Class: BigDecimal

Inherits:
Numeric
  • Object
show all
Defined in:
lib/bigdecimal/util.rb,
bigdecimal.c

Overview

BigDecimal provides arbitrary-precision floating point decimal arithmetic.

Copyright © 2002 by Shigeo Kobayashi <[email protected]>. You may distribute under the terms of either the GNU General Public License or the Artistic License, as specified in the README file of the BigDecimal distribution.

Documented by mathew <[email protected]>.

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
for i in (1..10000)
  sum = sum + 0.0001
end
print sum

and contrast with the output from:

require 'bigdecimal'

sum = BigDecimal.new("0")
for i in (1..10000)
  sum = sum + BigDecimal.new("0.0001")
end
print sum

Similarly:

(BigDecimal.new(“1.2”) - BigDecimal(“1.0”)) == BigDecimal(“0.2”) -> true

(1.2 - 1.0) == 0.2 -> false

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.new(“1.0”) / BigDecimal.new(“0.0”) -> infinity

BigDecimal.new(“-1.0”) / BigDecimal.new(“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.new(“0.0”) / BigDecimal.new(“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.new(‘NaN’)

n == 0.0 -> nil

n == n -> nil

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

BigDecimal.new(“1.0”) / BigDecimal.new(“-Infinity”) -> -0.0

BigDecimal.new(“1.0”) / BigDecimal.new(“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.

Constant Summary collapse

BASE =

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.)

INT2FIX((S_INT)VpBaseVal())
EXCEPTION_ALL =

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

0xff
EXCEPTION_NaN =

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

0x02
EXCEPTION_INFINITY =

Determines what happens when the result of a computation is infinity. See BigDecimal.mode.

0x01
EXCEPTION_UNDERFLOW =

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

0x04
EXCEPTION_OVERFLOW =

Determines what happens when the result of a computation is an underflow (a result too large to be represented). See BigDecimal.mode.

0x01
EXCEPTION_ZERODIVIDE =

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

0x01
ROUND_MODE =

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

0x100
ROUND_UP =

Indicates that values should be rounded away from zero. See BigDecimal.mode.

1
ROUND_DOWN =

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

2
ROUND_HALF_UP =

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

3
ROUND_HALF_DOWN =

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

4
ROUND_CEILING =

Round towards +infinity. See BigDecimal.mode.

5
ROUND_FLOOR =

Round towards -infinity. See BigDecimal.mode.

6
ROUND_HALF_EVEN =

Round towards the even neighbor. See BigDecimal.mode.

7
SIGN_NaN =

Indicates that a value is not a number. See BigDecimal.sign.

0
SIGN_POSITIVE_ZERO =

Indicates that a value is +0. See BigDecimal.sign.

1
SIGN_NEGATIVE_ZERO =

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

-1
SIGN_POSITIVE_FINITE =

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

2
SIGN_NEGATIVE_FINITE =

Indicates that a value is negative and finite. See BigDecimal.sign.

-2
SIGN_POSITIVE_INFINITE =

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

3
SIGN_NEGATIVE_INFINITE =

Indicates that a value is negative and infinite. See BigDecimal.sign.

-3

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

._load(str) ⇒ Object

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



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# File 'bigdecimal.c', line 325

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

    SafeStringValue(str);
    pch = (unsigned char *)RSTRING_PTR(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));
    m /= VpBaseFig();
    if(m && pv->MaxPrec>m) pv->MaxPrec = m+1;
    return ToValue(pv);
}

.double_fig ⇒ Object

BigDecimal.double_fig

The BigDecimal.double_fig class method returns the number of digits a Float number is allowed to have. The result depends upon the CPU and OS in use.



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# File 'bigdecimal.c', line 257

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

.induced_from(x) ⇒ Object 



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# File 'bigdecimal.c', line 573

static VALUE
BigDecimal_induced_from(VALUE self, VALUE x)
{
    Real *p = GetVpValue(x,1);
    return p->obj;
}

.limit(*args) ⇒ Object

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 priority over any limit specified to instance methods such as ceil, floor, truncate, or round.



