make tokenizer classes internal and change the file header to use a scanner rather than the pdfbox type reader

src/UglyToad.Pdf.Tests/Parser/Parts/FileHeaderParserTests.cs

@@ -0,0 +1,135 @@
+namespace UglyToad.Pdf.Tests.Parser.Parts
+{
+    using System;
+    using Exceptions;
+    using Pdf.Parser.Parts;
+    using Xunit;
+
+    public class FileHeaderParserTests
+    {
+        private readonly FileHeaderParser parser = new FileHeaderParser(new TestingLog());
+
+        [Fact]
+        public void NullScannerThrows()
+        {
+            Action action = () => parser.Parse(null, false);
+
+            Assert.Throws<ArgumentNullException>(action);
+        }
+
+        [Theory]
+        [InlineData("PDF-1.0")]
+        [InlineData("PDF-1.1")]
+        [InlineData("PDF-1.7")]
+        [InlineData("PDF-1.9")]
+        [InlineData("FDF-1.0")]
+        [InlineData("FDF-1.9")]
+        public void ReadsConformingHeader(string format)
+        {
+            var input = $"%{format}\nany garbage";
+
+            var scanner = StringBytesTestConverter.Scanner(input);
+
+            var result = parser.Parse(scanner, false);
+
+            Assert.Equal(format, result.VersionString);
+        }
+
+        [Fact]
+        public void ReadsHeaderWithBlankSpaceBefore()
+        {
+            const string input = @"     
+
+%PDF-1.2";
+
+            var scanner = StringBytesTestConverter.Scanner(input);
+
+            var result = parser.Parse(scanner, false);
+
+            Assert.Equal(1.2m, result.Version);
+        }
+
+        [Fact]
+        public void EmptyInputThrows()
+        {
+            var scanner = StringBytesTestConverter.Scanner(string.Empty);
+            
+            Action action = () => parser.Parse(scanner, false);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+
+        [Fact]
+        public void HeaderPrecededByJunkNonLenientThrows()
+        {
+            var scanner = StringBytesTestConverter.Scanner(@"one    
+    %PDF-1.2");
+
+            Action action = () => parser.Parse(scanner, false);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+
+        [Fact]
+        public void HeaderPrecededByJunkLenientReads()
+        {
+            var scanner = StringBytesTestConverter.Scanner(@"one    
+    %PDF-1.7");
+
+            var result = parser.Parse(scanner, true);
+
+            Assert.Equal(1.7m, result.Version);
+        }
+
+        [Fact]
+        public void HeaderPrecededByTooMuchJunkThrows()
+        {
+            var scanner = StringBytesTestConverter.Scanner(@"one two
+three %PDF-1.6");
+
+            Action action = () => parser.Parse(scanner, true);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+
+        [Fact]
+        public void JunkThenEndThrows()
+        {
+            var scanner = StringBytesTestConverter.Scanner(@"one two");
+
+            Action action = () => parser.Parse(scanner, true);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+
+        [Fact]
+        public void VersionFormatInvalidNotLenientThrows()
+        {
+            var scanner = StringBytesTestConverter.Scanner("%Pdeef-1.69");
+
+            Action action = () => parser.Parse(scanner, false);
+
+            Assert.Throws<PdfDocumentFormatException>(action);
+        }
+
+        [Fact]
+        public void VersionFormatInvalidLenientDefaults1Point4()
+        {
+            var scanner = StringBytesTestConverter.Scanner("%Pdeef-1.69");
+
+            var result = parser.Parse(scanner, true);
+
+            Assert.Equal(1.4m, result.Version);
+        }
+
+        [Fact]
+        public void ParsingResetsPosition()
+        {
+            var scanner = StringBytesTestConverter.Scanner(@"%FDF-1.6");
+
+            parser.Parse(scanner, false);
+
+            Assert.Equal(0, scanner.CurrentPosition);
+        }
+    }
+}

src/UglyToad.Pdf.Tests/StringBytesTestConverter.cs

@@ -2,6 +2,8 @@
 {
     using System.Text;
     using IO;
+    using Pdf.Tokenization.Scanner;
+    using Pdf.Util;
 
     public static class StringBytesTestConverter
     {
@@ -29,5 +31,12 @@
 
             public IInputBytes Bytes { get; set; }
         }
+
+        internal static CoreTokenScanner Scanner(string s)
+        {
+            var result = new CoreTokenScanner(new ByteArrayInputBytes(OtherEncodings.StringAsLatin1Bytes(s)));
+
+            return result;
+        }
     }
 }

src/UglyToad.Pdf/IO/ByteArrayInputBytes.cs

@@ -9,20 +9,21 @@
         public ByteArrayInputBytes(IReadOnlyList<byte> bytes)
         {
             this.bytes = bytes;
-            CurrentOffset = -1;
+            currentOffset = -1;
         }
         
