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qpdf/libqpdf/QPDF.cc
Jay Berkenbilt 6ee761fc86 Prepare 8.2.1 release
2018-08-18 10:56:19 -04:00

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#include <qpdf/qpdf-config.h> // include first for large file support
#include <qpdf/QPDF.hh>
#include <vector>
#include <map>
#include <algorithm>
#include <string.h>
#include <memory.h>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/Pipeline.hh>
#include <qpdf/Pl_Discard.hh>
#include <qpdf/FileInputSource.hh>
#include <qpdf/BufferInputSource.hh>
#include <qpdf/OffsetInputSource.hh>
#include <qpdf/QPDFExc.hh>
#include <qpdf/QPDF_Null.hh>
#include <qpdf/QPDF_Dictionary.hh>
std::string QPDF::qpdf_version = "8.2.1";
static char const* EMPTY_PDF =
"%PDF-1.3\n"
"1 0 obj\n"
"<< /Type /Catalog /Pages 2 0 R >>\n"
"endobj\n"
"2 0 obj\n"
"<< /Type /Pages /Kids [] /Count 0 >>\n"
"endobj\n"
"xref\n"
"0 3\n"
"0000000000 65535 f \n"
"0000000009 00000 n \n"
"0000000058 00000 n \n"
"trailer << /Size 3 /Root 1 0 R >>\n"
"startxref\n"
"110\n"
"%%EOF\n";
void
QPDF::CopiedStreamDataProvider::provideStreamData(
int objid, int generation, Pipeline* pipeline)
{
QPDFObjectHandle foreign_stream =
this->foreign_streams[QPDFObjGen(objid, generation)];
foreign_stream.pipeStreamData(pipeline, 0, qpdf_dl_none);
}
void
QPDF::CopiedStreamDataProvider::registerForeignStream(
QPDFObjGen const& local_og, QPDFObjectHandle foreign_stream)
{
this->foreign_streams[local_og] = foreign_stream;
}
QPDF::StringDecrypter::StringDecrypter(QPDF* qpdf, int objid, int gen) :
qpdf(qpdf),
objid(objid),
gen(gen)
{
}
void
QPDF::StringDecrypter::decryptString(std::string& val)
{
qpdf->decryptString(val, objid, gen);
}
std::string const&
QPDF::QPDFVersion()
{
return QPDF::qpdf_version;
}
QPDF::Members::Members() :
provided_password_is_hex_key(false),
encrypted(false),
encryption_initialized(false),
ignore_xref_streams(false),
suppress_warnings(false),
out_stream(&std::cout),
err_stream(&std::cerr),
attempt_recovery(true),
encryption_V(0),
encryption_R(0),
encrypt_metadata(true),
cf_stream(e_none),
cf_string(e_none),
cf_file(e_none),
cached_key_objid(0),
cached_key_generation(0),
pushed_inherited_attributes_to_pages(false),
copied_stream_data_provider(0),
reconstructed_xref(false),
first_xref_item_offset(0),
uncompressed_after_compressed(false)
{
}
QPDF::Members::~Members()
{
}
QPDF::QPDF() :
m(new Members())
{
m->tokenizer.allowEOF();
}
QPDF::~QPDF()
{
// If two objects are mutually referential (through each object
// having an array or dictionary that contains an indirect
// reference to the other), the circular references in the
// PointerHolder objects will prevent the objects from being
// deleted. Walk through all objects in the object cache, which
// is those objects that we read from the file, and break all
// resolved references. At this point, obviously no one is still
// using the QPDF object, but we'll explicitly clear the xref
// table anyway just to prevent any possibility of resolve()
// succeeding. Note that we can't break references like this at
// any time when the QPDF object is active. If we do, the next
// reference will reread the object from the file, which would
// have the effect of undoing any modifications that may have been
// made to any of the objects.
this->m->xref_table.clear();
for (std::map<QPDFObjGen, ObjCache>::iterator iter =
this->m->obj_cache.begin();
iter != this->m->obj_cache.end(); ++iter)
{
QPDFObject::ObjAccessor::releaseResolved(
(*iter).second.object.getPointer());
}
}
void
QPDF::processFile(char const* filename, char const* password)
{
FileInputSource* fi = new FileInputSource();
fi->setFilename(filename);
processInputSource(fi, password);
}
void
QPDF::processFile(char const* description, FILE* filep,
bool close_file, char const* password)
{
FileInputSource* fi = new FileInputSource();
fi->setFile(description, filep, close_file);
processInputSource(fi, password);
}
void
QPDF::processMemoryFile(char const* description,
char const* buf, size_t length,
char const* password)
{
processInputSource(
new BufferInputSource(
description,
new Buffer(QUtil::unsigned_char_pointer(buf), length),
true),
password);
}
void
QPDF::processInputSource(PointerHolder<InputSource> source,
char const* password)
{
this->m->file = source;
parse(password);
}
void
QPDF::setPasswordIsHexKey(bool val)
{
this->m->provided_password_is_hex_key = val;
}
void
QPDF::emptyPDF()
{
processMemoryFile("empty PDF", EMPTY_PDF, strlen(EMPTY_PDF));
}
void
QPDF::setIgnoreXRefStreams(bool val)
{
this->m->ignore_xref_streams = val;
}
void
QPDF::setOutputStreams(std::ostream* out, std::ostream* err)
{
this->m->out_stream = out ? out : &std::cout;
this->m->err_stream = err ? err : &std::cerr;
}
void
QPDF::setSuppressWarnings(bool val)
{
this->m->suppress_warnings = val;
}
void
QPDF::setAttemptRecovery(bool val)
{
this->m->attempt_recovery = val;
}
std::vector<QPDFExc>
QPDF::getWarnings()
{
std::vector<QPDFExc> result = this->m->warnings;
this->m->warnings.clear();
return result;
}
bool
QPDF::findHeader()
{
qpdf_offset_t global_offset = this->m->file->tell();
std::string line = this->m->file->readLine(1024);
char const* p = line.c_str();
if (strncmp(p, "%PDF-", 5) != 0)
{
throw std::logic_error("findHeader is not looking at %PDF-");
}
p += 5;
std::string version;
// Note: The string returned by line.c_str() is always
// null-terminated. The code below never overruns the buffer
// because a null character always short-circuits further
// advancement.
bool valid = QUtil::is_digit(*p);
if (valid)
{
while (QUtil::is_digit(*p))
{
version.append(1, *p++);
}
if ((*p == '.') && QUtil::is_digit(*(p+1)))
{
version.append(1, *p++);
while (QUtil::is_digit(*p))
{
version.append(1, *p++);
}
}
else
{
valid = false;
}
}
if (valid)
{
this->m->pdf_version = version;
if (global_offset != 0)
{
// Empirical evidence strongly suggests that when there is
// leading material prior to the PDF header, all explicit
// offsets in the file are such that 0 points to the
// beginning of the header.
QTC::TC("qpdf", "QPDF global offset");
this->m->file = new OffsetInputSource(this->m->file, global_offset);
}
}
return valid;
}
bool
QPDF::findStartxref()
{
QPDFTokenizer::Token t = readToken(this->m->file);
if (t == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "startxref"))
{
t = readToken(this->m->file);
if (t.getType() == QPDFTokenizer::tt_integer)
{
// Position in front of offset token
this->m->file->seek(this->m->file->getLastOffset(), SEEK_SET);
return true;
}
}
return false;
}
void
QPDF::parse(char const* password)
{
if (password)
{
this->m->provided_password = password;
}
// Find the header anywhere in the first 1024 bytes of the file.
PatternFinder hf(*this, &QPDF::findHeader);
if (! this->m->file->findFirst("%PDF-", 0, 1024, hf))
{
QTC::TC("qpdf", "QPDF not a pdf file");
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", 0, "can't find PDF header"));
// QPDFWriter writes files that usually require at least
// version 1.2 for /FlateDecode
this->m->pdf_version = "1.2";
}
if (atof(this->m->pdf_version.c_str()) < 1.2)
{
this->m->tokenizer.allowPoundAnywhereInName();
}
// PDF spec says %%EOF must be found within the last 1024 bytes of
// the file. We add an extra 30 characters to leave room for the
// startxref stuff.
this->m->file->seek(0, SEEK_END);
qpdf_offset_t end_offset = this->m->file->tell();
qpdf_offset_t start_offset = (end_offset > 1054 ? end_offset - 1054 : 0);
PatternFinder sf(*this, &QPDF::findStartxref);
qpdf_offset_t xref_offset = 0;
if (this->m->file->findLast("startxref", start_offset, 0, sf))
{
xref_offset = QUtil::string_to_ll(
readToken(this->m->file).getValue().c_str());
}
try
{
if (xref_offset == 0)
{
QTC::TC("qpdf", "QPDF can't find startxref");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"can't find startxref");
}
read_xref(xref_offset);
}
catch (QPDFExc& e)
{
if (this->m->attempt_recovery)
{
reconstruct_xref(e);
QTC::TC("qpdf", "QPDF reconstructed xref table");
}
else
{
throw e;
}
}
initializeEncryption();
findAttachmentStreams();
}
void
QPDF::warn(QPDFExc const& e)
{
this->m->warnings.push_back(e);
if (! this->m->suppress_warnings)
{
*this->m->err_stream
<< "WARNING: "
<< this->m->warnings.back().what() << std::endl;
}
}
void
QPDF::setTrailer(QPDFObjectHandle obj)
{
if (this->m->trailer.isInitialized())
{
return;
}
this->m->trailer = obj;
}
void
QPDF::reconstruct_xref(QPDFExc& e)
{
if (this->m->reconstructed_xref)
{
// Avoid xref reconstruction infinite loops. This is getting
// very hard to reproduce because qpdf is throwing many fewer
// exceptions while parsing. Most situations are warnings now.
throw e;
}
this->m->reconstructed_xref = true;
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"file is damaged"));
warn(e);
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"Attempting to reconstruct cross-reference table"));
// Delete all references to type 1 (uncompressed) objects
std::set<QPDFObjGen> to_delete;
for (std::map<QPDFObjGen, QPDFXRefEntry>::iterator iter =
this->m->xref_table.begin();
iter != this->m->xref_table.end(); ++iter)
{
if (((*iter).second).getType() == 1)
{
to_delete.insert((*iter).first);
}
}
for (std::set<QPDFObjGen>::iterator iter = to_delete.begin();
iter != to_delete.end(); ++iter)
{
this->m->xref_table.erase(*iter);
}
this->m->file->seek(0, SEEK_END);
qpdf_offset_t eof = this->m->file->tell();
this->m->file->seek(0, SEEK_SET);
bool in_obj = false;
qpdf_offset_t line_start = 0;
// Don't allow very long tokens here during recovery.
static size_t const MAX_LEN = 100;
while (this->m->file->tell() < eof)
{
this->m->file->findAndSkipNextEOL();
qpdf_offset_t next_line_start = this->m->file->tell();
this->m->file->seek(line_start, SEEK_SET);
QPDFTokenizer::Token t1 = readToken(this->m->file, MAX_LEN);
qpdf_offset_t token_start =
this->m->file->tell() - t1.getValue().length();
if (token_start >= next_line_start)
{
// don't process yet
}
else if (in_obj)
{
if (t1 == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "endobj"))
{
in_obj = false;
}
}
else
{
if (t1.getType() == QPDFTokenizer::tt_integer)
{
QPDFTokenizer::Token t2 =
readToken(this->m->file, MAX_LEN);
QPDFTokenizer::Token t3 =
readToken(this->m->file, MAX_LEN);
if ((t2.getType() == QPDFTokenizer::tt_integer) &&
(t3 == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "obj")))
{
in_obj = true;
int obj = QUtil::string_to_int(t1.getValue().c_str());
int gen = QUtil::string_to_int(t2.getValue().c_str());
insertXrefEntry(obj, 1, token_start, gen, true);
}
}
else if ((! this->m->trailer.isInitialized()) &&
(t1 == QPDFTokenizer::Token(
QPDFTokenizer::tt_word, "trailer")))
{
QPDFObjectHandle t =
readObject(this->m->file, "trailer", 0, 0, false);
if (! t.isDictionary())
{
// Oh well. It was worth a try.
}
else
{
setTrailer(t);
}
}
}
this->m->file->seek(next_line_start, SEEK_SET);
line_start = next_line_start;
}
if (! this->m->trailer.isInitialized())
{
// We could check the last encountered object to see if it was
// an xref stream. If so, we could try to get the trailer
// from there. This may make it possible to recover files
// with bad startxref pointers even when they have object
// streams.
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"unable to find trailer "
"dictionary while recovering damaged file");
}
// We could iterate through the objects looking for streams and
// try to find objects inside of them, but it's probably not worth
// the trouble. Acrobat can't recover files with any errors in an
// xref stream, and this would be a real long shot anyway. If we
// wanted to do anything that involved looking at stream contents,
// we'd also have to call initializeEncryption() here. It's safe
// to call it more than once.
}
void
QPDF::read_xref(qpdf_offset_t xref_offset)
{
std::map<int, int> free_table;
std::set<qpdf_offset_t> visited;
while (xref_offset)
{
visited.insert(xref_offset);
char buf[7];
memset(buf, 0, sizeof(buf));
this->m->file->seek(xref_offset, SEEK_SET);
this->m->file->read(buf, sizeof(buf) - 1);
// The PDF spec says xref must be followed by a line
// terminator, but files exist in the wild where it is
// terminated by arbitrary whitespace.
if ((strncmp(buf, "xref", 4) == 0) &&
QUtil::is_space(buf[4]))
{
QTC::TC("qpdf", "QPDF xref space",
((buf[4] == '\n') ? 0 :
(buf[4] == '\r') ? 1 :
(buf[4] == ' ') ? 2 : 9999));
int skip = 4;
// buf is null-terminated, and QUtil::is_space('\0') is
// false, so this won't overrun.
while (QUtil::is_space(buf[skip]))
{
++skip;
}
xref_offset = read_xrefTable(xref_offset + skip);
}
else
{
xref_offset = read_xrefStream(xref_offset);
}
if (visited.count(xref_offset) != 0)
{
QTC::TC("qpdf", "QPDF xref loop");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"loop detected following xref tables");
}
}
if (! this->m->trailer.isInitialized())
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"unable to find trailer while reading xref");
}
int size = this->m->trailer.getKey("/Size").getIntValue();
int max_obj = 0;
if (! this->m->xref_table.empty())
{
max_obj = (*(this->m->xref_table.rbegin())).first.getObj();
}
if (! this->m->deleted_objects.empty())
{
max_obj = std::max(max_obj, *(this->m->deleted_objects.rbegin()));
}
if (size != max_obj + 1)
{
QTC::TC("qpdf", "QPDF xref size mismatch");
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
std::string("reported number of objects (") +
QUtil::int_to_string(size) +
") inconsistent with actual number of objects (" +
QUtil::int_to_string(max_obj + 1) + ")"));
}
// We no longer need the deleted_objects table, so go ahead and
// clear it out to make sure we never depend on its being set.
this->m->deleted_objects.clear();
}
bool
QPDF::parse_xrefFirst(std::string const& line,
int& obj, int& num, int& bytes)
{
// is_space and is_digit both return false on '\0', so this will
// not overrun the null-terminated buffer.
char const* p = line.c_str();
char const* start = line.c_str();
// Skip zero or more spaces
while (QUtil::is_space(*p))
{
++p;
}
// Require digit
if (! QUtil::is_digit(*p))
{
return false;
}
// Gather digits
std::string obj_str;
while (QUtil::is_digit(*p))
{
obj_str.append(1, *p++);
}
// Require space
if (! QUtil::is_space(*p))
{
return false;
}
// Skip spaces
while (QUtil::is_space(*p))
{
++p;
}
// Require digit
if (! QUtil::is_digit(*p))
{
return false;
}
// Gather digits
std::string num_str;
while (QUtil::is_digit(*p))
{
num_str.append(1, *p++);
}
// Skip any space including line terminators
while (QUtil::is_space(*p))
{
++p;
}
bytes = p - start;
obj = QUtil::string_to_int(obj_str.c_str());
num = QUtil::string_to_int(num_str.c_str());
return true;
}
bool
QPDF::parse_xrefEntry(std::string const& line,
qpdf_offset_t& f1, int& f2, char& type)
{
// is_space and is_digit both return false on '\0', so this will
// not overrun the null-terminated buffer.
char const* p = line.c_str();
// Skip zero or more spaces. There aren't supposed to be any.