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# File 'bigdecimal.c', line 1729

static VALUE
BigDecimal_limit(int argc, VALUE *argv, VALUE self)
{
    VALUE  nFig;
    VALUE  nCur = INT2NUM(VpGetPrecLimit());

    if(rb_scan_args(argc,argv,"01",&nFig)==1) {
        int nf;
        if(nFig==Qnil) return nCur;
        Check_Type(nFig, T_FIXNUM);
        nf = FIX2INT(nFig);
        if(nf<0) {
            rb_raise(rb_eArgError, "argument must be positive");
        }
        VpSetPrecLimit(nf);
    }
    return nCur;
}

.mode(*args) ⇒ Object

BigDecimal.mode(mode, value)

Controls handling of arithmetic exceptions and rounding. If no value is supplied, the current value is returned.

Six values of the mode parameter control the handling of arithmetic exceptions:

BigDecimal::EXCEPTION_NaN BigDecimal::EXCEPTION_INFINITY BigDecimal::EXCEPTION_UNDERFLOW BigDecimal::EXCEPTION_OVERFLOW BigDecimal::EXCEPTION_ZERODIVIDE BigDecimal::EXCEPTION_ALL

For each mode parameter above, if the value set is false, computation continues after an arithmetic exception of the appropriate type. When computation continues, results are as follows:

EXCEPTION_NaN

NaN

EXCEPTION_INFINITY

+infinity or -infinity

EXCEPTION_UNDERFLOW

0

EXCEPTION_OVERFLOW

+infinity or -infinity

EXCEPTION_ZERODIVIDE

+infinity or -infinity

One value of the mode parameter controls the rounding of numeric values: BigDecimal::ROUND_MODE. The values it can take are:

ROUND_UP

round away from zero

ROUND_DOWN

round towards zero (truncate)

ROUND_HALF_UP

round up if the appropriate digit >= 5, otherwise truncate (default)

ROUND_HALF_DOWN

round up if the appropriate digit >= 6, otherwise truncate

ROUND_HALF_EVEN

round towards the even neighbor (Banker’s rounding)

ROUND_CEILING

round towards positive infinity (ceil)

ROUND_FLOOR

round towards negative infinity (floor)



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# File 'bigdecimal.c', line 388

static VALUE
BigDecimal_mode(int argc, VALUE *argv, VALUE self)
{
    VALUE which;
    VALUE val;
    unsigned long f,fo;
 
    if(rb_scan_args(argc,argv,"11",&which,&val)==1) val = Qnil;

    Check_Type(which, T_FIXNUM);
    f = (unsigned long)FIX2INT(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_eTypeError, "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))));
        }
        if(f&VP_EXCEPTION_NaN) {
            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_NaN):
                           (fo&(~VP_EXCEPTION_NaN))));
        }
        fo = VpGetException();
        return INT2FIX(fo);
    }
    if(VP_ROUND_MODE==f) {
        /* Rounding mode setting */
        fo = VpGetRoundMode();
        if(val==Qnil) return INT2FIX(fo);
        Check_Type(val, T_FIXNUM);
        if(!VpIsRoundMode(FIX2INT(val))) {
            rb_raise(rb_eTypeError, "invalid rounding mode");
            return Qnil;
        }
        fo = VpSetRoundMode((unsigned long)FIX2INT(val));
        return INT2FIX(fo);
    }
    rb_raise(rb_eTypeError, "first argument for BigDecimal#mode invalid");
    return Qnil;
}

.new(*args) ⇒ Object

new(initial, digits)

Create a new BigDecimal object.

initial

The initial value, as a String. Spaces are ignored, unrecognized characters terminate the value.

digits

The number of significant digits, as a Fixnum. If omitted or 0, the number of significant digits is determined from the initial value.

The actual number of significant digits used in computation is usually larger than the specified number.



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# File 'bigdecimal.c', line 1698

static VALUE
BigDecimal_new(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    Real *pv;
    S_LONG mf;
    VALUE  nFig;
    VALUE  iniValue;

    if(rb_scan_args(argc,argv,"11",&iniValue,&nFig)==1) {
        mf = 0;
    } else {
        mf = GetPositiveInt(nFig);
    }
    SafeStringValue(iniValue);
    GUARD_OBJ(pv,VpNewRbClass(mf, RSTRING_PTR(iniValue),self));
    return ToValue(pv);
}

.ver ⇒ Object

Returns the BigDecimal version number.

Ruby 1.8.0 returns 1.0.0. Ruby 1.8.1 thru 1.8.3 return 1.0.1.



