Class: Decimal

Inherits:
Numeric
  • Object
show all
Defined in:
decimal.c

Defined Under Namespace

Classes: ArithmeticError, DomainError

Constant Summary collapse

INFINITY =

represents +Infinity.

VALUE_PINF
NAN =

represents NaN. (Not a Number)

VALUE_NaN
ROUND_CEILING = 
ROUND_CEILING
ROUND_DOWN = 
ROUND_DOWN
ROUND_FLOOR = 
ROUND_FLOOR
ROUND_HALF_DOWN = 
ROUND_HALF_DOWN
ROUND_HALF_EVEN = 
ROUND_HALF_EVEN
ROUND_HALF_UP = 
ROUND_HALF_UP
ROUND_UP = 
ROUND_UP
ROUND_UNNECESSARY = 
ROUND_UNNECESSARY

Instance Method Summary collapse

Constructor Details

#new(arg) ⇒ Object

Returns a new decimal made from arg. The arg must be an Integer or a String. An acceptable format of String is equal to Kernel.Float()‘s one. In a Regexp, it should be:

digits  = /(\d+_)*\d+/
number  = /(\+-)?#{digits}/
body    = /#{number}(\.#{digits})?([eE]#{number})?/
decimal = /\A\s*#{body}\s*\z/

And its samples are:

Decimal(1)                  #=> Decimal(1)
Decimal(2**64)              #=> Decimal(18446744073709551616)
Decimal("1")                #=> Decimal(1)
Decimal("1.1")              #=> Decimal(1.1)
Decimal("1e10")             #=> Decimal(10000000000)
Decimal("299_792_458")      #=> Decimal(299792458)
Decimal("2.99_792_458e8")   #=> Decimal(299792458)

Notice that a Float is not acceptable for arg to keep exactness.

Decimal.new(1.1)            #=> (ArgumentError)



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# File 'decimal.c', line 296

static VALUE
dec_initialize(VALUE self, VALUE arg)
{
    if (DECIMAL_P(arg)) {
	return arg;
    }
    DATA_PTR(self) = create_dec(arg);
    return self;
}

Instance Method Details

#%(other) ⇒ Object #modulo(other) ⇒ Object

Return the modulo after division of dec by other.

Decimal("6543.21").modulo(137)                 #=> Decimal(104.21)
Decimal("6543.21").modulo(Decimal("137.24"))   #=> Decimal(92.9299999999996)



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# File 'decimal.c', line 1105

static VALUE
dec_mod(VALUE x, VALUE y)
{
    Decimal *a, *b;
    VALUE mod;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, '%');
    }
    GetDecimal(x, a);
    divmod(a, b, NULL, &mod);
    return mod;
}

#*(other) ⇒ Object

Returns a new decimal which is the product of dec and other.



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# File 'decimal.c', line 718

static VALUE
dec_mul(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
        /* TODO: can be optimized if y = 0, 1 or -1 */
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
        break;
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, '*');
    }
    GetDecimal(x, a);

    if (DEC_ISINF(a)) {
	if (DEC_ISINF(b)) return x == y ? VALUE_PINF : VALUE_NINF;
	if (DEC_ZERO_P(b)) return VALUE_NaN;
	if (!INUM_NEGATIVE_P(b->inum)) return x;
	return dec_uminus(x);
    }
    if (DEC_ZERO_P(a)) {
	if (DEC_ISINF(b)) return VALUE_NaN;
	if (DEC_ZERO_P(b))  {
	    return a->inum == DEC_PZERO ? y : dec_uminus(y);
	}
	if (INUM_NEGATIVE_P(b->inum)) return dec_uminus(x);
	return x;
    }
    if (DEC_IMMEDIATE_P(b) || DEC_ZERO_P(b)) {
        if (INUM_NEGATIVE_P(a->inum)) return dec_uminus(y);
        return y;
    }
    return WrapDecimal(normal_mul(a, b));
}

#**(fix) ⇒ Object

WARNING: The behavior of this method may change.

