DenseLinAlgPack_IOFormat.hpp

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#ifndef LINALGPACK_IO_FORMAT_H
#define LINALGPACK_IO_FORMAT_H

#include <ios>

#include "DenseLinAlgPack_IOBasic.hpp"

namespace DenseLinAlgPack {
namespace LinAlgPackIO {

/* * This class is used to encapsulate a set of bit flags.
  */
class bit_flags {
public:

  typedef LinAlgPackIO::fmtflags fmtflags;  

  bit_flags() : flags_((fmtflags)(0x0000)) {}

  fmtflags flags() const {
    return flags_;
  }

  fmtflags flags(fmtflags f) {
    fmtflags f_tmp = flags_;
    flags_ = f;
    return f_tmp;
  }

  fmtflags setf(fmtflags f) {
    return flags( (fmtflags)(flags() | f) );
  }

  fmtflags setf(fmtflags f, fmtflags mask) {
    return flags( (fmtflags)(flags() | (f&mask)) );
  }

  void unsetf(fmtflags mask) {
    flags( (fmtflags)(flags() & ~mask) );
  }

private:
  fmtflags flags_;

};  // end class flags

/* * Memento class that saves the state of a standard stream.
  *
  * This is a variation of the "Memento" Pattern in Gama et. al.
  *
  * Allow default copy constructor and assignment operator.
  * The default constuctor is private so the only way to 
  * create an object of this class if from another object
  * or from save_format().
  */
class ios_format_memento {
public:
  static ios_format_memento save_format(const std::ios& s);

  void set_format(std::ios& s) const;

private:
  LinAlgPackIO::fmtflags  flags_;
  int       prec_;
  int       wdt_;
  int       fill_;

  ios_format_memento() : flags_((fmtflags)(0)), prec_(6), wdt_(0)
    , fill_(' ') {}

};  // end class ios_format_memento

template<class T> class bound_format;
template<class T> class const_bound_format;

/* * This class is used to allow some flexiblility in inputing
  * and outputing of DVector, DVectorSlice, DMatrix and DMatrixSlice objects.
  * It maintains format information for a #std::ios_base# object and adds
  * additional format information.
  *
  * The idea for this class is based on the user-defined manipulator given in
  * Stroustrup 1997, p. 635.  The main difference is that the non-member funciton
  * bind(format,object) is used to create a bound format object and not that
  * member function operator().  To use operator() would require a template
  * member function and they are not supposed to be allowed in MS VC++ 5.0.
  *
  * Warning: The default constructor sets the formating flags to false but this
  * may not be the default value for the actual ios stream.  It is recommended
  * that you start with the formating settings of a valid ios stream and then
  * change the flags that you want.  You can do this on construction with
  *
  * #format f(cin);#\\
  *
  * or after construction using
  *
  * #format f;#\\
  * #f.copy_format(cin);#\\
  *
  * then set the formating using the manipulator like functions.
  *
  * The default copy constructor and assignment operator functions are allowed.
  */
class format {
public:

  typedef LinAlgPackIO::fmtflags fmtflags;

  format() : prec_(6), wdt_(0), fill_(' ') {}

  format(const std::ios& s) {
    copy_format(s);
  }

  /* * @name Access format flags objects
    */
  // @{ 
  
  bit_flags& ios_base_flags()       { return ios_base_flags_; }
  const bit_flags& ios_base_flags() const { return ios_base_flags_; }

  bit_flags& extra_flags()        { return extra_flags_;  }
  const bit_flags& extra_flags() const  { return extra_flags_;  }

  // @}

  /* * @name Manipulator like functions for standard floating-point number formating.
    *
    * These member functions are ment to mirror the standard input/output
    * manipulator functions.  Their names are the same and you can set
    * a list of options in one statement like:
    *
    * #format_obj.showpos().setprecision(6).fixed();#\\
    *
    * The primary difference is that #width# presists over all uses in output
    * operations while the standard #width# manipulator only applys to the next
    * operation.  See \Ref{bound_format} and \Ref{operator>>} for details
    * on how objects of this class are used to specify formating for input/output
    * operations.
    */
  // @{

  format& showpoint()   { ios_base_flags().setf(std::ios_base::showpoint); return *this;  }
  format& noshowpoint() { ios_base_flags().unsetf(std::ios_base::showpoint); return *this;  }
  format& showpos()   { ios_base_flags().setf(std::ios_base::showpos); return *this;  }
  format& noshowpos()   { ios_base_flags().unsetf(std::ios_base::showpos); return *this;  }
  format& skipws()    { ios_base_flags().setf(std::ios_base::skipws); return *this; }
  format& noskipws()    { ios_base_flags().unsetf(std::ios_base::skipws); return *this; }
  format& uppercase()   { ios_base_flags().setf(std::ios_base::uppercase); return *this;  }
  format& nouppercase() { ios_base_flags().unsetf(std::ios_base::uppercase); return *this;  }
  format& internal()    {
    ios_base_flags().setf(std::ios_base::internal, std::ios_base::adjustfield);
    return *this;
  }
  format& left()      {
    ios_base_flags().setf(std::ios_base::left, std::ios_base::adjustfield);
    return *this;
  }
  format& right()     {
    ios_base_flags().setf(std::ios_base::right, std::ios_base::adjustfield);
    return *this;
  }
  format& general()   {
    ios_base_flags().setf((fmtflags)0, std::ios_base::floatfield);
    return *this;
  }
  format& fixed()     {
    ios_base_flags().setf(std::ios_base::fixed, std::ios_base::floatfield);
    return *this;
  }
  format& scientific()  {
    ios_base_flags().setf(std::ios_base::scientific, std::ios_base::floatfield);
    return *this;
  }
  format& setfill(int c)  { fill_ = c; return *this;  }
  format& setprecision(int p) { prec_ = p; return *this;  }
  format& setw(int w)   { wdt_ = w; return *this; }

