exponentiation.tcc

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/** @file
 *****************************************************************************
 
 Implementation of interfaces for (square-and-multiply) exponentiation.
 
 See exponentiation.hpp .
 
 *****************************************************************************
 * @author     This file is part of libff, developed by SCIPR Lab
 *             and contributors (see AUTHORS).
 * @copyright  MIT license (see LICENSE file)
 *****************************************************************************/
 
#ifndef EXPONENTIATION_TCC_
#define EXPONENTIATION_TCC_
 
#include <libff/common/utils.hpp>
 
namespace libff
{
 
template<typename FieldT, mp_size_t m>
FieldT power(const FieldT &base, const bigint<m> &exponent)
{
    FieldT result = FieldT::one();
 
    bool found_one = false;
 
    for (long i = exponent.max_bits() - 1; i >= 0; --i) {
        if (found_one) {
            result = result * result;
        }
 
        if (exponent.test_bit(i)) {
            found_one = true;
            result = result * base;
        }
    }
 
    return result;
}
 
template<typename FieldT>
FieldT power(const FieldT &base, const unsigned long exponent)
{
    return power<FieldT>(base, bigint<1>(exponent));
}
 
} // namespace libff
 
#endif // EXPONENTIATION_TCC_