Merge remote-tracking branch 'origin/main' into cq4

.editorconfig

@@ -3,6 +3,7 @@ root = true
 [*]
 
 # Spell checker configuration
+spelling_languages = en-us,en-gb
 spelling_exclusion_path = spelling.dic
 
 [*.cs]

MetadataExtractor/Formats/Apple/BplistReader.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.Apple;
 
 /// <summary>
@@ -121,7 +123,7 @@ static object HandleInt(ref BufferReader reader, byte marker)
 
         static Dictionary<byte, byte> HandleDict(ref BufferReader reader, byte count)
         {
-            var keyRefs = new byte[count];
+            var keyRefs = ArrayPool<byte>.Shared.Rent(count);
 
             for (int j = 0; j < count; j++)
             {
@@ -135,6 +137,8 @@ static Dictionary<byte, byte> HandleDict(ref BufferReader reader, byte count)
                 map.Add(keyRefs[j], reader.GetByte());
             }
 
+            ArrayPool<byte>.Shared.Return(keyRefs);
+
             return map;
         }
 

MetadataExtractor/Formats/Exif/ExifTiffHandler.cs

@@ -385,7 +385,7 @@ public override void EndingIfd(in TiffReaderContext context)
                 if (directory.GetObject(ExifDirectoryBase.TagGeoTiffGeoKeys) is ushort[] geoKeys)
                 {
                     // GetTIFF stores data in its own format within TIFF. It is TIFF-like, but different.
-                    // It can reference data frm tags that have not been visited yet, so we must unpack it
+                    // It can reference data from tags that have not been visited yet, so we must unpack it
                     // once the directory is complete.
                     ProcessGeoTiff(geoKeys, directory);
                 }

MetadataExtractor/Formats/Flir/FlirReader.cs

@@ -1,5 +1,6 @@
 // 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;
 using MetadataExtractor.Formats.Jpeg;
 using static MetadataExtractor.Formats.Flir.FlirCameraInfoDirectory;
 
@@ -35,26 +36,35 @@ public IEnumerable<Directory> ReadJpegSegments(IEnumerable<JpegSegment> segments
             if (length == 0)
                 return [];
 
-            var buffer = new byte[length];
-            using var merged = new MemoryStream(buffer);
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
 
-            foreach (var segment in segments)
+            try
             {
-                // Skip segments not starting with the required preamble
-                if (segment.Span.StartsWith(preamble))
+                using var merged = new MemoryStream(buffer);
+
+                foreach (var segment in segments)
                 {
-                    merged.Write(segment.Bytes, preambleLength, segment.Bytes.Length - preambleLength);
+                    // Skip segments not starting with the required preamble
+                    if (segment.Span.StartsWith(preamble))
+                    {
+                        merged.Write(segment.Bytes, preambleLength, segment.Bytes.Length - preambleLength);
+                    }
                 }
-            }
 
-            return Extract(new ByteArrayReader(buffer));
+                return Extract(new ByteArrayReader(buffer));
+            }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public IEnumerable<Directory> Extract(IndexedReader reader)
         {
-            var header = reader.GetUInt32(0);
+            Span<byte> header = stackalloc byte[4];
+            reader.GetBytes(0, header);
 
-            if (header != 0x46464600)
+            if (!header.SequenceEqual("FFF\0"u8))
             {
                 var flirHeaderDirectory = new FlirHeaderDirectory();
                 flirHeaderDirectory.AddError("Unexpected FFF header bytes.");

MetadataExtractor/Formats/Gif/GifReader.cs

@@ -1,5 +1,6 @@
 // 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;
 using MetadataExtractor.Formats.Icc;
 using MetadataExtractor.Formats.Xmp;
 
@@ -234,45 +235,42 @@ private static GifCommentDirectory ReadCommentBlock(SequentialReader reader, byt
             if (blockSizeBytes != 11)
                 return new ErrorDirectory($"Invalid GIF application extension block size. Expected 11, got {blockSizeBytes}.");
 
-            var extensionType = reader.GetString(blockSizeBytes, Encoding.UTF8);
+            Span<byte> extensionType = stackalloc byte[11];
 
