QPDFObjGen.hh
3.96 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
// Copyright (c) 2005-2024 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under
// the License.
//
// Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic
// License. At your option, you may continue to consider qpdf to be licensed under those terms.
// Please see the manual for additional information.
#ifndef QPDFOBJGEN_HH
#define QPDFOBJGEN_HH
#include <qpdf/DLL.h>
#include <iostream>
#include <set>
class QPDFObjectHandle;
class QPDFObjectHelper;
// This class represents an object ID and generation pair. It is suitable to use as a key in a map
// or set.
class QPDFObjGen
{
public:
// ABI: change to default.
QPDF_DLL
QPDFObjGen()
{
}
QPDF_DLL
explicit QPDFObjGen(int obj, int gen) :
obj(obj),
gen(gen)
{
}
QPDF_DLL
bool
operator<(QPDFObjGen const& rhs) const
{
return (obj < rhs.obj) || ((obj == rhs.obj) && (gen < rhs.gen));
}
QPDF_DLL
bool
operator==(QPDFObjGen const& rhs) const
{
return (obj == rhs.obj) && (gen == rhs.gen);
}
QPDF_DLL
bool
operator!=(QPDFObjGen const& rhs) const
{
return (obj != rhs.obj) || (gen != rhs.gen);
}
QPDF_DLL
int
getObj() const
{
return obj;
}
QPDF_DLL
int
getGen() const
{
return gen;
}
QPDF_DLL
bool
isIndirect() const
{
return obj != 0;
}
QPDF_DLL
std::string unparse(char separator = ',') const;
QPDF_DLL
friend std::ostream& operator<<(std::ostream& os, const QPDFObjGen& og);
// Convenience class for loop detection when processing objects.
//
// The class adds 'add' methods to a std::set<QPDFObjGen> which allows to test whether an
// QPDFObjGen is present in the set and to insert it in a single operation. The 'add' method is
// overloaded to take a QPDFObjGen, QPDFObjectHandle or an QPDFObjectHelper as parameter.
//
// The erase method is modified to ignore requests to erase QPDFObjGen(0, 0).
//
// Usage example:
//
// void process_object(QPDFObjectHandle oh, QPDFObjGen::set& seen)
// {
// if (seen.add(oh)) {
// // handle first encounter of oh
// } else {
// // handle loop / subsequent encounter of oh
// }
// }
class QPDF_DLL_CLASS set: public std::set<QPDFObjGen>
{
public:
// Add 'og' to the set. Return false if 'og' is already present in the set. Attempts to
// insert QPDFObjGen(0, 0) are ignored.
QPDF_DLL
bool
add(QPDFObjGen og)
{
if (og.isIndirect()) {
if (count(og) > 0) {
return false;
}
emplace(og);
}
return true;
}
QPDF_DLL
bool add(QPDFObjectHandle const& oh);
QPDF_DLL
bool add(QPDFObjectHelper const& oh);
QPDF_DLL
void
erase(QPDFObjGen og)
{
if (og.isIndirect()) {
std::set<QPDFObjGen>::erase(og);
}
}
QPDF_DLL
void erase(QPDFObjectHandle const& oh);
QPDF_DLL
void erase(QPDFObjectHelper const& oh);
};
private:
// This class does not use the Members pattern to avoid a memory allocation for every one of
// these. A lot of these get created and destroyed.
int obj{0};
int gen{0};
};
#endif // QPDFOBJGEN_HH