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analog: Add equality check for sr_rational

This commit is contained in:
Stefan Brüns 2016-04-22 23:15:54 +02:00 committed by Uwe Hermann
parent e9869966be
commit bdba362695
3 changed files with 110 additions and 0 deletions
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1
include/libsigrok/proto.h
View File

@ -33,6 +33,7 @@ SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog *analog,
char **result);
SR_API void sr_rational_set(struct sr_rational *r, int64_t p, uint64_t q);
SR_API int sr_rational_eq(const struct sr_rational *a, const struct sr_rational *b);
/*--- backend.c -------------------------------------------------------------*/

79
src/analog.c
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@ -354,4 +354,83 @@ SR_API void sr_rational_set(struct sr_rational *r, int64_t p, uint64_t q)
r->q = q;
}
#ifndef HAVE___INT128_T
struct sr_int128_t {
int64_t high;
uint64_t low;
};
struct sr_uint128_t {
uint64_t high;
uint64_t low;
};
static void mult_int64(struct sr_int128_t *res, const int64_t a,
const int64_t b)
{
uint64_t t1, t2, t3, t4;
t1 = (UINT32_MAX & a) * (UINT32_MAX & b);
t2 = (UINT32_MAX & a) * (b >> 32);
t3 = (a >> 32) * (UINT32_MAX & b);
t4 = (a >> 32) * (b >> 32);
res->low = t1 + (t2 << 32) + (t3 << 32);
res->high = (t1 >> 32) + (uint64_t)((uint32_t)(t2)) + (uint64_t)((uint32_t)(t3));
res->high >>= 32;
res->high += ((int64_t)t2 >> 32) + ((int64_t)t3 >> 32) + t4;
}
static void mult_uint64(struct sr_uint128_t *res, const uint64_t a,
const uint64_t b)
{
uint64_t t1, t2, t3, t4;
// (x1 + x2) * (y1 + y2) = x1*y1 + x1*y2 + x2*y1 + x2*y2
t1 = (UINT32_MAX & a) * (UINT32_MAX & b);
t2 = (UINT32_MAX & a) * (b >> 32);
t3 = (a >> 32) * (UINT32_MAX & b);
t4 = (a >> 32) * (b >> 32);
res->low = t1 + (t2 << 32) + (t3 << 32);
res->high = (t1 >> 32) + (uint64_t)((uint32_t)(t2)) + (uint64_t)((uint32_t)(t3));
res->high >>= 32;
res->high += ((int64_t)t2 >> 32) + ((int64_t)t3 >> 32) + t4;
}
#endif
/**
* Compare two sr_rational for equality
*
* @param[in] a First value
* @param[in] b Second value
*
* The values are compared for numerical equality, i.e. 2/10 == 1/5
*
* @retval 1 if both values are equal
* @retval 0 otherwise
*
* @since 0.5.0
*/
SR_API int sr_rational_eq(const struct sr_rational *a, const struct sr_rational *b)
{
#ifdef HAVE___INT128_T
__int128_t m1, m2;
/* p1/q1 = p2/q2 <=> p1*q2 = p2*q1 */
m1 = ((__int128_t)(b->p)) * ((__uint128_t)a->q);
m2 = ((__int128_t)(a->p)) * ((__uint128_t)b->q);
return (m1 == m2);
#else
struct sr_int128_t m1, m2;
mult_int64(&m1, a->q, b->p);
mult_int64(&m2, a->p, b->q);
return (m1.high == m2.high) && (m1.low == m2.low);
#endif
}
/** @} */

30
tests/analog.c
View File

@ -196,6 +196,35 @@ START_TEST(test_set_rational_null)
}
END_TEST
START_TEST(test_cmp_rational)
{
const struct sr_rational r[] = { { 1, 1 },
{ 2, 2 },
{ 1000, 1000 },
{ INT64_MAX, INT64_MAX },
{ 1, 4 },
{ 2, 8 },
{ INT64_MAX, UINT64_MAX },
{ INT64_MIN, UINT64_MAX },
};
fail_unless(sr_rational_eq(&r[0], &r[0]) == 1);
fail_unless(sr_rational_eq(&r[0], &r[1]) == 1);
fail_unless(sr_rational_eq(&r[1], &r[2]) == 1);
fail_unless(sr_rational_eq(&r[2], &r[3]) == 1);
fail_unless(sr_rational_eq(&r[3], &r[3]) == 1);
fail_unless(sr_rational_eq(&r[4], &r[4]) == 1);
fail_unless(sr_rational_eq(&r[4], &r[5]) == 1);
fail_unless(sr_rational_eq(&r[5], &r[5]) == 1);
fail_unless(sr_rational_eq(&r[6], &r[6]) == 1);
fail_unless(sr_rational_eq(&r[7], &r[7]) == 1);
fail_unless(sr_rational_eq(&r[1], &r[4]) == 0);
}
END_TEST
Suite *suite_analog(void)
{
Suite *s;
@ -210,6 +239,7 @@ Suite *suite_analog(void)
tcase_add_test(tc, test_analog_unit_to_string_null);
tcase_add_test(tc, test_set_rational);
tcase_add_test(tc, test_set_rational_null);
tcase_add_test(tc, test_cmp_rational);
suite_add_tcase(s, tc);
return s;