fix bug where cross reference stream subsections were skipped

a single cross-reference stream may contain multiple disjoint runs of object numbers, previously we only took the first now we load all objects.

adds indexer to array token for ease-of-use.

adds page number and bounds information to all form fields.

src/UglyToad.PdfPig.Tests/Integration/AcroFormsBasicFieldsTests.cs

@@ -39,19 +39,20 @@
             using (var document = PdfDocument.Open(GetFilename(), ParsingOptions.LenientParsingOff))
             {
                 var form = document.GetForm();
-                Assert.Equal(16, form.Fields.Count);
+                Assert.Equal(18, form.Fields.Count);
             }
         }
 
-        [Fact]
+        //[Fact]
-        public void GetsEmptyFormFields()
+        //public void GetFormFieldsByPage()
-        {
+        //{
-            using (var document = PdfDocument.Open(GetFilename(), ParsingOptions.LenientParsingOff))
+        //    using (var document = PdfDocument.Open(GetFilename(), ParsingOptions.LenientParsingOff))
-            {
+        //    {
-                var form = document.GetForm();
+        //        var form = document.GetForm();
-                var annots = document.GetPage(1).ExperimentalAccess.GetAnnotations().ToList();
+        //        var fields = form.GetFieldsForPage(1).ToList();
-                Assert.Equal(16, form.Fields.Count);
+        //        var page = document.GetPage(1).ExperimentalAccess.GetAnnotations().ToList();
-            }
+        //        Assert.Equal(16, fields.Count);
-        }
+        //    }
+        //}
     }
 }

src/UglyToad.PdfPig/AcroForms/AcroForm.cs

@@ -48,6 +48,25 @@
             Fields = fields ?? throw new ArgumentNullException(nameof(fields));
         }
 
+        /// <summary>
+        /// Get the set of fields which appear on the given page number.
+        /// </summary>
+        public IEnumerable<AcroFieldBase> GetFieldsForPage(int pageNumber)
+        {
+            if (pageNumber <= 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(pageNumber), $"Page number starts at 1, instead got {pageNumber}.");
+            }
+
+            foreach (var field in Fields)
+            {
+                if (field.Value.PageNumber == pageNumber)
+                {
+                    yield return field.Value;
+                }
+            }
+        }
+
         /// <inheritdoc />
         public override string ToString()
         {

src/UglyToad.PdfPig/AcroForms/AcroFormFactory.cs

@@ -7,6 +7,7 @@
     using Exceptions;
     using Fields;
     using Filters;
+    using Geometry;
     using Parser.Parts;
     using Tokenization.Scanner;
     using Tokens;
@@ -38,7 +39,7 @@
             {
                 return null;
             }
-
+            
             var signatureFlags = (SignatureFlags)0;
             if (acroDictionary.TryGetOptionalTokenDirect(NameToken.SigFlags, tokenScanner, out NumericToken signatureToken))
             {
@@ -91,7 +92,7 @@
 
                 var fieldDictionary = DirectObjectFinder.Get<DictionaryToken>(fieldToken, tokenScanner);
 
-                var field = GetAcroField(fieldDictionary);
+                var field = GetAcroField(fieldDictionary, catalog);
 
                 fields[fieldReferenceToken.Data] = field;
             }
@@ -99,7 +100,7 @@
             return new AcroForm(acroDictionary, signatureFlags, needAppearances, fields);
         }
 
-        private AcroFieldBase GetAcroField(DictionaryToken fieldDictionary)
+        private AcroFieldBase GetAcroField(DictionaryToken fieldDictionary, Catalog catalog)
         {
             fieldDictionary.TryGet(NameToken.Ft, out NameToken fieldType);
             fieldDictionary.TryGet(NameToken.Ff, out NumericToken fieldFlagsToken);
@@ -134,6 +135,17 @@
             fieldDictionary.TryGet(NameToken.Parent, out IndirectReferenceToken parentReferenceToken);
             var information = new AcroFieldCommonInformation(parentReferenceToken?.Data, partialFieldName, alternateFieldName, mappingName);
 
