ruby/numeric.c

/**********************************************************************

  numeric.c -

  $Author$
  created at: Fri Aug 13 18:33:09 JST 1993

  Copyright (C) 1993-2007 Yukihiro Matsumoto

**********************************************************************/

#include "internal.h"
#include "ruby/util.h"
#include "id.h"
#include <ctype.h>
#include <math.h>
#include <stdio.h>

#if defined(__FreeBSD__) && __FreeBSD__ < 4
#include <floatingpoint.h>
#endif

#ifdef HAVE_FLOAT_H
#include <float.h>
#endif

#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

#if !defined HAVE_ISFINITE && !defined isfinite
#if defined HAVE_FINITE && !defined finite && !defined _WIN32
extern int finite(double);
# define HAVE_ISFINITE 1
# define isfinite(x) finite(x)
#endif
#endif

/* use IEEE 64bit values if not defined */
#ifndef FLT_RADIX
#define FLT_RADIX 2
#endif
#ifndef FLT_ROUNDS
#define FLT_ROUNDS 1
#endif
#ifndef DBL_MIN
#define DBL_MIN 2.2250738585072014e-308
#endif
#ifndef DBL_MAX
#define DBL_MAX 1.7976931348623157e+308
#endif
#ifndef DBL_MIN_EXP
#define DBL_MIN_EXP (-1021)
#endif
#ifndef DBL_MAX_EXP
#define DBL_MAX_EXP 1024
#endif
#ifndef DBL_MIN_10_EXP
#define DBL_MIN_10_EXP (-307)
#endif
#ifndef DBL_MAX_10_EXP
#define DBL_MAX_10_EXP 308
#endif
#ifndef DBL_DIG
#define DBL_DIG 15
#endif
#ifndef DBL_MANT_DIG
#define DBL_MANT_DIG 53
#endif
#ifndef DBL_EPSILON
#define DBL_EPSILON 2.2204460492503131e-16
#endif

#ifdef HAVE_INFINITY
#elif !defined(WORDS_BIGENDIAN) /* BYTE_ORDER == LITTLE_ENDIAN */
const union bytesequence4_or_float rb_infinity = {{0x00, 0x00, 0x80, 0x7f}};
#else
const union bytesequence4_or_float rb_infinity = {{0x7f, 0x80, 0x00, 0x00}};
#endif

#ifdef HAVE_NAN
#elif !defined(WORDS_BIGENDIAN) /* BYTE_ORDER == LITTLE_ENDIAN */
const union bytesequence4_or_float rb_nan = {{0x00, 0x00, 0xc0, 0x7f}};
#else
const union bytesequence4_or_float rb_nan = {{0x7f, 0xc0, 0x00, 0x00}};
#endif

#ifndef HAVE_ROUND
double
round(double x)
{
    double f;

    if (x > 0.0) {
	f = floor(x);
	x = f + (x - f >= 0.5);
    }
    else if (x < 0.0) {
	f = ceil(x);
	x = f - (f - x >= 0.5);
    }
    return x;
}
#endif

static VALUE fix_uminus(VALUE num);
static VALUE fix_mul(VALUE x, VALUE y);
static VALUE fix_lshift(long, unsigned long);
static VALUE fix_rshift(long, unsigned long);
static VALUE int_pow(long x, unsigned long y);
static VALUE int_cmp(VALUE x, VALUE y);
static int int_round_zero_p(VALUE num, int ndigits);
VALUE rb_int_floor(VALUE num, int ndigits);
VALUE rb_int_ceil(VALUE num, int ndigits);
static VALUE flo_to_i(VALUE num);
static int float_invariant_round(double number, int ndigits, VALUE *num);

static ID id_coerce, id_div, id_divmod;
#define id_to_i idTo_i
#define id_eq  idEq
#define id_cmp idCmp

VALUE rb_cNumeric;
VALUE rb_cFloat;
VALUE rb_cInteger;
VALUE rb_cFixnum;

VALUE rb_eZeroDivError;
VALUE rb_eFloatDomainError;

static ID id_to, id_by;

void
rb_num_zerodiv(void)
{
    rb_raise(rb_eZeroDivError, "divided by 0");
}

/* experimental API */
int
rb_num_to_uint(VALUE val, unsigned int *ret)
{
#define NUMERR_TYPE     1
#define NUMERR_NEGATIVE 2
#define NUMERR_TOOLARGE 3
    if (FIXNUM_P(val)) {
	long v = FIX2LONG(val);
#if SIZEOF_INT < SIZEOF_LONG
	if (v > (long)UINT_MAX) return NUMERR_TOOLARGE;
#endif
	if (v < 0) return NUMERR_NEGATIVE;
	*ret = (unsigned int)v;
	return 0;
    }

    if (RB_TYPE_P(val, T_BIGNUM)) {
	if (BIGNUM_NEGATIVE_P(val)) return NUMERR_NEGATIVE;
#if SIZEOF_INT < SIZEOF_LONG
	/* long is 64bit */
	return NUMERR_TOOLARGE;
#else
	/* long is 32bit */
	if (rb_absint_size(val, NULL) > sizeof(int)) return NUMERR_TOOLARGE;
	*ret = (unsigned int)rb_big2ulong((VALUE)val);
	return 0;
#endif
    }
    return NUMERR_TYPE;
}

#define method_basic_p(klass) rb_method_basic_definition_p(klass, mid)

static VALUE
compare_with_zero(VALUE num, ID mid)
{
    VALUE zero = INT2FIX(0);
    VALUE r = rb_check_funcall(num, mid, 1, &zero);
    if (r == Qundef) {
	rb_cmperr(num, zero);
    }
    return r;
}

#define FIXNUM_POSITIVE_P(num) ((SIGNED_VALUE)(num) > (SIGNED_VALUE)INT2FIX(0))
#define FIXNUM_NEGATIVE_P(num) ((SIGNED_VALUE)(num) < 0)
#define FIXNUM_ZERO_P(num) ((num) == INT2FIX(0))

#if 0
static inline int
int_pos_p(VALUE num)
{
    if (FIXNUM_P(num)) {
	return FIXNUM_POSITIVE_P(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return BIGNUM_POSITIVE_P(num);
    }
    return Qnil;
}
#endif

static inline int
int_neg_p(VALUE num)
{
    if (FIXNUM_P(num)) {
	return FIXNUM_NEGATIVE_P(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return BIGNUM_NEGATIVE_P(num);
    }
    return Qnil;
}

static inline int
positive_int_p(VALUE num)
{
    const ID mid = '>';

    if (FIXNUM_P(num)) {
	if (method_basic_p(rb_cFixnum))
	    return FIXNUM_POSITIVE_P(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	if (method_basic_p(rb_cBignum))
	    return BIGNUM_POSITIVE_P(num);
    }
    return RTEST(compare_with_zero(num, mid));
}

static inline int
negative_int_p(VALUE num)
{
    const ID mid = '<';

    if (FIXNUM_P(num)) {
	if (method_basic_p(rb_cFixnum))
	    return FIXNUM_NEGATIVE_P(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	if (method_basic_p(rb_cBignum))
	    return BIGNUM_NEGATIVE_P(num);
    }
    return RTEST(compare_with_zero(num, mid));
}

int
rb_num_negative_p(VALUE num)
{
    return negative_int_p(num);
}

/*
 *  call-seq:
 *     num.coerce(numeric)  ->  array
 *
 *  If a +numeric+ is the same type as +num+, returns an array containing
 *  +numeric+ and +num+. Otherwise, returns an array with both a +numeric+ and
 *  +num+ represented as Float objects.
 *
 *  This coercion mechanism is used by Ruby to handle mixed-type numeric
 *  operations: it is intended to find a compatible common type between the two
 *  operands of the operator.
 *
 *     1.coerce(2.5)   #=> [2.5, 1.0]
 *     1.2.coerce(3)   #=> [3.0, 1.2]
 *     1.coerce(2)     #=> [2, 1]
 */

static VALUE
num_coerce(VALUE x, VALUE y)
{
    if (CLASS_OF(x) == CLASS_OF(y))
	return rb_assoc_new(y, x);
    x = rb_Float(x);
    y = rb_Float(y);
    return rb_assoc_new(y, x);
}

static VALUE
coerce_body(VALUE arg)
{
    VALUE *x = (VALUE *)arg;
    return rb_funcall(x[1], id_coerce, 1, x[0]);
}

NORETURN(static void coerce_failed(VALUE x, VALUE y));
static void
coerce_failed(VALUE x, VALUE y)
{
    if (SPECIAL_CONST_P(y) || BUILTIN_TYPE(y) == T_FLOAT) {
	y = rb_inspect(y);
    }
    else {
	y = rb_obj_class(y);
    }
    rb_raise(rb_eTypeError, "%"PRIsVALUE" can't be coerced into %"PRIsVALUE,
	     y, rb_obj_class(x));
}

static VALUE
coerce_rescue(VALUE arg, VALUE errinfo)
{
    VALUE *x = (VALUE *)arg;
    coerce_failed(x[0], x[1]);
    return Qnil;		/* dummy */
}

static VALUE
coerce_rescue_quiet(VALUE arg, VALUE errinfo)
{
    return Qundef;
}

static int
do_coerce(VALUE *x, VALUE *y, int err)
{
    VALUE ary;
    VALUE a[2];

    a[0] = *x; a[1] = *y;

    if (!rb_respond_to(*y, id_coerce)) {
	if (err) {
	    coerce_failed(*x, *y);
	}
	return FALSE;
    }

    ary = rb_rescue(coerce_body, (VALUE)a, err ? coerce_rescue : coerce_rescue_quiet, (VALUE)a);
    if (ary == Qundef) {
	rb_warn("Numerical comparison operators will no more rescue exceptions of #coerce");
	rb_warn("in the next release. Return nil in #coerce if the coercion is impossible.");
	return FALSE;
    }
    if (!RB_TYPE_P(ary, T_ARRAY) || RARRAY_LEN(ary) != 2) {
	if (err) {
	    rb_raise(rb_eTypeError, "coerce must return [x, y]");
	}
	else if (!NIL_P(ary)) {
	    rb_warn("Bad return value for #coerce, called by numerical comparison operators.");
	    rb_warn("#coerce must return [x, y]. The next release will raise an error for this.");
	}
	return FALSE;
    }

    *x = RARRAY_AREF(ary, 0);
    *y = RARRAY_AREF(ary, 1);
    return TRUE;
}

VALUE
rb_num_coerce_bin(VALUE x, VALUE y, ID func)
{
    do_coerce(&x, &y, TRUE);
    return rb_funcall(x, func, 1, y);
}

VALUE
rb_num_coerce_cmp(VALUE x, VALUE y, ID func)
{
    if (do_coerce(&x, &y, FALSE))
	return rb_funcall(x, func, 1, y);
    return Qnil;
}

VALUE
rb_num_coerce_relop(VALUE x, VALUE y, ID func)
{
    VALUE c, x0 = x, y0 = y;

    if (!do_coerce(&x, &y, FALSE) ||
	NIL_P(c = rb_funcall(x, func, 1, y))) {
	rb_cmperr(x0, y0);
	return Qnil;		/* not reached */
    }
    return c;
}

/*
 * Trap attempts to add methods to Numeric objects. Always raises a TypeError.
 *
 * Numerics should be values; singleton_methods should not be added to them.
 */

static VALUE
num_sadded(VALUE x, VALUE name)
{
    ID mid = rb_to_id(name);
    /* ruby_frame = ruby_frame->prev; */ /* pop frame for "singleton_method_added" */
    rb_remove_method_id(rb_singleton_class(x), mid);
    rb_raise(rb_eTypeError,
	     "can't define singleton method \"%"PRIsVALUE"\" for %"PRIsVALUE,
	     rb_id2str(mid),
	     rb_obj_class(x));

    UNREACHABLE;
}

/*
 * Numerics are immutable values, which should not be copied.
 *
 * Any attempt to use this method on a Numeric will raise a TypeError.
 */
static VALUE
num_init_copy(VALUE x, VALUE y)
{
    rb_raise(rb_eTypeError, "can't copy %"PRIsVALUE, rb_obj_class(x));

    UNREACHABLE;
}

/*
 *  call-seq:
 *     +num  ->  num
 *
 *  Unary Plus---Returns the receiver's value.
 */

static VALUE
num_uplus(VALUE num)
{
    return num;
}

/*
 *  call-seq:
 *     num.i  ->  Complex(0,num)
 *
 *  Returns the corresponding imaginary number.
 *  Not available for complex numbers.
 */

static VALUE
num_imaginary(VALUE num)
{
    return rb_complex_new(INT2FIX(0), num);
}


/*
 *  call-seq:
 *     -num  ->  numeric
 *
 *  Unary Minus---Returns the receiver's value, negated.
 */

static VALUE
num_uminus(VALUE num)
{
    VALUE zero;

    zero = INT2FIX(0);
    do_coerce(&zero, &num, TRUE);

    return rb_funcall(zero, '-', 1, num);
}

/*
 *  call-seq:
 *     num.fdiv(numeric)  ->  float
 *
 *  Returns float division.
 */

static VALUE
num_fdiv(VALUE x, VALUE y)
{
    return rb_funcall(rb_Float(x), '/', 1, y);
}


/*
 *  call-seq:
 *     num.div(numeric)  ->  integer
 *
 *  Uses +/+ to perform division, then converts the result to an integer.
 *  +numeric+ does not define the +/+ operator; this is left to subclasses.
 *
 *  Equivalent to <code>num.divmod(numeric)[0]</code>.
 *
 *  See Numeric#divmod.
 */

static VALUE
num_div(VALUE x, VALUE y)
{
    if (rb_equal(INT2FIX(0), y)) rb_num_zerodiv();
    return rb_funcall(rb_funcall(x, '/', 1, y), rb_intern("floor"), 0);
}


/*
 *  call-seq:
 *     num.modulo(numeric)  ->  real
 *
 *     x.modulo(y) means x-y*(x/y).floor
 *
 *  Equivalent to <code>num.divmod(numeric)[1]</code>.
 *
 *  See Numeric#divmod.
 */

static VALUE
num_modulo(VALUE x, VALUE y)
{
    return rb_funcall(x, '-', 1,
		      rb_funcall(y, '*', 1,
				 rb_funcall(x, id_div, 1, y)));
}

/*
 *  call-seq:
 *     num.remainder(numeric)  ->  real
 *
 *     x.remainder(y) means x-y*(x/y).truncate
 *
 *  See Numeric#divmod.
 */

static VALUE
num_remainder(VALUE x, VALUE y)
{
    VALUE z = rb_funcall(x, '%', 1, y);

    if ((!rb_equal(z, INT2FIX(0))) &&
	((negative_int_p(x) &&
	  positive_int_p(y)) ||
	 (positive_int_p(x) &&
	  negative_int_p(y)))) {
	return rb_funcall(z, '-', 1, y);
    }
    return z;
}

/*
 *  call-seq:
 *     num.divmod(numeric)  ->  array
 *
 *  Returns an array containing the quotient and modulus obtained by dividing
 *  +num+ by +numeric+.
 *
 *  If <code>q, r = * x.divmod(y)</code>, then
 *
 *      q = floor(x/y)
 *      x = q*y+r
 *
 *  The quotient is rounded toward -infinity, as shown in the following table:
 *
 *     a    |  b  |  a.divmod(b)  |   a/b   | a.modulo(b) | a.remainder(b)
 *    ------+-----+---------------+---------+-------------+---------------
 *     13   |  4  |   3,    1     |   3     |    1        |     1
 *    ------+-----+---------------+---------+-------------+---------------
 *     13   | -4  |  -4,   -3     |  -4     |   -3        |     1
 *    ------+-----+---------------+---------+-------------+---------------
 *    -13   |  4  |  -4,    3     |  -4     |    3        |    -1
 *    ------+-----+---------------+---------+-------------+---------------
 *    -13   | -4  |   3,   -1     |   3     |   -1        |    -1
 *    ------+-----+---------------+---------+-------------+---------------
 *     11.5 |  4  |   2,    3.5   |   2.875 |    3.5      |     3.5
 *    ------+-----+---------------+---------+-------------+---------------
 *     11.5 | -4  |  -3,   -0.5   |  -2.875 |   -0.5      |     3.5
 *    ------+-----+---------------+---------+-------------+---------------
 *    -11.5 |  4  |  -3,    0.5   |  -2.875 |    0.5      |    -3.5
 *    ------+-----+---------------+---------+-------------+---------------
 *    -11.5 | -4  |   2,   -3.5   |   2.875 |   -3.5      |    -3.5
 *
 *
 *  Examples
 *
 *     11.divmod(3)         #=> [3, 2]
 *     11.divmod(-3)        #=> [-4, -1]
 *     11.divmod(3.5)       #=> [3, 0.5]
 *     (-11).divmod(3.5)    #=> [-4, 3.0]
 *     (11.5).divmod(3.5)   #=> [3, 1.0]
 */

static VALUE
num_divmod(VALUE x, VALUE y)
{
    return rb_assoc_new(num_div(x, y), num_modulo(x, y));
}

/*
 *  call-seq:
 *     num.real?  ->  true or false
 *
 *  Returns +true+ if +num+ is a Real number. (i.e. not Complex).
 */

static VALUE
num_real_p(VALUE num)
{
    return Qtrue;
}

/*
 *  call-seq:
 *     num.integer?  ->  true or false
 *
 *  Returns +true+ if +num+ is an Integer (including Fixnum and Bignum).
 *
 *      (1.0).integer? #=> false
 *      (1).integer?   #=> true
 */

static VALUE
num_int_p(VALUE num)
{
    return Qfalse;
}

/*
 *  call-seq:
 *     num.abs        ->  numeric
 *     num.magnitude  ->  numeric
 *
 *  Returns the absolute value of +num+.
 *
 *     12.abs         #=> 12
 *     (-34.56).abs   #=> 34.56
 *     -34.56.abs     #=> 34.56
 *
 *  Numeric#magnitude is an alias of Numeric#abs.
 */

static VALUE
num_abs(VALUE num)
{
    if (negative_int_p(num)) {
	return rb_funcall(num, idUMinus, 0);
    }
    return num;
}


