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// -*-C++-*-
#ifndef VEC_MASK_H
#define VEC_MASK_H
#include <cstdlib>
namespace vecmathlib {
template<typename realvec_t>
class mask_t {
typedef typename realvec_t::boolvec_t boolvec_t;
typedef typename realvec_t::intvec_t intvec_t;
static const int size = realvec_t::size;
public:
std::ptrdiff_t imin, imax;
std::ptrdiff_t i;
boolvec_t m;
bool all_m;
public:
// Construct a mask from a boolvec
mask_t(boolvec_t m_): m(m_), all_m(all(m)) {}
// Construct a mask for a particular location i
mask_t(std::ptrdiff_t i_,
std::ptrdiff_t imin_, std::ptrdiff_t imax_, std::ptrdiff_t ioff):
imin(imin_), imax(imax_), i(i_)
{
all_m = i-imin >= 0 && i+size-1-imax < 0;
if (__builtin_expect(all_m, true)) {
m = true;
} else {
m = (! signbit(intvec_t(i - imin) + intvec_t::iota()) &&
signbit(intvec_t(i + size-1 - imax) + intvec_t::iota()));
}
}
// Construct a mask for a loop starting at imin, aligned down
mask_t(std::ptrdiff_t imin_, std::ptrdiff_t imax_, std::ptrdiff_t ioff):
mask_t(imin_ - (ioff + imin_) % size, imin_, imax_, ioff)
{
}
// Get current index
std::ptrdiff_t index() const { return i; }
// Looping condition
operator bool() const { return i<imax; }
// Loop stepper
void operator++()
{
i += size;
all_m = i + size-1 - imax < 0;
if (__builtin_expect(all_m, true)) {
m = true;
} else {
m = signbit(intvec_t(i + size-1 - imax) + intvec_t::iota());
}
}
};
} // namespace vecmathlib
#endif // #ifndef VEC_MASK_H
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