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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/div.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/div.c')
-rw-r--r-- | ext/bcmath/libbcmath/src/div.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/ext/bcmath/libbcmath/src/div.c b/ext/bcmath/libbcmath/src/div.c new file mode 100644 index 0000000..8c05170 --- /dev/null +++ b/ext/bcmath/libbcmath/src/div.c @@ -0,0 +1,274 @@ +/* div.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" + + +/* Some utility routines for the divide: First a one digit multiply. + NUM (with SIZE digits) is multiplied by DIGIT and the result is + placed into RESULT. It is written so that NUM and RESULT can be + the same pointers. */ + +static void +_one_mult (num, size, digit, result) + unsigned char *num; + int size, digit; + unsigned char *result; +{ + int carry, value; + unsigned char *nptr, *rptr; + + if (digit == 0) + memset (result, 0, size); + else + { + if (digit == 1) + memcpy (result, num, size); + else + { + /* Initialize */ + nptr = (unsigned char *) (num+size-1); + rptr = (unsigned char *) (result+size-1); + carry = 0; + + while (size-- > 0) + { + value = *nptr-- * digit + carry; + *rptr-- = value % BASE; + carry = value / BASE; + } + + if (carry != 0) *rptr = carry; + } + } +} + + +/* The full division routine. This computes N1 / N2. It returns + 0 if the division is ok and the result is in QUOT. The number of + digits after the decimal point is SCALE. It returns -1 if division + by zero is tried. The algorithm is found in Knuth Vol 2. p237. */ + +int +bc_divide (bc_num n1, bc_num n2, bc_num *quot, int scale TSRMLS_DC) +{ + bc_num qval; + unsigned char *num1, *num2; + unsigned char *ptr1, *ptr2, *n2ptr, *qptr; + int scale1, val; + unsigned int len1, len2, scale2, qdigits, extra, count; + unsigned int qdig, qguess, borrow, carry; + unsigned char *mval; + char zero; + unsigned int norm; + + /* Test for divide by zero. */ + if (bc_is_zero (n2 TSRMLS_CC)) return -1; + + /* Test for divide by 1. If it is we must truncate. */ + if (n2->n_scale == 0) + { + if (n2->n_len == 1 && *n2->n_value == 1) + { + qval = bc_new_num (n1->n_len, scale); + qval->n_sign = (n1->n_sign == n2->n_sign ? PLUS : MINUS); + memset (&qval->n_value[n1->n_len],0,scale); + memcpy (qval->n_value, n1->n_value, + n1->n_len + MIN(n1->n_scale,scale)); + bc_free_num (quot); + *quot = qval; + } + } + + /* Set up the divide. Move the decimal point on n1 by n2's scale. + Remember, zeros on the end of num2 are wasted effort for dividing. */ + scale2 = n2->n_scale; + n2ptr = (unsigned char *) n2->n_value+n2->n_len+scale2-1; + while ((scale2 > 0) && (*n2ptr-- == 0)) scale2--; + + len1 = n1->n_len + scale2; + scale1 = n1->n_scale - scale2; + if (scale1 < scale) + extra = scale - scale1; + else + extra = 0; + num1 = (unsigned char *) safe_emalloc (1, n1->n_len+n1->n_scale, extra+2); + if (num1 == NULL) bc_out_of_memory(); + memset (num1, 0, n1->n_len+n1->n_scale+extra+2); + memcpy (num1+1, n1->n_value, n1->n_len+n1->n_scale); + + len2 = n2->n_len + scale2; + num2 = (unsigned char *) safe_emalloc (1, len2, 1); + if (num2 == NULL) bc_out_of_memory(); + memcpy (num2, n2->n_value, len2); + *(num2+len2) = 0; + n2ptr = num2; + while (*n2ptr == 0) + { + n2ptr++; + len2--; + } + + /* Calculate the number of quotient digits. */ + if (len2 > len1+scale) + { + qdigits = scale+1; + zero = TRUE; + } + else + { + zero = FALSE; + if (len2>len1) + qdigits = scale+1; /* One for the zero integer part. */ + else + qdigits = len1-len2+scale+1; + } + + /* Allocate and zero the storage for the quotient. */ + qval = bc_new_num (qdigits-scale,scale); + memset (qval->n_value, 0, qdigits); + + /* Allocate storage for the temporary storage mval. */ + mval = (unsigned char *) safe_emalloc (1, len2, 1); + if (mval == NULL) bc_out_of_memory (); + + /* Now for the full divide algorithm. */ + if (!zero) + { + /* Normalize */ + norm = 10 / ((int)*n2ptr + 1); + if (norm != 1) + { + _one_mult (num1, len1+scale1+extra+1, norm, num1); + _one_mult (n2ptr, len2, norm, n2ptr); + } + + /* Initialize divide loop. */ + qdig = 0; + if (len2 > len1) + qptr = (unsigned char *) qval->n_value+len2-len1; + else + qptr = (unsigned char *) qval->n_value; + + /* Loop */ + while (qdig <= len1+scale-len2) + { + /* Calculate the quotient digit guess. */ + if (*n2ptr == num1[qdig]) + qguess = 9; + else + qguess = (num1[qdig]*10 + num1[qdig+1]) / *n2ptr; + + /* Test qguess. */ + if (n2ptr[1]*qguess > + (num1[qdig]*10 + num1[qdig+1] - *n2ptr*qguess)*10 + + num1[qdig+2]) + { + qguess--; + /* And again. */ + if (n2ptr[1]*qguess > + (num1[qdig]*10 + num1[qdig+1] - *n2ptr*qguess)*10 + + num1[qdig+2]) + qguess--; + } + + /* Multiply and subtract. */ + borrow = 0; + if (qguess != 0) + { + *mval = 0; + _one_mult (n2ptr, len2, qguess, mval+1); + ptr1 = (unsigned char *) num1+qdig+len2; + ptr2 = (unsigned char *) mval+len2; + for (count = 0; count < len2+1; count++) + { + val = (int) *ptr1 - (int) *ptr2-- - borrow; + if (val < 0) + { + val += 10; + borrow = 1; + } + else + borrow = 0; + *ptr1-- = val; + } + } + + /* Test for negative result. */ + if (borrow == 1) + { + qguess--; + ptr1 = (unsigned char *) num1+qdig+len2; + ptr2 = (unsigned char *) n2ptr+len2-1; + carry = 0; + for (count = 0; count < len2; count++) + { + val = (int) *ptr1 + (int) *ptr2-- + carry; + if (val > 9) + { + val -= 10; + carry = 1; + } + else + carry = 0; + *ptr1-- = val; + } + if (carry == 1) *ptr1 = (*ptr1 + 1) % 10; + } + + /* We now know the quotient digit. */ + *qptr++ = qguess; + qdig++; + } + } + + /* Clean up and return the number. */ + qval->n_sign = ( n1->n_sign == n2->n_sign ? PLUS : MINUS ); + if (bc_is_zero (qval TSRMLS_CC)) qval->n_sign = PLUS; + _bc_rm_leading_zeros (qval); + bc_free_num (quot); + *quot = qval; + + /* Clean up temporary storage. */ + efree (mval); + efree (num1); + efree (num2); + + return 0; /* Everything is OK. */ +} + |