Merge pull request #416 from iamcarbon/bplist1

Spanify BplistReader
drewnoakes · Feb 23, 2024 · 5fe5981 · 5fe5981
2 parents ec5fe3c + 3cccae2
commit 5fe5981
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Showing 6 changed files with 18 additions and 33 deletions.
diff --git a/MetadataExtractor/Formats/Apple/BplistReader.cs b/MetadataExtractor/Formats/Apple/BplistReader.cs
@@ -11,42 +11,27 @@ public sealed class BplistReader
     // https://opensource.apple.com/source/CF/CF-550/CFBinaryPList.c
     // https://synalysis.com/how-to-decode-apple-binary-property-list-files/
 
-    private static ReadOnlySpan<byte> BplistHeader => "bplist00"u8;
-
     /// <summary>
     /// Gets whether <paramref name="bplist"/> starts with the expected header bytes.
     /// </summary>
-    public static bool IsValid(byte[] bplist)
+    public static bool IsValid(ReadOnlySpan<byte> bplist)
     {
-        if (bplist.Length < BplistHeader.Length)
-        {
-            return false;
-        }
-
-        for (int i = 0; i < BplistHeader.Length; i++)
-        {
-            if (bplist[i] != BplistHeader[i])
-            {
-                return false;
-            }
-        }
-
-        return true;
+        return bplist.StartsWith("bplist00"u8);
     }
 
-    public static PropertyListResults Parse(byte[] bplist)
+    public static PropertyListResults Parse(ReadOnlySpan<byte> bplist)
     {
         if (!IsValid(bplist))
         {
             throw new ArgumentException("Input is not a bplist.", nameof(bplist));
         }
 
-        Trailer trailer = ReadTrailer();
+        Trailer trailer = ReadTrailer(bplist);
 
         int offset = checked((int)(trailer.OffsetTableOffset + trailer.TopObject));
-        var reader = new BufferReader(bplist.AsSpan(offset), isBigEndian: true);
+        var reader = new BufferReader(bplist.Slice(offset), isBigEndian: true);
 
-        int[] offsets = new int[(int)trailer.NumObjects];
+        var offsets = new int[(int)trailer.NumObjects];
 
         for (int i = 0; i < (int)trailer.NumObjects; i++)
         {
@@ -64,7 +49,7 @@ public static PropertyListResults Parse(byte[] bplist)
 
         for (int i = 0; i < offsets.Length; i++)
         {
-            reader = new BufferReader(bplist.AsSpan(offsets[i]), isBigEndian: true);
+            reader = new BufferReader(bplist.Slice(offsets[i]), isBigEndian: true);
 
             byte b = reader.GetByte();
 
@@ -90,9 +75,9 @@ public static PropertyListResults Parse(byte[] bplist)
 
         return new PropertyListResults(objects, trailer);
 
-        Trailer ReadTrailer()
+        static Trailer ReadTrailer(ReadOnlySpan<byte> bplist)
         {
-            var reader = new BufferReader(bplist.AsSpan(bplist.Length - Trailer.SizeBytes), isBigEndian: true);
+            var reader = new BufferReader(bplist.Slice(bplist.Length - Trailer.SizeBytes), isBigEndian: true);
 
             // Skip 5-byte unused values, 1-byte sort version.
             reader.Skip(5 + 1);

diff --git a/MetadataExtractor/Formats/Exif/Makernotes/AppleRunTimeMakernoteDirectory.cs b/MetadataExtractor/Formats/Exif/Makernotes/AppleRunTimeMakernoteDirectory.cs
@@ -11,7 +11,7 @@ public sealed class AppleRunTimeMakernoteDirectory : Directory
     public const int TagScale = 3;
     public const int TagValue = 4;
 
-    private static readonly Dictionary<int, string> _tagNameMap = new();
+    private static readonly Dictionary<int, string> _tagNameMap = new(4);
 
     static AppleRunTimeMakernoteDirectory()
     {

diff --git a/MetadataExtractor/PublicAPI/net462/PublicAPI.Unshipped.txt b/MetadataExtractor/PublicAPI/net462/PublicAPI.Unshipped.txt
@@ -132,8 +132,8 @@ override MetadataExtractor.IO.IndexedCapturingReader.GetBytes(int index, System.
 override MetadataExtractor.IO.IndexedSeekingReader.GetBytes(int index, System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialByteArrayReader.GetBytes(System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialStreamReader.GetBytes(System.Span<byte> bytes) -> void
-static MetadataExtractor.Formats.Apple.BplistReader.IsValid(byte[]! bplist) -> bool
-static MetadataExtractor.Formats.Apple.BplistReader.Parse(byte[]! bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
+static MetadataExtractor.Formats.Apple.BplistReader.IsValid(System.ReadOnlySpan<byte> bplist) -> bool
+static MetadataExtractor.Formats.Apple.BplistReader.Parse(System.ReadOnlySpan<byte> bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
 static MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory.Parse(byte[]! bytes) -> MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory!
 static MetadataExtractor.Formats.Png.PngChunkType.operator !=(MetadataExtractor.Formats.Png.PngChunkType left, MetadataExtractor.Formats.Png.PngChunkType right) -> bool
 static MetadataExtractor.Formats.Png.PngChunkType.operator ==(MetadataExtractor.Formats.Png.PngChunkType left, MetadataExtractor.Formats.Png.PngChunkType right) -> bool

