Mercurial > dropbear
view libtommath/bn_mp_get_bit.c @ 1684:d5d25ce2a2ed
cast to fix warning
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 26 May 2020 19:57:28 +0800 |
parents | f52919ffd3b1 |
children |
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#include "tommath_private.h" #ifdef BN_MP_GET_BIT_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 */ /* Checks the bit at position b and returns MP_YES if the bit is 1, MP_NO if it is 0 and MP_VAL in case of error */ int mp_get_bit(const mp_int *a, int b) { int limb; mp_digit bit, isset; if (b < 0) { return MP_VAL; } limb = b / DIGIT_BIT; /* * Zero is a special value with the member "used" set to zero. * Needs to be tested before the check for the upper boundary * otherwise (limb >= a->used) would be true for a = 0 */ if (mp_iszero(a) != MP_NO) { return MP_NO; } if (limb >= a->used) { return MP_VAL; } bit = (mp_digit)(1) << (b % DIGIT_BIT); isset = a->dp[limb] & bit; return (isset != 0u) ? MP_YES : MP_NO; } #endif /* ref: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */