Use singleton instances of encodings

dmester · Jul 9, 2023 · e93ec7f · e93ec7f
1 parent 6b198eb
commit e93ec7f
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Showing 15 changed files with 33 additions and 21 deletions.
diff --git a/src/PdfToSvg/DocumentModel/PdfStreamDebugProxy.cs b/src/PdfToSvg/DocumentModel/PdfStreamDebugProxy.cs
@@ -32,7 +32,7 @@ public string Content
                 {
                     using (var stream = streamInfo.OpenDecoded(CancellationToken.None))
                     {
-                        var encoding = new PdfDocEncoding();
+                        var encoding = SingleByteEncoding.PdfDoc;
                         var buffer = new byte[8 * 1024];
                         var read = stream.Read(buffer, 0, buffer.Length);
 

diff --git a/src/PdfToSvg/DocumentModel/PdfString.cs b/src/PdfToSvg/DocumentModel/PdfString.cs
@@ -196,7 +196,7 @@ public override string ToString()
                 return Encoding.BigEndianUnicode.GetString(data, 2, data.Length - 2);
             }
 
-            return new PdfDocEncoding().GetString(data);
+            return SingleByteEncoding.PdfDoc.GetString(data);
         }
 
         public string ToString(Encoding encoding) => encoding.GetString(data);

diff --git a/src/PdfToSvg/Encodings/EncodingFactory.cs b/src/PdfToSvg/Encodings/EncodingFactory.cs
@@ -19,17 +19,17 @@ internal static class EncodingFactory
             {
                 if (encodingName == Names.WinAnsiEncoding)
                 {
-                    return new WinAnsiEncoding();
+                    return SingleByteEncoding.WinAnsi;
                 }
 
                 if (encodingName == Names.MacExpertEncoding)
                 {
-                    return new MacExpertEncoding();
+                    return SingleByteEncoding.MacExpert;
                 }
 
                 if (encodingName == Names.MacRomanEncoding)
                 {
-                    return new MacRomanEncoding();
+                    return SingleByteEncoding.MacRoman;
                 }
             }
             else if (definition is PdfDictionary encodingDict)

diff --git a/src/PdfToSvg/Encodings/SingleByteEncoding.cs b/src/PdfToSvg/Encodings/SingleByteEncoding.cs
@@ -21,6 +21,18 @@ internal class SingleByteEncoding : Encoding
         private Lazy<Dictionary<string, byte>> fromUnicode;
         private Lazy<int> maxUnicodeLength;
 
+        private static SingleByteEncoding? standard;
+        private static SingleByteEncoding? pdfDoc;
+        private static SingleByteEncoding? winAnsi;
+        private static SingleByteEncoding? macExpert;
+        private static SingleByteEncoding? macRoman;
+
+        public static SingleByteEncoding Standard => standard ??= new StandardEncoding();
+        public static SingleByteEncoding PdfDoc => pdfDoc ??= new PdfDocEncoding();
+        public static SingleByteEncoding WinAnsi => winAnsi ??= new WinAnsiEncoding();
+        public static SingleByteEncoding MacExpert => macExpert ??= new MacExpertEncoding();
+        public static SingleByteEncoding MacRoman => macRoman ??= new MacRomanEncoding();
+
         internal SingleByteEncoding(string?[] toUnicode, string?[] toGlyphName)
         {
             if (toUnicode == null) throw new ArgumentNullException(nameof(toUnicode));

diff --git a/src/PdfToSvg/Fonts/BaseFont.cs b/src/PdfToSvg/Fonts/BaseFont.cs
@@ -89,7 +89,7 @@ protected virtual void OnInit(CancellationToken cancellationToken)
             }
 
             // Encoding
-            var baseEncoding = (isSymbolic ? openTypeFontEncoding : null) ?? new StandardEncoding();
+            var baseEncoding = (isSymbolic ? openTypeFontEncoding : null) ?? SingleByteEncoding.Standard;
             var encodingDefinition = fontDict.GetValueOrDefault(Names.Encoding);
             pdfFontEncoding = EncodingFactory.Create(encodingDefinition, baseEncoding);
 

diff --git a/src/PdfToSvg/Fonts/CompactFonts/CompactFont.cs b/src/PdfToSvg/Fonts/CompactFonts/CompactFont.cs
@@ -29,7 +29,7 @@ public CompactFont(CompactFontSet fontSet)
 
         public List<int> CharSet { get; } = new();
 
