuickTime/QuickTimeReader.cs
index cd8aa92f5..07eb7a055 100644
--- a/MetadataExtractor/Formats/QuickTime/QuickTimeReader.cs
+++ b/MetadataExtractor/Formats/QuickTime/QuickTimeReader.cs
@@ -50,7 +50,7 @@ public string TypeString
                 var bytes = BitConverter.GetBytes(Type);
                 Array.Reverse(bytes);
 #if NETSTANDARD1_3
-                return Encoding.UTF8.GetString(bytes, 0, bytes.Length);
+                return Encoding.UTF8.GetString(bytes);
 #else
                 return Encoding.ASCII.GetString(bytes);
 #endif
diff --git a/MetadataExtractor/IO/IndexedReader.cs b/MetadataExtractor/IO/IndexedReader.cs
index 16a9b2237..36cf5d962 100644
--- a/MetadataExtractor/IO/IndexedReader.cs
+++ b/MetadataExtractor/IO/IndexedReader.cs
@@ -346,7 +346,7 @@ public string GetNullTerminatedString(int index, int maxLengthBytes, Encoding? e
         {
             var bytes = GetNullTerminatedBytes(index, maxLengthBytes);
 
-            return (encoding ?? Encoding.UTF8).GetString(bytes, 0, bytes.Length);
+            return (encoding ?? Encoding.UTF8).GetString(bytes);
         }
 
         /// <summary>
diff --git a/MetadataExtractor/IO/SequentialReader.cs b/MetadataExtractor/IO/SequentialReader.cs
index 97f82b746..69e6557ed 100644
--- a/MetadataExtractor/IO/SequentialReader.cs
+++ b/MetadataExtractor/IO/SequentialReader.cs
@@ -255,7 +255,7 @@ public string GetNullTerminatedString(int maxLengthBytes, Encoding? encoding = n
         {
             var bytes = GetNullTerminatedBytes(maxLengthBytes, moveToMaxLength);
 
-            return (encoding ?? Encoding.UTF8).GetString(bytes, 0, bytes.Length);
+            return (encoding ?? Encoding.UTF8).GetString(bytes);
         }
 
         /// <summary>
diff --git a/MetadataExtractor/TagDescriptor.cs b/MetadataExtractor/TagDescriptor.cs
index 48ba39ac6..1bd7ac57c 100644
--- a/MetadataExtractor/TagDescriptor.cs
+++ b/MetadataExtractor/TagDescriptor.cs
@@ -221,8 +221,7 @@ public TagDescriptor(T directory)
 
             try
             {
-                return Encoding.UTF8
-                    .GetString(values, 0, values.Length)
+                return Encoding.UTF8.GetString(values)
                     .Trim('\0', ' ', '\r', '\n', '\t');
             }
             catch

From 99e3faebeaf2c821fe725dbe078d3caf3d01bcf5 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:29:44 -0800
Subject: [PATCH 02/16] Fix formatting

---
 .../Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs      | 2 +-
 MetadataExtractor/Formats/Iso14496/TypeStringConverter.cs       | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
index 582e4ba82..2fbd46e29 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
@@ -109,7 +109,7 @@ public sealed class OlympusFocusInfoMakernoteDescriptor(OlympusFocusInfoMakernot
             if (values.Length == 0)
                 return null;
 
-            var join = $"{values[0]}" + (values.Length > 1 ? $"{ values[1]}" : "");
+            var join = $"{values[0]}" + (values.Length > 1 ? $"{values[1]}" : "");
 
             return join switch
             {
diff --git a/MetadataExtractor/Formats/Iso14496/TypeStringConverter.cs b/MetadataExtractor/Formats/Iso14496/TypeStringConverter.cs
index cefae5e48..8bdd417ca 100644
--- a/MetadataExtractor/Formats/Iso14496/TypeStringConverter.cs
+++ b/MetadataExtractor/Formats/Iso14496/TypeStringConverter.cs
@@ -26,7 +26,7 @@ public static uint ToTypeId(string typeString)
                 (((typeString[0] & 0xFF) << 24) |
                  ((typeString[1] & 0xFF) << 16) |
                  ((typeString[2] & 0xFF) << 8) |
-                 ( typeString[3] & 0xFF));
+                 (typeString[3] & 0xFF));
         }
     }
 }

From 03a8a061c7a45d75d856815820fb5a8d96c69ee5 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:29:56 -0800
Subject: [PATCH 03/16] Use new GetString polyfill

---
 MetadataExtractor/Formats/Riff/RiffReader.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/Riff/RiffReader.cs b/MetadataExtractor/Formats/Riff/RiffReader.cs
index 5ddedfb5a..fe7406dd1 100644
--- a/MetadataExtractor/Formats/Riff/RiffReader.cs
+++ b/MetadataExtractor/Formats/Riff/RiffReader.cs
@@ -31,7 +31,7 @@ public void ProcessRiff(SequentialReader reader, IRiffHandler handler)
                 Span<byte> fileFourCc = stackalloc byte[4];
                 reader.GetBytes(fileFourCc);
                 if (!fileFourCc.SequenceEqual("RIFF"u8))
-                    throw new RiffProcessingException("Invalid RIFF header: " + Encoding.ASCII.GetString(fileFourCc.ToArray()));
+                    throw new RiffProcessingException("Invalid RIFF header: " + Encoding.ASCII.GetString(fileFourCc));
 
                 // The total size of the chunks that follow plus 4 bytes for the 'WEBP' or 'AVI ' FourCC
                 int fileSize = reader.GetInt32();

From 731ada762392d63d2568580e444df85e36cb625e Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:31:17 -0800
Subject: [PATCH 04/16] Remove Empty class

