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Code Issues Releases Wiki Activity

Add new convenience class QPDFObjGen::set

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This commit is contained in:
m-holger 2023-01-05 11:09:44 +00:00
parent a6d7b79e65
commit 9b08017217
2 changed files with 121 additions and 4 deletions
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69
include/qpdf/QPDFObjGen.hh
View File

@ -24,6 +24,10 @@
#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.
@ -31,6 +35,7 @@
class QPDFObjGen
{
public:
// ABI: change to default.
QPDF_DLL
QPDFObjGen() :
obj(0),
@ -84,12 +89,72 @@ class QPDFObjGen
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::Tracker& 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;
int gen;
int obj{0};
int gen{0};
};
#endif // QPDFOBJGEN_HH

56
libqpdf/QPDFObjGen.cc
View File

@ -1,7 +1,12 @@
#include <qpdf/QPDFObjGen.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/QPDFObjectHelper.hh>
#include <qpdf/QPDFObject_private.hh>
#include <stdexcept>
// ABI: inline and pass og by value
std::ostream&
operator<<(std::ostream& os, const QPDFObjGen& og)
{
@ -9,8 +14,55 @@ operator<<(std::ostream& os, const QPDFObjGen& og)
return os;
}
// ABI: inline
std::string
QPDFObjGen::unparse(char separator) const
{
return std::to_string(this->obj) + separator + std::to_string(this->gen);
return std::to_string(obj) + separator + std::to_string(gen);
}
bool
QPDFObjGen::set::add(QPDFObjectHandle const& oh)
{
if (auto* ptr = oh.getObjectPtr()) {
return add(ptr->getObjGen());
} else {
throw std::logic_error("attempt to retrieve QPDFObjGen from "
"uninitialized QPDFObjectHandle");
return false;
}
}
bool
QPDFObjGen::set::add(QPDFObjectHelper const& helper)
{
if (auto* ptr = helper.getObjectHandle().getObjectPtr()) {
return add(ptr->getObjGen());
} else {
throw std::logic_error("attempt to retrieve QPDFObjGen from "
"uninitialized QPDFObjectHandle");
return false;
}
}
void
QPDFObjGen::set::erase(QPDFObjectHandle const& oh)
{
if (auto* ptr = oh.getObjectPtr()) {
erase(ptr->getObjGen());
} else {
throw std::logic_error("attempt to retrieve QPDFObjGen from "
"uninitialized QPDFObjectHandle");
}
}
void
QPDFObjGen::set::erase(QPDFObjectHelper const& helper)
{
if (auto* ptr = helper.getObjectHandle().getObjectPtr()) {
erase(ptr->getObjGen());
} else {
throw std::logic_error("attempt to retrieve QPDFObjGen from "
"uninitialized QPDFObjectHandle");
}
}