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BigDecimal provides arbitrary-precision floating point decimal arithmetic.

Introduction

Ruby provides built-in support for arbitrary precision integer arithmetic.

For example:

42**13  #=>   1265437718438866624512

BigDecimal provides similar support for very large or very accurate floating point numbers.

Decimal arithmetic is also useful for general calculation, because it provides the correct answers people expect–whereas normal binary floating point arithmetic often introduces subtle errors because of the conversion between base 10 and base 2.

For example, try:

sum = 0
10_000.times do
  sum = sum + 0.0001
end
print sum #=> 0.9999999999999062

and contrast with the output from:

require 'bigdecimal'

sum = BigDecimal("0")
10_000.times do
  sum = sum + BigDecimal("0.0001")
end
print sum #=> 0.1E1

Similarly:

(BigDecimal("1.2") - BigDecimal("1.0")) == BigDecimal("0.2") #=> true

(1.2 - 1.0) == 0.2 #=> false

A Note About Precision

For a calculation using a BigDecimal and another value, the precision of the result depends on the type of value:

  • If value is a Float, the precision is Float::DIG + 1.

  • If value is a Rational, the precision is larger than Float::DIG + 1.

  • If value is a BigDecimal, the precision is value‘s precision in the internal representation, which is platform-dependent.

  • If value is other object, the precision is determined by the result of +BigDecimal(value)+.

Special features of accurate decimal arithmetic

Because BigDecimal is more accurate than normal binary floating point arithmetic, it requires some special values.

Infinity

BigDecimal sometimes needs to return infinity, for example if you divide a value by zero.

BigDecimal("1.0") / BigDecimal("0.0")  #=> Infinity
BigDecimal("-1.0") / BigDecimal("0.0")  #=> -Infinity

You can represent infinite numbers to BigDecimal using the strings 'Infinity', '+Infinity' and '-Infinity' (case-sensitive)

Not a Number

When a computation results in an undefined value, the special value NaN (for ‘not a number’) is returned.

Example:

BigDecimal("0.0") / BigDecimal("0.0") #=> NaN

You can also create undefined values.

NaN is never considered to be the same as any other value, even NaN itself:

n = BigDecimal('NaN')
n == 0.0 #=> false
n == n #=> false

Positive and negative zero

If a computation results in a value which is too small to be represented as a BigDecimal within the currently specified limits of precision, zero must be returned.

If the value which is too small to be represented is negative, a BigDecimal value of negative zero is returned.

BigDecimal("1.0") / BigDecimal("-Infinity") #=> -0.0

If the value is positive, a value of positive zero is returned.

BigDecimal("1.0") / BigDecimal("Infinity") #=> 0.0

(See BigDecimal.mode for how to specify limits of precision.)

Note that -0.0 and 0.0 are considered to be the same for the purposes of comparison.

Note also that in mathematics, there is no particular concept of negative or positive zero; true mathematical zero has no sign.

bigdecimal/util

When you require bigdecimal/util, the to_d method will be available on BigDecimal and the native Integer, Float, Rational, and String classes:

require 'bigdecimal/util'

42.to_d         # => 0.42e2
0.5.to_d        # => 0.5e0
(2/3r).to_d(3)  # => 0.667e0
"0.5".to_d      # => 0.5e0

Methods for Working with JSON

  • ::json_create: Returns a new BigDecimal object constructed from the given object.

  • #as_json: Returns a 2-element hash representing self.

  • #to_json: Returns a JSON string representing self.

These methods are provided by the JSON gem. To make these methods available:

require 'json/add/bigdecimal'

  • License

Copyright © 2002 by Shigeo Kobayashi <shigeo@tinyforest.gr.jp>.

BigDecimal is released under the Ruby and 2-clause BSD licenses. See LICENSE.txt for details.

Maintained by mrkn <mrkn@mrkn.jp> and ruby-core members.

Documented by zzak <zachary@zacharyscott.net>, mathew <meta@pobox.com>, and many other contributors.

Methods
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A
C
D
E
F
H
I
J
L
M
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P
Q
R
S
T
Z

Constants

BASE = INT2FIX((SIGNED_VALUE)VpBaseVal())
 

Base value used in internal calculations. On a 32 bit system, BASE is 10000, indicating that calculation is done in groups of 4 digits. (If it were larger, BASE**2 wouldn’t fit in 32 bits, so you couldn’t guarantee that two groups could always be multiplied together without overflow.)
EXCEPTION_ALL = 0xff
 

Determines whether overflow, underflow or zero divide result in an exception being thrown. See BigDecimal.mode.
EXCEPTION_INFINITY = 0x01
 

Determines what happens when the result of a computation is infinity. See BigDecimal.mode.
EXCEPTION_NaN = 0x02
 

Determines what happens when the result of a computation is not a number (NaN). See BigDecimal.mode.
EXCEPTION_OVERFLOW = 0x01
 

Determines what happens when the result of a computation is an overflow (a result too large to be represented). See BigDecimal.mode.
EXCEPTION_UNDERFLOW = 0x04
 

Determines what happens when the result of a computation is an underflow (a result too small to be represented). See BigDecimal.mode.
EXCEPTION_ZERODIVIDE = 0x10
 

Determines what happens when a division by zero is performed. See BigDecimal.mode.
INFINITY = BIGDECIMAL_POSITIVE_INFINITY
 

Special value constants
NAN = BIGDECIMAL_NAN
 
ROUND_CEILING = 5
 

Round towards +Infinity. See BigDecimal.mode.
ROUND_DOWN = 2
 

Indicates that values should be rounded towards zero. See BigDecimal.mode.
ROUND_FLOOR = 6
 

Round towards -Infinity. See BigDecimal.mode.
ROUND_HALF_DOWN = 4
 

Indicates that digits >= 6 should be rounded up, others rounded down. See BigDecimal.mode.
ROUND_HALF_EVEN = 7
 

Round towards the even neighbor. See BigDecimal.mode.
ROUND_HALF_UP = 3
 

Indicates that digits >= 5 should be rounded up, others rounded down. See BigDecimal.mode.
ROUND_MODE = 0x100
 

Determines what happens when a result must be rounded in order to fit in the appropriate number of significant digits. See BigDecimal.mode.
ROUND_UP = 1
 

Indicates that values should be rounded away from zero. See BigDecimal.mode.
SIGN_NEGATIVE_FINITE = -2
 

Indicates that a value is negative and finite. See BigDecimal.sign.
SIGN_NEGATIVE_INFINITE = -3
 

Indicates that a value is negative and infinite. See BigDecimal.sign.
SIGN_NEGATIVE_ZERO = -1
 

Indicates that a value is -0. See BigDecimal.sign.
SIGN_NaN = 0
 

Indicates that a value is not a number. See BigDecimal.sign.
SIGN_POSITIVE_FINITE = 2
 

Indicates that a value is positive and finite. See BigDecimal.sign.
SIGN_POSITIVE_INFINITE = 3
 

Indicates that a value is positive and infinite. See BigDecimal.sign.
SIGN_POSITIVE_ZERO = 1
 

Indicates that a value is +0. See BigDecimal.sign.
VERSION = rb_str_new2(BIGDECIMAL_VERSION)
 

The version of bigdecimal library

Class Public methods

_load(p1)

Internal method used to provide marshalling support. See the Marshal module.

Source: show 

static VALUE
BigDecimal_load(VALUE self, VALUE str)
{
    ENTER(2);
    Real *pv;
    unsigned char *pch;
    unsigned char ch;
    unsigned long m=0;

    pch = (unsigned char *)StringValueCStr(str);
    /* First get max prec */
    while((*pch) != (unsigned char)'\0' && (ch = *pch++) != (unsigned char)':') {
        if(!ISDIGIT(ch)) {
            rb_raise(rb_eTypeError, "load failed: invalid character in the marshaled string");
        }
        m = m*10 + (unsigned long)(ch-'0');
    }
    if (m > VpBaseFig()) m -= VpBaseFig();
    GUARD_OBJ(pv, VpNewRbClass(m, (char *)pch, self, true, true));
    m /= VpBaseFig();
    if (m && pv->MaxPrec > m) {
        pv->MaxPrec = m+1;
    }
    return VpCheckGetValue(pv);
}

double_fig()

Source: show 

inline VALUE
BigDecimal_double_fig(VALUE self)
{
    return INT2FIX(VpDblFig());
}

interpret_loosely(p1)

Source: show 

static VALUE
BigDecimal_s_interpret_loosely(VALUE klass, VALUE str)
{
    char const *c_str = StringValueCStr(str);
    Real *vp = VpNewRbClass(0, c_str, klass, false, true);
    if (!vp)
        return Qnil;
    else
        return VpCheckGetValue(vp);
}

json_create(object)

See as_json.

