Rewrite fix-qdf in C++

Jay Berkenbilt
1 parent a44b5a34
Showing 7 changed files with 533 additions and 401 deletions
ChangeLog
make/installwin.mk
make/libtool.mk
manual/qpdf-manual.xml
qpdf/build.mk
qpdf/fix-qdf
qpdf/fix-qdf.cc
 2020-01-14  Jay Berkenbilt  <ejb@ql.org>
+	* Rewrite fix-qdf in C++. This means fix-qdf is a proper
+	executable now, and there is no longer a runtime requirement on
+	perl.
+
 	* Add QUtil::call_main_from_wmain, a helper function that can be
 	called in the body of wmain to convert UTF-16 arguments to UTF-8
 	arguments and then call another main function.
@@ -14,7 +14,7 @@ installwin: all
 	perl copy_dlls libqpdf/$(OUTPUT_DIR)/qpdf*.dll $(DEST)/bin $(OBJDUMP) $(WINDOWS_WORDSIZE)
 	cp qpdf/$(OUTPUT_DIR)/qpdf.exe $(DEST)/bin
 	cp zlib-flate/$(OUTPUT_DIR)/zlib-flate.exe $(DEST)/bin
-	cp qpdf/fix-qdf $(DEST)/bin
+	cp qpdf/$(OUTPUT_DIR)/fix-qdf.exe $(DEST)/bin
 	cp include/qpdf/*.h $(DEST)/include/qpdf
 	cp include/qpdf/*.hh $(DEST)/include/qpdf
 	cp doc/stylesheet.css $(DEST)/doc
@@ -122,7 +122,9 @@ install: all
 	$(LIBTOOL) --mode=install ./install-sh \
 		zlib-flate/$(OUTPUT_DIR)/zlib-flate \
 		$(DESTDIR)$(bindir)/zlib-flate
-	./install-sh -m 0755 qpdf/fix-qdf $(DESTDIR)$(bindir)
+	$(LIBTOOL) --mode=install ./install-sh \
+		qpdf/$(OUTPUT_DIR)/fix-qdf \
+		$(DESTDIR)$(bindir)/fix-qdf
 	./install-sh -m 0644 include/qpdf/*.h $(DESTDIR)$(includedir)/qpdf
 	./install-sh -m 0644 include/qpdf/*.hh $(DESTDIR)$(includedir)/qpdf
 	./install-sh -m 0644 doc/stylesheet.css $(DESTDIR)$(docdir)
@@ -150,7 +150,8 @@
       <para>
        perl version 5.8 or newer:
        <ulink url="http://www.perl.org/">http://www.perl.org/</ulink>;
-       required for <command>fix-qdf</command> and the test suite.
+       required for running the test suite. Starting with qpdf version
+       9.1.1, perl is no longer required at runtime.
       </para>
      </listitem>
      <listitem>
@@ -473,6 +474,13 @@ make
     <itemizedlist>
      <listitem>
       <para>
+       Starting in qpdf version 9.1.1, qpdf no longer has a runtime
+       dependency on perl. This is because fix-qdf was rewritten in
+       C++. However, qpdf still has a build-time dependency on perl.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
        Make sure you are getting the intended behavior with regard to
        crypto providers. Read <xref linkend="ref.crypto.build"/> for
        details.
 BINS_qpdf = \
     qpdf \
+    fix-qdf \
     pdf_from_scratch \
     test_driver \
     test_large_file \
@@ -24,10 +25,13 @@ TC_SRCS_qpdf = $(wildcard libqpdf/*.cc) $(wildcard qpdf/*.cc)
 XCXXFLAGS_qpdf_qpdf := $(WINDOWS_WMAIN_COMPILE)
 XLDFLAGS_qpdf_qpdf := $(WINDOWS_WMAIN_LINK)
+XLINK_FLAGS_qpdf_qpdf := $(WINDOWS_WMAIN_XLINK_FLAGS)
 XCXXFLAGS_qpdf_test_unicode_filenames := $(WINDOWS_WMAIN_COMPILE)
 XLDFLAGS_qpdf_test_unicode_filenames := $(WINDOWS_WMAIN_LINK)
-XLINK_FLAGS_qpdf_qpdf := $(WINDOWS_WMAIN_XLINK_FLAGS)
 XLINK_FLAGS_qpdf_test_unicode_filenames := $(WINDOWS_WMAIN_XLINK_FLAGS)
+XCXXFLAGS_qpdf_fix-qdf := $(WINDOWS_WMAIN_COMPILE)
+XLDFLAGS_qpdf_fix-qdf := $(WINDOWS_WMAIN_LINK)
+XLINK_FLAGS_qpdf_fix-qdf := $(WINDOWS_WMAIN_XLINK_FLAGS)
 $(foreach B,$(BINS_qpdf),$(eval \
   OBJS_$(B) = $(call src_to_obj,qpdf/$(B).cc)))
-#!/usr/bin/env perl
-
-require 5.008_001;
-use warnings;
-use strict;
-use File::Basename;
-
-my $whoami = basename($0);
-my $dirname = dirname($0);
-
-if ((@ARGV == 1) && ($ARGV[0] eq '--version'))
-{
-    exec "$dirname/qpdf", '--version';
-    exit 2;
-}
-
-my $offset = 0;
-my $last_offset = 0;
-
-my $file = shift(@ARGV);
-if (defined $file)
-{
-    open(F, "<$file") or die "$whoami: can't open $file: $!\n";
-}
-else
-{
-    $file = 'stdin';
-    open(F, "<&STDIN") or die "$whoami: can't dup stdin: $!\n";
-}
-binmode F;
-binmode STDOUT;
-
-my $line = get_line();
-if (! ((defined $line) && ($line =~ m/^%PDF-1\.\d+\b/)))
-{
-    die "$whoami: $file: not a pdf file\n";
-}
-print $line;
-$line = get_line();
-die "$whoami: $file: premature EOF\n" unless defined $line;
-print $line;
-$line = get_line();
-if (! ((defined $line) && ($line =~ m/^%QDF-1.\d+\b/)))
-{
-    die "$whoami: $file: not a qdf file\n";
-}
-print $line;
-
-my $last_obj = 0;
-my @xref = ();
-
-my $stream_start = 0;
-my $stream_length = 0;
-my $xref_offset = 0;
-my $xref_f1_nbytes = 0;
-my $xref_f2_nbytes = 0;
-my $xref_size = 0;
-
-my $cur_state = 0;
-my $st_top = ++$cur_state;
-my $st_in_obj = ++$cur_state;
-my $st_in_stream = ++$cur_state;
-my $st_after_stream = ++$cur_state;
-my $st_in_ostream_dict = ++$cur_state;
-my $st_in_ostream_offsets = ++$cur_state;
-my $st_in_ostream_outer = ++$cur_state;
-my $st_in_ostream_obj = ++$cur_state;
-my $st_in_xref_stream_dict = ++$cur_state;
-my $st_in_length = ++$cur_state;
-my $st_at_xref = ++$cur_state;
-my $st_before_trailer = ++$cur_state;
-my $st_in_trailer = ++$cur_state;
-my $st_done = ++$cur_state;
-
-my @ostream = ();
-my @ostream_offsets = ();
-my @ostream_discarded = ();
-my $ostream_idx = 0;
-my $ostream_id = 0;
-my $ostream_extends = "";
-
-my $state = $st_top;
-while (defined($line = get_line()))
-{
-    if ($state == $st_top)
-    {
-	if ($line =~ m/^(\d+) 0 obj$/)
-	{
-	    check_obj_id($1);
-	    $state = $st_in_obj;
-	}
-	elsif ($line =~ m/^xref$/)
-	{
-	    $xref_offset = $last_offset;
-	    $state = $st_at_xref;
-	}
-	print $line;
-    }
-    elsif ($state == $st_in_obj)
-    {
-	print $line;
-	if ($line =~ m/^stream$/)
-	{
-	    $state = $st_in_stream;
-	    $stream_start = $offset;
-	}
-	elsif ($line =~ m/^endobj$/)
-	{
-	    $state = $st_top;
-	}
-	elsif ($line =~ m,/Type /ObjStm,)
-	{
-	    $state = $st_in_ostream_dict;
-	    $ostream_id = $last_obj;
-	}
-	elsif ($line =~ m,/Type /XRef,)
-	{
-	    $xref_offset = $xref[-1][1];
-	    $xref_f1_nbytes = 0;
-	    my $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.
