# Class: BigDecimal

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

## Overview

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

## 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

Copyright (C) 2002 by Shigeo Kobayashi <[email protected]>.

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

Maintained by mrkn <[email protected]> and ruby-core members.

Documented by zzak <[email protected]>, mathew <[email protected]>, and many other contributors.

## Constant Summary collapse

VERSION =

The version of bigdecimal library

rb_str_new2(RUBY_BIGDECIMAL_VERSION)
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((SIGNED_VALUE)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 overflow (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.

0x10
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
INFINITY =

Positive infinity value.

f_BigDecimal(1, &arg, rb_cBigDecimal)
NAN =

'Not a Number' value.

f_BigDecimal(1, &arg, rb_cBigDecimal)

## Class Method Summary collapse

• Internal method used to provide marshalling support.

• BigDecimal.double_fig.

• BigDecimal.limit(digits).

• BigDecimal.mode(mode, value).

• Execute the provided block, but preserve the exception mode.

• Execute the provided block, but preserve the precision limit.

• Execute the provided block, but preserve the rounding mode.

## Instance Method Summary collapse

• %: a%b = a - (a.to_f/b).floor * b.

• call-seq: mult(value, digits).

• Returns the value raised to the power of n.

• Return self.

• a - b -> bigdecimal.

• Return the negation of self.

• For c = self/r: with round operation.

• a < b.

• a <= b.

• The comparison operator.

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

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

• a > b.

• a >= b.

• Method used to provide marshalling support.

• Returns the absolute value, as a BigDecimal.

• ceil(n).

• The coerce method provides support for Ruby type coercion.

• call-seq: div(value, digits) -> bigdecimal or integer.

• divmod(value).

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

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

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

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

• floor(n).

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

• Creates a hash for this BigDecimal.

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

• :nodoc:.

• Returns a string representation of self.

• %: a%b = a - (a.to_f/b).floor * b.

• call-seq: mult(value, digits).

• Returns True if the value is Not a Number.

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

• power(n) power(n, prec).

• Returns an Array of two Integer values.

• For c = self/r: with round operation.

• remainder.

• round(n, mode).

• Returns the sign of the value.

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

• sqrt(n).

• sub(value, digits) -> bigdecimal.

• call-seq: a.to_d -> bigdecimal.

• call-seq: a.to_digits -> string.

• Returns a new Float object having approximately the same value as the BigDecimal number.

• Returns the value as an Integer.

• Returns the value as an Integer.

• Converts a BigDecimal to a Rational.

• to_s(s).

• truncate(n).

• Returns True if the value is zero.

## Class Method Details

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

 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 # File 'bigdecimal.c', line 410 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)); 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.

 320 321 322 323 324 # File 'bigdecimal.c', line 320 static VALUE BigDecimal_double_fig(VALUE self) { return INT2FIX(VpDblFig()); }

### .interpret_loosely(str) ⇒ Object

 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 # File 'bigdecimal.c', line 2738 static VALUE BigDecimal_s_interpret_loosely(VALUE klass, VALUE str) { ENTER(1); char const *c_str; Real *pv; c_str = StringValueCStr(str); GUARD_OBJ(pv, VpAlloc(0, c_str, 0, 1)); pv->obj = TypedData_Wrap_Struct(klass, &BigDecimal_data_type, pv); RB_OBJ_FREEZE(pv->obj); return pv->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 less priority over any limit specified to instance methods such as ceil, floor, truncate, or round.

 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 # File 'bigdecimal.c', line 2764 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 (NIL_P(nFig)) return nCur; nf = NUM2INT(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, :up

round away from zero

ROUND_DOWN, :down, :truncate

round towards zero (truncate)

ROUND_HALF_UP, :half_up, :default

round towards the nearest neighbor, unless both neighbors are equidistant, in which case round away from zero. (default)

ROUND_HALF_DOWN, :half_down

round towards the nearest neighbor, unless both neighbors are equidistant, in which case round towards zero.