bool invalid = false;
while (QUtil::is_space(*p))
{
++p;
QTC::TC("qpdf", "QPDF ignore first space in xref entry");
invalid = true;
}
// Require digit
if (! QUtil::is_digit(*p))
{
return false;
}
// Gather digits
std::string f1_str;
while (QUtil::is_digit(*p))
{
f1_str.append(1, *p++);
}
// Require space
if (! QUtil::is_space(*p))
{
return false;
}
if (QUtil::is_space(*(p+1)))
{
QTC::TC("qpdf", "QPDF ignore first extra space in xref entry");
invalid = true;
}
// Skip spaces
while (QUtil::is_space(*p))
{
++p;
}
// Require digit
if (! QUtil::is_digit(*p))
{
return false;
}
// Gather digits
std::string f2_str;
while (QUtil::is_digit(*p))
{
f2_str.append(1, *p++);
}
// Require space
if (! QUtil::is_space(*p))
{
return false;
}
if (QUtil::is_space(*(p+1)))
{
QTC::TC("qpdf", "QPDF ignore second extra space in xref entry");
invalid = true;
}
// Skip spaces
while (QUtil::is_space(*p))
{
++p;
}
if ((*p == 'f') || (*p == 'n'))
{
type = *p;
}
else
{
return false;
}
if ((f1_str.length() != 10) || (f2_str.length() != 5))
{
QTC::TC("qpdf", "QPDF ignore length error xref entry");
invalid = true;
}
if (invalid)
{
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref table",
this->m->file->getLastOffset(),
"accepting invalid xref table entry"));
}
f1 = QUtil::string_to_ll(f1_str.c_str());
f2 = QUtil::string_to_int(f2_str.c_str());
return true;
}
qpdf_offset_t
QPDF::read_xrefTable(qpdf_offset_t xref_offset)
{
std::vector<QPDFObjGen> deleted_items;
this->m->file->seek(xref_offset, SEEK_SET);
bool done = false;
while (! done)
{
char linebuf[51];
memset(linebuf, 0, sizeof(linebuf));
this->m->file->read(linebuf, sizeof(linebuf) - 1);
std::string line = linebuf;
int obj = 0;
int num = 0;
int bytes = 0;
if (! parse_xrefFirst(line, obj, num, bytes))
{
QTC::TC("qpdf", "QPDF invalid xref");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref table", this->m->file->getLastOffset(),
"xref syntax invalid");
}
this->m->file->seek(this->m->file->getLastOffset() + bytes, SEEK_SET);
for (int i = obj; i < obj + num; ++i)
{
if (i == 0)
{
// This is needed by checkLinearization()
this->m->first_xref_item_offset = this->m->file->tell();
}
std::string xref_entry = this->m->file->readLine(30);
// For xref_table, these will always be small enough to be ints
qpdf_offset_t f1 = 0;
int f2 = 0;
char type = '\0';
if (! parse_xrefEntry(xref_entry, f1, f2, type))
{
QTC::TC("qpdf", "QPDF invalid xref entry");
throw QPDFExc(
qpdf_e_damaged_pdf, this->m->file->getName(),
"xref table", this->m->file->getLastOffset(),
"invalid xref entry (obj=" +
QUtil::int_to_string(i) + ")");
}
if (type == 'f')
{
// Save deleted items until after we've checked the
// XRefStm, if any.
deleted_items.push_back(QPDFObjGen(i, f2));
}
else
{
insertXrefEntry(i, 1, f1, f2);
}
}
qpdf_offset_t pos = this->m->file->tell();
QPDFTokenizer::Token t = readToken(this->m->file);
if (t == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "trailer"))
{
done = true;
}
else
{
this->m->file->seek(pos, SEEK_SET);
}
}
// Set offset to previous xref table if any
QPDFObjectHandle cur_trailer =
readObject(this->m->file, "trailer", 0, 0, false);
if (! cur_trailer.isDictionary())
{
QTC::TC("qpdf", "QPDF missing trailer");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", this->m->file->getLastOffset(),
"expected trailer dictionary");
}
if (! this->m->trailer.isInitialized())
{
setTrailer(cur_trailer);
if (! this->m->trailer.hasKey("/Size"))
{
QTC::TC("qpdf", "QPDF trailer lacks size");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"trailer", this->m->file->getLastOffset(),
"trailer dictionary lacks /Size key");
}
if (! this->m->trailer.getKey("/Size").isInteger())
{
QTC::TC("qpdf", "QPDF trailer size not integer");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"trailer", this->m->file->getLastOffset(),
"/Size key in trailer dictionary is not "
"an integer");
}
}
if (cur_trailer.hasKey("/XRefStm"))
{
if (this->m->ignore_xref_streams)
{
QTC::TC("qpdf", "QPDF ignoring XRefStm in trailer");
}
else
{
if (cur_trailer.getKey("/XRefStm").isInteger())
{
// Read the xref stream but disregard any return value
// -- we'll use our trailer's /Prev key instead of the
// xref stream's.
(void) read_xrefStream(
cur_trailer.getKey("/XRefStm").getIntValue());
}
else
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"invalid /XRefStm");
}
}
}
// Handle any deleted items now that we've read the /XRefStm.
for (std::vector<QPDFObjGen>::iterator iter = deleted_items.begin();
iter != deleted_items.end(); ++iter)
{
QPDFObjGen& og = *iter;
insertXrefEntry(og.getObj(), 0, 0, og.getGen());
}
if (cur_trailer.hasKey("/Prev"))
{
if (! cur_trailer.getKey("/Prev").isInteger())
{
QTC::TC("qpdf", "QPDF trailer prev not integer");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"trailer", this->m->file->getLastOffset(),
"/Prev key in trailer dictionary is not "
"an integer");
}
QTC::TC("qpdf", "QPDF prev key in trailer dictionary");
xref_offset = cur_trailer.getKey("/Prev").getIntValue();
}
else
{
xref_offset = 0;
}
return xref_offset;
}
qpdf_offset_t
QPDF::read_xrefStream(qpdf_offset_t xref_offset)
{
bool found = false;
if (! this->m->ignore_xref_streams)
{
int xobj;
int xgen;
QPDFObjectHandle xref_obj;
try
{
xref_obj = readObjectAtOffset(
false, xref_offset, "xref stream", -1, 0, xobj, xgen);
}
catch (QPDFExc&)
{
// ignore -- report error below
}
if (xref_obj.isInitialized() &&
xref_obj.isStream() &&
xref_obj.getDict().getKey("/Type").isName() &&
xref_obj.getDict().getKey("/Type").getName() == "/XRef")
{
QTC::TC("qpdf", "QPDF found xref stream");
found = true;
xref_offset = processXRefStream(xref_offset, xref_obj);
}
}
if (! found)
{
QTC::TC("qpdf", "QPDF can't find xref");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", xref_offset, "xref not found");
}
return xref_offset;
}
qpdf_offset_t
QPDF::processXRefStream(qpdf_offset_t xref_offset, QPDFObjectHandle& xref_obj)
{
QPDFObjectHandle dict = xref_obj.getDict();
QPDFObjectHandle W_obj = dict.getKey("/W");
QPDFObjectHandle Index_obj = dict.getKey("/Index");
if (! (W_obj.isArray() &&
(W_obj.getArrayNItems() >= 3) &&
W_obj.getArrayItem(0).isInteger() &&
W_obj.getArrayItem(1).isInteger() &&
W_obj.getArrayItem(2).isInteger() &&
dict.getKey("/Size").isInteger() &&
(Index_obj.isArray() || Index_obj.isNull())))
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream does not have"
" proper /W and /Index keys");
}
int W[3];
size_t entry_size = 0;
int max_bytes = sizeof(qpdf_offset_t);
for (int i = 0; i < 3; ++i)
{
W[i] = W_obj.getArrayItem(i).getIntValue();
if (W[i] > max_bytes)
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream's /W contains"
" impossibly large values");
}
entry_size += W[i];
}
if (entry_size == 0)
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream's /W indicates"
" entry size of 0");
}
long long max_num_entries =
static_cast<unsigned long long>(-1) / entry_size;
std::vector<long long> indx;
if (Index_obj.isArray())
{
int n_index = Index_obj.getArrayNItems();
if ((n_index % 2) || (n_index < 2))
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream's /Index has an"
" invalid number of values");
}
for (int i = 0; i < n_index; ++i)
{
if (Index_obj.getArrayItem(i).isInteger())
{
indx.push_back(Index_obj.getArrayItem(i).getIntValue());
}
else
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream's /Index's item " +
QUtil::int_to_string(i) +
" is not an integer");
}
}
QTC::TC("qpdf", "QPDF xref /Index is array",
n_index == 2 ? 0 : 1);
}
else
{
QTC::TC("qpdf", "QPDF xref /Index is null");
long long size = dict.getKey("/Size").getIntValue();
indx.push_back(0);
indx.push_back(size);
}
long long num_entries = 0;
for (unsigned int i = 1; i < indx.size(); i += 2)
{
if (indx.at(i) > max_num_entries - num_entries)
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream claims to contain"
" too many entries: " +
QUtil::int_to_string(indx.at(i)) + " " +
QUtil::int_to_string(max_num_entries) + " " +
QUtil::int_to_string(num_entries));
}
num_entries += indx.at(i);
}
// entry_size and num_entries have both been validated to ensure
// that this multiplication does not cause an overflow.