/*
 *  call-seq:
 *     num.zero?  ->  true or false
 *
 *  Returns +true+ if +num+ has a zero value.
 */

static VALUE
num_zero_p(VALUE num)
{
    if (FIXNUM_P(num)) {
	if (FIX2LONG(num) == 0) {
	    return Qtrue;
	}
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_bigzero_p(num);
    }
    else if (rb_equal(num, INT2FIX(0))) {
	return Qtrue;
    }
    return Qfalse;
}


/*
 *  call-seq:
 *     num.nonzero?  ->  self or nil
 *
 *  Returns +self+ if +num+ is not zero, +nil+ otherwise.
 *
 *  This behavior is useful when chaining comparisons:
 *
 *     a = %w( z Bb bB bb BB a aA Aa AA A )
 *     b = a.sort {|a,b| (a.downcase <=> b.downcase).nonzero? || a <=> b }
 *     b   #=> ["A", "a", "AA", "Aa", "aA", "BB", "Bb", "bB", "bb", "z"]
 */

static VALUE
num_nonzero_p(VALUE num)
{
    if (RTEST(rb_funcallv(num, rb_intern("zero?"), 0, 0))) {
	return Qnil;
    }
    return num;
}

/*
 *  call-seq:
 *     num.to_int  ->  integer
 *
 *  Invokes the child class's +to_i+ method to convert +num+ to an integer.
 *
 *      1.0.class => Float
 *      1.0.to_int.class => Fixnum
 *      1.0.to_i.class => Fixnum
 */

static VALUE
num_to_int(VALUE num)
{
    return rb_funcallv(num, id_to_i, 0, 0);
}

/*
 *  call-seq:
 *     num.positive? ->  true or false
 *
 *  Returns +true+ if +num+ is greater than 0.
 */

static VALUE
num_positive_p(VALUE num)
{
    const ID mid = '>';

    if (FIXNUM_P(num)) {
	if (method_basic_p(rb_cFixnum))
	    return (SIGNED_VALUE)num > (SIGNED_VALUE)INT2FIX(0) ? Qtrue : Qfalse;
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	if (method_basic_p(rb_cBignum))
	    return BIGNUM_POSITIVE_P(num) && !rb_bigzero_p(num) ? Qtrue : Qfalse;
    }
    return compare_with_zero(num, mid);
}

/*
 *  call-seq:
 *     num.negative? ->  true or false
 *
 *  Returns +true+ if +num+ is less than 0.
 */

static VALUE
num_negative_p(VALUE num)
{
    return negative_int_p(num) ? Qtrue : Qfalse;
}


/********************************************************************
 *
 * Document-class: Float
 *
 *  Float objects represent inexact real numbers using the native
 *  architecture's double-precision floating point representation.
 *
 *  Floating point has a different arithmetic and is an inexact number.
 *  So you should know its esoteric system. see following:
 *
 *  - http://docs.sun.com/source/806-3568/ncg_goldberg.html
 *  - http://wiki.github.com/rdp/ruby_tutorials_core/ruby-talk-faq#wiki-floats_imprecise
 *  - http://en.wikipedia.org/wiki/Floating_point#Accuracy_problems
 */

VALUE
rb_float_new_in_heap(double d)
{
    NEWOBJ_OF(flt, struct RFloat, rb_cFloat, T_FLOAT | (RGENGC_WB_PROTECTED_FLOAT ? FL_WB_PROTECTED : 0));

    flt->float_value = d;
    OBJ_FREEZE(flt);
    return (VALUE)flt;
}

/*
 *  call-seq:
 *     float.to_s  ->  string
 *
 *  Returns a string containing a representation of self. As well as a fixed or
 *  exponential form of the +float+, the call may return +NaN+, +Infinity+, and
 *  +-Infinity+.
 */

static VALUE
flo_to_s(VALUE flt)
{
    enum {decimal_mant = DBL_MANT_DIG-DBL_DIG};
    enum {float_dig = DBL_DIG+1};
    char buf[float_dig + (decimal_mant + CHAR_BIT - 1) / CHAR_BIT + 10];
    double value = RFLOAT_VALUE(flt);
    VALUE s;
    char *p, *e;
    int sign, decpt, digs;

    if (isinf(value)) {
	static const char minf[] = "-Infinity";
	const int pos = (value > 0); /* skip "-" */
	return rb_usascii_str_new(minf+pos, strlen(minf)-pos);
    }
    else if (isnan(value))
	return rb_usascii_str_new2("NaN");

    p = ruby_dtoa(value, 0, 0, &decpt, &sign, &e);
    s = sign ? rb_usascii_str_new_cstr("-") : rb_usascii_str_new(0, 0);
    if ((digs = (int)(e - p)) >= (int)sizeof(buf)) digs = (int)sizeof(buf) - 1;
    memcpy(buf, p, digs);
    xfree(p);
    if (decpt > 0) {
	if (decpt < digs) {
	    memmove(buf + decpt + 1, buf + decpt, digs - decpt);
	    buf[decpt] = '.';
	    rb_str_cat(s, buf, digs + 1);
	}
	else if (decpt <= DBL_DIG) {
	    long len;
	    char *ptr;
	    rb_str_cat(s, buf, digs);
	    rb_str_resize(s, (len = RSTRING_LEN(s)) + decpt - digs + 2);
	    ptr = RSTRING_PTR(s) + len;
	    if (decpt > digs) {
		memset(ptr, '0', decpt - digs);
		ptr += decpt - digs;
	    }
	    memcpy(ptr, ".0", 2);
	}
	else {
	    goto exp;
	}
    }
    else if (decpt > -4) {
	long len;
	char *ptr;
	rb_str_cat(s, "0.", 2);
	rb_str_resize(s, (len = RSTRING_LEN(s)) - decpt + digs);
	ptr = RSTRING_PTR(s);
	memset(ptr += len, '0', -decpt);
	memcpy(ptr -= decpt, buf, digs);
    }
    else {
      exp:
	if (digs > 1) {
	    memmove(buf + 2, buf + 1, digs - 1);
	}
	else {
	    buf[2] = '0';
	    digs++;
	}
	buf[1] = '.';
	rb_str_cat(s, buf, digs + 1);
	rb_str_catf(s, "e%+03d", decpt - 1);
    }
    return s;
}

/*
 *  call-seq:
 *     float.coerce(numeric)  ->  array
 *
 *  Returns an array with both a +numeric+ and a +float+ represented as Float
 *  objects.
 *
 *  This is achieved by converting a +numeric+ to a Float.
 *
 *     1.2.coerce(3)       #=> [3.0, 1.2]
 *     2.5.coerce(1.1)     #=> [1.1, 2.5]
 */

static VALUE
flo_coerce(VALUE x, VALUE y)
{
    return rb_assoc_new(rb_Float(y), x);
}

/*
 * call-seq:
 *    -float  ->  float
 *
 * Returns float, negated.
 */

static VALUE
flo_uminus(VALUE flt)
{
    return DBL2NUM(-RFLOAT_VALUE(flt));
}

/*
 * call-seq:
 *   float + other  ->  float
 *
 * Returns a new float which is the sum of +float+ and +other+.
 */

static VALUE
flo_plus(VALUE x, VALUE y)
{
    if (RB_TYPE_P(y, T_FIXNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) + (double)FIX2LONG(y));
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) + rb_big2dbl(y));
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM(RFLOAT_VALUE(x) + RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, '+');
    }
}

/*
 * call-seq:
 *   float - other  ->  float
 *
 * Returns a new float which is the difference of +float+ and +other+.
 */

static VALUE
flo_minus(VALUE x, VALUE y)
{
    if (RB_TYPE_P(y, T_FIXNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) - (double)FIX2LONG(y));
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) - rb_big2dbl(y));
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM(RFLOAT_VALUE(x) - RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, '-');
    }
}

/*
 * call-seq:
 *   float * other  ->  float
 *
 * Returns a new float which is the product of +float+ and +other+.
 */

static VALUE
flo_mul(VALUE x, VALUE y)
{
    if (RB_TYPE_P(y, T_FIXNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) * (double)FIX2LONG(y));
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return DBL2NUM(RFLOAT_VALUE(x) * rb_big2dbl(y));
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM(RFLOAT_VALUE(x) * RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, '*');
    }
}

/*
 * call-seq:
 *   float / other  ->  float
 *
 * Returns a new float which is the result of dividing +float+ by +other+.
 */

static VALUE
flo_div(VALUE x, VALUE y)
{
    long f_y;
    double d;

    if (RB_TYPE_P(y, T_FIXNUM)) {
	f_y = FIX2LONG(y);
	return DBL2NUM(RFLOAT_VALUE(x) / (double)f_y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	d = rb_big2dbl(y);
	return DBL2NUM(RFLOAT_VALUE(x) / d);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM(RFLOAT_VALUE(x) / RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, '/');
    }
}

/*
 *  call-seq:
 *     float.fdiv(numeric)  ->  float
 *     float.quo(numeric)  ->  float
 *
 *  Returns <code>float / numeric</code>, same as Float#/.
 */

static VALUE
flo_quo(VALUE x, VALUE y)
{
    return rb_funcall(x, '/', 1, y);
}

static void
flodivmod(double x, double y, double *divp, double *modp)
{
    double div, mod;

    if (isnan(y)) {
	/* y is NaN so all results are NaN */
	if (modp) *modp = y;
	if (divp) *divp = y;
	return;
    }
    if (y == 0.0) rb_num_zerodiv();
    if ((x == 0.0) || (isinf(y) && !isinf(x)))
        mod = x;
    else {
#ifdef HAVE_FMOD
	mod = fmod(x, y);
#else
	double z;

	modf(x/y, &z);
	mod = x - z * y;
#endif
    }
    if (isinf(x) && !isinf(y))
	div = x;
    else {
	div = (x - mod) / y;
	if (modp && divp) div = round(div);
    }
    if (y*mod < 0) {
	mod += y;
	div -= 1.0;
    }
    if (modp) *modp = mod;
    if (divp) *divp = div;
}

/*
 * Returns the modulo of division of x by y.
 * An error will be raised if y == 0.
 */

double
ruby_float_mod(double x, double y)
{
    double mod;
    flodivmod(x, y, 0, &mod);
    return mod;
}


/*
 *  call-seq:
 *     float % other        ->  float
 *     float.modulo(other)  ->  float
 *
 *  Return the modulo after division of +float+ by +other+.
 *
 *     6543.21.modulo(137)      #=> 104.21
 *     6543.21.modulo(137.24)   #=> 92.9299999999996
 */

static VALUE
flo_mod(VALUE x, VALUE y)
{
    double fy;

    if (RB_TYPE_P(y, T_FIXNUM)) {
	fy = (double)FIX2LONG(y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	fy = rb_big2dbl(y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	fy = RFLOAT_VALUE(y);
    }
    else {
	return rb_num_coerce_bin(x, y, '%');
    }
    return DBL2NUM(ruby_float_mod(RFLOAT_VALUE(x), fy));
}

static VALUE
dbl2ival(double d)
{
    if (FIXABLE(d)) {
	return LONG2FIX((long)d);
    }
    return rb_dbl2big(d);
}

/*
 *  call-seq:
 *     float.divmod(numeric)  ->  array
 *
 *  See Numeric#divmod.
 *
 *      42.0.divmod 6 #=> [7, 0.0]
 *      42.0.divmod 5 #=> [8, 2.0]
 */

static VALUE
flo_divmod(VALUE x, VALUE y)
{
    double fy, div, mod;
    volatile VALUE a, b;

    if (RB_TYPE_P(y, T_FIXNUM)) {
	fy = (double)FIX2LONG(y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	fy = rb_big2dbl(y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	fy = RFLOAT_VALUE(y);
    }
    else {
	return rb_num_coerce_bin(x, y, id_divmod);
    }
    flodivmod(RFLOAT_VALUE(x), fy, &div, &mod);
    a = dbl2ival(div);
    b = DBL2NUM(mod);
    return rb_assoc_new(a, b);
}

/*
 * call-seq:
 *
 *  float ** other  ->  float
 *
 * Raises +float+ to the power of +other+.
 *
 *    2.0**3      #=> 8.0
 */

static VALUE
flo_pow(VALUE x, VALUE y)
{
    double dx, dy;
    if (RB_TYPE_P(y, T_FIXNUM)) {
	dx = RFLOAT_VALUE(x);
	dy = (double)FIX2LONG(y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	dx = RFLOAT_VALUE(x);
	dy = rb_big2dbl(y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	dx = RFLOAT_VALUE(x);
	dy = RFLOAT_VALUE(y);
	if (dx < 0 && dy != round(dy))
	    return rb_funcall(rb_complex_raw1(x), idPow, 1, y);
    }
    else {
	return rb_num_coerce_bin(x, y, idPow);
    }
    return DBL2NUM(pow(dx, dy));
}

/*
 *  call-seq:
 *     num.eql?(numeric)  ->  true or false
 *
 *  Returns +true+ if +num+ and +numeric+ are the same type and have equal
 *  values.  Contrast this with <code>Numeric#==</code>, which performs
 *  type conversions.
 *
 *     1 == 1.0          #=> true
 *     1.eql?(1.0)       #=> false
 *     (1.0).eql?(1.0)   #=> true
 *     68719476736.eql?(68719476736.0)   #=> false
 */

static VALUE
num_eql(VALUE x, VALUE y)
{
    if (TYPE(x) != TYPE(y)) return Qfalse;

    if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_eql(x, y);
    }

    return rb_equal(x, y);
}

/*
 *  call-seq:
 *     number <=> other  ->  0 or nil
 *
 *  Returns zero if +number+ equals +other+, otherwise +nil+ is returned if the
 *  two values are incomparable.
 */

static VALUE
num_cmp(VALUE x, VALUE y)
{
    if (x == y) return INT2FIX(0);
    return Qnil;
}

static VALUE
num_equal(VALUE x, VALUE y)
{
    if (x == y) return Qtrue;
    return rb_funcall(y, id_eq, 1, x);
}

/*
 *  call-seq:
 *     float == obj  ->  true or false
 *
 *  Returns +true+ only if +obj+ has the same value as +float+. Contrast this
 *  with Float#eql?, which requires obj to be a Float.
 *
 *  The result of <code>NaN == NaN</code> is undefined, so the
 *  implementation-dependent value is returned.
 *
 *     1.0 == 1   #=> true
 *
 */

static VALUE
flo_eq(VALUE x, VALUE y)
{
    volatile double a, b;

    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        return rb_integer_float_eq(y, x);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(b)) return Qfalse;
#endif
    }
    else {
	return num_equal(x, y);
    }
    a = RFLOAT_VALUE(x);
#if defined(_MSC_VER) && _MSC_VER < 1300
    if (isnan(a)) return Qfalse;
#endif
    return (a == b)?Qtrue:Qfalse;
}

/*
 * call-seq:
 *   float.hash  ->  integer
 *
 * Returns a hash code for this float.
 *
 * See also Object#hash.
 */

static VALUE
flo_hash(VALUE num)
{
    return rb_dbl_hash(RFLOAT_VALUE(num));
}

VALUE
rb_dbl_hash(double d)
{
    st_index_t hash;

    /* normalize -0.0 to 0.0 */
    if (d == 0.0) d = 0.0;
    hash = rb_memhash(&d, sizeof(d));
    return LONG2FIX(hash);
}

VALUE
rb_dbl_cmp(double a, double b)
{
    if (isnan(a) || isnan(b)) return Qnil;
    if (a == b) return INT2FIX(0);
    if (a > b) return INT2FIX(1);
    if (a < b) return INT2FIX(-1);
    return Qnil;
}

/*
 *  call-seq:
 *     float <=> real  ->  -1, 0, +1 or nil
 *
 *  Returns -1, 0, +1 or nil depending on whether +float+ is less than, equal
 *  to, or greater than +real+. This is the basis for the tests in Comparable.
 *
 *  The result of <code>NaN <=> NaN</code> is undefined, so the
 *  implementation-dependent value is returned.
 *
 *  +nil+ is returned if the two values are incomparable.
 */

static VALUE
flo_cmp(VALUE x, VALUE y)
{
    double a, b;
    VALUE i;

    a = RFLOAT_VALUE(x);
    if (isnan(a)) return Qnil;
    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return INT2FIX(-FIX2INT(rel));
        return rel;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
    }
    else {
	if (isinf(a) && (i = rb_check_funcall(y, rb_intern("infinite?"), 0, 0)) != Qundef) {
	    if (RTEST(i)) {
		int j = rb_cmpint(i, x, y);
		j = (a > 0.0) ? (j > 0 ? 0 : +1) : (j < 0 ? 0 : -1);
		return INT2FIX(j);
	    }
	    if (a > 0.0) return INT2FIX(1);
	    return INT2FIX(-1);
	}
	return rb_num_coerce_cmp(x, y, id_cmp);
    }
    return rb_dbl_cmp(a, b);
}

/*
 * call-seq:
 *   float > real  ->  true or false
 *
 * Returns +true+ if +float+ is greater than +real+.
 *
 * The result of <code>NaN > NaN</code> is undefined, so the
 * implementation-dependent value is returned.
 */

static VALUE
flo_gt(VALUE x, VALUE y)
{
    double a, b;

    a = RFLOAT_VALUE(x);
    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return -FIX2INT(rel) > 0 ? Qtrue : Qfalse;
        return Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(b)) return Qfalse;
#endif
    }
    else {
	return rb_num_coerce_relop(x, y, '>');
    }
#if defined(_MSC_VER) && _MSC_VER < 1300
    if (isnan(a)) return Qfalse;
#endif
    return (a > b)?Qtrue:Qfalse;
}