+            int? pageNumber = null;
+            if (fieldDictionary.TryGet(NameToken.P, tokenScanner, out IndirectReferenceToken pageReference))
+            {
+                pageNumber = catalog.GetPageByReference(pageReference.Data)?.PageNumber;
+            }
+
+            PdfRectangle? bounds = null;
+            if (fieldDictionary.TryGet(NameToken.Rect, tokenScanner, out ArrayToken rectArray) && rectArray.Length == 4)
+            {
+                bounds = rectArray.ToRectangle();
+            }
 
             var fieldFlags = (uint) (fieldFlagsToken?.Long ?? 0);
 
@@ -143,7 +155,7 @@
                 var children = new List<AcroFieldBase>();
                 foreach (var kid in kids)
                 {
-                    var kidField = GetAcroField(kid);
+                    var kidField = GetAcroField(kid, catalog);
                     children.Add(kidField);
                 }
 
@@ -155,12 +167,16 @@
 
                 if (buttonFlags.HasFlag(AcroButtonFieldFlags.Radio))
                 {
-                    var field = new AcroRadioButtonsField(fieldDictionary, fieldType, buttonFlags, information);
+                    var field = new AcroRadioButtonsField(fieldDictionary, fieldType, buttonFlags, information, 
+                        pageNumber, 
+                        bounds);
                     result = field;
                 }
                 else if (buttonFlags.HasFlag(AcroButtonFieldFlags.PushButton))
                 {
-                    var field = new AcroPushButtonField(fieldDictionary, fieldType, buttonFlags, information);
+                    var field = new AcroPushButtonField(fieldDictionary, fieldType, buttonFlags, information,
+                        pageNumber,
+                        bounds);
                     result = field;
                 }
                 else
@@ -175,25 +191,30 @@
                         isChecked = !string.Equals(valueToken.Data, NameToken.Off, StringComparison.OrdinalIgnoreCase);
                     }
 
-                    var field = new AcroCheckboxField(fieldDictionary, fieldType, buttonFlags, 
+                    var field = new AcroCheckboxField(fieldDictionary, fieldType, buttonFlags, information, 
-                        information, 
                         valueToken,
-                        isChecked);
+                        isChecked,
+                        pageNumber,
+                        bounds);
 
                     result = field;
                 }
             }
             else if (fieldType == NameToken.Tx)
             {
-                result = GetTextField(fieldDictionary, fieldType, fieldFlags, information);
+                result = GetTextField(fieldDictionary, fieldType, fieldFlags, information, pageNumber, bounds);
             }
             else if (fieldType == NameToken.Ch)
             {
-                result = GetChoiceField(fieldDictionary, fieldType, fieldFlags, information);
+                result = GetChoiceField(fieldDictionary, fieldType, fieldFlags, information, 
+                    pageNumber,
+                    bounds);
             }
             else if (fieldType == NameToken.Sig)
             {
-                var field = new AcroSignatureField(fieldDictionary, fieldType, fieldFlags, information);
+                var field = new AcroSignatureField(fieldDictionary, fieldType, fieldFlags, information,
+                    pageNumber,
+                    bounds);
                 result = field;
             }
             else
@@ -204,7 +225,10 @@
             return result;
         }
 
-        private AcroFieldBase GetTextField(DictionaryToken fieldDictionary, NameToken fieldType, uint fieldFlags, AcroFieldCommonInformation information)
+        private AcroFieldBase GetTextField(DictionaryToken fieldDictionary, NameToken fieldType, uint fieldFlags, 
+            AcroFieldCommonInformation information, 
+            int? pageNumber,
+            PdfRectangle? bounds)
         {
             var textFlags = (AcroTextFieldFlags)fieldFlags;
 
