/*
   Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
   MA  02110-1301  USA.
*/

/* based on Wei Dai's integer.h from CryptoPP */


#ifndef TAO_CRYPT_INTEGER_HPP
#define TAO_CRYPT_INTEGER_HPP


#ifdef _MSC_VER
    // 4250: dominance
    // 4660: explicitly instantiating a class already implicitly instantiated
    // 4661: no suitable definition provided for explicit template request
    // 4786: identifer was truncated in debug information
    // 4355: 'this' : used in base member initializer list
#   pragma warning(disable: 4250 4660 4661 4786 4355)
#endif


#include "misc.hpp"
#include "block.hpp"
#include "random.hpp"
#include "file.hpp"
#include <string.h>
#ifdef USE_SYS_STL
    #include <algorithm>
#else
    #include "algorithm.hpp"
#endif


#ifdef TAOCRYPT_X86ASM_AVAILABLE
    #if defined(__GNUC__) && (__GNUC__ >= 4)
        // GCC 4 or greater optimizes too much inline on recursive for bigint, 
        // -O3 just as fast without asm here anyway
        #undef TAOCRYPT_X86ASM_AVAILABLE
    #endif
#endif

#ifdef TAOCRYPT_X86ASM_AVAILABLE

#ifdef _M_IX86
    #if (defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 500)) || \
      (defined(__ICL) && (__ICL >= 500))
        #define SSE2_INTRINSICS_AVAILABLE
        #define TAOCRYPT_MM_MALLOC_AVAILABLE
    #elif defined(_MSC_VER)
        // _mm_free seems to be the only way to tell if the Processor Pack is
        //installed or not
        #include <malloc.h>
        #if defined(_mm_free)
            #define SSE2_INTRINSICS_AVAILABLE
            #define TAOCRYPT_MM_MALLOC_AVAILABLE
        #endif
    #endif
#endif

// SSE2 intrinsics work in GCC 3.3 or later
#if defined(__SSE2__) && (__GNUC__ == 4 || __GNUC_MAJOR__ > 3 ||  \
                          __GNUC_MINOR__ > 2)
    #define SSE2_INTRINSICS_AVAILABLE
#endif

#endif  // X86ASM




namespace TaoCrypt {

#if defined(SSE2_INTRINSICS_AVAILABLE)

    // Allocator handling proper alignment
    template <class T>
    class AlignedAllocator : public AllocatorBase<T>
    {
    public:
        typedef typename AllocatorBase<T>::pointer   pointer;
        typedef typename AllocatorBase<T>::size_type size_type;

        pointer allocate(size_type n, const void* = 0);
        void deallocate(void* p, size_type n);
        pointer reallocate(T* p, size_type oldSize, size_type newSize,
                           bool preserve)
        {
            return StdReallocate(*this, p, oldSize, newSize, preserve);
        }

    #if !(defined(TAOCRYPT_MALLOC_ALIGNMENT_IS_16) || \
        defined(TAOCRYPT_MEMALIGN_AVAILABLE) || \
        defined(TAOCRYPT_MM_MALLOC_AVAILABLE))
    #define TAOCRYPT_NO_ALIGNED_ALLOC
        AlignedAllocator() : m_pBlock(0) {}
    protected:
        void *m_pBlock;
    #endif
    };

    typedef Block<word, AlignedAllocator<word> > AlignedWordBlock;
#else
    typedef WordBlock AlignedWordBlock;
#endif


// general MAX
template<typename T> inline
const T& max(const T& a, const T& b)
{
    return a > b ? a : b;
}


// Large Integer class
class Integer {
public:
        enum Sign {POSITIVE = 0, NEGATIVE = 1 };
        enum Signedness { UNSIGNED, SIGNED };
        enum RandomNumberType { ANY, PRIME };

        class DivideByZero {};

        Integer();
        Integer(const Integer& t);
        Integer(signed long value);
        Integer(Sign s, word highWord, word lowWord);

        // BER Decode Source
        explicit Integer(Source&);

        Integer(const byte* encodedInteger, unsigned int byteCount,
                Signedness s = UNSIGNED);

        ~Integer() {}
      
        static const Integer& Zero();
        static const Integer& One();

        Integer& Ref() { return *this; }

        Integer(RandomNumberGenerator& rng, const Integer& min,
                const Integer& max);

        static Integer Power2(unsigned int e);

        unsigned int MinEncodedSize(Signedness = UNSIGNED) const;
        unsigned int Encode(byte* output, unsigned int outputLen,
                            Signedness = UNSIGNED) const;

        void Decode(const byte* input, unsigned int inputLen,
                    Signedness = UNSIGNED);
        void Decode(Source&);

        bool  IsConvertableToLong() const;
        signed long ConvertToLong() const;

        unsigned int BitCount() const;
        unsigned int ByteCount() const;
        unsigned int WordCount() const;

        bool GetBit(unsigned int i) const;
        byte GetByte(unsigned int i) const;
        unsigned long GetBits(unsigned int i, unsigned int n) const;

        bool IsZero()      const { return !*this; }
        bool NotZero()     const { return !IsZero(); }
        bool IsNegative()  const { return sign_ == NEGATIVE; }
        bool NotNegative() const { return !IsNegative(); }
        bool IsPositive()  const { return NotNegative() && NotZero(); }
        bool NotPositive() const { return !IsPositive(); }
        bool IsEven()      const { return GetBit(0) == 0; }
        bool IsOdd()       const { return GetBit(0) == 1; }

