Merge branch 'master' of https://github.com/UglyToad/PdfPig

src/UglyToad.PdfPig/Content/IPageFactory.cs

@@ -6,7 +6,5 @@
     {
         Page Create(int number, DictionaryToken dictionary, PageTreeMembers pageTreeMembers, 
             bool isLenientParsing);
-
-        void LoadResources(DictionaryToken dictionary, bool isLenientParsing);
     }
 }

src/UglyToad.PdfPig/Content/IResourceStore.cs

@@ -7,6 +7,12 @@
     {
         void LoadResourceDictionary(DictionaryToken resourceDictionary, bool isLenientParsing);
 
+        /// <summary>
+        /// Remove any named resources and associated state for the last resource dictionary loaded.
+        /// Does not affect the cached resources, just the labels associated with them.
+        /// </summary>
+        void UnloadResourceDictionary();
+
         IFont GetFont(NameToken name);
 
         StreamToken GetXObject(NameToken name);

src/UglyToad.PdfPig/Content/PageTreeMembers.cs

@@ -1,5 +1,8 @@
 namespace UglyToad.PdfPig.Content
 {
+    using System.Collections.Generic;
+    using Tokens;
+
     /// <summary>
     /// Contains the values inherited from the Page Tree for this page.
     /// </summary>
@@ -13,5 +16,7 @@
         public MediaBox MediaBox { get; set; }
 
         public int Rotation { get; set; }
+
+        public Queue<DictionaryToken> ParentResources { get; } = new Queue<DictionaryToken>();
     }
 }

src/UglyToad.PdfPig/Content/Pages.cs

@@ -50,7 +50,10 @@
             {
                 currentNode = pageStack.Pop();
 
-                pageFactory.LoadResources(currentNode.NodeDictionary, isLenientParsing);
+                if (currentNode.NodeDictionary.TryGet(NameToken.Resources, pdfScanner, out DictionaryToken resourcesDictionary))
+                {
+                    pageTreeMembers.ParentResources.Enqueue(resourcesDictionary);
+                }
                 
                 if (currentNode.NodeDictionary.TryGet(NameToken.MediaBox, pdfScanner, out ArrayToken mediaBox))
                 {

src/UglyToad.PdfPig/Content/ResourceStore.cs

@@ -7,6 +7,7 @@
     using Parser.Parts;
     using Tokenization.Scanner;
     using Tokens;
+    using Util;
 
     internal class ResourceStore : IResourceStore
     {
@@ -14,7 +15,7 @@
         private readonly IFontFactory fontFactory;
 
         private readonly Dictionary<IndirectReference, IFont> loadedFonts = new Dictionary<IndirectReference, IFont>();
-        private readonly Dictionary<NameToken, IndirectReference> currentResourceState = new Dictionary<NameToken, IndirectReference>();
+        private readonly StackDictionary<NameToken, IndirectReference> currentResourceState = new StackDictionary<NameToken, IndirectReference>();
 
         private readonly Dictionary<NameToken, DictionaryToken> extendedGraphicsStates = new Dictionary<NameToken, DictionaryToken>();
 
@@ -28,6 +29,8 @@
 
         public void LoadResourceDictionary(DictionaryToken resourceDictionary, bool isLenientParsing)
         {
+            currentResourceState.Push();
+
             if (resourceDictionary.TryGet(NameToken.Font, out var fontBase))
             {
                 var fontDictionary = DirectObjectFinder.Get<DictionaryToken>(fontBase, scanner);
@@ -95,6 +98,11 @@
             }
         }
 
+        public void UnloadResourceDictionary()
+        {
+            currentResourceState.Pop();
+        }
+
         private void LoadFontDictionary(DictionaryToken fontDictionary, bool isLenientParsing)
         {
             foreach (var pair in fontDictionary.Data)

src/UglyToad.PdfPig/Encryption/EncryptionHandler.cs

@@ -392,7 +392,9 @@
                                 continue;
                             }
 
-                            if (keyValuePair.Value is StringToken || keyValuePair.Value is ArrayToken || keyValuePair.Value is DictionaryToken)
+                            if (keyValuePair.Value is StringToken || keyValuePair.Value is ArrayToken 
+                                                                  || keyValuePair.Value is DictionaryToken
+                                                                  || keyValuePair.Value is HexToken)
                             {
                                 var inner = DecryptInternal(reference, keyValuePair.Value);
                                 dictionary = dictionary.With(keyValuePair.Key, inner);

src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs

@@ -336,7 +336,8 @@
              * 5. Restore the saved graphics state, as if by invoking the Q operator.
              */
 
