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Code Issues Releases Wiki Activity

Replace QPDF::Writer::getObjectStreamData with getXRefTable

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This commit is contained in:
m-holger 2024-03-04 16:46:31 +00:00
parent ef3a8025fb
commit ae00ee6119
3 changed files with 51 additions and 39 deletions
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16
include/qpdf/QPDF.hh
View File

@ -753,18 +753,18 @@ class QPDF
return qpdf.generateHintStream(new_obj, obj, hint_stream, S, O, compressed);
}
static void
getObjectStreamData(QPDF& qpdf, std::map<int, int>& omap)
{
qpdf.getObjectStreamData(omap);
}
static std::vector<QPDFObjGen>
getCompressibleObjGens(QPDF& qpdf)
{
return qpdf.getCompressibleObjGens();
}
static std::map<QPDFObjGen, QPDFXRefEntry> const&
getXRefTable(QPDF& qpdf)
{
return qpdf.getXRefTableInternal();
}
static size_t
tableSize(QPDF& qpdf)
{
@ -1088,6 +1088,7 @@ class QPDF
// For QPDFWriter:
std::map<QPDFObjGen, QPDFXRefEntry> const& getXRefTableInternal();
size_t tableSize();
// Get lists of all objects in order according to the part of a linearized file that they belong
@ -1108,9 +1109,6 @@ class QPDF
int& O,
bool compressed);
// Map object to object stream that contains it
void getObjectStreamData(std::map<int, int>&);
// Get a list of objects that would be permitted in an object stream.
std::vector<QPDFObjGen> getCompressibleObjGens();

18
libqpdf/QPDF.cc
View File

@ -2369,6 +2369,12 @@ QPDF::getRoot()
std::map<QPDFObjGen, QPDFXRefEntry>
QPDF::getXRefTable()
{
return getXRefTableInternal();
}
std::map<QPDFObjGen, QPDFXRefEntry> const&
QPDF::getXRefTableInternal()
{
if (!m->parsed) {
throw std::logic_error("QPDF::getXRefTable called before parsing.");
@ -2390,18 +2396,6 @@ QPDF::tableSize()
return toS(++max_xref);
}
void
QPDF::getObjectStreamData(std::map<int, int>& omap)
{
for (auto const& iter: m->xref_table) {
QPDFObjGen const& og = iter.first;
QPDFXRefEntry const& entry = iter.second;
if (entry.getType() == 2) {
omap[og.getObj()] = entry.getObjStreamNumber();
}
}
}
std::vector<QPDFObjGen>
QPDF::getCompressibleObjGens()
{

56
libqpdf/QPDFWriter.cc
View File

@ -1936,12 +1936,7 @@ QPDFWriter::initializeSpecialStreams()
void
QPDFWriter::preserveObjectStreams()
{
std::map<int, int> omap;
QPDF::Writer::getObjectStreamData(m->pdf, omap);
if (omap.empty()) {
m->obj.streams_empty = true;
return;
}
auto const& xref = QPDF::Writer::getXRefTable(m->pdf);
// Our object_to_object_stream map has to map ObjGen -> ObjGen since we may be generating object
// streams out of old objects that have generation numbers greater than zero. However in an
// existing PDF, all object stream objects and all objects in them must have generation 0
@ -1949,20 +1944,45 @@ QPDFWriter::preserveObjectStreams()
// that are not allowed to be in object streams. In addition to removing objects that were
// erroneously included in object streams in the source PDF, it also prevents unreferenced
// objects from being included.
std::set<QPDFObjGen> eligible;
if (!m->preserve_unreferenced_objects) {
std::vector<QPDFObjGen> eligible_v = QPDF::Writer::getCompressibleObjGens(m->pdf);
eligible = std::set<QPDFObjGen>(eligible_v.begin(), eligible_v.end());
}
QTC::TC("qpdf", "QPDFWriter preserve object streams", m->preserve_unreferenced_objects ? 0 : 1);
for (auto iter: omap) {
QPDFObjGen og(iter.first, 0);
if (eligible.count(og) || m->preserve_unreferenced_objects) {
m->obj[iter.first].object_stream = iter.second;
} else {
QTC::TC("qpdf", "QPDFWriter exclude from object stream");
auto iter = xref.cbegin();
auto end = xref.cend();
// Start by scanning for first compressed object in case we don't have any object streams to
// process.
for (; iter != end; ++iter) {
if (iter->second.getType() == 2) {
// Pdf contains object streams.
QTC::TC(
"qpdf",
"QPDFWriter preserve object streams",
m->preserve_unreferenced_objects ? 0 : 1);
if (m->preserve_unreferenced_objects) {
for (; iter != end; ++iter) {
if (iter->second.getType() == 2) {
m->obj[iter->first].object_stream = iter->second.getObjStreamNumber();
}
}
} else {
std::set<QPDFObjGen> eligible;
std::vector<QPDFObjGen> eligible_v = QPDF::Writer::getCompressibleObjGens(m->pdf);
eligible = std::set<QPDFObjGen>(eligible_v.begin(), eligible_v.end());
for (; iter != end; ++iter) {
if (iter->second.getType() == 2) {
QPDFObjGen og(iter->first.getObj(), 0);
if (eligible.count(og)) {
m->obj[iter->first].object_stream = iter->second.getObjStreamNumber();
} else {
QTC::TC("qpdf", "QPDFWriter exclude from object stream");
}
}
}
}
return;
}
}
// No compressed objects found.
m->obj.streams_empty = true;
}
void