---
 MetadataExtractor/Formats/Wav/WavFormatDescriptor.cs | 2 +-
 MetadataExtractor/IO/IndexedReader.cs                | 2 +-
 MetadataExtractor/IO/SequentialReader.cs             | 2 +-
 MetadataExtractor/Util/Empty.cs                      | 8 --------
 4 files changed, 3 insertions(+), 11 deletions(-)
 delete mode 100644 MetadataExtractor/Util/Empty.cs

diff --git a/MetadataExtractor/Formats/Wav/WavFormatDescriptor.cs b/MetadataExtractor/Formats/Wav/WavFormatDescriptor.cs
index 04dd98871..0eb11f12d 100644
--- a/MetadataExtractor/Formats/Wav/WavFormatDescriptor.cs
+++ b/MetadataExtractor/Formats/Wav/WavFormatDescriptor.cs
@@ -14,7 +14,7 @@ public sealed class WavFormatDescriptor(WavFormatDirectory directory) : TagDescr
                 TagFormat => GetFormatDescription(),
                 TagSamplesPerSec => Directory.GetUInt32(tag).ToString("0 bps"),
                 TagBytesPerSec => Directory.GetUInt32(tag).ToString("0 bps"),
-                TagSubformat => BitConverter.ToString(Directory.GetByteArray(tag) ?? Empty.ByteArray).Replace("-", ""),
+                TagSubformat => BitConverter.ToString(Directory.GetByteArray(tag) ?? []).Replace("-", ""),
                 _ => base.GetDescription(tag),
             };
         }
diff --git a/MetadataExtractor/IO/IndexedReader.cs b/MetadataExtractor/IO/IndexedReader.cs
index 36cf5d962..1ad977d2f 100644
--- a/MetadataExtractor/IO/IndexedReader.cs
+++ b/MetadataExtractor/IO/IndexedReader.cs
@@ -388,7 +388,7 @@ public byte[] GetNullTerminatedBytes(int index, int maxLengthBytes)
                 length++;
 
             if (length == 0)
-                return Empty.ByteArray;
+                return [];
             if (length == maxLengthBytes)
                 return buffer;
 
diff --git a/MetadataExtractor/IO/SequentialReader.cs b/MetadataExtractor/IO/SequentialReader.cs
index 69e6557ed..d16888206 100644
--- a/MetadataExtractor/IO/SequentialReader.cs
+++ b/MetadataExtractor/IO/SequentialReader.cs
@@ -320,7 +320,7 @@ public byte[] GetNullTerminatedBytes(int maxLengthBytes, bool moveToMaxLength =
             }
 
             if (length == 0)
-                return Empty.ByteArray;
+                return [];
             if (length == maxLengthBytes)
                 return buffer;
             var bytes = new byte[length];
diff --git a/MetadataExtractor/Util/Empty.cs b/MetadataExtractor/Util/Empty.cs
deleted file mode 100644
index 2a19eade9..000000000
--- a/MetadataExtractor/Util/Empty.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
-
-namespace MetadataExtractor;
-
-internal static class Empty
-{
-    public static readonly byte[] ByteArray = [];
-}

From ad1e954218378d0bc19e4b5457024c9b64bb9af4 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:35:36 -0800
Subject: [PATCH 05/16] Eliminate byte[] allocation in QuickTimeMetadataReader

---
 .../Formats/QuickTime/QuickTimeMetadataReader.cs              | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs b/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
index dabce333c..c3a295c69 100644
--- a/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
+++ b/MetadataExtractor/Formats/QuickTime/QuickTimeMetadataReader.cs
@@ -318,7 +318,9 @@ void Handler(AtomCallbackArgs a)
                         ReadOnlySpan<byte> xmp = [0xbe, 0x7a, 0xcf, 0xcb, 0x97, 0xa9, 0x42, 0xe8, 0x9c, 0x71, 0x99, 0x94, 0x91, 0xe3, 0xaf, 0xac];
                         if (a.BytesLeft >= xmp.Length)
                         {
-                            var uuid = a.Reader.GetBytes(xmp.Length);
+                            Span<byte> uuid = stackalloc byte[16]; // xmp length is 16
+
+                            a.Reader.GetBytes(uuid);
                             if (xmp.SequenceEqual(uuid))
                             {
                                 var xmpBytes = a.Reader.GetNullTerminatedBytes((int)a.BytesLeft);

From 3fcef87edbe992cc5feee489584ddd9460550f60 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:40:53 -0800
Subject: [PATCH 06/16] Eliminate allocation in Get4ccString

---
 .../Formats/QuickTime/QuickTimeReaderExtensions.cs    | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs b/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
index 76eeb98ca..17f3be52e 100644
--- a/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
+++ b/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
@@ -9,12 +9,11 @@ public static class QuickTimeReaderExtensions
     {
         public static string Get4ccString(this SequentialReader reader)
         {
-            var sb = new StringBuilder(4);
-            sb.Append((char)reader.GetByte());
-            sb.Append((char)reader.GetByte());
-            sb.Append((char)reader.GetByte());
-            sb.Append((char)reader.GetByte());
-            return sb.ToString();
+            Span<byte> bytes = stackalloc byte[4];
+
+            reader.GetBytes(bytes);
+
+            return new string([(char)bytes[0], (char)bytes[1], (char)bytes[2], (char)bytes[3]]);
         }
 
         public static decimal Get16BitFixedPoint(this SequentialReader reader)

From 1ddd6273021e86b0c2701445b0a0fe2af49c7254 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:48:25 -0800
Subject: [PATCH 07/16] Update ShouldAcceptList to accept utf8 bytes

