Seal and update IFilters to return ReadOnlyMemory<byte> (#843)

* Avoid ToArray() in memoryFactory * Seal and update IFilters to return ReadOnlyMemory<byte> * Fix filter tests * Seal and update IFilters to return ReadOnlyMemory<byte>
UglyToad · Jun 8, 2024 · affc1ed · affc1ed
1 parent 65a18b2
commit affc1ed
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Showing 18 changed files with 41 additions and 49 deletions.
diff --git a/src/UglyToad.PdfPig.Tests/Filters/Ascii85FilterTests.cs b/src/UglyToad.PdfPig.Tests/Filters/Ascii85FilterTests.cs
@@ -22,7 +22,7 @@ public void DecodesWikipediaExample()
 
             var result = filter.Decode(bytes, dictionary, 0);
 
-            var text = Encoding.ASCII.GetString(result);
+            var text = Encoding.ASCII.GetString(result.ToArray());
 
             Assert.Equal("Man is distinguished, not only by his reason, but by this singular passion from other animals, which is a lust of the mind, " +
                          "that by a perseverance of delight in the continued and indefatigable generation of knowledge, " +
@@ -37,7 +37,7 @@ public void ReplacesZWithEmptyBytes()
 
             var result = filter.Decode(bytes, dictionary, 1);
 
-            var text = Encoding.ASCII.GetString(result);
+            var text = Encoding.ASCII.GetString(result.ToArray());
 
             Assert.Equal("Man \0\0\0\0is d", text);
         }
@@ -104,7 +104,7 @@ public void DecodesEncodedPdfContent()
 
             var result = filter.Decode(Encoding.ASCII.GetBytes(input), dictionary, 0);
 
-            var text = Encoding.ASCII.GetString(result);
+            var text = Encoding.ASCII.GetString(result.ToArray());
 
             Assert.Equal(PdfContent.Replace("\r\n", "\n"), text);
         }
@@ -124,7 +124,7 @@ public void DecodesEncodedPdfContentMissingEndOfDataSymbol()
 
             var result = filter.Decode(Encoding.ASCII.GetBytes(input), dictionary, 0);
 
-            var text = Encoding.ASCII.GetString(result);
+            var text = Encoding.ASCII.GetString(result.ToArray());
 
             Assert.Equal(PdfContent.Replace("\r\n", "\n"), text);
         }

diff --git a/src/UglyToad.PdfPig.Tests/Filters/AsciiHexDecodeFilterTests.cs b/src/UglyToad.PdfPig.Tests/Filters/AsciiHexDecodeFilterTests.cs
@@ -18,7 +18,7 @@ public void DecodesEncodedTextProperly()
 
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
-            var decodedText = Encoding.ASCII.GetString(decoded);
+            var decodedText = Encoding.ASCII.GetString(decoded.ToArray());
 
             Assert.Equal(text, decodedText);
         }
@@ -33,7 +33,7 @@ public void DecodesEncodedTextWithBracesProperly()
 
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
-            var decodedText = Encoding.ASCII.GetString(decoded);
+            var decodedText = Encoding.ASCII.GetString(decoded.ToArray());
 
             Assert.Equal(text, decodedText);
         }
@@ -49,7 +49,7 @@ public void DecodesEncodedTextWithWhitespaceProperly()
 
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
-            var decodedText = Encoding.ASCII.GetString(decoded);
+            var decodedText = Encoding.ASCII.GetString(decoded.ToArray());
 
             Assert.Equal(text, decodedText);
         }
@@ -63,7 +63,7 @@ public void DecodesEncodedTextLowercaseProperly()
 
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
-            var decodedText = Encoding.ASCII.GetString(decoded);
+            var decodedText = Encoding.ASCII.GetString(decoded.ToArray());
 
             Assert.Equal(text, decodedText);
         }
@@ -88,7 +88,7 @@ public void SubstitutesZeroForLastByte()
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
 #pragma warning disable SYSLIB0001
-            var decodedText = Encoding.UTF7.GetString(decoded);
+            var decodedText = Encoding.UTF7.GetString(decoded.ToArray());
 #pragma warning restore SYSLIB0001
 
