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// Copyright (c) 2005-2023 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
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