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qpdf/qpdf/fix-qdf.cc
2020-01-14 11:53:19 -05:00

512 lines
14 KiB
C++

#include <qpdf/QUtil.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/QPDFXRefEntry.hh>
#include <qpdf/QIntC.hh>
#include <cstdio>
#include <iostream>
#include <cstring>
#include <regex>
static char const* whoami = 0;
static void usage()
{
std::cerr << "Usage: " << whoami << " [filename]" << std::endl;
exit(2);
}
class QdfFixer
{
public:
QdfFixer(std::string const& filename);
void processLines(std::list<std::string>& lines);
private:
void fatal(std::string const&);
void checkObjId(std::string const& obj_id);
void adjustOstreamXref();
void writeOstream();
void writeBinary(unsigned long long val, size_t bytes);
std::string filename;
enum {
st_top,
st_in_obj,
st_in_stream,
st_after_stream,
st_in_ostream_dict,
st_in_ostream_offsets,
st_in_ostream_outer,
st_in_ostream_obj,
st_in_xref_stream_dict,
st_in_length,
st_at_xref,
st_before_trailer,
st_in_trailer,
st_done,
} state;
size_t lineno;
qpdf_offset_t offset;
qpdf_offset_t last_offset;
int last_obj;
std::vector<QPDFXRefEntry> xref;
qpdf_offset_t stream_start;
size_t stream_length;
qpdf_offset_t xref_offset;
size_t xref_f1_nbytes;
size_t xref_f2_nbytes;
size_t xref_size;
std::vector<std::string> ostream;
std::vector<qpdf_offset_t> ostream_offsets;
std::vector<std::string> ostream_discarded;
size_t ostream_idx;
int ostream_id;
std::string ostream_extends;
};
QdfFixer::QdfFixer(std::string const& filename) :
filename(filename),
state(st_top),
lineno(0),
offset(0),
last_offset(0),
last_obj(0),
stream_start(0),
stream_length(0),
xref_offset(0),
xref_f1_nbytes(0),
xref_f2_nbytes(0),
xref_size(0),
ostream_idx(0),
ostream_id(0)
{
}
void
QdfFixer::fatal(std::string const& msg)
{
std::cerr << msg << std::endl;
exit(2);
}
void
QdfFixer::processLines(std::list<std::string>& lines)
{
static std::regex re_n_0_obj("^(\\d+) 0 obj\n$");
static std::regex re_xref("^xref\n$");
static std::regex re_stream("^stream\n$");
static std::regex re_endobj("^endobj\n$");
static std::regex re_type_objstm("/Type /ObjStm");
static std::regex re_type_xref("/Type /XRef");
static std::regex re_extends("/Extends (\\d+ 0 R)");
static std::regex re_ostream_obj("^%% Object stream: object (\\d+)");
static std::regex re_endstream("^endstream\n$");
static std::regex re_length_or_w("/(Length|W) ");
static std::regex re_size("/Size ");
static std::regex re_ignore_newline("^%QDF: ignore_newline\n$");
static std::regex re_num("^\\d+\n$");
static std::regex re_trailer("^trailer <<");
static std::regex re_size_n("^ /Size \\d+\n$");
static std::regex re_dict_end("^>>\n$");
lineno = 0;
for (auto line: lines)
{
++lineno;
last_offset = offset;
offset += QIntC::to_offset(line.length());
std::smatch m;
auto matches = [&m, &line](std::regex& r){
return std::regex_search(line, m, r); };
if (state == st_top)
{
if (matches(re_n_0_obj))
{
checkObjId(m[1].str());
state = st_in_obj;
}
else if (matches(re_xref))
{
xref_offset = last_offset;
state = st_at_xref;
}
std::cout << line;
}
else if (state == st_in_obj)
{
std::cout << line;
if (matches(re_stream))
{
state = st_in_stream;
stream_start = offset;
}
else if (matches(re_endobj))
{
state = st_top;
}
else if (matches(re_type_objstm))
{
state = st_in_ostream_dict;
ostream_id = last_obj;
}
else if (matches(re_type_xref))
{
xref_offset = xref.back().getOffset();
xref_f1_nbytes = 0;
auto t = xref_offset;
while (t)
{
t >>= 8;
++xref_f1_nbytes;
}
// Figure out how many bytes we need for ostream
// index. Make sure we get at least 1 byte even if
// there are no object streams.