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# File 'bigdecimal.c', line 162

static VALUE
BigDecimal_version(VALUE self)
{
    /*
     * 1.0.0: Ruby 1.8.0
     * 1.0.1: Ruby 1.8.1
    */
    return rb_str_new2("1.0.1");
}

Instance Method Details

#% ⇒ Object

%: a%b = a - (a.to_f/b).floor * b



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# File 'bigdecimal.c', line 996

static VALUE
BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */
{
    ENTER(3);
    VALUE obj;
    Real *div=NULL, *mod=NULL;

    obj = BigDecimal_DoDivmod(self,r,&div,&mod);
    if(obj!=(VALUE)0) return obj;
    SAVE(div);SAVE(mod);
    return ToValue(mod);
}

#*(r) ⇒ Object

mult(value, digits)

Multiply by the specified value.

e.g.

c = a.mult(b,n)
c = a * b
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.



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# File 'bigdecimal.c', line 857

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

    GUARD_OBJ(a,GetVpValue(self,1));
    b = GetVpValue(r,0);
    if(!b) return DoSomeOne(self,r);
    SAVE(b);

    mx = a->Prec + b->Prec;
    GUARD_OBJ(c,VpCreateRbObject(mx *(VpBaseFig() + 1), "0"));
    VpMult(c, a, b);
    return ToValue(c);
}

#**(p) ⇒ Object

power(n)

Returns the value raised to the power of n. Note that n must be an Integer.

Also available as the operator **



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# File 'bigdecimal.c', line 1643

static VALUE
BigDecimal_power(VALUE self, VALUE p)
{
    ENTER(5);
    Real *x, *y;
    S_LONG mp, ma, n;

    Check_Type(p, T_FIXNUM);
    n = FIX2INT(p);
    ma = n;
    if(ma < 0)  ma = -ma;
    if(ma == 0) ma = 1;

    GUARD_OBJ(x,GetVpValue(self,1));
    if(VpIsDef(x)) {
        mp = x->Prec *(VpBaseFig() + 1);
        GUARD_OBJ(y,VpCreateRbObject(mp *(ma + 1), "0"));
    } else {
        GUARD_OBJ(y,VpCreateRbObject(1, "0"));
    }
    VpPower(y, x, n);
    return ToValue(y);
}

#+(r) ⇒ Object

add(value, digits)

Add the specified value.

e.g.

c = a.add(b,n)
c = a + b
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.



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# File 'bigdecimal.c', line 653

static VALUE
BigDecimal_add(VALUE self, VALUE r)
{
    ENTER(5);
    Real *c, *a, *b;
    U_LONG mx;
    GUARD_OBJ(a,GetVpValue(self,1));
    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==(-1L)) {
        GUARD_OBJ(c,VpCreateRbObject(VpBaseFig() + 1, "0"));
        VpAddSub(c, a, b, 1);
    } else {
        GUARD_OBJ(c,VpCreateRbObject(mx *(VpBaseFig() + 1), "0"));
        if(!mx) {
            VpSetInf(c,VpGetSign(a));
        } else {
            VpAddSub(c, a, b, 1);
        }
    }
    return ToValue(c);
}

#+@ ⇒ Object 



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# File 'bigdecimal.c', line 636

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

#-(r) ⇒ Object

sub(value, digits)

Subtract the specified value.

e.g.

c = a.sub(b,n)
c = a - b
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.



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# File 'bigdecimal.c', line 691

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

    GUARD_OBJ(a,GetVpValue(self,1));
    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==(-1L)) {
        GUARD_OBJ(c,VpCreateRbObject(VpBaseFig() + 1, "0"));
        VpAddSub(c, a, b, -1);
    } else {
        GUARD_OBJ(c,VpCreateRbObject(mx *(VpBaseFig() + 1), "0"));
        if(!mx) {
            VpSetInf(c,VpGetSign(a));
        } else {
            VpAddSub(c, a, b, -1);
        }
    }
    return ToValue(c);
}

#-@ ⇒ Object 



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# File 'bigdecimal.c', line 835

static VALUE
BigDecimal_neg(VALUE self)
{
    ENTER(5);
    Real *c, *a;
    GUARD_OBJ(a,GetVpValue(self,1));
    GUARD_OBJ(c,VpCreateRbObject(a->Prec *(VpBaseFig() + 1), "0"));
    VpAsgn(c, a, -1);
    return ToValue(c);
}

#/ ⇒ Object

For c = self/r: with round operation



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# File 'bigdecimal.c', line 912

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(&c, &res, &div, self, r);
    if(r!=(VALUE)0) 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],(VpBaseVal()*res->frac[0])/div->frac[0]);
    }
    return ToValue(c);
}

#<(r) ⇒ Object

a < b

Returns true if a is less than b. Values may be coerced to perform the comparison (see ==, coerce).



