1 // Copyright 2018 The PDFium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "core/fpdfapi/parser/cpdf_cross_ref_table.h"
6
7 #include <utility>
8
9 #include "core/fpdfapi/parser/cpdf_dictionary.h"
10 #include "core/fpdfapi/parser/cpdf_parser.h"
11 #include "core/fxcrt/check_op.h"
12 #include "core/fxcrt/containers/contains.h"
13
14 // static
MergeUp(std::unique_ptr<CPDF_CrossRefTable> current,std::unique_ptr<CPDF_CrossRefTable> top)15 std::unique_ptr<CPDF_CrossRefTable> CPDF_CrossRefTable::MergeUp(
16 std::unique_ptr<CPDF_CrossRefTable> current,
17 std::unique_ptr<CPDF_CrossRefTable> top) {
18 if (!current)
19 return top;
20
21 if (!top)
22 return current;
23
24 current->Update(std::move(top));
25 return current;
26 }
27
28 CPDF_CrossRefTable::CPDF_CrossRefTable() = default;
29
CPDF_CrossRefTable(RetainPtr<CPDF_Dictionary> trailer,uint32_t trailer_object_number)30 CPDF_CrossRefTable::CPDF_CrossRefTable(RetainPtr<CPDF_Dictionary> trailer,
31 uint32_t trailer_object_number)
32 : trailer_(std::move(trailer)),
33 trailer_object_number_(trailer_object_number) {}
34
35 CPDF_CrossRefTable::~CPDF_CrossRefTable() = default;
36
AddCompressed(uint32_t obj_num,uint32_t archive_obj_num,uint32_t archive_obj_index)37 void CPDF_CrossRefTable::AddCompressed(uint32_t obj_num,
38 uint32_t archive_obj_num,
39 uint32_t archive_obj_index) {
40 CHECK_LT(obj_num, CPDF_Parser::kMaxObjectNumber);
41 CHECK_LT(archive_obj_num, CPDF_Parser::kMaxObjectNumber);
42
43 auto& info = objects_info_[obj_num];
44 if (info.gennum > 0)
45 return;
46
47 // Don't add known object streams to object streams.
48 if (info.is_object_stream_flag) {
49 return;
50 }
51
52 info.type = ObjectType::kCompressed;
53 info.archive.obj_num = archive_obj_num;
54 info.archive.obj_index = archive_obj_index;
55 info.gennum = 0;
56
57 objects_info_[archive_obj_num].is_object_stream_flag = true;
58 }
59
AddNormal(uint32_t obj_num,uint16_t gen_num,bool is_object_stream,FX_FILESIZE pos)60 void CPDF_CrossRefTable::AddNormal(uint32_t obj_num,
61 uint16_t gen_num,
62 bool is_object_stream,
63 FX_FILESIZE pos) {
64 CHECK_LT(obj_num, CPDF_Parser::kMaxObjectNumber);
65
66 auto& info = objects_info_[obj_num];
67 if (info.gennum > gen_num)
68 return;
69
70 info.type = ObjectType::kNormal;
71 info.is_object_stream_flag |= is_object_stream;
72 info.gennum = gen_num;
73 info.pos = pos;
74 }
75
SetFree(uint32_t obj_num,uint16_t gen_num)76 void CPDF_CrossRefTable::SetFree(uint32_t obj_num, uint16_t gen_num) {
77 CHECK_LT(obj_num, CPDF_Parser::kMaxObjectNumber);
78
79 auto& info = objects_info_[obj_num];
80 info.type = ObjectType::kFree;
81 info.gennum = gen_num;
82 info.pos = 0;
83 }
84
SetTrailer(RetainPtr<CPDF_Dictionary> trailer,uint32_t trailer_object_number)85 void CPDF_CrossRefTable::SetTrailer(RetainPtr<CPDF_Dictionary> trailer,
86 uint32_t trailer_object_number) {
87 trailer_ = std::move(trailer);
88 trailer_object_number_ = trailer_object_number;
89 }
90
GetObjectInfo(uint32_t obj_num) const91 const CPDF_CrossRefTable::ObjectInfo* CPDF_CrossRefTable::GetObjectInfo(
92 uint32_t obj_num) const {
93 const auto it = objects_info_.find(obj_num);
94 return it != objects_info_.end() ? &it->second : nullptr;
95 }
96
Update(std::unique_ptr<CPDF_CrossRefTable> new_cross_ref)97 void CPDF_CrossRefTable::Update(
98 std::unique_ptr<CPDF_CrossRefTable> new_cross_ref) {
99 UpdateInfo(std::move(new_cross_ref->objects_info_));
100 UpdateTrailer(std::move(new_cross_ref->trailer_));
101 }
102
SetObjectMapSize(uint32_t size)103 void CPDF_CrossRefTable::SetObjectMapSize(uint32_t size) {
104 if (size == 0) {
105 objects_info_.clear();
106 return;
107 }
108
109 objects_info_.erase(objects_info_.lower_bound(size), objects_info_.end());
110
111 if (!pdfium::Contains(objects_info_, size - 1)) {
112 objects_info_[size - 1].pos = 0;
113 }
114 }
115
UpdateInfo(std::map<uint32_t,ObjectInfo> new_objects_info)116 void CPDF_CrossRefTable::UpdateInfo(
117 std::map<uint32_t, ObjectInfo> new_objects_info) {
118 if (new_objects_info.empty()) {
119 return;
120 }
121
122 if (objects_info_.empty()) {
123 objects_info_ = std::move(new_objects_info);
124 return;
125 }
126
127 auto cur_it = objects_info_.begin();
128 auto new_it = new_objects_info.begin();
129 while (cur_it != objects_info_.end() && new_it != new_objects_info.end()) {
130 if (cur_it->first == new_it->first) {
131 if (new_it->second.type == ObjectType::kNormal &&
132 cur_it->second.type == ObjectType::kNormal &&
133 cur_it->second.is_object_stream_flag) {
134 new_it->second.is_object_stream_flag = true;
135 }
136 ++cur_it;
137 ++new_it;
138 } else if (cur_it->first < new_it->first) {
139 new_objects_info.insert(new_it, *cur_it);
140 ++cur_it;
141 } else {
142 new_it = new_objects_info.lower_bound(cur_it->first);
143 }
144 }
145 for (; cur_it != objects_info_.end(); ++cur_it) {
146 new_objects_info.insert(new_objects_info.end(), *cur_it);
147 }
148 objects_info_ = std::move(new_objects_info);
149 }
150
UpdateTrailer(RetainPtr<CPDF_Dictionary> new_trailer)151 void CPDF_CrossRefTable::UpdateTrailer(RetainPtr<CPDF_Dictionary> new_trailer) {
152 if (!new_trailer)
153 return;
154
155 if (!trailer_) {
156 trailer_ = std::move(new_trailer);
157 return;
158 }
159
160 new_trailer->SetFor("XRefStm", trailer_->RemoveFor("XRefStm"));
161 new_trailer->SetFor("Prev", trailer_->RemoveFor("Prev"));
162
163 for (const auto& key : new_trailer->GetKeys())
164 trailer_->SetFor(key, new_trailer->RemoveFor(key.AsStringView()));
165 }
166