Raises dec the fix power.



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# File 'decimal.c', line 1352

static VALUE
dec_pow(VALUE x, VALUE y)
{
    return dec_power(1, &y, x);
}

#+(other) ⇒ Object

Returns a new decimal which is the sum of dec and other.



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# File 'decimal.c', line 599

static VALUE
dec_plus(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
	break;
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, '+');
    }

    if (DEC_VALUE_ISINF(x)) {
	if (DEC_VALUE_ISINF(y) && x != y) return VALUE_NaN;
	return x;
    }
    if (DEC_VALUE_ISINF(y)) return y;
    /* now, x and y are not NaN nor +-INFINITY */
    GetDecimal(x, a);
    if (DEC_ZERO_P(a)) {
	VALUE inum;

        if (DEC_ZERO_P(b)) {
	    const long scale = MAX(a->scale, b->scale);

            if (a->inum == DEC_NZERO && b->inum == DEC_NZERO)
		return dec_nzero(scale);
            return dec_pzero(scale);
        }
	if (a->scale <= b->scale)
	    return y;
	inum = inum_lshift(b->inum, a->scale - b->scale);
	return WrapDecimal(dec_raw_new(inum, a->scale));
    }
    if (DEC_ZERO_P(b)) {
	VALUE inum;
	
	if (a->scale >= b->scale)
	    return x;
	inum = inum_lshift(a->inum, b->scale - a->scale);
	return WrapDecimal(dec_raw_new(inum, b->scale));
    }
    /* "true" means addition */
    return WrapDecimal(normal_plus(a, b, Qtrue));
}

#-(other) ⇒ Object

Returns a new float which is the difference of dec and other.



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# File 'decimal.c', line 664

static VALUE
dec_minus(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
	break;
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, '-');
    }
    if (DEC_VALUE_ISINF(x)) {
	if (x == y) return VALUE_NaN;
	return x;
    }
    if (DEC_VALUE_ISINF(y)) return NEGATE_INF(y);

    GetDecimal(x, a);
    if (DEC_ZERO_P(a)) { /* FIXME: needs refactoring */
	if (!DEC_ISINF(b) && DEC_ZERO_P(b) && a->inum == b->inum) {
	     /* FIXME: UNDER CONSTRUCTION for scaling */
	    return dec_pzero(MAX(a->scale, b->scale));
	}
	return dec_uminus(y);
    }
    if (DEC_ZERO_P(b)) return x;
    /* "false" means subtraction */
    return WrapDecimal(normal_plus(a, b, Qfalse));
}

#- ⇒ Object

Returns a negated value of dec.



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# File 'decimal.c', line 533

static VALUE
dec_uminus(VALUE num)
{
    VALUE inum;
    Decimal *d;

    CHECK_NAN(num);
    if (num == VALUE_PINF) return VALUE_NINF;
    if (num == VALUE_NINF) return VALUE_PINF;

    GetDecimal(num, d);
    if (d->inum == DEC_PZERO)
	inum = DEC_NZERO;
    else if (d->inum == DEC_NZERO)
	inum = DEC_PZERO;
    else
	inum = INUM_UMINUS(d->inum);
    return WrapDecimal(dec_raw_new(inum, d->scale));
}

#/(y) ⇒ Object

:nodoc:



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# File 'decimal.c', line 1002

static VALUE
dec_div(VALUE x, VALUE y)
{
    return dec_divide(1, &y, x);
}

#<(other) ⇒ Boolean

Returns true if dec is less than other.

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1540

static VALUE
dec_lt(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_cmperr(x, y);
        return Qnil; /* not reached */
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_relop(x, y, '<');
    }
    return cmp(a, b) < 0 ? Qtrue : Qfalse;
}

#<=(other) ⇒ Boolean

Returns true if dec is less than or equal to other.