-            my $max_objects = 1;
-            foreach my $e (@xref)
-            {
-                my ($type, $f1, $f2) = @$e;
-                if ((defined $f2) && ($f2 > $max_objects))
-                {
-                    $max_objects = $f2;
-                }
-            }
-            while ($max_objects)
-            {
-                $max_objects >>=8;
-                ++$xref_f2_nbytes;
-            }
-	    my $esize = 1 + $xref_f1_nbytes + $xref_f2_nbytes;
-	    $xref_size = 1 + @xref;
-	    my $length = $xref_size * $esize;
-	    print "  /Length $length\n";
-	    print "  /W [ 1 $xref_f1_nbytes $xref_f2_nbytes ]\n";
-	    $state = $st_in_xref_stream_dict;
-	}
-    }
-    elsif ($state == $st_in_ostream_dict)
-    {
-	if ($line =~ m/^stream/)
-	{
-	    $state = $st_in_ostream_offsets;
-	}
-	else
-	{
-	    push(@ostream_discarded, $line);
-	    if ($line =~ m,/Extends (\d+ 0 R),)
-	    {
-		$ostream_extends = $1;
-	    }
-	}
-	# discard line
-    }
-    elsif ($state == $st_in_ostream_offsets)
-    {
-	if ($line =~ m/^\%\% Object stream: object (\d+)/)
-	{
-	    check_obj_id($1);
-	    $stream_start = $last_offset;
-	    $state = $st_in_ostream_outer;
-	    push(@ostream, $line);
-	}
-	else
-	{
-	    push(@ostream_discarded, $line);
-	}
-	# discard line
-    }
-    elsif ($state == $st_in_ostream_outer)
-    {
-	adjust_ostream_xref();
-	push(@ostream_offsets, $last_offset - $stream_start);
-	$state = $st_in_ostream_obj;
-	push(@ostream, $line);
-    }
-    elsif ($state == $st_in_ostream_obj)
-    {
-	push(@ostream, $line);
-	if ($line =~ m/^\%\% Object stream: object (\d+)/)
-	{
-	    check_obj_id($1);
-	    $state = $st_in_ostream_outer;
-	}
-	elsif ($line =~ m/^endstream/)
-	{
-	    $stream_length = $last_offset - $stream_start;
-	    write_ostream();
-	    $state = $st_in_obj;
-	}
-    }
-    elsif ($state == $st_in_xref_stream_dict)
-    {
-	if ($line =~ m,/(Length|W) ,)
-	{
-	    # already printed
-	}
-	elsif ($line =~ m,/Size ,)
-	{
-	    my $size = 1 + @xref;
-	    print "  /Size $xref_size\n";
-	}
-	else
-	{
-	    print $line;
-	}
-	if ($line =~ m/^stream\n/)
-	{
-	    my $pack = "(C C$xref_f1_nbytes C$xref_f2_nbytes)";
-	    print pack($pack, 0, 0, 0);
-	    foreach my $x (@xref)
-	    {
-		my ($type, $f1, $f2) = @$x;
-		$f2 = 0 unless defined $f2;
-                my @f1 = ();
-                my @f2 = ();
-                foreach my $d ([\@f1, $f1, $xref_f1_nbytes],
-                               [\@f2, $f2, $xref_f2_nbytes])
-                {
-                    my ($fa, $f, $nbytes) = @$d;
-                    for (my $i = 0; $i < $nbytes; ++$i)
-                    {
-                        unshift(@$fa, $f & 0xff);
-                        $f >>= 8;
-                    }
-                }
-		print pack($pack, $type, @f1, @f2);
-	    }
-	    print "\nendstream\nendobj\n\n";
-	    print "startxref\n$xref_offset\n\%\%EOF\n";
-	    $state = $st_done;
-	}
-    }
-    elsif ($state == $st_in_stream)
-    {
-	if ($line =~ m/^endstream$/)
