diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/qpdf/QPDFObjGen.hh | 69 |
1 files changed, 67 insertions, 2 deletions
diff --git a/include/qpdf/QPDFObjGen.hh b/include/qpdf/QPDFObjGen.hh index ccab4ba2..0d14efaf 100644 --- a/include/qpdf/QPDFObjGen.hh +++ b/include/qpdf/QPDFObjGen.hh @@ -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 |