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# File 'bigdecimal.c', line 793

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

#<=(r) ⇒ Object

a <= b

Returns true if a is less than or equal to b. Values may be coerced to perform the comparison (see ==, coerce).



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# File 'bigdecimal.c', line 805

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

#<=>(r) ⇒ Object

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



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# File 'bigdecimal.c', line 765

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

#==(r) ⇒ Object

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.new(‘1.0’) == 1.0 -> true



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# File 'bigdecimal.c', line 781

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

#===(r) ⇒ Object

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.new(‘1.0’) == 1.0 -> true



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# File 'bigdecimal.c', line 781

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

#>(r) ⇒ Object

a > b

Returns true if a is greater than b. Values may be coerced to perform the comparison (see ==, coerce).



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# File 'bigdecimal.c', line 817

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

#>=(r) ⇒ Object

a >= b

Returns true if a is greater than or equal to b. Values may be coerced to perform the comparison (see ==, coerce)



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# File 'bigdecimal.c', line 829

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

#_dump(*args) ⇒ Object 



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# File 'bigdecimal.c', line 305

static VALUE
BigDecimal_dump(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    char sz[50];
    Real *vp;
    char *psz;
    VALUE dummy;
    rb_scan_args(argc, argv, "01", &dummy);
    GUARD_OBJ(vp,GetVpValue(self,1));
    sprintf(sz,"%lu:",VpMaxPrec(vp)*VpBaseFig());
    psz = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp,"E")+strlen(sz));
    sprintf(psz,"%s",sz);
    VpToString(vp, psz+strlen(psz), 0, 0);
    return rb_str_new2(psz);
}

#abs ⇒ Object

Returns the absolute value.

BigDecimal(‘5’).abs -> 5

BigDecimal(‘-3’).abs -> 3



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# File 'bigdecimal.c', line 1189

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

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpAsgn(c, a, 1);
    VpChangeSign(c,(S_INT)1);
    return ToValue(c);
}

#add(b, n) ⇒ Object 



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# File 'bigdecimal.c', line 1132

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

#ceil(*args) ⇒ Object

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



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# File 'bigdecimal.c', line 1432

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

    if(rb_scan_args(argc,argv,"01",&vLoc)==0) {
        iLoc = 0;
    } else {
        Check_Type(vLoc, T_FIXNUM);
        iLoc = FIX2INT(vLoc);
    }

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSetPrecLimit(pl);
    VpActiveRound(c,a,VP_ROUND_CEIL,iLoc);
    return ToValue(c);
}

#coerce(other) ⇒ Object

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.new(“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.



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# File 'bigdecimal.c', line 621

static VALUE
BigDecimal_coerce(VALUE self, VALUE other)
{
    ENTER(2);
    VALUE obj;
    Real *b;
    if(TYPE(other) == T_FLOAT) {
       obj = rb_assoc_new(other, BigDecimal_to_f(self));
    } else {
       GUARD_OBJ(b,GetVpValue(other,1));
       obj = rb_assoc_new(b->obj, self);
    }
    return obj;
}

#div(*args) ⇒ Object 



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# File 'bigdecimal.c', line 1096

static VALUE
BigDecimal_div2(int argc, VALUE *argv, VALUE self)
{
    ENTER(5);
    VALUE b,n;
    int na = rb_scan_args(argc,argv,"11",&b,&n);
    if(na==1) { /* div in Float sense */
       VALUE obj;
       Real *div=NULL;
       Real *mod;
       obj = BigDecimal_DoDivmod(self,b,&div,&mod);
       if(obj!=(VALUE)0) return obj;
       return ToValue(div);
    } else {    /* div in BigDecimal sense */
       U_LONG ix = (U_LONG)GetPositiveInt(n);
       if(ix==0) return BigDecimal_div(self,b);
       else {
          Real *res=NULL;
          Real *av=NULL, *bv=NULL, *cv=NULL;
          U_LONG mx = (ix+VpBaseFig()*2);
          U_LONG pl = VpSetPrecLimit(0);

