Miscellaneous minor changes

src/UglyToad.PdfPig.Core/IndirectReference.cs

@@ -53,5 +53,17 @@
         {
             return $"{ObjectNumber} {Generation}";
         }
+        
+        /// <inheritdoc/>
+        public static bool operator ==(IndirectReference left, IndirectReference right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator !=(IndirectReference left, IndirectReference right)
+        {
+            return !(left == right);
+        }
     }
 }

src/UglyToad.PdfPig.Core/PdfLine.cs

@@ -10,7 +10,7 @@
     /// The Y-axis extends vertically upwards and the X-axis horizontally to the right.
     /// Unless otherwise specified on a per-page basis, units in PDF space are equivalent to a typographic point (1/72 inch).
     /// </remarks>
-    public readonly struct PdfLine
+    public readonly struct PdfLine : IEquatable<PdfLine>
     {
         /// <summary>
         /// Length of the line.
@@ -70,14 +70,17 @@
         /// <summary>
         /// Returns a value indicating whether this <see cref="PdfLine"/> is equal to a specified <see cref="PdfLine"/> .
         /// </summary>
-        /// <param name="obj"></param>
         public override bool Equals(object obj)
         {
-            if (obj is PdfLine line)
-            {
-                return line.Point1.Equals(Point1) && line.Point2.Equals(Point2);
-            }
-            return false;
+            return obj is PdfLine other && Equals(other);
+        }
+
+        /// <summary>
+        /// Returns a value indicating whether this <see cref="PdfLine"/> is equal to a specified <see cref="PdfLine"/> .
+        /// </summary>
+        public bool Equals(PdfLine other)
+        {
+            return Point1.Equals(other.Point1) && Point2.Equals(other.Point2);
         }
 
         /// <summary>
@@ -87,5 +90,17 @@
         {
             return HashCode.Combine(Point1, Point2);
         }
+
+        /// <inheritdoc/>
+        public static bool operator ==(PdfLine left, PdfLine right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator !=(PdfLine left, PdfLine right)
+        {
+            return !(left == right);
+        }
     }
 }

src/UglyToad.PdfPig.Core/PdfPoint.cs

@@ -12,7 +12,7 @@
     /// The Y-axis extends vertically upwards and the X-axis horizontally to the right.
     /// Unless otherwise specified on a per-page basis, units in PDF space are equivalent to a typographic point (1/72 inch).
     /// </remarks>
-    public readonly struct PdfPoint
+    public readonly struct PdfPoint : IEquatable<PdfPoint>
     {
         /// <summary>
         /// The origin of the coordinates system.
@@ -83,14 +83,17 @@
         /// <summary>
         /// Returns a value indicating whether this <see cref="PdfPoint"/> is equal to a specified <see cref="PdfPoint"/> .
         /// </summary>
-        /// <param name="obj"></param>
         public override bool Equals(object obj)
         {
-            if (obj is PdfPoint point)
-            {
-                return point.X == X && point.Y == Y;
-            }
-            return false;
+            return obj is PdfPoint other && Equals(other);
+        }
+
+        /// <summary>
+        /// Returns a value indicating whether this <see cref="PdfPoint"/> is equal to a specified <see cref="PdfPoint"/> .
+        /// </summary>
+        public bool Equals(PdfPoint other)
+        {
+            return X.Equals(other.X) && Y.Equals(other.Y);
         }
 
         /// <summary>
@@ -106,5 +109,17 @@
         {
             return $"(x:{X.ToString(CultureInfo.InvariantCulture)}, y:{Y.ToString(CultureInfo.InvariantCulture)})";
         }
+
+        /// <inheritdoc/>
+        public static bool operator ==(PdfPoint left, PdfPoint right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator !=(PdfPoint left, PdfPoint right)
+        {
+            return !(left == right);
+        }
     }
 }

