internal::BigInteger Class Reference

#include <biginteger.h>

Public Types
typedef uint64_t	Type

Public Member Functions
	BigInteger (const BigInteger &rhs)
	BigInteger (uint64_t u)
	BigInteger (const char *decimals, size_t length)
BigInteger &	operator= (const BigInteger &rhs)
BigInteger &	operator= (uint64_t u)
BigInteger &	operator+= (uint64_t u)
BigInteger &	operator*= (uint64_t u)
BigInteger &	operator*= (uint32_t u)
BigInteger &	operator<<= (size_t shift)
bool	operator== (const BigInteger &rhs) const
bool	operator== (const Type rhs) const
BigInteger &	MultiplyPow5 (unsigned exp)
bool	Difference (const BigInteger &rhs, BigInteger *out) const
int	Compare (const BigInteger &rhs) const
size_t	GetCount () const
Type	GetDigit (size_t index) const
bool	IsZero () const

Detailed Description

Definition at line 28 of file biginteger.h.

Member Typedef Documentation

Type

uint64_t internal::BigInteger::Type

Definition at line 30 of file biginteger.h.

Constructor & Destructor Documentation

BigInteger() [1/3]

internal::BigInteger::BigInteger ( const BigInteger & rhs )

inline

Definition at line 32 of file biginteger.h.

                                      : count_(rhs.count_) {
        std::memcpy(digits_, rhs.digits_, count_ * sizeof(Type));
    }

BigInteger() [2/3]

internal::BigInteger::BigInteger ( uint64_t u )

inlineexplicit

Definition at line 36 of file biginteger.h.

                                    : count_(1) {
        digits_[0] = u;
    }

BigInteger() [3/3]

internal::BigInteger::BigInteger ( const char * decimals, size_t length )

inline

Definition at line 40 of file biginteger.h.

                                                    : count_(1) {
        RAPIDJSON_ASSERT(length > 0);
        digits_[0] = 0;
        size_t i = 0;
        const size_t kMaxDigitPerIteration = 19;  // 2^64 = 18446744073709551616 > 10^19
        while (length >= kMaxDigitPerIteration) {
            AppendDecimal64(decimals + i, decimals + i + kMaxDigitPerIteration);
            length -= kMaxDigitPerIteration;
            i += kMaxDigitPerIteration;
        }
 
        if (length > 0)
            AppendDecimal64(decimals + i, decimals + i + length);
    }

Member Function Documentation

Compare()

int internal::BigInteger::Compare ( const BigInteger & rhs ) const

inline

Definition at line 208 of file biginteger.h.

                                             {
        if (count_ != rhs.count_)
            return count_ < rhs.count_ ? -1 : 1;
 
        for (size_t i = count_; i-- > 0;)
            if (digits_[i] != rhs.digits_[i])
                return digits_[i] < rhs.digits_[i] ? -1 : 1;
 
        return 0;
    }

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Difference()

bool internal::BigInteger::Difference ( const BigInteger & rhs, BigInteger * out ) const

inline

Definition at line 186 of file biginteger.h.

                                                                  {
        int cmp = Compare(rhs);
        RAPIDJSON_ASSERT(cmp != 0);
        const BigInteger *a, *b;  // Makes a > b
        bool ret;
        if (cmp < 0) { a = &rhs; b = this; ret = true; }
        else         { a = this; b = &rhs; ret = false; }
 
        Type borrow = 0;
        for (size_t i = 0; i < a->count_; i++) {
            Type d = a->digits_[i] - borrow;
            if (i < b->count_)
                d -= b->digits_[i];
            borrow = (d > a->digits_[i]) ? 1 : 0;
            out->digits_[i] = d;
            if (d != 0)
                out->count_ = i + 1;
        }
 
        return ret;
    }

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GetCount()

size_t internal::BigInteger::GetCount ( ) const

inline

Definition at line 219 of file biginteger.h.

{ return count_; }

GetDigit()

Type internal::BigInteger::GetDigit ( size_t index ) const

inline

Definition at line 220 of file biginteger.h.

{ RAPIDJSON_ASSERT(index < count_); return digits_[index]; }

IsZero()

bool internal::BigInteger::IsZero ( ) const

inline

Definition at line 221 of file biginteger.h.

{ return count_ == 1 && digits_[0] == 0; }

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MultiplyPow5()

BigInteger & internal::BigInteger::MultiplyPow5 ( unsigned exp )

inline

Definition at line 162 of file biginteger.h.

