#endif
}
+/**
+ * Multiply two sr_rational
+ *
+ * @param[in] a First value
+ * @param[in] b Second value
+ * @param[out] res Result
+ *
+ * The resulting nominator/denominator are reduced if the result would not fit
+ * otherwise. If the resulting nominator/denominator are relatively prime,
+ * this may not be possible.
+ *
+ * It is save to use the same variable for result and input values
+ *
+ * @retval SR_OK Success.
+ * @retval SR_ERR_ARG Resulting value to large
+ *
+ * @since 0.5.0
+ */
+SR_API int sr_rational_mult(struct sr_rational *res, const struct sr_rational *a,
+ const struct sr_rational *b)
+{
+#ifdef HAVE___INT128_T
+ __int128_t p;
+ __uint128_t q;
+
+ p = (__int128_t)(a->p) * (__int128_t)(b->p);
+ q = (__uint128_t)(a->q) * (__uint128_t)(b->q);
+
+ if ((p > INT64_MAX) || (p < INT64_MIN) || (q > UINT64_MAX)) {
+ while (!((p & 1) || (q & 1))) {
+ p /= 2;
+ q /= 2;
+ }
+ }
+
+ if ((p > INT64_MAX) || (p < INT64_MIN) || (q > UINT64_MAX)) {
+ // TODO: determine gcd to do further reduction
+ return SR_ERR_ARG;
+ }
+
+ res->p = (int64_t)(p);
+ res->q = (uint64_t)(q);
+
+ return SR_OK;
+
+#else
+ struct sr_int128_t p;
+ struct sr_uint128_t q;
+
+ mult_int64(&p, a->p, b->p);
+ mult_uint64(&q, a->q, b->q);
+
+ while (!(p.low & 1) && !(q.low & 1)) {
+ p.low /= 2;
+ if (p.high & 1) p.low |= (1ll << 63);
+ p.high >>= 1;
+ q.low /= 2;
+ if (q.high & 1) q.low |= (1ll << 63);
+ q.high >>= 1;
+ }
+
+ if (q.high)
+ return SR_ERR_ARG;
+ if ((p.high >= 0) && (p.low > INT64_MAX))
+ return SR_ERR_ARG;
+ if (p.high < -1)
+ return SR_ERR_ARG;
+
+ res->p = (int64_t)p.low;
+ res->q = q.low;
+
+ return SR_OK;
+#endif
+}
+
+/**
+ * Divide rational a by rational b
+ *
+ * @param[in] num numerator
+ * @param[in] div divisor
+ * @param[out] res Result
+ *
+ * The resulting nominator/denominator are reduced if the result would not fit
+ * otherwise. If the resulting nominator/denominator are relatively prime,
+ * this may not be possible.
+ *
+ * It is save to use the same variable for result and input values
+ *
+ * @retval SR_OK Success.
+ * @retval SR_ERR_ARG Division by zero
+ * @retval SR_ERR_ARG Denominator of divisor to large
+ * @retval SR_ERR_ARG Resulting value to large
+ *
+ * @since 0.5.0
+ */
+SR_API int sr_rational_div(struct sr_rational *res, const struct sr_rational *num,
+ const struct sr_rational *div)
+{
+ struct sr_rational t;
+
+ if (div->q > INT64_MAX)
+ return SR_ERR_ARG;
+ if (div->p == 0)
+ return SR_ERR_ARG;
+
+ if (div->p > 0) {
+ t.p = div->q;
+ t.q = div->p;
+ } else {
+ t.p = -div->q;
+ t.q = -div->p;
+ }
+
+ return sr_rational_mult(res, num, &t);
+}
+
/** @} */