             Assert.Equal("®P", decodedText);
@@ -103,7 +103,7 @@ public void DecodesEncodedTextStoppingAtLastBrace()
 
             var decoded = new AsciiHexDecodeFilter().Decode(input, dictionary, 1);
 
-            var decodedText = Encoding.ASCII.GetString(decoded);
+            var decodedText = Encoding.ASCII.GetString(decoded.ToArray());
 
             Assert.Equal(text, decodedText);
         }

diff --git a/src/UglyToad.PdfPig.Tests/Filters/CcittFaxDecodeFilterTests.cs b/src/UglyToad.PdfPig.Tests/Filters/CcittFaxDecodeFilterTests.cs
@@ -32,7 +32,7 @@ public void CanDecodeCCittFaxCompressedImageData()
 
             var expectedBytes = ImageHelpers.LoadFileBytes("ccittfax-decoded.bin");
             var decodedBytes = filter.Decode(encodedBytes, new DictionaryToken(dictionary), 0);
-            Assert.Equal(expectedBytes, decodedBytes);
+            Assert.Equal(expectedBytes, decodedBytes.ToArray());
         }
     }
 }
diff --git a/src/UglyToad.PdfPig.Tests/Filters/FlateFilterTests.cs b/src/UglyToad.PdfPig.Tests/Filters/FlateFilterTests.cs
@@ -18,7 +18,7 @@ public void EncodeAndDecodePreservesInput()
                 inputStream.Seek(0, SeekOrigin.Begin);
                 var result = filter.Encode(inputStream, parameters, 0);
                 var decoded = filter.Decode(result, parameters, 0);
-                Assert.Equal(input, decoded);
+                Assert.Equal(input, decoded.ToArray());
             }
         }
     }

diff --git a/src/UglyToad.PdfPig.Tests/Filters/RunLengthFilterTests.cs b/src/UglyToad.PdfPig.Tests/Filters/RunLengthFilterTests.cs
@@ -35,7 +35,7 @@ public void CanDecodeRunLengthEncodedData()
                 10, 19
             };
 
-            Assert.Equal(expectedResult, decoded);
+            Assert.Equal(expectedResult, decoded.ToArray());
         }
 
         [Fact]
@@ -61,7 +61,7 @@ public void StopsAtEndOfDataByte()
                 128, 50
             };
 
-            Assert.Equal(expectedResult, decoded);
+            Assert.Equal(expectedResult, decoded.ToArray());
         }
     }
 }
diff --git a/src/UglyToad.PdfPig.Tests/Integration/PdfParserTests.cs b/src/UglyToad.PdfPig.Tests/Integration/PdfParserTests.cs
@@ -96,14 +96,14 @@ public void CanDecompressPngEncodedFlateStream()
             });
 
             var filter = new FlateFilter();
-            var filtered = filter.Decode(streamBytes, dictionary, 0);
+            var filtered = filter.Decode(streamBytes, dictionary, 0).ToArray();
 
             var expected =
                 "1 0 15 0 1 0 216 0 1 2 160 0 1 2 210 0 1 3 84 0 1 4 46 0 1 7 165 0 1 70 229 0 1 72 84 0 1 96 235 0 1 98 18 0 2 0 12 0 2 0 12 1 2 0 12 2 2 0 12 3 2 0 12 4 2 0 12 5 2 0 12 6 2 0 12 7 2 0 12 8"
                 .Split(' ')
                 .Select(byte.Parse).ToArray();
 
-            Assert.Equal(filtered, expected);
+            Assert.Equal(expected, filtered);
         }
 
         /// <summary>

diff --git a/src/UglyToad.PdfPig/Content/InlineImage.cs b/src/UglyToad.PdfPig/Content/InlineImage.cs
@@ -93,14 +93,14 @@ internal InlineImage(PdfRectangle bounds, int widthInSamples, int heightInSample
 
             memoryFactory = supportsFilters ? new Lazy<ReadOnlyMemory<byte>>(() =>
             {
-                var b = rawMemory.Span;
+                var b = RawMemory;
                 for (var i = 0; i < filters.Count; i++)
                 {
                     var filter = filters[i];
-                    b = filter.Decode(b, streamDictionary, i);
+                    b = filter.Decode(b.Span, streamDictionary, i);
                 }
 
