89 lines
2.0 KiB
C
89 lines
2.0 KiB
C
#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.
|
|
*
|
|
* The library is free for all purposes without any express
|
|
* guarantee it works.
|
|
*
|
|
* Tom St Denis, tstdenis82@gmail.com, http://libtom.org
|
|
*/
|
|
|
|
/* 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, 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] == 4) ? -1 : 1;
|
|
}
|
|
|
|
odd_nails = (nails % 8);
|
|
odd_nail_mask = 0xff;
|
|
for (i = 0; i < odd_nails; ++i) {
|
|
odd_nail_mask ^= (1 << (7 - i));
|
|
}
|
|
nail_bytes = nails / 8;
|
|
|
|
bits = mp_count_bits(&t);
|
|
count = (bits / ((size * 8) - nails)) + (((bits % ((size * 8) - nails)) != 0) ? 1 : 0);
|
|
|
|
for (i = 0; i < count; ++i) {
|
|
for (j = 0; j < size; ++j) {
|
|
unsigned char* byte = (
|
|
(unsigned char*)rop +
|
|
(((order == -1) ? i : ((count - 1) - i)) * size) +
|
|
((endian == -1) ? j : ((size - 1) - j))
|
|
);
|
|
|
|
if (j >= (size - nail_bytes)) {
|
|
*byte = 0;
|
|
continue;
|
|
}
|
|
|
|
*byte = (unsigned char)((j == ((size - nail_bytes) - 1)) ? (t.dp[0] & odd_nail_mask) : (t.dp[0] & 0xFF));
|
|
|
|
if ((result = mp_div_2d(&t, ((j == ((size - nail_bytes) - 1)) ? (8 - odd_nails) : 8), &t, NULL)) != MP_OKAY) {
|
|
mp_clear(&t);
|
|
return result;
|
|
}
|
|
}
|
|
}
|
|
|
|
mp_clear(&t);
|
|
|
|
if (countp != NULL) {
|
|
*countp = count;
|
|
}
|
|
|
|
return MP_OKAY;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* $Source$ */
|
|
/* $Revision$ */
|
|
/* $Date$ */
|