74 lines
1.7 KiB
C
74 lines
1.7 KiB
C
#include <tommath_private.h>
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#ifdef BN_MP_IMPORT_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library was designed directly after the MPI library by
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* Michael Fromberger but has been written from scratch with
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* additional optimizations in place.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tstdenis82@gmail.com, http://libtom.org
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*/
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/* based on gmp's mpz_import.
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* see http://gmplib.org/manual/Integer-Import-and-Export.html
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*/
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int mp_import(mp_int* rop, size_t count, int order, size_t size,
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int endian, size_t nails, const void* op) {
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int result;
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size_t odd_nails, nail_bytes, i, j;
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unsigned char odd_nail_mask;
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mp_zero(rop);
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if (endian == 0) {
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union {
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unsigned int i;
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char c[4];
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} lint;
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lint.i = 0x01020304;
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endian = (lint.c[0] == 4 ? -1 : 1);
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}
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odd_nails = (nails % 8);
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odd_nail_mask = 0xff;
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for (i = 0; i < odd_nails; ++i) {
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odd_nail_mask ^= (1 << (7 - i));
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}
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nail_bytes = nails / 8;
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for (i = 0; i < count; ++i) {
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for (j = 0; j < size - nail_bytes; ++j) {
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unsigned char byte = *(
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(unsigned char*)op +
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(order == 1 ? i : count - 1 - i) * size +
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(endian == 1 ? j + nail_bytes : size - 1 - j - nail_bytes)
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);
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if (
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(result = mp_mul_2d(rop, (j == 0 ? 8 - odd_nails : 8), rop)) != MP_OKAY) {
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return result;
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}
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rop->dp[0] |= (j == 0 ? (byte & odd_nail_mask) : byte);
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rop->used += 1;
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}
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}
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mp_clamp(rop);
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return MP_OKAY;
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}
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#endif
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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