Implement CPDF_CrossRefTable

Change-Id: I5ac61ab323adb5eec2de8660064fff95ee877b5e
Reviewed-on: https://pdfium-review.googlesource.com/35432
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Art Snake <art-snake@yandex-team.ru>

1 files changed, 68 insertions, 0 deletions

diff --git a/core/fpdfapi/parser/cpdf_cross_ref_table.h b/core/fpdfapi/parser/cpdf_cross_ref_table.h
new file mode 100644
index 0000000000..ade1b336b2
--- /dev/null
+++ b/core/fpdfapi/parser/cpdf_cross_ref_table.h
@@ -0,0 +1,68 @@
+// 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.
+
+#ifndef CORE_FPDFAPI_PARSER_CPDF_CROSS_REF_TABLE_H_
+#define CORE_FPDFAPI_PARSER_CPDF_CROSS_REF_TABLE_H_
+
+#include <map>
+#include <memory>
+
+#include "core/fxcrt/fx_system.h"
+
+class CPDF_Dictionary;
+
+class CPDF_CrossRefTable {
+ public:
+  enum class ObjectType : uint8_t {
+    kFree = 0x00,
+    kNormal = 0x01,
+    kNotCompressed = kNormal,
+    kCompressed = 0x02,
+    kObjStream = 0xFF,
+    kNull = kObjStream,
+  };
+
+  struct ObjectInfo {
+    ObjectInfo() : pos(0), type(ObjectType::kFree), gennum(0) {}
+    // if type is ObjectType::kCompressed the archive_obj_num should be used.
+    // if type is ObjectType::kNotCompressed the pos should be used.
+    // In other cases its are unused.
+    union {
+      FX_FILESIZE pos;
+      uint32_t archive_obj_num;
+    };
+    ObjectType type;
+    uint16_t gennum;
+  };
+
+  CPDF_CrossRefTable();
+  explicit CPDF_CrossRefTable(std::unique_ptr<CPDF_Dictionary> trailer);
+  ~CPDF_CrossRefTable();
+
+  void AddCompressed(uint32_t obj_num, uint32_t archive_obj_num);
+  void AddNormal(uint32_t obj_num, uint16_t gen_num, FX_FILESIZE pos);
+  void SetFree(uint32_t obj_num);
+
+  const CPDF_Dictionary* trailer() const { return trailer_.get(); }
+  void SetTrailer(std::unique_ptr<CPDF_Dictionary> trailer);
+
+  const ObjectInfo* GetObjectInfo(uint32_t obj_num) const;
+
+  const std::map<uint32_t, ObjectInfo>& objects_info() const {
+    return objects_info_;
+  }
+
+  void Update(std::unique_ptr<CPDF_CrossRefTable> new_cross_ref);
+
+  void ShrinkObjectMap(uint32_t objnum);
+
+ private:
+  void UpdateInfo(std::map<uint32_t, ObjectInfo>&& new_objects_info);
+  void UpdateTrailer(std::unique_ptr<CPDF_Dictionary> new_trailer);
+
+  std::unique_ptr<CPDF_Dictionary> trailer_;
+  std::map<uint32_t, ObjectInfo> objects_info_;
+};
+
+#endif  // CORE_FPDFAPI_PARSER_CPDF_CROSS_REF_TABLE_H_