Mercurial > dropbear
view libtommath/bn_mp_radix_size.c @ 1663:c795520269f9
Fallback for key gen without hard link support (#89)
Add a non-atomic fallback for key generation on platforms where link()
is not permitted (such as most stock Android installs) or on filesystems
without hard link support (such as FAT).
author | Matt Robinson <git@nerdoftheherd.com> |
---|---|
date | Sat, 14 Mar 2020 14:37:35 +0000 |
parents | f52919ffd3b1 |
children | 1051e4eea25a |
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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. * * SPDX-License-Identifier: Unlicense */ /* returns size of ASCII reprensentation */ int mp_radix_size(const 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: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */