ProjectEuler/c/src/primes.h

#ifdef _PRIMES_H
#define _PRIMES_H


#include <stdint.h>
#include <stdbool.h>

#include "da.h"

DA_STRUCT_DEF(uint64_t, primes);

bool isprime(uint64_t n);
void primes_fill(struct primes_da *primes);
void primes_fill_with(struct primes *primes, uint64_t n);

#if defined(IMP) || defined(PRIMES_IMP)

void
primes_fill_with(struct primes *primes, uint64_t n)
{
	uint64_t i = 0;
	for ( ; primes->size < n; ++i ) {
		if ( isprime(i) ) {
			DA_APPEND(*primes, i);
		}
	}
}

bool
isprime(uint64_t n)
{
	uint64_t i = 0;
	if ( (n & 1) == 0 ) {
		return ( n == 2 );
	}

	for ( i = 2; i < n; ++i ) {
		if ( (n % i) == 0 ) {
			return false;
		}
	}
	return true;
}

void
primes_fill(struct primes_da *primes)
{
	uint64_t i = primes->size;
	if ( i == 0 ) {
		i = 2;
	}
	for ( ; primes->size < primes->cap; ++i ) {
		if ( isprime(i) ) {
			primes->data[primes->size++] = i;
		}
	}
}

#endif /* defined(IMP) || defined(PRIMES_IMP) */



#endif /* _PRIMES_H */