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Refactor QPDF::recoverStreamLength

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This commit is contained in:
m-holger 2024-08-22 13:58:55 +01:00 committed by m-holger
parent 98c14e7740
commit 965f0fcd63
2 changed files with 24 additions and 14 deletions
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36
libqpdf/QPDF.cc
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@ -1390,6 +1390,26 @@ QPDF::Xref_table::insert_free(QPDFObjGen og)
}
}
QPDFObjGen
QPDF::Xref_table::at_offset(qpdf_offset_t offset) const noexcept
{
int id = 0;
int gen = 0;
qpdf_offset_t start = 0;
int i = 0;
for (auto const& item: table) {
auto o = item.offset();
if (start < o && o <= offset) {
start = o;
id = i;
gen = item.gen();
}
++i;
}
return QPDFObjGen(id, gen);
}
void
QPDF::showXRefTable()
{
@ -1690,21 +1710,9 @@ QPDF::recoverStreamLength(
}
if (length) {
auto end = stream_offset + toO(length);
qpdf_offset_t found_offset = 0;
QPDFObjGen found_og;
// Make sure this is inside this object
for (auto const& [current_og, entry]: m->xref_table.as_map()) {
if (entry.getType() == 1) {
qpdf_offset_t obj_offset = entry.getOffset();
if (found_offset < obj_offset && obj_offset < end) {
found_offset = obj_offset;
found_og = current_og;
}
}
}
if (!found_offset || found_og == og) {
auto found = m->xref_table.at_offset(stream_offset + toO(length));
if (found == QPDFObjGen() || found == og) {
// If we are trying to recover an XRef stream the xref table will not contain and
// won't contain any entries, therefore we cannot check the found length. Otherwise we
// found endstream\nendobj within the space allowed for this object, so we're probably

2
libqpdf/qpdf/QPDF_private.hh
View File

@ -87,6 +87,8 @@ class QPDF::Xref_table
return table[static_cast<size_t>(id)].stream_index();
}
QPDFObjGen at_offset(qpdf_offset_t offset) const noexcept;
// Temporary access to underlying map
std::map<QPDFObjGen, QPDFXRefEntry>
as_map()