int max_objects = 1;
for (auto e: xref)
{
if ((e.getType() == 2) &&
(e.getObjStreamIndex() > max_objects))
{
max_objects = e.getObjStreamIndex();
}
}
while (max_objects)
{
max_objects >>=8;
++xref_f2_nbytes;
}
auto esize = 1 + xref_f1_nbytes + xref_f2_nbytes;
xref_size = 1 + xref.size();
auto length = xref_size * esize;
std::cout << " /Length " << length << "\n"
<< " /W [ 1 " << xref_f1_nbytes << " "
<< xref_f2_nbytes << " ]" << "\n";
state = st_in_xref_stream_dict;
}
}
else if (state == st_in_ostream_dict)
{
if (matches(re_stream))
{
state = st_in_ostream_offsets;
}
else
{
ostream_discarded.push_back(line);
if (matches(re_extends))
{
ostream_extends = m[1].str();
}
}
// discard line
}
else if (state == st_in_ostream_offsets)
{
if (matches(re_ostream_obj))
{
checkObjId(m[1].str());
stream_start = last_offset;
state = st_in_ostream_outer;
ostream.push_back(line);
}
else
{
ostream_discarded.push_back(line);
}
// discard line
}
else if (state == st_in_ostream_outer)
{
adjustOstreamXref();
ostream_offsets.push_back(last_offset - stream_start);
state = st_in_ostream_obj;
ostream.push_back(line);
}
else if (state == st_in_ostream_obj)
{
ostream.push_back(line);
if (matches(re_ostream_obj))
{
checkObjId(m[1].str());
state = st_in_ostream_outer;
}
else if (matches(re_endstream))
{
stream_length = QIntC::to_size(last_offset - stream_start);
writeOstream();
state = st_in_obj;
}
}
else if (state == st_in_xref_stream_dict)
{
if (matches(re_length_or_w))
{
// already printed
}
else if (matches(re_size))
{
auto xref_size = 1 + xref.size();
std::cout << " /Size " << xref_size << "\n";
}
else
{
std::cout << line;
}
if (matches(re_stream))
{
writeBinary(0, 1);
writeBinary(0, xref_f1_nbytes);
writeBinary(0, xref_f2_nbytes);
for (auto x: xref)
{
unsigned long long f1 = 0;
unsigned long long f2 = 0;
unsigned int type = QIntC::to_uint(x.getType());
if (1 == type)
{
f1 = QIntC::to_ulonglong(x.getOffset());
}
else
{
f1 = QIntC::to_ulonglong(x.getObjStreamNumber());
f2 = QIntC::to_ulonglong(x.getObjStreamIndex());
}
writeBinary(type, 1);
writeBinary(f1, xref_f1_nbytes);
writeBinary(f2, xref_f2_nbytes);
}
std::cout << "\nendstream\nendobj\n\n"
<< "startxref\n" << xref_offset << "\n%%EOF\n";
state = st_done;
}
}
else if (state == st_in_stream)
{
if (matches(re_endstream))
{
stream_length = QIntC::to_size(last_offset - stream_start);
state = st_after_stream;
}
std::cout << line;
}
else if (state == st_after_stream)
{
if (matches(re_ignore_newline))
{
--stream_length;
}
else if (matches(re_n_0_obj))
{
checkObjId(m[1].str());
state = st_in_length;
}
std::cout << line;
}
else if (state == st_in_length)
{
if (! matches(re_num))
{
fatal(filename + ":" + QUtil::uint_to_string(lineno) +
": expected integer");
}
std::string new_length =
QUtil::uint_to_string(stream_length) + "\n";
offset -= QIntC::to_offset(line.length());
offset += QIntC::to_offset(new_length.length());
std::cout << new_length;
state = st_top;
}
else if (state == st_at_xref)
{
auto n = xref.size();
std::cout << "0 " << 1 + n << "\n0000000000 65535 f \n";
for (auto e: xref)
{
std::cout << QUtil::int_to_string(e.getOffset(), 10)
<< " 00000 n \n";
}
state = st_before_trailer;
}
else if (state == st_before_trailer)
{
if (matches(re_trailer))
{
std::cout << line;
state = st_in_trailer;
}
// no output
}
else if (state == st_in_trailer)
