Mercurial > dropbear
diff tomsfastmath/src/bin/fp_read_radix.c @ 643:a362b62d38b2 dropbear-tfm
Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a
with Makefile.in renamed
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 23 Nov 2011 18:10:20 +0700 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tomsfastmath/src/bin/fp_read_radix.c Wed Nov 23 18:10:20 2011 +0700 @@ -0,0 +1,70 @@ +/* TomsFastMath, a fast ISO C bignum library. + * + * This project is meant to fill in where LibTomMath + * falls short. That is speed ;-) + * + * This project is public domain and free for all purposes. + * + * Tom St Denis, [email protected] + */ +#include <tfm.h> + +int fp_read_radix(fp_int *a, char *str, int radix) +{ + int y, neg; + char ch; + + /* make sure the radix is ok */ + if (radix < 2 || radix > 64) { + return FP_VAL; + } + + /* if the leading digit is a + * minus set the sign to negative. + */ + if (*str == '-') { + ++str; + neg = FP_NEG; + } else { + neg = FP_ZPOS; + } + + /* set the integer to the default of zero */ + fp_zero (a); + + /* process each digit of the string */ + while (*str) { + /* if the radix < 36 the conversion is case insensitive + * this allows numbers like 1AB and 1ab to represent the same value + * [e.g. in hex] + */ + ch = (char) ((radix < 36) ? toupper ((int)*str) : *str); + for (y = 0; y < 64; y++) { + if (ch == fp_s_rmap[y]) { + break; + } + } + + /* if the char was found in the map + * and is less than the given radix add it + * to the number, otherwise exit the loop. + */ + if (y < radix) { + fp_mul_d (a, (fp_digit) radix, a); + fp_add_d (a, (fp_digit) y, a); + } else { + break; + } + ++str; + } + + /* set the sign only if a != 0 */ + if (fp_iszero(a) != FP_YES) { + a->sign = neg; + } + return FP_OKAY; +} + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */