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-rw-r--r--src/mp.c68
1 files changed, 57 insertions, 11 deletions
diff --git a/src/mp.c b/src/mp.c
index c66285e..d7fcc75 100644
--- a/src/mp.c
+++ b/src/mp.c
@@ -383,7 +383,7 @@ void
mp_logarithm(int64_t n, const MPNumber *x, MPNumber *z)
{
/* log(0) undefined */
- if (mp_is_zero(x))
+ if (mp_is_zero(x))
{
/* Translators: Error displayed when attempting to take logarithm of zero */
mperr(_("Logarithm of zero is undefined"));
@@ -525,19 +525,65 @@ mp_modulus_divide(const MPNumber *x, const MPNumber *y, MPNumber *z)
return;
}
- mp_set_from_mp(x, z);
- mp_divide(x, y, z);
- mp_floor(z, z);
- mp_multiply(z, y, z);
- mp_subtract(x, z, z);
-
MPNumber t1 = mp_new();
+ MPNumber t2 = mp_new();
+
+ mp_divide(x, y, &t1);
+ mp_floor(&t1, &t1);
+ mp_multiply(&t1, y, &t2);
+ mp_subtract(x, &t2, z);
+
mp_set_from_integer(0, &t1);
if ((mp_compare(y, &t1) < 0 && mp_compare(z, &t1) > 0) ||
(mp_compare(y, &t1) > 0 && mp_compare(z, &t1) < 0))
mp_add(z, y, z);
mp_clear(&t1);
+ mp_clear(&t2);
+}
+
+
+void
+mp_modular_exponentiation(const MPNumber *x, const MPNumber *y, const MPNumber *p, MPNumber *z)
+{
+ MPNumber base_value = mp_new();
+ MPNumber exp_value = mp_new();
+ MPNumber ans = mp_new();
+ MPNumber two = mp_new();
+ MPNumber tmp = mp_new();
+
+ mp_set_from_integer(1, &ans);
+ mp_set_from_integer(2, &two);
+ mp_abs(y, &exp_value);
+
+ if (mp_is_negative(y))
+ mp_reciprocal(x, &base_value);
+ else
+ mp_set_from_mp(x, &base_value);
+
+ while (!mp_is_zero(&exp_value))
+ {
+ mp_modulus_divide(&exp_value, &two, &tmp);
+
+ bool is_even = mp_is_zero(&tmp);
+ if (!is_even)
+ {
+ mp_multiply(&ans, &base_value, &ans);
+ mp_modulus_divide(&ans, p, &ans);
+ }
+ mp_multiply(&base_value, &base_value, &base_value);
+ mp_modulus_divide(&base_value, p, &base_value);
+ mp_divide_integer(&exp_value, 2, &exp_value);
+ mp_floor(&exp_value, &exp_value);
+ }
+
+ mp_modulus_divide(&ans, p, z);
+
+ mp_clear(&base_value);
+ mp_clear(&exp_value);
+ mp_clear(&ans);
+ mp_clear(&two);
+ mp_clear(&tmp);
}
@@ -694,7 +740,7 @@ mp_factorize(const MPNumber *x)
list = g_list_append(list, factor);
factor = g_slice_alloc0(sizeof(MPNumber));
mpc_init2(factor->num, PRECISION);
- }
+ }
else
{
mp_add_integer(&divisor, 2, &tmp);
@@ -707,8 +753,8 @@ mp_factorize(const MPNumber *x)
{
mp_set_from_mp(&value, factor);
list = g_list_append(list, factor);
- }
- else
+ }
+ else
{
mpc_clear(factor->num);
g_slice_free(MPNumber, factor);
@@ -758,7 +804,7 @@ mp_factorize_unit64(uint64_t n)
mp_set_from_unsigned_integer(n, factor);
list = g_list_append(list, factor);
}
- else
+ else
{
mpc_clear(factor->num);
g_slice_free(MPNumber, factor);