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Refactor Xref_table::read_table

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Rename to Xref_table::process_section.
Process trailer processing subsection entries.
This commit is contained in:
m-holger 2024-08-14 14:10:50 +01:00
parent ed65619428
commit 39df5936fe
2 changed files with 27 additions and 25 deletions
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50
libqpdf/QPDF.cc
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@ -732,7 +732,7 @@ QPDF::Xref_table::read(qpdf_offset_t xref_offset)
while (QUtil::is_space(buf[skip])) { while (QUtil::is_space(buf[skip])) {
++skip; ++skip;
} }
xref_offset = read_table(xref_offset + skip); xref_offset = process_section(xref_offset + skip);
} else { } else {
xref_offset = read_stream(xref_offset); xref_offset = read_stream(xref_offset);
} }
@ -994,11 +994,32 @@ QPDF::Xref_table::read_entry(qpdf_offset_t& f1, int& f2, char& type)
// Read a single cross-reference table section and associated trailer. // Read a single cross-reference table section and associated trailer.
qpdf_offset_t qpdf_offset_t
QPDF::Xref_table::read_table(qpdf_offset_t xref_offset) QPDF::Xref_table::process_section(qpdf_offset_t xref_offset)
{ {
file->seek(xref_offset, SEEK_SET); file->seek(xref_offset, SEEK_SET);
std::string line; std::string line;
auto subs = subsections(line); auto subs = subsections(line);
auto cur_trailer_offset = file->tell();
auto cur_trailer = read_trailer();
if (!cur_trailer.isDictionary()) {
QTC::TC("qpdf", "QPDF missing trailer");
throw qpdf.damagedPDF("", "expected trailer dictionary");
}
if (!trailer_) {
trailer_ = cur_trailer;
if (!trailer_.hasKey("/Size")) {
QTC::TC("qpdf", "QPDF trailer lacks size");
throw qpdf.damagedPDF("trailer", "trailer dictionary lacks /Size key");
}
if (!trailer_.getKey("/Size").isInteger()) {
QTC::TC("qpdf", "QPDF trailer size not integer");
throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is not an integer");
}
}
for (auto [obj, num, offset]: subs) { for (auto [obj, num, offset]: subs) {
file->seek(offset, SEEK_SET); file->seek(offset, SEEK_SET);
for (qpdf_offset_t i = obj; i - num < obj; ++i) { for (qpdf_offset_t i = obj; i - num < obj; ++i) {
@ -1027,26 +1048,6 @@ QPDF::Xref_table::read_table(qpdf_offset_t xref_offset)
} }
} }
// Set offset to previous xref table if any
auto cur_trailer = read_trailer();
if (!cur_trailer.isDictionary()) {
QTC::TC("qpdf", "QPDF missing trailer");
throw qpdf.damagedPDF("", "expected trailer dictionary");
}
if (!trailer_) {
trailer_ = cur_trailer;
if (!trailer_.hasKey("/Size")) {
QTC::TC("qpdf", "QPDF trailer lacks size");
throw qpdf.damagedPDF("trailer", "trailer dictionary lacks /Size key");
}
if (!trailer_.getKey("/Size").isInteger()) {
QTC::TC("qpdf", "QPDF trailer size not integer");
throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is not an integer");
}
}
if (cur_trailer.hasKey("/XRefStm")) { if (cur_trailer.hasKey("/XRefStm")) {
if (ignore_streams_) { if (ignore_streams_) {
QTC::TC("qpdf", "QPDF ignoring XRefStm in trailer"); QTC::TC("qpdf", "QPDF ignoring XRefStm in trailer");
@ -1056,7 +1057,7 @@ QPDF::Xref_table::read_table(qpdf_offset_t xref_offset)
// /Prev key instead of the xref stream's. // /Prev key instead of the xref stream's.
(void)read_stream(cur_trailer.getKey("/XRefStm").getIntValue()); (void)read_stream(cur_trailer.getKey("/XRefStm").getIntValue());
} else { } else {
throw qpdf.damagedPDF("xref stream", xref_offset, "invalid /XRefStm"); throw qpdf.damagedPDF("xref stream", cur_trailer_offset, "invalid /XRefStm");
} }
} }
} }
@ -1064,7 +1065,8 @@ QPDF::Xref_table::read_table(qpdf_offset_t xref_offset)
if (cur_trailer.hasKey("/Prev")) { if (cur_trailer.hasKey("/Prev")) {
if (!cur_trailer.getKey("/Prev").isInteger()) { if (!cur_trailer.getKey("/Prev").isInteger()) {
QTC::TC("qpdf", "QPDF trailer prev not integer"); QTC::TC("qpdf", "QPDF trailer prev not integer");
throw qpdf.damagedPDF("trailer", "/Prev key in trailer dictionary is not an integer"); throw qpdf.damagedPDF(
"trailer", cur_trailer_offset, "/Prev key in trailer dictionary is not an integer");
} }
QTC::TC("qpdf", "QPDF prev key in trailer dictionary"); QTC::TC("qpdf", "QPDF prev key in trailer dictionary");
return cur_trailer.getKey("/Prev").getIntValue(); return cur_trailer.getKey("/Prev").getIntValue();

2
libqpdf/qpdf/QPDF_private.hh
View File

@ -124,7 +124,7 @@ class QPDF::Xref_table
void read(qpdf_offset_t offset); void read(qpdf_offset_t offset);
// Methods to parse tables // Methods to parse tables
qpdf_offset_t read_table(qpdf_offset_t offset); qpdf_offset_t process_section(qpdf_offset_t offset);
std::vector<Subsection> subsections(std::string& line); std::vector<Subsection> subsections(std::string& line);
Subsection subsection(std::string const& line); Subsection subsection(std::string const& line);
bool read_entry(qpdf_offset_t& f1, int& f2, char& type); bool read_entry(qpdf_offset_t& f1, int& f2, char& type);