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1573

static VALUE
dec_le(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_cmperr(x, y);
        return Qnil; /* not reached */
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_relop(x, y, rb_intern("<="));
    }
    return cmp(a, b) <= 0 ? Qtrue : Qfalse;
}

#<=>(other) ⇒ -1, ...

Returns -1, 0, or +1 depending on whether dec is less than, equal to, or greater than other. This is the basis for the tests in Comparable.

Returns:

  • (-1, 0, +1) 


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# File 'decimal.c', line 1442

static VALUE
dec_cmp(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qnil);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	return Qnil;
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_cmp(x, y, rb_intern("<=>"));
    }
    return INT2FIX(cmp(a, b));
}

#==(other) ⇒ Boolean

Returns true only if other has the same value as dec. Contrast this with eql?, which requires other to be the same class, a Decimal.

Decimal(1) == 1                #=> true
Decimal(1) == Decimal("1.0")   #=> true
Decimal(1) == 1.0              #=> false

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1408

static VALUE
dec_eq(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	return Qfalse;
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return RTEST(rb_num_coerce_cmp(x, y, rb_intern("==")));
    }
    return cmp(a, b) == 0 ? Qtrue : Qfalse;
}

#>(other) ⇒ Boolean

Returns true if dec is greater than other.

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1474

static VALUE
dec_gt(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_cmperr(x, y);
        return Qnil; /* not reached */
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_relop(x, y, '>');
    }
    return cmp(a, b) > 0 ? Qtrue : Qfalse;
}

#>=(other) ⇒ Boolean

Returns true if dec is greater than or equal to other.

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1507

static VALUE
dec_ge(VALUE x, VALUE y)
{
    Decimal *a, *b;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    GetDecimal(x, a);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_cmperr(x, y);
        return Qnil; /* not reached */
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_relop(x, y, rb_intern(">="));
    }
    return cmp(a, b) >= 0 ? Qtrue : Qfalse;
}

#abs ⇒ Object

Returns the absolute value of dec.

Decimal("34.56").abs    #=> Decimal(34.56)
Decimal("-34.56").abs   #=> Decimal(34.56)



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# File 'decimal.c', line 1777

static VALUE
dec_abs(VALUE num)
{
    Decimal *d;
    VALUE inum;

    CHECK_NAN(num);
    if (DEC_VALUE_ISINF(num))
	return VALUE_PINF;
    GetDecimal(num, d);
    if (d->inum == DEC_PZERO ||
	(d->inum != DEC_NZERO && !INUM_NEGATIVE_P(d->inum))) {
	return num;
    }
    inum = (d->inum == DEC_NZERO) ? DEC_PZERO : INUM_UMINUS(d->inum);
    return WrapDecimal(dec_raw_new(inum, d->scale));
}

#ceil(n = 0) ⇒ Integer

Returns the smallest Integer greater than or equal to dec.

Decimal("1.2").ceil    #=> 2
Decimal("2.0").ceil    #=> 2
Decimal("-1.2").ceil   #=> -1
Decimal("-2.0").ceil   #=> -2

This is identical to dec.round(n, Decimal::ROUND_CEILING). See Decimal#round for more details.

Returns:

  • (Integer) 


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# File 'decimal.c', line 1896

static VALUE
dec_ceil(int argc, VALUE *argv, VALUE x)
{
    return rounding_method(argc, argv, x, ROUND_CEILING);
}

#coerce(other) ⇒ Array

Returns array [Decimal(other), dec] if other has a compatible type, Integer or Decimal. Otherwise raises a TypeError.