---
 MetadataExtractor/Formats/Avi/AviRiffHandler.cs       | 11 +++++------
 MetadataExtractor/Formats/Riff/IRiffHandler.cs        |  2 +-
 MetadataExtractor/Formats/Riff/RiffHandler.cs         |  2 +-
 MetadataExtractor/Formats/Riff/RiffReader.cs          |  2 +-
 MetadataExtractor/Formats/Wav/WavRiffHandler.cs       |  2 +-
 MetadataExtractor/Formats/WebP/WebpRiffHandler.cs     |  2 +-
 .../PublicAPI/net462/PublicAPI.Shipped.txt            | 10 +++++-----
 .../PublicAPI/netstandard1.3/PublicAPI.Shipped.txt    | 10 +++++-----
 .../PublicAPI/netstandard2.1/PublicAPI.Shipped.txt    | 10 +++++-----
 9 files changed, 25 insertions(+), 26 deletions(-)

diff --git a/MetadataExtractor/Formats/Avi/AviRiffHandler.cs b/MetadataExtractor/Formats/Avi/AviRiffHandler.cs
index 852beb7b6..03ab69f97 100644
--- a/MetadataExtractor/Formats/Avi/AviRiffHandler.cs
+++ b/MetadataExtractor/Formats/Avi/AviRiffHandler.cs
@@ -39,13 +39,12 @@ public AviRiffHandler(List<Directory> directories)
             _ => false
         };
 
-        public bool ShouldAcceptList(string fourCc) => fourCc switch
+        public bool ShouldAcceptList(ReadOnlySpan<byte> fourCc)
         {
-            "hdrl" => true,
-            "strl" => true,
-            "AVI " => true,
-            _ => false
-        };
+            return fourCc.SequenceEqual("hdrl"u8)
+                || fourCc.SequenceEqual("strl"u8)
+                || fourCc.SequenceEqual("AVI "u8);
+        }
 
         public void ProcessChunk(string fourCc, byte[] payload)
         {
diff --git a/MetadataExtractor/Formats/Riff/IRiffHandler.cs b/MetadataExtractor/Formats/Riff/IRiffHandler.cs
index 283a2d694..711493f42 100644
--- a/MetadataExtractor/Formats/Riff/IRiffHandler.cs
+++ b/MetadataExtractor/Formats/Riff/IRiffHandler.cs
@@ -33,7 +33,7 @@ public interface IRiffHandler
         /// </remarks>
         /// <param name="fourCc">the four character code of this chunk</param>
         /// <returns><see langword="true"/> if <see cref="ProcessChunk(string, byte[])"/> should be called, otherwise <see langword="false"/>.</returns>
-        bool ShouldAcceptList(string fourCc);
+        bool ShouldAcceptList(ReadOnlySpan<byte> fourCc);
 
         /// <summary>Perform whatever processing is necessary for the type of chunk with its payload.</summary>
         /// <remarks>This is only called if a previous call to <see cref="ShouldAcceptChunk(string)"/> with the same <c>fourCC</c> returned <see langword="true"/>.</remarks>
diff --git a/MetadataExtractor/Formats/Riff/RiffHandler.cs b/MetadataExtractor/Formats/Riff/RiffHandler.cs
index 66ee2522f..e3ea3cef9 100644
--- a/MetadataExtractor/Formats/Riff/RiffHandler.cs
+++ b/MetadataExtractor/Formats/Riff/RiffHandler.cs
@@ -30,7 +30,7 @@ public void ProcessChunk(string fourCc, byte[] payload)
 
         public abstract bool ShouldAcceptRiffIdentifier(ReadOnlySpan<byte> identifier);
 
-        public abstract bool ShouldAcceptList(string fourCc);
+        public abstract bool ShouldAcceptList(ReadOnlySpan<byte> fourCc);
 
         public void AddError(string errorMessage)
         {
diff --git a/MetadataExtractor/Formats/Riff/RiffReader.cs b/MetadataExtractor/Formats/Riff/RiffReader.cs
index fe7406dd1..8e1ea022f 100644
--- a/MetadataExtractor/Formats/Riff/RiffReader.cs
+++ b/MetadataExtractor/Formats/Riff/RiffReader.cs
@@ -70,7 +70,7 @@ private static void ProcessChunks(SequentialReader reader, long maxPosition, IRi
                 {
                     if (chunkSize < 4)
                         break;
-                    string listName = reader.GetString(4, Encoding.ASCII);
+                    ReadOnlySpan<byte> listName = reader.GetBytes(4);
                     if (handler.ShouldAcceptList(listName))
                         ProcessChunks(reader, reader.Position + chunkSize - 4, handler);
                     else
diff --git a/MetadataExtractor/Formats/Wav/WavRiffHandler.cs b/MetadataExtractor/Formats/Wav/WavRiffHandler.cs
index 56b1149e1..11d1d094e 100644
--- a/MetadataExtractor/Formats/Wav/WavRiffHandler.cs
+++ b/MetadataExtractor/Formats/Wav/WavRiffHandler.cs
@@ -30,6 +30,6 @@ public WavRiffHandler(List<Directory> directories)
 
         public override bool ShouldAcceptRiffIdentifier(ReadOnlySpan<byte> identifier) => identifier.SequenceEqual("WAVE"u8);
 
