vnl_bignum.cxx

InsightToolkit-1.4.0(有大量的优化算法程序)

  rt_pos = 0;
  char c = next(s,is);
  while (c == ' ' || c == '\t' || c == '\n' || c == '\r') c = next(s,is);
  if (c == '+' || c == '-') c = next(s,is);
  if (c != '0') return false;
  while (c >= '0' && c <= '7') c = next(s,is);
  if (c == 'l' || c == 'L') c = next(s,is);
  if (rt_pos > 0) rt[++rt_pos] = '\0';
  return is ? true : c == '\0';
}
static bool is_plus_inf(const char* s, vcl_istream** is = 0)
{
  rt_pos = 0;
  char c = next(s,is);
  while (c == ' ' || c == '\t' || c == '\n' || c == '\r') c = next(s,is);
  if (c == '+') c = next(s,is);
  if (c != 'I') return false; c = next(s,is);
  if (c != 'n') return false; c = next(s,is);
  if (c != 'f') return false; c = next(s,is);
  if (c == 'i') c = next(s,is);
  if (c == 'n') c = next(s,is);
  if (c == 'i') c = next(s,is);
  if (c == 't') c = next(s,is);
  if (c == 'y') c = next(s,is);
  if (rt_pos > 0) rt[++rt_pos] = '\0';
  return is ? true : c == '\0';
}
static bool is_minus_inf(const char* s, vcl_istream** is = 0)
{
  rt_pos = 0;
  char c = next(s,is);
  while (c == ' ' || c == '\t' || c == '\n' || c == '\r') c = next(s,is);
  if (c != '-') return false; c = next(s,is);
  if (c != 'I') return false; c = next(s,is);
  if (c != 'n') return false; c = next(s,is);
  if (c != 'f') return false; c = next(s,is);
  if (c == 'i') c = next(s,is);
  if (c == 'n') c = next(s,is);
  if (c == 'i') c = next(s,is);
  if (c == 't') c = next(s,is);
  if (c == 'y') c = next(s,is);
  if (rt_pos > 0) rt[++rt_pos] = '\0';
  return is ? true : c == '\0';
}

#endif // new implementation - PVr

//: Creates a vnl_bignum from the character string representation.

vnl_bignum::vnl_bignum (const char *s)
: count(0), sign(1), data(0)
{
  // decimal:     "^ *[-+]?[1-9][0-9]*$"
  // exponential: "^ *[-+]?[1-9][0-9]*[eE][+]?[0-9]+$"
  // hexadecimal: "^ *[-+]?0[xX][0-9a-fA-F]+$"
  // octal:       "^ *[-+]?0[0-7]*$"
  // infinity:    "^ *[-+]?Inf(inity)?$"

  if (is_plus_inf(s))
    sign=1,count=1,data=new Data[1],data[0]=0;
  else if (is_minus_inf(s))
    sign=-1,count=1,data=new Data[1],data[0]=0;
  else if (is_decimal(s))               // If string is decimal
    this->dtoBigNum(s);                 // convert decimal to vnl_bignum
  else if (is_exponential(s))           // If string is exponential
    this->exptoBigNum(s);               // convert exp. to vnl_bignum
  else if (is_hexadecimal(s))           // If string is hex,
    this->xtoBigNum(s);                 // convert hex to vnl_bignum
  else if (is_octal(s))                 // If string is octal
    this->otoBigNum(s);                 // convert octal to vnl_bignum
  else {                                // Otherwise
    vcl_cerr << "Cannot convert string " << s << " to vnl_bignum\n";
  }
}

//: Reads a vnl_bignum from a stream

vcl_istream& operator>> (vcl_istream& is, vnl_bignum& x)
{
  // decimal:     "^ *[-+]?[1-9][0-9]*$"
  // exponential: "^ *[-+]?[1-9][0-9]*[eE][+]?[0-9]+$"
  // hexadecimal: "^ *[-+]?0[xX][0-9a-fA-F]+$"
  // octal:       "^ *[-+]?0[0-7]*$"
  vcl_istream* isp = &is;
  rt[0] = '\0';

