Mercurial > dropbear
annotate libtommath/bn_mp_import.c @ 1525:10994a613a6b
12 years is too old for a TODO list
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Tue, 20 Feb 2018 19:30:34 +0800 |
| parents | 8bba51a55704 |
| children | f52919ffd3b1 |
| rev | line source |
|---|---|
| 1436 | 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 | |
|
1470
8bba51a55704
Update to libtommath v1.0.1
Matt Johnston <matt@ucc.asn.au>
parents:
1436
diff
changeset
|
71 /* ref: $Format:%D$ */ |
|
8bba51a55704
Update to libtommath v1.0.1
Matt Johnston <matt@ucc.asn.au>
parents:
1436
diff
changeset
|
72 /* git commit: $Format:%H$ */ |
|
8bba51a55704
Update to libtommath v1.0.1
Matt Johnston <matt@ucc.asn.au>
parents:
1436
diff
changeset
|
73 /* commit time: $Format:%ai$ */ |