  // @}

  /* * @name Manipulator like functions for extra I/O formatin.
    *
    * These member functions are ment to mirror the type of standard input/output
    * manipulator functions accept they are used to set extra flags for 
    * #DenseLinAlgPack::ignore_dim_bit# and #DenseLinAlgPack::no_insert_newlines_bit#.
    * This allows them to be set in the same statement that sets a standard
    * option.  For example you can write:
    *
    * #format_obj.showpos().setprecision(6).fixed().ignore_dim().no_insert_newlines();#\\
    *
    * Like the member functions that simulate the standard manipulators these
    * options presist after input/output operations.
    */
  // @{

  format& ignore_dim()
  {
    extra_flags().setf((fmtflags)(ignore_dim_bit));
    return *this;
  }
  format& no_ignore_dim()
  {
    extra_flags().unsetf((fmtflags)(ignore_dim_bit));
    return *this;
  }
  format& insert_newlines()
  {
    extra_flags().unsetf((fmtflags)(no_insert_newlines_bit));
    return *this;
  }
  format& no_insert_newlines()
  {
    extra_flags().setf((fmtflags)(no_insert_newlines_bit));
    return *this;
  }

  // @}

  /* * @name Other access functions
    */
  // @{

  int precision() const     { return prec_; }
  int precision(int p)      { int tmp = prec_; prec_ = p; return tmp; }
  int width() const       { return wdt_;  }
  int width(int w)        { int tmp = wdt_; wdt_ = w; return tmp; }
  int fill() const        { return fill_; }
  int fill(int c)         { int tmp = fill_; fill_ = c; return tmp; }

  // @}

  /* * @name Utility functions for saving and replacing a streams format state
    */
  // @{

  void copy_format(const std::ios& s);

  void set_format(std::ios& s) const;
  
  // @}


// ToDo: Enable these once member templates are supported.  This is much more
// attractive syntasticaly than using bind() and cbind() 
//
//  ///
//  template<class T>
//  bound_format<T> operator()(T& obj);
//
//  ///
//  template<class T>
//  const_bound_format<T> operator()(const T& obj) const;

private:
  bit_flags ios_base_flags_;
  bit_flags extra_flags_;
  int prec_;
  int wdt_;
  int fill_;

};  // end class LinAlgPackIOFormat


// ////////////////////////////////////////////////////////////////////////////////
// Format binding classes and functions

template<class T> class const_bound_format;

/* * Special I/O manipulator class for non-constant objects.
  *
  * This class as a special manipulator and is composed of a composition
  * of a format object and a templated object that is used in an input
  * or output operation.
  *
  * An object of this class should only be created by using 
  * the bind(format,obj) function.  It object can not default constructed
  * or assigned.
  *
  * Objects of this class can be implicitly converted to const_bound_format
  * for use in output operations.
  */
template<class T>
class bound_format {
public:

  bound_format(const format& f, T& obj) : f_(f), obj_(obj) {}

  const format& f() const { return f_; }
  T&  obj()       { return obj_; }
  const T& obj() const  { return obj_; }
  
private:
  const format& f_;
  T&        obj_;

  // not defined and not to be called
  bound_format();
  bound_format& operator=(const bound_format&);

};  // end class bound_format

/* * Special I/O manipulator class for constant objects.
  *
  * This class as a special manipulator and is composed of a composition
  * of a format object and a const templated object that is used only in
  * an output operation.
  *
  * An object of this class can only be created by using 
  * the bind(f,obj) operation.  It can not be default constructed or assigned.
  * It is only to be used in input or output operations.
  */
template<class T>
class const_bound_format {
public:

  const_bound_format(const format& f, const T& obj) : f_(f), obj_(obj) {}

  const_bound_format(const bound_format<T>& bf) : f_(bf.f()), obj_(bf.obj()) {}

  const format& f() const { return f_; }
  const T& obj() const  { return obj_; }

private:
  const format& f_;
  const T&    obj_;

  // not defined and not to be called
  const_bound_format();
  const_bound_format& operator=(const const_bound_format&);

};  // end class const_bound_format

/* * Returns a bound_format<T> object using this format object.
  *
  * Using templated input/output operator functions this function
  * is used to bind a format to a non-const target object for a
  * input/output stream operation.  For example, to bind the format 
  * for a single output operation using the streams set formating 
  * and addition formating use something like:
  *
  * #DVector v(1.0,5);#\\
  * #format f; f.copy_format(cout);#\\
  * #f.width(10).fixed().ignore_dim();#\\
  * #cout << bind(f,v);#\\1
  */
template<class T>
inline bound_format<T> bind(const format& f, T& obj) {
  return bound_format<T>(f,obj);
}

/* * Returns a const_bound_format<T> using this format object.
  *
  * This function works the same as the previous \Ref{bind}#()# function
  * accept it is for a const target object.  It could not use
  * the name #bind# due to ambiguity problems.
  */
template<class T>
inline const_bound_format<T> cbind(const format& f, const T& obj) {
  return const_bound_format<T>(f,obj);
}

// ///////////////////////////////////////
// Inline functions for members of format

// Use once member templates are supported.  See class format
//
//template<class T>
//inline bound_format<T> format::operator()(T& obj) {
//  return bind(*this,obj);
//}

//template<class T>
//inline const_bound_format<T> format::operator()(const T& obj) const {
//  return cbind(*this,obj);
//}

} // end namespace LinAlgPackIO
} // end namespace DenseLinAlgPack

#endif // LINALGPACK_IO_FORMAT_H