{
if (matches(re_size_n))
{
std::cout << " /Size " << 1 + xref.size() << "\n";
}
else
{
std::cout << line;
}
if (matches(re_dict_end))
{
std::cout << "startxref\n" << xref_offset<< "\n%%EOF\n";
state = st_done;
}
}
else if (state == st_done)
{
// ignore
}
}
}
void
QdfFixer::checkObjId(std::string const& cur_obj_str)
{
int cur_obj = QUtil::string_to_int(cur_obj_str.c_str());
if (cur_obj != last_obj + 1)
{
fatal(filename + ":" + QUtil::uint_to_string(lineno) +
": expected object " + QUtil::int_to_string(last_obj + 1));
}
last_obj = cur_obj;
xref.push_back(QPDFXRefEntry(1, QIntC::to_offset(last_offset), 0));
}
void
QdfFixer::adjustOstreamXref()
{
xref.pop_back();
xref.push_back(QPDFXRefEntry(2, ostream_id, QIntC::to_int(ostream_idx++)));
}
void
QdfFixer::writeOstream()
{
auto first = ostream_offsets.at(0);
auto onum = ostream_id;
std::string offsets;
auto n = ostream_offsets.size();
for (auto iter = ostream_offsets.begin();
iter != ostream_offsets.end(); ++iter)
{
(*iter) -= QIntC::to_offset(first);
++onum;
offsets += QUtil::int_to_string(onum) + " " +
QUtil::int_to_string(*iter) + "\n";
}
auto offset_adjust = QIntC::to_offset(offsets.size());
first += offset_adjust;
stream_length += QIntC::to_size(offset_adjust);
std::string dict_data = "";
dict_data += " /Length " + QUtil::uint_to_string(stream_length) + "\n";
dict_data += " /N " + QUtil::uint_to_string(n) + "\n";
dict_data += " /First " + QUtil::int_to_string(first) + "\n";
if (! ostream_extends.empty())
{
dict_data += " /Extends " + ostream_extends + "\n";
}
dict_data += ">>\n";
offset_adjust += QIntC::to_offset(dict_data.length());
std::cout << dict_data
<< "stream\n"
<< offsets;
for (auto o: ostream)
{
std::cout << o;
}
for (auto o: ostream_discarded)
{
offset -= QIntC::to_offset(o.length());
}
offset += offset_adjust;
ostream_idx = 0;
ostream_id = 0;
ostream.clear();
ostream_offsets.clear();
ostream_discarded.clear();
ostream_extends.clear();
}
void
QdfFixer::writeBinary(unsigned long long val, size_t bytes)
{
if (bytes > sizeof(unsigned long long))
{
throw std::logic_error(
"fix-qdf::writeBinary called with too many bytes");
}
std::string data;
data.reserve(bytes);
for (size_t i = 0; i < bytes; ++i)
{
data.append(1, '\0');
}
for (size_t i = 0; i < bytes; ++i)
{
data.at(bytes - i - 1) =
static_cast<char>(QIntC::to_uchar(val & 0xff));
val >>= 8;
}
std::cout << data;
}
static int realmain(int argc, char* argv[])
{
whoami = QUtil::getWhoami(argv[0]);
QUtil::setLineBuf(stdout);
char const* filename = 0;
if (argc > 2)
{
usage();
}
else if ((argc > 1) && (strcmp(argv[1], "--version") == 0))
{
std::cout << whoami << " from qpdf version "
<< QPDF::QPDFVersion() << std::endl;
return 0;
}
else if ((argc > 1) && (strcmp(argv[1], "--help") == 0))
{
usage();
}
else if (argc == 2)
{
filename = argv[1];
}
std::list<std::string> lines;
if (filename == 0)
{
filename = "standard input";
QUtil::binary_stdin();
lines = QUtil::read_lines_from_file(stdin, true);
}
else
{
lines = QUtil::read_lines_from_file(filename, true);
}
QUtil::binary_stdout();
QdfFixer qf(filename);
qf.processLines(lines);
return 0;
}
#ifdef WINDOWS_WMAIN
extern "C"
int wmain(int argc, wchar_t* argv[])
{
return QUtil::call_main_from_wmain(argc, argv, realmain);
}
#else
int main(int argc, char* argv[])
{
return realmain(argc, argv);
}
#endif