ROUND_HALF_EVEN, :half_even, :banker

round towards the nearest neighbor, unless both neighbors are equidistant, in which case round towards the even neighbor (Banker's rounding)

ROUND_CEILING, :ceiling, :ceil

round towards positive infinity (ceil)

ROUND_FLOOR, :floor

round towards negative infinity (floor)

 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 # File 'bigdecimal.c', line 558 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; }

### .save_exception_mode { ... } ⇒ Object

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

Yields:

 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 # File 'bigdecimal.c', line 2823 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; }

### .save_limit { ... } ⇒ Object

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

Yields:

 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 # File 'bigdecimal.c', line 2873 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; }

### .save_rounding_mode { ... } ⇒ Object

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

Yields:

 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 # File 'bigdecimal.c', line 2848 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 Method Details

### #% ⇒ Object

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

 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 # File 'bigdecimal.c', line 1429 static VALUE BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */ { ENTER(3); Real *div = NULL, *mod = NULL; if (BigDecimal_DoDivmod(self, r, &div, &mod)) { SAVE(div); SAVE(mod); return ToValue(mod); } return DoSomeOne(self, r, '%'); }

### #*(r) ⇒ Object

call-seq: 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.

 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 # File 'bigdecimal.c', line 1248 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, DBL_DIG+1, 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, VpCreateRbObject(mx *(VpBaseFig() + 1), "0")); VpMult(c, a, b); return ToValue(c); }

### #**(n) ⇒ Object

Returns the value raised to the power of n.

See BigDecimal#power.

 2535 2536 2537 2538 2539 # File 'bigdecimal.c', line 2535 static VALUE BigDecimal_power_op(VALUE self, VALUE exp) { return BigDecimal_power(1, &exp, self); }

### #+(r) ⇒ Object

e.g.

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.

 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 # File 'bigdecimal.c', line 927 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, DBL_DIG+1, 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,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

Return self.

+BigDecimal('5')  #=> 0.5e1
 904 905 906 907 908 # File 'bigdecimal.c', line 904 static VALUE BigDecimal_uplus(VALUE self) { return self; }

### #-(r) ⇒ Object

a - b -> bigdecimal

Subtract the specified value.

e.g.

c = a - b

The precision of the result value depends on the type of b.

If b is a Float, the precision of the result is Float::DIG+1.

If b is a BigDecimal, the precision of the result is b's precision of internal representation from platform. So, it's return value is platform dependent.

 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 # File 'bigdecimal.c', line 985 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, DBL_DIG+1, 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,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

Return the negation of self.

-BigDecimal('5')  #=> -0.5e1
 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 # File 'bigdecimal.c', line 1222 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

 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 # File 'bigdecimal.c', line 1317 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 (!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], (BDIGIT)(VpBaseVal() * (BDIGIT_DBL)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 ==, BigDecimal#coerce).

 1168 1169 1170 1171 1172 # File 'bigdecimal.c', line 1168 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 ==, BigDecimal#coerce).

 1181 1182 1183 1184 1185 # File 'bigdecimal.c', line 1181 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.

 1139 1140 1141 1142 1143 # File 'bigdecimal.c', line 1139 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('1.0') == 1.0  #=> true
 1155 1156 1157 1158 1159 # File 'bigdecimal.c', line 1155 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('1.0') == 1.0  #=> true
 1155 1156 1157 1158 1159 # File 'bigdecimal.c', line 1155 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 ==, BigDecimal#coerce).

 1194 1195 1196 1197 1198 # File 'bigdecimal.c', line 1194 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 ==, BigDecimal#coerce)

 1207 1208 1209 1210 1211 # File 'bigdecimal.c', line 1207 static VALUE BigDecimal_ge(VALUE self, VALUE r) { return BigDecimalCmp(self, r, 'G'); }

### #_dump ⇒ Object

Method used to provide marshalling support.

inf = BigDecimal('Infinity')
#=> Infinity
#=> Infinity

See the Marshal module.

 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 # File 'bigdecimal.c', line 388 static VALUE BigDecimal_dump(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *vp; char *psz; VALUE dummy; volatile VALUE dump; 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); sprintf(psz, "%"PRIuSIZE":", VpMaxPrec(vp)*VpBaseFig()); VpToString(vp, psz+strlen(psz), 0, 0); rb_str_resize(dump, strlen(psz)); return dump; }

### #abs ⇒ Object

Returns the absolute value, as a BigDecimal.

BigDecimal('5').abs  #=> 0.5e1
BigDecimal('-3').abs #=> 0.3e1
 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 # File 'bigdecimal.c', line 1698 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, VpCreateRbObject(mx, "0")); VpAsgn(c, a, 1); VpChangeSign(c, 1); return ToValue(c); }

e.g.

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.