-        public override bool ShouldAcceptList(string fourCc) => false;
+        public override bool ShouldAcceptList(ReadOnlySpan<byte> fourCc) => false;
     }
 }
diff --git a/MetadataExtractor/Formats/WebP/WebpRiffHandler.cs b/MetadataExtractor/Formats/WebP/WebpRiffHandler.cs
index 31bdfc277..42f259f45 100644
--- a/MetadataExtractor/Formats/WebP/WebpRiffHandler.cs
+++ b/MetadataExtractor/Formats/WebP/WebpRiffHandler.cs
@@ -39,7 +39,7 @@ public bool ShouldAcceptChunk(string fourCc) => fourCc == "VP8X" ||
                                                         fourCc == "ICCP" ||
                                                         fourCc == "XMP ";
 
-        public bool ShouldAcceptList(string fourCc) => false;
+        public bool ShouldAcceptList(ReadOnlySpan<byte> fourCc) => false;
 
         public void ProcessChunk(string fourCc, byte[] payload)
         {
diff --git a/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
index f36b2666f..8706df28b 100644
--- a/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
@@ -5,7 +5,7 @@ abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.Pr
 abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.SegmentTypes.get -> System.Collections.Generic.IReadOnlyCollection<MetadataExtractor.Formats.Jpeg.JpegSegmentType>!
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.MinSize.get -> int
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.Populate(T! directory, byte[]! payload) -> void
-abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(string! fourCc) -> bool
+abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.CustomProcessTag(in MetadataExtractor.Formats.Tiff.TiffReaderContext context, int tagId, int valueOffset, int byteCount) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.HasFollowerIfd() -> bool
@@ -2387,7 +2387,7 @@ MetadataExtractor.Formats.Avi.AviRiffHandler.AddError(string! errorMessage) -> v
 MetadataExtractor.Formats.Avi.AviRiffHandler.AviRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor.BmpHeaderDescriptor(MetadataExtractor.Formats.Bmp.BmpHeaderDirectory! directory) -> void
@@ -3699,7 +3699,7 @@ MetadataExtractor.Formats.Riff.IRiffHandler
 MetadataExtractor.Formats.Riff.IRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.ProcessChunk(string! fourCc, byte[]! payload) -> void
@@ -3864,7 +3864,7 @@ MetadataExtractor.Formats.WebP.WebPRiffHandler
 MetadataExtractor.Formats.WebP.WebPRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.WebPRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Xmp.Schema
@@ -4248,7 +4248,7 @@ override MetadataExtractor.Formats.Tiff.TiffDataFormat.ToString() -> string!
 override MetadataExtractor.Formats.Wav.WavFactDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Wav.WavFormatDescriptor.GetDescription(int tag) -> string?
 override MetadataExtractor.Formats.Wav.WavFormatDirectory.Name.get -> string!
-override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 override MetadataExtractor.Formats.WebP.WebPDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Xmp.XmpDirectory.Name.get -> string!
diff --git a/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
index 8d36dd9e4..b4590108a 100644
--- a/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
@@ -5,7 +5,7 @@ abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.Pr
 abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.SegmentTypes.get -> System.Collections.Generic.IReadOnlyCollection<MetadataExtractor.Formats.Jpeg.JpegSegmentType>!
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.MinSize.get -> int
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.Populate(T! directory, byte[]! payload) -> void
-abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(string! fourCc) -> bool
+abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.CustomProcessTag(in MetadataExtractor.Formats.Tiff.TiffReaderContext context, int tagId, int valueOffset, int byteCount) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.HasFollowerIfd() -> bool
@@ -2387,7 +2387,7 @@ MetadataExtractor.Formats.Avi.AviRiffHandler.AddError(string! errorMessage) -> v
 MetadataExtractor.Formats.Avi.AviRiffHandler.AviRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor.BmpHeaderDescriptor(MetadataExtractor.Formats.Bmp.BmpHeaderDirectory! directory) -> void
@@ -3697,7 +3697,7 @@ MetadataExtractor.Formats.Riff.IRiffHandler
 MetadataExtractor.Formats.Riff.IRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.ProcessChunk(string! fourCc, byte[]! payload) -> void
@@ -3860,7 +3860,7 @@ MetadataExtractor.Formats.WebP.WebPRiffHandler
 MetadataExtractor.Formats.WebP.WebPRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.WebPRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Xmp.Schema
@@ -4241,7 +4241,7 @@ override MetadataExtractor.Formats.Tiff.TiffDataFormat.ToString() -> string!
 override MetadataExtractor.Formats.Wav.WavFactDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Wav.WavFormatDescriptor.GetDescription(int tag) -> string?
 override MetadataExtractor.Formats.Wav.WavFormatDirectory.Name.get -> string!
-override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 override MetadataExtractor.Formats.WebP.WebPDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Xmp.XmpDirectory.Name.get -> string!
diff --git a/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
index 7bd81fc0d..e525cde9c 100644
--- a/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
@@ -5,7 +5,7 @@ abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.Pr
 abstract MetadataExtractor.Formats.Jpeg.JpegSegmentWithPreambleMetadataReader.SegmentTypes.get -> System.Collections.Generic.IReadOnlyCollection<MetadataExtractor.Formats.Jpeg.JpegSegmentType>!
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.MinSize.get -> int
 abstract MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.Populate(T! directory, byte[]! payload) -> void
-abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(string! fourCc) -> bool
+abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 abstract MetadataExtractor.Formats.Riff.RiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.CustomProcessTag(in MetadataExtractor.Formats.Tiff.TiffReaderContext context, int tagId, int valueOffset, int byteCount) -> bool
 abstract MetadataExtractor.Formats.Tiff.DirectoryTiffHandler.HasFollowerIfd() -> bool
@@ -2382,7 +2382,7 @@ MetadataExtractor.Formats.Avi.AviRiffHandler.AddError(string! errorMessage) -> v
 MetadataExtractor.Formats.Avi.AviRiffHandler.AviRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Avi.AviRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor
 MetadataExtractor.Formats.Bmp.BmpHeaderDescriptor.BmpHeaderDescriptor(MetadataExtractor.Formats.Bmp.BmpHeaderDirectory! directory) -> void
@@ -3694,7 +3694,7 @@ MetadataExtractor.Formats.Riff.IRiffHandler
 MetadataExtractor.Formats.Riff.IRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.Riff.IRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>
 MetadataExtractor.Formats.Riff.RiffChunkHandler<T>.ProcessChunk(string! fourCc, byte[]! payload) -> void
@@ -3859,7 +3859,7 @@ MetadataExtractor.Formats.WebP.WebPRiffHandler
 MetadataExtractor.Formats.WebP.WebPRiffHandler.AddError(string! errorMessage) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ProcessChunk(string! fourCc, byte[]! payload) -> void
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptChunk(string! fourCc) -> bool
-MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 MetadataExtractor.Formats.WebP.WebPRiffHandler.WebPRiffHandler(System.Collections.Generic.List<MetadataExtractor.Directory!>! directories) -> void
 MetadataExtractor.Formats.Xmp.Schema
@@ -4243,7 +4243,7 @@ override MetadataExtractor.Formats.Tiff.TiffDataFormat.ToString() -> string!
 override MetadataExtractor.Formats.Wav.WavFactDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Wav.WavFormatDescriptor.GetDescription(int tag) -> string?
 override MetadataExtractor.Formats.Wav.WavFormatDirectory.Name.get -> string!
-override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(string! fourCc) -> bool
+override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptList(System.ReadOnlySpan<byte> fourCc) -> bool
 override MetadataExtractor.Formats.Wav.WavRiffHandler.ShouldAcceptRiffIdentifier(System.ReadOnlySpan<byte> identifier) -> bool
 override MetadataExtractor.Formats.WebP.WebPDirectory.Name.get -> string!
 override MetadataExtractor.Formats.Xmp.XmpDirectory.Name.get -> string!