src/UglyToad.PdfPig.Core/PdfRectangle.cs

@@ -11,7 +11,7 @@
     /// The Y-axis extends vertically upwards and the X-axis horizontally to the right.
     /// Unless otherwise specified on a per-page basis, units in PDF space are equivalent to a typographic point (1/72 inch).
     /// </remarks>
-    public readonly struct PdfRectangle
+    public readonly struct PdfRectangle : IEquatable<PdfRectangle>
     {
         /// <summary>
         /// Top left point of the rectangle.
@@ -166,5 +166,38 @@
         {
             return $"[{TopLeft}, {Width.ToString(CultureInfo.InvariantCulture)}, {Height.ToString(CultureInfo.InvariantCulture)}]";
         }
+
+        /// <inheritdoc />
+        public bool Equals(PdfRectangle other)
+        {
+            return TopLeft.Equals(other.TopLeft) &&
+                   TopRight.Equals(other.TopRight) &&
+                   BottomRight.Equals(other.BottomRight) &&
+                   BottomLeft.Equals(other.BottomLeft);
+        }
+
+        /// <inheritdoc />
+        public override bool Equals(object obj)
+        {
+            return obj is PdfRectangle other && Equals(other);
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(TopLeft, TopRight, BottomRight, BottomLeft);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator ==(PdfRectangle left, PdfRectangle right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator !=(PdfRectangle left, PdfRectangle right)
+        {
+            return !(left == right);
+        }
     }
 }

src/UglyToad.PdfPig.Core/StreamInputBytes.cs

@@ -32,17 +32,17 @@
         {
             if (stream == null)
             {
-                throw new ArgumentNullException();
+                throw new ArgumentNullException(nameof(stream));
             }
 
             if (!stream.CanRead)
             {
-                throw new ArgumentException("The provided stream did not support reading.");
+                throw new ArgumentException("The provided stream did not support reading.", nameof(stream));
             }
 
             if (!stream.CanSeek)
             {
-                throw new ArgumentException("The provided stream did not support seeking.");
+                throw new ArgumentException("The provided stream did not support seeking.", nameof(stream));
             }
 
             this.stream = stream;

src/UglyToad.PdfPig.Core/TransformationMatrix.cs

@@ -6,7 +6,7 @@
     /// <summary>
     /// Specifies the conversion from the transformed coordinate space to the original untransformed coordinate space.
     /// </summary>
-    public readonly struct TransformationMatrix
+    public readonly struct TransformationMatrix : IEquatable<TransformationMatrix>
     {
         /// <summary>
         /// The default <see cref="TransformationMatrix"/>.
@@ -465,12 +465,21 @@
         /// <inheritdoc />
         public override bool Equals(object obj)
         {
-            if (!(obj is TransformationMatrix m))
-            {
-                return false;
-            }
+            return obj is TransformationMatrix other && Equals(other);
+        }
 
-            return Equals(this, m);
+        /// <inheritdoc />
+        public bool Equals(TransformationMatrix other)
+        {
+            return row1.Equals(other.row1) &&
+                   row2.Equals(other.row2) &&
+                   row3.Equals(other.row3) &&
+                   A.Equals(other.A) &&
+                   B.Equals(other.B) &&
+                   C.Equals(other.C) &&
+                   D.Equals(other.D) &&
+                   E.Equals(other.E) &&
+                   F.Equals(other.F);
         }
 
         /// <summary>
@@ -478,25 +487,13 @@
         /// </summary>
         public static bool Equals(TransformationMatrix a, TransformationMatrix b)
         {
-            for (var i = 0; i < Rows; i++)
-            {
-                for (var j = 0; j < Columns; j++)
-                {
-                    if (a[i, j] != b[i, j])
-                    {
-                        return false;
-                    }
-                }
-            }
-
-            return true;
+            return a.Equals(b);
         }
 
         /// <inheritdoc />
         public override int GetHashCode()
         {
             var hashCode = new HashCode();
-
             hashCode.Add(row1);
             hashCode.Add(row2);
             hashCode.Add(row3);
@@ -506,7 +503,6 @@
             hashCode.Add(D);
             hashCode.Add(E);
             hashCode.Add(F);
-
             return hashCode.ToHashCode();
         }
 

src/UglyToad.PdfPig.DocumentLayoutAnalysis/TextExtractor/ContentOrderTextExtractor.cs