          GUARD_OBJ(cv,VpCreateRbObject(mx,"0"));
          GUARD_OBJ(av,GetVpValue(self,1));
          GUARD_OBJ(bv,GetVpValue(b,1));
          mx = av->Prec + bv->Prec + 2;
          if(mx <= cv->MaxPrec) mx = cv->MaxPrec+1;
          GUARD_OBJ(res,VpCreateRbObject((mx * 2  + 2)*VpBaseFig(), "#0"));
          VpDivd(cv,res,av,bv);
          VpSetPrecLimit(pl);
          VpLeftRound(cv,VpGetRoundMode(),ix);
          return ToValue(cv);
       }
    }
}

#divmod(r) ⇒ Object

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.new(“42”) b = BigDecimal.new(“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.



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# File 'bigdecimal.c', line 1082

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

    obj = BigDecimal_DoDivmod(self,r,&div,&mod);
    if(obj!=(VALUE)0) return obj;
    SAVE(div);SAVE(mod);
    obj = rb_assoc_new(ToValue(div), ToValue(mod));
    return obj;
}

#eql?(r) ⇒ Boolean

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.new(‘1.0’) == 1.0 -> true

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 781

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

#exponent ⇒ Object

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.



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# File 'bigdecimal.c', line 1597

static VALUE
BigDecimal_exponent(VALUE self)
{
    S_LONG e = VpExponent10(GetVpValue(self,1));
    return INT2NUM(e);
}

#finite? ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 504

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

#fix ⇒ Object

Return the integer part of the number.



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# File 'bigdecimal.c', line 1230

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

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

#floor(*args) ⇒ Object

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



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# File 'bigdecimal.c', line 1388

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

    if(rb_scan_args(argc,argv,"01",&vLoc)==0) {
        iLoc = 0;
    } else {
        Check_Type(vLoc, T_FIXNUM);
        iLoc = FIX2INT(vLoc);
    }

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSetPrecLimit(pl);
    VpActiveRound(c,a,VP_ROUND_FLOOR,iLoc);
    return ToValue(c);
}

#frac ⇒ Object

Return the fractional part of the number.



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# File 'bigdecimal.c', line 1355

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

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpFrac(c, a);
    return ToValue(c);
}

#hash ⇒ Object 



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# File 'bigdecimal.c', line 285

static VALUE
BigDecimal_hash(VALUE self)
{
    ENTER(1);
    Real *p;
    U_LONG hash,i;

    GUARD_OBJ(p,GetVpValue(self,1));
    hash = (U_LONG)p->sign;
    /* hash!=2: the case for 0(1),NaN(0) or +-Infinity(3) is sign itself */
    if(hash==2) {
        for(i = 0; i < p->Prec;i++) {
            hash = 31 * hash + p->frac[i];
            hash ^= p->frac[i];
        }
        hash += p->exponent;
    }
    return INT2FIX(hash);
}

#infinite? ⇒ Boolean

Returns True if the value is infinite

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 494

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 ⇒ Object

Returns debugging information about the value as a string of comma-separated values in angle brackets with a leading #:

BigDecimal.new(“1234.5678”).inspect -> “#<BigDecimal:b7ea1130,‘0.12345678E4’,8(12)>”

The first part is the address, the second is the value as a string, and the final part ss(mm) is the current number of significant digits and the maximum number of significant digits, respectively.



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# File 'bigdecimal.c', line 1614

static VALUE
BigDecimal_inspect(VALUE self)
{
    ENTER(5);
    Real *vp;
    VALUE obj;
    unsigned int nc;
    char *psz1;
    char *pszAll;

    GUARD_OBJ(vp,GetVpValue(self,1));
    nc = VpNumOfChars(vp,"E");
    nc +=(nc + 9) / 10;

    psz1   = ALLOCA_N(char,nc);
    pszAll = ALLOCA_N(char,nc+256);
    VpToString(vp, psz1, 10, 0);
    sprintf(pszAll,"#<BigDecimal:%lx,'%s',%lu(%lu)>",self,psz1,VpPrec(vp)*VpBaseFig(),VpMaxPrec(vp)*VpBaseFig());
    obj = rb_str_new2(pszAll);
    return obj;
}

