tommath/bn_mp_cmp_mag.c

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/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
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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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* The library was designed directly after the MPI library by
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* 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.
*
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* Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
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*/
#include <tommath.h>
/* compare maginitude of two ints (unsigned) */
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int mp_cmp_mag (mp_int * a, mp_int * b)
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{
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int n;
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mp_digit *tmpa, *tmpb;
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/* compare based on # of non-zero digits */
if (a->used > b->used) {
return MP_GT;
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}
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if (a->used < b->used) {
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return MP_LT;
}
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/* alias for a */
tmpa = a->dp + (a->used - 1);
/* alias for b */
tmpb = b->dp + (a->used - 1);
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/* compare based on digits */
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for (n = 0; n < a->used; ++n, --tmpa, --tmpb) {
if (*tmpa > *tmpb) {
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return MP_GT;
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}
if (*tmpa < *tmpb) {
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return MP_LT;
}
}
return MP_EQ;
}