#include #ifdef BN_MP_TORADIX_N_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 */ /* stores a bignum as a ASCII string in a given radix (2..64) * * Stores upto maxlen-1 chars and always a NULL byte */ int mp_toradix_n(mp_int * a, char *str, int radix, int maxlen) { int res, digs; mp_int t; mp_digit d; char *_s = str; /* check range of the maxlen, radix */ if (maxlen < 2 || radix < 2 || radix > 64) { return MP_VAL; } /* quick out if its zero */ if (mp_iszero(a) == MP_YES) { *str++ = '0'; *str = '\0'; return MP_OKAY; } if ((res = mp_init_copy (&t, a)) != MP_OKAY) { return res; } /* if it is negative output a - */ if (t.sign == MP_NEG) { /* we have to reverse our digits later... but not the - sign!! */ ++_s; /* store the flag and mark the number as positive */ *str++ = '-'; t.sign = MP_ZPOS; /* subtract a char */ --maxlen; } digs = 0; while (mp_iszero (&t) == 0) { if (--maxlen < 1) { /* no more room */ break; } if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) { mp_clear (&t); return res; } *str++ = mp_s_rmap[d]; ++digs; } /* reverse the digits of the string. In this case _s points * to the first digit [exluding the sign] of the number */ bn_reverse ((unsigned char *)_s, digs); /* append a NULL so the string is properly terminated */ *str = '\0'; mp_clear (&t); return MP_OKAY; } #endif /* $Source: /cvsroot/tcl/libtommath/bn_mp_toradix_n.c,v $ */ /* $Revision: 1.1.1.4 $ */ /* $Date: 2006/12/01 00:08:11 $ */