size_t expected_size = entry_size * num_entries;
PointerHolder<Buffer> bp = xref_obj.getStreamData(qpdf_dl_specialized);
size_t actual_size = bp->getSize();
if (expected_size != actual_size)
{
QPDFExc x(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", xref_offset,
"Cross-reference stream data has the wrong size;"
" expected = " + QUtil::int_to_string(expected_size) +
"; actual = " + QUtil::int_to_string(actual_size));
if (expected_size > actual_size)
{
throw x;
}
else
{
warn(x);
}
}
int cur_chunk = 0;
int chunk_count = 0;
bool saw_first_compressed_object = false;
// Actual size vs. expected size check above ensures that we will
// not overflow any buffers here. We know that entry_size *
// num_entries is equal to the size of the buffer.
unsigned char const* data = bp->getBuffer();
for (int i = 0; i < num_entries; ++i)
{
// Read this entry
unsigned char const* entry = data + (entry_size * i);
qpdf_offset_t fields[3];
unsigned char const* p = entry;
for (int j = 0; j < 3; ++j)
{
fields[j] = 0;
if ((j == 0) && (W[0] == 0))
{
QTC::TC("qpdf", "QPDF default for xref stream field 0");
fields[0] = 1;
}
for (int k = 0; k < W[j]; ++k)
{
fields[j] <<= 8;
fields[j] += static_cast<int>(*p++);
}
}
// Get the object and generation number. The object number is
// based on /Index. The generation number is 0 unless this is
// an uncompressed object record, in which case the generation
// number appears as the third field.
int obj = indx.at(cur_chunk) + chunk_count;
++chunk_count;
if (chunk_count >= indx.at(cur_chunk + 1))
{
cur_chunk += 2;
chunk_count = 0;
}
if (saw_first_compressed_object)
{
if (fields[0] != 2)
{
this->m->uncompressed_after_compressed = true;
}
}
else if (fields[0] == 2)
{
saw_first_compressed_object = true;
}
if (obj == 0)
{
// This is needed by checkLinearization()
this->m->first_xref_item_offset = xref_offset;
}
insertXrefEntry(obj, static_cast<int>(fields[0]),
fields[1], static_cast<int>(fields[2]));
}
if (! this->m->trailer.isInitialized())
{
setTrailer(dict);
}
if (dict.hasKey("/Prev"))
{
if (! dict.getKey("/Prev").isInteger())
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", this->m->file->getLastOffset(),
"/Prev key in xref stream dictionary is not "
"an integer");
}
QTC::TC("qpdf", "QPDF prev key in xref stream dictionary");
xref_offset = dict.getKey("/Prev").getIntValue();
}
else
{
xref_offset = 0;
}
return xref_offset;
}
void
QPDF::insertXrefEntry(int obj, int f0, qpdf_offset_t f1, int f2, bool overwrite)
{
// Populate the xref table in such a way that the first reference
// to an object that we see, which is the one in the latest xref
// table in which it appears, is the one that gets stored. This
// works because we are reading more recent appends before older
// ones. Exception: if overwrite is true, then replace any
// existing object. This is used in xref recovery mode, which
// reads the file from beginning to end.
// If there is already an entry for this object and generation in
// the table, it means that a later xref table has registered this
// object. Disregard this one.
{ // private scope
int gen = (f0 == 2 ? 0 : f2);
QPDFObjGen og(obj, gen);
if (this->m->xref_table.count(og))
{
if (overwrite)
{
QTC::TC("qpdf", "QPDF xref overwrite object");
this->m->xref_table.erase(og);
}
else
{
QTC::TC("qpdf", "QPDF xref reused object");
return;
}
}
if (this->m->deleted_objects.count(obj))
{
QTC::TC("qpdf", "QPDF xref deleted object");
return;
}
}
switch (f0)
{
case 0:
this->m->deleted_objects.insert(obj);
break;
case 1:
// f2 is generation
QTC::TC("qpdf", "QPDF xref gen > 0", ((f2 > 0) ? 1 : 0));
this->m->xref_table[QPDFObjGen(obj, f2)] = QPDFXRefEntry(f0, f1, f2);
break;
case 2:
this->m->xref_table[QPDFObjGen(obj, 0)] = QPDFXRefEntry(f0, f1, f2);
break;
default:
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"xref stream", this->m->file->getLastOffset(),
"unknown xref stream entry type " +
QUtil::int_to_string(f0));
break;
}
}
void
QPDF::showXRefTable()
{
for (std::map<QPDFObjGen, QPDFXRefEntry>::iterator iter =
this->m->xref_table.begin();
iter != this->m->xref_table.end(); ++iter)
{
QPDFObjGen const& og = (*iter).first;
QPDFXRefEntry const& entry = (*iter).second;
*this->m->out_stream << og.getObj() << "/" << og.getGen() << ": ";
switch (entry.getType())
{
case 1:
*this->m->out_stream
<< "uncompressed; offset = " << entry.getOffset();
break;
case 2:
*this->m->out_stream
<< "compressed; stream = "
<< entry.getObjStreamNumber()
<< ", index = " << entry.getObjStreamIndex();
break;
default:
throw std::logic_error("unknown cross-reference table type while"
" showing xref_table");
break;
}
*this->m->out_stream << std::endl;
}
}
size_t
QPDF::getObjectCount()
{
// This method returns the next available indirect object number.
// makeIndirectObject uses it for this purpose.
QPDFObjGen o1(0, 0);
if (! this->m->obj_cache.empty())
{
o1 = (*(this->m->obj_cache.rbegin())).first;
}
QPDFObjGen o2 = (*(this->m->xref_table.rbegin())).first;
QTC::TC("qpdf", "QPDF indirect last obj from xref",
(o2.getObj() > o1.getObj()) ? 1 : 0);
return std::max(o1.getObj(), o2.getObj());
}
std::vector<QPDFObjectHandle>
QPDF::getAllObjects()
{
std::vector<QPDFObjectHandle> result;
for (std::map<QPDFObjGen, QPDFXRefEntry>::iterator iter =
this->m->xref_table.begin();
iter != this->m->xref_table.end(); ++iter)
{
QPDFObjGen const& og = (*iter).first;
result.push_back(QPDFObjectHandle::Factory::newIndirect(
this, og.getObj(), og.getGen()));
}
return result;
}
void
QPDF::setLastObjectDescription(std::string const& description,
int objid, int generation)
{
this->m->last_object_description.clear();
if (! description.empty())
{
this->m->last_object_description += description;
if (objid > 0)
{
this->m->last_object_description += ": ";
}
}
if (objid > 0)
{
this->m->last_object_description += "object " +
QUtil::int_to_string(objid) + " " +
QUtil::int_to_string(generation);
}
}
QPDFObjectHandle
QPDF::readObject(PointerHolder<InputSource> input,
std::string const& description,
int objid, int generation, bool in_object_stream)
{
setLastObjectDescription(description, objid, generation);
qpdf_offset_t offset = input->tell();
bool empty = false;
PointerHolder<StringDecrypter> decrypter_ph;
StringDecrypter* decrypter = 0;
if (this->m->encrypted && (! in_object_stream))
{
decrypter_ph = new StringDecrypter(this, objid, generation);
decrypter = decrypter_ph.getPointer();
}
QPDFObjectHandle object = QPDFObjectHandle::parse(
input, this->m->last_object_description,
this->m->tokenizer, empty, decrypter, this);
if (empty)
{
// Nothing in the PDF spec appears to allow empty objects, but
// they have been encountered in actual PDF files and Adobe
// Reader appears to ignore them.
warn(QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description,
input->getLastOffset(),
"empty object treated as null"));
}
else if (object.isDictionary() && (! in_object_stream))
{
// check for stream
qpdf_offset_t cur_offset = input->tell();
if (readToken(input) ==
QPDFTokenizer::Token(QPDFTokenizer::tt_word, "stream"))
{
// The PDF specification states that the word "stream"
// should be followed by either a carriage return and
// a newline or by a newline alone. It specifically
// disallowed following it by a carriage return alone
// since, in that case, there would be no way to tell
// whether the NL in a CR NL sequence was part of the
// stream data. However, some readers, including
// Adobe reader, accept a carriage return by itself
// when followed by a non-newline character, so that's
// what we do here.
{
char ch;
if (input->read(&ch, 1) == 0)
{
// A premature EOF here will result in some
// other problem that will get reported at
// another time.
}
else if (ch == '\n')
{
// ready to read stream data
QTC::TC("qpdf", "QPDF stream with NL only");
}
else if (ch == '\r')
{
// Read another character
if (input->read(&ch, 1) != 0)
{
if (ch == '\n')
{
// Ready to read stream data
QTC::TC("qpdf", "QPDF stream with CRNL");
}
else
{
// Treat the \r by itself as the
// whitespace after endstream and
// start reading stream data in spite
// of not having seen a newline.
QTC::TC("qpdf", "QPDF stream with CR only");
input->unreadCh(ch);
warn(QPDFExc(
qpdf_e_damaged_pdf,
input->getName(),
this->m->last_object_description,
input->tell(),
"stream keyword followed"
" by carriage return only"));
}
}
}
else
{
QTC::TC("qpdf", "QPDF stream without newline");
if (! QUtil::is_space(ch))
{
QTC::TC("qpdf", "QPDF stream with non-space");
input->unreadCh(ch);
}
warn(QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description,
input->tell(),
"stream keyword not followed"
" by proper line terminator"));
}
}
// Must get offset before accessing any additional
// objects since resolving a previously unresolved
// indirect object will change file position.
qpdf_offset_t stream_offset = input->tell();
size_t length = 0;
try
{
std::map<std::string, QPDFObjectHandle> dict =
object.getDictAsMap();
if (dict.count("/Length") == 0)
{
QTC::TC("qpdf", "QPDF stream without length");
throw QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description, offset,
"stream dictionary lacks /Length key");
}
QPDFObjectHandle length_obj = dict["/Length"];
if (! length_obj.isInteger())
{
QTC::TC("qpdf", "QPDF stream length not integer");
throw QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description, offset,
"/Length key in stream dictionary is not "
"an integer");
}
length = length_obj.getIntValue();
input->seek(stream_offset + length, SEEK_SET);
if (! (readToken(input) ==
QPDFTokenizer::Token(
QPDFTokenizer::tt_word, "endstream")))
{
QTC::TC("qpdf", "QPDF missing endstream");
throw QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description,
input->getLastOffset(),
"expected endstream");
}
}
catch (QPDFExc& e)
{
if (this->m->attempt_recovery)
{
warn(e);
length = recoverStreamLength(
input, objid, generation, stream_offset);
}
else
{
throw e;
}
}
object = QPDFObjectHandle::Factory::newStream(
this, objid, generation, object, stream_offset, length);
}
else
{
input->seek(cur_offset, SEEK_SET);
}
}
// Override last_offset so that it points to the beginning of the
// object we just read
input->setLastOffset(offset);
return object;
}
bool
QPDF::findEndstream()
{
// Find endstream or endobj. Position the input at that token.
QPDFTokenizer::Token t = readToken(this->m->file, 20);
if ((t.getType() == QPDFTokenizer::tt_word) &&
((t.getValue() == "endobj") ||
(t.getValue() == "endstream")))
{
this->m->file->seek(this->m->file->getLastOffset(), SEEK_SET);
return true;
}
return false;
}
size_t
QPDF::recoverStreamLength(PointerHolder<InputSource> input,
int objid, int generation,
qpdf_offset_t stream_offset)
{
// Try to reconstruct stream length by looking for
// endstream or endobj
warn(QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description, stream_offset,
"attempting to recover stream length"));
PatternFinder ef(*this, &QPDF::findEndstream);
size_t length = 0;
if (this->m->file->findFirst("end", stream_offset, 0, ef))
{
length = this->m->file->tell() - stream_offset;
// Reread endstream but, if it was endobj, don't skip that.
QPDFTokenizer::Token t = readToken(this->m->file);
if (t.getValue() == "endobj")
{
this->m->file->seek(this->m->file->getLastOffset(), SEEK_SET);
}
}
if (length)
{
int this_obj_offset = 0;
QPDFObjGen this_obj(0, 0);
// Make sure this is inside this object
for (std::map<QPDFObjGen, QPDFXRefEntry>::iterator iter =
this->m->xref_table.begin();
iter != this->m->xref_table.end(); ++iter)
{
QPDFObjGen const& og = (*iter).first;
QPDFXRefEntry const& entry = (*iter).second;
if (entry.getType() == 1)
{
qpdf_offset_t obj_offset = entry.getOffset();
if ((obj_offset > stream_offset) &&
((this_obj_offset == 0) ||
(this_obj_offset > obj_offset)))
{
this_obj_offset = obj_offset;
this_obj = og;
}
}
}
if (this_obj_offset &&
(this_obj.getObj() == objid) &&
(this_obj.getGen() == generation))
{
// Well, we found endstream\nendobj within the space
// allowed for this object, so we're probably in good
// shape.
}
else
{
QTC::TC("qpdf", "QPDF found wrong endstream in recovery");
}
}
if (length == 0)
{
warn(QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description, stream_offset,
"unable to recover stream data;"
" treating stream as empty"));
}
else
{
warn(QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description, stream_offset,
"recovered stream length: " +
QUtil::int_to_string(length)));
}
QTC::TC("qpdf", "QPDF recovered stream length");
return length;
}
QPDFTokenizer::Token
QPDF::readToken(PointerHolder<InputSource> input, size_t max_len)
{
return this->m->tokenizer.readToken(
input, this->m->last_object_description, true, max_len);
}
QPDFObjectHandle
QPDF::readObjectAtOffset(bool try_recovery,
qpdf_offset_t offset, std::string const& description,
int exp_objid, int exp_generation,
int& objid, int& generation)
{
if (! this->m->attempt_recovery)
{
try_recovery = false;
}
setLastObjectDescription(description, exp_objid, exp_generation);
// Special case: if offset is 0, just return null. Some PDF
// writers, in particular "Mac OS X 10.7.5 Quartz PDFContext", may
// store deleted objects in the xref table as "0000000000 00000
// n", which is not correct, but it won't hurt anything for to
// ignore these.
if (offset == 0)
{
QTC::TC("qpdf", "QPDF bogus 0 offset", 0);
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description, 0,
"object has offset 0"));
return QPDFObjectHandle::newNull();
}
this->m->file->seek(offset, SEEK_SET);
QPDFTokenizer::Token tobjid = readToken(this->m->file);
QPDFTokenizer::Token tgen = readToken(this->m->file);
QPDFTokenizer::Token tobj = readToken(this->m->file);
bool objidok = (tobjid.getType() == QPDFTokenizer::tt_integer);
int genok = (tgen.getType() == QPDFTokenizer::tt_integer);
int objok = (tobj == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "obj"));
QTC::TC("qpdf", "QPDF check objid", objidok ? 1 : 0);
QTC::TC("qpdf", "QPDF check generation", genok ? 1 : 0);
QTC::TC("qpdf", "QPDF check obj", objok ? 1 : 0);
try
{
if (! (objidok && genok && objok))
{
QTC::TC("qpdf", "QPDF expected n n obj");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description, offset,
"expected n n obj");
}
objid = QUtil::string_to_int(tobjid.getValue().c_str());
generation = QUtil::string_to_int(tgen.getValue().c_str());
if (objid == 0)
{
QTC::TC("qpdf", "QPDF object id 0");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description, offset,
"object with ID 0");
}
if ((exp_objid >= 0) &&
(! ((objid == exp_objid) && (generation == exp_generation))))
{
QTC::TC("qpdf", "QPDF err wrong objid/generation");
QPDFExc e(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description, offset,
std::string("expected ") +
QUtil::int_to_string(exp_objid) + " " +
QUtil::int_to_string(exp_generation) + " obj");
if (try_recovery)
{
// Will be retried below
throw e;
}
else
{
// We can try reading the object anyway even if the ID
// doesn't match.