#modulo ⇒ Object

%: a%b = a - (a.to_f/b).floor * b



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# File 'bigdecimal.c', line 996

static VALUE
BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */
{
    ENTER(3);
    VALUE obj;
    Real *div=NULL, *mod=NULL;

    obj = BigDecimal_DoDivmod(self,r,&div,&mod);
    if(obj!=(VALUE)0) return obj;
    SAVE(div);SAVE(mod);
    return ToValue(mod);
}

#mult(b, n) ⇒ Object 



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# File 'bigdecimal.c', line 1166

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

#nan? ⇒ Boolean

Returns True if the value is Not a Number

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 485

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

#nonzero? ⇒ Boolean

Returns True if the value is non-zero.

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 755

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

#power(p) ⇒ Object

power(n)

Returns the value raised to the power of n. Note that n must be an Integer.

Also available as the operator **



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# File 'bigdecimal.c', line 1643

static VALUE
BigDecimal_power(VALUE self, VALUE p)
{
    ENTER(5);
    Real *x, *y;
    S_LONG mp, ma, n;

    Check_Type(p, T_FIXNUM);
    n = FIX2INT(p);
    ma = n;
    if(ma < 0)  ma = -ma;
    if(ma == 0) ma = 1;

    GUARD_OBJ(x,GetVpValue(self,1));
    if(VpIsDef(x)) {
        mp = x->Prec *(VpBaseFig() + 1);
        GUARD_OBJ(y,VpCreateRbObject(mp *(ma + 1), "0"));
    } else {
        GUARD_OBJ(y,VpCreateRbObject(1, "0"));
    }
    VpPower(y, x, n);
    return ToValue(y);
}

#precs ⇒ Object

precs

Returns an Array of two Integer values.

The first value is the current number of significant digits in the BigDecimal. The second value is the maximum number of significant digits for the BigDecimal.



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# File 'bigdecimal.c', line 272

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

    GUARD_OBJ(p,GetVpValue(self,1));
    obj = rb_assoc_new(INT2NUM(p->Prec*VpBaseFig()),
           INT2NUM(p->MaxPrec*VpBaseFig()));
    return obj;
}

#quo ⇒ Object

For c = self/r: with round operation



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# File 'bigdecimal.c', line 912

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(&c, &res, &div, self, r);
    if(r!=(VALUE)0) 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],(VpBaseVal()*res->frac[0])/div->frac[0]);
    }
    return ToValue(c);
}

#remainder ⇒ Object

remainder



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# File 'bigdecimal.c', line 1053

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

#round(*args) ⇒ Object

round(n,mode)

Round to the nearest 1 (by default), returning the result as a BigDecimal.

BigDecimal(‘3.14159’).round -> 3

BigDecimal(‘8.7’).round -> 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’).round(3) -> 3.142

BigDecimal(‘13345.234’).round(-2) -> 13300.0

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



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# File 'bigdecimal.c', line 1266

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

    int    sw = VpGetRoundMode();

    int na = rb_scan_args(argc,argv,"02",&vLoc,&vRound);
    switch(na) {
    case 0:
        iLoc = 0;
        break;
    case 1:
        Check_Type(vLoc, T_FIXNUM);
        iLoc = FIX2INT(vLoc);
        break;
    case 2:
        Check_Type(vLoc, T_FIXNUM);
        iLoc = FIX2INT(vLoc);
        Check_Type(vRound, T_FIXNUM);
        sw   = FIX2INT(vRound);
        if(!VpIsRoundMode(sw)) {
            rb_raise(rb_eTypeError, "invalid rounding mode");
            return Qnil;
        }
        break;
    }

    pl = VpSetPrecLimit(0);
    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSetPrecLimit(pl);
    VpActiveRound(c,a,sw,iLoc);
    return ToValue(c);
}

#sign ⇒ Object

Returns the sign of the value.

Returns a positive value if > 0, a negative value if < 0, and a zero if == 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



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# File 'bigdecimal.c', line 1764

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

#split ⇒ Object

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.)



