class Bignum
Bignum objects hold integers outside the range of Fixnum. Bignum objects are created automatically when integer calculations would otherwise overflow a Fixnum. When a calculation involving Bignum objects returns a result that will fit in a Fixnum, the result is automatically converted.
For the purposes of the bitwise operations and []
, a Bignum is treated as if it were an infinite-length
bitstring with 2's complement representation.
While Fixnum values are immediate, Bignum objects are not—assignment and parameter passing work with references to objects, not the objects themselves.
When mathn is required Bignum's division and exponentiation are enhanced to return more precise values from mathematical expressions.
Constants
- GMP_VERSION
Public Instance Methods
Returns big modulo other. See Numeric#divmod for more information.
VALUE rb_big_modulo(VALUE x, VALUE y) { VALUE z; if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (!RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bin(x, y, '%'); } bigdivmod(x, y, 0, &z); return bignorm(z); }
Performs bitwise and
between big and
numeric.
VALUE rb_big_and(VALUE x, VALUE y) { VALUE z; BDIGIT *ds1, *ds2, *zds; long i, xn, yn, n1, n2; BDIGIT hibitsx, hibitsy; BDIGIT hibits1, hibits2; VALUE tmpv; BDIGIT tmph; long tmpn; if (!FIXNUM_P(y) && !RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bit(x, y, '&'); } hibitsx = abs2twocomp(&x, &xn); if (FIXNUM_P(y)) { return bigand_int(x, xn, hibitsx, FIX2LONG(y)); } hibitsy = abs2twocomp(&y, &yn); if (xn > yn) { tmpv = x; x = y; y = tmpv; tmpn = xn; xn = yn; yn = tmpn; tmph = hibitsx; hibitsx = hibitsy; hibitsy = tmph; } n1 = xn; n2 = yn; ds1 = BDIGITS(x); ds2 = BDIGITS(y); hibits1 = hibitsx; hibits2 = hibitsy; if (!hibits1) n2 = n1; z = bignew(n2, 0); zds = BDIGITS(z); for (i=0; i<n1; i++) { zds[i] = ds1[i] & ds2[i]; } for (; i<n2; i++) { zds[i] = hibits1 & ds2[i]; } twocomp2abs_bang(z, hibits1 && hibits2); RB_GC_GUARD(x); RB_GC_GUARD(y); return bignorm(z); }
Multiplies big and other, returning the result.
VALUE rb_big_mul(VALUE x, VALUE y) { if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (RB_BIGNUM_TYPE_P(y)) { } else if (RB_FLOAT_TYPE_P(y)) { return DBL2NUM(rb_big2dbl(x) * RFLOAT_VALUE(y)); } else { return rb_num_coerce_bin(x, y, '*'); } return bignorm(bigmul0(x, y)); }
Raises big to the exponent power (which may be an integer, float, or anything that will coerce to a number). The result may be a Fixnum, Bignum, or Float
123456789 ** 2 #=> 15241578750190521 123456789 ** 1.2 #=> 5126464716.09932 123456789 ** -2 #=> 6.5610001194102e-17
VALUE rb_big_pow(VALUE x, VALUE y) { double d; SIGNED_VALUE yy; again: if (y == INT2FIX(0)) return INT2FIX(1); if (RB_FLOAT_TYPE_P(y)) { d = RFLOAT_VALUE(y); if ((!RBIGNUM_SIGN(x) && !BIGZEROP(x)) && d != round(d)) return rb_funcall(rb_complex_raw1(x), rb_intern("**"), 1, y); } else if (RB_BIGNUM_TYPE_P(y)) { y = bignorm(y); if (FIXNUM_P(y)) goto again; rb_warn("in a**b, b may be too big"); d = rb_big2dbl(y); } else if (FIXNUM_P(y)) { yy = FIX2LONG(y); if (yy < 0) return rb_funcall(rb_rational_raw1(x), rb_intern("**"), 1, y); else { VALUE z = 0; SIGNED_VALUE mask; const size_t xbits = rb_absint_numwords(x, 1, NULL); const size_t BIGLEN_LIMIT = 32*1024*1024; if (xbits == (size_t)-1 || (xbits > BIGLEN_LIMIT) || (xbits * yy > BIGLEN_LIMIT)) { rb_warn("in a**b, b may be too big"); d = (double)yy; } else { for (mask = FIXNUM_MAX + 1; mask; mask >>= 1) { if (z) z = bigsq(z); if (yy & mask) { z = z ? bigtrunc(bigmul0(z, x)) : x; } } return bignorm(z); } } } else { return rb_num_coerce_bin(x, y, rb_intern("**")); } return DBL2NUM(pow(rb_big2dbl(x), d)); }
Adds big and other, returning the result.