-        public int CurrentOffset { get; private set; }
+        private int currentOffset;
+        public int CurrentOffset => currentOffset + 1;
 
         public bool MoveNext()
         {
-            if (CurrentOffset == bytes.Count - 1)
+            if (currentOffset == bytes.Count - 1)
             {
                 return false;
             }
 
-            CurrentOffset++;
-            CurrentByte = bytes[CurrentOffset];
+            currentOffset++;
+            CurrentByte = bytes[currentOffset];
             return true;
         }
 
@@ -30,23 +31,23 @@
 
         public byte? Peek()
         {
-            if (CurrentOffset == bytes.Count - 1)
+            if (currentOffset == bytes.Count - 1)
             {
                 return null;
             }
 
-            return bytes[CurrentOffset + 1];
+            return bytes[currentOffset + 1];
         }
 
         public bool IsAtEnd()
         {
-            return CurrentOffset == bytes.Count - 1;
+            return currentOffset == bytes.Count - 1;
         }
 
         public void Seek(long position)
         {
-            CurrentOffset = (int)position - 1;
-            CurrentByte = CurrentOffset < 0 ? (byte)0 : bytes[CurrentOffset];
+            currentOffset = (int)position - 1;
+            CurrentByte = currentOffset < 0 ? (byte)0 : bytes[currentOffset];
         }
     }
 }

src/UglyToad.Pdf/Parser/Parts/FileHeaderParser.cs

@@ -2,9 +2,10 @@
 {
     using System;
     using System.Text.RegularExpressions;
-    using IO;
+    using Exceptions;
     using Logging;
-    using Util;
+    using Tokenization.Scanner;
+    using Tokenization.Tokens;
     using Util.JetBrains.Annotations;
 
     /// <summary>
@@ -21,14 +22,12 @@
     /// %PDF–1.5
     /// %PDF–1.6
     /// %PDF–1.7
+    /// This parser allows versions up to 1.9.
     /// For versions equal or greater to PDF 1.4, the optional Version entry in the document’s catalog dictionary should be used instead of the header version.
     /// </remarks>
-    public class FileHeaderParser
+    internal class FileHeaderParser
     {
-        private const string PdfHeader = "%PDF-";
-        private const string FdfHeader = "%FDF-";
-        private const string PdfDefaultVersion = "1.4";
-        private const string FdfDefaultVersion = "1.0";
+        private static readonly Regex VersionRegex = new Regex(@"[FP]DF-(?<version>1.\d)", RegexOptions.IgnoreCase);
 
         private readonly ILog log;
 
@@ -38,115 +37,59 @@
         }
 
         [NotNull]
-        public HeaderVersion ReadHeader([NotNull]IRandomAccessRead reader, bool isLenientParsing)
+        public HeaderVersion Parse([NotNull]ISeekableTokenScanner scanner, bool isLenientParsing)
         {
-            if (reader == null)
+            if (scanner == null)
             {
-                throw new ArgumentNullException(nameof(reader));
+                throw new ArgumentNullException(nameof(scanner));
             }
 
-            if (TryFindHeader(PdfHeader, PdfDefaultVersion, reader, isLenientParsing, out var version))
+            // Read the first token
+            if (!scanner.MoveNext())
             {
-                return version;
+                throw new PdfDocumentFormatException($"Could not read the first token in the document at position {scanner.CurrentPosition}.");
             }
 
-            if (TryFindHeader(FdfHeader, FdfDefaultVersion, reader, isLenientParsing, out version))
+            var comment = scanner.CurrentToken as CommentToken;
+
+            var junkSkip = isLenientParsing ? 2 : 0;
+            var attempts = 0;
+            while (comment == null)
             {
-                return version;
+                if (attempts == junkSkip)
+                {
+                    throw new PdfDocumentFormatException("Could not find the version header comment at the start of the document.");
                 }
 
-            throw new FormatException("The pdf or fdf document did not seem to contain a version header.");
+                if (!scanner.MoveNext())
+                {
+                    throw new PdfDocumentFormatException("Could not find the version header comment at the start of the document.");
                 }
 
-        private bool TryFindHeader(string marker, string defaultVersion, IRandomAccessRead reader, bool isLenientParsing, out HeaderVersion version)
-        {
-            version = null;
+                comment = scanner.CurrentToken as CommentToken;
 