Source: show | on GitHub 

# File ruby/ext/json/lib/json/add/bigdecimal.rb, line 13
def self.json_create(object)
  BigDecimal._load object['b']
end

BigDecimal.limit(digits)

Limit the number of significant digits in newly created BigDecimal numbers to the specified value. Rounding is performed as necessary, as specified by BigDecimal.mode.

A limit of 0, the default, means no upper limit.

The limit specified by this method takes less priority over any limit specified to instance methods such as ceil, floor, truncate, or round.

Source: show 

static VALUE
BigDecimal_limit(int argc, VALUE *argv, VALUE self)
{
    VALUE  nFig;
    VALUE  nCur = SIZET2NUM(VpGetPrecLimit());

    if (rb_scan_args(argc, argv, "01", &nFig) == 1) {
        int nf;
        if (NIL_P(nFig)) return nCur;
        nf = NUM2INT(nFig);
        if (nf < 0) {
            rb_raise(rb_eArgError, "argument must be positive");
        }
        VpSetPrecLimit(nf);
    }
    return nCur;
}

BigDecimal.mode(mode, setting = nil) → integer

Returns an integer representing the mode settings for exception handling and rounding.

These modes control exception handling:

  • BigDecimal::EXCEPTION_NaN.

  • BigDecimal::EXCEPTION_INFINITY.

  • BigDecimal::EXCEPTION_UNDERFLOW.

  • BigDecimal::EXCEPTION_OVERFLOW.

  • BigDecimal::EXCEPTION_ZERODIVIDE.

  • BigDecimal::EXCEPTION_ALL.

Values for setting for exception handling:

  • true: sets the given mode to true.

  • false: sets the given mode to false.

  • nil: does not modify the mode settings.

You can use method BigDecimal.save_exception_mode to temporarily change, and then automatically restore, exception modes.

For clarity, some examples below begin by setting all exception modes to false.

This mode controls the way rounding is to be performed:

  • BigDecimal::ROUND_MODE

You can use method BigDecimal.save_rounding_mode to temporarily change, and then automatically restore, the rounding mode.

NaNs

Mode BigDecimal::EXCEPTION_NaN controls behavior when a BigDecimal NaN is created.

Settings:

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal('NaN')                                 # => NaN
BigDecimal.mode(BigDecimal::EXCEPTION_NaN, true)  # => 2
BigDecimal('NaN') # Raises FloatDomainError

Infinities

Mode BigDecimal::EXCEPTION_INFINITY controls behavior when a BigDecimal Infinity or -Infinity is created. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)     # => 0
BigDecimal('Infinity')                                # => Infinity
BigDecimal('-Infinity')                               # => -Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_INFINITY, true) # => 1
BigDecimal('Infinity')  # Raises FloatDomainError
BigDecimal('-Infinity') # Raises FloatDomainError

Underflow

Mode BigDecimal::EXCEPTION_UNDERFLOW controls behavior when a BigDecimal underflow occurs. Settings:

  • false (default): Returns BigDecimal('0') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)      # => 0
def flow_under
  x = BigDecimal('0.1')
  100.times { x *= x }
end
flow_under                                             # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_UNDERFLOW, true) # => 4
flow_under # Raises FloatDomainError

Overflow

Mode BigDecimal::EXCEPTION_OVERFLOW controls behavior when a BigDecimal overflow occurs. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)     # => 0
def flow_over
  x = BigDecimal('10')
  100.times { x *= x }
end
flow_over                                             # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true) # => 1
flow_over # Raises FloatDomainError

Zero Division

Mode BigDecimal::EXCEPTION_ZERODIVIDE controls behavior when a zero-division occurs. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)       # => 0
one = BigDecimal('1')
zero = BigDecimal('0')
one / zero                                              # => Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_ZERODIVIDE, true) # => 16
one / zero # Raises FloatDomainError

All Exceptions

Mode BigDecimal::EXCEPTION_ALL controls all of the above:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, true)  # => 23

Rounding

Mode BigDecimal::ROUND_MODE controls the way rounding is to be performed; its setting values are:

  • ROUND_UP: Round away from zero. Aliased as :up.

  • ROUND_DOWN: Round toward zero. Aliased as :down and :truncate.

  • ROUND_HALF_UP: Round toward the nearest neighbor; if the neighbors are equidistant, round away from zero. Aliased as :half_up and :default.

  • ROUND_HALF_DOWN: Round toward the nearest neighbor; if the neighbors are equidistant, round toward zero. Aliased as :half_down.

  • ROUND_HALF_EVEN (Banker’s rounding): Round toward the nearest neighbor; if the neighbors are equidistant, round toward the even neighbor. Aliased as :half_even and :banker.

  • ROUND_CEILING: Round toward positive infinity. Aliased as :ceiling and :ceil.

  • ROUND_FLOOR: Round toward negative infinity. Aliased as :floor:.

Source: show 

static VALUE
BigDecimal_mode(int argc, VALUE *argv, VALUE self)
{
    VALUE which;
    VALUE val;
    unsigned long f,fo;

    rb_scan_args(argc, argv, "11", &which, &val);
    f = (unsigned long)NUM2INT(which);

    if (f & VP_EXCEPTION_ALL) {
        /* Exception mode setting */
        fo = VpGetException();
        if (val == Qnil) return INT2FIX(fo);
        if (val != Qfalse && val!=Qtrue) {
            rb_raise(rb_eArgError, "second argument must be true or false");
            return Qnil; /* Not reached */
        }
        if (f & VP_EXCEPTION_INFINITY) {
            VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_INFINITY) :
                        (fo & (~VP_EXCEPTION_INFINITY))));
        }
        fo = VpGetException();
        if (f & VP_EXCEPTION_NaN) {
            VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_NaN) :
                        (fo & (~VP_EXCEPTION_NaN))));
        }
        fo = VpGetException();
        if (f & VP_EXCEPTION_UNDERFLOW) {
            VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_UNDERFLOW) :
                        (fo & (~VP_EXCEPTION_UNDERFLOW))));
        }
        fo = VpGetException();
        if(f & VP_EXCEPTION_ZERODIVIDE) {
            VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_ZERODIVIDE) :
                        (fo & (~VP_EXCEPTION_ZERODIVIDE))));
        }
        fo = VpGetException();
        return INT2FIX(fo);
    }
    if (VP_ROUND_MODE == f) {
        /* Rounding mode setting */
        unsigned short sw;
        fo = VpGetRoundMode();
        if (NIL_P(val)) return INT2FIX(fo);
        sw = check_rounding_mode(val);
        fo = VpSetRoundMode(sw);
        return INT2FIX(fo);
    }
    rb_raise(rb_eTypeError, "first argument for BigDecimal.mode invalid");
    return Qnil;
}

BigDecimal.save_exception_mode { ... }

Execute the provided block, but preserve the exception mode

BigDecimal.save_exception_mode do
  BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
  BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)

  BigDecimal(BigDecimal('Infinity'))
  BigDecimal(BigDecimal('-Infinity'))
  BigDecimal(BigDecimal('NaN'))
end

For use with the BigDecimal::EXCEPTION_*

See BigDecimal.mode

Source: show 

static VALUE
BigDecimal_save_exception_mode(VALUE self)
{
    unsigned short const exception_mode = VpGetException();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetException(exception_mode);
    if (state) rb_jump_tag(state);
    return ret;
}

BigDecimal.save_limit { ... }

Execute the provided block, but preserve the precision limit

BigDecimal.limit(100)
puts BigDecimal.limit
BigDecimal.save_limit do
    BigDecimal.limit(200)
    puts BigDecimal.limit
end
puts BigDecimal.limit

Source: show 

static VALUE
BigDecimal_save_limit(VALUE self)
{
    size_t const limit = VpGetPrecLimit();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetPrecLimit(limit);
    if (state) rb_jump_tag(state);
    return ret;
}

BigDecimal.save_rounding_mode { ... }

Execute the provided block, but preserve the rounding mode

BigDecimal.save_rounding_mode do
  BigDecimal.mode(BigDecimal::ROUND_MODE, :up)
  puts BigDecimal.mode(BigDecimal::ROUND_MODE)
end

For use with the BigDecimal::ROUND_*

See BigDecimal.mode

Source: show 

static VALUE
BigDecimal_save_rounding_mode(VALUE self)
{
    unsigned short const round_mode = VpGetRoundMode();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetRoundMode(round_mode);
    if (state) rb_jump_tag(state);
    return ret;
}

Instance Public methods

a % b

Returns the modulus from dividing by b.

