X-Git-Url: https://mattmccutchen.net/bigint/bigint.git/blobdiff_plain/3e1327901d299a537a8d932c49dd330f87ac3bda..0afe80d551aa9b66b574b956cf681692399fc728:/BigIntegerAlgorithms.hh diff --git a/BigIntegerAlgorithms.hh b/BigIntegerAlgorithms.hh new file mode 100644 index 0000000..b1dd943 --- /dev/null +++ b/BigIntegerAlgorithms.hh @@ -0,0 +1,25 @@ +#ifndef BIGINTEGERALGORITHMS_H +#define BIGINTEGERALGORITHMS_H + +#include "BigInteger.hh" + +/* Some mathematical algorithms for big integers. + * This code is new and, as such, experimental. */ + +// Returns the greatest common divisor of a and b. +BigUnsigned gcd(BigUnsigned a, BigUnsigned b); + +/* Extended Euclidean algorithm. + * Given m and n, finds gcd g and numbers r, s such that r*m + s*n == g. */ +void extendedEuclidean(BigInteger m, BigInteger n, + BigInteger &g, BigInteger &r, BigInteger &s); + +/* Returns the multiplicative inverse of x modulo n, or throws an exception if + * they have a common factor. */ +BigUnsigned modinv(const BigInteger &x, const BigUnsigned &n); + +// Returns (base ^ exponent) % modulus. +BigUnsigned modexp(const BigInteger &base, const BigUnsigned &exponent, + const BigUnsigned &modulus); + +#endif