Avoid overflowing conversion from double to sal_Int32

...by clamping the value to the sal_Int32 range.  An alternative would be to
instead print nAdjustment as a real value (which the PDF standard apparently
supports, without giving limits to such real values), as had been implemented at
<https://gerrit.libreoffice.org/#/c/74543/1>, but that was deemed unnecessarily
complex, as no sane document should require nAdjustment values outside the
sal_Int32 range.

`--convert-to pdf caolan/drawinglayer_emfphelperdata_heap_use_after_free.sample`
(from the crashtestdata files) has cases where

  double fAdvance = aThisPos.X() - aPrevPos.X();

gets rather large (whether or not that's faithful to the input document, or a
consequence of an earlier import error), so failed with

> vcl/source/gdi/pdfwriter_impl.cxx:6078:66: runtime error: -5.83192e+09 is outside the range of representable values of type 'int'
>  #0 in vcl::PDFWriterImpl::drawHorizontalGlyphs(std::__debug::vector<vcl::PDFWriterImpl::PDFGlyph, std::allocator<vcl::PDFWriterImpl::PDFGlyph> > const&, rtl::OStringBuffer&, Point const&, bool, double, double, double, int, int) at vcl/source/gdi/pdfwriter_impl.cxx:6078:66
>  #1 in vcl::PDFWriterImpl::drawLayout(SalLayout&, rtl::OUString const&, bool) at vcl/source/gdi/pdfwriter_impl.cxx:6404:17
>  #2 in vcl::PDFWriterImpl::drawTextArray(Point const&, rtl::OUString const&, long const*, int, int) at vcl/source/gdi/pdfwriter_impl.cxx:6621:9
>  #3 in vcl::PDFWriter::DrawTextArray(Point const&, rtl::OUString const&, long const*, int, int) at vcl/source/gdi/pdfwriter.cxx:87:22
>  #4 in vcl::PDFWriterImpl::playMetafile(GDIMetaFile const&, vcl::PDFExtOutDevData*, vcl::PDFWriter::PlayMetafileContext const&, VirtualDevice*) at vcl/source/gdi/pdfwriter_impl2.cxx:878:34
[...]

In the original compuation of sal_Int32 nAdjustment, the "+ 0.5" was presumably
intended to round to the nearest integer, even though it would have rounded
towards zero for negative values (as conversion to integer truncates).  So use
std::round to always round to the nearest integer, including for negative
values.

Change-Id: Ie3ddbb66421f47417c6d9ae096f2207a29aca4a4
Reviewed-on: https://gerrit.libreoffice.org/74543
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

0 files changed, 0 insertions, 0 deletions