-                return b.ToArray();
+                return b;
             }) : null;
         }
 

diff --git a/src/UglyToad.PdfPig/Filters/Ascii85Filter.cs b/src/UglyToad.PdfPig/Filters/Ascii85Filter.cs
@@ -1,15 +1,14 @@
 namespace UglyToad.PdfPig.Filters
 {
     using System;
-    using System.Collections.Generic;
     using Core;
     using Tokens;
 
     /// <inheritdoc />
     /// <summary>
     /// ASCII 85 (Base85) is a binary to text encoding using 5 ASCII characters per 4 bytes of data.
     /// </summary>
-    internal class Ascii85Filter : IFilter
+    internal sealed class Ascii85Filter : IFilter
     {
         private const byte EmptyBlock = (byte)'z';
         private const byte Offset = (byte)'!';
@@ -29,7 +28,7 @@ internal class Ascii85Filter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             var asciiBuffer = new byte[5];
 
@@ -98,8 +97,7 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
                 WriteData(asciiBuffer, index, writer);
             }
 
-            return writer.WrittenSpan.ToArray();
-
+            return writer.WrittenMemory;
         }
 
         private static void WriteData(Span<byte> ascii, int index, ArrayPoolBufferWriter<byte> writer)

diff --git a/src/UglyToad.PdfPig/Filters/AsciiHexDecodeFilter.cs b/src/UglyToad.PdfPig/Filters/AsciiHexDecodeFilter.cs
@@ -29,7 +29,7 @@ internal sealed class AsciiHexDecodeFilter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             Span<byte> pair = stackalloc byte[2];
             var index = 0;
@@ -69,7 +69,7 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
                 WriteHexToByte(pair, writer);
             }
 
-            return writer.WrittenSpan.ToArray();
+            return writer.WrittenMemory;
         }
 
         private static void WriteHexToByte(ReadOnlySpan<byte> hexBytes, ArrayPoolBufferWriter<byte> writer)

diff --git a/src/UglyToad.PdfPig/Filters/CcittFaxDecodeFilter.cs b/src/UglyToad.PdfPig/Filters/CcittFaxDecodeFilter.cs
@@ -16,7 +16,7 @@ internal sealed class CcittFaxDecodeFilter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             var decodeParms = DecodeParameterResolver.GetFilterParameters(streamDictionary, filterIndex);
 

diff --git a/src/UglyToad.PdfPig/Filters/DctDecodeFilter.cs b/src/UglyToad.PdfPig/Filters/DctDecodeFilter.cs
@@ -3,13 +3,13 @@
     using System;
     using Tokens;
 
-    internal class DctDecodeFilter : IFilter
+    internal sealed class DctDecodeFilter : IFilter
     {
         /// <inheritdoc />
         public bool IsSupported { get; } = false;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             throw new NotSupportedException("The DST (Discrete Cosine Transform) Filter indicates data is encoded in JPEG format. " +
                                             "This filter is not currently supported but the raw data can be supplied to JPEG supporting libraries.");

diff --git a/src/UglyToad.PdfPig/Filters/FlateFilter.cs b/src/UglyToad.PdfPig/Filters/FlateFilter.cs
@@ -32,7 +32,7 @@ internal sealed class FlateFilter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             var parameters = DecodeParameterResolver.GetFilterParameters(streamDictionary, filterIndex);
 
@@ -52,9 +52,7 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
                 var bitsPerComponent = parameters.GetIntOrDefault(NameToken.BitsPerComponent, DefaultBitsPerComponent);
                 var columns = parameters.GetIntOrDefault(NameToken.Columns, DefaultColumns);
 
-                var result = PngPredictor.Decode(decompressed, predictor, colors, bitsPerComponent, columns);
-
-                return result;
+                return PngPredictor.Decode(decompressed, predictor, colors, bitsPerComponent, columns);
             }
             catch
             {
@@ -64,7 +62,7 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
             return bytes;
         }
 
