1 files changed, 129 insertions, 0 deletions
diff --git a/core/fpdfapi/parser/cpdf_cross_ref_table.cpp b/core/fpdfapi/parser/cpdf_cross_ref_table.cpp
new file mode 100644
index 0000000000..770c483dca
--- /dev/null
+++ b/core/fpdfapi/parser/cpdf_cross_ref_table.cpp
@@ -0,0 +1,129 @@
+// Copyright 2018 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/fpdfapi/parser/cpdf_cross_ref_table.h"
+
+#include <utility>
+
+#include "core/fpdfapi/parser/cpdf_dictionary.h"
+
+CPDF_CrossRefTable::CPDF_CrossRefTable() = default;
+
+CPDF_CrossRefTable::CPDF_CrossRefTable(std::unique_ptr<CPDF_Dictionary> trailer)
+    : trailer_(std::move(trailer)) {}
+
+CPDF_CrossRefTable::~CPDF_CrossRefTable() = default;
+
+void CPDF_CrossRefTable::AddCompressed(uint32_t obj_num,
+                                       uint32_t archive_obj_num) {
+  auto& info = objects_info_[obj_num];
+  if (info.gennum > 0)
+    return;
+
+  if (info.type == ObjectType::kObjStream)
+    return;
+
+  info.type = ObjectType::kCompressed;
+  info.archive_obj_num = archive_obj_num;
+  info.gennum = 0;
+
+  objects_info_[archive_obj_num].type = ObjectType::kObjStream;
+}
+
+void CPDF_CrossRefTable::AddNormal(uint32_t obj_num,
+                                   uint16_t gen_num,
+                                   FX_FILESIZE pos) {
+  auto& info = objects_info_[obj_num];
+  if (info.gennum > gen_num)
+    return;
+
+  if (info.type == ObjectType::kCompressed && gen_num == 0)
+    return;
+
+  if (info.type != ObjectType::kObjStream)
+    info.type = ObjectType::kNormal;
+
+  info.gennum = gen_num;
+  info.pos = pos;
+}
+
+void CPDF_CrossRefTable::SetFree(uint32_t obj_num) {
+  auto& info = objects_info_[obj_num];
+  info.type = ObjectType::kFree;
+  info.gennum = 0xFFFF;
+  info.pos = 0;
+}
+
+void CPDF_CrossRefTable::SetTrailer(std::unique_ptr<CPDF_Dictionary> trailer) {
+  trailer_ = std::move(trailer);
+}
+
+const CPDF_CrossRefTable::ObjectInfo* CPDF_CrossRefTable::GetObjectInfo(
+    uint32_t obj_num) const {
+  const auto it = objects_info_.find(obj_num);
+  return it != objects_info_.end() ? &it->second : nullptr;
+}
+
+void CPDF_CrossRefTable::Update(
+    std::unique_ptr<CPDF_CrossRefTable> new_cross_ref) {
+  UpdateInfo(std::move(new_cross_ref->objects_info_));
+  UpdateTrailer(std::move(new_cross_ref->trailer_));
+}
+
+void CPDF_CrossRefTable::ShrinkObjectMap(uint32_t objnum) {
+  if (objnum == 0) {
+    objects_info_.clear();
+    return;
+  }
+
+  objects_info_.erase(objects_info_.lower_bound(objnum), objects_info_.end());
+
+  if (!pdfium::ContainsKey(objects_info_, objnum - 1))
+    objects_info_[objnum - 1].pos = 0;
+}
+
+void CPDF_CrossRefTable::UpdateInfo(
+    std::map<uint32_t, ObjectInfo>&& new_objects_info) {
+  auto cur_it = objects_info_.begin();
+  auto new_it = new_objects_info.begin();
+  while (cur_it != objects_info_.end() && new_it != new_objects_info.end()) {
+    if (cur_it->first == new_it->first) {
+      if (cur_it->second.type == ObjectType::kObjStream &&
+          new_it->second.type == ObjectType::kNormal) {
+        new_it->second.type = ObjectType::kObjStream;
+      }
+      ++cur_it;
+      ++new_it;
+    } else if (cur_it->first < new_it->first) {
+      new_objects_info.insert(new_it, *cur_it);
+      ++cur_it;
+    } else {
+      new_it = new_objects_info.lower_bound(cur_it->first);
+    }
+  }
+  for (; cur_it != objects_info_.end(); ++cur_it) {
+    new_objects_info.insert(new_objects_info.end(), *cur_it);
+  }
+  objects_info_ = std::move(new_objects_info);
+}
+
+void CPDF_CrossRefTable::UpdateTrailer(
+    std::unique_ptr<CPDF_Dictionary> new_trailer) {
+  if (!new_trailer)
+    return;
+
+  if (!trailer_) {
+    trailer_ = std::move(new_trailer);
+    return;
+  }
+
+  new_trailer->SetFor("XRefStm", trailer_->RemoveFor("XRefStm"));
+  new_trailer->SetFor("Prev", trailer_->RemoveFor("Prev"));
+
+  for (auto it = new_trailer->begin(); it != new_trailer->end();) {
+    const ByteString key = it->first;
+    ++it;
+    trailer_->SetFor(key, new_trailer->RemoveFor(key));
+  }
+}