Diff: math/bin/fp_read_radix.c

Revision:

4:cbaf466d717d

Parent:

0:35aa5be3b78d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/math/bin/fp_read_radix.c	Tue Jun 10 14:23:09 2014 +0000
@@ -0,0 +1,70 @@
+/* TomsFastMath, a fast ISO C bignum library.
+ * 
+ * This project is meant to fill in where LibTomMath
+ * falls short.  That is speed ;-)
+ *
+ * This project is public domain and free for all purposes.
+ * 
+ * Tom St Denis, tomstdenis@gmail.com
+ */
+#include <tfm.h>
+
+int fp_read_radix(fp_int *a, char *str, int radix)
+{
+  int     y, neg;
+  char    ch;
+
+  /* make sure the radix is ok */
+  if (radix < 2 || radix > 64) {
+    return FP_VAL;
+  }
+
+  /* if the leading digit is a
+   * minus set the sign to negative.
+   */
+  if (*str == '-') {
+    ++str;
+    neg = FP_NEG;
+  } else {
+    neg = FP_ZPOS;
+  }
+
+  /* set the integer to the default of zero */
+  fp_zero (a);
+
+  /* process each digit of the string */
+  while (*str) {
+    /* if the radix < 36 the conversion is case insensitive
+     * this allows numbers like 1AB and 1ab to represent the same  value
+     * [e.g. in hex]
+     */
+    ch = (char) ((radix < 36) ? toupper (*str) : *str);
+    for (y = 0; y < 64; y++) {
+      if (ch == fp_s_rmap[y]) {
+         break;
+      }
+    }
+
+    /* if the char was found in the map
+     * and is less than the given radix add it
+     * to the number, otherwise exit the loop.
+     */
+    if (y < radix) {
+      fp_mul_d (a, (fp_digit) radix, a);
+      fp_add_d (a, (fp_digit) y, a);
+    } else {
+      break;
+    }
+    ++str;
+  }
+
+  /* set the sign only if a != 0 */
+  if (fp_iszero(a) != FP_YES) {
+     a->sign = neg;
+  }
+  return FP_OKAY;
+}
+
+/* $Source: /cvs/libtom/tomsfastmath/src/bin/fp_read_radix.c,v $ */
+/* $Revision: 1.1 $ */
+/* $Date: 2006/12/31 21:25:53 $ */