warn(e);
}
}
}
catch (QPDFExc& e)
{
if ((exp_objid >= 0) && try_recovery)
{
// Try again after reconstructing xref table
reconstruct_xref(e);
QPDFObjGen og(exp_objid, exp_generation);
if (this->m->xref_table.count(og) &&
(this->m->xref_table[og].getType() == 1))
{
qpdf_offset_t new_offset = this->m->xref_table[og].getOffset();
QPDFObjectHandle result = readObjectAtOffset(
false, new_offset, description,
exp_objid, exp_generation, objid, generation);
QTC::TC("qpdf", "QPDF recovered in readObjectAtOffset");
return result;
}
else
{
QTC::TC("qpdf", "QPDF object gone after xref reconstruction");
warn(QPDFExc(
qpdf_e_damaged_pdf, this->m->file->getName(),
"", 0,
std::string(
"object " +
QUtil::int_to_string(exp_objid) +
" " +
QUtil::int_to_string(exp_generation) +
" not found in file after regenerating"
" cross reference table")));
return QPDFObjectHandle::newNull();
}
}
else
{
throw e;
}
}
QPDFObjectHandle oh = readObject(
this->m->file, description, objid, generation, false);
if (! (readToken(this->m->file) ==
QPDFTokenizer::Token(QPDFTokenizer::tt_word, "endobj")))
{
QTC::TC("qpdf", "QPDF err expected endobj");
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description,
this->m->file->getLastOffset(),
"expected endobj"));
}
QPDFObjGen og(objid, generation);
if (! this->m->obj_cache.count(og))
{
// Store the object in the cache here so it gets cached
// whether we first know the offset or whether we first know
// the object ID and generation (in which we case we would get
// here through resolve).
// Determine the end offset of this object before and after
// white space. We use these numbers to validate
// linearization hint tables. Offsets and lengths of objects
// may imply the end of an object to be anywhere between these
// values.
qpdf_offset_t end_before_space = this->m->file->tell();
// skip over spaces
while (true)
{
char ch;
if (this->m->file->read(&ch, 1))
{
if (! isspace(static_cast<unsigned char>(ch)))
{
this->m->file->seek(-1, SEEK_CUR);
break;
}
}
else
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description,
this->m->file->tell(),
"EOF after endobj");
}
}
qpdf_offset_t end_after_space = this->m->file->tell();
this->m->obj_cache[og] =
ObjCache(QPDFObjectHandle::ObjAccessor::getObject(oh),
end_before_space, end_after_space);
}
return oh;
}
PointerHolder<QPDFObject>
QPDF::resolve(int objid, int generation)
{
// Check object cache before checking xref table. This allows us
// to insert things into the object cache that don't actually
// exist in the file.
QPDFObjGen og(objid, generation);
if (this->m->resolving.count(og))
{
// This can happen if an object references itself directly or
// indirectly in some key that has to be resolved during
// object parsing, such as stream length.
QTC::TC("qpdf", "QPDF recursion loop in resolve");
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", this->m->file->getLastOffset(),
"loop detected resolving object " +
QUtil::int_to_string(objid) + " " +
QUtil::int_to_string(generation)));
return new QPDF_Null;
}
ResolveRecorder rr(this, og);
// PDF spec says unknown objects resolve to the null object.
if ((! this->m->obj_cache.count(og)) && this->m->xref_table.count(og))
{
QPDFXRefEntry const& entry = this->m->xref_table[og];
try
{
switch (entry.getType())
{
case 1:
{
qpdf_offset_t offset = entry.getOffset();
// Object stored in cache by readObjectAtOffset
int aobjid;
int ageneration;
QPDFObjectHandle oh =
readObjectAtOffset(true, offset, "", objid, generation,
aobjid, ageneration);
}
break;
case 2:
resolveObjectsInStream(entry.getObjStreamNumber());
break;
default:
throw QPDFExc(qpdf_e_damaged_pdf,
this->m->file->getName(), "", 0,
"object " +
QUtil::int_to_string(objid) + "/" +
QUtil::int_to_string(generation) +
" has unexpected xref entry type");
}
}
catch (QPDFExc& e)
{
warn(e);
}
catch (std::exception& e)
{
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(), "", 0,
"object " +
QUtil::int_to_string(objid) + "/" +
QUtil::int_to_string(generation) +
": error reading object: " + e.what()));
}
}
if (this->m->obj_cache.count(og) == 0)
{
QTC::TC("qpdf", "QPDF resolve failure to null");
QPDFObjectHandle oh = QPDFObjectHandle::newNull();
this->m->obj_cache[og] =
ObjCache(QPDFObjectHandle::ObjAccessor::getObject(oh), -1, -1);
}
PointerHolder<QPDFObject> result(this->m->obj_cache[og].object);
if (! result->hasDescription())
{
result->setDescription(
this,
"object " + QUtil::int_to_string(objid) + " " +
QUtil::int_to_string(generation));
}
return result;
}
void
QPDF::resolveObjectsInStream(int obj_stream_number)
{
// Force resolution of object stream
QPDFObjectHandle obj_stream = getObjectByID(obj_stream_number, 0);
if (! obj_stream.isStream())
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description,
this->m->file->getLastOffset(),
"supposed object stream " +
QUtil::int_to_string(obj_stream_number) +
" is not a stream");
}
// For linearization data in the object, use the data from the
// object stream for the objects in the stream.
QPDFObjGen stream_og(obj_stream_number, 0);
qpdf_offset_t end_before_space =
this->m->obj_cache[stream_og].end_before_space;
qpdf_offset_t end_after_space =
this->m->obj_cache[stream_og].end_after_space;
QPDFObjectHandle dict = obj_stream.getDict();
if (! (dict.getKey("/Type").isName() &&
dict.getKey("/Type").getName() == "/ObjStm"))
{
QTC::TC("qpdf", "QPDF ERR object stream with wrong type");
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description,
this->m->file->getLastOffset(),
"supposed object stream " +
QUtil::int_to_string(obj_stream_number) +
" has wrong type");
}
if (! (dict.getKey("/N").isInteger() &&
dict.getKey("/First").isInteger()))
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
this->m->last_object_description,
this->m->file->getLastOffset(),
"object stream " +
QUtil::int_to_string(obj_stream_number) +
" has incorrect keys");
}
int n = dict.getKey("/N").getIntValue();
int first = dict.getKey("/First").getIntValue();
std::map<int, int> offsets;
PointerHolder<Buffer> bp = obj_stream.getStreamData(qpdf_dl_specialized);
PointerHolder<InputSource> input = new BufferInputSource(
this->m->file->getName() +
" object stream " + QUtil::int_to_string(obj_stream_number),
bp.getPointer());
for (int i = 0; i < n; ++i)
{
QPDFTokenizer::Token tnum = readToken(input);
QPDFTokenizer::Token toffset = readToken(input);
if (! ((tnum.getType() == QPDFTokenizer::tt_integer) &&
(toffset.getType() == QPDFTokenizer::tt_integer)))
{
throw QPDFExc(qpdf_e_damaged_pdf, input->getName(),
this->m->last_object_description,
input->getLastOffset(),
"expected integer in object stream header");
}
int num = QUtil::string_to_int(tnum.getValue().c_str());
int offset = QUtil::string_to_ll(toffset.getValue().c_str());
offsets[num] = offset + first;
}
// To avoid having to read the object stream multiple times, store
// all objects that would be found here in the cache. Remember
// that some objects stored here might have been overridden by new
// objects appended to the file, so it is necessary to recheck the
// xref table and only cache what would actually be resolved here.
