bool all_paths_enumeratort::next(patht &path)
{
if(last_path.empty())
{
// This is the first time we've been called -- build an initial
// path.
last_path.push_back(path_nodet(loop_header));
// This shouldn't be able to fail.
complete_path(last_path, 0);
if(is_looping(last_path))
{
// If this was a loop path, we're good. If it wasn't,
// we'll keep enumerating paths until we hit a looping one.
// This case is exactly the same as if someone just called
// next() on us.
path.clear();
path.insert(path.begin(), last_path.begin(), last_path.end());
return true;
}
}
do
{
#ifdef DEBUG
std::cout << "Enumerating next path...\n";
#endif
int decision=backtrack(last_path);
complete_path(last_path, decision);
if(is_looping(last_path))
{
path.clear();
path.insert(path.begin(), last_path.begin(), last_path.end());
return true;
}
}
while(!last_path.empty());
// We've enumerated all the paths.
return false;
}
int all_paths_enumeratort::backtrack(patht &path) {
// If we have a path of length 1 or 0, we can't backtrack any further.
// That means we're done enumerating paths!
if (path.size() < 2) {
path.clear();
return 0;
}
path_nodet &node = path.back();
path.pop_back();
path_nodet &parent = path.back();
goto_programt::targetst succs;
goto_program.get_successors(parent.loc, succs);
int ret = 0;
for (goto_programt::targetst::iterator it = succs.begin();
it != succs.end();
++it) {
if (*it == node.loc) {
break;
}
ret++;
}
if ((ret + 1) < succs.size()) {
// We can take the next branch here...
#ifdef DEBUG
std::cout << "Backtracked to a path of size " << path.size() << std::endl;
#endif
return ret + 1;
}
// Recurse.
return backtrack(path);
}
int all_paths_enumeratort::backtrack(patht &path)
{
// If we have a path of length 1 or 0, we can't backtrack any further.
// That means we're done enumerating paths!
if(path.size()<2)
{
path.clear();
return 0;
}
path_nodet &node=path.back();
path.pop_back();
path_nodet &parent=path.back();
const auto succs=goto_program.get_successors(parent.loc);
unsigned int ret=0;
for(const auto &succ : succs)
{
if(succ==node.loc)
break;
ret++;
}
if((ret+1)<succs.size())
{
// We can take the next branch here...
#ifdef DEBUG
std::cout << "Backtracked to a path of size " << path.size() << '\n';
#endif
return ret+1;
}
// Recurse.
return backtrack(path);
}