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

  acosh.c -

  $Author$
  $Date$
  created at: Fri Apr 12 00:34:17 JST 2002

  public domain rewrite of acosh(3), asinh(3) and atanh(3)

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

#include <errno.h>
#include <float.h>
#include <math.h>

/* DBL_MANT_DIG must be less than 4 times of bits of int */
#ifndef DBL_MANT_DIG
#define DBL_MANT_DIG 53		/* in this case, at least 12 digit precision */
#endif
#define BIG_CRITERIA_BIT (1<<DBL_MANT_DIG/2)
#if BIG_CRITERIA_BIT > 0
#define BIG_CRITERIA (1.0*BIG_CRITERIA_BIT)
#else
#define BIG_CRITERIA (1.0*(1<<DBL_MANT_DIG/4)*(1<<(DBL_MANT_DIG/2+1-DBL_MANT_DIG/4)))
#endif
#define SMALL_CRITERIA_BIT (1<<(DBL_MANT_DIG/3))
#if SMALL_CRITERIA_BIT > 0
#define SMALL_CRITERIA (1.0/SMALL_CRITERIA_BIT)
#else
#define SMALL_CRITERIA (1.0*(1<<DBL_MANT_DIG/4)*(1<<(DBL_MANT_DIG/3+1-DBL_MANT_DIG/4)))
#endif

#ifndef HAVE_ACOSH
double
acosh(x)
    double x;
{
    if (x < 1)
	x = -1;			/* NaN */
    else if (x == 1)
	return 0;
    else if (x > BIG_CRITERIA)
	x += x;
    else
	x += sqrt((x + 1) * (x - 1));
    return log(x);
}
#endif

#ifndef HAVE_ASINH
double
asinh(x)
    double x;
{
    int neg = x < 0;
    double z = fabs(x);

    if (z < SMALL_CRITERIA) return x;
    if (z < (1.0/(1<<DBL_MANT_DIG/5))) {
	double x2 = z * z;
	z *= 1 + x2 * (-1.0/6.0 + x2 * 3.0/40.0);
    }
    else if (z > BIG_CRITERIA) {
	z = log(z + z);
    }
    else {
	z = log(z + sqrt(z * z + 1));
    }
    if (neg) z = -z;
    return z;
}
#endif

#ifndef HAVE_ATANH
double
atanh(x)
    double x;
{
    int neg = x < 0;
    double z = fabs(x);

