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authorMatt Johnston <matt@ucc.asn.au>2007-01-11 03:14:55 +0000
committerMatt Johnston <matt@ucc.asn.au>2007-01-11 03:14:55 +0000
commit9d5ed350a749368c84254c11e7616ce3c891193a (patch)
tree6dacbff2e9f5c60a1568382db55c72dd6d2ce925 /libtommath/bn_mp_radix_size.c
parentca52f070aecf91e75f6ae6c87d4ae1a2189ccb14 (diff)
parent5ea605d8de5b4438deb4fa86c5231710dd09f934 (diff)
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933) --HG-- extra : convert_revision : d26d5eb2837f46b56a33fb0e7573aa0201abd4d5
Diffstat (limited to 'libtommath/bn_mp_radix_size.c')
-rw-r--r--libtommath/bn_mp_radix_size.c78
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diff --git a/libtommath/bn_mp_radix_size.c b/libtommath/bn_mp_radix_size.c
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+++ b/libtommath/bn_mp_radix_size.c
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+#include <tommath.h>
+#ifdef BN_MP_RADIX_SIZE_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
+ */
+
+/* returns size of ASCII reprensentation */
+int mp_radix_size (mp_int * a, int radix, int *size)
+{
+ int res, digs;
+ mp_int t;
+ mp_digit d;
+
+ *size = 0;
+
+ /* special case for binary */
+ if (radix == 2) {
+ *size = mp_count_bits (a) + (a->sign == MP_NEG ? 1 : 0) + 1;
+ return MP_OKAY;
+ }
+
+ /* make sure the radix is in range */
+ if (radix < 2 || radix > 64) {
+ return MP_VAL;
+ }
+
+ if (mp_iszero(a) == MP_YES) {
+ *size = 2;
+ return MP_OKAY;
+ }
+
+ /* digs is the digit count */
+ digs = 0;
+
+ /* if it's negative add one for the sign */
+ if (a->sign == MP_NEG) {
+ ++digs;
+ }
+
+ /* init a copy of the input */
+ if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
+ return res;
+ }
+
+ /* force temp to positive */
+ t.sign = MP_ZPOS;
+
+ /* fetch out all of the digits */
+ while (mp_iszero (&t) == MP_NO) {
+ if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
+ mp_clear (&t);
+ return res;
+ }
+ ++digs;
+ }
+ mp_clear (&t);
+
+ /* return digs + 1, the 1 is for the NULL byte that would be required. */
+ *size = digs + 1;
+ return MP_OKAY;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_radix_size.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2006/03/31 14:18:44 $ */