Decimal(1).coerce(2)            #=> [Decimal(2), Decimal(1)]
Decimal(1).coerce(Decimal(2))   #=> [Decimal(2), Decimal(1)]
Decimal(1).coerce(2.5)          #=> (TypeError)

Returns:

  • (Array) 


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# File 'decimal.c', line 502

static VALUE
dec_coerce(VALUE x, VALUE y)
{
    VALUE yy;

    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	yy = WrapDecimal(inum_to_dec(y));
	return rb_assoc_new(yy, x);
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't coerce Float to Decimal; "
		 "use Decimal#to_f explicitly if needed");
	break;
      case T_DATA:
	if (DECIMAL_P(y)) return rb_assoc_new(y, x);
	/* fall through */
      default:
	rb_raise(rb_eTypeError, "can't coerce %s to Decimal",
		 rb_obj_classname(y));
	break;
    }
    return Qnil; /* not reached */
}

#div(y) ⇒ Object

:nodoc:



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# File 'decimal.c', line 1067

static VALUE
dec_idiv(VALUE x, VALUE y)
{
    Decimal *a, *b;
    VALUE div;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, rb_intern("div"));
    }
    GetDecimal(x, a);
    divmod(a, b, &div, NULL);
    return div;
}

#divide(other, scale = 0, mode = Decimal::ROUND_UNNECESSARY) ⇒ Object

WARNING: The behavior of this method may change.

Returns a new decimal which is the result of dividing dec by other.

FIXME: write details



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# File 'decimal.c', line 914

static VALUE
dec_divide(int argc, VALUE *argv, VALUE x)
{
    VALUE y;
    Decimal *a, *b;
    VALUE mode = ROUND_UNNECESSARY;
    long l, scale = 0; /* FIXME: dummy 0 */
    VALUE vscale, vmode;

    CHECK_NAN(x);
    GetDecimal(x, a);

    rb_scan_args(argc, argv, "12", &y, &vscale, &vmode);
    switch (argc) {
      case 3:
	Check_Type(vmode, T_SYMBOL);
	if (!valid_rounding_mode_p(vmode)) {
	    rb_raise(rb_eArgError, "invalid rounding mode %s",
                     RSTRING_PTR(rb_inspect(vmode)));
	}
	mode = vmode;
	/* fall through */
      case 2:
	scale = NUM2LONG(vscale);
	break;
      case 1:
	if (mode != ROUND_UNNECESSARY) {
	    rb_raise(rb_eArgError, "scale number argument needed");
	}
    }
    CHECK_NAN(y);

    switch (TYPE(y)) {
      case T_FIXNUM:
        l = FIX2LONG(y);
        if (l == 0) {
            if (DEC_ISINF(a)) return x;
            if (DEC_ZERO_P(a)) return VALUE_NaN;
            return INUM_NEGATIVE_P(a->inum) ? VALUE_NINF : VALUE_PINF;
        }
        else if (l == 1) return x;
        else if (l == -1) return dec_uminus(x);
	/* fall through */
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
        return Qnil; /* not reached */
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
        return rb_num_coerce_bin(x, y, rb_intern("divide"));
    }

    if (DEC_ISINF(a)) {
	if (DEC_ISINF(b)) return VALUE_NaN;
	if (b->inum == DEC_PZERO) return x;
	if (b->inum == DEC_NZERO) return NEGATE_INF(x);
	return INUM_NEGATIVE_P(b->inum) ? NEGATE_INF(x) : x;
    }
    if (DEC_ZERO_P(a)) {
	if (b == DEC_PINF) return x;
	if (b == DEC_NINF) return dec_uminus(x);
	if (INUM_SPZERO_P(b->inum)) return VALUE_NaN;
	return INUM_NEGATIVE_P(b->inum) ? dec_uminus(x) : x;
    }
    if (DEC_ISINF(b)) {
	if (INUM_NEGATIVE_P(a->inum) == (b == DEC_NINF)) {
	    return dec_pzero(0); /* FIXME for scaling */
	}
	return dec_nzero(0); /* FIXME for scaling */
    }
    if (DEC_ZERO_P(b)) {
	if (INUM_NEGATIVE_P(a->inum) == (b->inum == DEC_NZERO)) {
	    return VALUE_PINF;
	}
	return VALUE_NINF;
    }
    return WrapDecimal(normal_divide(a, b, scale, mode));
}

#divmod(other) ⇒ Array

Returns an array containing the quotient and modulus obtained by dividing dec by other.

