1 // Copyright 2016 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 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
6
7 #include "core/fpdfdoc/cpdf_pagelabel.h"
8
9 #include <array>
10 #include <utility>
11
12 #include "core/fpdfapi/parser/cpdf_dictionary.h"
13 #include "core/fpdfapi/parser/cpdf_document.h"
14 #include "core/fpdfapi/parser/fpdf_parser_decode.h"
15 #include "core/fpdfdoc/cpdf_numbertree.h"
16 #include "core/fxcrt/stl_util.h"
17
18 namespace {
19
MakeRoman(int num)20 WideString MakeRoman(int num) {
21 constexpr auto kArabic = fxcrt::ToArray<const int>(
22 {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1});
23 const auto kRoman = fxcrt::ToArray<const WideStringView>(
24 {L"m", L"cm", L"d", L"cd", L"c", L"xc", L"l", L"xl", L"x", L"ix", L"v",
25 L"iv", L"i"});
26 constexpr int kMaxNum = 1000000;
27
28 num %= kMaxNum;
29 int i = 0;
30 WideString result;
31 result.Reserve(10); // Should cover most use cases.
32 while (num > 0) {
33 while (num >= kArabic[i]) {
34 num -= kArabic[i];
35 result += kRoman[i];
36 }
37 ++i;
38 }
39 return result;
40 }
41
MakeLetters(int num)42 WideString MakeLetters(int num) {
43 if (num == 0) {
44 return WideString();
45 }
46
47 constexpr int kMaxCount = 1000;
48 constexpr int kLetterCount = 26;
49
50 --num;
51 const int count = (num / kLetterCount + 1) % kMaxCount;
52 const wchar_t ch = L'a' + num % kLetterCount;
53
54 WideString result;
55 {
56 auto result_span = result.GetBuffer(count);
57 fxcrt::Fill(result_span, ch);
58 result.ReleaseBuffer(count);
59 }
60 return result;
61 }
62
GetLabelNumPortion(int num,const ByteString & style)63 WideString GetLabelNumPortion(int num, const ByteString& style) {
64 if (style.IsEmpty()) {
65 return WideString();
66 }
67 if (style == "D") {
68 return WideString::FormatInteger(num);
69 }
70 if (style == "R") {
71 WideString result = MakeRoman(num);
72 result.MakeUpper();
73 return result;
74 }
75 if (style == "r") {
76 return MakeRoman(num);
77 }
78 if (style == "A") {
79 WideString result = MakeLetters(num);
80 result.MakeUpper();
81 return result;
82 }
83 if (style == "a") {
84 return MakeLetters(num);
85 }
86 return WideString();
87 }
88
89 } // namespace
90
CPDF_PageLabel(CPDF_Document * doc)91 CPDF_PageLabel::CPDF_PageLabel(CPDF_Document* doc) : doc_(doc) {}
92
93 CPDF_PageLabel::~CPDF_PageLabel() = default;
94
GetLabel(int page_index) const95 std::optional<WideString> CPDF_PageLabel::GetLabel(int page_index) const {
96 if (!doc_) {
97 return std::nullopt;
98 }
99
100 if (page_index < 0 || page_index >= doc_->GetPageCount()) {
101 return std::nullopt;
102 }
103
104 const CPDF_Dictionary* root_dict = doc_->GetRoot();
105 if (!root_dict) {
106 return std::nullopt;
107 }
108
109 RetainPtr<const CPDF_Dictionary> labels_dict =
110 root_dict->GetDictFor("PageLabels");
111 if (!labels_dict) {
112 return std::nullopt;
113 }
114
115 CPDF_NumberTree number_tree(std::move(labels_dict));
116 RetainPtr<const CPDF_Object> label_value;
117 std::optional<CPDF_NumberTree::KeyValue> lower_bound =
118 number_tree.GetLowerBound(page_index);
119 if (lower_bound.has_value()) {
120 label_value = lower_bound.value().value;
121 }
122
123 const CPDF_Dictionary* label_dict =
124 label_value ? label_value->GetDirect()->AsDictionary() : nullptr;
125 if (!label_dict) {
126 return WideString::FormatInteger(page_index + 1);
127 }
128
129 WideString label;
130 if (label_dict->KeyExist("P")) {
131 label = label_dict->GetUnicodeTextFor("P");
132 }
133
134 ByteString style = label_dict->GetByteStringFor("S", ByteString());
135 int label_number =
136 page_index - lower_bound.value().key + label_dict->GetIntegerFor("St", 1);
137 label += GetLabelNumPortion(label_number, style);
138 return label;
139 }
140