42 lines
1.1 KiB
C
42 lines
1.1 KiB
C
#include <tommath_private.h>
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#ifdef BN_MP_GET_LONG_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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/* get the lower unsigned long of an mp_int, platform dependent */
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unsigned long mp_get_long(const mp_int *a)
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{
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int i;
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unsigned long res;
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if (a->used == 0) {
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return 0;
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}
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/* get number of digits of the lsb we have to read */
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i = MIN(a->used, (int)(((sizeof(unsigned long) * CHAR_BIT) + DIGIT_BIT - 1) / DIGIT_BIT)) - 1;
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/* get most significant digit of result */
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res = DIGIT(a, i);
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#if (ULONG_MAX != 0xffffffffuL) || (DIGIT_BIT < 32)
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while (--i >= 0) {
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res = (res << DIGIT_BIT) | DIGIT(a, i);
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}
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#endif
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return res;
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}
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#endif
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