-            switch (extensionType)
+            reader.GetBytes(extensionType);
+
+            if (extensionType.SequenceEqual("XMP DataXMP"u8))
             {
-                case "XMP DataXMP":
-                {
-                    // XMP data extension
-                    var xmpBytes = GatherBytes(reader);
-                    int xmpLength = xmpBytes.Length - 257; // Exclude the "magic trailer", see XMP Specification Part 3, 1.1.2 GIF
-                    // Only extract valid blocks
-                    return xmpLength > 0
-                        ? new XmpReader().Extract(xmpBytes, 0, xmpBytes.Length - 257)
-                        : null;
-                }
-                case "ICCRGBG1012":
-                {
-                    // ICC profile extension
-                    var iccBytes = GatherBytes(reader, reader.GetByte());
-                    return iccBytes.Length != 0
-                        ? new IccReader().Extract(new ByteArrayReader(iccBytes))
-                        : null;
-                }
-                case "NETSCAPE2.0":
-                {
-                    reader.Skip(2);
-                    // Netscape's animated GIF extension
-                    // Iteration count (0 means infinite)
-                    var iterationCount = reader.GetUInt16();
-                    // Skip terminator
-                    reader.Skip(1);
-                    var animationDirectory = new GifAnimationDirectory();
-                    animationDirectory.Set(GifAnimationDirectory.TagIterationCount, iterationCount);
-                    return animationDirectory;
-                }
-                default:
-                {
-                    SkipBlocks(reader);
-                    return null;
-                }
+                // XMP data extension
+                var xmpBytes = GatherXmpBytes(reader);
+                return xmpBytes is not null
+                    ? new XmpReader().Extract(xmpBytes)
+                    : null;
+            }
+            else if (extensionType.SequenceEqual("ICCRGBG1012"u8))
+            {
+                // ICC profile extension
+                var iccBytes = GatherBytes(reader, reader.GetByte());
+                return iccBytes.Length != 0
+                    ? new IccReader().Extract(new ByteArrayReader(iccBytes))
+                    : null;
+            }
+            else if (extensionType.SequenceEqual("NETSCAPE2.0"u8))
+            {
+                reader.Skip(2);
+                // Netscape's animated GIF extension
+                // Iteration count (0 means infinite)
+                var iterationCount = reader.GetUInt16();
+                // Skip terminator
+                reader.Skip(1);
+                var animationDirectory = new GifAnimationDirectory();
+                animationDirectory.Set(GifAnimationDirectory.TagIterationCount, iterationCount);
+                return animationDirectory;
+            }
+            else
+            {
+                SkipBlocks(reader);
+                return null;
             }
         }
 
@@ -329,36 +327,58 @@ private static GifImageDirectory ReadImageBlock(SequentialReader reader)
 
         #region Utility methods
 
-        private static byte[] GatherBytes(SequentialReader reader)
+        private static byte[]? GatherXmpBytes(SequentialReader reader)
         {
-            var bytes = new MemoryStream();
-            var buffer = new byte[257];
+            // GatherXmpBytes differs from GatherBytes in that this method includes the "length"
+            // bytes in its output.
+
+            var stream = new MemoryStream();
+            var buffer = ArrayPool<byte>.Shared.Rent(byte.MaxValue + 1);
 
             while (true)
             {
-                var b = reader.GetByte();
-                if (b == 0)
-                    return bytes.ToArray();
-                buffer[0] = b;
-                reader.GetBytes(buffer, 1, b);
-                bytes.Write(buffer, 0, b + 1);
+                var len = reader.GetByte();
+                if (len == 0)
+                    break;
+                buffer[0] = len;
+                reader.GetBytes(buffer, offset: 1, count: len);
+                stream.Write(buffer, 0, len + 1);
             }
+
+            ArrayPool<byte>.Shared.Return(buffer);
+
+            // Exclude the "magic trailer", see XMP Specification Part 3, 1.1.2 GIF
+            int xmpLength = checked((int)stream.Length) - 257;
+
+            if (xmpLength <= 0)
+            {
+                return null;
+            }
+
+            stream.SetLength(xmpLength);
+
+            return stream.ToArray();
         }
 
-        private static byte[] GatherBytes(SequentialReader reader, int firstLength)
+        private static byte[] GatherBytes(SequentialReader reader, byte firstLength)
         {
-            var buffer = new MemoryStream();
+            var stream = new MemoryStream();
+            var buffer = ArrayPool<byte>.Shared.Rent(byte.MaxValue);
 
             var length = firstLength;
 
             while (length > 0)
             {
-                buffer.Write(reader.GetBytes(length), 0, length);
+                reader.GetBytes(buffer.AsSpan().Slice(0, length));
+
+                stream.Write(buffer, 0, length);
 
                 length = reader.GetByte();
             }
 
-            return buffer.ToArray();
+            ArrayPool<byte>.Shared.Return(buffer);
+
+            return stream.ToArray();
         }
 
         private static void SkipBlocks(SequentialReader reader)

