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Improve thread-safety structures from review

This commit is contained in:
Simon Giraudot 2020-09-29 15:56:13 +02:00
parent 2e56893cf0
commit 3e0fde9683
1 changed files with 42 additions and 45 deletions
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87
Poisson_surface_reconstruction_3/include/CGAL/Poisson_reconstruction_function.h
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@ -225,18 +225,33 @@ private:
std::array<double, 9> m_bary;
public:
Cached_bary_coord() : m_state (UNINITIALIZED) { }
Cached_bary_coord(const Cached_bary_coord& other)
: m_state (other.m_state.load()) // not atomic
{ }
Cached_bary_coord& operator= (const Cached_bary_coord& other)
// Copy operator to satisfy vector, shouldn't be used
Cached_bary_coord(const Cached_bary_coord&)
{
m_state.store (other.m_state.load()); // not atomic
CGAL_error();
}
Cache_state exchange_state(const Cache_state& s) { return m_state.exchange(s); }
Cache_state get_state() { return m_state; }
void set_state(const Cache_state& s) { m_state = s; }
bool is_initialized()
{
Cache_state s = m_state;
if (s == UNINITIALIZED)
{
// If the following line successfully replaces UNINITIALIZED
// by BUSY, then the current thread in charge of initialization
if (m_state.compare_exchange_weak(s, BUSY))
return false;
}
// Otherwise, either the thread is BUSY by another thread, or
// it's already INITIALIZED. Either way, we way until it's INITIALIZED
else
while (m_state != INITIALIZED) { }
// At this point, it's always INITIALIZED
return true;
}
void set_initialized() { m_state = INITIALIZED; }
const double& operator[] (const std::size_t& idx) const { return m_bary[idx]; }
double& operator[] (const std::size_t& idx) { return m_bary[idx]; }
@ -250,14 +265,10 @@ private:
public:
Cell_hint() : m_cell(nullptr) { }
Cell_hint(const Cell_hint& other)
: m_cell (other.m_cell.load()) // not atomic
{ }
Cell_hint& operator= (const Cell_hint& other)
{
m_cell.store (other.m_cell.load()); // not atomic
}
// Poisson_reconstruction_function should be copyable, although we
// don't need to copy that
Cell_hint(const Cell_hint&) : m_cell(nullptr) { }
Cell_handle get() const
{
@ -688,43 +699,29 @@ public:
void initialize_matrix_entry(Cell_handle ch) const
{
Cached_bary_coord& bary = (*m_bary)[ch->info()];
Cache_state s = bary.exchange_state(BUSY);
// If the cache was already initialized, then let's just restore
// the value
if (s == INITIALIZED)
bary.set_state (INITIALIZED);
if (bary.is_initialized())
return;
// If the cache was uninitialized, this thread is in charge of
// initializing it
else if (s == UNINITIALIZED)
{
const Point& pa = ch->vertex(0)->point();
const Point& pb = ch->vertex(1)->point();
const Point& pc = ch->vertex(2)->point();
const Point& pd = ch->vertex(3)->point();
const Point& pa = ch->vertex(0)->point();
const Point& pb = ch->vertex(1)->point();
const Point& pc = ch->vertex(2)->point();
const Point& pd = ch->vertex(3)->point();
Vector va = pa - pd;
Vector vb = pb - pd;
Vector vc = pc - pd;
Vector va = pa - pd;
Vector vb = pb - pd;
Vector vc = pc - pd;
internal::invert(va.x(), va.y(), va.z(),
vb.x(), vb.y(), vb.z(),
vc.x(), vc.y(), vc.z(),
bary[0],bary[1],bary[2],
bary[3],bary[4],bary[5],
bary[6],bary[7],bary[8]);
internal::invert(va.x(), va.y(), va.z(),
vb.x(), vb.y(), vb.z(),
vc.x(), vc.y(), vc.z(),
bary[0],bary[1],bary[2],
bary[3],bary[4],bary[5],
bary[6],bary[7],bary[8]);
bary.set_state (INITIALIZED);
}
// Else, the cache is busy, let's just wait for it to be
// initialized
else
{
CGAL_assertion (s == BUSY);
while (bary.get_state() != INITIALIZED) { }
}
bary.set_initialized();
}
/// \endcond