/*
 * call-seq:
 *   float >= real  ->  true or false
 *
 * Returns +true+ if +float+ is greater than or equal to +real+.
 *
 * The result of <code>NaN >= NaN</code> is undefined, so the
 * implementation-dependent value is returned.
 */

static VALUE
flo_ge(VALUE x, VALUE y)
{
    double a, b;

    a = RFLOAT_VALUE(x);
    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return -FIX2INT(rel) >= 0 ? Qtrue : Qfalse;
        return Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(b)) return Qfalse;
#endif
    }
    else {
	return rb_num_coerce_relop(x, y, idGE);
    }
#if defined(_MSC_VER) && _MSC_VER < 1300
    if (isnan(a)) return Qfalse;
#endif
    return (a >= b)?Qtrue:Qfalse;
}

/*
 * call-seq:
 *   float < real  ->  true or false
 *
 * Returns +true+ if +float+ is less than +real+.
 *
 * The result of <code>NaN < NaN</code> is undefined, so the
 * implementation-dependent value is returned.
 */

static VALUE
flo_lt(VALUE x, VALUE y)
{
    double a, b;

    a = RFLOAT_VALUE(x);
    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return -FIX2INT(rel) < 0 ? Qtrue : Qfalse;
        return Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(b)) return Qfalse;
#endif
    }
    else {
	return rb_num_coerce_relop(x, y, '<');
    }
#if defined(_MSC_VER) && _MSC_VER < 1300
    if (isnan(a)) return Qfalse;
#endif
    return (a < b)?Qtrue:Qfalse;
}

/*
 * call-seq:
 *   float <= real  ->  true or false
 *
 * Returns +true+ if +float+ is less than or equal to +real+.
 *
 * The result of <code>NaN <= NaN</code> is undefined, so the
 * implementation-dependent value is returned.
 */

static VALUE
flo_le(VALUE x, VALUE y)
{
    double a, b;

    a = RFLOAT_VALUE(x);
    if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
        VALUE rel = rb_integer_float_cmp(y, x);
        if (FIXNUM_P(rel))
            return -FIX2INT(rel) <= 0 ? Qtrue : Qfalse;
        return Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(b)) return Qfalse;
#endif
    }
    else {
	return rb_num_coerce_relop(x, y, idLE);
    }
#if defined(_MSC_VER) && _MSC_VER < 1300
    if (isnan(a)) return Qfalse;
#endif
    return (a <= b)?Qtrue:Qfalse;
}

/*
 *  call-seq:
 *     float.eql?(obj)  ->  true or false
 *
 *  Returns +true+ only if +obj+ is a Float with the same value as +float+.
 *  Contrast this with Float#==, which performs type conversions.
 *
 *  The result of <code>NaN.eql?(NaN)</code> is undefined, so the
 *  implementation-dependent value is returned.
 *
 *     1.0.eql?(1)   #=> false
 */

static VALUE
flo_eql(VALUE x, VALUE y)
{
    if (RB_TYPE_P(y, T_FLOAT)) {
	double a = RFLOAT_VALUE(x);
	double b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
	if (isnan(a) || isnan(b)) return Qfalse;
#endif
	if (a == b)
	    return Qtrue;
    }
    return Qfalse;
}

/*
 * call-seq:
 *   float.to_f  ->  self
 *
 * Since +float+ is already a float, returns +self+.
 */

static VALUE
flo_to_f(VALUE num)
{
    return num;
}

/*
 *  call-seq:
 *     float.abs        ->  float
 *     float.magnitude  ->  float
 *
 *  Returns the absolute value of +float+.
 *
 *     (-34.56).abs   #=> 34.56
 *     -34.56.abs     #=> 34.56
 *
 */

static VALUE
flo_abs(VALUE flt)
{
    double val = fabs(RFLOAT_VALUE(flt));
    return DBL2NUM(val);
}

/*
 *  call-seq:
 *     float.zero?  ->  true or false
 *
 *  Returns +true+ if +float+ is 0.0.
 *
 */

static VALUE
flo_zero_p(VALUE num)
{
    if (RFLOAT_VALUE(num) == 0.0) {
	return Qtrue;
    }
    return Qfalse;
}

/*
 *  call-seq:
 *     float.nan?  ->  true or false
 *
 *  Returns +true+ if +float+ is an invalid IEEE floating point number.
 *
 *     a = -1.0      #=> -1.0
 *     a.nan?        #=> false
 *     a = 0.0/0.0   #=> NaN
 *     a.nan?        #=> true
 */

static VALUE
flo_is_nan_p(VALUE num)
{
    double value = RFLOAT_VALUE(num);

    return isnan(value) ? Qtrue : Qfalse;
}

/*
 *  call-seq:
 *     float.infinite?  ->  nil, -1, +1
 *
 *  Return values corresponding to the value of +float+:
 *
 *  +finite+::	    +nil+
 *  +-Infinity+::   +-1+
 *  ++Infinity+::   +1+
 *
 *  For example:
 *
 *     (0.0).infinite?        #=> nil
 *     (-1.0/0.0).infinite?   #=> -1
 *     (+1.0/0.0).infinite?   #=> 1
 */

static VALUE
flo_is_infinite_p(VALUE num)
{
    double value = RFLOAT_VALUE(num);

    if (isinf(value)) {
	return INT2FIX( value < 0 ? -1 : 1 );
    }

    return Qnil;
}

/*
 *  call-seq:
 *     float.finite?  ->  true or false
 *
 *  Returns +true+ if +float+ is a valid IEEE floating point number (it is not
 *  infinite, and Float#nan? is +false+).
 *
 */

static VALUE
flo_is_finite_p(VALUE num)
{
    double value = RFLOAT_VALUE(num);

#ifdef HAVE_ISFINITE
    if (!isfinite(value))
	return Qfalse;
#else
    if (isinf(value) || isnan(value))
	return Qfalse;
#endif

    return Qtrue;
}

/*
 *  call-seq:
 *     float.next_float  ->  float
 *
 *  Returns the next representable floating-point number.
 *
 *  Float::MAX.next_float and Float::INFINITY.next_float is Float::INFINITY.
 *
 *  Float::NAN.next_float is Float::NAN.
 *
 *  For example:
 *
 *    p 0.01.next_float  #=> 0.010000000000000002
 *    p 1.0.next_float   #=> 1.0000000000000002
 *    p 100.0.next_float #=> 100.00000000000001
 *
 *    p 0.01.next_float - 0.01   #=> 1.734723475976807e-18
 *    p 1.0.next_float - 1.0     #=> 2.220446049250313e-16
 *    p 100.0.next_float - 100.0 #=> 1.4210854715202004e-14
 *
 *    f = 0.01; 20.times { printf "%-20a %s\n", f, f.to_s; f = f.next_float }
 *    #=> 0x1.47ae147ae147bp-7 0.01
 *    #   0x1.47ae147ae147cp-7 0.010000000000000002
 *    #   0x1.47ae147ae147dp-7 0.010000000000000004
 *    #   0x1.47ae147ae147ep-7 0.010000000000000005
 *    #   0x1.47ae147ae147fp-7 0.010000000000000007
 *    #   0x1.47ae147ae148p-7  0.010000000000000009
 *    #   0x1.47ae147ae1481p-7 0.01000000000000001
 *    #   0x1.47ae147ae1482p-7 0.010000000000000012
 *    #   0x1.47ae147ae1483p-7 0.010000000000000014
 *    #   0x1.47ae147ae1484p-7 0.010000000000000016
 *    #   0x1.47ae147ae1485p-7 0.010000000000000018
 *    #   0x1.47ae147ae1486p-7 0.01000000000000002
 *    #   0x1.47ae147ae1487p-7 0.010000000000000021
 *    #   0x1.47ae147ae1488p-7 0.010000000000000023
 *    #   0x1.47ae147ae1489p-7 0.010000000000000024
 *    #   0x1.47ae147ae148ap-7 0.010000000000000026
 *    #   0x1.47ae147ae148bp-7 0.010000000000000028
 *    #   0x1.47ae147ae148cp-7 0.01000000000000003
 *    #   0x1.47ae147ae148dp-7 0.010000000000000031
 *    #   0x1.47ae147ae148ep-7 0.010000000000000033
 *
 *    f = 0.0
 *    100.times { f += 0.1 }
 *    p f                            #=> 9.99999999999998       # should be 10.0 in the ideal world.
 *    p 10-f                         #=> 1.9539925233402755e-14 # the floating-point error.
 *    p(10.0.next_float-10)          #=> 1.7763568394002505e-15 # 1 ulp (units in the last place).
 *    p((10-f)/(10.0.next_float-10)) #=> 11.0                   # the error is 11 ulp.
 *    p((10-f)/(10*Float::EPSILON))  #=> 8.8                    # approximation of the above.
 *    p "%a" % f                     #=> "0x1.3fffffffffff5p+3" # the last hex digit is 5.  16 - 5 = 11 ulp.
 *
 */
static VALUE
flo_next_float(VALUE vx)
{
    double x, y;
    x = NUM2DBL(vx);
    y = nextafter(x, INFINITY);
    return DBL2NUM(y);
}

/*
 *  call-seq:
 *     float.prev_float  ->  float
 *
 *  Returns the previous representable floating-point number.
 *
 *  (-Float::MAX).prev_float and (-Float::INFINITY).prev_float is -Float::INFINITY.
 *
 *  Float::NAN.prev_float is Float::NAN.
 *
 *  For example:
 *
 *    p 0.01.prev_float  #=> 0.009999999999999998
 *    p 1.0.prev_float   #=> 0.9999999999999999
 *    p 100.0.prev_float #=> 99.99999999999999
 *
 *    p 0.01 - 0.01.prev_float   #=> 1.734723475976807e-18
 *    p 1.0 - 1.0.prev_float     #=> 1.1102230246251565e-16
 *    p 100.0 - 100.0.prev_float #=> 1.4210854715202004e-14
 *
 *    f = 0.01; 20.times { printf "%-20a %s\n", f, f.to_s; f = f.prev_float }
 *    #=> 0x1.47ae147ae147bp-7 0.01
 *    #   0x1.47ae147ae147ap-7 0.009999999999999998
 *    #   0x1.47ae147ae1479p-7 0.009999999999999997
 *    #   0x1.47ae147ae1478p-7 0.009999999999999995
 *    #   0x1.47ae147ae1477p-7 0.009999999999999993
 *    #   0x1.47ae147ae1476p-7 0.009999999999999992
 *    #   0x1.47ae147ae1475p-7 0.00999999999999999
 *    #   0x1.47ae147ae1474p-7 0.009999999999999988
 *    #   0x1.47ae147ae1473p-7 0.009999999999999986
 *    #   0x1.47ae147ae1472p-7 0.009999999999999985
 *    #   0x1.47ae147ae1471p-7 0.009999999999999983
 *    #   0x1.47ae147ae147p-7  0.009999999999999981
 *    #   0x1.47ae147ae146fp-7 0.00999999999999998
 *    #   0x1.47ae147ae146ep-7 0.009999999999999978
 *    #   0x1.47ae147ae146dp-7 0.009999999999999976
 *    #   0x1.47ae147ae146cp-7 0.009999999999999974
 *    #   0x1.47ae147ae146bp-7 0.009999999999999972
 *    #   0x1.47ae147ae146ap-7 0.00999999999999997
 *    #   0x1.47ae147ae1469p-7 0.009999999999999969
 *    #   0x1.47ae147ae1468p-7 0.009999999999999967
 *
 */
static VALUE
flo_prev_float(VALUE vx)
{
    double x, y;
    x = NUM2DBL(vx);
    y = nextafter(x, -INFINITY);
    return DBL2NUM(y);
}

/*
 *  call-seq:
 *     float.floor([ndigits])  ->  integer or float
 *
 *  Returns the largest number less than or equal to +float+ in
 *  decimal digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and floor down for negative.
 *
 *     1.2.floor      #=> 1
 *     2.0.floor      #=> 2
 *     (-1.2).floor   #=> -2
 *     (-2.0).floor   #=> -2
 *
 *     1.234567.floor(2)  #=> 1.23
 *     1.234567.floor(3)  #=> 1.234
 *     1.234567.floor(4)  #=> 1.2345
 *     1.234567.floor(5)  #=> 1.23456
 *
 *     34567.89.floor(-5) #=> 0
 *     34567.89.floor(-4) #=> 30000
 *     34567.89.floor(-3) #=> 34000
 *     34567.89.floor(-2) #=> 34500
 *     34567.89.floor(-1) #=> 34560
 *     34567.89.floor(0)  #=> 34567
 *     34567.89.floor(1)  #=> 34567.8
 *     34567.89.floor(2)  #=> 34567.89
 *     34567.89.floor(3)  #=> 34567.89
 */

static VALUE
flo_floor(int argc, VALUE *argv, VALUE num)
{
    double number, f;
    long val;
    int ndigits = 0;

    if (rb_check_arity(argc, 0, 1)) {
	ndigits = NUM2INT(argv[0]);
    }
    if (ndigits < 0) {
	return rb_int_floor(flo_to_i(num), ndigits);
    }
    number = RFLOAT_VALUE(num);
    if (ndigits > 0) {
	if (float_invariant_round(number, ndigits, &num)) return num;
	f = pow(10, ndigits);
	f = floor(number * f) / f;
	return DBL2NUM(f);
    }
    f = floor(number);
    if (!FIXABLE(f)) {
	return rb_dbl2big(f);
    }
    val = (long)f;
    return LONG2FIX(val);
}

/*
 *  call-seq:
 *     float.ceil([ndigits])  ->  integer or float
 *
 *  Returns the smallest number greater than or equal to +float+ in decimal
 *  digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and ceil up for negative.
 *
 *     1.2.ceil      #=> 2
 *     2.0.ceil      #=> 2
 *     (-1.2).ceil   #=> -1
 *     (-2.0).ceil   #=> -2
 *     1.234567.ceil(2)  #=> 1.24
 *     1.234567.ceil(3)  #=> 1.235
 *     1.234567.ceil(4)  #=> 1.2346
 *     1.234567.ceil(5)  #=> 1.23457
 *
 *     34567.89.ceil(-5) #=> 100000
 *     34567.89.ceil(-4) #=> 40000
 *     34567.89.ceil(-3) #=> 35000
 *     34567.89.ceil(-2) #=> 34600
 *     34567.89.ceil(-1) #=> 34570
 *     34567.89.ceil(0)  #=> 34568
 *     34567.89.ceil(1)  #=> 34567.9
 *     34567.89.ceil(2)  #=> 34567.89
 *     34567.89.ceil(3)  #=> 34567.89
 */

static VALUE
flo_ceil(int argc, VALUE *argv, VALUE num)
{
    double number, f;
    int ndigits = 0;

    if (rb_check_arity(argc, 0, 1)) {
       ndigits = NUM2INT(argv[0]);
    }
    number = RFLOAT_VALUE(num);
    if (ndigits < 0) {
	return rb_int_ceil(dbl2ival(ceil(number)), ndigits);
    }
    if (ndigits == 0) {
	return dbl2ival(ceil(number));
    }
    if (float_invariant_round(number, ndigits, &num)) return num;
    f = pow(10, ndigits);
    return DBL2NUM(ceil(number * f) / f);
}

static int
int_round_zero_p(VALUE num, int ndigits)
{
    long bytes;
    /* If 10**N / 2 > num, then return 0 */
    /* We have log_256(10) > 0.415241 and log_256(1/2) = -0.125, so */
    if (FIXNUM_P(num)) {
	bytes = sizeof(long);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	bytes = rb_big_size(num);
    }
    else {
	bytes = NUM2LONG(rb_funcall(num, idSize, 0));
    }
    return (-0.415241 * ndigits - 0.125 > bytes);
}

/*
 * Assumes num is an Integer, ndigits <= 0
 */
VALUE
rb_int_round(VALUE num, int ndigits)
{
    VALUE n, f, h, r;

    if (int_round_zero_p(num, ndigits)) {
	return INT2FIX(0);
    }

    f = int_pow(10, -ndigits);
    if (FIXNUM_P(num) && FIXNUM_P(f)) {
	SIGNED_VALUE x = FIX2LONG(num), y = FIX2LONG(f);
	int neg = x < 0;
	if (neg) x = -x;
	x = (x + y / 2) / y * y;
	if (neg) x = -x;
	return LONG2NUM(x);
    }
    if (RB_TYPE_P(f, T_FLOAT)) {
	/* then int_pow overflow */
	return INT2FIX(0);
    }
    h = rb_int_idiv(f, INT2FIX(2));
    r = rb_int_modulo(num, f);
    n = rb_int_minus(num, r);
    r = int_cmp(r, h);
    if (FIXNUM_POSITIVE_P(r) || (FIXNUM_ZERO_P(r) && !int_neg_p(num))) {
	n = rb_int_plus(n, f);
    }
    return n;
}

VALUE
rb_int_floor(VALUE num, int ndigits)
{
    VALUE f;

    if (int_round_zero_p(num, ndigits))
	return INT2FIX(0);
    f = int_pow(10, -ndigits);
    if (FIXNUM_P(num) && FIXNUM_P(f)) {
	SIGNED_VALUE x = FIX2LONG(num), y = FIX2LONG(f);
	int neg = x < 0;
	if (neg) x = -x + y - 1;
	x = x / y * y;
	if (neg) x = -x;
	return LONG2NUM(x);
    }
    if (RB_TYPE_P(f, T_FLOAT)) {
	/* then int_pow overflow */
	return INT2FIX(0);
    }
    return rb_int_minus(num, rb_int_modulo(num, f));
}

