Mercurial > dropbear
view libtommath/bn_mp_radix_size.c @ 1471:6dba84798cd5
Update to libtomcrypt 1.18.1, merged with Dropbear changes
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Fri, 09 Feb 2018 21:44:05 +0800 |
parents | 8bba51a55704 |
children | f52919ffd3b1 |
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#include <tommath_private.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, [email protected], http://libtom.org */ /* 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; /* 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; } /* special case for binary */ if (radix == 2) { *size = mp_count_bits (a) + ((a->sign == MP_NEG) ? 1 : 0) + 1; 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 /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */