|
1
|
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
|
|
2 * |
|
|
3 * LibTomMath is a library that provides multiple-precision |
|
|
4 * integer arithmetic as well as number theoretic functionality. |
|
|
5 * |
|
|
6 * The library was designed directly after the MPI library by |
|
|
7 * Michael Fromberger but has been written from scratch with |
|
|
8 * additional optimizations in place. |
|
|
9 * |
|
|
10 * The library is free for all purposes without any express |
|
|
11 * guarantee it works. |
|
|
12 * |
|
|
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org |
|
|
14 */ |
|
|
15 #include <tommath.h> |
|
|
16 |
|
|
17 /* read signed bin, big endian, first byte is 0==positive or 1==negative */ |
|
|
18 int |
|
|
19 mp_read_signed_bin (mp_int * a, unsigned char *b, int c) |
|
|
20 { |
|
|
21 int res; |
|
|
22 |
|
|
23 /* read magnitude */ |
|
|
24 if ((res = mp_read_unsigned_bin (a, b + 1, c - 1)) != MP_OKAY) { |
|
|
25 return res; |
|
|
26 } |
|
|
27 |
|
|
28 /* first byte is 0 for positive, non-zero for negative */ |
|
|
29 if (b[0] == 0) { |
|
|
30 a->sign = MP_ZPOS; |
|
|
31 } else { |
|
|
32 a->sign = MP_NEG; |
|
|
33 } |
|
|
34 |
|
|
35 return MP_OKAY; |
|
|
36 } |
