diff options
| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | bignum.c | 54 |
2 files changed, 38 insertions, 20 deletions
@@ -1,3 +1,7 @@ +Fri Apr 27 00:03:48 2007 Nobuyoshi Nakada <nobu@ruby-lang.org> + + * bignum.c (rb_big_pow): truncate all zero BDIGITs. [ruby-dev:30733] + Thu Apr 26 17:31:00 2007 Nobuyoshi Nakada <nobu@ruby-lang.org> * bignum.c (rb_big_pow): reduce multiplying for even number. @@ -90,34 +90,48 @@ rb_big_2comp(VALUE x) /* get 2's complement */ } static VALUE -bignorm(VALUE x) +bigtrunc(VALUE x) { - if (FIXNUM_P(x)) { - return x; - } - else if (TYPE(x) == T_BIGNUM) { - long len = RBIGNUM(x)->len; - BDIGIT *ds = BDIGITS(x); + long len = RBIGNUM(x)->len; + BDIGIT *ds = BDIGITS(x); - while (len-- && !ds[len]) ; - RBIGNUM(x)->len = ++len; + while (len-- && !ds[len]); + RBIGNUM(x)->len = ++len; + return x; +} + +static VALUE +bigfixize(VALUE x) +{ + long len = RBIGNUM(x)->len; + BDIGIT *ds = BDIGITS(x); - if (len*SIZEOF_BDIGITS <= sizeof(VALUE)) { - SIGNED_VALUE num = 0; - while (len--) { - num = BIGUP(num) + ds[len]; + if (len*SIZEOF_BDIGITS <= sizeof(VALUE)) { + SIGNED_VALUE num = 0; + while (len--) { + num = BIGUP(num) + ds[len]; + } + if (num >= 0) { + if (RBIGNUM(x)->sign) { + if (POSFIXABLE(num)) return LONG2FIX(num); } - if (num >= 0) { - if (RBIGNUM(x)->sign) { - if (POSFIXABLE(num)) return LONG2FIX(num); - } - else if (NEGFIXABLE(-(long)num)) return LONG2FIX(-(long)num); + else { + if (NEGFIXABLE(-(long)num)) return LONG2FIX(-(long)num); } } } return x; } +static VALUE +bignorm(VALUE x) +{ + if (!FIXNUM_P(x) && TYPE(x) == T_BIGNUM) { + x = bigfixize(bigtrunc(x)); + } + return x; +} + VALUE rb_big_norm(VALUE x) { @@ -1563,10 +1577,10 @@ rb_big_pow(VALUE x, VALUE y) do { yy /= 2; x = rb_big_mul0(x, x); - if (!BDIGITS(x)[RBIGNUM(x)->len-1]) RBIGNUM(x)->len--; + bigtrunc(x); } while (yy % 2 == 0); z = z ? rb_big_mul0(z, x) : x; - if (!BDIGITS(z)[RBIGNUM(z)->len-1]) RBIGNUM(z)->len--; + bigtrunc(z); } return bignorm(z); } |