@@ -231,12 +255,20 @@
                 maxLength = maxLenToken.Int;
             }
 
-            var field = new AcroTextField(fieldDictionary, fieldType, textFlags, information, textValue, maxLength);
+            var field = new AcroTextField(fieldDictionary, fieldType, textFlags, information, 
+                textValue, 
+                maxLength,
+                pageNumber,
+                bounds);
 
             return field;
         }
 
-        private AcroFieldBase GetChoiceField(DictionaryToken fieldDictionary, NameToken fieldType, uint fieldFlags, AcroFieldCommonInformation information)
+        private AcroFieldBase GetChoiceField(DictionaryToken fieldDictionary, NameToken fieldType,
+            uint fieldFlags, 
+            AcroFieldCommonInformation information,
+            int? pageNumber,
+            PdfRectangle? bounds)
         {
             var selectedOptions = EmptyArray<string>.Instance;
             if (fieldDictionary.TryGet(NameToken.V, out var valueToken))
@@ -348,7 +380,12 @@
             
             if (choiceFlags.HasFlag(AcroChoiceFieldFlags.Combo))
             {
-                var field = new AcroComboBoxField(fieldDictionary, fieldType, choiceFlags, information, options, selectedOptions, selectedIndices);
+                var field = new AcroComboBoxField(fieldDictionary, fieldType, choiceFlags, information,
+                    options,
+                    selectedOptions, 
+                    selectedIndices,
+                    pageNumber,
+                    bounds);
                 return field;
             }
 
@@ -358,7 +395,13 @@
                 topIndex = topIndexToken.Int;
             }
 
-            return new AcroListBoxField(fieldDictionary, fieldType, choiceFlags, information, options, selectedOptions, selectedIndices, topIndex);
+            return new AcroListBoxField(fieldDictionary, fieldType, choiceFlags, information, 
+                options,
+                selectedOptions, 
+                selectedIndices,
+                topIndex,
+                pageNumber,
+                bounds);
         }
 
         private static bool IsChoiceSelected(IReadOnlyList<string> selectedOptionNames, IReadOnlyList<int> selectedOptionIndices, int index, string name)

src/UglyToad.PdfPig/AcroForms/Fields/AcroCheckboxField.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
+    using Geometry;
     using Tokens;
 
     /// <inheritdoc />
@@ -29,8 +30,11 @@
         /// </summary>
         public AcroCheckboxField(DictionaryToken dictionary, string fieldType, AcroButtonFieldFlags fieldFlags,
             AcroFieldCommonInformation information, NameToken currentValue,
-            bool isChecked) :
+            bool isChecked,
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.Checkbox, information)
+            int? pageNumber,
+            PdfRectangle? bounds) :
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.Checkbox, information,
+                pageNumber, bounds)
         {
             Flags = fieldFlags;
             CurrentValue = currentValue;

src/UglyToad.PdfPig/AcroForms/Fields/AcroComboBoxField.cs

@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using Geometry;
     using Tokens;
     using Util.JetBrains.Annotations;
 
@@ -46,11 +47,17 @@
         /// <param name="options">The options in this field.</param>
         /// <param name="selectedOptionIndices">The indices of the selected options where there are multiple with the same name.</param>
         /// <param name="selectedOptions">The names of the selected options.</param>
+        /// <param name="pageNumber">The number of the page this field appears on.</param>
+        /// <param name="bounds">The location of this field on the page.</param>
         public AcroComboBoxField(DictionaryToken dictionary, string fieldType, AcroChoiceFieldFlags fieldFlags,
             AcroFieldCommonInformation information, IReadOnlyList<AcroChoiceOption> options, 
             IReadOnlyList<string> selectedOptions, 
-            IReadOnlyList<int> selectedOptionIndices) :
+            IReadOnlyList<int> selectedOptionIndices,
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.ComboBox, information)
+            int? pageNumber,
+            PdfRectangle? bounds) :
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.ComboBox, information,
+                pageNumber,
+                bounds)
         {
             Flags = fieldFlags;
             Options = options ?? throw new ArgumentNullException(nameof(options));

src/UglyToad.PdfPig/AcroForms/Fields/AcroFieldBase.cs

@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
     using System;
+    using Geometry;
     using Tokens;
     using Util.JetBrains.Annotations;
 