See BigDecimal#divmod.

Also aliased as: modulo

Source: show 

static VALUE
BigDecimal_mod(VALUE self, VALUE r)

*(p1)

Source: show 

static VALUE
BigDecimal_mult(VALUE self, VALUE r)
{
    ENTER(5);
    Real *c, *a, *b;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    if (RB_TYPE_P(r, T_FLOAT)) {
        b = GetVpValueWithPrec(r, 0, 1);
    }
    else if (RB_TYPE_P(r, T_RATIONAL)) {
        b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1);
    }
    else {
        b = GetVpValue(r,0);
    }

    if (!b) return DoSomeOne(self, r, '*');
    SAVE(b);

    mx = a->Prec + b->Prec;
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx * (VpBaseFig() + 1)));
    VpMult(c, a, b);
    return VpCheckGetValue(c);
}

self ** other → bigdecimal

Returns the BigDecimal value of self raised to power other:

b = BigDecimal('3.14')
b ** 2              # => 0.98596e1
b ** 2.0            # => 0.98596e1
b ** Rational(2, 1) # => 0.98596e1

Related: BigDecimal#power.

Source: show 

static VALUE
BigDecimal_power_op(VALUE self, VALUE exp)
{
    return BigDecimal_power(1, &exp, self);
}

self + value → bigdecimal

Returns the BigDecimal sum of self and value:

b = BigDecimal('111111.111') # => 0.111111111e6
b + 2                        # => 0.111113111e6
b + 2.0                      # => 0.111113111e6
b + Rational(2, 1)           # => 0.111113111e6
b + Complex(2, 0)            # => (0.111113111e6+0i)

See the Note About Precision.

Source: show 

static VALUE
BigDecimal_add(VALUE self, VALUE r)
{
    ENTER(5);
    Real *c, *a, *b;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    if (RB_TYPE_P(r, T_FLOAT)) {
        b = GetVpValueWithPrec(r, 0, 1);
    }
    else if (RB_TYPE_P(r, T_RATIONAL)) {
        b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1);
    }
    else {
        b = GetVpValue(r, 0);
    }

    if (!b) return DoSomeOne(self,r,'+');
    SAVE(b);

    if (VpIsNaN(b)) return b->obj;
    if (VpIsNaN(a)) return a->obj;

    mx = GetAddSubPrec(a, b);
    if (mx == (size_t)-1L) {
        GUARD_OBJ(c, NewZeroWrapLimited(1, VpBaseFig() + 1));
        VpAddSub(c, a, b, 1);
    }
    else {
        GUARD_OBJ(c, NewZeroWrapLimited(1, mx * (VpBaseFig() + 1)));
        if (!mx) {
            VpSetInf(c, VpGetSign(a));
        }
        else {
            VpAddSub(c, a, b, 1);
        }
    }
    return VpCheckGetValue(c);
}

+big_decimal → self

Returns self:

+BigDecimal(5)  # => 0.5e1
+BigDecimal(-5) # => -0.5e1

Source: show 

static VALUE
BigDecimal_uplus(VALUE self)
{
    return self;
}

self - value → bigdecimal

Returns the BigDecimal difference of self and value:

b = BigDecimal('333333.333') # => 0.333333333e6
b - 2                        # => 0.333331333e6
b - 2.0                      # => 0.333331333e6
b - Rational(2, 1)           # => 0.333331333e6
b - Complex(2, 0)            # => (0.333331333e6+0i)

See the Note About Precision.

Source: show 

static VALUE
BigDecimal_sub(VALUE self, VALUE r)
{
    ENTER(5);
    Real *c, *a, *b;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self,1));
    if (RB_TYPE_P(r, T_FLOAT)) {
        b = GetVpValueWithPrec(r, 0, 1);
    }
    else if (RB_TYPE_P(r, T_RATIONAL)) {
        b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1);
    }
    else {
        b = GetVpValue(r,0);
    }

    if (!b) return DoSomeOne(self,r,'-');
    SAVE(b);

    if (VpIsNaN(b)) return b->obj;
    if (VpIsNaN(a)) return a->obj;

    mx = GetAddSubPrec(a,b);
    if (mx == (size_t)-1L) {
        GUARD_OBJ(c, NewZeroWrapLimited(1, VpBaseFig() + 1));
        VpAddSub(c, a, b, -1);
    }
    else {
        GUARD_OBJ(c, NewZeroWrapLimited(1, mx *(VpBaseFig() + 1)));
        if (!mx) {
            VpSetInf(c,VpGetSign(a));
        }
        else {
            VpAddSub(c, a, b, -1);
        }
    }
    return VpCheckGetValue(c);
}

-self → bigdecimal

Returns the BigDecimal negation of self:

b0 = BigDecimal('1.5')
b1 = -b0 # => -0.15e1
b2 = -b1 # => 0.15e1

Source: show 

static VALUE
BigDecimal_neg(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    GUARD_OBJ(a, GetVpValue(self, 1));
    GUARD_OBJ(c, NewZeroWrapLimited(1, a->Prec *(VpBaseFig() + 1)));
    VpAsgn(c, a, -1);
    return VpCheckGetValue(c);
}

a / b → bigdecimal

Divide by the specified value.

The result precision will be the precision of the larger operand, but its minimum is 2*Float::DIG.

See BigDecimal#div. See BigDecimal#quo.

Source: show 

static VALUE
BigDecimal_div(VALUE self, VALUE r)
/* For c = self/r: with round operation */
{
    ENTER(5);
    Real *c=NULL, *res=NULL, *div = NULL;
    r = BigDecimal_divide(self, r, &c, &res, &div);
    if (!NIL_P(r)) return r; /* coerced by other */
    SAVE(c); SAVE(res); SAVE(div);
    /* a/b = c + r/b */
    /* c xxxxx
       r 00000yyyyy  ==> (y/b)*BASE >= HALF_BASE
     */
    /* Round */
    if (VpHasVal(div)) { /* frac[0] must be zero for NaN,INF,Zero */
        VpInternalRound(c, 0, c->frac[c->Prec-1], (DECDIG)(VpBaseVal() * (DECDIG_DBL)res->frac[0] / div->frac[0]));
    }
    return VpCheckGetValue(c);
}

self < other → true or false

Returns true if self is less than other, false otherwise:

b = BigDecimal('1.5') # => 0.15e1
b < 2                 # => true
b < 2.0               # => true
b < Rational(2, 1)    # => true
b < 1.5               # => false

Raises an exception if the comparison cannot be made.

Source: show 

static VALUE
BigDecimal_lt(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '<');
}

self <= other → true or false

Returns true if self is less or equal to than other, false otherwise:

b = BigDecimal('1.5') # => 0.15e1
b <= 2                # => true
b <= 2.0              # => true
b <= Rational(2, 1)   # => true
b <= 1.5              # => true
b < 1                 # => false

Raises an exception if the comparison cannot be made.

Source: show 

static VALUE
BigDecimal_le(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, 'L');
}

<=>(p1)

The comparison operator. a <=> b is 0 if a == b, 1 if a > b, -1 if a < b.

Source: show 

static VALUE
BigDecimal_comp(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '*');
}

==(p1)

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true
Also aliased as: ===, eql?

Source: show 

static VALUE
BigDecimal_eq(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '=');
}

===(p1)

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true
Alias for: ==

self > other → true or false

Returns true if self is greater than other, false otherwise:

b = BigDecimal('1.5')
b > 1              # => true
b > 1.0            # => true
b > Rational(1, 1) # => true
b > 2              # => false

Raises an exception if the comparison cannot be made.

Source: show 

static VALUE
BigDecimal_gt(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '>');
}

self >= other → true or false

Returns true if self is greater than or equal to other, false otherwise:

b = BigDecimal('1.5')
b >= 1              # => true
b >= 1.0            # => true
b >= Rational(1, 1) # => true
b >= 1.5            # => true
b > 2               # => false

Raises an exception if the comparison cannot be made.