for (std::map<int, int>::iterator iter = offsets.begin();
iter != offsets.end(); ++iter)
{
int obj = (*iter).first;
QPDFObjGen og(obj, 0);
QPDFXRefEntry const& entry = this->m->xref_table[og];
if ((entry.getType() == 2) &&
(entry.getObjStreamNumber() == obj_stream_number))
{
int offset = (*iter).second;
input->seek(offset, SEEK_SET);
QPDFObjectHandle oh = readObject(input, "", obj, 0, true);
this->m->obj_cache[og] =
ObjCache(QPDFObjectHandle::ObjAccessor::getObject(oh),
end_before_space, end_after_space);
}
else
{
QTC::TC("qpdf", "QPDF not caching overridden objstm object");
}
}
}
QPDFObjectHandle
QPDF::makeIndirectObject(QPDFObjectHandle oh)
{
int max_objid = getObjectCount();
QPDFObjGen next(max_objid + 1, 0);
this->m->obj_cache[next] =
ObjCache(QPDFObjectHandle::ObjAccessor::getObject(oh), -1, -1);
return QPDFObjectHandle::Factory::newIndirect(
this, next.getObj(), next.getGen());
}
QPDFObjectHandle
QPDF::getObjectByObjGen(QPDFObjGen const& og)
{
return getObjectByID(og.getObj(), og.getGen());
}
QPDFObjectHandle
QPDF::getObjectByID(int objid, int generation)
{
return QPDFObjectHandle::Factory::newIndirect(this, objid, generation);
}
void
QPDF::replaceObject(QPDFObjGen const& og, QPDFObjectHandle oh)
{
replaceObject(og.getObj(), og.getGen(), oh);
}
void
QPDF::replaceObject(int objid, int generation, QPDFObjectHandle oh)
{
if (oh.isIndirect())
{
QTC::TC("qpdf", "QPDF replaceObject called with indirect object");
throw std::logic_error(
"QPDF::replaceObject called with indirect object handle");
}
// Force new object to appear in the cache
resolve(objid, generation);
// Replace the object in the object cache
QPDFObjGen og(objid, generation);
this->m->obj_cache[og] =
ObjCache(QPDFObjectHandle::ObjAccessor::getObject(oh), -1, -1);
}
void
QPDF::replaceReserved(QPDFObjectHandle reserved,
QPDFObjectHandle replacement)
{
QTC::TC("qpdf", "QPDF replaceReserved");
reserved.assertReserved();
replaceObject(reserved.getObjGen(), replacement);
}
QPDFObjectHandle
QPDF::copyForeignObject(QPDFObjectHandle foreign)
{
return copyForeignObject(foreign, false);
}
QPDFObjectHandle
QPDF::copyForeignObject(QPDFObjectHandle foreign, bool allow_page)
{
if (! foreign.isIndirect())
{
QTC::TC("qpdf", "QPDF copyForeign direct");
throw std::logic_error(
"QPDF::copyForeign called with direct object handle");
}
QPDF* other = foreign.getOwningQPDF();
if (other == this)
{
QTC::TC("qpdf", "QPDF copyForeign not foreign");
throw std::logic_error(
"QPDF::copyForeign called with object from this QPDF");
}
ObjCopier& obj_copier = this->m->object_copiers[other];
if (! obj_copier.visiting.empty())
{
throw std::logic_error("obj_copier.visiting is not empty"
" at the beginning of copyForeignObject");
}
// Make sure we have an object in this file for every referenced
// object in the old file. obj_copier.object_map maps foreign
// QPDFObjGen to local objects. For everything new that we have
// to copy, the local object will be a reservation, unless it is a
// stream, in which case the local object will already be a
// stream.
reserveObjects(foreign, obj_copier, true);
if (! obj_copier.visiting.empty())
{
throw std::logic_error("obj_copier.visiting is not empty"
" after reserving objects");
}
// Copy any new objects and replace the reservations.
for (std::vector<QPDFObjectHandle>::iterator iter =
obj_copier.to_copy.begin();
iter != obj_copier.to_copy.end(); ++iter)
{
QPDFObjectHandle& to_copy = *iter;
QPDFObjectHandle copy =
replaceForeignIndirectObjects(to_copy, obj_copier, true);
if (! to_copy.isStream())
{
QPDFObjGen og(to_copy.getObjGen());
replaceReserved(obj_copier.object_map[og], copy);
}
}
obj_copier.to_copy.clear();
return obj_copier.object_map[foreign.getObjGen()];
}
void
QPDF::reserveObjects(QPDFObjectHandle foreign, ObjCopier& obj_copier,
bool top)
{
if (foreign.isReserved())
{
throw std::logic_error(
"QPDF: attempting to copy a foreign reserved object");
}
if (foreign.isPagesObject())
{
QTC::TC("qpdf", "QPDF not copying pages object");
return;
}
if ((! top) && foreign.isPageObject())
{
QTC::TC("qpdf", "QPDF not crossing page boundary");
return;
}
if (foreign.isIndirect())
{
QPDFObjGen foreign_og(foreign.getObjGen());
if (obj_copier.visiting.find(foreign_og) != obj_copier.visiting.end())
{
QTC::TC("qpdf", "QPDF loop reserving objects");
return;
}
if (obj_copier.object_map.find(foreign_og) !=
obj_copier.object_map.end())
{
QTC::TC("qpdf", "QPDF already reserved object");
return;
}
QTC::TC("qpdf", "QPDF copy indirect");
obj_copier.visiting.insert(foreign_og);
std::map<QPDFObjGen, QPDFObjectHandle>::iterator mapping =
obj_copier.object_map.find(foreign_og);
if (mapping == obj_copier.object_map.end())
{
obj_copier.to_copy.push_back(foreign);
QPDFObjectHandle reservation;
if (foreign.isStream())
{
reservation = QPDFObjectHandle::newStream(this);
}
else
{
reservation = QPDFObjectHandle::newReserved(this);
}
obj_copier.object_map[foreign_og] = reservation;
}
}
if (foreign.isArray())
{
QTC::TC("qpdf", "QPDF reserve array");
int n = foreign.getArrayNItems();
for (int i = 0; i < n; ++i)
{
reserveObjects(foreign.getArrayItem(i), obj_copier, false);
}
}
else if (foreign.isDictionary())
{
QTC::TC("qpdf", "QPDF reserve dictionary");
std::set<std::string> keys = foreign.getKeys();
for (std::set<std::string>::iterator iter = keys.begin();
iter != keys.end(); ++iter)
{
reserveObjects(foreign.getKey(*iter), obj_copier, false);
}
}
else if (foreign.isStream())
{
QTC::TC("qpdf", "QPDF reserve stream");
reserveObjects(foreign.getDict(), obj_copier, false);
}
if (foreign.isIndirect())
{
QPDFObjGen foreign_og(foreign.getObjGen());
obj_copier.visiting.erase(foreign_og);
}
}
QPDFObjectHandle
QPDF::replaceForeignIndirectObjects(
QPDFObjectHandle foreign, ObjCopier& obj_copier, bool top)
{
QPDFObjectHandle result;
if ((! top) && foreign.isIndirect())
{
QTC::TC("qpdf", "QPDF replace indirect");
QPDFObjGen foreign_og(foreign.getObjGen());
std::map<QPDFObjGen, QPDFObjectHandle>::iterator mapping =
obj_copier.object_map.find(foreign_og);
if (mapping == obj_copier.object_map.end())
{
// This case would occur if this is a reference to a Page
// or Pages object that we didn't traverse into.