        Integer&  operator=(const Integer& t);
        Integer&  operator+=(const Integer& t);
        Integer&  operator-=(const Integer& t);
        Integer&  operator*=(const Integer& t)	{ return *this = Times(t); }
        Integer&  operator/=(const Integer& t)	
                        { return *this = DividedBy(t);}
        Integer&  operator%=(const Integer& t)	{ return *this = Modulo(t); }
        Integer&  operator/=(word t)  { return *this = DividedBy(t); }
        Integer&  operator%=(word t)  { return *this = Modulo(t); }
        Integer&  operator<<=(unsigned int);
        Integer&  operator>>=(unsigned int);

     
        void Randomize(RandomNumberGenerator &rng, unsigned int bitcount);
        void Randomize(RandomNumberGenerator &rng, const Integer &min,
                       const Integer &max);

        void SetBit(unsigned int n, bool value = 1);
        void SetByte(unsigned int n, byte value);

        void Negate();		
        void SetPositive() { sign_ = POSITIVE; }
        void SetNegative() { if (!!(*this)) sign_ = NEGATIVE; }
        void Swap(Integer& a);

        bool	    operator!() const;
        Integer     operator+() const {return *this;}
        Integer     operator-() const;
        Integer&    operator++();
        Integer&    operator--();
        Integer     operator++(int) 
            { Integer temp = *this; ++*this; return temp; }
        Integer     operator--(int) 
            { Integer temp = *this; --*this; return temp; }

        int Compare(const Integer& a) const;

        Integer Plus(const Integer &b) const;
        Integer Minus(const Integer &b) const;
        Integer Times(const Integer &b) const;
        Integer DividedBy(const Integer &b) const;
        Integer Modulo(const Integer &b) const;
        Integer DividedBy(word b) const;
        word    Modulo(word b) const;

        Integer operator>>(unsigned int n) const { return Integer(*this)>>=n; }
        Integer operator<<(unsigned int n) const { return Integer(*this)<<=n; }

        Integer AbsoluteValue() const;
        Integer Doubled() const { return Plus(*this); }
        Integer Squared() const { return Times(*this); }
        Integer SquareRoot() const;

        bool    IsSquare() const;
        bool    IsUnit() const;

        Integer MultiplicativeInverse() const;

        friend Integer a_times_b_mod_c(const Integer& x, const Integer& y,
                                       const Integer& m);
        friend Integer a_exp_b_mod_c(const Integer& x, const Integer& e,
                                     const Integer& m);

        static void Divide(Integer& r, Integer& q, const Integer& a,
                           const Integer& d);
        static void Divide(word& r, Integer& q, const Integer& a, word d);
        static void DivideByPowerOf2(Integer& r, Integer& q, const Integer& a,
                                     unsigned int n);
        static Integer Gcd(const Integer& a, const Integer& n);

        Integer InverseMod(const Integer& n) const;
        word InverseMod(word n) const;

private:
    friend class ModularArithmetic;
    friend class MontgomeryRepresentation;

    Integer(word value, unsigned int length);
    int PositiveCompare(const Integer& t) const;

    friend void PositiveAdd(Integer& sum, const Integer& a, const Integer& b);
    friend void PositiveSubtract(Integer& diff, const Integer& a,
                                 const Integer& b);
    friend void PositiveMultiply(Integer& product, const Integer& a,
                                 const Integer& b);
    friend void PositiveDivide(Integer& remainder, Integer& quotient, const
                               Integer& dividend, const Integer& divisor);
    AlignedWordBlock reg_;
    Sign             sign_;
};

inline bool operator==(const Integer& a, const Integer& b) 
                        {return a.Compare(b)==0;}
inline bool operator!=(const Integer& a, const Integer& b) 
                        {return a.Compare(b)!=0;}
inline bool operator> (const Integer& a, const Integer& b) 
                        {return a.Compare(b)> 0;}
inline bool operator>=(const Integer& a, const Integer& b) 
                        {return a.Compare(b)>=0;}
inline bool operator< (const Integer& a, const Integer& b) 
                        {return a.Compare(b)< 0;}
inline bool operator<=(const Integer& a, const Integer& b) 
                        {return a.Compare(b)<=0;}

inline Integer operator+(const Integer &a, const Integer &b) 
                        {return a.Plus(b);}
inline Integer operator-(const Integer &a, const Integer &b) 
                        {return a.Minus(b);}
inline Integer operator*(const Integer &a, const Integer &b) 
                        {return a.Times(b);}
inline Integer operator/(const Integer &a, const Integer &b) 
                        {return a.DividedBy(b);}
inline Integer operator%(const Integer &a, const Integer &b) 
                        {return a.Modulo(b);}
inline Integer operator/(const Integer &a, word b) {return a.DividedBy(b);}
inline word    operator%(const Integer &a, word b) {return a.Modulo(b);}

inline void swap(Integer &a, Integer &b)
{
    a.Swap(b);
}


Integer CRT(const Integer& xp, const Integer& p, const Integer& xq,
            const Integer& q,  const Integer& u);

inline Integer ModularExponentiation(const Integer& a, const Integer& e,
                                     const Integer& m)
{
    return a_exp_b_mod_c(a, e, m);
}

Integer ModularRoot(const Integer& a, const Integer& dp, const Integer& dq,
                    const Integer& p, const Integer& q,  const Integer& u);



}   // namespace

#endif // TAO_CRYPT_INTEGER_HPP