From 0443c5487dc23924523c7eb8f2bd611d0deed276 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 09:59:11 -0800
Subject: [PATCH 08/16] Update StartsWithJpegExifPreamble to accept
 ReadOnlySpan<byte>

---
 MetadataExtractor/Formats/Exif/ExifReader.cs                    | 2 +-
 MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt        | 2 +-
 .../PublicAPI/netstandard1.3/PublicAPI.Shipped.txt              | 2 +-
 .../PublicAPI/netstandard2.1/PublicAPI.Shipped.txt              | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/MetadataExtractor/Formats/Exif/ExifReader.cs b/MetadataExtractor/Formats/Exif/ExifReader.cs
index 2eec871c2..027e596be 100644
--- a/MetadataExtractor/Formats/Exif/ExifReader.cs
+++ b/MetadataExtractor/Formats/Exif/ExifReader.cs
@@ -15,7 +15,7 @@ public sealed class ExifReader : JpegSegmentWithPreambleMetadataReader
     {
         public static ReadOnlySpan<byte> JpegSegmentPreamble => "Exif\x0\x0"u8;
 
-        public static bool StartsWithJpegExifPreamble(byte[] bytes) => bytes.AsSpan().StartsWith(JpegSegmentPreamble);
+        public static bool StartsWithJpegExifPreamble(ReadOnlySpan<byte> bytes) => bytes.StartsWith(JpegSegmentPreamble);
 
         public static int JpegSegmentPreambleLength => JpegSegmentPreamble.Length;
 
diff --git a/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
index 8706df28b..1cbba6c7b 100644
--- a/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/net462/PublicAPI.Shipped.txt
@@ -4333,7 +4333,7 @@ static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(string! file
 static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Exif.ExifDirectoryBase.AddExifTagNames(System.Collections.Generic.Dictionary<int, string!>! map) -> void
 static MetadataExtractor.Formats.Exif.ExifReader.JpegSegmentPreambleLength.get -> int
-static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(byte[]! bytes) -> bool
+static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(System.ReadOnlySpan<byte> bytes) -> bool
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(string! filePath) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Heif.HeifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
diff --git a/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
index b4590108a..9ef730822 100644
--- a/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Shipped.txt
@@ -4326,7 +4326,7 @@ static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(string! file
 static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Exif.ExifDirectoryBase.AddExifTagNames(System.Collections.Generic.Dictionary<int, string!>! map) -> void
 static MetadataExtractor.Formats.Exif.ExifReader.JpegSegmentPreambleLength.get -> int
-static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(byte[]! bytes) -> bool
+static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(System.ReadOnlySpan<byte> bytes) -> bool
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(string! filePath) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Heif.HeifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
diff --git a/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt b/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
index e525cde9c..9c2816869 100644
--- a/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
+++ b/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Shipped.txt
@@ -4328,7 +4328,7 @@ static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(string! file
 static MetadataExtractor.Formats.Eps.EpsMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Exif.ExifDirectoryBase.AddExifTagNames(System.Collections.Generic.Dictionary<int, string!>! map) -> void
 static MetadataExtractor.Formats.Exif.ExifReader.JpegSegmentPreambleLength.get -> int
-static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(byte[]! bytes) -> bool
+static MetadataExtractor.Formats.Exif.ExifReader.StartsWithJpegExifPreamble(System.ReadOnlySpan<byte> bytes) -> bool
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(string! filePath) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Gif.GifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!
 static MetadataExtractor.Formats.Heif.HeifMetadataReader.ReadMetadata(System.IO.Stream! stream) -> System.Collections.Generic.IReadOnlyList<MetadataExtractor.Directory!>!