VALUE rb_big_plus(VALUE x, VALUE y) { long n; if (FIXNUM_P(y)) { n = FIX2LONG(y); if ((n > 0) != RBIGNUM_SIGN(x)) { if (n < 0) { n = -n; } return bigsub_int(x, n); } if (n < 0) { n = -n; } return bigadd_int(x, n); } else if (RB_BIGNUM_TYPE_P(y)) { return bignorm(bigadd(x, y, 1)); } else if (RB_FLOAT_TYPE_P(y)) { return DBL2NUM(rb_big2dbl(x) + RFLOAT_VALUE(y)); } else { return rb_num_coerce_bin(x, y, '+'); } }
Subtracts other from big, returning the result.
VALUE rb_big_minus(VALUE x, VALUE y) { long n; if (FIXNUM_P(y)) { n = FIX2LONG(y); if ((n > 0) != RBIGNUM_SIGN(x)) { if (n < 0) { n = -n; } return bigadd_int(x, n); } if (n < 0) { n = -n; } return bigsub_int(x, n); } else if (RB_BIGNUM_TYPE_P(y)) { return bignorm(bigadd(x, y, 0)); } else if (RB_FLOAT_TYPE_P(y)) { return DBL2NUM(rb_big2dbl(x) - RFLOAT_VALUE(y)); } else { return rb_num_coerce_bin(x, y, '-'); } }
Unary minus (returns an integer whose value is 0-big)
VALUE rb_big_uminus(VALUE x) { VALUE z = rb_big_clone(x); RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(x)); return bignorm(z); }
Performs division: the class of the resulting object depends on the class
of numeric
and on the magnitude of the result.
VALUE rb_big_div(VALUE x, VALUE y) { return rb_big_divide(x, y, '/'); }
Returns true
if the value of big
is less than
that of real
.
static VALUE big_lt(VALUE x, VALUE y) { return big_op(x, y, big_op_lt); }
Shifts big left numeric positions (right if numeric is negative).
VALUE rb_big_lshift(VALUE x, VALUE y) { int lshift_p; size_t shift_numdigits; int shift_numbits; for (;;) { if (FIXNUM_P(y)) { long l = FIX2LONG(y); unsigned long shift; if (0 <= l) { lshift_p = 1; shift = l; } else { lshift_p = 0; shift = 1+(unsigned long)(-(l+1)); } shift_numbits = (int)(shift & (BITSPERDIG-1)); shift_numdigits = shift >> bit_length(BITSPERDIG-1); return bignorm(big_shift3(x, lshift_p, shift_numdigits, shift_numbits)); } else if (RB_BIGNUM_TYPE_P(y)) { return bignorm(big_shift2(x, 1, y)); } y = rb_to_int(y); } }
Returns true
if the value of big
is less than or
equal to that of real
.
static VALUE big_le(VALUE x, VALUE y) { return big_op(x, y, big_op_le); }
Comparison—Returns -1, 0, or +1 depending on whether big
is
less than, equal to, or greater than numeric
. This is the
basis for the tests in Comparable.
nil
is returned if the two values are incomparable.
VALUE rb_big_cmp(VALUE x, VALUE y) { int cmp; if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (RB_BIGNUM_TYPE_P(y)) { } else if (RB_FLOAT_TYPE_P(y)) { return rb_integer_float_cmp(x, y); } else { return rb_num_coerce_cmp(x, y, rb_intern("<=>")); } if (RBIGNUM_SIGN(x) > RBIGNUM_SIGN(y)) return INT2FIX(1); if (RBIGNUM_SIGN(x) < RBIGNUM_SIGN(y)) return INT2FIX(-1); cmp = bary_cmp(BDIGITS(x), RBIGNUM_LEN(x), BDIGITS(y), RBIGNUM_LEN(y)); if (RBIGNUM_SIGN(x)) return INT2FIX(cmp); else return INT2FIX(-cmp); }
Returns true
only if obj has the same value as
big. Contrast this with Bignum#eql?