-	{
-	    $stream_length = $last_offset - $stream_start;
-	    $state = $st_after_stream;
-	}
-	print $line;
-    }
-    elsif ($state == $st_after_stream)
-    {
-	if ($line =~ m/^\%QDF: ignore_newline$/)
-	{
-	    --$stream_length;
-	}
-	elsif ($line =~ m/^(\d+) 0 obj$/)
-	{
-	    check_obj_id($1);
-	    $state = $st_in_length;
-	}
-	print $line;
-    }
-    elsif ($state == $st_in_length)
-    {
-	if ($line !~ m/^\d+$/)
-	{
-	    die "$file:$.: expected integer\n";
-	}
-	my $new = "$stream_length\n";
-	$offset -= length($line);
-	$offset += length($new);
-	print $new;
-	$state = $st_top;
-    }
-    elsif ($state == $st_at_xref)
-    {
-	my $n = scalar(@xref);
-	print "0 ", $n+1, "\n0000000000 65535 f \n";
-	for (@xref)
-	{
-	    my ($type, $f1, $f2) = @$_;
-	    printf("%010d 00000 n \n", $f1);
-	}
-	$state = $st_before_trailer;
-    }
-    elsif ($state == $st_before_trailer)
-    {
-	if ($line =~ m/^trailer <</)
-	{
-	    print $line;
-	    $state = $st_in_trailer;
-	}
-	# no output
-    }
-    elsif ($state == $st_in_trailer)
-    {
-	if ($line =~ m/^  \/Size \d+$/)
-	{
-	    print "  /Size ", scalar(@xref) + 1, "\n";
-	}
-	else
-	{
-	    print $line;
-	}
-	if ($line =~ m/^>>$/)
-	{
-	    print "startxref\n$xref_offset\n\%\%EOF\n";
-	    $state = $st_done;
-	}
-    }
-    elsif ($state == $st_done)
-    {
-	# ignore
-    }
-}
-
-die "$whoami: $file: premature EOF\n" unless $state == $st_done;
-
-sub get_line
-{
-    my $line = scalar(<F>);
-    if (defined $line)
-    {
-	$last_offset = $offset;
-	$offset += length($line);
-    }
-    $line;
-}
-
-sub check_obj_id
-{
-    my $cur_obj = shift;
-    if ($cur_obj != $last_obj + 1)
-    {
-	die "$file:$.: expected object ", $last_obj + 1, "\n";
-    }
-    $last_obj = $cur_obj;
-    push(@xref, [1, $last_offset]);
-}
-
-sub adjust_ostream_xref
-{
-    pop(@xref);
-    push(@xref, [2, $ostream_id, $ostream_idx++]);
-}
-
-sub write_ostream
-{
-    my $first = $ostream_offsets[0];
-    my $onum = $ostream_id;
-    my $offsets = "";
-    my $n = scalar(@ostream_offsets);
-    for (@ostream_offsets)
-    {
-	$_ -= $first;
-	++$onum;
-	$offsets .= "$onum $_\n";
-    }
-    my $offset_adjust = length($offsets);
-    $first += length($offsets);
-    $stream_length += length($offsets);
-    my $dict_data = "";
-    $dict_data .= "  /Length $stream_length\n";
-    $dict_data .= "  /N $n\n";
-    $dict_data .= "  /First $first\n";
-    if ($ostream_extends)
-    {
-	$dict_data .= "  /Extends $ostream_extends\n";
-    }
-    $dict_data .= ">>\n";
-    $offset_adjust += length($dict_data);
-    print $dict_data;
-    print "stream\n";
-    print $offsets;
-    foreach (@ostream)
-    {
-	print $_;
-    }
-
-    for (@ostream_discarded)
-    {
-	$offset -= length($_);
-    }
-    $offset += $offset_adjust;
-
-    $ostream_idx = 0;
-    $ostream_id = 0;
-    @ostream = ();
-    @ostream_offsets = ();
-    @ostream_discarded = ();
-    $ostream_extends = "";
-}
+#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