@@ -187,7 +187,7 @@
             /// <summary>
             /// When parsing PDF files with tables containing multiple lines in a cell or "merged" cells,
             /// the separate words can appear out of horizontal order. This option can better predict the
-            //  spaces between the words. Default <see langword="false"/>.
+            ///  spaces between the words. Default <see langword="false"/>.
             /// </summary>
             public bool NegativeGapAsWhitespace { get; set; }
         }

src/UglyToad.PdfPig.Fonts/TrueType/Glyphs/CompositeTransformMatrix3By2.cs

@@ -22,7 +22,7 @@ namespace UglyToad.PdfPig.Fonts.TrueType.Glyphs
             r2c1 = r2C1;
         }
 
-        public static CompositeTransformMatrix3By2 Identity { get; } = new CompositeTransformMatrix3By2(1, 0, 0, 1, 0, 0);
+        public static readonly CompositeTransformMatrix3By2 Identity = new CompositeTransformMatrix3By2(1, 0, 0, 1, 0, 0);
         public static CompositeTransformMatrix3By2 CreateTranslation(double x, double y) => new CompositeTransformMatrix3By2(1, 0, 0, 1, x, y);
 
         public CompositeTransformMatrix3By2 WithTranslation(double x, double y)

src/UglyToad.PdfPig.Tokenization/DictionaryTokenizer.cs

@@ -183,7 +183,7 @@
             return result;
         }
 
-        private static IToken PeekNext(IReadOnlyList<IToken> tokens, int currentIndex)
+        private static IToken PeekNext(List<IToken> tokens, int currentIndex)
         {
             if (tokens.Count - 1 < currentIndex + 1)
             {

src/UglyToad.PdfPig/Functions/Type4/Parser.cs

@@ -6,7 +6,7 @@
     /// Parser for PDF Type 4 functions. This implements a small subset of the PostScript
     /// language but is no full PostScript interpreter.
     /// </summary>
-    internal sealed class Parser
+    internal static class Parser
     {
         /// <summary>
         /// Used to indicate the parsers current state.
@@ -16,11 +16,6 @@
             NEWLINE, WHITESPACE, COMMENT, TOKEN
         }
 
-        private Parser()
-        {
-            //nop
-        }
-
         /// <summary>
         /// Parses a Type 4 function and sends the syntactic elements to the given syntax handler.
         /// </summary>

src/UglyToad.PdfPig/Graphics/Colors/ColorSpaceDetails.cs

@@ -317,6 +317,9 @@
         /// </summary>
         public ReadOnlySpan<byte> ColorTable => colorTable;
 
+        /// <summary>
+        /// Create a new <see cref="IndexedColorSpaceDetails"/>.
+        /// </summary>
         public IndexedColorSpaceDetails(ColorSpaceDetails baseColorSpaceDetails, byte hiVal, byte[] colorTable)
             : this(baseColorSpaceDetails, hiVal, colorTable, false)
         { }

src/UglyToad.PdfPig/Images/Png/Pixel.cs

@@ -5,7 +5,7 @@
     /// <summary>
     /// A pixel in a <see cref="Png"/> image.
     /// </summary>
-    internal readonly struct Pixel
+    internal readonly struct Pixel : IEquatable<Pixel>
     {
         /// <summary>
         /// The red value for the pixel.
@@ -104,5 +104,17 @@
         {
             return $"({R}, {G}, {B}, {A})";
         }
+
+        /// <inheritdoc/>
+        public static bool operator ==(Pixel left, Pixel right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <inheritdoc/>
+        public static bool operator !=(Pixel left, Pixel right)
+        {
+            return !(left == right);
+        }
     }
 }

src/UglyToad.PdfPig/Parser/FileStructure/CrossReferenceTableParser.cs

@@ -8,6 +8,7 @@
     using Tokenization;
     using Tokenization.Scanner;
     using Tokens;
+    using UglyToad.PdfPig.Util;
 
     internal static class CrossReferenceTableParser
     {
@@ -124,7 +125,7 @@
                     && (operatorToken.Data == OperatorToken.Xref.Data
                         || (isLenientParsing 
                             && operatorToken.Data.StartsWith(OperatorToken.Xref.Data)
-                            && int.TryParse(operatorToken.Data.Substring(OperatorToken.Xref.Data.Length), out _))));
+                            && int.TryParse(operatorToken.Data.AsSpanOrSubstring(OperatorToken.Xref.Data.Length), out _))));
         }
 