From 7c5a6ca09d95f4d024e09478b7a28ff2c4d04a37 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 10:14:44 -0800
Subject: [PATCH 09/16] Use switch expression

---
 MetadataExtractor/Formats/Gif/GifReader.cs | 35 +++++-----------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/MetadataExtractor/Formats/Gif/GifReader.cs b/MetadataExtractor/Formats/Gif/GifReader.cs
index 4a880212a..3b354afad 100644
--- a/MetadataExtractor/Formats/Gif/GifReader.cs
+++ b/MetadataExtractor/Formats/Gif/GifReader.cs
@@ -190,35 +190,14 @@ private static GifHeaderDirectory ReadGifHeader(SequentialReader reader)
             var blockSizeBytes = reader.GetByte();
             var blockStartPos = reader.Position;
 
-            Directory? directory;
-            switch (extensionLabel)
+            Directory? directory = extensionLabel switch
             {
-                case 0x01:
-                {
-                    directory = ReadPlainTextBlock(reader, blockSizeBytes);
-                    break;
-                }
-                case 0xf9:
-                {
-                    directory = ReadControlBlock(reader);
-                    break;
-                }
-                case 0xfe:
-                {
-                    directory = ReadCommentBlock(reader, blockSizeBytes);
-                    break;
-                }
-                case 0xff:
-                {
-                    directory = ReadApplicationExtensionBlock(reader, blockSizeBytes);
-                    break;
-                }
-                default:
-                {
-                    directory = new ErrorDirectory($"Unsupported GIF extension block with type 0x{extensionLabel:X2}.");
-                    break;
-                }
-            }
+                0x01 => ReadPlainTextBlock(reader, blockSizeBytes),
+                0xf9 => ReadControlBlock(reader),
+                0xfe => ReadCommentBlock(reader, blockSizeBytes),
+                0xff => ReadApplicationExtensionBlock(reader, blockSizeBytes),
+                _ => new ErrorDirectory($"Unsupported GIF extension block with type 0x{extensionLabel:X2}.")
+            };
 
             var skipCount = blockStartPos + blockSizeBytes - reader.Position;
             if (skipCount > 0)

From b229f63e94a4f93b98ecb97b0749822bb4564b2f Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 10:34:29 -0800
Subject: [PATCH 10/16] Switch on integer values to avoid string allocation

---
 .../LeicaType5MakernoteDescriptor.cs          | 15 +++----
 ...lympusCameraSettingsMakernoteDescriptor.cs | 14 +++---
 .../OlympusFocusInfoMakernoteDescriptor.cs    | 10 ++---
 ...ympusImageProcessingMakernoteDescriptor.cs | 43 +++++++++----------
 4 files changed, 38 insertions(+), 44 deletions(-)

diff --git a/MetadataExtractor/Formats/Exif/makernotes/LeicaType5MakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/LeicaType5MakernoteDescriptor.cs
index dea35dda5..06ce84129 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/LeicaType5MakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/LeicaType5MakernoteDescriptor.cs
@@ -30,15 +30,14 @@ public class LeicaType5MakernoteDescriptor(LeicaType5MakernoteDirectory director
             if (Directory.GetObject(LeicaType5MakernoteDirectory.TagExposureMode) is not byte[] values || values.Length < 4)
                 return null;
 
-            var join = $"{values[0]} {values[1]} {values[2]} {values[3]}";
-            var ret = join switch
+            var ret = (values[0], values[1], values[2], values[3]) switch
             {
-                "0 0 0 0" => "Program AE",
-                "1 0 0 0" => "Aperture-priority AE",
-                "1 1 0 0" => "Aperture-priority AE (1)",
-                "2 0 0 0" => "Shutter speed priority AE",  // guess
-                "3 0 0 0" => "Manual",
-                _ => "Unknown (" + join + ")",
+                (0, 0, 0, 0) => "Program AE",
+                (1, 0, 0, 0) => "Aperture-priority AE",
+                (1, 1, 0, 0) => "Aperture-priority AE (1)",
+                (2, 0, 0, 0) => "Shutter speed priority AE",  // guess
+                (3, 0, 0, 0) => "Manual",
+                _ => $"Unknown ({values[0]} {values[1]} {values[2]} {values[3]})"
             };
             return ret;
         }
diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusCameraSettingsMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusCameraSettingsMakernoteDescriptor.cs
index 472da61ae..e61711690 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusCameraSettingsMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusCameraSettingsMakernoteDescriptor.cs
@@ -651,15 +651,15 @@ public sealed class OlympusCameraSettingsMakernoteDescriptor(OlympusCameraSettin
             if (Directory.GetObject(OlympusCameraSettingsMakernoteDirectory.TagGradation) is not short[] values || values.Length < 3)
                 return null;
 
-            var join = $"{values[0]} {values[1]} {values[2]}";
-            var ret = join switch
+            var ret = (values[0], values[1], values[3]) switch
             {
-                "0 0 0" => "n/a",
-                "-1 -1 1" => "Low Key",
-                "0 -1 1" => "Normal",
-                "1 -1 1" => "High Key",
-                _ => "Unknown (" + join + ")",
+                (0, 0, 0) => "n/a",
+                (-1, -1, 1) => "Low Key",
+                (0, -1, 1) => "Normal",
+                (1, -1, 1) => "High Key",
+                _ => $"Unknown ({values[0]} {values[1]} {values[2]})"
             };
+
             if (values.Length > 3)
             {
                 if (values[3] == 0)
diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
index 2fbd46e29..467e2e141 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
@@ -77,13 +77,11 @@ public sealed class OlympusFocusInfoMakernoteDescriptor(OlympusFocusInfoMakernot
             if (Directory.GetObject(OlympusFocusInfoMakernoteDirectory.TagExternalFlash) is not ushort[] values || values.Length < 2)
                 return null;
 