, which requires
obj to be a Bignum
.
68719476736 == 68719476736.0 #=> true
VALUE rb_big_eq(VALUE x, VALUE y) { if (FIXNUM_P(y)) { if (bignorm(x) == y) return Qtrue; y = rb_int2big(FIX2LONG(y)); } else if (RB_BIGNUM_TYPE_P(y)) { } else if (RB_FLOAT_TYPE_P(y)) { return rb_integer_float_eq(x, y); } else { return rb_equal(y, x); } if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y)) return Qfalse; if (RBIGNUM_LEN(x) != RBIGNUM_LEN(y)) return Qfalse; if (MEMCMP(BDIGITS(x),BDIGITS(y),BDIGIT,RBIGNUM_LEN(y)) != 0) return Qfalse; return Qtrue; }
Returns true
only if obj has the same value as
big. Contrast this with Bignum#eql?
, which requires
obj to be a Bignum
.
68719476736 == 68719476736.0 #=> true
VALUE rb_big_eq(VALUE x, VALUE y) { if (FIXNUM_P(y)) { if (bignorm(x) == y) return Qtrue; y = rb_int2big(FIX2LONG(y)); } else if (RB_BIGNUM_TYPE_P(y)) { } else if (RB_FLOAT_TYPE_P(y)) { return rb_integer_float_eq(x, y); } else { return rb_equal(y, x); } if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y)) return Qfalse; if (RBIGNUM_LEN(x) != RBIGNUM_LEN(y)) return Qfalse; if (MEMCMP(BDIGITS(x),BDIGITS(y),BDIGIT,RBIGNUM_LEN(y)) != 0) return Qfalse; return Qtrue; }
Returns true
if the value of big
is greater than
that of real
.
static VALUE big_gt(VALUE x, VALUE y) { return big_op(x, y, big_op_gt); }
Returns true
if the value of big
is greater than
or equal to that of real
.
static VALUE big_ge(VALUE x, VALUE y) { return big_op(x, y, big_op_ge); }
Shifts big right numeric positions (left if numeric is negative).
VALUE rb_big_rshift(VALUE x, VALUE y) { int lshift_p; size_t shift_numdigits; int shift_numbits; for (;;) { if (FIXNUM_P(y)) { long l = FIX2LONG(y); unsigned long shift; if (0 <= l) { lshift_p = 0; shift = l; } else { lshift_p = 1; shift = 1+(unsigned long)(-(l+1)); } shift_numbits = (int)(shift & (BITSPERDIG-1)); shift_numdigits = shift >> bit_length(BITSPERDIG-1); return bignorm(big_shift3(x, lshift_p, shift_numdigits, shift_numbits)); } else if (RB_BIGNUM_TYPE_P(y)) { return bignorm(big_shift2(x, 0, y)); } y = rb_to_int(y); } }
Bit Reference—Returns the nth bit in the (assumed) binary representation of big, where big is the least significant bit.
a = 9**15 50.downto(0) do |n| print a[n] end
produces:
000101110110100000111000011110010100111100010111001
static VALUE rb_big_aref(VALUE x, VALUE y) { BDIGIT *xds; unsigned long shift; long i, s1, s2; BDIGIT bit; if (RB_BIGNUM_TYPE_P(y)) { if (!RBIGNUM_SIGN(y)) return INT2FIX(0); bigtrunc(y); if (BIGSIZE(y) > sizeof(long)) { out_of_range: return RBIGNUM_SIGN(x) ? INT2FIX(0) : INT2FIX(1); } shift = big2ulong(y, "long"); } else { i = NUM2LONG(y); if (i < 0) return INT2FIX(0); shift = i; } s1 = shift/BITSPERDIG; s2 = shift%BITSPERDIG; bit = (BDIGIT)1 << s2; if (s1 >= RBIGNUM_LEN(x)) goto out_of_range; xds = BDIGITS(x); if (RBIGNUM_POSITIVE_P(x)) return (xds[s1] & bit) ? INT2FIX(1) : INT2FIX(0); if (xds[s1] & (bit-1)) return (xds[s1] & bit) ? INT2FIX(0) : INT2FIX(1); for (i = 0; i < s1; i++) if (xds[i]) return (xds[s1] & bit) ? INT2FIX(0) : INT2FIX(1); return (xds[s1] & bit) ? INT2FIX(1) : INT2FIX(0); }
Performs bitwise +exclusive or+ between big and numeric.