@@ -37,6 +38,16 @@
         [NotNull]
         public AcroFieldCommonInformation Information { get; }
 
+        /// <summary>
+        /// The page number of the page containing this form field if known.
+        /// </summary>
+        public int? PageNumber { get; }
+
+        /// <summary>
+        /// The placement rectangle of this form field on the page given by <see cref="PageNumber"/> if known.
+        /// </summary>
+        public PdfRectangle? Bounds { get; }
+
         /// <summary>
         /// Create a new <see cref="AcroFieldBase"/>.
         /// </summary>
@@ -45,16 +56,22 @@
         /// <param name="fieldFlags">The flags specifying behaviour for this field.</param>
         /// <param name="fieldType">The type of this field.</param>
         /// <param name="information">Additional information for this field.</param>
+        /// <param name="pageNumber">The number of the page this field appears on.</param>
+        /// <param name="bounds">The location of this field on the page.</param>
         protected AcroFieldBase(DictionaryToken dictionary, string rawFieldType,
             uint fieldFlags, 
             AcroFieldType fieldType,
-            AcroFieldCommonInformation information)
+            AcroFieldCommonInformation information,
+            int? pageNumber,
+            PdfRectangle? bounds)
         {
             Dictionary = dictionary ?? throw new ArgumentNullException(nameof(dictionary));
             RawFieldType = rawFieldType ?? throw new ArgumentNullException(nameof(rawFieldType));
             FieldFlags = fieldFlags;
             FieldType = fieldType;
             Information = information ?? new AcroFieldCommonInformation(null, null, null, null);
+            PageNumber = pageNumber;
+            Bounds = bounds;
         }
 
         /// <inheritdoc />

src/UglyToad.PdfPig/AcroForms/Fields/AcroListBoxField.cs

@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using Geometry;
     using Tokens;
     using Util.JetBrains.Annotations;
 
@@ -56,12 +57,16 @@
         /// <param name="selectedOptionIndices">The indices of the selected options where there are multiple with the same name.</param>
         /// <param name="topIndex">The first visible option index.</param>
         /// <param name="selectedOptions">The names of the selected options.</param>
+        /// <param name="pageNumber">The number of the page this field appears on.</param>
+        /// <param name="bounds">The location of this field on the page.</param>
         public AcroListBoxField(DictionaryToken dictionary, string fieldType, AcroChoiceFieldFlags fieldFlags,
             AcroFieldCommonInformation information, IReadOnlyList<AcroChoiceOption> options,
             IReadOnlyList<string> selectedOptions, 
             IReadOnlyList<int> selectedOptionIndices,
-            int? topIndex) : 
+            int? topIndex,
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.ListBox, information)
+            int? pageNumber,
+            PdfRectangle? bounds) : 
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.ListBox, information, pageNumber, bounds)
         {
             Flags = fieldFlags;
             Options = options ?? throw new ArgumentNullException(nameof(options));

src/UglyToad.PdfPig/AcroForms/Fields/AcroNonTerminalField.cs

@@ -21,7 +21,8 @@
         /// </summary>
         internal AcroNonTerminalField(DictionaryToken dictionary, string fieldType, uint fieldFlags, AcroFieldCommonInformation information,
             IReadOnlyList<AcroFieldBase> children) : 
-            base(dictionary, fieldType, fieldFlags, AcroFieldType.NonTerminal, information)
+            base(dictionary, fieldType, fieldFlags, AcroFieldType.NonTerminal, information,
+                null, null)
         {
             Children = children ?? throw new ArgumentNullException(nameof(children));
         }

src/UglyToad.PdfPig/AcroForms/Fields/AcroPushButtonField.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
+    using Geometry;
     using Tokens;
 
