79 lines
1.8 KiB
C
79 lines
1.8 KiB
C
#include <tommath_private.h>
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#ifdef BN_MP_RADIX_SIZE_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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/* returns size of ASCII reprensentation */
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int mp_radix_size(const mp_int *a, int radix, int *size)
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{
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int res, digs;
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mp_int t;
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mp_digit d;
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*size = 0;
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/* make sure the radix is in range */
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if ((radix < 2) || (radix > 64)) {
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return MP_VAL;
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}
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if (mp_iszero(a) == MP_YES) {
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*size = 2;
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return MP_OKAY;
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}
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/* special case for binary */
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if (radix == 2) {
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*size = mp_count_bits(a) + ((a->sign == MP_NEG) ? 1 : 0) + 1;
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return MP_OKAY;
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}
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/* digs is the digit count */
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digs = 0;
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/* if it's negative add one for the sign */
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if (a->sign == MP_NEG) {
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++digs;
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}
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/* init a copy of the input */
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if ((res = mp_init_copy(&t, a)) != MP_OKAY) {
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return res;
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}
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/* force temp to positive */
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t.sign = MP_ZPOS;
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/* fetch out all of the digits */
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while (mp_iszero(&t) == MP_NO) {
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if ((res = mp_div_d(&t, (mp_digit)radix, &t, &d)) != MP_OKAY) {
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mp_clear(&t);
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return res;
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}
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++digs;
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}
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mp_clear(&t);
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/* return digs + 1, the 1 is for the NULL byte that would be required. */
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*size = digs + 1;
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return MP_OKAY;
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}
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#endif
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/* ref: $Format:%D$ */
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/* git commit: $Format:%H$ */
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/* commit time: $Format:%ai$ */
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