/*

* Fused and Important MP Algorithms

* (C) 1999-2007 Jack Lloyd

*     2016 Matthias Gierlings

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/numthry.h>

#include <botan/internal/mp_core.h>

#include <botan/internal/rounding.h>

#include <algorithm>

namespace Botan {

/*

* Square a BigInt

*/

BigInt square(const BigInt& x)

   {

   BigInt z = x;

   secure_vector<word> ws;

   z.square(ws);

   return z;

   }

/*

* Multiply-Add Operation

*/

BigInt mul_add(const BigInt& a, const BigInt& b, const BigInt& c)

   {

   if(c.is_negative())

      throw Invalid_Argument("mul_add: Third argument must be > 0");

   BigInt::Sign sign = BigInt::Positive;

   if(a.sign() != b.sign())

      sign = BigInt::Negative;

   const size_t a_sw = a.sig_words();

   const size_t b_sw = b.sig_words();

   const size_t c_sw = c.sig_words();

   BigInt r(sign, std::max(a_sw + b_sw, c_sw) + 1);

   secure_vector<word> workspace(r.size());

   bigint_mul(r.mutable_data(), r.size(),

              a.data(), a.size(), a_sw,

              b.data(), b.size(), b_sw,

              workspace.data(), workspace.size());

   const size_t r_size = std::max(r.sig_words(), c_sw);

   bigint_add2(r.mutable_data(), r_size, c.data(), c_sw);

   return r;

   }

/*

* Subtract-Multiply Operation

*/

BigInt sub_mul(const BigInt& a, const BigInt& b, const BigInt& c)

   {

   if(a.is_negative() || b.is_negative())

      throw Invalid_Argument("sub_mul: First two arguments must be >= 0");

   BigInt r = a;

   r -= b;

   r *= c;

   return r;

   }

/*

* Multiply-Subtract Operation

*/

BigInt mul_sub(const BigInt& a, const BigInt& b, const BigInt& c)

   {

   if(c.is_negative() || c.is_zero())

      throw Invalid_Argument("mul_sub: Third argument must be > 0");

   BigInt r = a;

   r *= b;

   r -= c;

   return r;

   }

}