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comparison libtommath/bn_mp_import.c @ 1436:60fc6476e044

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Update to libtommath v1.0
author Matt Johnston <matt@ucc.asn.au>
date Sat, 24 Jun 2017 22:37:14 +0800
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children 8bba51a55704
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1435:f849a5ca2efc 1436:60fc6476e044
1 #include <tommath_private.h>
2 #ifdef BN_MP_IMPORT_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
4 *
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, [email protected], http://libtom.org
16 */
17
18 /* based on gmp's mpz_import.
19 * see http://gmplib.org/manual/Integer-Import-and-Export.html
20 */
21 int mp_import(mp_int* rop, size_t count, int order, size_t size,
22 int endian, size_t nails, const void* op) {
23 int result;
24 size_t odd_nails, nail_bytes, i, j;
25 unsigned char odd_nail_mask;
26
27 mp_zero(rop);
28
29 if (endian == 0) {
30 union {
31 unsigned int i;
32 char c[4];
33 } lint;
34 lint.i = 0x01020304;
35
36 endian = (lint.c[0] == 4) ? -1 : 1;
37 }
38
39 odd_nails = (nails % 8);
40 odd_nail_mask = 0xff;
41 for (i = 0; i < odd_nails; ++i) {
42 odd_nail_mask ^= (1 << (7 - i));
43 }
44 nail_bytes = nails / 8;
45
46 for (i = 0; i < count; ++i) {
47 for (j = 0; j < (size - nail_bytes); ++j) {
48 unsigned char byte = *(
49 (unsigned char*)op +
50 (((order == 1) ? i : ((count - 1) - i)) * size) +
51 ((endian == 1) ? (j + nail_bytes) : (((size - 1) - j) - nail_bytes))
52 );
53
54 if (
55 (result = mp_mul_2d(rop, ((j == 0) ? (8 - odd_nails) : 8), rop)) != MP_OKAY) {
56 return result;
57 }
58
59 rop->dp[0] |= (j == 0) ? (byte & odd_nail_mask) : byte;
60 rop->used += 1;
61 }
62 }
63
64 mp_clamp(rop);
65
66 return MP_OKAY;
67 }
68
69 #endif
70
71 /* $Source$ */
72 /* $Revision$ */
73 /* $Date$ */