Source: show 

static VALUE
BigDecimal_ge(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, 'G');
}

_dump → string

Returns a string representing the marshalling of self. See module Marshal.

inf = BigDecimal('Infinity') # => Infinity
dumped = inf._dump           # => "9:Infinity"
BigDecimal._load(dumped)     # => Infinity

Source: show 

static VALUE
BigDecimal_dump(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real *vp;
    char *psz;
    VALUE dummy;
    volatile VALUE dump;
    size_t len;

    rb_scan_args(argc, argv, "01", &dummy);
    GUARD_OBJ(vp,GetVpValue(self, 1));
    dump = rb_str_new(0, VpNumOfChars(vp, "E")+50);
    psz = RSTRING_PTR(dump);
    snprintf(psz, RSTRING_LEN(dump), "%"PRIuSIZE":", VpMaxPrec(vp)*VpBaseFig());
    len = strlen(psz);
    VpToString(vp, psz+len, RSTRING_LEN(dump)-len, 0, 0);
    rb_str_resize(dump, strlen(psz));
    return dump;
}

abs → bigdecimal

Returns the BigDecimal absolute value of self:

BigDecimal('5').abs  # => 0.5e1
BigDecimal('-3').abs # => 0.3e1

Source: show 

static VALUE
BigDecimal_abs(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpAsgn(c, a, 1);
    VpChangeSign(c, 1);
    return VpCheckGetValue(c);
}

add(value, ndigits) → new_bigdecimal

Returns the BigDecimal sum of self and value with a precision of ndigits decimal digits.

When ndigits is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see BigDecimal.mode.

Examples:

# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('111111.111')
b.add(1, 0)               # => 0.111112111e6
b.add(1, 3)               # => 0.111e6
b.add(1, 6)               # => 0.111112e6
b.add(1, 15)              # => 0.111112111e6
b.add(1.0, 15)            # => 0.111112111e6
b.add(Rational(1, 1), 15) # => 0.111112111e6

Source: show 

static VALUE
BigDecimal_add2(VALUE self, VALUE b, VALUE n)
{
    ENTER(2);
    Real *cv;
    SIGNED_VALUE mx = check_int_precision(n);
    if (mx == 0) return BigDecimal_add(self, b);
    else {
        size_t pl = VpSetPrecLimit(0);
        VALUE   c = BigDecimal_add(self, b);
        VpSetPrecLimit(pl);
        GUARD_OBJ(cv, GetVpValue(c, 1));
        VpLeftRound(cv, VpGetRoundMode(), mx);
        return VpCheckGetValue(cv);
    }
}

as_json(*)

Methods BigDecimal#as_json and BigDecimal.json_create may be used to serialize and deserialize a BigDecimal object; see Marshal.

Method BigDecimal#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/bigdecimal'
x = BigDecimal(2).as_json             # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"}
y = BigDecimal(2.0, 4).as_json        # => {"json_class"=>"BigDecimal", "b"=>"36:0.2e1"}
z = BigDecimal(Complex(2, 0)).as_json # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"}

Method JSON.create deserializes such a hash, returning a BigDecimal object:

BigDecimal.json_create(x) # => 0.2e1
BigDecimal.json_create(y) # => 0.2e1
BigDecimal.json_create(z) # => 0.2e1

Source: show | on GitHub 

# File ruby/ext/json/lib/json/add/bigdecimal.rb, line 35
def as_json(*)
  {
    JSON.create_id => self.class.name,
    'b'            => _dump,
  }
end

ceil(n)

Return the smallest integer greater than or equal to the value, as a BigDecimal.

BigDecimal('3.14159').ceil #=> 4
BigDecimal('-9.1').ceil #=> -9

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal('3.14159').ceil(3) #=> 3.142
BigDecimal('13345.234').ceil(-2) #=> 13400.0

Source: show 

static VALUE
BigDecimal_ceil(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real *c, *a;
    int iLoc;
    VALUE vLoc;
    size_t mx, pl = VpSetPrecLimit(0);

    if (rb_scan_args(argc, argv, "01", &vLoc) == 0) {
        iLoc = 0;
    } else {
        iLoc = NUM2INT(vLoc);
    }

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpSetPrecLimit(pl);
    VpActiveRound(c, a, VP_ROUND_CEIL, iLoc);
    if (argc == 0) {
        return BigDecimal_to_i(VpCheckGetValue(c));
    }
    return VpCheckGetValue(c);
}

clone()

Also aliased as: dup

Source: show 

static VALUE
BigDecimal_clone(VALUE self)
{
  return self;
}

coerce(p1)

The coerce method provides support for Ruby type coercion. It is not enabled by default.

This means that binary operations like + * / or - can often be performed on a BigDecimal and an object of another type, if the other object can be coerced into a BigDecimal value.

e.g.

a = BigDecimal("1.0")
b = a / 2.0 #=> 0.5

Note that coercing a String to a BigDecimal is not supported by default; it requires a special compile-time option when building Ruby.

Source: show 

static VALUE
BigDecimal_coerce(VALUE self, VALUE other)
{
    ENTER(2);
    VALUE obj;
    Real *b;

    if (RB_TYPE_P(other, T_FLOAT)) {
        GUARD_OBJ(b, GetVpValueWithPrec(other, 0, 1));
        obj = rb_assoc_new(VpCheckGetValue(b), self);
    }
    else {
        if (RB_TYPE_P(other, T_RATIONAL)) {
            Real* pv = DATA_PTR(self);
            GUARD_OBJ(b, GetVpValueWithPrec(other, pv->Prec*VpBaseFig(), 1));
        }
        else {
            GUARD_OBJ(b, GetVpValue(other, 1));
        }
        obj = rb_assoc_new(b->obj, self);
    }

    return obj;
}

div(value) → integer
div(value, digits) → bigdecimal or integer

Divide by the specified value.

digits

If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.

If digits is 0, the result is the same as for the / operator or quo.

If digits is not specified, the result is an integer, by analogy with Float#div; see also BigDecimal#divmod.

See BigDecimal#/. See BigDecimal#quo.

Examples:

a = BigDecimal("4")
b = BigDecimal("3")

a.div(b, 3)  # => 0.133e1

a.div(b, 0)  # => 0.1333333333333333333e1
a / b        # => 0.1333333333333333333e1
a.quo(b)     # => 0.1333333333333333333e1

a.div(b)     # => 1

Source: show 

static VALUE
BigDecimal_div3(int argc, VALUE *argv, VALUE self)
{
    VALUE b,n;

    rb_scan_args(argc, argv, "11", &b, &n);

    return BigDecimal_div2(self, b, n);
}

divmod(value)

Divides by the specified value, and returns the quotient and modulus as BigDecimal numbers. The quotient is rounded towards negative infinity.

For example:

require 'bigdecimal'

a = BigDecimal("42")
b = BigDecimal("9")

q, m = a.divmod(b)

c = q * b + m

a == c  #=> true

The quotient q is (a/b).floor, and the modulus is the amount that must be added to q * b to get a.

Source: show 

static VALUE
BigDecimal_divmod(VALUE self, VALUE r)
{
    ENTER(5);
    Real *div = NULL, *mod = NULL;

    if (BigDecimal_DoDivmod(self, r, &div, &mod)) {
        SAVE(div); SAVE(mod);
        return rb_assoc_new(VpCheckGetValue(div), VpCheckGetValue(mod));
    }
    return DoSomeOne(self,r,rb_intern("divmod"));
}

dup()

Alias for: clone

eql?(p1)

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true
Alias for: ==

exponent()

Returns the exponent of the BigDecimal number, as an Integer.

If the number can be represented as 0.xxxxxx*10**n where xxxxxx is a string of digits with no leading zeros, then n is the exponent.

Source: show 

static VALUE
BigDecimal_exponent(VALUE self)
{
    ssize_t e = VpExponent10(GetVpValue(self, 1));
    return SSIZET2NUM(e);
}

finite?()

Returns True if the value is finite (not NaN or infinite).

Source: show 

static VALUE
BigDecimal_IsFinite(VALUE self)
{
    Real *p = GetVpValue(self, 1);
    if (VpIsNaN(p)) return Qfalse;
    if (VpIsInf(p)) return Qfalse;
    return Qtrue;
}

fix()

Return the integer part of the number, as a BigDecimal.

Source: show 

static VALUE
BigDecimal_fix(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpActiveRound(c, a, VP_ROUND_DOWN, 0); /* 0: round off */
    return VpCheckGetValue(c);
}

floor(n)

Return the largest integer less than or equal to the value, as a BigDecimal.