-            // Read the first line
-            var currentLine = ReadHelper.ReadLine(reader);
-
-            if (!currentLine.Contains(marker))
-            {
-                // Move to the next line
-                currentLine = ReadHelper.ReadLine(reader);
-
-                while (!currentLine.Contains(marker))
-                {
-                    var startsWithDigit = currentLine.Length > 0 && char.IsDigit(currentLine[0]);
-                    // if a line starts with a digit, it has to be the first one with data in it
-                    if (startsWithDigit)
-                    {
-                        break;
+                attempts++;
             }
             
-                    currentLine = ReadHelper.ReadLine(reader);
-                }
-            }
+            var match = VersionRegex.Match(comment.Data);
 
-            if (!currentLine.Contains(marker))
-            {
-                reader.ReturnToBeginning();
-                return false;
-            }
-
-            var headerStartIndex = currentLine.IndexOf(marker, StringComparison.OrdinalIgnoreCase);
-
-            if (headerStartIndex > 0)
-            {
-                //trim off any leading characters
-                currentLine = currentLine.Substring(headerStartIndex);
-            }
-
-            var regex = new Regex($"{marker}\\d.\\d");
-            if (currentLine.StartsWith(marker) && !regex.IsMatch(currentLine))
-            {
-                if (currentLine.Length < marker.Length + 3)
-                {
-                    // No version number at all, set to 1.4 as default
-                    currentLine = marker + defaultVersion;
-                    //LOG.debug("No version found, set to " + defaultVersion + " as default.");
-                }
-                else
-                {
-                    var headerGarbage = currentLine.Substring(marker.Length + 3) + "\n";
-
-                    currentLine = currentLine.Substring(0, marker.Length + 3);
-
-                    reader.Rewind(OtherEncodings.StringAsLatin1Bytes(headerGarbage).Length);
-                }
-            }
-
-            decimal headerVersion = -1;
-            try
-            {
-                var headerParts = currentLine.Split('-');
-
-                if (headerParts.Length == 2)
-                {
-                    headerVersion = decimal.Parse(headerParts[1]);
-                }
-            }
-            catch (FormatException ex)
-            {
-                log?.Debug("Can't parse the header version: " + currentLine, ex);
-            }
-
-            if (headerVersion < 0)
+            if (!match.Success || !decimal.TryParse(match.Groups["version"].Value, out decimal version))
             {
                 if (isLenientParsing)
                 {
-                    headerVersion = 1.7m;
-                }
-                else
-                {
-                    throw new InvalidOperationException("Error getting header version: " + currentLine);
-                }
+                    log.Warn($"Did not find a version header of the correct format, defaulting to 1.4 since lenient. Header was: {comment.Data}.");
+
+                    return new HeaderVersion(1.4m, "PDF-1.4");
                 }
 
-            reader.ReturnToBeginning();
-            version = new HeaderVersion(headerVersion, currentLine);
+                throw new PdfDocumentFormatException($"The comment which should have provided the version was in the wrong format: {comment.Data}.");
+            }
 
-            return true;
+            scanner.Seek(0);
+
+            var result = new HeaderVersion(version, comment.Data);
+
+            return result;
         }
     }
 }

src/UglyToad.Pdf/Parser/Parts/HeaderVersion.cs

@@ -1,6 +1,6 @@
 namespace UglyToad.Pdf.Parser.Parts
 {
-    public class HeaderVersion
+    internal class HeaderVersion
     {
         public decimal Version { get; }
 
@@ -11,5 +11,10 @@
             Version = version;
             VersionString = versionString;
         }
+
+        public override string ToString()
+        {
+            return $"Version: {VersionString}";
+        }
     }
 }

src/UglyToad.Pdf/Parser/PdfDocumentFactory.cs

@@ -16,6 +16,7 @@
     using Logging;
     using Parts;
     using Parts.CrossReference;
+    using Tokenization.Scanner;
     using Util;
 
     internal static class PdfDocumentFactory
@@ -28,7 +29,9 @@
 
             var reader = new RandomAccessBuffer(fileBytes);
 
-            var document = OpenDocument(reader, container, isLenientParsing);
+            var tokenScanner = new CoreTokenScanner(new ByteArrayInputBytes(fileBytes));
+
+            var document = OpenDocument(reader,tokenScanner, container,  isLenientParsing);
 
             return document;
         }
@@ -43,11 +46,11 @@
             return Open(File.ReadAllBytes(filename), options);
         }
 
-        private static PdfDocument OpenDocument(IRandomAccessRead reader, IContainer container, bool isLenientParsing)
+        private static PdfDocument OpenDocument(IRandomAccessRead reader, ISeekableTokenScanner scanner, IContainer container, bool isLenientParsing)
         {
             var log = container.Get<ILog>();
 
