Mercurial > dropbear
diff libtommath/bn_mp_import.c @ 1436:60fc6476e044
Update to libtommath v1.0
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sat, 24 Jun 2017 22:37:14 +0800 |
parents | |
children | 8bba51a55704 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_import.c Sat Jun 24 22:37:14 2017 +0800 @@ -0,0 +1,73 @@ +#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 + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */