diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | time.c | 136 |
2 files changed, 111 insertions, 30 deletions
@@ -1,3 +1,8 @@ +Wed Mar 31 23:33:29 2010 Tanaka Akira <akr@fsij.org> + + * time.c (long_mul): extracted from mul and avoid integer overflow. + (wi_mul): extracted from wmul and avoid integer overflow. + Wed Mar 31 21:30:38 2010 Tanaka Akira <akr@fsij.org> * time.c: less bignum allocations. @@ -78,6 +78,50 @@ sub(VALUE x, VALUE y) return rb_funcall(x, '-', 1, y); } +#if !(HAVE_LONG_LONG && SIZEOF_LONG * 2 <= SIZEOF_LONG_LONG) +static int +long_mul(long x, long y, long *z) +{ + unsigned long a, b, c; + int s; + if (x == 0 || y == 0) { + *z = 0; + return 1; + } + if (x < 0) { + s = -1; + a = (unsigned long)-x; + } + else { + s = 1; + a = (unsigned long)x; + } + if (y < 0) { + s = -s; + b = (unsigned long)-y; + } + else { + b = (unsigned long)y; + } + c = a * b; + if (c / b == a) { + if (s < 0) { + if (c <= (unsigned long)LONG_MAX + 1) { + *z = -(long)c; + return 1; + } + } + else { + if (c <= (unsigned long)LONG_MAX) { + *z = (long)c; + return 1; + } + } + } + return 0; +} +#endif + static VALUE mul(VALUE x, VALUE y) { @@ -88,14 +132,9 @@ mul(VALUE x, VALUE y) return LONG2FIX(ll); return LL2NUM(ll); #else - long a, b, c; - a = FIX2LONG(x); - if (a == 0) - return x; - b = FIX2LONG(y); - c = a * b; - if (c / a == b) - return LONG2NUM(c); + long z; + if (long_mul(FIX2LONG(x), FIX2LONG(y), &z)) + return LONG2NUM(z); #endif } if (TYPE(x) == T_BIGNUM) @@ -171,13 +210,14 @@ divmodv(VALUE n, VALUE d, VALUE *q, VALUE *r) typedef uint64_t WIDEVALUE; typedef int64_t SIGNED_WIDEVALUE; # define WIDEVALUE_IS_WIDER 1 +# define UWIDEINT_MAX UINT64_MAX +# define WIDEINT_MAX INT64_MAX +# define WIDEINT_MIN INT64_MIN # define FIXWINT_P(tv) ((tv) & 1) # define FIXWVtoINT64(tv) RSHIFT((SIGNED_WIDEVALUE)(tv), 1) # define INT64toFIXWV(wi) ((WIDEVALUE)((SIGNED_WIDEVALUE)(wi) << 1 | FIXNUM_FLAG)) # define FIXWV_MAX (((int64_t)1 << 62) - 1) # define FIXWV_MIN (-((int64_t)1 << 62)) -# define POSFIXWVABLE(wi) ((wi) < FIXWV_MAX+1) -# define NEGFIXWVABLE(wi) ((wi) >= FIXWV_MIN) # define FIXWVABLE(wi) (POSFIXWVABLE(wi) && NEGFIXWVABLE(wi)) # define WINT2FIXWV(i) WIDEVAL_WRAP(INT64toFIXWV(i)) # define FIXWV2WINT(w) FIXWVtoINT64(WIDEVAL_GET(w)) @@ -187,15 +227,23 @@ divmodv(VALUE n, VALUE d, VALUE *q, VALUE *r) typedef VALUE WIDEVALUE; typedef SIGNED_VALUE SIGNED_WIDEVALUE; # define WIDEVALUE_IS_WIDER 0 +# define UWIDEINT_MAX ULONG_MAX +# define WIDEINT_MAX LONG_MAX +# define WIDEINT_MIN LONG_MIN # define FIXWINT_P(v) FIXNUM_P(v) +# define FIXWV_MAX FIXNUM_MAX +# define FIXWV_MIN FIXNUM_MIN # define FIXWVABLE(i) FIXABLE(i) # define WINT2FIXWV(i) WIDEVAL_WRAP(LONG2FIX(i)) # define FIXWV2WINT(w) FIX2LONG(WIDEVAL_GET(w)) #endif +#define POSFIXWVABLE(wi) ((wi) < FIXWV_MAX+1) +#define NEGFIXWVABLE(wi) ((wi) >= FIXWV_MIN) #define FIXWV_P(w) FIXWINT_P(WIDEVAL_GET(w)) /* #define STRUCT_WIDEVAL */ +#define STRUCT_WIDEVAL #ifdef STRUCT_WIDEVAL /* for type checking */ typedef struct { @@ -406,20 +454,57 @@ wsub(wideval_t wx, wideval_t wy) return v2w(rb_funcall(x, '-', 1, w2v(wy))); } +static int +wi_mul(wideint_t x, wideint_t y, wideint_t *z) +{ + uwideint_t a, b, c; + int s; + if (x == 0 || y == 0) { + *z = 0; + return 1; + } + if (x < 0) { + s = -1; + a = (uwideint_t)-x; + } + else { + s = 1; + a = (uwideint_t)x; + } + if (y < 0) { + s = -s; + b = (uwideint_t)-y; + } + else { + b = (uwideint_t)y; + } + c = a * b; + if (c / b == a) { + if (s < 0) { + if (c <= (uwideint_t)WIDEINT_MAX + 1) { + *z = -(wideint_t)c; + return 1; + } + } + else { + if (c <= (uwideint_t)WIDEINT_MAX) { + *z = (wideint_t)c; + return 1; + } + } + } + return 0; +} + static wideval_t wmul(wideval_t wx, wideval_t wy) { VALUE x, z; #if WIDEVALUE_IS_WIDER if (FIXWV_P(wx) && FIXWV_P(wy)) { - wideint_t a, b, c; - a = FIXWV2WINT(wx); - if (a == 0) return wx; - b = FIXWV2WINT(wy); - c = a * b; - if (c / a == b) { - return WINT2WV(c); - } + wideint_t z; + if (wi_mul(FIXWV2WINT(wx), FIXWV2WINT(wy), &z)) + return WINT2WV(z); } #endif x = w2v(wx); @@ -643,18 +728,9 @@ static wideval_t rb_time_magnify(wideval_t w) { if (FIXWV_P(w)) { - wideint_t a, b, c; - a = FIXWV2WINT(w); - if (a == 0) { - return WINT2FIXWV(0); - } - b = TIME_SCALE; - c = a * b; - if (c / b == a) { - if (FIXWVABLE(c)) { - return WINT2FIXWV(c); - } - } + wideint_t z; + if (wi_mul(FIXWV2WINT(w), TIME_SCALE, &z)) + return WINT2WV(z); } return wmul(w, WINT2FIXWV(TIME_SCALE)); } |