Decimal(11).divmod(3)                    #=> [3, Decimal(2)]
Decimal(11).divmod(-3)	                #=> [-4, Decimal(-1)]
Decimal(11).divmod(Decimal("3.5"))       #=> [3, Decimal(0.5)]
Decimal(-11).divmod(Decimal("3.5"))      #=> [-4, Decimal(3.0)]
Decimal("11.5").divmod(Decimal("3.5"))   #=> [3, Decimal(1.0)]

See Numeric#divmod for more details.

Returns:

  • (Array) 


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# File 'decimal.c', line 1148

static VALUE
dec_divmod(VALUE x, VALUE y)
{
    Decimal *a, *b;
    VALUE div, mod;

    CHECK_NAN2_WITH_VAL(x, y, rb_assoc_new(VALUE_NaN, VALUE_NaN));
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, rb_intern("divmod"));
    }
    GetDecimal(x, a);
    divmod(a, b, &div, &mod);
    return rb_assoc_new(div, mod);
}

#eql?(other) ⇒ Boolean

Returns true if other is a Decimal and is equal to dec including their values of scale.

Decimal(1) == 1                    #=> true
Decimal(1).eql?(1)                 #=> false
Decimal(1).eql?(Decimal(1))        #=> true
Decimal(1).eql?(Decimal("1.0")))   #=> false

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1612

static VALUE
dec_eql(VALUE x, VALUE y)
{
    Decimal *a, *b;

    if (TYPE(y) != T_DATA || !DECIMAL_P(y))
	return Qfalse;

    CHECK_NAN2_WITH_VAL(x, y, Qfalse);
    if (DEC_VALUE_ISINF(x) || DEC_VALUE_ISINF(y))
	return x == y ? Qtrue : Qfalse;

    GetDecimal(x, a);
    GetDecimal(y, b);
    if (a->scale != b->scale)
	return Qfalse;
    if (a->inum == b->inum)
	return Qtrue;
    if (INUM_SPZERO_P(a->inum) || INUM_SPZERO_P(b->inum))
	return Qfalse;
    if (INUM_EQ(a->inum, b->inum))
	return Qtrue;
    return Qfalse;
}

#finite? ⇒ Boolean

Returns true if dec is a finite number (it is not infinite nor NaN).

Decimal(0).finite?             #=> true
Decimal(1).divide(0).finite?   #=> false
Decimal(0).divide(0).finite?   #=> false

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1976

static VALUE
dec_finite_p(VALUE num)
{
    if (!DEC_VALUE_ISINF(num) && num != VALUE_NaN) {
	return Qtrue;
    }
    return Qfalse;
}

#floor(n = 0) ⇒ Integer

Returns the largest integer less than or equal to dec.

Decimal("1.2").floor    #=> 1
Decimal("2.0").floor    #=> 2
Decimal("-1.2").floor   #=> -2
Decimal("-2.0").floor   #=> -2

This is identical to dec.round(n, Decimal::ROUND_FLOOR). See Decimal#round for more details.

Returns:

  • (Integer) 


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# File 'decimal.c', line 1876

static VALUE
dec_floor(int argc, VALUE *argv, VALUE x)
{
    return rounding_method(argc, argv, x, ROUND_FLOOR);
}

#hash ⇒ Integer

Returns a hash code for dec.

Returns:

  • (Integer) 


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# File 'decimal.c', line 1643

static VALUE
dec_hash(VALUE x)
{
    Decimal *d;
    long hash;

    GetDecimal(x, d);
    if (!DEC_IMMEDIATE_P(d)) {
        VALUE inum = d->inum; 

        if (INUM_SPZERO_P(inum)) inum = INT2FIX(0);
        hash = NUM2LONG(INUM_HASH(inum));
	hash ^= d->scale;
    }
    else hash = (long)d;
    return LONG2NUM(hash);
}

#infinite? ⇒ nil, ...

Returns nil, -1, or 1 depending on whether dec is finite, -infinity, or infinity.

Decimal(0).infinite?              #=> nil
Decimal(-1).divide(0).infinite?   #=> -1
Decimal(+1).divide(0).infinite?   #=> 1

Returns:

  • (nil, -1, +1) 


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# File 'decimal.c', line 1996

static VALUE
dec_infinite_p(VALUE num)
{
    if (num == VALUE_PINF) return INT2FIX(1);
    if (num == VALUE_NINF) return INT2FIX(-1);
    return Qnil;
}

#inspect ⇒ String

Returns a easy-to-distinguish string: "Decimal(#{dec})".

Decimal(1).inspect             #=> "Decimal(1)"
Decimal("1.1").inspect         #=> "Decimal(1.1)"
Decimal::INFINITY.inspect   #=> "Decimal(Infinity)"

Returns:

  • (String) 


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# File 'decimal.c', line 474

static VALUE
dec_inspect(VALUE self)
{
    char *s;
    VALUE str, newstr;
    long len;

    str = dec_to_s(self);
    len = 9 + RSTRING_LEN(str); /* 9 == strlen("Decimal()") */
    s = ALLOC_N(char, len + 1); /* +1 for NUL */
    sprintf(s, "Decimal(%s)", RSTRING_PTR(str));
    newstr = rb_usascii_str_new(s, len);
    xfree(s);
    return newstr;
}

#%(other) ⇒ Object #modulo(other) ⇒ Object

Return the modulo after division of dec by other.

Decimal("6543.21").modulo(137)                 #=> Decimal(104.21)
Decimal("6543.21").modulo(Decimal("137.24"))   #=> Decimal(92.9299999999996)



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# File 'decimal.c', line 1105

static VALUE
dec_mod(VALUE x, VALUE y)
{
    Decimal *a, *b;
    VALUE mod;

    CHECK_NAN2(x, y);
    switch (TYPE(y)) {
      case T_FIXNUM:
      case T_BIGNUM:
	b = inum_to_dec(y);
	break;
      case T_FLOAT:
	rb_raise(rb_eTypeError, "can't operate with Float");
      case T_DATA:
	if (DECIMAL_P(y)) {
	    GetDecimal(y, b);
	    break;
	}
	/* fall through */
      default:
	return rb_num_coerce_bin(x, y, '%');
    }
    GetDecimal(x, a);
    divmod(a, b, NULL, &mod);
    return mod;
}

#nan? ⇒ Boolean

Returns true if dec is an invalid point number, NaN.

Decimal(-1).nan?            #=> false
Decimal(1).divide(0).nan?   #=> false
Decimal(0).divide(0).nan?   #=> true

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1959

static VALUE
dec_nan_p(VALUE num)
{
    return num == VALUE_NaN;
}

#power(*args) ⇒ Object

:nodoc:



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# File 'decimal.c', line 1312

static VALUE
dec_power(int argc, VALUE *argv, VALUE x)
{
    VALUE mode = ROUND_UNNECESSARY;
    VALUE y, scale, vmode;

    rb_scan_args(argc, argv, "12", &y, &scale, &vmode);
    switch (argc) {
      case 3:
        Check_Type(vmode, T_SYMBOL);
	if (!valid_rounding_mode_p(vmode)) {
	    rb_raise(rb_eArgError, "invalid rounding mode %s",
                     RSTRING_PTR(rb_inspect(vmode)));
	}
	mode = vmode;
	/* fall through */
    case 2:
        Check_Type(scale, T_FIXNUM);
        break;
    case 1:
	if (mode != ROUND_UNNECESSARY) {
	    rb_raise(rb_eArgError, "scale number argument needed");
	}
    }

    if (!FIXNUM_P(y) && !DECIMAL_P(y)) {
        rb_raise(rb_eTypeError, "2nd argument %s must be Fixnum or Decimal",
                 RSTRING_PTR(rb_inspect(y)));
    }
    return power_body(x, y, scale, mode);
}

#round(n = 0, mode = Decimal::ROUND_HALF_UP) ⇒ Integer

FIXME: more examples

Rounds dec to a given precision n in decimal digits (default 0 digits) with rounding mode mode. Precision may be negative. Returns a Decimal when n is greater than 0, Integer otherwise.

