Unify some code

core/fpdfapi/parser/cpdf_linearized.cpp

+// Copyright 2016 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.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "core/fpdfapi/parser/cpdf_linearized.h"
+
+#include "core/fpdfapi/parser/cpdf_dictionary.h"

[Lei Zhang, 2016/11/01 00:29:53]

nit: alphabetical order

[snake, 2016/11/01 14:39:24]

Done.

+#include "core/fpdfapi/parser/cpdf_array.h"
+
+// static
+std::unique_ptr<CPDF_Linearized> CPDF_Linearized::CreateForObject(
+    std::unique_ptr<CPDF_Object, ReleaseDeleter<CPDF_Object>> pObj) {
+  if (!pObj)
+    return std::unique_ptr<CPDF_Linearized>();
+  CPDF_Dictionary* pDict = pObj->GetDict();
+  if (!pDict || !pDict->GetObjectFor("Linearized"))
+    return std::unique_ptr<CPDF_Linearized>();
+  return std::unique_ptr<CPDF_Linearized>(new CPDF_Linearized(pDict));

[Lei Zhang, 2016/11/01 00:29:53]

We have MakeUnique() in PDFium too.

[snake, 2016/11/01 14:39:24]

I can not use pdfium::MakeUnique in this case, because the constructor of 
CPDF_Linearized is private.

[Lei Zhang, 2016/11/01 22:51:28]

Yes, I'm being silly.

+}
+
+CPDF_Linearized::CPDF_Linearized(CPDF_Dictionary* pDict) {
+  m_szFileSize = pDict->GetIntegerFor("L");
+  m_dwFirstPageNo = pDict->GetIntegerFor("P");
+  m_szLastXRefOffset = pDict->GetIntegerFor("T");
+  m_PageCount = pDict->GetIntegerFor("N");
+  m_szFirstPageEndOffset = pDict->GetIntegerFor("E");
+  m_FirstPageObjNum = pDict->GetIntegerFor("O");
+  CPDF_Array* pHintStreamRange = pDict->GetArrayFor("H");
+  size_t nHintStreamSize = pHintStreamRange ? pHintStreamRange->GetCount() : 0;
+  if (nHintStreamSize == 2 || nHintStreamSize == 4) {
+    m_szHintStart = pHintStreamRange->GetIntegerAt(0);
+    m_szHintLength = pHintStreamRange->GetIntegerAt(1);
+  }
+}
+
+CPDF_Linearized::~CPDF_Linearized() {}
+
+bool CPDF_Linearized::HasHintTable() const {
+  return GetPageCount() > 1 && GetHintStart() > 0 && GetHintLength() > 0;
+}