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* math.c (math_log): Support bignums bigger than 2**1024.

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(math_log2): Ditto.
  (math_log10): Ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
akr 2013-09-07 11:26:52 +00:00
parent 66915c5077
commit 08e3cb6959
2 changed files with 34 additions and 0 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
Sat Sep 7 20:25:47 2013 Tanaka Akira <akr@fsij.org>
* math.c (math_log): Support bignums bigger than 2**1024.
(math_log2): Ditto.
(math_log10): Ditto.
Sat Sep 7 15:36:00 2013 Charlie Somerville <charliesome@ruby-lang.org> Sat Sep 7 15:36:00 2013 Charlie Somerville <charliesome@ruby-lang.org>
* vm_eval.c (vm_call0): fix prototype, the id parameter should be of * vm_eval.c (vm_call0): fix prototype, the id parameter should be of

28
math.c
View File

@ -11,6 +11,7 @@
#include "ruby/ruby.h" #include "ruby/ruby.h"
#include "internal.h" #include "internal.h"
#include <float.h>
#include <math.h> #include <math.h>
#include <errno.h> #include <errno.h>
@ -439,8 +440,16 @@ math_log(int argc, VALUE *argv)
{ {
VALUE x, base; VALUE x, base;
double d0, d; double d0, d;
size_t numbits = 0;
rb_scan_args(argc, argv, "11", &x, &base); rb_scan_args(argc, argv, "11", &x, &base);
if (TYPE(x) == T_BIGNUM &&
DBL_MAX_EXP <= (numbits = rb_absint_numwords(x, 1, NULL))) {
numbits -= DBL_MANT_DIG;
x = rb_big_rshift(x, SIZET2NUM(numbits));
}
Need_Float(x); Need_Float(x);
d0 = RFLOAT_VALUE(x); d0 = RFLOAT_VALUE(x);
/* check for domain error */ /* check for domain error */
@ -448,6 +457,8 @@ math_log(int argc, VALUE *argv)
/* check for pole error */ /* check for pole error */
if (d0 == 0.0) return DBL2NUM(-INFINITY); if (d0 == 0.0) return DBL2NUM(-INFINITY);
d = log(d0); d = log(d0);
if (numbits)
d += numbits * log(2); /* log(2**numbits) */
if (argc == 2) { if (argc == 2) {
Need_Float(base); Need_Float(base);
d /= log(RFLOAT_VALUE(base)); d /= log(RFLOAT_VALUE(base));
@ -488,6 +499,13 @@ static VALUE
math_log2(VALUE obj, VALUE x) math_log2(VALUE obj, VALUE x)
{ {
double d0, d; double d0, d;
size_t numbits = 0;
if (TYPE(x) == T_BIGNUM &&
DBL_MAX_EXP <= (numbits = rb_absint_numwords(x, 1, NULL))) {
numbits -= DBL_MANT_DIG;
x = rb_big_rshift(x, SIZET2NUM(numbits));
}
Need_Float(x); Need_Float(x);
d0 = RFLOAT_VALUE(x); d0 = RFLOAT_VALUE(x);
@ -496,6 +514,7 @@ math_log2(VALUE obj, VALUE x)
/* check for pole error */ /* check for pole error */
if (d0 == 0.0) return DBL2NUM(-INFINITY); if (d0 == 0.0) return DBL2NUM(-INFINITY);
d = log2(d0); d = log2(d0);
d += numbits;
return DBL2NUM(d); return DBL2NUM(d);
} }
@ -519,6 +538,13 @@ static VALUE
math_log10(VALUE obj, VALUE x) math_log10(VALUE obj, VALUE x)
{ {
double d0, d; double d0, d;
size_t numbits = 0;
if (TYPE(x) == T_BIGNUM &&
DBL_MAX_EXP <= (numbits = rb_absint_numwords(x, 1, NULL))) {
numbits -= DBL_MANT_DIG;
x = rb_big_rshift(x, SIZET2NUM(numbits));
}
Need_Float(x); Need_Float(x);
d0 = RFLOAT_VALUE(x); d0 = RFLOAT_VALUE(x);
@ -527,6 +553,8 @@ math_log10(VALUE obj, VALUE x)
/* check for pole error */ /* check for pole error */
if (d0 == 0.0) return DBL2NUM(-INFINITY); if (d0 == 0.0) return DBL2NUM(-INFINITY);
d = log10(d0); d = log10(d0);
if (numbits)
d += numbits * log10(2); /* log10(2**numbits) */
return DBL2NUM(d); return DBL2NUM(d);
} }