utils.c


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#include <stdlib.h>
#include <errno.h>
#include <stdint.h>
#include <limits.h>

int
strtou16_strict(const char *str, uint16_t *result)
{
	char *end;
	long val;

	if (!str)
		return -EINVAL;

	errno = 0;
	val = strtol(str, &end, 10);

	if (errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
		return -EINVAL;
	
	if (errno != 0 && val == 0)
		return -EINVAL;

	if (end == str)
		return -EINVAL;

	if (*end != '\0')
		return -EINVAL;

	if (val < 1 || val > UINT16_MAX)
		return -EINVAL;

	if (result)
		*result = val;
	return 0;
}