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# File 'bigdecimal.c', line 1564

static VALUE
BigDecimal_split(VALUE self)
{
    ENTER(5);
    Real *vp;
    VALUE obj,obj1;
    S_LONG e;
    S_LONG s;
    char *psz1;

    GUARD_OBJ(vp,GetVpValue(self,1));
    psz1 = ALLOCA_N(char,(unsigned int)VpNumOfChars(vp,"E"));
    VpSzMantissa(vp,psz1);
    s = 1;
    if(psz1[0]=='-') {
        s = -1; ++psz1;
    }
    if(psz1[0]=='N') s=0; /* NaN */
    e = VpExponent10(vp);
    obj1 = rb_str_new2(psz1);
    obj  = rb_ary_new2(4);
    rb_ary_push(obj, INT2FIX(s));
    rb_ary_push(obj, obj1);
    rb_ary_push(obj, INT2FIX(10));
    rb_ary_push(obj, INT2NUM(e));
    return obj;
}

#sqrt(nFig) ⇒ Object

sqrt(n)

Returns the square root of the value.

If n is specified, returns at least that many significant digits.



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# File 'bigdecimal.c', line 1211

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

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

    n = GetPositiveInt(nFig) + VpDblFig() + 1;
    if(mx <= n) mx = n;
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSqrt(c, a);
    return ToValue(c);
}

#sub(b, n) ⇒ Object 



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# File 'bigdecimal.c', line 1149

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

#to_digits ⇒ Object

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



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# File 'lib/bigdecimal/util.rb', line 33

def to_digits
   if self.nan? || self.infinite? || self.zero?
      self.to_s
   else
     i       = self.to_i.to_s
     s,f,y,z = self.frac.split
     i + "." + ("0"*(-z)) + f
   end
end

#to_f ⇒ Object

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.



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# File 'bigdecimal.c', line 584

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

    GUARD_OBJ(p,GetVpValue(self,1));
    if(VpVtoD(&d, &e, p)!=1) return rb_float_new(d);
    buf = ALLOCA_N(char,(unsigned int)VpNumOfChars(p,"E"));
    VpToString(p, buf, 0, 0);
    errno = 0;
    d = strtod(buf, 0);
    if(errno == ERANGE) {
       VpException(VP_EXCEPTION_OVERFLOW,"BigDecimal to Float conversion",0);
       if(d>0.0) return rb_float_new(DBL_MAX);
       else      return rb_float_new(-DBL_MAX);
    }
    return rb_float_new(d);
}

#to_i ⇒ Object

Returns the value as an integer (Fixnum or Bignum).

If the BigNumber is infinity or NaN, returns nil.



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# File 'bigdecimal.c', line 517

static VALUE
BigDecimal_to_i(VALUE self)
{
    ENTER(5);
    int e,n,i,nf;
    U_LONG v,b,j;
    char *psz,*pch;
    Real *p;

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

    /* Infinity or NaN not converted. */
    if(VpIsNaN(p)) {
       VpException(VP_EXCEPTION_NaN,"Computation results to 'NaN'(Not a Number)",0);
       return Qnil;
    } else if(VpIsPosInf(p)) {
       VpException(VP_EXCEPTION_INFINITY,"Computation results to 'Infinity'",0);
       return Qnil;
    } else if(VpIsNegInf(p)) {
       VpException(VP_EXCEPTION_INFINITY,"Computation results to '-Infinity'",0);
       return Qnil;
    }

    e = VpExponent10(p);
    if(e<=0) return INT2FIX(0);
    nf = VpBaseFig();
    if(e<=nf) {
        e = VpGetSign(p)*p->frac[0];
        return INT2FIX(e);
    }
    psz = ALLOCA_N(char,(unsigned int)(e+nf+2));

    n = (e+nf-1)/nf;
    pch = psz;
    if(VpGetSign(p)<0) *pch++ = '-';
    for(i=0;i<n;++i) {
        b = VpBaseVal()/10;
        if(i>=(int)p->Prec) {
            while(b) {
                *pch++ = '0';
                b /= 10;
            }
            continue;
        }
        v = p->frac[i];
        while(b) {
            j = v/b;
            *pch++ = (char)(j + '0');
            v -= j*b;
            b /= 10;
        }
    }
    *pch++ = 0;
    return rb_cstr2inum(psz,10);
}

#to_int ⇒ Object

Returns the value as an integer (Fixnum or Bignum).

If the BigNumber is infinity or NaN, returns nil.