 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 # File 'bigdecimal.c', line 1623 static VALUE BigDecimal_add2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = GetPrecisionInt(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 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

 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 # File 'bigdecimal.c', line 1953 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, VpCreateRbObject(mx, "0")); VpSetPrecLimit(pl); VpActiveRound(c, a, VP_ROUND_CEIL, iLoc); if (argc == 0) { return BigDecimal_to_i(ToValue(c)); } return ToValue(c); }

### #clone ⇒ Object

 2557 2558 2559 2560 2561 # File 'bigdecimal.c', line 2557 static VALUE BigDecimal_clone(VALUE self) { return self; }

### #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("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.

 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 # File 'bigdecimal.c', line 870 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, DBL_DIG+1, 1)); obj = rb_assoc_new(ToValue(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(*args) ⇒ Object

call-seq:

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.

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
 1613 1614 1615 1616 1617 1618 1619 1620 1621 # File 'bigdecimal.c', line 1613 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(r) ⇒ Object

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.

 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 # File 'bigdecimal.c', line 1527 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(ToValue(div), ToValue(mod)); } return DoSomeOne(self,r,rb_intern("divmod")); }

### #dup ⇒ Object

 2557 2558 2559 2560 2561 # File 'bigdecimal.c', line 2557 static VALUE BigDecimal_clone(VALUE self) { return self; }

### #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('1.0') == 1.0  #=> true

Returns:

• (Boolean)
 1155 1156 1157 1158 1159 # File 'bigdecimal.c', line 1155 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.

 2144 2145 2146 2147 2148 2149 # File 'bigdecimal.c', line 2144 static VALUE BigDecimal_exponent(VALUE self) { ssize_t e = VpExponent10(GetVpValue(self, 1)); return INT2NUM(e); }

### #finite? ⇒ Boolean

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

Returns:

• (Boolean)
 701 702 703 704 705 706 707 708 # File 'bigdecimal.c', line 701 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, as a BigDecimal.

 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 # File 'bigdecimal.c', line 1739 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, 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

 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 # File 'bigdecimal.c', line 1906 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, VpCreateRbObject(mx, "0")); 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(ToValue(c)); } return ToValue(c); }

### #frac ⇒ Object

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

 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 # File 'bigdecimal.c', line 1875 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, VpCreateRbObject(mx, "0")); VpFrac(c, a); return ToValue(c); }

### #hash ⇒ Object

Creates a hash for this BigDecimal.

Two BigDecimals with equal sign, fractional part and exponent have the same hash.

 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 # File 'bigdecimal.c', line 359 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(BDIGIT)*p->Prec); hash += p->exponent; } return ST2FIX(hash); }

### #infinite? ⇒ Boolean

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

Returns:

• (Boolean)
 691 692 693 694 695 696 697 698 # File 'bigdecimal.c', line 691 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; }

### #initialize_copy(other) ⇒ Object

:nodoc:

private method for dup and clone the provided BigDecimal other

 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 # File 'bigdecimal.c', line 2545 static VALUE BigDecimal_initialize_copy(VALUE self, VALUE other) { Real *pv = rb_check_typeddata(self, &BigDecimal_data_type); Real *x = rb_check_typeddata(other, &BigDecimal_data_type); if (self != other) { DATA_PTR(self) = VpCopy(pv, x); } return self; }

### #inspect ⇒ Object

Returns a string representation of self.

BigDecimal("1234.5678").inspect
#=> "0.12345678e4"
 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 # File 'bigdecimal.c', line 2156 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), 0, 0); rb_str_resize(str, strlen(RSTRING_PTR(str))); return str; }

### #modulo ⇒ Object

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

 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 # File 'bigdecimal.c', line 1429 static VALUE BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */ { ENTER(3); Real *div = NULL, *mod = NULL; if (BigDecimal_DoDivmod(self, r, &div, &mod)) { SAVE(div); SAVE(mod); return ToValue(mod); } return DoSomeOne(self, r, '%'); }

### #mult(b, n) ⇒ Object

call-seq: 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.

 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 # File 'bigdecimal.c', line 1671 static VALUE BigDecimal_mult2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = GetPrecisionInt(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 ToValue(cv); } }

### #nan? ⇒ Boolean

Returns True if the value is Not a Number.

Returns:

• (Boolean)
 680 681 682 683 684 685 686 # File 'bigdecimal.c', line 680 static VALUE BigDecimal_IsNaN(VALUE self) { Real *p = GetVpValue(self, 1); if (VpIsNaN(p)) return Qtrue; return Qfalse; }

### #nonzero? ⇒ Boolean

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

Returns:

• (Boolean)
 1129 1130 1131 1132 1133 1134 # File 'bigdecimal.c', line 1129 static VALUE BigDecimal_nonzero(VALUE self) { Real *a = GetVpValue(self, 1); return VpIsZero(a) ? Qnil : self; }

### #power(*args) ⇒ Object

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 **.