-        public SingleByteEncoding Encoding { get; set; } = new StandardEncoding();
+        public SingleByteEncoding Encoding { get; set; } = SingleByteEncoding.Standard;
 
         public List<CompactFontGlyph> Glyphs { get; } = new();
 

diff --git a/src/PdfToSvg/Fonts/CompactFonts/CompactFontParser.cs b/src/PdfToSvg/Fonts/CompactFonts/CompactFontParser.cs
@@ -152,12 +152,12 @@ private SingleByteEncoding ReadEncoding(CompactFont font, int offsetOrId)
 
             if (isCidFont || offsetOrId <= 0)
             {
-                return new StandardEncoding();
+                return SingleByteEncoding.Standard;
             }
 
             if (offsetOrId == 1)
             {
-                return new MacExpertEncoding();
+                return SingleByteEncoding.MacExpert;
             }
 
             reader.Position = offsetOrId;
@@ -351,7 +351,7 @@ private void ReplaceSeacChars(CompactFont font)
                 if (seac != null)
                 {
                     var content = glyph.CharString.Content;
-                    var standardEncoding = new StandardEncoding();
+                    var standardEncoding = SingleByteEncoding.Standard;
 
                     var acharValue = standardEncoding.GetString(new byte[] { (byte)seac.Achar });
                     var bcharValue = standardEncoding.GetString(new byte[] { (byte)seac.Bchar });

diff --git a/src/PdfToSvg/Fonts/OpenType/Tables/CffTable.cs b/src/PdfToSvg/Fonts/OpenType/Tables/CffTable.cs
@@ -27,7 +27,7 @@ public void Write(OpenTypeWriter writer)
                 // encoding has no meaning in an OpenType font.
                 foreach (var font in Content.Fonts)
                 {
-                    font.Encoding = new StandardEncoding();
+                    font.Encoding = SingleByteEncoding.Standard;
                 }
 
                 var data = CompactFontBuilder.Build(Content);

diff --git a/src/PdfToSvg/Fonts/TrueTypeFont.cs b/src/PdfToSvg/Fonts/TrueTypeFont.cs
@@ -47,7 +47,7 @@ protected override IEnumerable<CharInfo> GetChars()
             // ISO 32000-2 section 9.6.5.4
             var cmaps = openTypeFont?.CMaps ?? ArrayUtils.Empty<OpenTypeCMap>();
             var postGlyphNames = GetGlyphNameLookup();
-            var encoding = pdfFontEncoding ?? new StandardEncoding();
+            var encoding = pdfFontEncoding ?? SingleByteEncoding.Standard;
 
             var chars = Enumerable.Empty<CharInfo>();
 

diff --git a/src/PdfToSvg/Fonts/Type1/Type1Parser.cs b/src/PdfToSvg/Fonts/Type1/Type1Parser.cs
@@ -89,7 +89,7 @@ public Type1Parser(byte[] data)
             {
                 if (startLexeme.Value.ToString() == "StandardEncoding")
                 {
-                    return new StandardEncoding();
+                    return SingleByteEncoding.Standard;
                 }
                 else
                 {

diff --git a/src/PdfToSvg/Fonts/Type1Font.cs b/src/PdfToSvg/Fonts/Type1Font.cs
@@ -54,7 +54,7 @@ private Dictionary<string, uint> GetPostGlyphIndexLookup()
         protected override IEnumerable<CharInfo> GetChars()
         {
             // ISO 32000-2 section 9.6.5.2
-            var encoding = pdfFontEncoding ?? openTypeFontEncoding ?? new StandardEncoding();
+            var encoding = pdfFontEncoding ?? openTypeFontEncoding ?? SingleByteEncoding.Standard;
 
             var postGlyphIndexes = GetPostGlyphIndexLookup();
             var cmap = openTypeFont?.CMaps.OrderByPriority().FirstOrDefault();

diff --git a/src/PdfToSvg/Fonts/Type3Font.cs b/src/PdfToSvg/Fonts/Type3Font.cs
@@ -90,7 +90,7 @@ private void PopulateOpenType(CancellationToken cancellationToken)
             var transform = FontMatrix * Matrix.Scale(TargetEmSize, TargetEmSize);
 
             var charProcs = fontDict.GetDictionaryOrEmpty(Names.CharProcs);
-            var encoding = pdfFontEncoding ?? new StandardEncoding();
+            var encoding = pdfFontEncoding ?? SingleByteEncoding.Standard;
 
