summaryrefslogtreecommitdiff
path: root/ext/bcmath/libbcmath/src/div.c
diff options
context:
space:
mode:
authorLorry Tar Creator <lorry-tar-importer@baserock.org>2013-03-14 05:42:27 +0000
committer <>2013-04-03 16:25:08 +0000
commitc4dd7a1a684490673e25aaf4fabec5df138854c4 (patch)
tree4d57c44caae4480efff02b90b9be86f44bf25409 /ext/bcmath/libbcmath/src/div.c
downloadphp2-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.c274
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. */
+}
+