                                           {
        static const uint32_t kPow5[12] = {
            5,
            5 * 5,
            5 * 5 * 5,
            5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5,
            5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5
        };
        if (exp == 0) return *this;
        for (; exp >= 27; exp -= 27) *this *= RAPIDJSON_UINT64_C2(0X6765C793, 0XFA10079D); // 5^27
        for (; exp >= 13; exp -= 13) *this *= static_cast<uint32_t>(1220703125u); // 5^13
        if (exp > 0)                 *this *= kPow5[exp - 1];
        return *this;
    }

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operator*=() [1/2]

BigInteger & internal::BigInteger::operator*= ( uint32_t u )

inline

Definition at line 105 of file biginteger.h.

                                       {
        if (u == 0) return *this = 0;
        if (u == 1) return *this;
        if (*this == 1) return *this = u;
 
        uint64_t k = 0;
        for (size_t i = 0; i < count_; i++) {
            const uint64_t c = digits_[i] >> 32;
            const uint64_t d = digits_[i] & 0xFFFFFFFF;
            const uint64_t uc = u * c;
            const uint64_t ud = u * d;
            const uint64_t p0 = ud + k;
            const uint64_t p1 = uc + (p0 >> 32);
            digits_[i] = (p0 & 0xFFFFFFFF) | (p1 << 32);
            k = p1 >> 32;
        }
        
        if (k > 0)
            PushBack(k);
 
        return *this;
    }

operator*=() [2/2]

BigInteger & internal::BigInteger::operator*= ( uint64_t u )

inline

Definition at line 87 of file biginteger.h.

                                       {
        if (u == 0) return *this = 0;
        if (u == 1) return *this;
        if (*this == 1) return *this = u;
 
        uint64_t k = 0;
        for (size_t i = 0; i < count_; i++) {
            uint64_t hi;
            digits_[i] = MulAdd64(digits_[i], u, k, &hi);
            k = hi;
        }
        
        if (k > 0)
            PushBack(k);
 
        return *this;
    }

operator+=()

BigInteger & internal::BigInteger::operator+= ( uint64_t u )

inline

Definition at line 70 of file biginteger.h.

                                       {
        Type backup = digits_[0];
        digits_[0] += u;
        for (size_t i = 0; i < count_ - 1; i++) {
            if (digits_[i] >= backup)
                return *this; // no carry
            backup = digits_[i + 1];
            digits_[i + 1] += 1;
        }
 
        // Last carry
        if (digits_[count_ - 1] < backup)
            PushBack(1);
 
        return *this;
    }

operator<<=()

BigInteger & internal::BigInteger::operator<<= ( size_t shift )

inline

Definition at line 128 of file biginteger.h.

                                          {
        if (IsZero() || shift == 0) return *this;
 
        size_t offset = shift / kTypeBit;
        size_t interShift = shift % kTypeBit;
        RAPIDJSON_ASSERT(count_ + offset <= kCapacity);
 
        if (interShift == 0) {
            std::memmove(digits_ + offset, digits_, count_ * sizeof(Type));
            count_ += offset;
        }
        else {
            digits_[count_] = 0;
            for (size_t i = count_; i > 0; i--)
                digits_[i + offset] = (digits_[i] << interShift) | (digits_[i - 1] >> (kTypeBit - interShift));
            digits_[offset] = digits_[0] << interShift;
            count_ += offset;
            if (digits_[count_])
                count_++;
        }
 
        std::memset(digits_, 0, offset * sizeof(Type));
 
        return *this;
    }

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operator=() [1/2]

BigInteger & internal::BigInteger::operator= ( const BigInteger & rhs )

inline

Definition at line 55 of file biginteger.h.

    {
        if (this != &rhs) {
            count_ = rhs.count_;
            std::memcpy(digits_, rhs.digits_, count_ * sizeof(Type));
        }
        return *this;
    }

operator=() [2/2]

BigInteger & internal::BigInteger::operator= ( uint64_t u )

inline

Definition at line 64 of file biginteger.h.

                                      {
        digits_[0] = u;            
        count_ = 1;
        return *this;
    }

operator==() [1/2]

bool internal::BigInteger::operator== ( const BigInteger & rhs ) const

inline

Definition at line 154 of file biginteger.h.

                                                 {
        return count_ == rhs.count_ && std::memcmp(digits_, rhs.digits_, count_ * sizeof(Type)) == 0;
    }

operator==() [2/2]

bool internal::BigInteger::operator== ( const Type rhs ) const

inline

Definition at line 158 of file biginteger.h.

                                          {
        return count_ == 1 && digits_[0] == rhs;
    }

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The documentation for this class was generated from the following file:

• libraries/fc/include/fc/crypto/webauthn_json/include/rapidjson/internal/biginteger.h