VALUE
rb_int_ceil(VALUE num, int ndigits)
{
    VALUE f;

    if (int_round_zero_p(num, ndigits))
	return INT2FIX(0);
    f = int_pow(10, -ndigits);
    if (FIXNUM_P(num) && FIXNUM_P(f)) {
	SIGNED_VALUE x = FIX2LONG(num), y = FIX2LONG(f);
	int neg = x < 0;
	if (neg) x = -x;
	else x += y - 1;
	x = (x / y) * y;
	if (neg) x = -x;
	return LONG2NUM(x);
    }
    if (RB_TYPE_P(f, T_FLOAT)) {
	/* then int_pow overflow */
	return INT2FIX(0);
    }
    return rb_int_plus(num, rb_int_minus(f, rb_int_modulo(num, f)));
}

VALUE
rb_int_truncate(VALUE num, int ndigits)
{
    VALUE f;
    VALUE m;

    if (int_round_zero_p(num, ndigits))
	return INT2FIX(0);
    f = int_pow(10, -ndigits);
    if (FIXNUM_P(num) && FIXNUM_P(f)) {
	SIGNED_VALUE x = FIX2LONG(num), y = FIX2LONG(f);
	int neg = x < 0;
	if (neg) x = -x;
	x = x / y * y;
	if (neg) x = -x;
	return LONG2NUM(x);
    }
    if (RB_TYPE_P(f, T_FLOAT)) {
	/* then int_pow overflow */
	return INT2FIX(0);
    }
    m = rb_int_modulo(num, f);
    if (int_neg_p(num)) {
	return rb_int_plus(num, rb_int_minus(f, m));
    }
    else {
	return rb_int_minus(num, m);
    }
}

/*
 *  call-seq:
 *     float.round([ndigits])  ->  integer or float
 *
 *  Rounds +float+ to a given precision in decimal digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is more than zero.
 *
 *     1.4.round      #=> 1
 *     1.5.round      #=> 2
 *     1.6.round      #=> 2
 *     (-1.5).round   #=> -2
 *
 *     1.234567.round(2)  #=> 1.23
 *     1.234567.round(3)  #=> 1.235
 *     1.234567.round(4)  #=> 1.2346
 *     1.234567.round(5)  #=> 1.23457
 *
 *     34567.89.round(-5) #=> 0
 *     34567.89.round(-4) #=> 30000
 *     34567.89.round(-3) #=> 35000
 *     34567.89.round(-2) #=> 34600
 *     34567.89.round(-1) #=> 34570
 *     34567.89.round(0)  #=> 34568
 *     34567.89.round(1)  #=> 34567.9
 *     34567.89.round(2)  #=> 34567.89
 *     34567.89.round(3)  #=> 34567.89
 *
 */

static VALUE
flo_round(int argc, VALUE *argv, VALUE num)
{
    double number, f;
    int ndigits = 0;

    if (rb_check_arity(argc, 0, 1)) {
	ndigits = NUM2INT(argv[0]);
    }
    if (ndigits < 0) {
	return rb_int_round(flo_to_i(num), ndigits);
    }
    number  = RFLOAT_VALUE(num);
    if (ndigits == 0) {
	return dbl2ival(round(number));
    }
    if (float_invariant_round(number, ndigits, &num)) return num;
    f = pow(10, ndigits);
    return DBL2NUM(round(number * f) / f);
}

static int
float_invariant_round(double number, int ndigits, VALUE *num)
{
    enum {float_dig = DBL_DIG+2};
    int binexp;

    frexp(number, &binexp);

/* Let `exp` be such that `number` is written as:"0.#{digits}e#{exp}",
   i.e. such that  10 ** (exp - 1) <= |number| < 10 ** exp
   Recall that up to float_dig digits can be needed to represent a double,
   so if ndigits + exp >= float_dig, the intermediate value (number * 10 ** ndigits)
   will be an integer and thus the result is the original number.
   If ndigits + exp <= 0, the result is 0 or "1e#{exp}", so
   if ndigits + exp < 0, the result is 0.
   We have:
	2 ** (binexp-1) <= |number| < 2 ** binexp
	10 ** ((binexp-1)/log_2(10)) <= |number| < 10 ** (binexp/log_2(10))
	If binexp >= 0, and since log_2(10) = 3.322259:
	   10 ** (binexp/4 - 1) < |number| < 10 ** (binexp/3)
	   floor(binexp/4) <= exp <= ceil(binexp/3)
	If binexp <= 0, swap the /4 and the /3
	So if ndigits + floor(binexp/(4 or 3)) >= float_dig, the result is number
	If ndigits + ceil(binexp/(3 or 4)) < 0 the result is 0
*/
    if (isinf(number) || isnan(number) ||
	(ndigits >= float_dig - (binexp > 0 ? binexp / 4 : binexp / 3 - 1))) {
	return TRUE;
    }
    if (ndigits < - (binexp > 0 ? binexp / 3 + 1 : binexp / 4)) {
	*num = DBL2NUM(0);
	return TRUE;
    }
    return FALSE;
}

/*
 *  call-seq:
 *     float.to_i      ->  integer
 *     float.to_int    ->  integer
 *
 *  Returns the +float+ truncated to an Integer.
 *
 *  Synonyms are #to_i and #to_int
 */

static VALUE
flo_to_i(VALUE num)
{
    double f = RFLOAT_VALUE(num);
    long val;

    if (f > 0.0) f = floor(f);
    if (f < 0.0) f = ceil(f);

    if (!FIXABLE(f)) {
	return rb_dbl2big(f);
    }
    val = (long)f;
    return LONG2FIX(val);
}

/*
 *  call-seq:
 *     float.truncate([ndigits])  ->  integer or float
 *
 *  Truncates +float+ to a given precision in decimal digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is more than zero.
 */
static VALUE
flo_truncate(int argc, VALUE *argv, VALUE num)
{
    if (signbit(RFLOAT_VALUE(num)))
	return flo_ceil(argc, argv, num);
    else
	return flo_floor(argc, argv, num);
}

/*
 *  call-seq:
 *     float.positive? ->  true or false
 *
 *  Returns +true+ if +float+ is greater than 0.
 */

static VALUE
flo_positive_p(VALUE num)
{
    double f = RFLOAT_VALUE(num);
    return f > 0.0 ? Qtrue : Qfalse;
}

/*
 *  call-seq:
 *     float.negative? ->  true or false
 *
 *  Returns +true+ if +float+ is less than 0.
 */

static VALUE
flo_negative_p(VALUE num)
{
    double f = RFLOAT_VALUE(num);
    return f < 0.0 ? Qtrue : Qfalse;
}

/*
 *  call-seq:
 *     num.floor([ndigits])  ->  integer or float
 *
 *  Returns the largest integer less than or equal to +num+.
 *
 *  Numeric implements this by converting an Integer to a Float and invoking
 *  Float#floor.
 *
 *     1.floor      #=> 1
 *     (-1).floor   #=> -1
 */

static VALUE
num_floor(int argc, VALUE *argv, VALUE num)
{
    return flo_floor(argc, argv, rb_Float(num));
}


/*
 *  call-seq:
 *     num.ceil([ndigits])  ->  integer or float
 *
 *  Returns the smallest possible Integer that is greater than or equal to
 *  +num+.
 *
 *  Numeric achieves this by converting itself to a Float then invoking
 *  Float#ceil.
 *
 *     1.ceil        #=> 1
 *     1.2.ceil      #=> 2
 *     (-1.2).ceil   #=> -1
 *     (-1.0).ceil   #=> -1
 */

static VALUE
num_ceil(int argc, VALUE *argv, VALUE num)
{
    return flo_ceil(argc, argv, rb_Float(num));
}

/*
 *  call-seq:
 *     num.round([ndigits])  ->  integer or float
 *
 *  Rounds +num+ to a given precision in decimal digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is more than zero.
 *
 *  Numeric implements this by converting itself to a Float and invoking
 *  Float#round.
 */

static VALUE
num_round(int argc, VALUE* argv, VALUE num)
{
    return flo_round(argc, argv, rb_Float(num));
}

/*
 *  call-seq:
 *     num.truncate([ndigits])  ->  integer or float
 *
 *  Returns +num+ truncated to an Integer.
 *
 *  Numeric implements this by converting its value to a Float and invoking
 *  Float#truncate.
 */

static VALUE
num_truncate(int argc, VALUE *argv, VALUE num)
{
    return flo_truncate(argc, argv, rb_Float(num));
}

static double
ruby_float_step_size(double beg, double end, double unit, int excl)
{
    const double epsilon = DBL_EPSILON;
    double n = (end - beg)/unit;
    double err = (fabs(beg) + fabs(end) + fabs(end-beg)) / fabs(unit) * epsilon;

    if (isinf(unit)) {
	return unit > 0 ? beg <= end : beg >= end;
    }
    if (unit == 0) {
	return INFINITY;
    }
    if (err>0.5) err=0.5;
    if (excl) {
	if (n<=0) return 0;
	if (n<1)
	    n = 0;
	else
	    n = floor(n - err);
    }
    else {
	if (n<0) return 0;
	n = floor(n + err);
    }
    return n+1;
}

int
ruby_float_step(VALUE from, VALUE to, VALUE step, int excl)
{
    if (RB_TYPE_P(from, T_FLOAT) || RB_TYPE_P(to, T_FLOAT) || RB_TYPE_P(step, T_FLOAT)) {
	double beg = NUM2DBL(from);
	double end = NUM2DBL(to);
	double unit = NUM2DBL(step);
	double n = ruby_float_step_size(beg, end, unit, excl);
	long i;

	if (isinf(unit)) {
	    /* if unit is infinity, i*unit+beg is NaN */
	    if (n) rb_yield(DBL2NUM(beg));
	}
	else if (unit == 0) {
	    VALUE val = DBL2NUM(beg);
	    for (;;)
		rb_yield(val);
	}
	else {
	    for (i=0; i<n; i++) {
		double d = i*unit+beg;
		if (unit >= 0 ? end < d : d < end) d = end;
		rb_yield(DBL2NUM(d));
	    }
	}
	return TRUE;
    }
    return FALSE;
}

VALUE
ruby_num_interval_step_size(VALUE from, VALUE to, VALUE step, int excl)
{
    if (FIXNUM_P(from) && FIXNUM_P(to) && FIXNUM_P(step)) {
	long delta, diff;

	diff = FIX2LONG(step);
	if (diff == 0) {
	    return DBL2NUM(INFINITY);
	}
	delta = FIX2LONG(to) - FIX2LONG(from);
	if (diff < 0) {
	    diff = -diff;
	    delta = -delta;
	}
	if (excl) {
	    delta--;
	}
	if (delta < 0) {
	    return INT2FIX(0);
	}
	return ULONG2NUM(delta / diff + 1UL);
    }
    else if (RB_TYPE_P(from, T_FLOAT) || RB_TYPE_P(to, T_FLOAT) || RB_TYPE_P(step, T_FLOAT)) {
	double n = ruby_float_step_size(NUM2DBL(from), NUM2DBL(to), NUM2DBL(step), excl);

	if (isinf(n)) return DBL2NUM(n);
	if (POSFIXABLE(n)) return LONG2FIX(n);
	return rb_dbl2big(n);
    }
    else {
	VALUE result;
	ID cmp = '>';
	switch (rb_cmpint(rb_num_coerce_cmp(step, INT2FIX(0), id_cmp), step, INT2FIX(0))) {
	  case 0: return DBL2NUM(INFINITY);
	  case -1: cmp = '<'; break;
	}
	if (RTEST(rb_funcall(from, cmp, 1, to))) return INT2FIX(0);
	result = rb_funcall(rb_funcall(to, '-', 1, from), id_div, 1, step);
	if (!excl || RTEST(rb_funcall(rb_funcall(from, '+', 1, rb_funcall(result, '*', 1, step)), cmp, 1, to))) {
	    result = rb_funcall(result, '+', 1, INT2FIX(1));
	}
	return result;
    }
}

static VALUE
num_step_compare_with_zero(VALUE num)
{
    VALUE zero = INT2FIX(0);
    return rb_check_funcall(num, '>', 1, &zero);
}

static int
num_step_negative_p(VALUE num)
{
    const ID mid = '<';
    VALUE r;

    if (FIXNUM_P(num)) {
	if (method_basic_p(rb_cFixnum))
	    return (SIGNED_VALUE)num < 0;
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	if (method_basic_p(rb_cBignum))
	    return BIGNUM_NEGATIVE_P(num);
    }
    r = rb_rescue(num_step_compare_with_zero, num, coerce_rescue_quiet, Qnil);
    if (r == Qundef) {
	coerce_failed(num, INT2FIX(0));
    }
    return !RTEST(r);
}

static int
num_step_scan_args(int argc, const VALUE *argv, VALUE *to, VALUE *step)
{
    VALUE hash;
    int desc;

    argc = rb_scan_args(argc, argv, "02:", to, step, &hash);
    if (!NIL_P(hash)) {
	ID keys[2];
	VALUE values[2];
	keys[0] = id_to;
	keys[1] = id_by;
	rb_get_kwargs(hash, keys, 0, 2, values);
	if (values[0] != Qundef) {
	    if (argc > 0) rb_raise(rb_eArgError, "to is given twice");
	    *to = values[0];
	}
	if (values[1] != Qundef) {
	    if (argc > 1) rb_raise(rb_eArgError, "step is given twice");
	    *step = values[1];
	}
    }
    else {
	/* compatibility */
	if (argc > 1 && NIL_P(*step)) {
	    rb_raise(rb_eTypeError, "step must be numeric");
	}
	if (rb_equal(*step, INT2FIX(0))) {
	    rb_raise(rb_eArgError, "step can't be 0");
	}
    }
    if (NIL_P(*step)) {
	*step = INT2FIX(1);
    }
    desc = num_step_negative_p(*step);
    if (NIL_P(*to)) {
	*to = desc ? DBL2NUM(-INFINITY) : DBL2NUM(INFINITY);
    }
    return desc;
}

static VALUE
num_step_size(VALUE from, VALUE args, VALUE eobj)
{
    VALUE to, step;
    int argc = args ? RARRAY_LENINT(args) : 0;
    const VALUE *argv = args ? RARRAY_CONST_PTR(args) : 0;

    num_step_scan_args(argc, argv, &to, &step);

    return ruby_num_interval_step_size(from, to, step, FALSE);
}
/*
 *  call-seq:
 *     num.step(by: step, to: limit) {|i| block }   ->  self
 *     num.step(by: step, to: limit)		    ->  an_enumerator
 *     num.step(limit=nil, step=1) {|i| block }     ->  self
 *     num.step(limit=nil, step=1)                  ->  an_enumerator
 *
 *  Invokes the given block with the sequence of numbers starting at +num+,
 *  incremented by +step+ (defaulted to +1+) on each call.
 *
 *  The loop finishes when the value to be passed to the block is greater than
 *  +limit+ (if +step+ is positive) or less than +limit+ (if +step+ is
 *  negative), where <i>limit</i> is defaulted to infinity.
 *
 *  In the recommended keyword argument style, either or both of
 *  +step+ and +limit+ (default infinity) can be omitted.  In the
 *  fixed position argument style, zero as a step
 *  (i.e. num.step(limit, 0)) is not allowed for historical
 *  compatibility reasons.
 *
 *  If all the arguments are integers, the loop operates using an integer
 *  counter.
 *
 *  If any of the arguments are floating point numbers, all are converted to floats, and the loop is executed the following expression:
 *
 *	floor(n + n*epsilon)+ 1
 *
 *  Where the +n+ is the following:
 *
 *	n = (limit - num)/step
 *
 *  Otherwise, the loop starts at +num+, uses either the less-than (<) or
 *  greater-than (>) operator to compare the counter against +limit+, and
 *  increments itself using the <code>+</code> operator.
 *
 *  If no block is given, an Enumerator is returned instead.
 *
 *  For example:
 *
 *     p 1.step.take(4)
 *     p 10.step(by: -1).take(4)
 *     3.step(to: 5) { |i| print i, " " }
 *     1.step(10, 2) { |i| print i, " " }
 *     Math::E.step(to: Math::PI, by: 0.2) { |f| print f, " " }
 *
 *  Will produce:
 *
 *     [1, 2, 3, 4]
 *     [10, 9, 8, 7]
 *     3 4 5
 *     1 3 5 7 9
 *     2.71828182845905 2.91828182845905 3.11828182845905
 */

static VALUE
num_step(int argc, VALUE *argv, VALUE from)
{
    VALUE to, step;
    int desc, inf;

    RETURN_SIZED_ENUMERATOR(from, argc, argv, num_step_size);

    desc = num_step_scan_args(argc, argv, &to, &step);
    if (rb_equal(step, INT2FIX(0))) {
	inf = 1;
    }
    else if (RB_TYPE_P(to, T_FLOAT)) {
	double f = RFLOAT_VALUE(to);
	inf = isinf(f) && (signbit(f) ? desc : !desc);
    }
    else inf = 0;

    if (FIXNUM_P(from) && (inf || FIXNUM_P(to)) && FIXNUM_P(step)) {
	long i = FIX2LONG(from);
	long diff = FIX2LONG(step);

	if (inf) {
	    for (;; i += diff)
		rb_yield(LONG2FIX(i));
	}
	else {
	    long end = FIX2LONG(to);

	    if (desc) {
		for (; i >= end; i += diff)
		    rb_yield(LONG2FIX(i));
	    }
	    else {
		for (; i <= end; i += diff)
		    rb_yield(LONG2FIX(i));
	    }
	}
    }
    else if (!ruby_float_step(from, to, step, FALSE)) {
	VALUE i = from;

	if (inf) {
	    for (;; i = rb_funcall(i, '+', 1, step))
		rb_yield(i);
	}
	else {
	    ID cmp = desc ? '<' : '>';

	    for (; !RTEST(rb_funcall(i, cmp, 1, to)); i = rb_funcall(i, '+', 1, step))
		rb_yield(i);
	}
    }
    return from;
}

static char *
out_of_range_float(char (*pbuf)[24], VALUE val)
{
    char *const buf = *pbuf;
    char *s;

    snprintf(buf, sizeof(*pbuf), "%-.10g", RFLOAT_VALUE(val));
    if ((s = strchr(buf, ' ')) != 0) *s = '\0';
    return buf;
}