BigDecimal('3.14159').floor #=> 3
BigDecimal('-9.1').floor #=> -10

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal('3.14159').floor(3) #=> 3.141
BigDecimal('13345.234').floor(-2) #=> 13300.0

Source: show 

static VALUE
BigDecimal_floor(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real *c, *a;
    int iLoc;
    VALUE vLoc;
    size_t mx, pl = VpSetPrecLimit(0);

    if (rb_scan_args(argc, argv, "01", &vLoc)==0) {
        iLoc = 0;
    }
    else {
        iLoc = NUM2INT(vLoc);
    }

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpSetPrecLimit(pl);
    VpActiveRound(c, a, VP_ROUND_FLOOR, iLoc);
#ifdef BIGDECIMAL_DEBUG
    VPrint(stderr, "floor: c=%\n", c);
#endif
    if (argc == 0) {
        return BigDecimal_to_i(VpCheckGetValue(c));
    }
    return VpCheckGetValue(c);
}

frac()

Return the fractional part of the number, as a BigDecimal.

Source: show 

static VALUE
BigDecimal_frac(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    size_t mx;

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpFrac(c, a);
    return VpCheckGetValue(c);
}

hash → integer

Returns the integer hash value for self.

Two instances of BigDecimal have the same hash value if and only if they have equal:

  • Sign.

  • Fractional part.

  • Exponent.

Source: show 

static VALUE
BigDecimal_hash(VALUE self)
{
    ENTER(1);
    Real *p;
    st_index_t hash;

    GUARD_OBJ(p, GetVpValue(self, 1));
    hash = (st_index_t)p->sign;
    /* hash!=2: the case for 0(1),NaN(0) or +-Infinity(3) is sign itself */
    if(hash == 2 || hash == (st_index_t)-2) {
        hash ^= rb_memhash(p->frac, sizeof(DECDIG)*p->Prec);
        hash += p->exponent;
    }
    return ST2FIX(hash);
}

infinite?()

Returns nil, -1, or +1 depending on whether the value is finite, -Infinity, or +Infinity.

Source: show 

static VALUE
BigDecimal_IsInfinite(VALUE self)
{
    Real *p = GetVpValue(self, 1);
    if (VpIsPosInf(p)) return INT2FIX(1);
    if (VpIsNegInf(p)) return INT2FIX(-1);
    return Qnil;
}

inspect()

Returns a string representation of self.

BigDecimal("1234.5678").inspect
  #=> "0.12345678e4"

Source: show 

static VALUE
BigDecimal_inspect(VALUE self)
{
    ENTER(5);
    Real *vp;
    volatile VALUE str;
    size_t nc;

    GUARD_OBJ(vp, GetVpValue(self, 1));
    nc = VpNumOfChars(vp, "E");

    str = rb_str_new(0, nc);
    VpToString(vp, RSTRING_PTR(str), RSTRING_LEN(str), 0, 0);
    rb_str_resize(str, strlen(RSTRING_PTR(str)));
    return str;
}

a.modulo(b)

Returns the modulus from dividing by b.

See BigDecimal#divmod.

Alias for: %

mult(other, ndigits) → bigdecimal

Returns the BigDecimal product of self and value with a precision of ndigits decimal digits.

When ndigits is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see BigDecimal.mode.

Examples:

# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('555555.555')
b.mult(3, 0)              # => 0.1666666665e7
b.mult(3, 3)              # => 0.167e7
b.mult(3, 6)              # => 0.166667e7
b.mult(3, 15)             # => 0.1666666665e7
b.mult(3.0, 0)            # => 0.1666666665e7
b.mult(Rational(3, 1), 0) # => 0.1666666665e7
b.mult(Complex(3, 0), 0)  # => (0.1666666665e7+0.0i)

Source: show 

static VALUE
BigDecimal_mult2(VALUE self, VALUE b, VALUE n)
{
    ENTER(2);
    Real *cv;
    SIGNED_VALUE mx = check_int_precision(n);
    if (mx == 0) return BigDecimal_mult(self, b);
    else {
        size_t pl = VpSetPrecLimit(0);
        VALUE   c = BigDecimal_mult(self, b);
        VpSetPrecLimit(pl);
        GUARD_OBJ(cv, GetVpValue(c, 1));
        VpLeftRound(cv, VpGetRoundMode(), mx);
        return VpCheckGetValue(cv);
    }
}

n_significant_digits → integer

Returns the number of decimal significant digits in self.

BigDecimal("0").n_significant_digits         # => 0
BigDecimal("1").n_significant_digits         # => 1
BigDecimal("1.1").n_significant_digits       # => 2
BigDecimal("3.1415").n_significant_digits    # => 5
BigDecimal("-1e20").n_significant_digits     # => 1
BigDecimal("1e-20").n_significant_digits     # => 1
BigDecimal("Infinity").n_significant_digits  # => 0
BigDecimal("-Infinity").n_significant_digits # => 0
BigDecimal("NaN").n_significant_digits       # => 0

Source: show 

static VALUE
BigDecimal_n_significant_digits(VALUE self)
{
    ENTER(1);

    Real *p;
    GUARD_OBJ(p, GetVpValue(self, 1));
    if (VpIsZero(p) || !VpIsDef(p)) {
        return INT2FIX(0);
    }

    ssize_t n = p->Prec;  /* The length of frac without trailing zeros. */
    for (n = p->Prec; n > 0 && p->frac[n-1] == 0; --n);
    if (n == 0) return INT2FIX(0);

    DECDIG x;
    int nlz = BASE_FIG;
    for (x = p->frac[0]; x > 0; x /= 10) --nlz;

    int ntz = 0;
    for (x = p->frac[n-1]; x > 0 && x % 10 == 0; x /= 10) ++ntz;

    ssize_t n_significant_digits = BASE_FIG*n - nlz - ntz;
    return SSIZET2NUM(n_significant_digits);
}

nan?()

Returns True if the value is Not a Number.

Source: show 

static VALUE
BigDecimal_IsNaN(VALUE self)
{
    Real *p = GetVpValue(self, 1);
    if (VpIsNaN(p))  return Qtrue;
    return Qfalse;
}

nonzero?()

Returns self if the value is non-zero, nil otherwise.

Source: show 

static VALUE
BigDecimal_nonzero(VALUE self)
{
    Real *a = GetVpValue(self, 1);
    return VpIsZero(a) ? Qnil : self;
}

power(n)
power(n, prec)

Returns the value raised to the power of n.

Note that n must be an Integer.

Also available as the operator **.

Source: show 

static VALUE
BigDecimal_power(int argc, VALUE*argv, VALUE self)
{
    ENTER(5);
    VALUE vexp, prec;
    Real* exp = NULL;
    Real *x, *y;
    ssize_t mp, ma, n;
    SIGNED_VALUE int_exp;
    double d;

    rb_scan_args(argc, argv, "11", &vexp, &prec);

    GUARD_OBJ(x, GetVpValue(self, 1));
    n = NIL_P(prec) ? (ssize_t)(x->Prec*VpBaseFig()) : NUM2SSIZET(prec);

    if (VpIsNaN(x)) {
        y = NewZeroWrapLimited(1, n);
        VpSetNaN(y);
        RB_GC_GUARD(y->obj);
        return VpCheckGetValue(y);
    }

  retry:
    switch (TYPE(vexp)) {
      case T_FIXNUM:
        break;

      case T_BIGNUM:
        break;

      case T_FLOAT:
        d = RFLOAT_VALUE(vexp);
        if (d == round(d)) {
            if (FIXABLE(d)) {
                vexp = LONG2FIX((long)d);
            }
            else {
                vexp = rb_dbl2big(d);
            }
            goto retry;
        }
        if (NIL_P(prec)) {
            n += BIGDECIMAL_DOUBLE_FIGURES;
        }
        exp = GetVpValueWithPrec(vexp, 0, 1);
        break;

      case T_RATIONAL:
        if (is_zero(rb_rational_num(vexp))) {
            if (is_positive(vexp)) {
                vexp = INT2FIX(0);
                goto retry;
            }
        }
        else if (is_one(rb_rational_den(vexp))) {
            vexp = rb_rational_num(vexp);
            goto retry;
        }
        exp = GetVpValueWithPrec(vexp, n, 1);
        if (NIL_P(prec)) {
            n += n;
        }
        break;