-            if (formStream.StreamDictionary.TryGet<DictionaryToken>(NameToken.Resources, pdfScanner, out var formResources))
+            var hasResources = formStream.StreamDictionary.TryGet<DictionaryToken>(NameToken.Resources, pdfScanner, out var formResources);
+            if (hasResources)
             {
                 resourceStore.LoadResourceDictionary(formResources, isLenientParsing);
             }
@@ -368,6 +369,11 @@
 
             // 5. Restore saved state.
             PopState();
+
+            if (hasResources)
+            {
+                resourceStore.UnloadResourceDictionary();
+            }
         }
 
         public void BeginSubpath()

src/UglyToad.PdfPig/Parser/PageFactory.cs

@@ -58,9 +58,23 @@
             MediaBox mediaBox = GetMediaBox(number, dictionary, pageTreeMembers, isLenientParsing);
             CropBox cropBox = GetCropBox(dictionary, pageTreeMembers, mediaBox, isLenientParsing);
 
-            UserSpaceUnit userSpaceUnit = GetUserSpaceUnits(dictionary);
+            var stackDepth = 0;
 
-            LoadResources(dictionary, isLenientParsing);
+            while (pageTreeMembers.ParentResources.Count > 0)
+            {
+                var resource = pageTreeMembers.ParentResources.Dequeue();
+
+                resourceStore.LoadResourceDictionary(resource, isLenientParsing);
+                stackDepth++;
+            }
+
+            if (dictionary.TryGet(NameToken.Resources, pdfScanner, out DictionaryToken resources))
+            {
+                resourceStore.LoadResourceDictionary(resources, isLenientParsing);
+                stackDepth++;
+            }
+            
+            UserSpaceUnit userSpaceUnit = GetUserSpaceUnits(dictionary);
 
             PageContent content = default(PageContent);
 
@@ -114,6 +128,11 @@
 
             var page = new Page(number, dictionary, mediaBox, cropBox, rotation, content, new AnnotationProvider(pdfScanner, dictionary, isLenientParsing));
 
+            for (var i = 0; i < stackDepth; i++)
+            {
+                resourceStore.UnloadResourceDictionary();
+            }
+
             return page;
         }
 
@@ -201,17 +220,5 @@
 
             return mediaBox;
         }
-
-        public void LoadResources(DictionaryToken dictionary, bool isLenientParsing)
-        {
-            if (!dictionary.TryGet(NameToken.Resources, out var token))
-            {
-                return;
-            }
-
-            var resources = DirectObjectFinder.Get<DictionaryToken>(token, pdfScanner);
-
-            resourceStore.LoadResourceDictionary(resources, isLenientParsing);
-        }
     }
 }

src/UglyToad.PdfPig/Util/StackDictionary.cs

@@ -0,0 +1,68 @@
+// ReSharper disable InconsistentNaming
+namespace UglyToad.PdfPig.Util
+{
+    using System;
+    using System.Collections.Generic;
+
+    internal class StackDictionary<K, V>
+    {
+        private readonly List<Dictionary<K, V>> values = new List<Dictionary<K, V>>();
+
+        public V this[K key]
+        {
+            get
+            {
+                if (TryGetValue(key, out var result))
+                {
+                    return result;
+                }
+
+                throw new KeyNotFoundException($"No item with key {key} in stack.");
+            }
+            set
+            {
+                if (values.Count == 0)
+                {
+                    throw new InvalidOperationException($"Cannot set item in empty stack, call {nameof(Push)} before use.");
+                }
+
+                values[values.Count - 1][key] = value;
+            }
+        }
+
+        public bool TryGetValue(K key, out V result)
+        {
+            if (values.Count == 0)
+            {
+                throw new InvalidOperationException($"Cannot get item from empty stack, call {nameof(Push)} before use.");
+            }
+
+            for (var i = values.Count - 1; i >= 0; i--)
+            {
+                if (values[i].TryGetValue(key, out result))
+                {
+                    return true;
+                }
+            }
+
+            result = default(V);
+
+            return false;
+        }
+
+        public void Push()
+        {
+            values.Add(new Dictionary<K, V>());
+        }
+
+        public void Pop()
+        {
+            if (values.Count == 0)
+            {
+                throw new InvalidOperationException("Cannot pop empty stacked dictionary.");
+            }
+
+            values.RemoveAt(values.Count - 1);
+        }
+    }
+}