Mercurial > dropbear
view libtommath/bn_mp_import.c @ 1473:67bcd5fa40c6
generate list of libtomcrypt directories automatically
author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 09 Feb 2018 23:33:41 +0800 |
parents | 8bba51a55704 |
children | f52919ffd3b1 |
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#include <tommath_private.h> #ifdef BN_MP_IMPORT_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, [email protected], http://libtom.org */ /* based on gmp's mpz_import. * see http://gmplib.org/manual/Integer-Import-and-Export.html */ int mp_import(mp_int* rop, size_t count, int order, size_t size, int endian, size_t nails, const void* op) { int result; size_t odd_nails, nail_bytes, i, j; unsigned char odd_nail_mask; mp_zero(rop); if (endian == 0) { union { unsigned int i; char c[4]; } lint; lint.i = 0x01020304; endian = (lint.c[0] == 4) ? -1 : 1; } odd_nails = (nails % 8); odd_nail_mask = 0xff; for (i = 0; i < odd_nails; ++i) { odd_nail_mask ^= (1 << (7 - i)); } nail_bytes = nails / 8; for (i = 0; i < count; ++i) { for (j = 0; j < (size - nail_bytes); ++j) { unsigned char byte = *( (unsigned char*)op + (((order == 1) ? i : ((count - 1) - i)) * size) + ((endian == 1) ? (j + nail_bytes) : (((size - 1) - j) - nail_bytes)) ); if ( (result = mp_mul_2d(rop, ((j == 0) ? (8 - odd_nails) : 8), rop)) != MP_OKAY) { return result; } rop->dp[0] |= (j == 0) ? (byte & odd_nail_mask) : byte; rop->used += 1; } } mp_clamp(rop); return MP_OKAY; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */