diff options
author | Matt Johnston <matt@ucc.asn.au> | 2006-03-21 16:20:59 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2006-03-21 16:20:59 +0000 |
commit | f7caf6f5c640cb1756c01184898f176438a3a0c2 (patch) | |
tree | 4d32de11b18d5f6296207961b5f25d0949af80c0 /libtommath/bn_mp_toradix_n.c | |
parent | e444f0cfe67c71d3f38854f27cefae9aea6c4cd9 (diff) | |
parent | 3f49fc5f2ca0ec4adb5cac081f502cbb86702efa (diff) |
propagate from branch 'au.asn.ucc.matt.dropbear' (head 0501e6f661b5415eb76f3b312d183c3adfbfb712)
to branch 'au.asn.ucc.matt.dropbear.cli-agent' (head 01038174ec27245b51bd43a66c01ad930880f67b)
--HG--
branch : agent-client
extra : convert_revision : 12b2f59db65e7339d340e95ac67d6d9ddb193c2b
Diffstat (limited to 'libtommath/bn_mp_toradix_n.c')
-rw-r--r-- | libtommath/bn_mp_toradix_n.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/libtommath/bn_mp_toradix_n.c b/libtommath/bn_mp_toradix_n.c new file mode 100644 index 0000000..7d43558 --- /dev/null +++ b/libtommath/bn_mp_toradix_n.c @@ -0,0 +1,85 @@ +#include <tommath.h> +#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@iahu.ca, http://math.libtomcrypt.org + */ + +/* 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 < 3 || radix < 2 || radix > 64) { + return MP_VAL; + } + + /* quick out if its zero */ + if (mp_iszero(a) == 1) { + *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 ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) { + mp_clear (&t); + return res; + } + *str++ = mp_s_rmap[d]; + ++digs; + + if (--maxlen == 1) { + /* no more room */ + break; + } + } + + /* 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 |