-            var version = container.Get<FileHeaderParser>().ReadHeader(reader, isLenientParsing);
+            var version = container.Get<FileHeaderParser>().Parse(scanner, isLenientParsing);
 
             var crossReferenceOffset = container.Get<FileTrailerParser>().GetXrefOffset(reader, isLenientParsing);
 

src/UglyToad.Pdf/PdfDocument.cs

@@ -32,6 +32,11 @@
         [NotNull]
         public DocumentInformation Information { get; }
 
+        /// <summary>
+        /// The version number of the PDF specification which this file conforms to, for example 1.4.
+        /// </summary>
+        public decimal Version => version.Version;
+
         /// <summary>
         /// Get the number of pages in this document.
         /// </summary>

src/UglyToad.Pdf/Tokenization/ArrayTokenizer.cs

@@ -5,7 +5,7 @@
     using Scanner;
     using Tokens;
 
-    public class ArrayTokenizer : ITokenizer
+    internal class ArrayTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = false;
 

src/UglyToad.Pdf/Tokenization/CommentTokenizer.cs

@@ -5,7 +5,7 @@
     using Parser.Parts;
     using Tokens;
 
-    public class CommentTokenizer : ITokenizer
+    internal class CommentTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = true;
 

src/UglyToad.Pdf/Tokenization/DictionaryTokenizer.cs

@@ -8,7 +8,7 @@
     using Tokens;
     using Util.JetBrains.Annotations;
 
-    public class DictionaryTokenizer : ITokenizer
+    internal class DictionaryTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = false;
 

src/UglyToad.Pdf/Tokenization/HexTokenizer.cs

@@ -5,7 +5,7 @@
     using Parser.Parts;
     using Tokens;
 
-    public class HexTokenizer : ITokenizer
+    internal class HexTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = false;
 

src/UglyToad.Pdf/Tokenization/NameTokenizer.cs

@@ -7,7 +7,7 @@
     using Parser.Parts;
     using Tokens;
 
-    public class NameTokenizer : ITokenizer
+    internal class NameTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = true;
 

src/UglyToad.Pdf/Tokenization/NumericTokenizer.cs

@@ -6,7 +6,7 @@
     using IO;
     using Tokens;
 
-    public class NumericTokenizer : ITokenizer
+    internal class NumericTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = true;
 

src/UglyToad.Pdf/Tokenization/PlainTokenizer.cs

@@ -5,7 +5,7 @@
     using Parser.Parts;
     using Tokens;
 
-    public class PlainTokenizer : ITokenizer
+    internal class PlainTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = true;
 

src/UglyToad.Pdf/Tokenization/Scanner/CoreTokenScanner.cs

@@ -7,14 +7,7 @@
     using Tokenization;
     using Tokens;
 
-    internal enum ScannerScope
-    {
-        None,
-        Array,
-        Dictionary
-    }
-
-    public class CoreTokenScanner : ITokenScanner
+    internal class CoreTokenScanner : ISeekableTokenScanner
     {
         private static readonly HexTokenizer HexTokenizer = new HexTokenizer();
         private static readonly StringTokenizer StringTokenizer = new StringTokenizer();
@@ -48,6 +41,13 @@
             return false;
         }
 
+        public void Seek(long position)
+        {
+            inputBytes.Seek(position);
+        }
+
+        public long CurrentPosition => inputBytes.CurrentOffset;
+
         private bool hasBytePreRead;
 
         internal CoreTokenScanner(IInputBytes inputBytes, ScannerScope scope = ScannerScope.None)

src/UglyToad.Pdf/Tokenization/Scanner/ITokenScanner.cs

@@ -2,7 +2,7 @@
 {
     using Tokens;
 
-    public interface ITokenScanner
+    internal interface ITokenScanner
     {
         bool MoveNext();
 
@@ -10,4 +10,11 @@
 
         bool TryReadToken<T>(out T token) where T : class, IToken;
     }
+
+    internal interface ISeekableTokenScanner : ITokenScanner
+    {
+        void Seek(long position);
+
+        long CurrentPosition { get; }
+    }
 }

src/UglyToad.Pdf/Tokenization/Scanner/ScannerScope.cs

@@ -0,0 +1,9 @@
+namespace UglyToad.Pdf.Tokenization.Scanner
+{
+    internal enum ScannerScope
+    {
+        None,
+        Array,
+        Dictionary
+    }
+}

src/UglyToad.Pdf/Tokenization/StringTokenizer.cs

@@ -6,7 +6,7 @@
     using Tokens;
     using Util;
 
-    public class StringTokenizer : ITokenizer
+    internal class StringTokenizer : ITokenizer
     {
         public bool ReadsNextByte { get; } = false;