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mruby-bigint (int_fit_limb_p): fix the logic to check mrb_int size

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`int_fit_limb_p()` checks if `mrb_int` fits in `mp_limb`. Previous logic
did not work well with negative integers.
This commit is contained in:
Yukihiro "Matz" Matsumoto
2024-11-20 11:27:54 +09:00
parent 33357d4f35
commit dc5566e560
1 changed files with 24 additions and 2 deletions
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mrbgems/mruby-bigint/core/bigint.c
+24 -2
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@@ -1477,6 +1477,28 @@ mrb_bint_as_uint64(mrb_state *mrb, mrb_value x)
return u;
}
static mrb_bool
int_fit_limb_p(mrb_int i)
{
#ifdef MRB_INT64
#if DIG_SIZE == 32
// if mp_limb is int32_t
return (i >= INT32_MIN && i <= INT32_MAX);
#else /* if DIG_SIZE == 16 */
// if mp_limb is int16_t
return (i >= INT16_MIN && i <= INT16_MAX);
#endif
#else /* MRB_INT32 */
#if DIG_SIZE == 32
// if mp_limb is also int32_t, it always fits
return true;
#else /* if DIG_SIZE == 16 */
// if mp_limb is int16_t
return (i >= INT16_MIN && i <= INT16_MAX);
#endif
#endif
}
/* unnormalize version of mrb_bint_add */
mrb_value
mrb_bint_add_n(mrb_state *mrb, mrb_value x, mrb_value y)
@@ -1486,7 +1508,7 @@ mrb_bint_add_n(mrb_state *mrb, mrb_value x, mrb_value y)
bint_as_mpz(RBIGINT(x), &a);
if (mrb_integer_p(y)) {
mrb_int i = mrb_integer(y);
if (LOW(i) == i) {
if (int_fit_limb_p(i)) {
mpz_init_set(mrb, &z, &a);
if ((i > 0) ^ (z.sn > 0)) {
mpz_sub_int(mrb, &z, i);
@@ -1529,7 +1551,7 @@ mrb_bint_sub_n(mrb_state *mrb, mrb_value x, mrb_value y)
bint_as_mpz(RBIGINT(x), &a);
if (mrb_integer_p(y)) {
mrb_int i = mrb_integer(y);
if (LOW(i) == i) {
if (int_fit_limb_p(i)) {
mpz_init_set(mrb, &z, &a);
if ((i > 0) ^ (z.sn > 0)) {
mpz_add_int(mrb, &z, i);