         private static int ProcessTokens(ReadOnlySpan<IToken> tokens, CrossReferenceTablePartBuilder builder, bool isLenientParsing,

src/UglyToad.PdfPig/Parser/FileStructure/FileHeaderParser.cs

@@ -64,7 +64,7 @@
 
         private static HeaderVersion GetHeaderVersionAndResetScanner(CommentToken comment, ISeekableTokenScanner scanner, bool isLenientParsing, ILog log)
         {
-            if (comment.Data.IndexOf("PDF-1.", StringComparison.OrdinalIgnoreCase) != 0 && comment.Data.IndexOf("FDF-1.", StringComparison.OrdinalIgnoreCase) != 0)
+            if (!comment.Data.StartsWith("PDF-1.", StringComparison.OrdinalIgnoreCase) && !comment.Data.StartsWith("FDF-1.", StringComparison.OrdinalIgnoreCase))
             {
                 return HandleMissingVersion(comment, isLenientParsing, log);
             }

src/UglyToad.PdfPig/Parser/FileStructure/XrefOffsetValidator.cs

@@ -148,7 +148,7 @@
         {
             newOffset = -1;
             BruteForceSearchForStartxref(reader);
-            long newStartXRefOffset = SearchNearestValue(bfSearchStartXRefTablesOffsets, xrefOffset);
+            long newStartXRefOffset = SearchNearestValue(bfSearchStartXRefTablesOffsets!, xrefOffset);
             if (newStartXRefOffset < reader.Length)
             {
                 long tempNewOffset = -1;

src/UglyToad.PdfPig/Parser/Parts/CrossReference/CrossReferenceStreamParser.cs

@@ -137,7 +137,7 @@
             }
         }
 
-        private static IEnumerable<long> GetObjectNumbers(DictionaryToken dictionary)
+        private static ReadOnlySpan<long> GetObjectNumbers(DictionaryToken dictionary)
         {
             //  The number one greater than the highest object number used in this section or in any section for which this is an update.
             if (!dictionary.TryGet(NameToken.Size, out var sizeToken) || !(sizeToken is NumericToken sizeNumeric))
@@ -170,7 +170,11 @@
                 }
             }
 
-            return objNums;
+#if NET
+            return System.Runtime.InteropServices.CollectionsMarshal.AsSpan(objNums);
+#else
+            return objNums.ToArray();
+#endif
         }
     }
 }

src/UglyToad.PdfPig/Tokenization/Scanner/ObjectLocationProvider.cs

@@ -88,7 +88,7 @@
         {
             if (objectToken is null)
             {
-                throw new ArgumentNullException();
+                throw new ArgumentNullException(nameof(objectToken));
             }
 
             // Don't cache incorrect locations.

src/UglyToad.PdfPig/Writer/PdfDedupStreamWriter.cs

@@ -5,7 +5,7 @@
     using System.IO;
     using Tokens;
 
-    internal class PdfDedupStreamWriter : PdfStreamWriter
+    internal sealed class PdfDedupStreamWriter : PdfStreamWriter
     {
         private readonly Dictionary<byte[], IndirectReferenceToken> hashes = new Dictionary<byte[], IndirectReferenceToken>(new FNVByteComparison());
 
@@ -69,7 +69,7 @@
             base.Dispose();
         }
 
-        class FNVByteComparison : IEqualityComparer<byte[]>
+        private sealed class FNVByteComparison : IEqualityComparer<byte[]>
         {
             public bool Equals(byte[] x, byte[] y)
             {
@@ -91,7 +91,7 @@
         /// <summary>
         /// A hash combiner that is implemented with the Fowler/Noll/Vo algorithm (FNV-1a). This is a mutable struct for performance reasons.
         /// </summary>
-        struct FnvHash
+        private struct FnvHash
         {
             /// <summary>
             /// The starting point of the FNV hash.
@@ -113,9 +113,10 @@
             /// </summary>
             public static FnvHash Create()
             {
-                var result = new FnvHash();
-                result.HashCode = Offset;
-                return result;
+                return new FnvHash
+                {
+                    HashCode = Offset
+                };
             }
 
             /// <summary>