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comparison libtommath/bn_mp_read_unsigned_bin.c @ 284:eed26cff980b

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583) to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:49 +0000
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children 5ff8218bcee9
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283:bd240aa12ba7 284:eed26cff980b
1 #include <tommath.h>
2 #ifdef BN_MP_READ_UNSIGNED_BIN_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://math.libtomcrypt.org
16 */
17
18 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
19 int
20 mp_read_unsigned_bin (mp_int * a, unsigned char *b, int c)
21 {
22 int res;
23
24 /* make sure there are at least two digits */
25 if (a->alloc < 2) {
26 if ((res = mp_grow(a, 2)) != MP_OKAY) {
27 return res;
28 }
29 }
30
31 /* zero the int */
32 mp_zero (a);
33
34 /* read the bytes in */
35 while (c-- > 0) {
36 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
37 return res;
38 }
39
40 #ifndef MP_8BIT
41 a->dp[0] |= *b++;
42 a->used += 1;
43 #else
44 a->dp[0] = (*b & MP_MASK);
45 a->dp[1] |= ((*b++ >> 7U) & 1);
46 a->used += 2;
47 #endif
48 }
49 mp_clamp (a);
50 return MP_OKAY;
51 }
52 #endif