VALUE rb_big_xor(VALUE x, VALUE y) { VALUE z; BDIGIT *ds1, *ds2, *zds; long i, xn, yn, n1, n2; BDIGIT hibitsx, hibitsy; BDIGIT hibits1, hibits2; VALUE tmpv; BDIGIT tmph; long tmpn; if (!FIXNUM_P(y) && !RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bit(x, y, '^'); } hibitsx = abs2twocomp(&x, &xn); if (FIXNUM_P(y)) { return bigxor_int(x, xn, hibitsx, FIX2LONG(y)); } hibitsy = abs2twocomp(&y, &yn); if (xn > yn) { tmpv = x; x = y; y = tmpv; tmpn = xn; xn = yn; yn = tmpn; tmph = hibitsx; hibitsx = hibitsy; hibitsy = tmph; } n1 = xn; n2 = yn; ds1 = BDIGITS(x); ds2 = BDIGITS(y); hibits1 = hibitsx; hibits2 = hibitsy; z = bignew(n2, 0); zds = BDIGITS(z); for (i=0; i<n1; i++) { zds[i] = ds1[i] ^ ds2[i]; } for (; i<n2; i++) { zds[i] = hibitsx ^ ds2[i]; } twocomp2abs_bang(z, (hibits1 ^ hibits2) != 0); RB_GC_GUARD(x); RB_GC_GUARD(y); return bignorm(z); }
Returns the absolute value of big.
-1234567890987654321.abs #=> 1234567890987654321
static VALUE rb_big_abs(VALUE x) { if (!RBIGNUM_SIGN(x)) { x = rb_big_clone(x); RBIGNUM_SET_SIGN(x, 1); } return x; }
Returns the number of bits of the value of int.
“the number of bits” means that the bit position of the highest bit which is different to the sign bit. (The bit position of the bit 2**n is n+1.) If there is no such bit (zero or minus one), zero is returned.
I.e. This method returns ceil(log2(int < 0 ? -int : int+1)).
(-2**10000-1).bit_length #=> 10001 (-2**10000).bit_length #=> 10000 (-2**10000+1).bit_length #=> 10000 (-2**1000-1).bit_length #=> 1001 (-2**1000).bit_length #=> 1000 (-2**1000+1).bit_length #=> 1000 (2**1000-1).bit_length #=> 1000 (2**1000).bit_length #=> 1001 (2**1000+1).bit_length #=> 1001 (2**10000-1).bit_length #=> 10000 (2**10000).bit_length #=> 10001 (2**10000+1).bit_length #=> 10001
static VALUE rb_big_bit_length(VALUE big) { int nlz_bits; size_t numbytes; static const BDIGIT char_bit[1] = { CHAR_BIT }; BDIGIT numbytes_bary[bdigit_roomof(sizeof(size_t))]; BDIGIT nlz_bary[1]; BDIGIT result_bary[bdigit_roomof(sizeof(size_t)+1)]; numbytes = rb_absint_size(big, &nlz_bits); if (numbytes == 0) return LONG2FIX(0); if (RBIGNUM_NEGATIVE_P(big) && rb_absint_singlebit_p(big)) { if (nlz_bits != CHAR_BIT-1) { nlz_bits++; } else { nlz_bits = 0; numbytes--; } } if (numbytes <= SIZE_MAX / CHAR_BIT) { return SIZET2NUM(numbytes * CHAR_BIT - nlz_bits); } nlz_bary[0] = nlz_bits; bary_unpack(BARY_ARGS(numbytes_bary), &numbytes, 1, sizeof(numbytes), 0, INTEGER_PACK_NATIVE_BYTE_ORDER); BARY_SHORT_MUL(result_bary, numbytes_bary, char_bit); BARY_SUB(result_bary, result_bary, nlz_bary); return rb_integer_unpack(result_bary, numberof(result_bary), sizeof(BDIGIT), 0, INTEGER_PACK_LSWORD_FIRST|INTEGER_PACK_NATIVE_BYTE_ORDER); }
Returns an array with both a numeric
and a big
represented as Bignum objects.
