Mercurial > dropbear
diff libtommath/bn_mp_unpack.c @ 1733:d529a52b2f7c coverity coverity
merge coverity from main
author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 26 Jun 2020 21:07:34 +0800 |
parents | 1051e4eea25a |
children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_unpack.c Fri Jun 26 21:07:34 2020 +0800 @@ -0,0 +1,49 @@ +#include "tommath_private.h" +#ifdef BN_MP_UNPACK_C +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ + +/* based on gmp's mpz_import. + * see http://gmplib.org/manual/Integer-Import-and-Export.html + */ +mp_err mp_unpack(mp_int *rop, size_t count, mp_order order, size_t size, + mp_endian endian, size_t nails, const void *op) +{ + mp_err err; + size_t odd_nails, nail_bytes, i, j; + unsigned char odd_nail_mask; + + mp_zero(rop); + + if (endian == MP_NATIVE_ENDIAN) { + MP_GET_ENDIANNESS(endian); + } + + odd_nails = (nails % 8u); + odd_nail_mask = 0xff; + for (i = 0; i < odd_nails; ++i) { + odd_nail_mask ^= (unsigned char)(1u << (7u - i)); + } + nail_bytes = nails / 8u; + + for (i = 0; i < count; ++i) { + for (j = 0; j < (size - nail_bytes); ++j) { + unsigned char byte = *((const unsigned char *)op + + (((order == MP_MSB_FIRST) ? i : ((count - 1u) - i)) * size) + + ((endian == MP_BIG_ENDIAN) ? (j + nail_bytes) : (((size - 1u) - j) - nail_bytes))); + + if ((err = mp_mul_2d(rop, (j == 0u) ? (int)(8u - odd_nails) : 8, rop)) != MP_OKAY) { + return err; + } + + rop->dp[0] |= (j == 0u) ? (mp_digit)(byte & odd_nail_mask) : (mp_digit)byte; + rop->used += 1; + } + } + + mp_clamp(rop); + + return MP_OKAY; +} + +#endif