  if (is_plus_inf(rt,&isp))
    x.sign=1,x.count=1,x.data=new Data[1],x.data[0]=0;
  else if (is_minus_inf(rt,&isp))
    x.sign=-1,x.count=1,x.data=new Data[1],x.data[0]=0;
  if (is_exponential(rt,&isp))          // If input stream string is exponential
    x.exptoBigNum(rt);                  // convert exp. to vnl_bignum
  else if (is_decimal(rt,&isp))         // If string is decimal
    x.dtoBigNum(rt);                    // convert decimal to vnl_bignum
  else if (is_hexadecimal(rt,&isp))     // If string is hex,
    x.xtoBigNum(rt);                    // convert hex to vnl_bignum
  else if (is_octal(rt,&isp))           // If string is octal
    x.otoBigNum(rt);                    // convert octal to vnl_bignum
  else {                                // Otherwise
    vcl_cerr << "Cannot convert string " << rt << " to vnl_bignum\n";
    x = 0L;
  }
  return is; // FIXME - should probably push back read characters to istream
}

//: Copies the contents of vnl_bignum b.

vnl_bignum::vnl_bignum (const vnl_bignum& b)
: count(b.count), sign(b.sign)
{
  this->data = b.data ? new Data[b.count] : 0;  // Allocate data if necessary
  for (Counter i = 0; i < this->count; ++i)     // Copy b data
    this->data[i] = b.data[i];
}


//: Frees space for vnl_bignum.

vnl_bignum::~vnl_bignum ()
{
  delete [] this->data; this->count = 0;        // Delete any allocated data
}

//: Copies rhs vnl_bignum to lhs vnl_bignum.

vnl_bignum& vnl_bignum::operator= (const vnl_bignum& rhs)
{
  if (this != &rhs) {                           // Avoid self-assignment
    delete [] this->data;                       // Delete existing data
    this->count = rhs.count;                    // Copy rhs's count
    this->data = rhs.data ? new Data[rhs.count] : 0; // Allocate data if necessary
    for (Counter i = 0; i < rhs.count; ++i)     // Copy rhs's data
      this->data[i] = rhs.data[i];
    this->sign = rhs.sign;                      // Copy rhs's sign
  }
  return *this;                                 // Return reference
}

//: Returns the negation of a vnl_bignum.

vnl_bignum vnl_bignum::operator- () const
{
  vnl_bignum neg(*this);
  if (neg.count)                // So long as this is non-zero
    neg.sign = -neg.sign;       // Flip its sign
  return neg;
}


//: Prefix increment. Increments a vnl_bignum by 1, and returns it.

vnl_bignum& vnl_bignum::operator++ ()
{
  return *this = *this + 1L;
}


//: Prefix decrement. Decrements a vnl_bignum by 1, and returns it.

vnl_bignum& vnl_bignum::operator-- ()
{
  return *this = *this - 1L;
}

//: Adds two vnl_bignums, and returns new sum.

vnl_bignum vnl_bignum::operator+(const vnl_bignum& b) const
{
  // Infinity arithmetic:
  assert (! b.is_minus_infinity() || ! this->is_plus_infinity() ); // +Inf-Inf
  assert (! b.is_plus_infinity() || ! this->is_minus_infinity() ); // -Inf+Inf
  if (b.is_infinity()) { return b; }
  if (this->is_infinity()) { return *this; }

  vnl_bignum sum;                       // Init sum to zero
  if (this->sign == b.sign) {           // If both have same sign
    add(*this,b,sum);                   //   Do simple addition
    sum.sign = this->sign;              // Attach proper sign
  }
  else {                                // Else different signs
    int mag = magnitude_cmp(*this,b);   // Determine relative sizes
    if (mag > 0) {                      // If abs(*this) > abs(b)
      subtract(*this,b,sum);            //   sum = *this - b
      sum.sign = this->sign;            // Sign of sum follows *this
    }
    else if (mag < 0) {                 // Else if abs(*this) < abs(b)
      subtract(b,*this,sum);            //   sum = b - *this
      sum.sign = b.sign;                // Sign of sum follows b
    }                                   // (Else abs(*this) == abs(b)
  }                                     //   so sum must be zero)
  return sum;                           // shallow swap on return
}


//: Multiplies this with a vnl_bignum

vnl_bignum& vnl_bignum::operator*= (const vnl_bignum& b)
{
  // Infinity arithmetic:
  assert (! b.is_infinity() || this->count != 0 ); // multiplication 0*Inf
  assert (! this->is_infinity() || b.count != 0 ); // multiplication Inf*0
  if (b.is_infinity()) return (*this) = (this->sign<0 ? -b : b);
  if (this->is_infinity()) return (*this) = (b.sign<0 ? -(*this) : *this);

  if (b.count == 0 || this->count == 0)
    return (*this)=0L;
  vnl_bignum prod;
  prod.data = new Data[prod.count = this->count + b.count]; // allocate data for product
  for (Counter i = 0; i < b.count; i++)         //   multiply each b "digit"
    multiply_aux(*this, b.data[i], prod, i);    //   times b1 and add to total
  prod.sign = this->sign * b.sign;              //   determine correct sign
  prod.trim();                                  //   trim excess data and ret.
  return (*this)=prod;
}