Decimal("1.5").round    #=> 2
Decimal("-1.5").round   #=> -2

Returns:

  • (Integer) 


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# File 'decimal.c', line 1915

static VALUE
dec_round(int argc, VALUE *argv, VALUE x)
{
    Decimal *d;
    VALUE vscale, mode;
    long scale = 0;

    rb_scan_args(argc, argv, "02", &vscale, &mode);
    switch (argc) {
      case 2:
	Check_Type(mode, T_SYMBOL);
	if (!valid_rounding_mode_p(mode)) {
	    rb_raise(rb_eArgError, "invalid rounding mode %s",
                     RSTRING_PTR(rb_inspect(mode)));
	}
	/* fall through */
      case 1:
	scale = NUM2LONG(vscale);
	/* fall through */
      default:
        if (NIL_P(mode)) mode = ROUND_HALF_UP;
	break;
    }
    GetDecimal(x, d);
    if (scale <= 0) {
	VALUE inum;

	do_round(d, scale, mode, &inum);
	return inum;
    }
    return WrapDecimal(do_round(d, scale, mode, NULL));
}

#scale ⇒ Object

:nodoc:



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# File 'decimal.c', line 326

static VALUE
dec_scale(VALUE self)
{
    Decimal *d;

    GetDecimal(self, d);
    if (DEC_IMMEDIATE_P(d)) return Qnil;
    return LONG2NUM(d->scale);
}

#strip ⇒ Object

:nodoc:



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# File 'decimal.c', line 348

static VALUE
dec_strip_trailing_zeros(VALUE self)
{
    Decimal *d, *d2;

    GetDecimal(self, d);
    if (DEC_IMMEDIATE_P(d))
	return self;
    if (DEC_ZERO_P(d)) { /* XXX: negative scale? */
        if (d->scale <= 0) return self;
	d2 = finite_dup(d);
	d2->scale = 0;
	return WrapDecimal(d2);
    }
    d2 = finite_dup(d);
    /* TODO: can be optimized with dividing each part
     * for Bignums and Fixnums */
    while (INUM_BOTTOMDIG(d2->inum) == 0) {
	d2->inum = INUM_DIV(d2->inum, INT2FIX(10));
	d2->scale--;
    }
    return WrapDecimal(d2);
}

#strip_trailing_zeros ⇒ Object

:nodoc:



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# File 'decimal.c', line 348

static VALUE
dec_strip_trailing_zeros(VALUE self)
{
    Decimal *d, *d2;

    GetDecimal(self, d);
    if (DEC_IMMEDIATE_P(d))
	return self;
    if (DEC_ZERO_P(d)) { /* XXX: negative scale? */
        if (d->scale <= 0) return self;
	d2 = finite_dup(d);
	d2->scale = 0;
	return WrapDecimal(d2);
    }
    d2 = finite_dup(d);
    /* TODO: can be optimized with dividing each part
     * for Bignums and Fixnums */
    while (INUM_BOTTOMDIG(d2->inum) == 0) {
	d2->inum = INUM_DIV(d2->inum, INT2FIX(10));
	d2->scale--;
    }
    return WrapDecimal(d2);
}

#to_f ⇒ Float

Converts dec to a Float. Note that this may lose some precision and/or exactness. If you want to operate Decimal with Float, use this method explicitly.