      case T_DATA:
        if (is_kind_of_BigDecimal(vexp)) {
            VALUE zero = INT2FIX(0);
            VALUE rounded = BigDecimal_round(1, &zero, vexp);
            if (RTEST(BigDecimal_eq(vexp, rounded))) {
                vexp = BigDecimal_to_i(vexp);
                goto retry;
            }
            if (NIL_P(prec)) {
                GUARD_OBJ(y, GetVpValue(vexp, 1));
                n += y->Prec*VpBaseFig();
            }
            exp = DATA_PTR(vexp);
            break;
        }
        /* fall through */
      default:
        rb_raise(rb_eTypeError,
                 "wrong argument type %"PRIsVALUE" (expected scalar Numeric)",
                 RB_OBJ_CLASSNAME(vexp));
    }

    if (VpIsZero(x)) {
        if (is_negative(vexp)) {
            y = NewZeroWrapNolimit(1, n);
            if (BIGDECIMAL_NEGATIVE_P(x)) {
                if (is_integer(vexp)) {
                    if (is_even(vexp)) {
                        /* (-0) ** (-even_integer)  -> Infinity */
                        VpSetPosInf(y);
                    }
                    else {
                        /* (-0) ** (-odd_integer)  -> -Infinity */
                        VpSetNegInf(y);
                    }
                }
                else {
                    /* (-0) ** (-non_integer)  -> Infinity */
                    VpSetPosInf(y);
                }
            }
            else {
                /* (+0) ** (-num)  -> Infinity */
                VpSetPosInf(y);
            }
            RB_GC_GUARD(y->obj);
            return VpCheckGetValue(y);
        }
        else if (is_zero(vexp)) {
            return VpCheckGetValue(NewOneWrapLimited(1, n));
        }
        else {
            return VpCheckGetValue(NewZeroWrapLimited(1, n));
        }
    }

    if (is_zero(vexp)) {
        return VpCheckGetValue(NewOneWrapLimited(1, n));
    }
    else if (is_one(vexp)) {
        return self;
    }

    if (VpIsInf(x)) {
        if (is_negative(vexp)) {
            if (BIGDECIMAL_NEGATIVE_P(x)) {
                if (is_integer(vexp)) {
                    if (is_even(vexp)) {
                        /* (-Infinity) ** (-even_integer) -> +0 */
                        return VpCheckGetValue(NewZeroWrapLimited(1, n));
                    }
                    else {
                        /* (-Infinity) ** (-odd_integer) -> -0 */
                        return VpCheckGetValue(NewZeroWrapLimited(-1, n));
                    }
                }
                else {
                    /* (-Infinity) ** (-non_integer) -> -0 */
                    return VpCheckGetValue(NewZeroWrapLimited(-1, n));
                }
            }
            else {
                return VpCheckGetValue(NewZeroWrapLimited(1, n));
            }
        }
        else {
            y = NewZeroWrapLimited(1, n);
            if (BIGDECIMAL_NEGATIVE_P(x)) {
                if (is_integer(vexp)) {
                    if (is_even(vexp)) {
                        VpSetPosInf(y);
                    }
                    else {
                        VpSetNegInf(y);
                    }
                }
                else {
                    /* TODO: support complex */
                    rb_raise(rb_eMathDomainError,
                            "a non-integral exponent for a negative base");
                }
            }
            else {
                VpSetPosInf(y);
            }
            return VpCheckGetValue(y);
        }
    }

    if (exp != NULL) {
        return bigdecimal_power_by_bigdecimal(x, exp, n);
    }
    else if (RB_TYPE_P(vexp, T_BIGNUM)) {
        VALUE abs_value = BigDecimal_abs(self);
        if (is_one(abs_value)) {
            return VpCheckGetValue(NewOneWrapLimited(1, n));
        }
        else if (RTEST(rb_funcall(abs_value, '<', 1, INT2FIX(1)))) {
            if (is_negative(vexp)) {
                y = NewZeroWrapLimited(1, n);
                VpSetInf(y, (is_even(vexp) ? 1 : -1) * VpGetSign(x));
                return VpCheckGetValue(y);
            }
            else if (BIGDECIMAL_NEGATIVE_P(x) && is_even(vexp)) {
                return VpCheckGetValue(NewZeroWrapLimited(-1, n));
            }
            else {
                return VpCheckGetValue(NewZeroWrapLimited(1, n));
            }
        }
        else {
            if (is_positive(vexp)) {
                y = NewZeroWrapLimited(1, n);
                VpSetInf(y, (is_even(vexp) ? 1 : -1) * VpGetSign(x));
                return VpCheckGetValue(y);
            }
            else if (BIGDECIMAL_NEGATIVE_P(x) && is_even(vexp)) {
                return VpCheckGetValue(NewZeroWrapLimited(-1, n));
            }
            else {
                return VpCheckGetValue(NewZeroWrapLimited(1, n));
            }
        }
    }

    int_exp = FIX2LONG(vexp);
    ma = int_exp;
    if (ma <  0) ma = -ma;
    if (ma == 0) ma = 1;

    if (VpIsDef(x)) {
        mp = x->Prec * (VpBaseFig() + 1);
        GUARD_OBJ(y, NewZeroWrapLimited(1, mp * (ma + 1)));
    }
    else {
        GUARD_OBJ(y, NewZeroWrapLimited(1, 1));
    }
    VpPowerByInt(y, x, int_exp);
    if (!NIL_P(prec) && VpIsDef(y)) {
        VpMidRound(y, VpGetRoundMode(), n);
    }
    return VpCheckGetValue(y);
}

precision → integer

Returns the number of decimal digits in self:

BigDecimal("0").precision         # => 0
BigDecimal("1").precision         # => 1
BigDecimal("1.1").precision       # => 2
BigDecimal("3.1415").precision    # => 5
BigDecimal("-1e20").precision     # => 21
BigDecimal("1e-20").precision     # => 20
BigDecimal("Infinity").precision  # => 0
BigDecimal("-Infinity").precision # => 0
BigDecimal("NaN").precision       # => 0

Source: show 

static VALUE
BigDecimal_precision(VALUE self)
{
    ssize_t precision;
    BigDecimal_count_precision_and_scale(self, &precision, NULL);
    return SSIZET2NUM(precision);
}

precision_scale → [integer, integer]

Returns a 2-length array; the first item is the result of BigDecimal#precision and the second one is of BigDecimal#scale.

See BigDecimal#precision. See BigDecimal#scale.

Source: show 

static VALUE
BigDecimal_precision_scale(VALUE self)
{
    ssize_t precision, scale;
    BigDecimal_count_precision_and_scale(self, &precision, &scale);
    return rb_assoc_new(SSIZET2NUM(precision), SSIZET2NUM(scale));
}

precs → array

Returns an Array of two Integer values that represent platform-dependent internal storage properties.

This method is deprecated and will be removed in the future. Instead, use BigDecimal#n_significant_digits for obtaining the number of significant digits in scientific notation, and BigDecimal#precision for obtaining the number of digits in decimal notation.

Source: show 

static VALUE
BigDecimal_prec(VALUE self)
{
    ENTER(1);
    Real *p;
    VALUE obj;

    rb_category_warn(RB_WARN_CATEGORY_DEPRECATED,
                     "BigDecimal#precs is deprecated and will be removed in the future; "
                     "use BigDecimal#precision instead.");

    GUARD_OBJ(p, GetVpValue(self, 1));
    obj = rb_assoc_new(SIZET2NUM(p->Prec*VpBaseFig()),
                       SIZET2NUM(p->MaxPrec*VpBaseFig()));
    return obj;
}

quo(value) → bigdecimal
quo(value, digits) → bigdecimal

Divide by the specified value.

digits

If specified and less than the number of significant digits of the result, the result is rounded to the given number of digits, according to the rounding mode indicated by BigDecimal.mode.

If digits is 0 or omitted, the result is the same as for the / operator.

See BigDecimal#/. See BigDecimal#div.

Source: show 

static VALUE
BigDecimal_quo(int argc, VALUE *argv, VALUE self)
{
    VALUE value, digits, result;
    SIGNED_VALUE n = -1;

    argc = rb_scan_args(argc, argv, "11", &value, &digits);
    if (argc > 1) {
        n = check_int_precision(digits);
    }

    if (n > 0) {
        result = BigDecimal_div2(self, value, digits);
    }
    else {
        result = BigDecimal_div(self, value);
    }

    return result;
}

remainder(value)

Returns the remainder from dividing by the value.

x.remainder(y) means x-y*(x/y).truncate

Source: show 

static VALUE
BigDecimal_remainder(VALUE self, VALUE r) /* remainder */
{
    VALUE  f;
    Real  *d, *rv = 0;
    f = BigDecimal_divremain(self, r, &d, &rv);
    if (!NIL_P(f)) return f;
    return VpCheckGetValue(rv);
}

round(n, mode)

Round to the nearest integer (by default), returning the result as a BigDecimal if n is specified, or as an Integer if it isn’t.