    if (z < SMALL_CRITERIA) return x;
    z = log(z > 1 ? -1 : (1 + z) / (1 - z)) / 2;
    if (neg) z = -z;
    return z;
}
#endif
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<tr><td class='sub'>The Ruby Programming Language</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/ruby.git/log/?id=2b02ffa985d3b6419b91f3bae9bd22bc89fb7dc9'>root</a>/<a href='/ruby.git/log/enc?id=2b02ffa985d3b6419b91f3bae9bd22bc89fb7dc9'>enc</a>/<a href='/ruby.git/log/enc/unicode.c?id=2b02ffa985d3b6419b91f3bae9bd22bc89fb7dc9'>unicode.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/ruby.git/log/enc/unicode.c?id=2b02ffa985d3b6419b91f3bae9bd22bc89fb7dc9&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2016-01-17 11:10:45 +0000'>2016-01-17</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=f307d1fe21371ee27436da79d240ad9ade285257'>* enc/unicode.c: Fixed a logical error and some comments.</a></td><td>duerst</td></tr>
<tr><td><span title='2016-01-17 09:03:11 +0000'>2016-01-17</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=39f44f0113d3051f7d589414d0877d8dfda669b8'>get rid of non-ascii chars</a></td><td>nobu</td></tr>
<tr><td><span title='2016-01-17 08:42:16 +0000'>2016-01-17</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=959bbb6f7202676f2da1ef5e134e6152e8613b54'>* enc/unicode.c: Removed artificial expansion for Turkic,</a></td><td>duerst</td></tr>
<tr><td><span title='2016-01-16 08:24:58 +0000'>2016-01-16</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=c12af76763a1bff53ed77bc4d236f441d8679880'>* enc/unicode.c: Artificial mapping to test buffer expansion code.</a></td><td>duerst</td></tr>
<tr><td><span title='2016-01-16 01:51:58 +0000'>2016-01-16</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=219467abde26543b8cab55a95db2c03c33cfc241'>* enc/unicode.c: fix implicit conversion error with clang. fixup r53548.</a></td><td>hsbt</td></tr>
<tr><td><span title='2016-01-16 01:24:03 +0000'>2016-01-16</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=be897c2507a9d7710f218ccf377e6ea67d6d47bf'>* string.c, enc/unicode.c: New code path as a preparation for Unicode-wide</a></td><td>duerst</td></tr>
<tr><td><span title='2015-11-26 08:31:27 +0000'>2015-11-26</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=9ed1d63f41e67b1a2c50171ba9fc99a9b90e93c4'>* regcomp.c, regenc.c, regexec.c, regint.h, enc/unicode.c:</a></td><td>naruse</td></tr>
<tr><td><span title='2015-08-27 19:50:23 +0000'>2015-08-27</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=c56dd7fd0560d9c5cb3375f0ebfb5e87e534b2f5'>unicode.c: no st.h</a></td><td>nobu</td></tr>
<tr><td><span title='2015-08-27 19:49:45 +0000'>2015-08-27</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=8b9ad9d6f021cb5a7ebfba60dd258521955a202a'>oniguruma.h: constify</a></td><td>nobu</td></tr>
<tr><td><span title='2014-09-15 16:18:41 +0000'>2014-09-15</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=d2a5354255bab4d74c710ee8ff21f43998f33095'>* reg*.c: Merge Onigmo 5.15.0 38a870960aa7370051a3544</a></td><td>naruse</td></tr>
<tr><td><span title='2014-06-01 22:06:11 +0000'>2014-06-01</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=046831094b355d8d293d22a3ad5be5332307c96c'>constify rb_encoding and OnigEncoding</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:58:34 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=dd20f90408c6664766f57fa3014839237d84cdf1'>unicode.c: no initialization</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:58:24 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=7e67b396793e3c039fabc6507beddc315610c33c'>case-folding.rb: perfect hash for case unfolding3</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:58:14 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=8f598676510e1c468a8c71e21f95721592857038'>case-folding.rb: perfect hash for case unfolding2</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:58:01 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=35348a080631d9cc06e38972e2752ecc64c1eede'>case-folding.rb: perfect hash for case unfolding1</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:57:45 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=c39e659263b9a988c39ff97aca3ffde9a482e4e4'>case-folding.rb: perfect hash for case folding</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-30 23:56:00 +0000'>2014-05-30</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=88eae35862f3b228443f116234cbf09057c361c8'>case-folding.rb: merge tables</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-23 04:44:15 +0000'>2014-05-23</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=90fb7538f8247b76c9b7ce36eb13209257d863b5'>enc/unicode.c: lookup functions</a></td><td>nobu</td></tr>
<tr><td><span title='2014-05-23 04:37:02 +0000'>2014-05-23</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=dcaf699ee9cecab846637489cae5ec2f184e4cdb'>enc/unicode.c: constify</a></td><td>nobu</td></tr>
<tr><td><span title='2012-02-29 16:29:06 +0000'>2012-02-29</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=291fa223cfb2349c5e7fc5bb0e7729a2cfcc52cf'>* regparse.c (is_onechar_cclass): optimize character class</a></td><td>naruse</td></tr>
<tr><td><span title='2012-02-17 07:42:23 +0000'>2012-02-17</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=0424e152c684a85f4b0691f1e84aec203115333d'>* Merge Onigmo-5.13.1. [ruby-dev:45057] [Feature #5820]</a></td><td>naruse</td></tr>
<tr><td><span title='2011-11-20 13:44:11 +0000'>2011-11-20</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=be276c140d26d7205e5f36922d08b0b9ebd24ccc'>* enc/unicode.c (PROPERTY_NAME_MAX_SIZE): +1.</a></td><td>naruse</td></tr>
<tr><td><span title='2011-05-15 11:55:52 +0000'>2011-05-15</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=3a47cf3395dd4c4fe8bdd5df13aab698f2ca314b'>* remove trailing spaces.</a></td><td>nobu</td></tr>
<tr><td><span title='2010-10-03 22:57:23 +0000'>2010-10-03</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=e1d5d4e7f2dce151a2e768d0e2cea38f88185958'>* enc/unicode.c (onigenc_unicode_property_name_to_ctype):</a></td><td>naruse</td></tr>
<tr><td><span title='2010-03-01 21:54:59 +0000'>2010-03-01</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=db37773e13fba8ccb28612361220638e702d4deb'>* include/ruby/oniguruma.h: updated to follow Oniguruma 5.9.2.</a></td><td>matz</td></tr>
<tr><td><span title='2009-09-10 22:54:01 +0000'>2009-09-10</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=ee4b59a4191ecabc1a9d396e234f20be5e5e9f8c'>* unicode.c (onigenc_unicode_property_name_to_ctype):</a></td><td>naruse</td></tr>
<tr><td><span title='2009-09-08 13:10:04 +0000'>2009-09-08</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=31b7ae00c05aef76416c767df92be45d62e9d06a'>* include/ruby/st.h (st_hash_func): use st_index_t.</a></td><td>nobu</td></tr>
<tr><td><span title='2009-08-26 17:01:10 +0000'>2009-08-26</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=6e6a28183ac0732fa2b31d54bb69222c5d152573'>* unicode.c (PROPERTY_NAME_MAX_SIZE): use MAX_WORD_LENGTH.</a></td><td>naruse</td></tr>
<tr><td><span title='2009-08-26 00:48:49 +0000'>2009-08-26</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=1af43ae867807010d1fc37b440cbc79215de34b9'>* enc/unicode.c (onigenc_unicode_mbc_case_fold): balanced braces.</a></td><td>nobu</td></tr>
<tr><td><span title='2009-08-25 16:15:38 +0000'>2009-08-25</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=f1eff957452f55c7382beee92fd11b979a61e101'>Update Oniguruma's UnicodeData to 5.1.</a></td><td>naruse</td></tr>
<tr><td><span title='2009-08-21 08:01:09 +0000'>2009-08-21</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=a7b920686af51c7f54a2b1bd9e53c657db41d360'>* enc/unicode/name2ctype.h: split from enc/unicode.c and made a</a></td><td>nobu</td></tr>
<tr><td><span title='2009-08-19 02:32:49 +0000'>2009-08-19</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=e1c9ac6bd91e9a96e40077cc16afa1fcabc8436f'>* enc/unicode.c (CodeRanges): initialized statically.</a></td><td>nobu</td></tr>
<tr><td><span title='2008-09-18 12:53:25 +0000'>2008-09-18</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=081c802cb9fe84d349bc4ecf26a36eceae431aed'>* grapheme cluster implementation reverted.  [ruby-dev:36375]</a></td><td>akr</td></tr>
<tr><td><span title='2008-09-16 16:48:05 +0000'>2008-09-16</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=a67d4fa01c43124048be957f7d8e4090b7255393'>* include/ruby/oniguruma.h (OnigEncodingTypeST): add precise_ret</a></td><td>akr</td></tr>
<tr><td><span title='2008-06-17 13:06:34 +0000'>2008-06-17</span></td><td><a href='/ruby.git/commit/enc/unicode.c?id=d7baa40cac61f9d3af3c5a8b615ca0dd303cb8c2'>* enc/euc_jp.c (property_name_to_ctype): core dumped when sizeof(int)</a></td><td>mame</td></tr>