This is achieved by converting numeric
to a Bignum.
A TypeError is raised if the
numeric
is not a Fixnum or Bignum type.
(0x3FFFFFFFFFFFFFFF+1).coerce(42) #=> [42, 4611686018427387904]
static VALUE rb_big_coerce(VALUE x, VALUE y) { if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (!RB_BIGNUM_TYPE_P(y)) { rb_raise(rb_eTypeError, "can't coerce %s to Bignum", rb_obj_classname(y)); } return rb_assoc_new(y, x); }
Performs integer division: returns integer value.
VALUE rb_big_idiv(VALUE x, VALUE y) { return rb_big_divide(x, y, rb_intern("div")); }
See Numeric#divmod
.
VALUE rb_big_divmod(VALUE x, VALUE y) { VALUE div, mod; if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (!RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bin(x, y, rb_intern("divmod")); } bigdivmod(x, y, &div, &mod); return rb_assoc_new(bignorm(div), bignorm(mod)); }
Returns true
only if obj is a Bignum
with the same value as big. Contrast this with
Bignum#==
, which performs type conversions.
68719476736.eql?(68719476736.0) #=> false
VALUE rb_big_eql(VALUE x, VALUE y) { if (!RB_BIGNUM_TYPE_P(y)) return Qfalse; if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y)) return Qfalse; if (RBIGNUM_LEN(x) != RBIGNUM_LEN(y)) return Qfalse; if (MEMCMP(BDIGITS(x),BDIGITS(y),BDIGIT,RBIGNUM_LEN(y)) != 0) return Qfalse; return Qtrue; }
Returns true
if big is an even number.
static VALUE rb_big_even_p(VALUE num) { if (RBIGNUM_LEN(num) != 0 && BDIGITS(num)[0] & 1) { return Qfalse; } return Qtrue; }
Returns the floating point result of dividing big by numeric.
-1234567890987654321.fdiv(13731) #=> -89910996357705.5 -1234567890987654321.fdiv(13731.24) #=> -89909424858035.7
VALUE rb_big_fdiv(VALUE x, VALUE y) { double dx, dy; dx = big2dbl(x); if (FIXNUM_P(y)) { dy = (double)FIX2LONG(y); if (isinf(dx)) return big_fdiv_int(x, rb_int2big(FIX2LONG(y))); } else if (RB_BIGNUM_TYPE_P(y)) { dy = rb_big2dbl(y); if (isinf(dx) || isinf(dy)) return big_fdiv_int(x, y); } else if (RB_FLOAT_TYPE_P(y)) { dy = RFLOAT_VALUE(y); if (isnan(dy)) return y; if (isinf(dx)) return big_fdiv_float(x, y); } else { return rb_num_coerce_bin(x, y, rb_intern("fdiv")); } return DBL2NUM(dx / dy); }
Compute a hash based on the value of big.
static VALUE rb_big_hash(VALUE x) { st_index_t hash; hash = rb_memhash(BDIGITS(x), sizeof(BDIGIT)*RBIGNUM_LEN(x)) ^ RBIGNUM_SIGN(x); return INT2FIX(hash); }
Returns the absolute value of big.
-1234567890987654321.abs #=> 1234567890987654321
static VALUE rb_big_abs(VALUE x) { if (!RBIGNUM_SIGN(x)) { x = rb_big_clone(x); RBIGNUM_SET_SIGN(x, 1); } return x; }
Returns big modulo other. See Numeric#divmod for more information.