#define FLOAT_OUT_OF_RANGE(val, type) do { \
    char buf[24]; \
    rb_raise(rb_eRangeError, "float %s out of range of "type, \
	     out_of_range_float(&buf, (val))); \
} while (0)

#define LONG_MIN_MINUS_ONE ((double)LONG_MIN-1)
#define LONG_MAX_PLUS_ONE (2*(double)(LONG_MAX/2+1))
#define ULONG_MAX_PLUS_ONE (2*(double)(ULONG_MAX/2+1))
#define LONG_MIN_MINUS_ONE_IS_LESS_THAN(n) \
  (LONG_MIN_MINUS_ONE == (double)LONG_MIN ? \
   LONG_MIN <= (n): \
   LONG_MIN_MINUS_ONE < (n))

long
rb_num2long(VALUE val)
{
  again:
    if (NIL_P(val)) {
	rb_raise(rb_eTypeError, "no implicit conversion from nil to integer");
    }

    if (FIXNUM_P(val)) return FIX2LONG(val);

    else if (RB_TYPE_P(val, T_FLOAT)) {
	if (RFLOAT_VALUE(val) < LONG_MAX_PLUS_ONE
	    && LONG_MIN_MINUS_ONE_IS_LESS_THAN(RFLOAT_VALUE(val))) {
	    return (long)RFLOAT_VALUE(val);
	}
	else {
	    FLOAT_OUT_OF_RANGE(val, "integer");
	}
    }
    else if (RB_TYPE_P(val, T_BIGNUM)) {
	return rb_big2long(val);
    }
    else {
	val = rb_to_int(val);
	goto again;
    }
}

static unsigned long
rb_num2ulong_internal(VALUE val, int *wrap_p)
{
  again:
    if (NIL_P(val)) {
       rb_raise(rb_eTypeError, "no implicit conversion from nil to integer");
    }

    if (FIXNUM_P(val)) {
        long l = FIX2LONG(val); /* this is FIX2LONG, inteneded */
        if (wrap_p)
            *wrap_p = l < 0;
        return (unsigned long)l;
    }
    else if (RB_TYPE_P(val, T_FLOAT)) {
       if (RFLOAT_VALUE(val) < ULONG_MAX_PLUS_ONE
           && LONG_MIN_MINUS_ONE_IS_LESS_THAN(RFLOAT_VALUE(val))) {
           double d = RFLOAT_VALUE(val);
           if (wrap_p)
               *wrap_p = d <= -1.0; /* NUM2ULONG(v) uses v.to_int conceptually.  */
           if (0 <= d)
               return (unsigned long)d;
           return (unsigned long)(long)d;
       }
       else {
	   FLOAT_OUT_OF_RANGE(val, "integer");
       }
    }
    else if (RB_TYPE_P(val, T_BIGNUM)) {
        {
            unsigned long ul = rb_big2ulong(val);
            if (wrap_p)
                *wrap_p = BIGNUM_NEGATIVE_P(val);
            return ul;
        }
    }
    else {
        val = rb_to_int(val);
        goto again;
    }
}

unsigned long
rb_num2ulong(VALUE val)
{
    return rb_num2ulong_internal(val, NULL);
}

#if SIZEOF_INT < SIZEOF_LONG
void
rb_out_of_int(SIGNED_VALUE num)
{
    rb_raise(rb_eRangeError, "integer %"PRIdVALUE " too %s to convert to `int'",
	     num, num < 0 ? "small" : "big");
}

static void
check_int(long num)
{
    if ((long)(int)num != num) {
	rb_out_of_int(num);
    }
}

static void
check_uint(unsigned long num, int sign)
{
    if (sign) {
	/* minus */
	if (num < (unsigned long)INT_MIN)
	    rb_raise(rb_eRangeError, "integer %ld too small to convert to `unsigned int'", (long)num);
    }
    else {
	/* plus */
	if (UINT_MAX < num)
	    rb_raise(rb_eRangeError, "integer %lu too big to convert to `unsigned int'", num);
    }
}

long
rb_num2int(VALUE val)
{
    long num = rb_num2long(val);

    check_int(num);
    return num;
}

long
rb_fix2int(VALUE val)
{
    long num = FIXNUM_P(val)?FIX2LONG(val):rb_num2long(val);

    check_int(num);
    return num;
}

unsigned long
rb_num2uint(VALUE val)
{
    int wrap;
    unsigned long num = rb_num2ulong_internal(val, &wrap);

    check_uint(num, wrap);
    return num;
}

unsigned long
rb_fix2uint(VALUE val)
{
    unsigned long num;

    if (!FIXNUM_P(val)) {
	return rb_num2uint(val);
    }
    num = FIX2ULONG(val);

    check_uint(num, negative_int_p(val));
    return num;
}
#else
long
rb_num2int(VALUE val)
{
    return rb_num2long(val);
}

long
rb_fix2int(VALUE val)
{
    return FIX2INT(val);
}
#endif

void
rb_out_of_short(SIGNED_VALUE num)
{
    rb_raise(rb_eRangeError, "integer %"PRIdVALUE " too %s to convert to `short'",
	     num, num < 0 ? "small" : "big");
}

static void
check_short(long num)
{
    if ((long)(short)num != num) {
	rb_out_of_short(num);
    }
}

static void
check_ushort(unsigned long num, int sign)
{
    if (sign) {
	/* minus */
	if (num < (unsigned long)SHRT_MIN)
	    rb_raise(rb_eRangeError, "integer %ld too small to convert to `unsigned short'", (long)num);
    }
    else {
	/* plus */
	if (USHRT_MAX < num)
	    rb_raise(rb_eRangeError, "integer %lu too big to convert to `unsigned short'", num);
    }
}

short
rb_num2short(VALUE val)
{
    long num = rb_num2long(val);

    check_short(num);
    return num;
}

short
rb_fix2short(VALUE val)
{
    long num = FIXNUM_P(val)?FIX2LONG(val):rb_num2long(val);

    check_short(num);
    return num;
}

unsigned short
rb_num2ushort(VALUE val)
{
    int wrap;
    unsigned long num = rb_num2ulong_internal(val, &wrap);

    check_ushort(num, wrap);
    return num;
}

unsigned short
rb_fix2ushort(VALUE val)
{
    unsigned long num;

    if (!FIXNUM_P(val)) {
	return rb_num2ushort(val);
    }
    num = FIX2ULONG(val);

    check_ushort(num, negative_int_p(val));
    return num;
}

VALUE
rb_num2fix(VALUE val)
{
    long v;

    if (FIXNUM_P(val)) return val;

    v = rb_num2long(val);
    if (!FIXABLE(v))
	rb_raise(rb_eRangeError, "integer %ld out of range of fixnum", v);
    return LONG2FIX(v);
}

#if HAVE_LONG_LONG

#define LLONG_MIN_MINUS_ONE ((double)LLONG_MIN-1)
#define LLONG_MAX_PLUS_ONE (2*(double)(LLONG_MAX/2+1))
#define ULLONG_MAX_PLUS_ONE (2*(double)(ULLONG_MAX/2+1))
#ifndef ULLONG_MAX
#define ULLONG_MAX ((unsigned LONG_LONG)LLONG_MAX*2+1)
#endif
#define LLONG_MIN_MINUS_ONE_IS_LESS_THAN(n) \
  (LLONG_MIN_MINUS_ONE == (double)LLONG_MIN ? \
   LLONG_MIN <= (n): \
   LLONG_MIN_MINUS_ONE < (n))

LONG_LONG
rb_num2ll(VALUE val)
{
    if (NIL_P(val)) {
	rb_raise(rb_eTypeError, "no implicit conversion from nil");
    }

    if (FIXNUM_P(val)) return (LONG_LONG)FIX2LONG(val);

    else if (RB_TYPE_P(val, T_FLOAT)) {
	if (RFLOAT_VALUE(val) < LLONG_MAX_PLUS_ONE
            && (LLONG_MIN_MINUS_ONE_IS_LESS_THAN(RFLOAT_VALUE(val)))) {
	    return (LONG_LONG)(RFLOAT_VALUE(val));
	}
	else {
	    FLOAT_OUT_OF_RANGE(val, "long long");
	}
    }
    else if (RB_TYPE_P(val, T_BIGNUM)) {
	return rb_big2ll(val);
    }
    else if (RB_TYPE_P(val, T_STRING)) {
	rb_raise(rb_eTypeError, "no implicit conversion from string");
    }
    else if (RB_TYPE_P(val, T_TRUE) || RB_TYPE_P(val, T_FALSE)) {
	rb_raise(rb_eTypeError, "no implicit conversion from boolean");
    }

    val = rb_to_int(val);
    return NUM2LL(val);
}

unsigned LONG_LONG
rb_num2ull(VALUE val)
{
    if (RB_TYPE_P(val, T_NIL)) {
	rb_raise(rb_eTypeError, "no implicit conversion from nil");
    }
    else if (RB_TYPE_P(val, T_FIXNUM)) {
	return (LONG_LONG)FIX2LONG(val); /* this is FIX2LONG, inteneded */
    }
    else if (RB_TYPE_P(val, T_FLOAT)) {
	if (RFLOAT_VALUE(val) < ULLONG_MAX_PLUS_ONE
            && LLONG_MIN_MINUS_ONE_IS_LESS_THAN(RFLOAT_VALUE(val))) {
            if (0 <= RFLOAT_VALUE(val))
                return (unsigned LONG_LONG)(RFLOAT_VALUE(val));
	    return (unsigned LONG_LONG)(LONG_LONG)(RFLOAT_VALUE(val));
	}
	else {
	    FLOAT_OUT_OF_RANGE(val, "unsigned long long");
	}
    }
    else if (RB_TYPE_P(val, T_BIGNUM)) {
	return rb_big2ull(val);
    }
    else if (RB_TYPE_P(val, T_STRING)) {
	rb_raise(rb_eTypeError, "no implicit conversion from string");
    }
    else if (RB_TYPE_P(val, T_TRUE) || RB_TYPE_P(val, T_FALSE)) {
	rb_raise(rb_eTypeError, "no implicit conversion from boolean");
    }

    val = rb_to_int(val);
    return NUM2ULL(val);
}

#endif  /* HAVE_LONG_LONG */

/*
 * Document-class: Integer
 *
 *  This class is the basis for the two concrete classes that hold whole
 *  numbers, Bignum and Fixnum.
 *
 */

/*
 *  call-seq:
 *     int.to_i      ->  integer
 *
 *  As +int+ is already an Integer, all these methods simply return the receiver.
 *
 *  Synonyms is #to_int
 */

static VALUE
int_to_i(VALUE num)
{
    return num;
}

/*
 *  call-seq:
 *     int.integer?  ->  true
 *
 *  Since +int+ is already an Integer, this always returns +true+.
 */

static VALUE
int_int_p(VALUE num)
{
    return Qtrue;
}

/*
 *  call-seq:
 *     int.odd?  ->  true or false
 *
 *  Returns +true+ if +int+ is an odd number.
 */

static VALUE
int_odd_p(VALUE num)
{
    if (FIXNUM_P(num)) {
	if (num & 2) {
	    return Qtrue;
	}
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_odd_p(num);
    }
    else if (rb_funcall(num, '%', 1, INT2FIX(2)) != INT2FIX(0)) {
	return Qtrue;
    }
    return Qfalse;
}

/*
 *  call-seq:
 *     int.even?  ->  true or false
 *
 *  Returns +true+ if +int+ is an even number.
 */

static VALUE
int_even_p(VALUE num)
{
    if (FIXNUM_P(num)) {
	if ((num & 2) == 0) {
	    return Qtrue;
	}
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_even_p(num);
    }
    else if (rb_funcall(num, '%', 1, INT2FIX(2)) == INT2FIX(0)) {
	return Qtrue;
    }
    return Qfalse;
}

/*
 *  call-seq:
 *     int.next  ->  integer
 *     int.succ  ->  integer
 *
 *  Returns the Integer equal to +int+ + 1.
 *
 *     1.next      #=> 2
 *     (-1).next   #=> 0
 */

static VALUE
fix_succ(VALUE num)
{
    long i = FIX2LONG(num) + 1;
    return LONG2NUM(i);
}

/*
 *  call-seq:
 *     int.next  ->  integer
 *     int.succ  ->  integer
 *
 *  Returns the Integer equal to +int+ + 1, same as Fixnum#next.
 *
 *     1.next      #=> 2
 *     (-1).next   #=> 0
 */

VALUE
rb_int_succ(VALUE num)
{
    if (FIXNUM_P(num)) {
	long i = FIX2LONG(num) + 1;
	return LONG2NUM(i);
    }
    if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_plus(num, INT2FIX(1));
    }
    return rb_funcall(num, '+', 1, INT2FIX(1));
}

#define int_succ rb_int_succ

/*
 *  call-seq:
 *     int.pred  ->  integer
 *
 *  Returns the Integer equal to +int+ - 1.
 *
 *     1.pred      #=> 0
 *     (-1).pred   #=> -2
 */

VALUE
rb_int_pred(VALUE num)
{
    if (FIXNUM_P(num)) {
	long i = FIX2LONG(num) - 1;
	return LONG2NUM(i);
    }
    if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_minus(num, INT2FIX(1));
    }
    return rb_funcall(num, '-', 1, INT2FIX(1));
}

#define int_pred rb_int_pred

/*
 *  Document-method: Integer#chr
 *  call-seq:
 *     int.chr([encoding])  ->  string
 *
 *  Returns a string containing the character represented by the +int+'s value
 *  according to +encoding+.
 *
 *     65.chr    #=> "A"
 *     230.chr   #=> "\346"
 *     255.chr(Encoding::UTF_8)   #=> "\303\277"
 */

VALUE
rb_enc_uint_chr(unsigned int code, rb_encoding *enc)
{
    int n;
    VALUE str;
    switch (n = rb_enc_codelen(code, enc)) {
      case ONIGERR_INVALID_CODE_POINT_VALUE:
	rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
	break;
      case ONIGERR_TOO_BIG_WIDE_CHAR_VALUE:
      case 0:
	rb_raise(rb_eRangeError, "%u out of char range", code);
	break;
    }
    str = rb_enc_str_new(0, n, enc);
    rb_enc_mbcput(code, RSTRING_PTR(str), enc);
    if (rb_enc_precise_mbclen(RSTRING_PTR(str), RSTRING_END(str), enc) != n) {
	rb_raise(rb_eRangeError, "invalid codepoint 0x%X in %s", code, rb_enc_name(enc));
    }
    return str;
}

static VALUE
int_chr(int argc, VALUE *argv, VALUE num)
{
    char c;
    unsigned int i;
    rb_encoding *enc;

    if (rb_num_to_uint(num, &i) == 0) {
    }
    else if (FIXNUM_P(num)) {
	rb_raise(rb_eRangeError, "%ld out of char range", FIX2LONG(num));
    }
    else {
	rb_raise(rb_eRangeError, "bignum out of char range");
    }

    switch (argc) {
      case 0:
	if (0xff < i) {
	    enc = rb_default_internal_encoding();
	    if (!enc) {
		rb_raise(rb_eRangeError, "%d out of char range", i);
	    }
	    goto decode;
	}
	c = (char)i;
	if (i < 0x80) {
	    return rb_usascii_str_new(&c, 1);
	}
	else {
	    return rb_str_new(&c, 1);
	}
      case 1:
	break;
      default:
	rb_check_arity(argc, 0, 1);
	break;
    }
    enc = rb_to_encoding(argv[0]);
    if (!enc) enc = rb_ascii8bit_encoding();
  decode:
    return rb_enc_uint_chr(i, enc);
}

/*
 *  call-seq:
 *     int.ord  ->  self
 *
 *  Returns the +int+ itself.
 *
 *     ?a.ord    #=> 97
 *
 *  This method is intended for compatibility to character constant in Ruby
 *  1.9.
 *
 *  For example, ?a.ord returns 97 both in 1.8 and 1.9.
 */

static VALUE
int_ord(VALUE num)
{
    return num;
}

/********************************************************************
 *
 * Document-class: Fixnum
 *
 *  Holds Integer values that can be represented in a native machine word
 *  (minus 1 bit).  If any operation on a Fixnum exceeds this range, the value
 *  is automatically converted to a Bignum.
 *
 *  Fixnum objects have immediate value. This means that when they are assigned
 *  or passed as parameters, the actual object is passed, rather than a
 *  reference to that object.
 *
 *  Assignment does not alias Fixnum objects. There is effectively only one
 *  Fixnum object instance for any given integer value, so, for example, you
 *  cannot add a singleton method to a Fixnum. Any attempt to add a singleton
 *  method to a Fixnum object will raise a TypeError.
 */


/*
 * Document-method: Integer#-@
 * call-seq:
 *   -int  ->  integer
 *
 * Negates +int+.
 * (returns an integer whose value is 0-int)
 */

static VALUE
fix_uminus(VALUE num)
{
    return LONG2NUM(-FIX2LONG(num));
}

VALUE
rb_int_uminus(VALUE num)
{
    if (FIXNUM_P(num)) {
	return fix_uminus(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_uminus(num);
    }
    return rb_funcall(num, idUMinus, 0, 0);
}

/*
 *  Document-method: Integer#to_s
 *  call-seq:
 *     int.to_s(base=10)  ->  string
 *
 *  Returns a string containing the representation of +int+ radix +base+
 *  (between 2 and 36).
 *
 *     12345.to_s       #=> "12345"
 *     12345.to_s(2)    #=> "11000000111001"
 *     12345.to_s(8)    #=> "30071"
 *     12345.to_s(10)   #=> "12345"
 *     12345.to_s(16)   #=> "3039"
 *     12345.to_s(36)   #=> "9ix"
 *     78546939656932.to_s(36)  #=> "rubyrules"
 *
 */

