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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 = (!isignbit(intvec_t(i - imin) + intvec_t::iota()) &&
isignbit(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)
: imin(imin_), imax(imax_), i(imin_ - (ioff + imin_) % size) {
all_m = i - imin >= 0 && i + size - 1 - imax < 0;
if (__builtin_expect(all_m, true)) {
m = true;
} else {
m = (!isignbit(intvec_t(i - imin) + intvec_t::iota()) &&
isignbit(intvec_t(i + size - 1 - imax) + intvec_t::iota()));
}
}
// 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 = isignbit(intvec_t(i + size - 1 - imax) + intvec_t::iota());
}
}
};
} // namespace vecmathlib
#endif // #ifndef VEC_MASK_H
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