VALUE rb_big_modulo(VALUE x, VALUE y) { VALUE z; if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (!RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bin(x, y, '%'); } bigdivmod(x, y, 0, &z); return bignorm(z); }
Returns true
if big is an odd number.
static VALUE rb_big_odd_p(VALUE num) { if (RBIGNUM_LEN(num) != 0 && BDIGITS(num)[0] & 1) { return Qtrue; } return Qfalse; }
Returns the remainder after dividing big by numeric.
-1234567890987654321.remainder(13731) #=> -6966 -1234567890987654321.remainder(13731.24) #=> -9906.22531493148
static VALUE rb_big_remainder(VALUE x, VALUE y) { VALUE z; if (FIXNUM_P(y)) { y = rb_int2big(FIX2LONG(y)); } else if (!RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bin(x, y, rb_intern("remainder")); } bigdivrem(x, y, 0, &z); return bignorm(z); }
Returns the number of bytes in the machine representation of big.
(256**10 - 1).size #=> 12 (256**20 - 1).size #=> 20 (256**40 - 1).size #=> 40
static VALUE rb_big_size(VALUE big) { return SIZET2NUM(BIGSIZE(big)); }
Converts big to a Float
. If big doesn't
fit in a Float
, the result is infinity.
static VALUE rb_big_to_f(VALUE x) { return DBL2NUM(rb_big2dbl(x)); }
Returns a string containing the representation of big radix base (2 through 36).
12345654321.to_s #=> "12345654321" 12345654321.to_s(2) #=> "1011011111110110111011110000110001" 12345654321.to_s(8) #=> "133766736061" 12345654321.to_s(16) #=> "2dfdbbc31" 78546939656932.to_s(36) #=> "rubyrules"
static VALUE rb_big_to_s(int argc, VALUE *argv, VALUE x) { int base; if (argc == 0) base = 10; else { VALUE b; rb_scan_args(argc, argv, "01", &b); base = NUM2INT(b); } return rb_big2str(x, base); }
Performs bitwise or
between big and numeric.
VALUE rb_big_or(VALUE x, VALUE y) { VALUE z; BDIGIT *ds1, *ds2, *zds; long i, xn, yn, n1, n2; BDIGIT hibitsx, hibitsy; BDIGIT hibits1, hibits2; VALUE tmpv; BDIGIT tmph; long tmpn; if (!FIXNUM_P(y) && !RB_BIGNUM_TYPE_P(y)) { return rb_num_coerce_bit(x, y, '|'); } hibitsx = abs2twocomp(&x, &xn); if (FIXNUM_P(y)) { return bigor_int(x, xn, hibitsx, FIX2LONG(y)); } hibitsy = abs2twocomp(&y, &yn); if (xn > yn) { tmpv = x; x = y; y = tmpv; tmpn = xn; xn = yn; yn = tmpn; tmph = hibitsx; hibitsx = hibitsy; hibitsy = tmph; } n1 = xn; n2 = yn; ds1 = BDIGITS(x); ds2 = BDIGITS(y); hibits1 = hibitsx; hibits2 = hibitsy; if (hibits1) n2 = n1; z = bignew(n2, 0); zds = BDIGITS(z); for (i=0; i<n1; i++) { zds[i] = ds1[i] | ds2[i]; } for (; i<n2; i++) { zds[i] = hibits1 | ds2[i]; } twocomp2abs_bang(z, hibits1 || hibits2); RB_GC_GUARD(x); RB_GC_GUARD(y); return bignorm(z); }
Inverts the bits in big. As Bignums are conceptually infinite length, the result acts as if it had an infinite number of one bits to the left. In hex representations, this is displayed as two periods to the left of the digits.
sprintf("%X", ~0x1122334455) #=> "..FEEDDCCBBAA"
static VALUE rb_big_neg(VALUE x) { VALUE z = rb_big_clone(x); BDIGIT *ds = BDIGITS(z); long n = RBIGNUM_LEN(z); if (!n) return INT2FIX(-1); if (RBIGNUM_POSITIVE_P(z)) { if (bary_add_one(ds, n)) { big_extend_carry(z); } RBIGNUM_SET_NEGATIVE_SIGN(z); } else { bary_neg(ds, n); if (bary_add_one(ds, n)) return INT2FIX(-1); bary_neg(ds, n); RBIGNUM_SET_POSITIVE_SIGN(z); } return bignorm(z); }