VALUE
rb_fix2str(VALUE x, int base)
{
    char buf[SIZEOF_VALUE*CHAR_BIT + 1], *const e = buf + sizeof buf, *b = e;
    long val = FIX2LONG(x);
    unsigned long u;
    int neg = 0;

    if (base < 2 || 36 < base) {
	rb_raise(rb_eArgError, "invalid radix %d", base);
    }
    if (val == 0) {
	return rb_usascii_str_new2("0");
    }
    if (val < 0) {
	u = 1 + (unsigned long)(-(val + 1)); /* u = -val avoiding overflow */
	neg = 1;
    }
    else {
	u = val;
    }
    do {
	*--b = ruby_digitmap[(int)(u % base)];
    } while (u /= base);
    if (neg) {
	*--b = '-';
    }

    return rb_usascii_str_new(b, e - b);
}

static VALUE
int_to_s(int argc, VALUE *argv, VALUE x)
{
    int base;

    if (rb_check_arity(argc, 0, 1))
	base = NUM2INT(argv[0]);
    else
	base = 10;
    return rb_int2str(x, base);
}

VALUE
rb_int2str(VALUE x, int base)
{
    if (FIXNUM_P(x)) {
	return rb_fix2str(x, base);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big2str(x, base);
    }

    return rb_any_to_s(x);
}

/*
 * Document-method: Integer#+
 * Document-method: Fixnum#+
 * call-seq:
 *   int + numeric  ->  numeric_result
 *
 * Performs addition: the class of the resulting object depends on the class of
 * +numeric+ and on the magnitude of the result. It may return a Bignum.
 */

static VALUE
fix_plus(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	long a, b, c;
	VALUE r;

	a = FIX2LONG(x);
	b = FIX2LONG(y);
	c = a + b;
	r = LONG2NUM(c);

	return r;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_plus(y, x);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM((double)FIX2LONG(x) + RFLOAT_VALUE(y));
    }
    else if (RB_TYPE_P(y, T_COMPLEX)) {
	VALUE rb_nucomp_add(VALUE, VALUE);
	return rb_nucomp_add(y, x);
    }
    else {
	return rb_num_coerce_bin(x, y, '+');
    }
}

VALUE
rb_fix_plus(VALUE x, VALUE y)
{
    return fix_plus(x, y);
}

VALUE
rb_int_plus(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_plus(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_plus(x, y);
    }
    return rb_num_coerce_bin(x, y, '+');
}

/*
 * Document-method: Integer#-
 * Document-method: Fixnum#-
 * call-seq:
 *   int - numeric  ->  numeric_result
 *
 * Performs subtraction: the class of the resulting object depends on the class
 * of +numeric+ and on the magnitude of the result. It may return a Bignum.
 */

static VALUE
fix_minus(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	long a, b, c;
	VALUE r;

	a = FIX2LONG(x);
	b = FIX2LONG(y);
	c = a - b;
	r = LONG2NUM(c);

	return r;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	x = rb_int2big(FIX2LONG(x));
	return rb_big_minus(x, y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM((double)FIX2LONG(x) - RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, '-');
    }
}

VALUE
rb_int_minus(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_minus(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_minus(x, y);
    }
    return rb_num_coerce_bin(x, y, '-');
}


#define SQRT_LONG_MAX ((SIGNED_VALUE)1<<((SIZEOF_LONG*CHAR_BIT-1)/2))
/*tests if N*N would overflow*/
#define FIT_SQRT_LONG(n) (((n)<SQRT_LONG_MAX)&&((n)>=-SQRT_LONG_MAX))

/*
 * Document-method: Integer#*
 * Document-method: Fixnum#*
 * call-seq:
 *   int * numeric  ->  numeric_result
 *
 * Performs multiplication: the class of the resulting object depends on the
 * class of +numeric+ and on the magnitude of the result. It may return a
 * Bignum.
 */

static VALUE
fix_mul(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	return rb_fix_mul_fix(x, y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_mul(y, x);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM((double)FIX2LONG(x) * RFLOAT_VALUE(y));
    }
    else if (RB_TYPE_P(y, T_COMPLEX)) {
	VALUE rb_nucomp_mul(VALUE, VALUE);
	return rb_nucomp_mul(y, x);
    }
    else {
	return rb_num_coerce_bin(x, y, '*');
    }
}

VALUE
rb_int_mul(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_mul(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_mul(x, y);
    }
    return rb_num_coerce_bin(x, y, '*');
}

/*
 *  Document-method: Integer#fdiv
 *  call-seq:
 *     integer.fdiv(numeric)  ->  float
 *
 *  Returns the floating point result of dividing +fix+ by +numeric+.
 *
 *     654321.fdiv(13731)      #=> 47.6528293642124
 *     654321.fdiv(13731.24)   #=> 47.6519964693647
 *
 *     -1234567890987654321.fdiv(13731)      #=> -89910996357705.5
 *     -1234567890987654321.fdiv(13731.24)   #=> -89909424858035.7
 *
 */

static VALUE
fix_fdiv(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	return DBL2NUM((double)FIX2LONG(x) / (double)FIX2LONG(y));
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_fdiv(rb_int2big(FIX2LONG(x)), y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM((double)FIX2LONG(x) / RFLOAT_VALUE(y));
    }
    else {
	return rb_num_coerce_bin(x, y, rb_intern("fdiv"));
    }
}

static VALUE
int_fdiv(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_fdiv(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_fdiv(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#/
 * Document-method: Fixnum#/
 * call-seq:
 *   int / numeric  ->  numeric_result
 *
 * Performs division: the class of the resulting object depends on the class of
 * +numeric+ and on the magnitude of the result. It may return a Bignum.
 */

static VALUE
fix_divide(VALUE x, VALUE y, ID op)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(y) == 0) rb_num_zerodiv();
	return rb_fix_div_fix(x, y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	x = rb_int2big(FIX2LONG(x));
	return rb_big_div(x, y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	{
	    double div;

	    if (op == '/') {
		div = (double)FIX2LONG(x) / RFLOAT_VALUE(y);
		return DBL2NUM(div);
	    }
	    else {
		if (RFLOAT_VALUE(y) == 0) rb_num_zerodiv();
		div = (double)FIX2LONG(x) / RFLOAT_VALUE(y);
		return rb_dbl2big(floor(div));
	    }
	}
    }
    else {
	if (RB_TYPE_P(y, T_RATIONAL) &&
	    op == '/' && FIX2LONG(x) == 1)
	    return rb_rational_reciprocal(y);
	return rb_num_coerce_bin(x, y, op);
    }
}

static VALUE
fix_div(VALUE x, VALUE y)
{
    return fix_divide(x, y, '/');
}

VALUE
rb_int_div(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_div(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_div(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#div
 * call-seq:
 *   int.div(numeric)  ->  integer
 *
 * Performs integer division: returns integer result of dividing +int+ by
 * +numeric+.
 */

static VALUE
fix_idiv(VALUE x, VALUE y)
{
    return fix_divide(x, y, id_div);
}

VALUE
rb_int_idiv(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_idiv(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_idiv(x, y);
    }
    return num_div(x, y);
}

/*
 *  Document-method: Fixnum#%
 *  Document-method: Integer#modulo
 *  call-seq:
 *    fix % other        ->  real
 *    fix.modulo(other)  ->  real
 *
 *  Returns +fix+ modulo +other+.
 *
 *  See Numeric#divmod for more information.
 */

static VALUE
fix_mod(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(y) == 0) rb_num_zerodiv();
	return rb_fix_mod_fix(x, y);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	x = rb_int2big(FIX2LONG(x));
	return rb_big_modulo(x, y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return DBL2NUM(ruby_float_mod((double)FIX2LONG(x), RFLOAT_VALUE(y)));
    }
    else {
	return rb_num_coerce_bin(x, y, '%');
    }
}

VALUE
rb_int_modulo(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_mod(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_modulo(x, y);
    }
    return num_modulo(x, y);
}

/*
 *  call-seq:
 *     int.remainder(numeric)  ->  real
 *
 *
 *  Returns the remainder after dividing <i>big</i> by <i>numeric</i> as:
 *
 *    x.remainder(y) means x-y*(x/y).truncate
 *
 *  Examples
 *
 *    5.remainder(3)    #=> 2
 *    -5.remainder(3)   #=> -2
 *    5.remainder(-3)   #=> 2
 *    -5.remainder(-3)  #=> -2
 *
 *    -1234567890987654321.remainder(13731)      #=> -6966
 *    -1234567890987654321.remainder(13731.24)   #=> -9906.22531493148
 *
 *  See Numeric#divmod.
 */

VALUE
int_remainder(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return num_remainder(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_remainder(x, y);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#divmod
 *  call-seq:
 *     integer.divmod(numeric)  ->  array
 *
 *  See <code>Numeric#divmod</code>.
 */
static VALUE
fix_divmod(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	VALUE div, mod;
	if (FIX2LONG(y) == 0) rb_num_zerodiv();
	rb_fix_divmod_fix(x, y, &div, &mod);
	return rb_assoc_new(div, mod);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	x = rb_int2big(FIX2LONG(x));
	return rb_big_divmod(x, y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	{
	    double div, mod;
	    volatile VALUE a, b;

	    flodivmod((double)FIX2LONG(x), RFLOAT_VALUE(y), &div, &mod);
	    a = dbl2ival(div);
	    b = DBL2NUM(mod);
	    return rb_assoc_new(a, b);
	}
    }
    else {
	return rb_num_coerce_bin(x, y, id_divmod);
    }
}

static VALUE
int_divmod(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_divmod(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_divmod(x, y);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#**
 *  call-seq:
 *    integer ** numeric  ->  numeric_result
 *
 *  Raises +integer+ to the power of +numeric+, which may be negative or
 *  fractional.
 *  The result may be a Fixnum, Bignum, or Float
 *
 *    2 ** 3      #=> 8
 *    2 ** -1     #=> (1/2)
 *    2 ** 0.5    #=> 1.4142135623731
 *
 *    123456789 ** 2      #=> 15241578750190521
 *    123456789 ** 1.2    #=> 5126464716.09932
 *    123456789 ** -2     #=> 6.5610001194102e-17
 *
 */

static VALUE
int_pow(long x, unsigned long y)
{
    int neg = x < 0;
    long z = 1;

    if (neg) x = -x;
    if (y & 1)
	z = x;
    else
	neg = 0;
    y &= ~1;
    do {
	while (y % 2 == 0) {
	    if (!FIT_SQRT_LONG(x)) {
		VALUE v;
	      bignum:
		v = rb_big_pow(rb_int2big(x), LONG2NUM(y));
		if (z != 1) v = rb_big_mul(rb_int2big(neg ? -z : z), v);
		return v;
	    }
	    x = x * x;
	    y >>= 1;
	}
	{
            if (MUL_OVERFLOW_FIXNUM_P(x, z)) {
		goto bignum;
	    }
	    z = x * z;
	}
    } while (--y);
    if (neg) z = -z;
    return LONG2NUM(z);
}

VALUE
rb_int_positive_pow(long x, unsigned long y)
{
    return int_pow(x, y);
}

static VALUE
fix_pow(VALUE x, VALUE y)
{
    long a = FIX2LONG(x);

    if (FIXNUM_P(y)) {
	long b = FIX2LONG(y);

	if (a == 1) return INT2FIX(1);
	if (a == -1) {
	    if (b % 2 == 0)
		return INT2FIX(1);
	    else
		return INT2FIX(-1);
	}
	if (b < 0)
	    return rb_funcall(rb_rational_raw1(x), idPow, 1, y);

	if (b == 0) return INT2FIX(1);
	if (b == 1) return x;
	if (a == 0) {
	    if (b > 0) return INT2FIX(0);
	    return DBL2NUM(INFINITY);
	}
	return int_pow(a, b);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	if (a == 1) return INT2FIX(1);
	if (a == -1) {
	    if (int_even_p(y)) return INT2FIX(1);
	    else return INT2FIX(-1);
	}
	if (negative_int_p(y))
	    return rb_funcall(rb_rational_raw1(x), idPow, 1, y);
	if (a == 0) return INT2FIX(0);
	x = rb_int2big(FIX2LONG(x));
	return rb_big_pow(x, y);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	if (RFLOAT_VALUE(y) == 0.0) return DBL2NUM(1.0);
	if (a == 0) {
	    return DBL2NUM(RFLOAT_VALUE(y) < 0 ? INFINITY : 0.0);
	}
	if (a == 1) return DBL2NUM(1.0);
	{
	    double dy = RFLOAT_VALUE(y);
	    if (a < 0 && dy != round(dy))
		return rb_funcall(rb_complex_raw1(x), idPow, 1, y);
	    return DBL2NUM(pow((double)a, dy));
	}
    }
    else {
	return rb_num_coerce_bin(x, y, idPow);
    }
}

static VALUE
rb_int_pow(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_pow(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_pow(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#==
 * Document-method: Fixnum#==
 * call-seq:
 *   int == other  ->  true or false
 *
 * Return +true+ if +int+ equals +other+ numerically.
 * Contrast this with <code>Integer#eql?</code>, which
 * requires <i>other</i> to be a <code>Integer</code>.
 *
 *   1 == 2      #=> false
 *   1 == 1.0    #=> true
 */

static VALUE
fix_equal(VALUE x, VALUE y)
{
    if (x == y) return Qtrue;
    if (FIXNUM_P(y)) return Qfalse;
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_eq(y, x);
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
        return rb_integer_float_eq(x, y);
    }
    else {
	return num_equal(x, y);
    }
}

static VALUE
int_equal(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_equal(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_eq(x, y);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#<=>
 *  call-seq:
 *     int <=> numeric  ->  -1, 0, +1 or nil
 *
 *  Comparison---Returns +-1+, +0+, ++1+ or +nil+ depending on whether +int+ is
 *  less than, equal to, or greater than +numeric+.
 *
 *  This is the basis for the tests in the Comparable module.
 *
 *  +nil+ is returned if the two values are incomparable.
 */

static VALUE
fix_cmp(VALUE x, VALUE y)
{
    if (x == y) return INT2FIX(0);
    if (FIXNUM_P(y)) {
	if (FIX2LONG(x) > FIX2LONG(y)) return INT2FIX(1);
	return INT2FIX(-1);
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	VALUE cmp = rb_big_cmp(y, x);
	switch (cmp) {
	  case INT2FIX(+1): return INT2FIX(-1);
	  case INT2FIX(-1): return INT2FIX(+1);
	}
	return cmp;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	return rb_integer_float_cmp(x, y);
    }
    else {
	return rb_num_coerce_cmp(x, y, id_cmp);
    }
    return rb_num_coerce_cmp(x, y, id_cmp);
}

static VALUE
int_cmp(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_cmp(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_cmp(x, y);
    }
    else {
	rb_raise(rb_eNotImpError, "need to define `<=>' in %s", rb_obj_classname(x));
    }
}

/*
 * Document-method: Integer#>
 * Document-method: Fixnum#>
 * call-seq:
 *   int > real  ->  true or false
 *
 * Returns +true+ if the value of +int+ is greater than that of +real+.
 */

static VALUE
fix_gt(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(x) > FIX2LONG(y)) return Qtrue;
	return Qfalse;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_cmp(y, x) == INT2FIX(-1) ? Qtrue : Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
        return rb_integer_float_cmp(x, y) == INT2FIX(1) ? Qtrue : Qfalse;
    }
    else {
	return rb_num_coerce_relop(x, y, '>');
    }
}

static VALUE
int_gt(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_gt(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_gt(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#>=
 * Document-method: Fixnum#>=
 * call-seq:
 *   int >= real  ->  true or false
 *
 * Returns +true+ if the value of +int+ is greater than or equal to that of
 * +real+.
 */

static VALUE
fix_ge(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(x) >= FIX2LONG(y)) return Qtrue;
	return Qfalse;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_cmp(y, x) != INT2FIX(+1) ? Qtrue : Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	VALUE rel = rb_integer_float_cmp(x, y);
	return rel == INT2FIX(1) || rel == INT2FIX(0) ? Qtrue : Qfalse;
    }
    else {
	return rb_num_coerce_relop(x, y, idGE);
    }
}

static VALUE
int_ge(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_ge(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_ge(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#<
 * Document-method: Fixnum#<
 * call-seq:
 *   int < real  ->  true or false
 *
 * Returns +true+ if the value of +int+ is less than that of +real+.
 */

static VALUE
fix_lt(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(x) < FIX2LONG(y)) return Qtrue;
	return Qfalse;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_cmp(y, x) == INT2FIX(+1) ? Qtrue : Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
        return rb_integer_float_cmp(x, y) == INT2FIX(-1) ? Qtrue : Qfalse;
    }
    else {
	return rb_num_coerce_relop(x, y, '<');
    }
}

static VALUE
int_lt(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_lt(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_lt(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#<=
 * Document-method: Fixnum#<=
 * call-seq:
 *   int <= real  ->  true or false
 *
 * Returns +true+ if the value of +int+ is less than or equal to that of
 * +real+.
 */

static VALUE
fix_le(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	if (FIX2LONG(x) <= FIX2LONG(y)) return Qtrue;
	return Qfalse;
    }
    else if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_cmp(y, x) != INT2FIX(-1) ? Qtrue : Qfalse;
    }
    else if (RB_TYPE_P(y, T_FLOAT)) {
	VALUE rel = rb_integer_float_cmp(x, y);
	return rel == INT2FIX(-1) || rel == INT2FIX(0) ? Qtrue : Qfalse;
    }
    else {
	return rb_num_coerce_relop(x, y, idLE);
    }
}

static VALUE
int_le(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_le(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_le(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#~
 * call-seq:
 *   ~integer  ->  integer
 *
 * One's complement: returns a number where each bit is flipped.
 *
 * Inverts the bits in a integer. As Integers are conceptually infinite
 * length, the result acts as if it had an infinite number of one
 * bits to the left. In hex representations, this is displayed
 * as two periods to the left of the digits.
 *
 *   sprintf("%X", ~0x1122334455)    #=> "..FEEDDCCBBAA"
 *
 */

static VALUE
fix_comp(VALUE num)
{
    return ~num | FIXNUM_FLAG;
}

static VALUE
int_comp(VALUE num)
{
    if (FIXNUM_P(num)) {
	return fix_comp(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_comp(num);
    }
    return Qnil;
}

static int
bit_coerce(VALUE *x, VALUE *y)
{
    if (!FIXNUM_P(*y) && !RB_TYPE_P(*y, T_BIGNUM)) {
	VALUE orig = *x;
	do_coerce(x, y, TRUE);
	if (!FIXNUM_P(*x) && !RB_TYPE_P(*x, T_BIGNUM)
	    && !FIXNUM_P(*y) && !RB_TYPE_P(*y, T_BIGNUM)) {
	    coerce_failed(orig, *y);
	}
    }
    return TRUE;
}