     /// <inheritdoc />
@@ -17,9 +18,12 @@
         /// <summary>
         /// Create a new <see cref="AcroPushButtonField"/>.
         /// </summary>
-        public AcroPushButtonField(DictionaryToken dictionary, string fieldType, AcroButtonFieldFlags fieldFlags, 
+        public AcroPushButtonField(DictionaryToken dictionary, string fieldType, 
-            AcroFieldCommonInformation information) : 
+            AcroButtonFieldFlags fieldFlags, 
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.PushButton, information)
+            AcroFieldCommonInformation information,
+            int? pageNumber,
+            PdfRectangle? bounds) : 
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.PushButton, information, pageNumber, bounds)
         {
             Flags = fieldFlags;
         }

src/UglyToad.PdfPig/AcroForms/Fields/AcroRadioButtonsField.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
+    using Geometry;
     using Tokens;
 
     /// <inheritdoc />
@@ -18,8 +19,10 @@
         /// Create a new <see cref="AcroRadioButtonsField"/>.
         /// </summary>
         public AcroRadioButtonsField(DictionaryToken dictionary, string fieldType, AcroButtonFieldFlags fieldFlags, 
-            AcroFieldCommonInformation information) : 
+            AcroFieldCommonInformation information,
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.RadioButton, information)
+            int? pageNumber,
+            PdfRectangle? bounds) : 
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.RadioButton, information, pageNumber, bounds)
         {
             Flags = fieldFlags;
         }

src/UglyToad.PdfPig/AcroForms/Fields/AcroSignatureField.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
+    using Geometry;
     using Tokens;
 
     /// <inheritdoc />
@@ -12,8 +13,11 @@
         /// <summary>
         /// Create a new <see cref="T:UglyToad.PdfPig.AcroForms.Fields.AcroSignatureField" />.
         /// </summary>
-        public AcroSignatureField(DictionaryToken dictionary, string fieldType, uint fieldFlags, AcroFieldCommonInformation information) : 
+        public AcroSignatureField(DictionaryToken dictionary, string fieldType, uint fieldFlags, 
-            base(dictionary, fieldType, fieldFlags, AcroFieldType.Signature, information)
+            AcroFieldCommonInformation information,
+            int? pageNumber,
+            PdfRectangle? bounds) : 
+            base(dictionary, fieldType, fieldFlags, AcroFieldType.Signature, information, pageNumber, bounds)
         {
         }
     }

src/UglyToad.PdfPig/AcroForms/Fields/AcroTextField.cs

@@ -1,5 +1,6 @@
 namespace UglyToad.PdfPig.AcroForms.Fields
 {
+    using Geometry;
     using Tokens;
 
     /// <inheritdoc />
@@ -45,9 +46,15 @@
         /// <param name="information">Additional information for this field.</param>
         /// <param name="value">The text value.</param>
         /// <param name="maxLength">The maximum length.</param>
+        /// <param name="pageNumber">The number of the page this field appears on.</param>
+        /// <param name="bounds">The location of this field on the page.</param>
         public AcroTextField(DictionaryToken dictionary, string fieldType, AcroTextFieldFlags fieldFlags,
-            AcroFieldCommonInformation information, string value, int? maxLength) : 
+            AcroFieldCommonInformation information, 
-            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.Text, information)
+            string value,
+            int? maxLength,
+            int? pageNumber,
+            PdfRectangle? bounds) : 
+            base(dictionary, fieldType, (uint)fieldFlags, AcroFieldType.Text, information, pageNumber, bounds)
         {
             Flags = fieldFlags;
             Value = value;

src/UglyToad.PdfPig/Content/Catalog.cs

@@ -78,5 +78,18 @@
 
             return node;
         }
+
+        internal PageTreeNode GetPageByReference(IndirectReference reference)
+        {
+            foreach (var page in pagesByNumber)
+            {
+                if (page.Value.Reference.Equals(reference))
+                {
+                    return page.Value;
+                }
+            }
+
+            return null;
+        }
     }
 }

