From 65987328924fee55d00415e5bb5377a8b29e9e45 Mon Sep 17 00:00:00 2001 From: "Yukihiro \"Matz\" Matsumoto" Date: Fri, 26 Aug 2022 12:37:54 +0900 Subject: [PATCH] numeric_ext.c (int_powm): try bigint pow when overflow. --- mrbgems/mruby-numeric-ext/src/numeric_ext.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/mrbgems/mruby-numeric-ext/src/numeric_ext.c b/mrbgems/mruby-numeric-ext/src/numeric_ext.c index fb4066bf1..ce95bc204 100644 --- a/mrbgems/mruby-numeric-ext/src/numeric_ext.c +++ b/mrbgems/mruby-numeric-ext/src/numeric_ext.c @@ -59,19 +59,19 @@ static mrb_value int_powm(mrb_state *mrb, mrb_value x) { mrb_value m; - mrb_int base, exp, mod, result = 1; + mrb_int base, e, exp, mod, result = 1; if (mrb_get_argc(mrb) == 1) { return mrb_int_pow(mrb, x, mrb_get_arg1(mrb)); } - mrb_get_args(mrb, "io", &exp, &m); - if (exp < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "int.pow(n,m): n must be positive"); + mrb_get_args(mrb, "io", &e, &m); + if (e < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "int.pow(n,m): n must be positive"); #ifdef MRB_USE_BIGINT if (mrb_bigint_p(x)) { - return mrb_bint_powm(mrb, x, exp, m); + return mrb_bint_powm(mrb, x, e, m); } if (mrb_bigint_p(m)) { - return mrb_bint_powm(mrb, mrb_bint_new_int(mrb, mrb_integer(x)), exp, m); + return mrb_bint_powm(mrb, mrb_bint_new_int(mrb, mrb_integer(x)), e, m); } #endif if (!mrb_integer_p(m)) mrb_raise(mrb, E_TYPE_ERROR, "int.pow(n,m): m must be integer"); @@ -80,17 +80,26 @@ int_powm(mrb_state *mrb, mrb_value x) if (mod == 0) mrb_int_zerodiv(mrb); if (mod == 1) return mrb_fixnum_value(0); base = mrb_integer(x); + exp = e; for (;;) { if (exp & 1) { if (mrb_int_mul_overflow(result, base, &result)) { +#ifdef MRB_USE_BIGINT + return mrb_bint_powm(mrb, mrb_bint_new_int(mrb, mrb_integer(x)), e, m); +#else mrb_int_overflow(mrb, "pow"); +#endif } result %= mod; } exp >>= 1; if (exp == 0) break; if (mrb_int_mul_overflow(base, base, &base)) { +#ifdef MRB_USE_BIGINT + return mrb_bint_powm(mrb, mrb_bint_new_int(mrb, mrb_integer(x)), e, m); +#else mrb_int_overflow(mrb, "pow"); +#endif } base %= mod; }