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# File 'bigdecimal.c', line 517

static VALUE
BigDecimal_to_i(VALUE self)
{
    ENTER(5);
    int e,n,i,nf;
    U_LONG v,b,j;
    char *psz,*pch;
    Real *p;

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

    /* Infinity or NaN not converted. */
    if(VpIsNaN(p)) {
       VpException(VP_EXCEPTION_NaN,"Computation results to 'NaN'(Not a Number)",0);
       return Qnil;
    } else if(VpIsPosInf(p)) {
       VpException(VP_EXCEPTION_INFINITY,"Computation results to 'Infinity'",0);
       return Qnil;
    } else if(VpIsNegInf(p)) {
       VpException(VP_EXCEPTION_INFINITY,"Computation results to '-Infinity'",0);
       return Qnil;
    }

    e = VpExponent10(p);
    if(e<=0) return INT2FIX(0);
    nf = VpBaseFig();
    if(e<=nf) {
        e = VpGetSign(p)*p->frac[0];
        return INT2FIX(e);
    }
    psz = ALLOCA_N(char,(unsigned int)(e+nf+2));

    n = (e+nf-1)/nf;
    pch = psz;
    if(VpGetSign(p)<0) *pch++ = '-';
    for(i=0;i<n;++i) {
        b = VpBaseVal()/10;
        if(i>=(int)p->Prec) {
            while(b) {
                *pch++ = '0';
                b /= 10;
            }
            continue;
        }
        v = p->frac[i];
        while(b) {
            j = v/b;
            *pch++ = (char)(j + '0');
            v -= j*b;
            b /= 10;
        }
    }
    *pch++ = 0;
    return rb_cstr2inum(psz,10);
}

#to_r ⇒ Object

Converts a BigDecimal to a Rational.



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# File 'lib/bigdecimal/util.rb', line 44

def to_r 
   sign,digits,base,power = self.split
   numerator = sign*digits.to_i
   denomi_power = power - digits.size # base is always 10
   if denomi_power < 0
      Rational(numerator,base ** (-denomi_power))
   else
      Rational(numerator * (base ** denomi_power),1)
   end
end

#to_s(*args) ⇒ Object

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 fractional digits.

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.new(‘-123.45678901234567890’).to_s(‘5F’) -> ‘-123.45678 90123 45678 9’

BigDecimal.new(‘123.45678901234567890’).to_s(‘+8F’) -> ‘+123.45678901 23456789’

BigDecimal.new(‘123.45678901234567890’).to_s(‘ F’) -> ‘ 123.4567890123456789’



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# File 'bigdecimal.c', line 1487

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

    GUARD_OBJ(vp,GetVpValue(self,1));
    
    if(rb_scan_args(argc,argv,"01",&f)==1) {
        if(TYPE(f)==T_STRING) {
            SafeStringValue(f);
            psz = RSTRING_PTR(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 {
            mc  = GetPositiveInt(f);
        }
    }
    if(fmt) {
        nc = VpNumOfChars(vp,"F");
    } else {
        nc = VpNumOfChars(vp,"E");
    }
    if(mc>0) nc += (nc + mc - 1) / mc + 1;

    psz = ALLOCA_N(char,(unsigned int)nc);

    if(fmt) {
        VpToFString(vp, psz, mc, fPlus);
    } else {
        VpToString (vp, psz, mc, fPlus);
    }
    return rb_str_new2(psz);
}

#truncate(*args) ⇒ Object

truncate(n)

Truncate to the nearest 1, returning the result as a BigDecimal.

BigDecimal(‘3.14159’).truncate -> 3

BigDecimal(‘8.7’).truncate -> 8

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



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# File 'bigdecimal.c', line 1328

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

    if(rb_scan_args(argc,argv,"01",&vLoc)==0) {
        iLoc = 0;
    } else {
        Check_Type(vLoc, T_FIXNUM);
        iLoc = FIX2INT(vLoc);
    }

    GUARD_OBJ(a,GetVpValue(self,1));
    mx = a->Prec *(VpBaseFig() + 1);
    GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
    VpSetPrecLimit(pl);
    VpActiveRound(c,a,VP_ROUND_DOWN,iLoc); /* 0: truncate */
    return ToValue(c);
}

#zero? ⇒ Boolean

Returns True if the value is zero.

Returns:

  • (Boolean) 


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# File 'bigdecimal.c', line 747

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