-            var join = $"{values[0]} {values[1]}";
-
-            return join switch
+            return (values[0], values[1]) switch
             {
-                "0 0" => "Off",
-                "1 0" => "On",
-                _ => "Unknown (" + join + ")",
+                (0, 0) => "Off",
+                (1, 0) => "On",
+                _ => $"Unknown ({values[0]} {values[1]})"
             };
         }
 
diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusImageProcessingMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusImageProcessingMakernoteDescriptor.cs
index 222eca555..514ee7f1e 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusImageProcessingMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusImageProcessingMakernoteDescriptor.cs
@@ -130,24 +130,23 @@ public sealed class OlympusImageProcessingMakernoteDescriptor(OlympusImageProces
             if (Directory.GetObject(OlympusImageProcessingMakernoteDirectory.TagAspectRatio) is not byte[] values || values.Length < 2)
                 return null;
 
-            var join = $"{values[0]} {values[1]}";
-            var ret = join switch
+            var ret = (values[0], values[1]) switch
             {
-                "1 1" => "4:3",
-                "1 4" => "1:1",
-                "2 1" => "3:2 (RAW)",
-                "2 2" => "3:2",
-                "3 1" => "16:9 (RAW)",
-                "3 3" => "16:9",
-                "4 1" => "1:1 (RAW)",
-                "4 4" => "6:6",
-                "5 5" => "5:4",
-                "6 6" => "7:6",
-                "7 7" => "6:5",
-                "8 8" => "7:5",
-                "9 1" => "3:4 (RAW)",
-                "9 9" => "3:4",
-                _ => "Unknown (" + join + ")",
+                (1, 1) => "4:3",
+                (1, 4) => "1:1",
+                (2, 1) => "3:2 (RAW)",
+                (2, 2) => "3:2",
+                (3, 1) => "16:9 (RAW)",
+                (3, 3) => "16:9",
+                (4, 1) => "1:1 (RAW)",
+                (4, 4) => "6:6",
+                (5, 5) => "5:4",
+                (6, 6) => "7:6",
+                (7, 7) => "6:5",
+                (8, 8) => "7:5",
+                (9, 1) => "3:4 (RAW)",
+                (9, 9) => "3:4",
+                _ => $"Unknown ({values[0]} {values[1]})"
             };
             return ret;
         }
@@ -157,14 +156,12 @@ public sealed class OlympusImageProcessingMakernoteDescriptor(OlympusImageProces
             if (Directory.GetObject(OlympusImageProcessingMakernoteDirectory.TagKeystoneCompensation) is not byte[] values || values.Length < 2)
                 return null;
 
-            var join = $"{values[0]} {values[1]}";
-            var ret = join switch
+            return (values[0], values[1]) switch
             {
-                "0 0" => "Off",
-                "0 1" => "On",
-                _ => "Unknown (" + join + ")",
+                (0, 0) => "Off",
+                (0, 1) => "On",
+                _ => $"Unknown ({values[0]} {values[1]})"
             };
-            return ret;
         }
 
         public string? GetKeystoneDirectionDescription()

From 25d2fea113de9af0dc4055b0db217d7be3aa3a96 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 18:51:02 -0800
Subject: [PATCH 11/16] Use switch statement in
 OlympusFocusInfoMakernoteDescriptor.GetExternalFlashZoomDescription

---
 .../OlympusFocusInfoMakernoteDescriptor.cs       | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
index 467e2e141..a19d11b77 100644
--- a/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
+++ b/MetadataExtractor/Formats/Exif/makernotes/OlympusFocusInfoMakernoteDescriptor.cs
@@ -30,7 +30,7 @@ public sealed class OlympusFocusInfoMakernoteDescriptor(OlympusFocusInfoMakernot
                 OlympusFocusInfoMakernoteDirectory.TagMacroLed => GetMacroLedDescription(),
                 OlympusFocusInfoMakernoteDirectory.TagSensorTemperature => GetSensorTemperatureDescription(),
                 OlympusFocusInfoMakernoteDirectory.TagImageStabilization => GetImageStabilizationDescription(),
-                _ => base.GetDescription(tagType),
+                _ => base.GetDescription(tagType)
             };
         }
 
@@ -107,15 +107,13 @@ public sealed class OlympusFocusInfoMakernoteDescriptor(OlympusFocusInfoMakernot
             if (values.Length == 0)
                 return null;
 
-            var join = $"{values[0]}" + (values.Length > 1 ? $"{values[1]}" : "");
-
-            return join switch
+            return (values[0], values.Length > 1 ? values[1] : -1) switch
             {
-                "0" => "Off",
-                "1" => "On",
-                "0 0" => "Off",
-                "1 0" => "On",
-                _ => "Unknown (" + join + ")",
+                (0, -1) => "Off",
+                (1, -1) => "On",
+                (0, 0) => "Off",
+                (1, 0) => "On",
+                _ => $"Unknown ({string.Join(" ", values)})"
             };
         }
 

From f8ef4c4da2c2b2649c4b2d3556ff89537b64b804 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 18:51:28 -0800
Subject: [PATCH 12/16] Use pattern matching to simplify another string.Join
 condition