### #precs ⇒ Array

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.

BigDecimal('5').precs #=> [9, 18]

Returns:

• (Array)
 338 339 340 341 342 343 344 345 346 347 348 349 # File 'bigdecimal.c', line 338 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

 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 # File 'bigdecimal.c', line 1317 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 (!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], (BDIGIT)(VpBaseVal() * (BDIGIT_DBL)res->frac[0] / div->frac[0])); } return ToValue(c); }

### #remainder ⇒ Object

remainder

 1495 1496 1497 1498 1499 1500 1501 1502 1503 # File 'bigdecimal.c', line 1495 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 ToValue(rv); }

### #round(*args) ⇒ Object

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.

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.

 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 # File 'bigdecimal.c', line 1778 static VALUE BigDecimal_round(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *c, *a; int iLoc = 0; VALUE vLoc; VALUE vRound; size_t mx, pl; unsigned short sw = VpGetRoundMode(); switch (rb_scan_args(argc, argv, "02", &vLoc, &vRound)) { case 0: iLoc = 0; break; case 1: if (RB_TYPE_P(vLoc, T_HASH)) { sw = check_rounding_mode_option(vLoc); } else { iLoc = NUM2INT(vLoc); } 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, VpCreateRbObject(mx, "0")); VpSetPrecLimit(pl); VpActiveRound(c, a, sw, iLoc); if (argc == 0) { return BigDecimal_to_i(ToValue(c)); } 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

 2798 2799 2800 2801 2802 2803 # File 'bigdecimal.c', line 2798 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.)

 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 # File 'bigdecimal.c', line 2107 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); 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, INT2NUM(e)); return obj; }

### #sqrt(nFig) ⇒ Object

sqrt(n)

Returns the square root of the value.

Result has at least n significant digits.

 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 # File 'bigdecimal.c', line 1720 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 = GetPrecisionInt(nFig) + VpDblFig() + BASE_FIG; if (mx <= n) mx = n; GUARD_OBJ(c, VpCreateRbObject(mx, "0")); VpSqrt(c, a); return ToValue(c); }

### #sub(b, n) ⇒ Object

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.

 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 # File 'bigdecimal.c', line 1653 static VALUE BigDecimal_sub2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = GetPrecisionInt(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 ToValue(cv); } }

### #to_d ⇒ Object

call-seq:

a.to_d -> bigdecimal

Returns self.

require 'bigdecimal/util'

d = BigDecimal("3.14")
d.to_d                       # => 0.314e1
 106 107 108 # File 'lib/bigdecimal/util.rb', line 106 def to_d self end

### #to_digits ⇒ Object

call-seq:

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"
 86 87 88 89 90 91 92 93 94 # File 'lib/bigdecimal/util.rb', line 86 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 ⇒ 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.

 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 # File 'bigdecimal.c', line 777 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, 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 ⇒ Object

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.

 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 # File 'bigdecimal.c', line 730 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) * (BDIGIT_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 ⇒ Object

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.

 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 # File 'bigdecimal.c', line 730 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) * (BDIGIT_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_r ⇒ Object

Converts a BigDecimal to a Rational.

 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 # File 'bigdecimal.c', line 824 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(*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('-123.45678901234567890').to_s('5F')
#=> '-123.45678 90123 45678 9'

BigDecimal('123.45678901234567890').to_s('+8F')
#=> '+123.45678901 23456789'

BigDecimal('123.45678901234567890').to_s(' F')
#=> ' 123.4567890123456789'
 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 # File 'bigdecimal.c', line 2012 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_str_new(0, nc); psz = RSTRING_PTR(str); if (fmt) { VpToFString(vp, psz, mc, fPlus); } else { VpToString (vp, psz, mc, fPlus); } rb_str_resize(str, strlen(psz)); return str; }

### #truncate(*args) ⇒ Object

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

 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 # File 'bigdecimal.c', line 1846 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, VpCreateRbObject(mx, "0")); VpSetPrecLimit(pl); VpActiveRound(c, a, VP_ROUND_DOWN, iLoc); /* 0: truncate */ if (argc == 0) { return BigDecimal_to_i(ToValue(c)); } return ToValue(c); }

### #zero? ⇒ Boolean

Returns True if the value is zero.

Returns:

• (Boolean)
 1121 1122 1123 1124 1125 1126 # File 'bigdecimal.c', line 1121 static VALUE BigDecimal_zero(VALUE self) { Real *a = GetVpValue(self, 1); return VpIsZero(a) ? Qtrue : Qfalse; }