MetadataExtractor/Formats/Icc/IccReader.cs

@@ -1,5 +1,6 @@
 // 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;
 using MetadataExtractor.Formats.Jpeg;
 
 namespace MetadataExtractor.Formats.Icc
@@ -37,14 +38,14 @@ public IEnumerable<Directory> ReadJpegSegments(IEnumerable<JpegSegment> segments
             byte[] buffer;
             if (iccSegments.Count == 1)
             {
-                buffer = new byte[iccSegments[0].Bytes.Length - JpegSegmentPreambleLength];
+                buffer = ArrayPool<byte>.Shared.Rent(iccSegments[0].Bytes.Length - JpegSegmentPreambleLength);
                 Array.Copy(iccSegments[0].Bytes, JpegSegmentPreambleLength, buffer, 0, iccSegments[0].Bytes.Length - JpegSegmentPreambleLength);
             }
             else
             {
                 // Concatenate all buffers
                 var totalLength = iccSegments.Sum(s => s.Bytes.Length - JpegSegmentPreambleLength);
-                buffer = new byte[totalLength];
+                buffer = ArrayPool<byte>.Shared.Rent(totalLength);
                 for (int i = 0, pos = 0; i < iccSegments.Count; i++)
                 {
                     var segment = iccSegments[i];
@@ -53,7 +54,11 @@ public IEnumerable<Directory> ReadJpegSegments(IEnumerable<JpegSegment> segments
                 }
             }
 
-            return new Directory[] { Extract(new ByteArrayReader(buffer)) };
+            Directory directory = Extract(new ByteArrayReader(buffer));
+
+            ArrayPool<byte>.Shared.Return(buffer);
+
+            return [directory];
         }
 
         public IccDirectory Extract(IndexedReader reader)

MetadataExtractor/Formats/QuickTime/QuickTimeReaderExtensions.cs

@@ -7,29 +7,32 @@ namespace MetadataExtractor.Formats.QuickTime
     /// </summary>
     public static class QuickTimeReaderExtensions
     {
-#if NETSTANDARD2_1
-        public static string Get4ccString(this SequentialReader reader)
+#if NET462 || NETSTANDARD1_3
+        public static unsafe string Get4ccString(this SequentialReader reader)
 #else
-        public unsafe static string Get4ccString(this SequentialReader reader)
+        public static string Get4ccString(this SequentialReader reader)
 #endif
         {
+            // https://en.wikipedia.org/wiki/FourCC
+
             Span<byte> bytes = stackalloc byte[4];
             Span<char> chars = stackalloc char[4];
 
             reader.GetBytes(bytes);
 
+            // NOTE we cannot just use Encoding.ASCII here, as that can replace certain non-printable characters with '?'
             chars[0] = (char)bytes[0];
             chars[1] = (char)bytes[1];
             chars[2] = (char)bytes[2];
             chars[3] = (char)bytes[3];
 
-#if NETSTANDARD2_1
-            return new string(chars);
-#else
-            fixed (char* c = chars)
+#if NET462 || NETSTANDARD1_3
+            fixed (char* pChars = chars)
             {
-                return new string(c, 0, 4);
+                return new string(pChars, startIndex: 0, length: 4);
             }
+#else
+            return new string(chars);
 #endif
         }
 

MetadataExtractor/Formats/QuickTime/QuickTimeTypeChecker.cs

@@ -54,6 +54,9 @@ internal sealed class QuickTimeTypeChecker : ITypeChecker
             { Util.FileType.Heif, "hevc"u8 },
             { Util.FileType.Heif, "hevx"u8 },
 
+            // AVIF
+            { Util.FileType.Avif, "avif"u8 },
+
             // CRX
             { Util.FileType.Crx, "crx "u8 }
         };

MetadataExtractor/Formats/Raf/RafMetadataReader.cs

@@ -1,5 +1,6 @@
 // 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;
 using MetadataExtractor.Formats.Jpeg;
 
 namespace MetadataExtractor.Formats.Raf
@@ -14,7 +15,8 @@ public static IReadOnlyList<Directory> ReadMetadata(Stream stream)
             if (!stream.CanSeek)
                 throw new ArgumentException("Must support seek", nameof(stream));
 
-            var data = new byte[512];
+            var data = ArrayPool<byte>.Shared.Rent(512);
+
             var bytesRead = stream.Read(data, 0, 512);
 
             if (bytesRead == 0)
@@ -32,6 +34,8 @@ public static IReadOnlyList<Directory> ReadMetadata(Stream stream)
                 }
             }
 
+            ArrayPool<byte>.Shared.Return(data);
+
             return JpegMetadataReader.ReadMetadata(stream);
         }
     }

MetadataExtractor/Formats/Tga/TgaExtensionReader.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.Tga
 {
     /// <summary>Reads TGA image file extension area.</summary>
@@ -55,12 +57,7 @@ protected override void Populate(Stream stream, int offset, TgaExtensionDirector
 
             string GetString(int length)
             {
-                var buffer = new byte[length];
-                reader.GetBytes(buffer, 0, length);
-                int i = 0;
-                while (i < buffer.Length && buffer[i] != '\0')
-                    ++i;
-                return Encoding.ASCII.GetString(buffer, 0, i).TrimEnd();
+                return reader.GetNullTerminatedString(length, Encoding.ASCII, moveToMaxLength: true).TrimEnd();
             }
 
             bool TryGetDateTime(out DateTime dateTime)