//: Divides this by a vnl_bignum

vnl_bignum& vnl_bignum::operator/= (const vnl_bignum& b)
{
  // Infinity arithmetic:
  assert (! b.is_infinity() || ! this->is_infinity() ); // division Inf/Inf
  if (b.is_infinity()) return (*this)=0L;
  if (this->is_infinity()) return (*this) = (b.sign<0 ? -(*this) : *this);
  assert (b.count!=0 || this->count != 0); // division 0/0
  if (b.count == 0)
    return (*this) = (this->sign < 0 ? vnl_bignum("-Inf") : vnl_bignum("+Inf"));

  vnl_bignum quot, r;          // Quotient and remainder
  divide(*this,b,quot,r);      // Call divide fn
  return (*this) = quot;
}

//: Divides this by a vnl_bignum and replaces this by remainder.

vnl_bignum& vnl_bignum::operator%= (const vnl_bignum& b)
{
  // Infinity arithmetic:
  assert (! b.is_infinity() || ! this->is_infinity() ); // division Inf/Inf
  if (b.is_infinity()) return *this;                    // remainder of x/Inf is x.
  if (this->is_infinity()) return (*this) = 0L;         // convention: remainder is 0
  assert (b.count!=0 || this->count != 0);              // division 0/0
  if (b.count == 0) return (*this) = 0L;                // convention: remainder is 0

  vnl_bignum remain, q;        // Quotient and remainder
  divide(*this,b,q,remain);    // divide by b and save remainder
  return (*this) = remain;     // shallow swap on return
}


//: Shifts bignum to the left l digits.

vnl_bignum vnl_bignum::operator<< (int l) const
{
  // Infinity arithmetic:
  if (this->is_infinity()) return *this;

  if (l == 0 || *this == 0L)            // if either arg is zero
    return *this;
  if (l < 0)                            // if shift amt is negative
    return right_shift(*this,-l);       //   do an actual right shift
  else                                  // otherwise
    return left_shift(*this,l);         //   do a left shift
}


//: Shifts bignum to the right l digits.

vnl_bignum vnl_bignum::operator>> (int l) const
{
  // Infinity arithmetic:
  if (this->is_infinity()) return *this;

  if (l == 0 || *this == 0L)            // if either arg is zero
    return *this;
  if (l < 0)                            // if shift amt is negative
    return left_shift(*this,-l);        //   do an actual left shift
  else                                  // else
    return right_shift(*this,l);        //   do a right shift
}


//: Two vnl_bignums are equal if and only if they have the same integer representation.

bool vnl_bignum::operator== (const vnl_bignum& rhs) const
{
  if (this != &rhs) {                           // Check address
    if (this->sign != rhs.sign) return false;   // Different sign implies !=
    if (this->count != rhs.count) return false; // Different size implies !=
    for (Counter i = 0; i < this->count; i++)   // Each data element the same?
      if (this->data[i] != rhs.data[i]) return false; // No. Return !=
  }
  return true;                                    // Yes. Return ==
}


//: Compares two vnl_bignums.

bool vnl_bignum::operator< (const vnl_bignum& rhs) const
{
  if (this->sign < rhs.sign) return true;       // Different signs?
  if (this->sign > rhs.sign) return false;
  if (this->sign == 1)                          // Both signs == 1
    return magnitude_cmp(*this,rhs) < 0;        // this must be smaller
  else                                          // Both signs == -1
    return magnitude_cmp(*this,rhs) > 0;        // this must be larger
}


//: Formatted output for bignum.

vcl_ostream& operator<< (vcl_ostream& os, const vnl_bignum& b)
{
  vnl_bignum d = b;                     // Copy the input vnl_bignum
  if (d.sign == -1) {                   // If it's negative
    os << '-';                          //   Output leading minus sign
    d.sign = 1;                         //   Make d positive for divide
  }
  if (d.is_infinity()) return os<<"Inf";
  vnl_bignum q,r;                       // Temp quotient and remainder
  char *cbuf = new char[5 * (b.count+1)];   // Temp character buffer