59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
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/* TomsFastMath, a fast ISO C bignum library.
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* That project is public domain and free for all purposes.
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* fp_toradix_n included in TomsFastMath specification (tfm.h), but unimplemented until now.
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* It is based on conversion of mp_toradix_n from libtommath
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* Will send the body of this function back to the LibTom projects, if they want it
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*/
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#include "bignum_fast.h"
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int fp_toradix_n(fp_int *a, char *str, int radix, int maxlen)
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{
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int digs;
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fp_int t;
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fp_digit d;
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char *_s = str;
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/* check range of the maxlen, radix */
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if (maxlen < 2 || radix < 2 || radix > 64) {
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return FP_VAL;
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}
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/* quick out if its zero */
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if (fp_iszero(a) == 1) {
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*str++ = '0';
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*str = '\0';
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return FP_OKAY;
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}
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fp_init_copy(&t, a);
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/* if it is negative output a - */
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if (t.sign == FP_NEG) {
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++_s;
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*str++ = '-';
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t.sign = FP_ZPOS;
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--maxlen;
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}
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digs = 0;
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while (fp_iszero (&t) == FP_NO) {
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if (--maxlen < 1) {
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/* no more room */
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break;
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}
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fp_div_d (&t, (fp_digit) radix, &t, &d);
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*str++ = fp_s_rmap[d];
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++digs;
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}
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/* reverse the digits of the string. In this case _s points
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* to the first digit [exluding the sign] of the number]
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*/
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fp_reverse ((unsigned char *)_s, digs);
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/* append a NULL so the string is properly terminated */
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*str = '\0';
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return FP_OKAY;
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}
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