             // Handle glyphs
             var glyphs = new List<CompactFontGlyph>();

diff --git a/src/PdfToSvg/Security/KeyAlgorithms.cs b/src/PdfToSvg/Security/KeyAlgorithms.cs
@@ -43,7 +43,7 @@ private static void PadPassword(byte[] output, string password)
 #endif
 
             // Convert codepage encoding to PDFDocEncoding
-            var encoding = new PdfDocEncoding();
+            var encoding = SingleByteEncoding.PdfDoc;
             var decodeCharCount = Math.Min(PaddedPasswordLength, password.Length);
             var passwordLength = encoding.GetBytes(password, 0, decodeCharCount, output, 0);
 

diff --git a/tests/PdfToSvg.Tests/Encodings/CustomEncodingTests.cs b/tests/PdfToSvg.Tests/Encodings/CustomEncodingTests.cs
@@ -26,7 +26,7 @@ public void DecodeText()
                     39, new PdfName("Ebreve"),
                     128, new PdfName("Ncaron"), new PdfName("Wcircumflex"),
                 } },
-            }, new StandardEncoding());
+            }, SingleByteEncoding.Standard);
 
             var str = decoder.GetString(new byte[] { 39, 128, 129, 198 });
             var bytes = decoder.GetBytes("ĔŇŴÆ");

diff --git a/tests/PdfToSvg.Tests/Encodings/EncodingTests.cs b/tests/PdfToSvg.Tests/Encodings/EncodingTests.cs
@@ -25,7 +25,7 @@ public void WinAnsi()
                 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#¤%&/()=?" +
                 "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ";
 
-            var winAnsi = new WinAnsiEncoding();
+            var winAnsi = SingleByteEncoding.WinAnsi;
             var net1252 = Encoding.GetEncoding(1252);
 
             Assert.AreEqual(source, net1252.GetString(winAnsi.GetBytes(source)));
@@ -41,7 +41,7 @@ public void MacRoman()
                 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#¤%&/()=?" +
                 "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÑÒÓÔÕÖØÙÚÛÜßàáâãäåæçèéêëìíîïñòóôõö÷øùúûüÿ";
 
-            var macRoman = new MacRomanEncoding();
+            var macRoman = SingleByteEncoding.MacRoman;
 
             Assert.AreEqual(source, macRoman.GetString(macRoman.GetBytes(source)));
             Assert.AreEqual("ÊËÎ", macRoman.GetString(new byte[] { 0xe6, 0xe8, 0xeb }));
@@ -53,7 +53,7 @@ public void Standard()
         {
             var source = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#¤%&/()=?";
 
-            var standard = new StandardEncoding();
+            var standard = SingleByteEncoding.Standard;
 
             Assert.AreEqual(source, standard.GetString(standard.GetBytes(source)));
             Assert.AreEqual("ÆŁæ", standard.GetString(new byte[] { 0xe1, 0xe8, 0xf1 }));
@@ -67,7 +67,7 @@ public void PdfDocEncoding()
                 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#¤%&/()=?" +
                 "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÑÒÓÔÕÖ×ØÙÚÛÜßàáâãäåæçèéêëìíîïñòóôõö÷øùúûüÿ";
 
-            var pdfDoc = new PdfDocEncoding();
+            var pdfDoc = SingleByteEncoding.PdfDoc;
 
             Assert.AreEqual(source, pdfDoc.GetString(pdfDoc.GetBytes(source)));
             Assert.AreEqual("œž¥", pdfDoc.GetString(new byte[] { 0x9c, 0x9e, 0xa5 }));