#include <tommath.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, tomstdenis@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 = {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) ? 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) {
*countp = count;
}
return MP_OKAY;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