Returns:

  • (Float) 


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# File 'decimal.c', line 1743

static VALUE
dec_to_f(VALUE num)
{
    Decimal *d;
    double f;

    CHECK_NAN_WITH_VAL(num, rb_float_new(NAN));
    if (num == VALUE_PINF)
	return rb_float_new(INFINITY);
    if (num == VALUE_NINF)
	return rb_float_new(-INFINITY);

    GetDecimal(num, d);
    if (d->inum == DEC_PZERO)
	f = 0.0;
    else if (d->inum == DEC_NZERO)
	f = -0.0;
    else if (out_of_double_range_p(d, &f))
	rb_warning("Decimal out of Float range");
    else
	f = normal_to_f(d);

    return rb_float_new(f);
}

#to_i ⇒ Integer

Returns dec truncated to an Integer.

Returns:

  • (Integer) 


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# File 'decimal.c', line 1819

static VALUE
dec_to_i(VALUE num)
{
   Decimal *d;
   VALUE inum;

   GetDecimal(num, d);
   do_round(d, 0, ROUND_DOWN, &inum); /* equal to "d.round(0, :down)" */
   return inum;
}

#to_s ⇒ String

WARNING: The behavior of this method may change.

Returns a string containing a simple representation of self.

Decimal(1).to_s             #=> "1"
Decimal("1.1").to_s         #=> "1.1"
Decimal::INFINITY.to_s   #=> "Infinity"

Returns:

  • (String) 


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# File 'decimal.c', line 435

static VALUE
dec_to_s(VALUE self)
{
    Decimal *d;

    CHECK_NAN_WITH_VAL(self, rb_usascii_str_new_cstr("NaN"));
    if (self == VALUE_PINF) return rb_usascii_str_new_cstr("Infinity");
    if (self == VALUE_NINF) return rb_usascii_str_new_cstr("-Infinity");
    GetDecimal(self, d);
    if (DEC_ZERO_P(d)) {
	const size_t HEAD_LEN = d->inum == DEC_PZERO ? 2U : 3U; /* "-0.".length */
	long len = HEAD_LEN + d->scale;
	char *buf;

	/* FIXME: use "0eN" style when the scale is negative? */
	if (d->scale <= 0) /* ignore the case of negative scale */
	    return d->inum == DEC_PZERO ?
	      rb_usascii_str_new_cstr("0") : rb_usascii_str_new_cstr("-0");
	buf = xmalloc(len);
	if (d->inum == DEC_PZERO)
	    memcpy(buf, "0.", HEAD_LEN);
	else
	    memcpy(buf, "-0.", HEAD_LEN);
	memset(buf + HEAD_LEN, '0', d->scale);
	return rb_usascii_str_new(buf, len);
    }
    return finite_to_s(d);
}

#truncate(n = 0) ⇒ Integer

Returns dec truncated to an Integer.

This is identical to dec.round(n, Decimal::ROUND_DOWN). See Decimal#round for more details.

Returns:

  • (Integer) 


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# File 'decimal.c', line 1856

static VALUE
dec_truncate(int argc, VALUE *argv, VALUE x)
{
    return rounding_method(argc, argv, x, ROUND_DOWN);
}

#unscaled_value ⇒ Object

:nodoc:



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# File 'decimal.c', line 337

static VALUE
dec_unscaled_value(VALUE self)
{
    Decimal *d;

    GetDecimal(self, d);
    if (DEC_IMMEDIATE_P(d)) return Qnil;
    return DEC_ZERO_P(d) ? INT2FIX(0) : d->inum;
}

#zero? ⇒ Boolean

Returns true if dec is zero.

Returns:

  • (Boolean) 


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# File 'decimal.c', line 1801

static VALUE
dec_zero_p(VALUE num)
{
    Decimal *d;

    GetDecimal(num, d);
    if (!DEC_IMMEDIATE_P(d) && DEC_ZERO_P(d)) {
        return Qtrue;
    }
    return Qfalse;
}