diff --git a/MetadataExtractor/PublicAPI/net8.0/PublicAPI.Unshipped.txt b/MetadataExtractor/PublicAPI/net8.0/PublicAPI.Unshipped.txt
@@ -131,8 +131,8 @@ override MetadataExtractor.IO.IndexedCapturingReader.GetBytes(int index, System.
 override MetadataExtractor.IO.IndexedSeekingReader.GetBytes(int index, System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialByteArrayReader.GetBytes(System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialStreamReader.GetBytes(System.Span<byte> bytes) -> void
-static MetadataExtractor.Formats.Apple.BplistReader.IsValid(byte[]! bplist) -> bool
-static MetadataExtractor.Formats.Apple.BplistReader.Parse(byte[]! bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
+static MetadataExtractor.Formats.Apple.BplistReader.IsValid(System.ReadOnlySpan<byte> bplist) -> bool
+static MetadataExtractor.Formats.Apple.BplistReader.Parse(System.ReadOnlySpan<byte> bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
 static MetadataExtractor.Formats.Exif.ExifReader.JpegSegmentPreamble.get -> System.ReadOnlySpan<byte>
 static MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory.Parse(byte[]! bytes) -> MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory!
 static MetadataExtractor.Formats.Icc.IccReader.JpegSegmentPreamble.get -> System.ReadOnlySpan<byte>

diff --git a/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Unshipped.txt b/MetadataExtractor/PublicAPI/netstandard1.3/PublicAPI.Unshipped.txt
@@ -132,8 +132,8 @@ override MetadataExtractor.IO.IndexedCapturingReader.GetBytes(int index, System.
 override MetadataExtractor.IO.IndexedSeekingReader.GetBytes(int index, System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialByteArrayReader.GetBytes(System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialStreamReader.GetBytes(System.Span<byte> bytes) -> void
-static MetadataExtractor.Formats.Apple.BplistReader.IsValid(byte[]! bplist) -> bool
-static MetadataExtractor.Formats.Apple.BplistReader.Parse(byte[]! bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
+static MetadataExtractor.Formats.Apple.BplistReader.IsValid(System.ReadOnlySpan<byte> bplist) -> bool
+static MetadataExtractor.Formats.Apple.BplistReader.Parse(System.ReadOnlySpan<byte> bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
 static MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory.Parse(byte[]! bytes) -> MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory!
 static MetadataExtractor.Formats.Png.PngChunkType.operator !=(MetadataExtractor.Formats.Png.PngChunkType left, MetadataExtractor.Formats.Png.PngChunkType right) -> bool
 static MetadataExtractor.Formats.Png.PngChunkType.operator ==(MetadataExtractor.Formats.Png.PngChunkType left, MetadataExtractor.Formats.Png.PngChunkType right) -> bool

diff --git a/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Unshipped.txt b/MetadataExtractor/PublicAPI/netstandard2.1/PublicAPI.Unshipped.txt
@@ -131,8 +131,8 @@ override MetadataExtractor.IO.IndexedCapturingReader.GetBytes(int index, System.
 override MetadataExtractor.IO.IndexedSeekingReader.GetBytes(int index, System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialByteArrayReader.GetBytes(System.Span<byte> bytes) -> void
 override MetadataExtractor.IO.SequentialStreamReader.GetBytes(System.Span<byte> bytes) -> void
-static MetadataExtractor.Formats.Apple.BplistReader.IsValid(byte[]! bplist) -> bool
-static MetadataExtractor.Formats.Apple.BplistReader.Parse(byte[]! bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
+static MetadataExtractor.Formats.Apple.BplistReader.IsValid(System.ReadOnlySpan<byte> bplist) -> bool
+static MetadataExtractor.Formats.Apple.BplistReader.Parse(System.ReadOnlySpan<byte> bplist) -> MetadataExtractor.Formats.Apple.BplistReader.PropertyListResults!
 static MetadataExtractor.Formats.Exif.ExifReader.JpegSegmentPreamble.get -> System.ReadOnlySpan<byte>
 static MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory.Parse(byte[]! bytes) -> MetadataExtractor.Formats.Exif.Makernotes.AppleRunTimeMakernoteDirectory!
 static MetadataExtractor.Formats.Icc.IccReader.JpegSegmentPreamble.get -> System.ReadOnlySpan<byte>