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author | Lorry Tar Creator <lorry-tar-importer@baserock.org> | 2013-03-14 05:42:27 +0000 |
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committer | <> | 2013-04-03 16:25:08 +0000 |
commit | c4dd7a1a684490673e25aaf4fabec5df138854c4 (patch) | |
tree | 4d57c44caae4480efff02b90b9be86f44bf25409 /ext/bcmath/libbcmath/src/raise.c | |
download | php2-master.tar.gz |
Imported from /home/lorry/working-area/delta_php2/php-5.4.13.tar.bz2.HEADphp-5.4.13master
Diffstat (limited to 'ext/bcmath/libbcmath/src/raise.c')
-rw-r--r-- | ext/bcmath/libbcmath/src/raise.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/ext/bcmath/libbcmath/src/raise.c b/ext/bcmath/libbcmath/src/raise.c new file mode 100644 index 0000000..f2f4f4a --- /dev/null +++ b/ext/bcmath/libbcmath/src/raise.c @@ -0,0 +1,124 @@ +/* raise.c: bcmath library file. */ +/* + Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc. + Copyright (C) 2000 Philip A. Nelson + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. (COPYING.LIB) + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to: + + The Free Software Foundation, Inc. + 59 Temple Place, Suite 330 + Boston, MA 02111-1307 USA. + + You may contact the author by: + e-mail: philnelson@acm.org + us-mail: Philip A. Nelson + Computer Science Department, 9062 + Western Washington University + Bellingham, WA 98226-9062 + +*************************************************************************/ + +#include <config.h> +#include <stdio.h> +#include <assert.h> +#include <stdlib.h> +#include <ctype.h> +#include <stdarg.h> +#include "bcmath.h" +#include "private.h" + + +/* Raise NUM1 to the NUM2 power. The result is placed in RESULT. + Maximum exponent is LONG_MAX. If a NUM2 is not an integer, + only the integer part is used. */ + +void +bc_raise (bc_num num1, bc_num num2, bc_num *result, int scale TSRMLS_DC) +{ + bc_num temp, power; + long exponent; + int rscale; + int pwrscale; + int calcscale; + char neg; + + /* Check the exponent for scale digits and convert to a long. */ + if (num2->n_scale != 0) + bc_rt_warn ("non-zero scale in exponent"); + exponent = bc_num2long (num2); + if (exponent == 0 && (num2->n_len > 1 || num2->n_value[0] != 0)) + bc_rt_error ("exponent too large in raise"); + + /* Special case if exponent is a zero. */ + if (exponent == 0) + { + bc_free_num (result); + *result = bc_copy_num (BCG(_one_)); + return; + } + + /* Other initializations. */ + if (exponent < 0) + { + neg = TRUE; + exponent = -exponent; + rscale = scale; + } + else + { + neg = FALSE; + rscale = MIN (num1->n_scale*exponent, MAX(scale, num1->n_scale)); + } + + /* Set initial value of temp. */ + power = bc_copy_num (num1); + pwrscale = num1->n_scale; + while ((exponent & 1) == 0) + { + pwrscale = 2*pwrscale; + bc_multiply (power, power, &power, pwrscale TSRMLS_CC); + exponent = exponent >> 1; + } + temp = bc_copy_num (power); + calcscale = pwrscale; + exponent = exponent >> 1; + + /* Do the calculation. */ + while (exponent > 0) + { + pwrscale = 2*pwrscale; + bc_multiply (power, power, &power, pwrscale TSRMLS_CC); + if ((exponent & 1) == 1) { + calcscale = pwrscale + calcscale; + bc_multiply (temp, power, &temp, calcscale TSRMLS_CC); + } + exponent = exponent >> 1; + } + + /* Assign the value. */ + if (neg) + { + bc_divide (BCG(_one_), temp, result, rscale TSRMLS_CC); + bc_free_num (&temp); + } + else + { + bc_free_num (result); + *result = temp; + if ((*result)->n_scale > rscale) + (*result)->n_scale = rscale; + } + bc_free_num (&power); +} + |