-        private byte[] Decompress(byte[] input)
+        private static byte[] Decompress(byte[] input)
         {
             using (var memoryStream = new MemoryStream(input))
             using (var output = new MemoryStream())

diff --git a/src/UglyToad.PdfPig/Filters/IFilter.cs b/src/UglyToad.PdfPig/Filters/IFilter.cs
@@ -20,6 +20,6 @@ public interface IFilter
         /// <param name="streamDictionary">The dictionary of the <see cref="StreamToken"/> (or other dictionary types, e.g. inline images) containing these bytes.</param>
         /// <param name="filterIndex">The position of this filter in the pipeline used to encode data.</param>
         /// <returns>The decoded bytes.</returns>
-        byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex);
+        ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex);
     }
 }
diff --git a/src/UglyToad.PdfPig/Filters/Jbig2DecodeFilter.cs b/src/UglyToad.PdfPig/Filters/Jbig2DecodeFilter.cs
@@ -9,7 +9,7 @@ internal sealed class Jbig2DecodeFilter : IFilter
         public bool IsSupported { get; } = false;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             throw new NotSupportedException("The JBIG2 Filter for monochrome image data is not currently supported. " +
                                             "Try accessing the raw compressed data directly.");

diff --git a/src/UglyToad.PdfPig/Filters/JpxDecodeFilter.cs b/src/UglyToad.PdfPig/Filters/JpxDecodeFilter.cs
@@ -3,13 +3,13 @@
     using System;
     using Tokens;
 
-    internal class JpxDecodeFilter : IFilter
+    internal sealed class JpxDecodeFilter : IFilter
     {
         /// <inheritdoc />
         public bool IsSupported { get; } = false;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             throw new NotSupportedException("The JPX Filter (JPEG2000) for image data is not currently supported. " +
                                             "Try accessing the raw compressed data directly.");

diff --git a/src/UglyToad.PdfPig/Filters/LzwFilter.cs b/src/UglyToad.PdfPig/Filters/LzwFilter.cs
@@ -29,7 +29,7 @@ internal sealed class LzwFilter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             var parameters = DecodeParameterResolver.GetFilterParameters(streamDictionary, filterIndex);
 
@@ -45,14 +45,10 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
                 var bitsPerComponent = parameters.GetIntOrDefault(NameToken.BitsPerComponent, DefaultBitsPerComponent);
                 var columns = parameters.GetIntOrDefault(NameToken.Columns, DefaultColumns);
 
-                var result = PngPredictor.Decode(decompressed, predictor, colors, bitsPerComponent, columns);
-
-                return result;
+                return PngPredictor.Decode(decompressed, predictor, colors, bitsPerComponent, columns);
             }
 
-            var data = Decode(input, earlyChange == 1);
-
-            return data;
+            return Decode(input, earlyChange == 1);
         }
 
         private static byte[] Decode(ReadOnlySpan<byte> input, bool isEarlyChange)

diff --git a/src/UglyToad.PdfPig/Filters/RunLengthFilter.cs b/src/UglyToad.PdfPig/Filters/RunLengthFilter.cs
@@ -17,7 +17,7 @@ internal sealed class RunLengthFilter : IFilter
         public bool IsSupported { get; } = true;
 
         /// <inheritdoc />
-        public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
+        public ReadOnlyMemory<byte> Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary, int filterIndex)
         {
             using var output = new ArrayPoolBufferWriter<byte>(input.Length);
 
@@ -63,7 +63,7 @@ public byte[] Decode(ReadOnlySpan<byte> input, DictionaryToken streamDictionary,
                 }
             }
 
-            return output.WrittenSpan.ToArray();
+            return output.WrittenMemory;
         }
     }
 }
diff --git a/src/UglyToad.PdfPig/Polyfills/EncodingExtensions.cs b/src/UglyToad.PdfPig/Polyfills/EncodingExtensions.cs
@@ -1,10 +1,10 @@
-#if NETFRAMEWORK || NETSTANDARD2_0
+#if !NET
 
 namespace System.Text;
 
 internal static class EncodingExtensions
 {
-    public static string GetString(this Encoding encoding, ReadOnlySpan<byte> bytes)
+    internal static string GetString(this Encoding encoding, ReadOnlySpan<byte> bytes)
     {
         if (bytes.IsEmpty)
         {