empty polygon triggers seg fault

[markghayden]

It seems a set of polygons which ends in an empty polygon triggers a segmentation violation. Please see attached program and output from Valgrind below.

This was tested with Clipper 2 v1.2.0 on Debian Linux.

make -w -k -j8 make: Entering directory '/home/mhayden/plotter/plotter/clipper' g++ -g -O2 -std=c++17 -I/home/mhayden/plotter/toolchain/clipper2/release/linux/Clipper2/include clipper_test.cpp /home/mhayden/plotter/toolchain/clipper2/release/linux/Clipper2/lib/libclipper2.a -o test valgrind ./test ==44300== Memcheck, a memory error detector ==44300== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==44300== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info ==44300== Command: ./test ==44300== len=55 len=48 len=14 len=58 polygons=1 len=25 ==44300== Invalid write of size 8 ==44300== at 0x1102BC: Clipper2Lib::ClipperBase::AddPaths(std::vector<std::vector<Clipper2Lib::Point<long>, std::allocator<Clipper2Lib::Point<long> > >, std::allocator<std::vector<Clipper2Lib::Point<long>, std::allocator<Clipper2Lib::Point<long> > > > > const&, Clipper2Lib::PathType, bool) (clipper.engine.cpp:597) ==44300== by 0x1096FF: AddSubject (clipper.engine.h:446) ==44300== by 0x1096FF: main (clipper_test.cpp:216) ==44300== Address 0x4cb3b70 is 16 bytes after a block of size 7,008 in arena "client" ==44300==
clipper_test.zip