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rngxx/src/rng/crand.cpp

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#include <bit>
#include <climits>
#include <rng.h>
#include <mem.h>
#include <rng/crand.h>
#include "crand.h"
namespace rng
{
void crand::_deleter::delete_object(_opaque** state) { _jr_free(reinterpret_cast<jr_state*>(*state)); *state = nullptr; }
crand::crand(_opaque* raw) :_state(mem::aligned_ptr<_opaque, _deleter>(raw)){}
crand::crand(u64 seed) : crand(reinterpret_cast<_opaque*>(_jr_new(seed))){}
crand::crand() : crand(0xabad1dea){}
i64 crand::_sample_raw() { return _jr_proc(reinterpret_cast<jr_state*>(_state.get_ptr())); }
//TODO: properly implemet this f64 crand::_sample() { return (f64)std::bit_cast<u64>(_sample_raw()) / (f64)UINT64_MAX; }
// Overrides //
u64 crand::next_u64() { return std::bit_cast<u64>(_sample_raw()); }
//TODO: Implementing next_i64(i64 max) should be trivial. the man page for drand48 shows its output range, just map that range to `0..=max`
//TODO: make the default range for all non-bounded `next_i/u*` the same range as drand48's. If that's too big for the integer type, scale it down.
}
void rng_test()
{
rng::crand r(123);
printf("%lu %lu %lu\n", r.next_u64(), r.next_u64(), r.next_u64());
}