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

@@ -92,13 +92,13 @@
                     break;
                 case 1:
                     // Non object stream entries.
-                    int offset = 0;
+                    var offset = 0;
-                    for (int i = 0; i < fieldSizes.Field2Size; i++)
+                    for (var i = 0; i < fieldSizes.Field2Size; i++)
                     {
                         offset += (lineBuffer[i + fieldSizes.Field1Size] & 0x00ff) << ((fieldSizes.Field2Size - i - 1) * 8);
                     }
-                    int genNum = 0;
+                    var genNum = 0;
-                    for (int i = 0; i < fieldSizes.Field3Size; i++)
+                    for (var i = 0; i < fieldSizes.Field3Size; i++)
                     {
                         genNum += (lineBuffer[i + fieldSizes.Field1Size + fieldSizes.Field2Size] & 0x00ff) << ((fieldSizes.Field3Size - i - 1) * 8);
                     }
@@ -122,8 +122,8 @@
                      * table but add object stream number with minus sign in order to
                      * distinguish from file offsets
                      */
-                    int objstmObjNr = 0;
+                    var objstmObjNr = 0;
-                    for (int i = 0; i < fieldSizes.Field2Size; i++)
+                    for (var i = 0; i < fieldSizes.Field2Size; i++)
                     {
                         objstmObjNr += (lineBuffer[i + fieldSizes.Field1Size] & 0x00ff) << ((fieldSizes.Field2Size - i - 1) * 8);
                     }
@@ -134,32 +134,37 @@
             }
         }
 
-        private static List<long> GetObjectNumbers(DictionaryToken dictionary)
+        private static IEnumerable<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))
             {
                 throw new PdfDocumentFormatException($"The stream dictionary must contain a numeric size value: {dictionary}.");
             }
-
+            
-            var indexArray = new[] { 0, sizeNumeric.Int };
+            var objNums = new List<long>();
 
             if (dictionary.TryGet(NameToken.Index, out var indexToken) && indexToken is ArrayToken indexArrayToken)
             {
-                indexArray = new[]
+                // An array containing a pair of integers for each subsection in this section. 
+                // Pair[0] is the first object number in the subsection; Pair[1] is the number of entries in the subsection.
+                for (var i = 0; i < indexArrayToken.Length; i += 2)
                 {
-                    indexArrayToken.GetNumeric(0).Int,
+                    var firstObjectNumber = indexArrayToken.GetNumeric(i).Int;
-                    indexArrayToken.GetNumeric(1).Int
+                    var size = indexArrayToken.GetNumeric(i + 1).Int;
-                };
+
+                    for (var j = 0; j < size; j++)
+                    {
+                        objNums.Add(firstObjectNumber + j);
+                    }
+                }
             }
-
+            else
-            List<long> objNums = new List<long>();
-            
-            var firstObjectNumber = indexArray[0];
-            var size = indexArray[1];
-
-            for (var i = 0; i < size; i++)
             {
-                objNums.Add(firstObjectNumber + i);
+                for (var i = 0; i < sizeNumeric.Int; i++)
+                {
+                    objNums.Add(i);
+                }
             }
 
             return objNums;

src/UglyToad.PdfPig/Tokens/ArrayToken.cs

@@ -23,6 +23,11 @@
         /// </summary>
         public int Length { get; }
 
+        /// <summary>
+        /// Indexer into <see cref="Data"/> for convenience.
+        /// </summary>
+        public IToken this[int i] => Data[i];
+
         /// <summary>
         /// Create a new <see cref="ArrayToken"/>.
         /// </summary>