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// Copyright 2017 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/fpdfdoc/cpdf_structtree.h"
#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/cpdf_document.h"
#include "core/fpdfapi/parser/cpdf_number.h"
#include "core/fpdfapi/parser/cpdf_reference.h"
#include "core/fpdfdoc/cpdf_numbertree.h"
#include "core/fpdfdoc/cpdf_structelement.h"
namespace {
bool IsTagged(const CPDF_Document* pDoc) {
const CPDF_Dictionary* pCatalog = pDoc->GetRoot();
const CPDF_Dictionary* pMarkInfo = pCatalog->GetDictFor("MarkInfo");
return pMarkInfo && pMarkInfo->GetIntegerFor("Marked");
}
} // namespace
// static
std::unique_ptr<CPDF_StructTree> CPDF_StructTree::LoadPage(
const CPDF_Document* pDoc,
const CPDF_Dictionary* pPageDict) {
if (!IsTagged(pDoc))
return nullptr;
auto pTree = pdfium::MakeUnique<CPDF_StructTree>(pDoc);
pTree->LoadPageTree(pPageDict);
return pTree;
}
CPDF_StructTree::CPDF_StructTree(const CPDF_Document* pDoc)
: m_pTreeRoot(pDoc->GetRoot()->GetDictFor("StructTreeRoot")),
m_pRoleMap(m_pTreeRoot ? m_pTreeRoot->GetDictFor("RoleMap") : nullptr) {}
CPDF_StructTree::~CPDF_StructTree() = default;
void CPDF_StructTree::LoadPageTree(const CPDF_Dictionary* pPageDict) {
m_pPage = pPageDict;
if (!m_pTreeRoot)
return;
const CPDF_Object* pKids = m_pTreeRoot->GetDirectObjectFor("K");
if (!pKids)
return;
uint32_t dwKids = 0;
if (pKids->IsDictionary())
dwKids = 1;
else if (const CPDF_Array* pArray = pKids->AsArray())
dwKids = pArray->GetCount();
else
return;
m_Kids.clear();
m_Kids.resize(dwKids);
const CPDF_Dictionary* pParentTree = m_pTreeRoot->GetDictFor("ParentTree");
if (!pParentTree)
return;
CPDF_NumberTree parent_tree(pParentTree);
int parents_id = pPageDict->GetIntegerFor("StructParents", -1);
if (parents_id < 0)
return;
const CPDF_Array* pParentArray = ToArray(parent_tree.LookupValue(parents_id));
if (!pParentArray)
return;
StructElementMap element_map;
for (size_t i = 0; i < pParentArray->GetCount(); i++) {
if (const CPDF_Dictionary* pParent = pParentArray->GetDictAt(i))
AddPageNode(pParent, &element_map, 0);
}
}
RetainPtr<CPDF_StructElement> CPDF_StructTree::AddPageNode(
const CPDF_Dictionary* pDict,
StructElementMap* map,
int nLevel) {
static constexpr int kStructTreeMaxRecursion = 32;
if (nLevel > kStructTreeMaxRecursion)
return nullptr;
auto it = map->find(pDict);
if (it != map->end())
return it->second;
auto pElement = pdfium::MakeRetain<CPDF_StructElement>(this, nullptr, pDict);
(*map)[pDict] = pElement;
const CPDF_Dictionary* pParent = pDict->GetDictFor("P");
if (!pParent || pParent->GetStringFor("Type") == "StructTreeRoot") {
if (!AddTopLevelNode(pDict, pElement))
map->erase(pDict);
return pElement;
}
RetainPtr<CPDF_StructElement> pParentElement =
AddPageNode(pParent, map, nLevel + 1);
bool bSave = false;
for (CPDF_StructKid& kid : *pParentElement->GetKids()) {
if (kid.m_Type == CPDF_StructKid::Element && kid.m_pDict == pDict) {
kid.m_pElement = pElement;
bSave = true;
}
}
if (!bSave)
map->erase(pDict);
return pElement;
}
bool CPDF_StructTree::AddTopLevelNode(
const CPDF_Dictionary* pDict,
const RetainPtr<CPDF_StructElement>& pElement) {
const CPDF_Object* pObj = m_pTreeRoot->GetDirectObjectFor("K");
if (!pObj)
return false;
if (pObj->IsDictionary()) {
if (pObj->GetObjNum() != pDict->GetObjNum())
return false;
m_Kids[0] = pElement;
}
const CPDF_Array* pTopKids = pObj->AsArray();
if (!pTopKids)
return true;
bool bSave = false;
for (size_t i = 0; i < pTopKids->GetCount(); i++) {
const CPDF_Reference* pKidRef = ToReference(pTopKids->GetObjectAt(i));
if (pKidRef && pKidRef->GetRefObjNum() == pDict->GetObjNum()) {
m_Kids[i] = pElement;
bSave = true;
}
}
return bSave;
}
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