VALUE
rb_num_coerce_bit(VALUE x, VALUE y, ID func)
{
    bit_coerce(&x, &y);
    return rb_funcall(x, func, 1, y);
}

/*
 * Document-method: Integer#&
 * call-seq:
 *   integer & integer  ->  integer_result
 *
 * Bitwise AND.
 */

static VALUE
fix_and(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	long val = FIX2LONG(x) & FIX2LONG(y);
	return LONG2NUM(val);
    }

    if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_and(y, x);
    }

    bit_coerce(&x, &y);
    return rb_funcall(x, '&', 1, y);
}

static VALUE
int_and(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_and(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_and(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#|
 * call-seq:
 *   integer | integer  ->  integer_result
 *
 * Bitwise OR.
 */

static VALUE
fix_or(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	long val = FIX2LONG(x) | FIX2LONG(y);
	return LONG2NUM(val);
    }

    if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_or(y, x);
    }

    bit_coerce(&x, &y);
    return rb_funcall(x, '|', 1, y);
}

static VALUE
int_or(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_or(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_or(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#^
 * call-seq:
 *   integer ^ integer  ->  integer_result
 *
 * Bitwise EXCLUSIVE OR.
 */

static VALUE
fix_xor(VALUE x, VALUE y)
{
    if (FIXNUM_P(y)) {
	long val = FIX2LONG(x) ^ FIX2LONG(y);
	return LONG2NUM(val);
    }

    if (RB_TYPE_P(y, T_BIGNUM)) {
	return rb_big_xor(y, x);
    }

    bit_coerce(&x, &y);
    return rb_funcall(x, '^', 1, y);
}

static VALUE
int_xor(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return fix_xor(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_xor(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#<<
 * call-seq:
 *   int << count  ->  integer
 *
 * Shifts +int+ left +count+ positions, or right if +count+ is negative.
 */

static VALUE
rb_fix_lshift(VALUE x, VALUE y)
{
    long val, width;

    val = NUM2LONG(x);
    if (!FIXNUM_P(y))
	return rb_big_lshift(rb_int2big(val), y);
    width = FIX2LONG(y);
    if (width < 0)
	return fix_rshift(val, (unsigned long)-width);
    return fix_lshift(val, width);
}

static VALUE
fix_lshift(long val, unsigned long width)
{
    if (width > (SIZEOF_LONG*CHAR_BIT-1)
	|| ((unsigned long)val)>>(SIZEOF_LONG*CHAR_BIT-1-width) > 0) {
	return rb_big_lshift(rb_int2big(val), ULONG2NUM(width));
    }
    val = val << width;
    return LONG2NUM(val);
}

static VALUE
rb_int_lshift(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return rb_fix_lshift(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_lshift(x, y);
    }
    return Qnil;
}

/*
 * Document-method: Integer#>>
 * call-seq:
 *   int >> count  ->  integer
 *
 * Shifts +int+ right +count+ positions, or left if +count+ is negative.
 */

static VALUE
rb_fix_rshift(VALUE x, VALUE y)
{
    long i, val;

    val = FIX2LONG(x);
    if (!FIXNUM_P(y))
	return rb_big_rshift(rb_int2big(val), y);
    i = FIX2LONG(y);
    if (i == 0) return x;
    if (i < 0)
	return fix_lshift(val, (unsigned long)-i);
    return fix_rshift(val, i);
}

static VALUE
fix_rshift(long val, unsigned long i)
{
    if (i >= sizeof(long)*CHAR_BIT-1) {
	if (val < 0) return INT2FIX(-1);
	return INT2FIX(0);
    }
    val = RSHIFT(val, i);
    return LONG2FIX(val);
}

static VALUE
rb_int_rshift(VALUE x, VALUE y)
{
    if (FIXNUM_P(x)) {
	return rb_fix_rshift(x, y);
    }
    else if (RB_TYPE_P(x, T_BIGNUM)) {
	return rb_big_rshift(x, y);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#[]
 *  call-seq:
 *     int[n]  ->  0, 1
 *
 *  Bit Reference---Returns the +n+th bit in the binary representation of
 *  +int+, where <code>int[0]</code> is the least significant bit.
 *
 *  For example:
 *
 *     a = 0b11001100101010
 *     30.downto(0) do |n| print a[n] end
 *     #=> 0000000000000000011001100101010
 *
 *     a = 9**15
 *     50.downto(0) do |n|
 *       print a[n]
 *     end
 *     #=> 000101110110100000111000011110010100111100010111001
 */

static VALUE
fix_aref(VALUE fix, VALUE idx)
{
    long val = FIX2LONG(fix);
    long i;

    idx = rb_to_int(idx);
    if (!FIXNUM_P(idx)) {
	idx = rb_big_norm(idx);
	if (!FIXNUM_P(idx)) {
	    if (!BIGNUM_SIGN(idx) || val >= 0)
		return INT2FIX(0);
	    return INT2FIX(1);
	}
    }
    i = FIX2LONG(idx);

    if (i < 0) return INT2FIX(0);
    if (SIZEOF_LONG*CHAR_BIT-1 <= i) {
	if (val < 0) return INT2FIX(1);
	return INT2FIX(0);
    }
    if (val & (1L<<i))
	return INT2FIX(1);
    return INT2FIX(0);
}

static VALUE
int_aref(VALUE num, VALUE idx)
{
    if (FIXNUM_P(num)) {
	return fix_aref(num, idx);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_aref(num, idx);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#to_f
 *  call-seq:
 *     int.to_f  ->  float
 *
 *  Converts +int+ to a +Float+.  If +int+ doesn't fit in a +Float+,
 *  the result is infinity.
 *
 */

static VALUE
int_to_f(VALUE num)
{
    double val;

    if (FIXNUM_P(num)) {
	val = (double)FIX2LONG(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	val = rb_big2dbl(num);
    }
    else {
	rb_raise(rb_eNotImpError, "Unknown subclass for to_f: %s", rb_obj_classname(num));
    }

    return DBL2NUM(val);
}

/*
 *  Document-method: Integer#abs
 *  Document-method: Integer#magnitude
 *  call-seq:
 *     int.abs        ->  integer
 *     int.magnitude  ->  integer
 *
 *  Returns the absolute value of +int+.
 *
 *     -12345.abs   #=> 12345
 *     12345.abs    #=> 12345
 *     -1234567890987654321.abs   #=> 1234567890987654321
 *
 */

static VALUE
fix_abs(VALUE fix)
{
    long i = FIX2LONG(fix);

    if (i < 0) i = -i;

    return LONG2NUM(i);
}

static VALUE
int_abs(VALUE num)
{
    if (FIXNUM_P(num)) {
	return fix_abs(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_abs(num);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#size
 *  call-seq:
 *     int.size  ->  int
 *
 *  Returns the number of bytes in the machine representation of +fix+.
 *
 *     1.size            #=> 4
 *     -1.size           #=> 4
 *     2147483647.size   #=> 4
 *     (256**10 - 1).size   #=> 12
 *     (256**20 - 1).size   #=> 20
 *     (256**40 - 1).size   #=> 40
 */

static VALUE
fix_size(VALUE fix)
{
    return INT2FIX(sizeof(long));
}

static VALUE
int_size(VALUE num)
{
    if (FIXNUM_P(num)) {
	return fix_size(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_size_m(num);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#bit_length
 *  call-seq:
 *     int.bit_length -> integer
 *
 *  Returns the number of bits of the value of <i>int</i>.
 *
 *  "the number of bits" means that
 *  the bit position of the highest bit which is different to the sign bit.
 *  (The bit position of the bit 2**n is n+1.)
 *  If there is no such bit (zero or minus one), zero is returned.
 *
 *  I.e. This method returns ceil(log2(int < 0 ? -int : int+1)).
 *
 *     (-2**10000-1).bit_length  #=> 10001
 *     (-2**10000).bit_length    #=> 10000
 *     (-2**10000+1).bit_length  #=> 10000
 *     (-2**1000-1).bit_length   #=> 1001
 *     (-2**1000).bit_length     #=> 1000
 *     (-2**1000+1).bit_length   #=> 1000
 *     (-2**12-1).bit_length     #=> 13
 *     (-2**12).bit_length       #=> 12
 *     (-2**12+1).bit_length     #=> 12
 *     -0x101.bit_length         #=> 9
 *     -0x100.bit_length         #=> 8
 *     -0xff.bit_length          #=> 8
 *     -2.bit_length             #=> 1
 *     -1.bit_length             #=> 0
 *     0.bit_length              #=> 0
 *     1.bit_length              #=> 1
 *     0xff.bit_length           #=> 8
 *     0x100.bit_length          #=> 9
 *     (2**12-1).bit_length      #=> 12
 *     (2**12).bit_length        #=> 13
 *     (2**12+1).bit_length      #=> 13
 *     (2**1000-1).bit_length    #=> 1000
 *     (2**1000).bit_length      #=> 1001
 *     (2**1000+1).bit_length    #=> 1001
 *     (2**10000-1).bit_length   #=> 10000
 *     (2**10000).bit_length     #=> 10001
 *     (2**10000+1).bit_length   #=> 10001
 *
 *  This method can be used to detect overflow in Array#pack as follows.
 *
 *     if n.bit_length < 32
 *       [n].pack("l") # no overflow
 *     else
 *       raise "overflow"
 *     end
 */

static VALUE
rb_fix_bit_length(VALUE fix)
{
    long v = FIX2LONG(fix);
    if (v < 0)
        v = ~v;
    return LONG2FIX(bit_length(v));
}

static VALUE
rb_int_bit_length(VALUE num)
{
    if (FIXNUM_P(num)) {
	return rb_fix_bit_length(num);
    }
    else if (RB_TYPE_P(num, T_BIGNUM)) {
	return rb_big_bit_length(num);
    }
    return Qnil;
}

/*
 *  Document-method: Integer#upto
 *  call-seq:
 *     int.upto(limit) {|i| block }  ->  self
 *     int.upto(limit)               ->  an_enumerator
 *
 *  Iterates the given block, passing in integer values from +int+ up to and
 *  including +limit+.
 *
 *  If no block is given, an Enumerator is returned instead.
 *
 *  For example:
 *
 *     5.upto(10) { |i| print i, " " }
 *     #=> 5 6 7 8 9 10
 */

static VALUE
int_upto_size(VALUE from, VALUE args, VALUE eobj)
{
    return ruby_num_interval_step_size(from, RARRAY_AREF(args, 0), INT2FIX(1), FALSE);
}

static VALUE
int_upto(VALUE from, VALUE to)
{
    RETURN_SIZED_ENUMERATOR(from, 1, &to, int_upto_size);
    if (FIXNUM_P(from) && FIXNUM_P(to)) {
	long i, end;

	end = FIX2LONG(to);
	for (i = FIX2LONG(from); i <= end; i++) {
	    rb_yield(LONG2FIX(i));
	}
    }
    else {
	VALUE i = from, c;

	while (!(c = rb_funcall(i, '>', 1, to))) {
	    rb_yield(i);
	    i = rb_funcall(i, '+', 1, INT2FIX(1));
	}
	if (NIL_P(c)) rb_cmperr(i, to);
    }
    return from;
}

/*
 *  Document-method: Integer#downto
 *  call-seq:
 *     int.downto(limit) {|i| block }  ->  self
 *     int.downto(limit)               ->  an_enumerator
 *
 *  Iterates the given block, passing decreasing values from +int+ down to and
 *  including +limit+.
 *
 *  If no block is given, an Enumerator is returned instead.
 *
 *     5.downto(1) { |n| print n, ".. " }
 *     print "  Liftoff!\n"
 *     #=> "5.. 4.. 3.. 2.. 1..   Liftoff!"
 */

static VALUE
int_downto_size(VALUE from, VALUE args, VALUE eobj)
{
    return ruby_num_interval_step_size(from, RARRAY_AREF(args, 0), INT2FIX(-1), FALSE);
}

static VALUE
int_downto(VALUE from, VALUE to)
{
    RETURN_SIZED_ENUMERATOR(from, 1, &to, int_downto_size);
    if (FIXNUM_P(from) && FIXNUM_P(to)) {
	long i, end;

	end = FIX2LONG(to);
	for (i=FIX2LONG(from); i >= end; i--) {
	    rb_yield(LONG2FIX(i));
	}
    }
    else {
	VALUE i = from, c;

	while (!(c = rb_funcall(i, '<', 1, to))) {
	    rb_yield(i);
	    i = rb_funcall(i, '-', 1, INT2FIX(1));
	}
	if (NIL_P(c)) rb_cmperr(i, to);
    }
    return from;
}

/*
 *  Document-method: Integer#times
 *  call-seq:
 *     int.times {|i| block }  ->  self
 *     int.times               ->  an_enumerator
 *
 *  Iterates the given block +int+ times, passing in values from zero to
 *  <code>int - 1</code>.
 *
 *  If no block is given, an Enumerator is returned instead.
 *
 *     5.times do |i|
 *       print i, " "
 *     end
 *     #=> 0 1 2 3 4
 */

static VALUE
int_dotimes_size(VALUE num, VALUE args, VALUE eobj)
{
    if (FIXNUM_P(num)) {
	if (NUM2LONG(num) <= 0) return INT2FIX(0);
    }
    else {
	if (RTEST(rb_funcall(num, '<', 1, INT2FIX(0)))) return INT2FIX(0);
    }
    return num;
}

static VALUE
int_dotimes(VALUE num)
{
    RETURN_SIZED_ENUMERATOR(num, 0, 0, int_dotimes_size);

    if (FIXNUM_P(num)) {
	long i, end;

	end = FIX2LONG(num);
	for (i=0; i<end; i++) {
	    rb_yield_1(LONG2FIX(i));
	}
    }
    else {
	VALUE i = INT2FIX(0);

	for (;;) {
	    if (!RTEST(rb_funcall(i, '<', 1, num))) break;
	    rb_yield(i);
	    i = rb_funcall(i, '+', 1, INT2FIX(1));
	}
    }
    return num;
}

/*
 *  Document-method: Integer#round
 *  call-seq:
 *     int.round([ndigits])  ->  integer or float
 *
 *  Rounds +int+ to a given precision in decimal digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and round down for negative.
 *
 *     1.round        #=> 1
 *     1.round(2)     #=> 1.0
 *     15.round(-1)   #=> 20
 */

static VALUE
int_round(int argc, VALUE* argv, VALUE num)
{
    int ndigits;

    if (!rb_check_arity(argc, 0, 1)) return num;
    ndigits = NUM2INT(argv[0]);
    if (ndigits > 0) {
	return rb_Float(num);
    }
    if (ndigits == 0) {
	return num;
    }
    return rb_int_round(num, ndigits);
}

/*
 *  Document-method: Integer#floor
 *  call-seq:
 *     int.floor([ndigits])  ->  integer or float
 *
 *  Returns the largest number less than or equal to +int+ in decimal
 *  digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and floor down for negative.
 *
 *     1.floor        #=> 1
 *     1.floor(2)     #=> 1.0
 *     15.floor(-1)   #=> 10
 */

static VALUE
int_floor(int argc, VALUE* argv, VALUE num)
{
    int ndigits;

    if (!rb_check_arity(argc, 0, 1)) return num;
    ndigits = NUM2INT(argv[0]);
    if (ndigits > 0) {
	return rb_Float(num);
    }
    if (ndigits == 0) {
	return num;
    }
    return rb_int_floor(num, ndigits);
}

/*
 *  Document-method: Integer#ceil
 *  call-seq:
 *     int.ceil([ndigits])  ->  integer or float
 *
 *  Returns the smallest number than or equal to +int+ in decimal
 *  digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and ceil up for negative.
 *
 *     1.ceil        #=> 1
 *     1.ceil(2)     #=> 1.0
 *     15.ceil(-1)   #=> 20
 */

static VALUE
int_ceil(int argc, VALUE* argv, VALUE num)
{
    int ndigits;

    if (!rb_check_arity(argc, 0, 1)) return num;
    ndigits = NUM2INT(argv[0]);
    if (ndigits > 0) {
	return rb_Float(num);
    }
    if (ndigits == 0) {
	return num;
    }
    return rb_int_ceil(num, ndigits);
}

/*
 *  Document-method: Integer#truncate
 *  call-seq:
 *     int.truncate([ndigits])  ->  integer or float
 *
 *  Returns the smallest number than or equal to +int+ in decimal
 *  digits (default 0 digits).
 *
 *  Precision may be negative.  Returns a floating point number when +ndigits+
 *  is positive, +self+ for zero, and truncate up for negative.
 *
 *     1.truncate        #=> 1
 *     1.truncate(2)     #=> 1.0
 *     15.truncate(-1)   #=> 10
 */

static VALUE
int_truncate(int argc, VALUE* argv, VALUE num)
{
    int ndigits;

    if (!rb_check_arity(argc, 0, 1)) return num;
    ndigits = NUM2INT(argv[0]);
    if (ndigits > 0) {
	return rb_Float(num);
    }
    if (ndigits == 0) {
	return num;
    }
    return rb_int_truncate(num, ndigits);
}

