40 lines
1.0 KiB
C
40 lines
1.0 KiB
C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is library that provides for multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library is 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, tomstdenis@iahu.ca, http://math.libtomcrypt.org
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*/
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#include <tommath.h>
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/* reads a unsigned char array, assumes the msb is stored first [big endian] */
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int
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mp_read_unsigned_bin (mp_int * a, unsigned char *b, int c)
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{
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int res;
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mp_zero (a);
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while (c-- > 0) {
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if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
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return res;
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}
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if (DIGIT_BIT != 7) {
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a->dp[0] |= *b++;
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a->used += 1;
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} else {
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a->dp[0] = (*b & MP_MASK);
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a->dp[1] |= ((*b++ >> 7U) & 1);
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a->used += 2;
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}
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}
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mp_clamp (a);
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return MP_OKAY;
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}
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