BigDecimal('3.14159').round #=> 3
BigDecimal('8.7').round #=> 9
BigDecimal('-9.9').round #=> -10

BigDecimal('3.14159').round(2).class.name #=> "BigDecimal"
BigDecimal('3.14159').round.class.name #=> "Integer"

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result, and return value will be an Integer.

BigDecimal('3.14159').round(3) #=> 3.142
BigDecimal('13345.234').round(-2) #=> 13300

The value of the optional mode argument can be used to determine how rounding is performed; see BigDecimal.mode.

Source: show 

static VALUE
BigDecimal_round(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real   *c, *a;
    int    iLoc = 0;
    VALUE  vLoc;
    VALUE  vRound;
    int    round_to_int = 0;
    size_t mx, pl;

    unsigned short sw = VpGetRoundMode();

    switch (rb_scan_args(argc, argv, "02", &vLoc, &vRound)) {
      case 0:
        iLoc = 0;
        round_to_int = 1;
        break;
      case 1:
        if (RB_TYPE_P(vLoc, T_HASH)) {
            sw = check_rounding_mode_option(vLoc);
        }
        else {
            iLoc = NUM2INT(vLoc);
            if (iLoc < 1) round_to_int = 1;
        }
        break;
      case 2:
        iLoc = NUM2INT(vLoc);
        if (RB_TYPE_P(vRound, T_HASH)) {
            sw = check_rounding_mode_option(vRound);
        }
        else {
            sw = check_rounding_mode(vRound);
        }
        break;
      default:
        break;
    }

    pl = VpSetPrecLimit(0);
    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpSetPrecLimit(pl);
    VpActiveRound(c, a, sw, iLoc);
    if (round_to_int) {
        return BigDecimal_to_i(VpCheckGetValue(c));
    }
    return VpCheckGetValue(c);
}

scale → integer

Returns the number of decimal digits following the decimal digits in self.

BigDecimal("0").scale         # => 0
BigDecimal("1").scale         # => 0
BigDecimal("1.1").scale       # => 1
BigDecimal("3.1415").scale    # => 4
BigDecimal("-1e20").precision # => 0
BigDecimal("1e-20").precision # => 20
BigDecimal("Infinity").scale  # => 0
BigDecimal("-Infinity").scale # => 0
BigDecimal("NaN").scale       # => 0

Source: show 

static VALUE
BigDecimal_scale(VALUE self)
{
    ssize_t scale;
    BigDecimal_count_precision_and_scale(self, NULL, &scale);
    return SSIZET2NUM(scale);
}

sign()

Returns the sign of the value.

Returns a positive value if > 0, a negative value if < 0. It behaves the same with zeros - it returns a positive value for a positive zero (BigDecimal(‘0’)) and a negative value for a negative zero (BigDecimal(‘-0’)).

The specific value returned indicates the type and sign of the BigDecimal, as follows:

BigDecimal::SIGN_NaN

value is Not a Number

BigDecimal::SIGN_POSITIVE_ZERO

value is +0

BigDecimal::SIGN_NEGATIVE_ZERO

value is -0

BigDecimal::SIGN_POSITIVE_INFINITE

value is +Infinity

BigDecimal::SIGN_NEGATIVE_INFINITE

value is -Infinity

BigDecimal::SIGN_POSITIVE_FINITE

value is positive

BigDecimal::SIGN_NEGATIVE_FINITE

value is negative

Source: show 

static VALUE
BigDecimal_sign(VALUE self)
{ /* sign */
    int s = GetVpValue(self, 1)->sign;
    return INT2FIX(s);
}

split()

Splits a BigDecimal number into four parts, returned as an array of values.

The first value represents the sign of the BigDecimal, and is -1 or 1, or 0 if the BigDecimal is Not a Number.

The second value is a string representing the significant digits of the BigDecimal, with no leading zeros.

The third value is the base used for arithmetic (currently always 10) as an Integer.

The fourth value is an Integer exponent.

If the BigDecimal can be represented as 0.xxxxxx*10**n, then xxxxxx is the string of significant digits with no leading zeros, and n is the exponent.

From these values, you can translate a BigDecimal to a float as follows:

sign, significant_digits, base, exponent = a.split
f = sign * "0.#{significant_digits}".to_f * (base ** exponent)

(Note that the to_f method is provided as a more convenient way to translate a BigDecimal to a Float.)

Source: show 

static VALUE
BigDecimal_split(VALUE self)
{
    ENTER(5);
    Real *vp;
    VALUE obj,str;
    ssize_t e, s;
    char *psz1;

    GUARD_OBJ(vp, GetVpValue(self, 1));
    str = rb_str_new(0, VpNumOfChars(vp, "E"));
    psz1 = RSTRING_PTR(str);
    VpSzMantissa(vp, psz1, RSTRING_LEN(str));
    s = 1;
    if(psz1[0] == '-') {
        size_t len = strlen(psz1 + 1);

        memmove(psz1, psz1 + 1, len);
        psz1[len] = '\0';
        s = -1;
    }
    if (psz1[0] == 'N') s = 0; /* NaN */
    e = VpExponent10(vp);
    obj = rb_ary_new2(4);
    rb_ary_push(obj, INT2FIX(s));
    rb_ary_push(obj, str);
    rb_str_resize(str, strlen(psz1));
    rb_ary_push(obj, INT2FIX(10));
    rb_ary_push(obj, SSIZET2NUM(e));
    return obj;
}

sqrt(n)

Returns the square root of the value.

Result has at least n significant digits.

Source: show 

static VALUE
BigDecimal_sqrt(VALUE self, VALUE nFig)
{
    ENTER(5);
    Real *c, *a;
    size_t mx, n;

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);

    n = check_int_precision(nFig);
    n += VpDblFig() + VpBaseFig();
    if (mx <= n) mx = n;
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpSqrt(c, a);
    return VpCheckGetValue(c);
}

sub(value, digits) → bigdecimal

Subtract the specified value.

e.g.

c = a.sub(b,n)
digits

If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.

Source: show 

static VALUE
BigDecimal_sub2(VALUE self, VALUE b, VALUE n)
{
    ENTER(2);
    Real *cv;
    SIGNED_VALUE mx = check_int_precision(n);
    if (mx == 0) return BigDecimal_sub(self, b);
    else {
        size_t pl = VpSetPrecLimit(0);
        VALUE   c = BigDecimal_sub(self, b);
        VpSetPrecLimit(pl);
        GUARD_OBJ(cv, GetVpValue(c, 1));
        VpLeftRound(cv, VpGetRoundMode(), mx);
        return VpCheckGetValue(cv);
    }
}

a.to_d → bigdecimal

Returns self.

require 'bigdecimal/util'

d = BigDecimal("3.14")
d.to_d                       # => 0.314e1

Source: show | on GitHub 

# File ruby/ext/bigdecimal/lib/bigdecimal/util.rb, line 110
def to_d
  self
end

a.to_digits → string

Converts a BigDecimal to a String of the form “nnnnnn.mmm”. This method is deprecated; use BigDecimal#to_s(“F”) instead.

require 'bigdecimal/util'

d = BigDecimal("3.14")
d.to_digits                  # => "3.14"

Source: show | on GitHub 

# File ruby/ext/bigdecimal/lib/bigdecimal/util.rb, line 90
def to_digits
  if self.nan? || self.infinite? || self.zero?
    self.to_s
  else
    i       = self.to_i.to_s
    _,f,_,z = self.frac.split
    i + "." + ("0"*(-z)) + f
  end
end

to_f()

Returns a new Float object having approximately the same value as the BigDecimal number. Normal accuracy limits and built-in errors of binary Float arithmetic apply.