/*
 *  Document-class: ZeroDivisionError
 *
 *  Raised when attempting to divide an integer by 0.
 *
 *     42 / 0
 *     #=> ZeroDivisionError: divided by 0
 *
 *  Note that only division by an exact 0 will raise the exception:
 *
 *     42 /  0.0 #=> Float::INFINITY
 *     42 / -0.0 #=> -Float::INFINITY
 *     0  /  0.0 #=> NaN
 */

/*
 *  Document-class: FloatDomainError
 *
 *  Raised when attempting to convert special float values (in particular
 *  +infinite+ or +NaN+) to numerical classes which don't support them.
 *
 *     Float::INFINITY.to_r
 *     #=> FloatDomainError: Infinity
 */

/*
 * Document-class: Numeric
 *
 * Numeric is the class from which all higher-level numeric classes should inherit.
 *
 * Numeric allows instantiation of heap-allocated objects. Other core numeric classes such as
 * Integer are implemented as immediates, which means that each Integer is a single immutable
 * object which is always passed by value.
 *
 *   a = 1
 *   puts 1.object_id == a.object_id   #=> true
 *
 * There can only ever be one instance of the integer +1+, for example. Ruby ensures this
 * by preventing instantiation and duplication.
 *
 *   Integer.new(1)   #=> NoMethodError: undefined method `new' for Integer:Class
 *   1.dup            #=> TypeError: can't dup Fixnum
 *
 * For this reason, Numeric should be used when defining other numeric classes.
 *
 * Classes which inherit from Numeric must implement +coerce+, which returns a two-member
 * Array containing an object that has been coerced into an instance of the new class
 * and +self+ (see #coerce).
 *
 * Inheriting classes should also implement arithmetic operator methods (<code>+</code>,
 * <code>-</code>, <code>*</code> and <code>/</code>) and the <code><=></code> operator (see
 * Comparable). These methods may rely on +coerce+ to ensure interoperability with
 * instances of other numeric classes.
 *
 *   class Tally < Numeric
 *     def initialize(string)
 *       @string = string
 *     end
 *
 *     def to_s
 *       @string
 *     end
 *
 *     def to_i
 *       @string.size
 *     end
 *
 *     def coerce(other)
 *       [self.class.new('|' * other.to_i), self]
 *     end
 *
 *     def <=>(other)
 *       to_i <=> other.to_i
 *     end
 *
 *     def +(other)
 *       self.class.new('|' * (to_i + other.to_i))
 *     end
 *
 *     def -(other)
 *       self.class.new('|' * (to_i - other.to_i))
 *     end
 *
 *     def *(other)
 *       self.class.new('|' * (to_i * other.to_i))
 *     end
 *
 *     def /(other)
 *       self.class.new('|' * (to_i / other.to_i))
 *     end
 *   end
 *
 *   tally = Tally.new('||')
 *   puts tally * 2            #=> "||||"
 *   puts tally > 1            #=> true
 */
void
Init_Numeric(void)
{
#undef rb_intern
#define rb_intern(str) rb_intern_const(str)

#if defined(__FreeBSD__) && __FreeBSD__ < 4
    /* allow divide by zero -- Inf */
    fpsetmask(fpgetmask() & ~(FP_X_DZ|FP_X_INV|FP_X_OFL));
#elif defined(_UNICOSMP)
    /* Turn off floating point exceptions for divide by zero, etc. */
    _set_Creg(0, 0);
#endif
    id_coerce = rb_intern("coerce");
    id_div = rb_intern("div");
    id_divmod = rb_intern("divmod");

    rb_eZeroDivError = rb_define_class("ZeroDivisionError", rb_eStandardError);
    rb_eFloatDomainError = rb_define_class("FloatDomainError", rb_eRangeError);
    rb_cNumeric = rb_define_class("Numeric", rb_cObject);

    rb_define_method(rb_cNumeric, "singleton_method_added", num_sadded, 1);
    rb_include_module(rb_cNumeric, rb_mComparable);
    rb_define_method(rb_cNumeric, "initialize_copy", num_init_copy, 1);
    rb_define_method(rb_cNumeric, "coerce", num_coerce, 1);

    rb_define_method(rb_cNumeric, "i", num_imaginary, 0);
    rb_define_method(rb_cNumeric, "+@", num_uplus, 0);
    rb_define_method(rb_cNumeric, "-@", num_uminus, 0);
    rb_define_method(rb_cNumeric, "<=>", num_cmp, 1);
    rb_define_method(rb_cNumeric, "eql?", num_eql, 1);
    rb_define_method(rb_cNumeric, "fdiv", num_fdiv, 1);
    rb_define_method(rb_cNumeric, "div", num_div, 1);
    rb_define_method(rb_cNumeric, "divmod", num_divmod, 1);
    rb_define_method(rb_cNumeric, "%", num_modulo, 1);
    rb_define_method(rb_cNumeric, "modulo", num_modulo, 1);
    rb_define_method(rb_cNumeric, "remainder", num_remainder, 1);
    rb_define_method(rb_cNumeric, "abs", num_abs, 0);
    rb_define_method(rb_cNumeric, "magnitude", num_abs, 0);
    rb_define_method(rb_cNumeric, "to_int", num_to_int, 0);

    rb_define_method(rb_cNumeric, "real?", num_real_p, 0);
    rb_define_method(rb_cNumeric, "integer?", num_int_p, 0);
    rb_define_method(rb_cNumeric, "zero?", num_zero_p, 0);
    rb_define_method(rb_cNumeric, "nonzero?", num_nonzero_p, 0);

    rb_define_method(rb_cNumeric, "floor", num_floor, -1);
    rb_define_method(rb_cNumeric, "ceil", num_ceil, -1);
    rb_define_method(rb_cNumeric, "round", num_round, -1);
    rb_define_method(rb_cNumeric, "truncate", num_truncate, -1);
    rb_define_method(rb_cNumeric, "step", num_step, -1);
    rb_define_method(rb_cNumeric, "positive?", num_positive_p, 0);
    rb_define_method(rb_cNumeric, "negative?", num_negative_p, 0);

    rb_cInteger = rb_define_class("Integer", rb_cNumeric);
    rb_undef_alloc_func(rb_cInteger);
    rb_undef_method(CLASS_OF(rb_cInteger), "new");

    rb_define_method(rb_cInteger, "to_s", int_to_s, -1);
    rb_define_alias(rb_cInteger, "inspect", "to_s");
    rb_define_method(rb_cInteger, "integer?", int_int_p, 0);
    rb_define_method(rb_cInteger, "odd?", int_odd_p, 0);
    rb_define_method(rb_cInteger, "even?", int_even_p, 0);
    rb_define_method(rb_cInteger, "upto", int_upto, 1);
    rb_define_method(rb_cInteger, "downto", int_downto, 1);
    rb_define_method(rb_cInteger, "times", int_dotimes, 0);
    rb_define_method(rb_cInteger, "succ", int_succ, 0);
    rb_define_method(rb_cInteger, "next", int_succ, 0);
    rb_define_method(rb_cInteger, "pred", int_pred, 0);
    rb_define_method(rb_cInteger, "chr", int_chr, -1);
    rb_define_method(rb_cInteger, "ord", int_ord, 0);
    rb_define_method(rb_cInteger, "to_i", int_to_i, 0);
    rb_define_method(rb_cInteger, "to_int", int_to_i, 0);
    rb_define_method(rb_cInteger, "to_f", int_to_f, 0);
    rb_define_method(rb_cInteger, "floor", int_floor, -1);
    rb_define_method(rb_cInteger, "ceil", int_ceil, -1);
    rb_define_method(rb_cInteger, "truncate", int_truncate, -1);
    rb_define_method(rb_cInteger, "round", int_round, -1);
    rb_define_method(rb_cInteger, "<=>", int_cmp, 1);

    rb_define_method(rb_cInteger, "-@", rb_int_uminus, 0);
    rb_define_method(rb_cInteger, "+", rb_int_plus, 1);
    rb_define_method(rb_cInteger, "-", rb_int_minus, 1);
    rb_define_method(rb_cInteger, "*", rb_int_mul, 1);
    rb_define_method(rb_cInteger, "/", rb_int_div, 1);
    rb_define_method(rb_cInteger, "div", rb_int_idiv, 1);
    rb_define_method(rb_cInteger, "%", rb_int_modulo, 1);
    rb_define_method(rb_cInteger, "modulo", rb_int_modulo, 1);
    rb_define_method(rb_cInteger, "remainder", int_remainder, 1);
    rb_define_method(rb_cInteger, "divmod", int_divmod, 1);
    rb_define_method(rb_cInteger, "fdiv", int_fdiv, 1);
    rb_define_method(rb_cInteger, "**", rb_int_pow, 1);

    rb_define_method(rb_cInteger, "abs", int_abs, 0);
    rb_define_method(rb_cInteger, "magnitude", int_abs, 0);

    rb_define_method(rb_cInteger, "==", int_equal, 1);
    rb_define_method(rb_cInteger, ">", int_gt, 1);
    rb_define_method(rb_cInteger, ">=", int_ge, 1);
    rb_define_method(rb_cInteger, "<", int_lt, 1);
    rb_define_method(rb_cInteger, "<=", int_le, 1);

    rb_define_method(rb_cInteger, "~", int_comp, 0);
    rb_define_method(rb_cInteger, "&", int_and, 1);
    rb_define_method(rb_cInteger, "|", int_or,  1);
    rb_define_method(rb_cInteger, "^", int_xor, 1);
    rb_define_method(rb_cInteger, "[]", int_aref, 1);

    rb_define_method(rb_cInteger, "<<", rb_int_lshift, 1);
    rb_define_method(rb_cInteger, ">>", rb_int_rshift, 1);

    rb_define_method(rb_cInteger, "size", int_size, 0);
    rb_define_method(rb_cInteger, "bit_length", rb_int_bit_length, 0);

    rb_cFixnum = rb_define_class("Fixnum", rb_cInteger);

    rb_define_method(rb_cFixnum, "+", fix_plus, 1);
    rb_define_method(rb_cFixnum, "-", fix_minus, 1);
    rb_define_method(rb_cFixnum, "*", fix_mul, 1);
    rb_define_method(rb_cFixnum, "/", fix_div, 1);
    rb_define_method(rb_cFixnum, "%", fix_mod, 1);

    rb_define_method(rb_cFixnum, "==", fix_equal, 1);
    rb_define_method(rb_cFixnum, "===", fix_equal, 1);
    rb_define_method(rb_cFixnum, ">",  fix_gt, 1);
    rb_define_method(rb_cFixnum, ">=", fix_ge, 1);
    rb_define_method(rb_cFixnum, "<",  fix_lt, 1);
    rb_define_method(rb_cFixnum, "<=", fix_le, 1);

    rb_define_method(rb_cFixnum, "succ", fix_succ, 0);

    rb_cFloat  = rb_define_class("Float", rb_cNumeric);

    rb_undef_alloc_func(rb_cFloat);
    rb_undef_method(CLASS_OF(rb_cFloat), "new");

    /*
     *  Represents the rounding mode for floating point addition.
     *
     *  Usually defaults to 1, rounding to the nearest number.
     *
     *  Other modes include:
     *
     *  -1::	Indeterminable
     *	0::	Rounding towards zero
     *	1::	Rounding to the nearest number
     *	2::	Rounding towards positive infinity
     *	3::	Rounding towards negative infinity
     */
    rb_define_const(rb_cFloat, "ROUNDS", INT2FIX(FLT_ROUNDS));
    /*
     *	The base of the floating point, or number of unique digits used to
     *	represent the number.
     *
     *  Usually defaults to 2 on most systems, which would represent a base-10 decimal.
     */
    rb_define_const(rb_cFloat, "RADIX", INT2FIX(FLT_RADIX));
    /*
     * The number of base digits for the +double+ data type.
     *
     * Usually defaults to 53.
     */
    rb_define_const(rb_cFloat, "MANT_DIG", INT2FIX(DBL_MANT_DIG));
    /*
     *	The minimum number of significant decimal digits in a double-precision
     *	floating point.
     *
     *	Usually defaults to 15.
     */
    rb_define_const(rb_cFloat, "DIG", INT2FIX(DBL_DIG));
    /*
     *	The smallest posable exponent value in a double-precision floating
     *	point.
     *
     *	Usually defaults to -1021.
     */
    rb_define_const(rb_cFloat, "MIN_EXP", INT2FIX(DBL_MIN_EXP));
    /*
     *	The largest possible exponent value in a double-precision floating
     *	point.
     *
     *	Usually defaults to 1024.
     */
    rb_define_const(rb_cFloat, "MAX_EXP", INT2FIX(DBL_MAX_EXP));
    /*
     *	The smallest negative exponent in a double-precision floating point
     *	where 10 raised to this power minus 1.
     *
     *	Usually defaults to -307.
     */
    rb_define_const(rb_cFloat, "MIN_10_EXP", INT2FIX(DBL_MIN_10_EXP));
    /*
     *	The largest positive exponent in a double-precision floating point where
     *	10 raised to this power minus 1.
     *
     *	Usually defaults to 308.
     */
    rb_define_const(rb_cFloat, "MAX_10_EXP", INT2FIX(DBL_MAX_10_EXP));
    /*
     *	The smallest positive normalized number in a double-precision floating point.
     *
     *	Usually defaults to 2.2250738585072014e-308.
     *
     *	If the platform supports denormalized numbers,
     *	there are numbers between zero and Float::MIN.
     *	0.0.next_float returns the smallest positive floating point number
     *	including denormalized numbers.
     */
    rb_define_const(rb_cFloat, "MIN", DBL2NUM(DBL_MIN));
    /*
     *	The largest possible integer in a double-precision floating point number.
     *
     *	Usually defaults to 1.7976931348623157e+308.
     */
    rb_define_const(rb_cFloat, "MAX", DBL2NUM(DBL_MAX));
    /*
     *	The difference between 1 and the smallest double-precision floating
     *	point number greater than 1.
     *
     *	Usually defaults to 2.2204460492503131e-16.
     */
    rb_define_const(rb_cFloat, "EPSILON", DBL2NUM(DBL_EPSILON));
    /*
     *	An expression representing positive infinity.
     */
    rb_define_const(rb_cFloat, "INFINITY", DBL2NUM(INFINITY));
    /*
     *	An expression representing a value which is "not a number".
     */
    rb_define_const(rb_cFloat, "NAN", DBL2NUM(NAN));

    rb_define_method(rb_cFloat, "to_s", flo_to_s, 0);
    rb_define_alias(rb_cFloat, "inspect", "to_s");
    rb_define_method(rb_cFloat, "coerce", flo_coerce, 1);
    rb_define_method(rb_cFloat, "-@", flo_uminus, 0);
    rb_define_method(rb_cFloat, "+", flo_plus, 1);
    rb_define_method(rb_cFloat, "-", flo_minus, 1);
    rb_define_method(rb_cFloat, "*", flo_mul, 1);
    rb_define_method(rb_cFloat, "/", flo_div, 1);
    rb_define_method(rb_cFloat, "quo", flo_quo, 1);
    rb_define_method(rb_cFloat, "fdiv", flo_quo, 1);
    rb_define_method(rb_cFloat, "%", flo_mod, 1);
    rb_define_method(rb_cFloat, "modulo", flo_mod, 1);
    rb_define_method(rb_cFloat, "divmod", flo_divmod, 1);
    rb_define_method(rb_cFloat, "**", flo_pow, 1);
    rb_define_method(rb_cFloat, "==", flo_eq, 1);
    rb_define_method(rb_cFloat, "===", flo_eq, 1);
    rb_define_method(rb_cFloat, "<=>", flo_cmp, 1);
    rb_define_method(rb_cFloat, ">",  flo_gt, 1);
    rb_define_method(rb_cFloat, ">=", flo_ge, 1);
    rb_define_method(rb_cFloat, "<",  flo_lt, 1);
    rb_define_method(rb_cFloat, "<=", flo_le, 1);
    rb_define_method(rb_cFloat, "eql?", flo_eql, 1);
    rb_define_method(rb_cFloat, "hash", flo_hash, 0);
    rb_define_method(rb_cFloat, "to_f", flo_to_f, 0);
    rb_define_method(rb_cFloat, "abs", flo_abs, 0);
    rb_define_method(rb_cFloat, "magnitude", flo_abs, 0);
    rb_define_method(rb_cFloat, "zero?", flo_zero_p, 0);

    rb_define_method(rb_cFloat, "to_i", flo_to_i, 0);
    rb_define_method(rb_cFloat, "to_int", flo_to_i, 0);
    rb_define_method(rb_cFloat, "floor", flo_floor, -1);
    rb_define_method(rb_cFloat, "ceil", flo_ceil, -1);
    rb_define_method(rb_cFloat, "round", flo_round, -1);
    rb_define_method(rb_cFloat, "truncate", flo_truncate, -1);

    rb_define_method(rb_cFloat, "nan?",      flo_is_nan_p, 0);
    rb_define_method(rb_cFloat, "infinite?", flo_is_infinite_p, 0);
    rb_define_method(rb_cFloat, "finite?",   flo_is_finite_p, 0);
    rb_define_method(rb_cFloat, "next_float", flo_next_float, 0);
    rb_define_method(rb_cFloat, "prev_float", flo_prev_float, 0);
    rb_define_method(rb_cFloat, "positive?", flo_positive_p, 0);
    rb_define_method(rb_cFloat, "negative?", flo_negative_p, 0);

    id_to = rb_intern("to");
    id_by = rb_intern("by");
}

#undef rb_float_value
double
rb_float_value(VALUE v)
{
    return rb_float_value_inline(v);
}

#undef rb_float_new
VALUE
rb_float_new(double d)
{
    return rb_float_new_inline(d);
}