---
 MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs b/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
index 6e41763bc..920a87c22 100644
--- a/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
+++ b/MetadataExtractor/Formats/Heif/HeicImagePropertyDescriptor.cs
@@ -15,7 +15,7 @@ public class HeicImagePropertyDescriptor(HeicImagePropertiesDirectory directory)
                     return Directory.GetString(tagType) + " degrees";
                 case HeicImagePropertiesDirectory.TagPixelDepths:
                     var o = Directory.GetObject(HeicImagePropertiesDirectory.TagPixelDepths);
-                    return o is null ? null : string.Join(" ", ((byte[])o).Select(i => i.ToString()));
+                    return o is byte[] bytes ? string.Join(" ", bytes) : null;
                 case HeicImagePropertiesDirectory.TagColorFormat:
                     return TypeStringConverter.ToTypeString(Directory.GetUInt32(HeicImagePropertiesDirectory.TagColorFormat));
                 case HeicImagePropertiesDirectory.TagColorPrimaries:

From 76f35fae7ce282220ad8178641621f47abd2a1d2 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 18:51:35 -0800
Subject: [PATCH 13/16] Simplify GetString call

---
 MetadataExtractor/Formats/Photoshop/PhotoshopDescriptor.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/Photoshop/PhotoshopDescriptor.cs b/MetadataExtractor/Formats/Photoshop/PhotoshopDescriptor.cs
index e0986a45a..e2674893a 100644
--- a/MetadataExtractor/Formats/Photoshop/PhotoshopDescriptor.cs
+++ b/MetadataExtractor/Formats/Photoshop/PhotoshopDescriptor.cs
@@ -283,7 +283,7 @@ public sealed class PhotoshopDescriptor(PhotoshopDirectory directory)
 
             return bytes is null
                 ? null
-                : Encoding.UTF8.GetString(bytes, 0, bytes.Length);
+                : Encoding.UTF8.GetString(bytes);
         }
 
         private string? GetBinaryDataString(int tagType)

From 48f9cba3a874561dd7f76aedbb9b35c6aa7dc2e5 Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 18:57:37 -0800
Subject: [PATCH 14/16] Use Encoding.ASCII.GetString

---
 .../Formats/QuickTime/QuickTimeReaderExtensions.cs              | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs b/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
index 17f3be52e..4bba9909e 100644
--- a/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
+++ b/MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs
@@ -13,7 +13,7 @@ public static string Get4ccString(this SequentialReader reader)
 
             reader.GetBytes(bytes);
 
-            return new string([(char)bytes[0], (char)bytes[1], (char)bytes[2], (char)bytes[3]]);
+            return Encoding.ASCII.GetString(bytes);
         }
 
         public static decimal Get16BitFixedPoint(this SequentialReader reader)

From 446e295ea1c696456b328ad44efa34ffa370484c Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 19:03:49 -0800
Subject: [PATCH 15/16] Eliminate byte[] allocation in RiffReader

---
 MetadataExtractor/Formats/Riff/RiffReader.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/MetadataExtractor/Formats/Riff/RiffReader.cs b/MetadataExtractor/Formats/Riff/RiffReader.cs
index 8e1ea022f..ed2f329a8 100644
--- a/MetadataExtractor/Formats/Riff/RiffReader.cs
+++ b/MetadataExtractor/Formats/Riff/RiffReader.cs
@@ -57,6 +57,8 @@ private static void ProcessChunks(SequentialReader reader, long maxPosition, IRi
         {
             // Processing chunks. Each chunk is 8 bytes header (4 bytes CC code + 4 bytes length of chunk) + data of the chunk
 
+            Span<byte> listName = stackalloc byte[4];
+
             while (reader.Position < maxPosition - 8)
             {
                 string chunkFourCc = reader.GetString(4, Encoding.ASCII);
@@ -70,7 +72,7 @@ private static void ProcessChunks(SequentialReader reader, long maxPosition, IRi
                 {
                     if (chunkSize < 4)
                         break;
-                    ReadOnlySpan<byte> listName = reader.GetBytes(4);
+                    listName = reader.GetBytes(4);
                     if (handler.ShouldAcceptList(listName))
                         ProcessChunks(reader, reader.Position + chunkSize - 4, handler);
                     else

From 21f5e474cb09d15d93c9790dbe399496f45e645c Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Mon, 29 Jan 2024 19:10:39 -0800
Subject: [PATCH 16/16] Eliminate string allocation in Iso2022Converter

---
 MetadataExtractor/Formats/Iptc/Iso2022Converter.cs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs b/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
index 33f12ecce..e49d08d3a 100644
--- a/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
+++ b/MetadataExtractor/Formats/Iptc/Iso2022Converter.cs
@@ -1,5 +1,7 @@
 // Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
+using System.Buffers;
+
 namespace MetadataExtractor.Formats.Iptc
 {
     public static class Iso2022Converter
@@ -89,10 +91,13 @@ public static class Iso2022Converter
 
             foreach (var encoding in encodings)
             {
+                char[] charBuffer = ArrayPool<char>.Shared.Rent(encoding.GetMaxCharCount(bytes.Length));
+
                 try
                 {
-                    var s = encoding.GetString(bytes);
-                    if (s.IndexOf((char)65533) != -1)
+                    int charCount = encoding.GetChars(bytes, 0, bytes.Length, charBuffer, 0);
+
+                    if (charBuffer.AsSpan(0, charCount).IndexOf((char)65533) != -1)
                         continue;
                     return encoding;
                 }
@@ -100,6 +105,10 @@ public static class Iso2022Converter
                 {
                     // fall through...
                 }
+                finally
+                {
+                    ArrayPool<char>.Shared.Return(charBuffer);
+                }
             }
 
             // No encodings succeeded. Return null.