Mercurial > dropbear
view libtommath/bn_mp_export.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_EXPORT_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 */ /* based on gmp's mpz_export. * see http://gmplib.org/manual/Integer-Import-and-Export.html */ int mp_export(void *rop, size_t *countp, int order, size_t size, int endian, size_t nails, const mp_int *op) { int result; size_t odd_nails, nail_bytes, i, j, bits, count; unsigned char odd_nail_mask; mp_int t; if ((result = mp_init_copy(&t, op)) != MP_OKAY) { return result; } if (endian == 0) { union { unsigned int i; char c[4]; } lint; lint.i = 0x01020304; endian = (lint.c[0] == '\x04') ? -1 : 1; } 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; bits = (size_t)mp_count_bits(&t); count = (bits / ((size * 8u) - nails)) + (((bits % ((size * 8u) - nails)) != 0u) ? 1u : 0u); for (i = 0; i < count; ++i) { for (j = 0; j < size; ++j) { unsigned char *byte = (unsigned char *)rop + (((order == -1) ? i : ((count - 1u) - i)) * size) + ((endian == -1) ? j : ((size - 1u) - j)); if (j >= (size - nail_bytes)) { *byte = 0; continue; } *byte = (unsigned char)((j == ((size - nail_bytes) - 1u)) ? (t.dp[0] & odd_nail_mask) : (t.dp[0] & 0xFFuL)); if ((result = mp_div_2d(&t, (j == ((size - nail_bytes) - 1u)) ? (int)(8u - odd_nails) : 8, &t, NULL)) != MP_OKAY) { mp_clear(&t); return result; } } } mp_clear(&t); if (countp != NULL) { *countp = count; } return MP_OKAY; } #endif /* ref: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */