At long last, import the bcmath library, by Phil Nelson

1 files changed, 99 insertions, 0 deletions

diff --git a/ext/bcmath/libbcmath/src/raisemod.c b/ext/bcmath/libbcmath/src/raisemod.c
new file mode 100644
index 0000000000..cc9dd35a57
--- /dev/null
+++ b/ext/bcmath/libbcmath/src/raisemod.c
@@ -0,0 +1,99 @@
+/* raisemod.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 BASE to the EXPO power, reduced modulo MOD.  The result is
+   placed in RESULT.  If a EXPO is not an integer,
+   only the integer part is used.  */
+
+int
+bc_raisemod (base, expo, mod, result, scale)
+     bc_num base, expo, mod, *result;
+     int scale;
+{
+  bc_num power, exponent, parity, temp;
+  int rscale;
+
+  /* Check for correct numbers. */
+  if (bc_is_zero(mod)) return -1;
+  if (bc_is_neg(expo)) return -1;
+
+  /* Set initial values.  */
+  power = bc_copy_num (base);
+  exponent = bc_copy_num (expo);
+  temp = bc_copy_num (_one_);
+  bc_init_num(&parity);
+
+  /* Check the base for scale digits. */
+  if (base->n_scale != 0)
+      bc_rt_warn ("non-zero scale in base");
+
+  /* Check the exponent for scale digits. */
+  if (exponent->n_scale != 0)
+    {
+      bc_rt_warn ("non-zero scale in exponent");
+      bc_divide (exponent, _one_, &exponent, 0); /*truncate */
+    }
+
+  /* Check the modulus for scale digits. */
+  if (mod->n_scale != 0)
+      bc_rt_warn ("non-zero scale in modulus");
+
+  /* Do the calculation. */
+  rscale = MAX(scale, base->n_scale);
+  while ( !bc_is_zero(exponent) )
+    {
+      (void) bc_divmod (exponent, _two_, &exponent, &parity, 0);
+      if ( !bc_is_zero(parity) )
+	{
+	  bc_multiply (temp, power, &temp, rscale);
+	  (void) bc_modulo (temp, mod, &temp, scale);
+	}
+
+      bc_multiply (power, power, &power, rscale);
+      (void) bc_modulo (power, mod, &power, scale);
+    }
+
+  /* Assign the value. */
+  bc_free_num (&power);
+  bc_free_num (&exponent);
+  bc_free_num (result);
+  *result = temp;
+  return 0;	/* Everything is OK. */
+}