QTC::TC("qpdf", "QPDF replace foreign indirect with null");
result = QPDFObjectHandle::newNull();
}
else
{
result = obj_copier.object_map[foreign_og];
}
}
else if (foreign.isArray())
{
QTC::TC("qpdf", "QPDF replace array");
result = QPDFObjectHandle::newArray();
int n = foreign.getArrayNItems();
for (int i = 0; i < n; ++i)
{
result.appendItem(
replaceForeignIndirectObjects(
foreign.getArrayItem(i), obj_copier, false));
}
}
else if (foreign.isDictionary())
{
QTC::TC("qpdf", "QPDF replace dictionary");
result = QPDFObjectHandle::newDictionary();
std::set<std::string> keys = foreign.getKeys();
for (std::set<std::string>::iterator iter = keys.begin();
iter != keys.end(); ++iter)
{
result.replaceKey(
*iter,
replaceForeignIndirectObjects(
foreign.getKey(*iter), obj_copier, false));
}
}
else if (foreign.isStream())
{
QTC::TC("qpdf", "QPDF replace stream");
QPDFObjGen foreign_og(foreign.getObjGen());
result = obj_copier.object_map[foreign_og];
result.assertStream();
QPDFObjectHandle dict = result.getDict();
QPDFObjectHandle old_dict = foreign.getDict();
std::set<std::string> keys = old_dict.getKeys();
for (std::set<std::string>::iterator iter = keys.begin();
iter != keys.end(); ++iter)
{
dict.replaceKey(
*iter,
replaceForeignIndirectObjects(
old_dict.getKey(*iter), obj_copier, false));
}
if (this->m->copied_stream_data_provider == 0)
{
this->m->copied_stream_data_provider =
new CopiedStreamDataProvider();
this->m->copied_streams = this->m->copied_stream_data_provider;
}
QPDFObjGen local_og(result.getObjGen());
this->m->copied_stream_data_provider->registerForeignStream(
local_og, foreign);
result.replaceStreamData(this->m->copied_streams,
dict.getKey("/Filter"),
dict.getKey("/DecodeParms"));
}
else
{
foreign.assertScalar();
result = foreign;
result.makeDirect();
}
if (top && (! result.isStream()) && result.isIndirect())
{
throw std::logic_error("replacement for foreign object is indirect");
}
return result;
}
void
QPDF::swapObjects(QPDFObjGen const& og1, QPDFObjGen const& og2)
{
swapObjects(og1.getObj(), og1.getGen(), og2.getObj(), og2.getGen());
}
void
QPDF::swapObjects(int objid1, int generation1, int objid2, int generation2)
{
// Force objects to be loaded into cache; then swap them in the
// cache.
resolve(objid1, generation1);
resolve(objid2, generation2);
QPDFObjGen og1(objid1, generation1);
QPDFObjGen og2(objid2, generation2);
ObjCache t = this->m->obj_cache[og1];
this->m->obj_cache[og1] = this->m->obj_cache[og2];
this->m->obj_cache[og2] = t;
}
std::string
QPDF::getFilename() const
{
return this->m->file->getName();
}
std::string
QPDF::getPDFVersion() const
{
return this->m->pdf_version;
}
int
QPDF::getExtensionLevel()
{
int result = 0;
QPDFObjectHandle obj = getRoot();
if (obj.hasKey("/Extensions"))
{
obj = obj.getKey("/Extensions");
if (obj.isDictionary() && obj.hasKey("/ADBE"))
{
obj = obj.getKey("/ADBE");
if (obj.isDictionary() && obj.hasKey("/ExtensionLevel"))
{
obj = obj.getKey("/ExtensionLevel");
if (obj.isInteger())
{
result = obj.getIntValue();
}
}
}
}
return result;
}
QPDFObjectHandle
QPDF::getTrailer()
{
return this->m->trailer;
}
QPDFObjectHandle
QPDF::getRoot()
{
QPDFObjectHandle root = this->m->trailer.getKey("/Root");
if (! root.isDictionary())
{
throw QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", this->m->file->getLastOffset(),
"unable to find /Root dictionary");
}
return root;
}
void
QPDF::getObjectStreamData(std::map<int, int>& omap)
{
for (std::map<QPDFObjGen, QPDFXRefEntry>::iterator iter =
this->m->xref_table.begin();
iter != this->m->xref_table.end(); ++iter)
{
QPDFObjGen const& og = (*iter).first;
QPDFXRefEntry const& entry = (*iter).second;
if (entry.getType() == 2)
{
omap[og.getObj()] = entry.getObjStreamNumber();
}
}
}
std::vector<QPDFObjGen>
QPDF::getCompressibleObjGens()
{
// Return a list of objects that are allowed to be in object
// streams. Walk through the objects by traversing the document
// from the root, including a traversal of the pages tree. This
// makes that objects that are on the same page are more likely to
// be in the same object stream, which is slightly more efficient,
// particularly with linearized files. This is better than
// iterating through the xref table since it avoids preserving
// orphaned items.
// Exclude encryption dictionary, if any
QPDFObjectHandle encryption_dict =
this->m->trailer.getKey("/Encrypt");
QPDFObjGen encryption_dict_og = encryption_dict.getObjGen();
std::set<QPDFObjGen> visited;
std::list<QPDFObjectHandle> queue;
queue.push_front(this->m->trailer);
std::vector<QPDFObjGen> result;
while (! queue.empty())
{
QPDFObjectHandle obj = queue.front();
queue.pop_front();
if (obj.isIndirect())
{
QPDFObjGen og = obj.getObjGen();
if (visited.count(og))
{
QTC::TC("qpdf", "QPDF loop detected traversing objects");
continue;
}
if (og == encryption_dict_og)
{
QTC::TC("qpdf", "QPDF exclude encryption dictionary");
}
else if (! obj.isStream())
{
result.push_back(og);
}
visited.insert(og);
}
if (obj.isStream())
{
QPDFObjectHandle dict = obj.getDict();
std::set<std::string> keys = dict.getKeys();
for (std::set<std::string>::reverse_iterator iter = keys.rbegin();
iter != keys.rend(); ++iter)
{
std::string const& key = *iter;
QPDFObjectHandle value = dict.getKey(key);
if (key == "/Length")
{
// omit stream lengths
if (value.isIndirect())
{
QTC::TC("qpdf", "QPDF exclude indirect length");
}
}
else
{
queue.push_front(value);
}
}
}
else if (obj.isDictionary())
{
std::set<std::string> keys = obj.getKeys();
for (std::set<std::string>::reverse_iterator iter = keys.rbegin();
iter != keys.rend(); ++iter)
{
queue.push_front(obj.getKey(*iter));
}
}
else if (obj.isArray())
{
int n = obj.getArrayNItems();
for (int i = 1; i <= n; ++i)
{
queue.push_front(obj.getArrayItem(n - i));
}
}
}
return result;
}
bool
QPDF::pipeStreamData(int objid, int generation,
qpdf_offset_t offset, size_t length,
QPDFObjectHandle stream_dict,
Pipeline* pipeline,
bool suppress_warnings,
bool will_retry)
{
bool success = false;
std::vector<PointerHolder<Pipeline> > to_delete;
if (this->m->encrypted)
{
decryptStream(pipeline, objid, generation, stream_dict, to_delete);
}
try
{
this->m->file->seek(offset, SEEK_SET);
char buf[10240];
while (length > 0)
{
size_t to_read = (sizeof(buf) < length ? sizeof(buf) : length);
size_t len = this->m->file->read(buf, to_read);
if (len == 0)
{
throw QPDFExc(qpdf_e_damaged_pdf,
this->m->file->getName(),
this->m->last_object_description,
this->m->file->getLastOffset(),
"unexpected EOF reading stream data");
}
length -= len;
pipeline->write(QUtil::unsigned_char_pointer(buf), len);
}
pipeline->finish();
success = true;
}
catch (QPDFExc& e)
{
if (! suppress_warnings)
{
warn(e);
}
}
catch (std::exception& e)
{
if (! suppress_warnings)
{
QTC::TC("qpdf", "QPDF decoding error warning");
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", this->m->file->getLastOffset(),
"error decoding stream data for object " +
QUtil::int_to_string(objid) + " " +
QUtil::int_to_string(generation) + ": " + e.what()));
if (will_retry)
{
warn(QPDFExc(qpdf_e_damaged_pdf, this->m->file->getName(),
"", this->m->file->getLastOffset(),
"stream will be re-processed without"
" filtering to avoid data loss"));
}
}
}
if (! success)
{
try
{
pipeline->finish();
}
catch (std::exception&)
{
// ignore
}
}
return success;
}
void
QPDF::findAttachmentStreams()
{
QPDFObjectHandle root = getRoot();
QPDFObjectHandle names = root.getKey("/Names");
if (! names.isDictionary())
{
return;
}
QPDFObjectHandle embeddedFiles = names.getKey("/EmbeddedFiles");
if (! embeddedFiles.isDictionary())
{
return;
}
names = embeddedFiles.getKey("/Names");
if (! names.isArray())
{
return;
}
for (int i = 0; i < names.getArrayNItems(); ++i)
{
QPDFObjectHandle item = names.getArrayItem(i);
if (item.isDictionary() &&
item.getKey("/Type").isName() &&
(item.getKey("/Type").getName() == "/Filespec") &&
item.getKey("/EF").isDictionary() &&
item.getKey("/EF").getKey("/F").isStream())
{
QPDFObjectHandle stream = item.getKey("/EF").getKey("/F");
this->m->attachment_streams.insert(stream.getObjGen());
}
}
}
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