Source: show 

static VALUE
BigDecimal_to_f(VALUE self)
{
    ENTER(1);
    Real *p;
    double d;
    SIGNED_VALUE e;
    char *buf;
    volatile VALUE str;

    GUARD_OBJ(p, GetVpValue(self, 1));
    if (VpVtoD(&d, &e, p) != 1)
        return rb_float_new(d);
    if (e > (SIGNED_VALUE)(DBL_MAX_10_EXP+BASE_FIG))
        goto overflow;
    if (e < (SIGNED_VALUE)(DBL_MIN_10_EXP-BASE_FIG))
        goto underflow;

    str = rb_str_new(0, VpNumOfChars(p, "E"));
    buf = RSTRING_PTR(str);
    VpToString(p, buf, RSTRING_LEN(str), 0, 0);
    errno = 0;
    d = strtod(buf, 0);
    if (errno == ERANGE) {
        if (d == 0.0) goto underflow;
        if (fabs(d) >= HUGE_VAL) goto overflow;
    }
    return rb_float_new(d);

overflow:
    VpException(VP_EXCEPTION_OVERFLOW, "BigDecimal to Float conversion", 0);
    if (BIGDECIMAL_NEGATIVE_P(p))
        return rb_float_new(VpGetDoubleNegInf());
    else
        return rb_float_new(VpGetDoublePosInf());

underflow:
    VpException(VP_EXCEPTION_UNDERFLOW, "BigDecimal to Float conversion", 0);
    if (BIGDECIMAL_NEGATIVE_P(p))
        return rb_float_new(-0.0);
    else
        return rb_float_new(0.0);
}

to_i()

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.

Also aliased as: to_int

Source: show 

static VALUE
BigDecimal_to_i(VALUE self)
{
    ENTER(5);
    ssize_t e, nf;
    Real *p;

    GUARD_OBJ(p, GetVpValue(self, 1));
    BigDecimal_check_num(p);

    e = VpExponent10(p);
    if (e <= 0) return INT2FIX(0);
    nf = VpBaseFig();
    if (e <= nf) {
        return LONG2NUM((long)(VpGetSign(p) * (DECDIG_DBL_SIGNED)p->frac[0]));
    }
    else {
        VALUE a = BigDecimal_split(self);
        VALUE digits = RARRAY_AREF(a, 1);
        VALUE numerator = rb_funcall(digits, rb_intern("to_i"), 0);
        VALUE ret;
        ssize_t dpower = e - (ssize_t)RSTRING_LEN(digits);

        if (BIGDECIMAL_NEGATIVE_P(p)) {
            numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1));
        }
        if (dpower < 0) {
            ret = rb_funcall(numerator, rb_intern("div"), 1,
                              rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                         INT2FIX(-dpower)));
        }
        else {
            ret = rb_funcall(numerator, '*', 1,
                             rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                        INT2FIX(dpower)));
        }
        if (RB_TYPE_P(ret, T_FLOAT)) {
            rb_raise(rb_eFloatDomainError, "Infinity");
        }
        return ret;
    }
}

to_int()

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.

Alias for: to_i

to_json(*args)

Returns a JSON string representing self:

require 'json/add/bigdecimal'
puts BigDecimal(2).to_json
puts BigDecimal(2.0, 4).to_json
puts BigDecimal(Complex(2, 0)).to_json

Output:

{"json_class":"BigDecimal","b":"27:0.2e1"}
{"json_class":"BigDecimal","b":"36:0.2e1"}
{"json_class":"BigDecimal","b":"27:0.2e1"}

Source: show | on GitHub 

# File ruby/ext/json/lib/json/add/bigdecimal.rb, line 55
def to_json(*args)
  as_json.to_json(*args)
end

to_r()

Converts a BigDecimal to a Rational.

Source: show 

static VALUE
BigDecimal_to_r(VALUE self)
{
    Real *p;
    ssize_t sign, power, denomi_power;
    VALUE a, digits, numerator;

    p = GetVpValue(self, 1);
    BigDecimal_check_num(p);

    sign = VpGetSign(p);
    power = VpExponent10(p);
    a = BigDecimal_split(self);
    digits = RARRAY_AREF(a, 1);
    denomi_power = power - RSTRING_LEN(digits);
    numerator = rb_funcall(digits, rb_intern("to_i"), 0);

    if (sign < 0) {
        numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1));
    }
    if (denomi_power < 0) {
        return rb_Rational(numerator,
                           rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                      INT2FIX(-denomi_power)));
    }
    else {
        return rb_Rational1(rb_funcall(numerator, '*', 1,
                                       rb_funcall(INT2FIX(10), rb_intern("**"), 1,
                                                  INT2FIX(denomi_power))));
    }
}

to_s(s)

Converts the value to a string.

The default format looks like 0.xxxxEnn.

The optional parameter s consists of either an integer; or an optional ‘+’ or ‘ ’, followed by an optional number, followed by an optional ‘E’ or ‘F’.

If there is a ‘+’ at the start of s, positive values are returned with a leading ‘+’.

A space at the start of s returns positive values with a leading space.

If s contains a number, a space is inserted after each group of that many digits, starting from ‘.’ and counting outwards.

If s ends with an ‘E’, engineering notation (0.xxxxEnn) is used.

If s ends with an ‘F’, conventional floating point notation is used.

Examples:

BigDecimal('-1234567890123.45678901234567890').to_s('5F')
  #=> '-123 45678 90123.45678 90123 45678 9'

BigDecimal('1234567890123.45678901234567890').to_s('+8F')
  #=> '+12345 67890123.45678901 23456789'

BigDecimal('1234567890123.45678901234567890').to_s(' F')
  #=> ' 1234567890123.4567890123456789'

Source: show 

static VALUE
BigDecimal_to_s(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    int   fmt = 0;   /* 0: E format, 1: F format */
    int   fPlus = 0; /* 0: default, 1: set ' ' before digits, 2: set '+' before digits. */
    Real  *vp;
    volatile VALUE str;
    char  *psz;
    char   ch;
    size_t nc, mc = 0;
    SIGNED_VALUE m;
    VALUE  f;

    GUARD_OBJ(vp, GetVpValue(self, 1));

    if (rb_scan_args(argc, argv, "01", &f) == 1) {
        if (RB_TYPE_P(f, T_STRING)) {
            psz = StringValueCStr(f);
            if (*psz == ' ') {
                fPlus = 1;
                psz++;
            }
            else if (*psz == '+') {
                fPlus = 2;
                psz++;
            }
            while ((ch = *psz++) != 0) {
                if (ISSPACE(ch)) {
                    continue;
                }
                if (!ISDIGIT(ch)) {
                    if (ch == 'F' || ch == 'f') {
                        fmt = 1; /* F format */
                    }
                    break;
                }
                mc = mc*10 + ch - '0';
            }
        }
        else {
            m = NUM2INT(f);
            if (m <= 0) {
                rb_raise(rb_eArgError, "argument must be positive");
            }
            mc = (size_t)m;
        }
    }
    if (fmt) {
        nc = VpNumOfChars(vp, "F");
    }
    else {
        nc = VpNumOfChars(vp, "E");
    }
    if (mc > 0) {
        nc += (nc + mc - 1) / mc + 1;
    }

    str = rb_usascii_str_new(0, nc);
    psz = RSTRING_PTR(str);

    if (fmt) {
        VpToFString(vp, psz, RSTRING_LEN(str), mc, fPlus);
    }
    else {
        VpToString (vp, psz, RSTRING_LEN(str), mc, fPlus);
    }
    rb_str_resize(str, strlen(psz));
    return str;
}

truncate(n)

Truncate to the nearest integer (by default), returning the result as a BigDecimal.

BigDecimal('3.14159').truncate #=> 3
BigDecimal('8.7').truncate #=> 8
BigDecimal('-9.9').truncate #=> -9

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal('3.14159').truncate(3) #=> 3.141
BigDecimal('13345.234').truncate(-2) #=> 13300.0

Source: show 

static VALUE
BigDecimal_truncate(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real *c, *a;
    int iLoc;
    VALUE vLoc;
    size_t mx, pl = VpSetPrecLimit(0);

    if (rb_scan_args(argc, argv, "01", &vLoc) == 0) {
        iLoc = 0;
    }
    else {
        iLoc = NUM2INT(vLoc);
    }

    GUARD_OBJ(a, GetVpValue(self, 1));
    mx = a->Prec * (VpBaseFig() + 1);
    GUARD_OBJ(c, NewZeroWrapLimited(1, mx));
    VpSetPrecLimit(pl);
    VpActiveRound(c, a, VP_ROUND_DOWN, iLoc); /* 0: truncate */
    if (argc == 0) {
        return BigDecimal_to_i(VpCheckGetValue(c));
    }
    return VpCheckGetValue(c);
}

zero?()

Returns True if the value is zero.

Source: show 

static VALUE
BigDecimal_zero(VALUE self)
{
    Real *a = GetVpValue(self, 1);
    return VpIsZero(a) ? Qtrue : Qfalse;
}