1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
5// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
6//
7// This Source Code Form is subject to the terms of the Mozilla
8// Public License v. 2.0. If a copy of the MPL was not distributed
9// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
10
11#ifndef EIGEN_IO_H
12#define EIGEN_IO_H
13
14namespace Eigen {
15
16enum { DontAlignCols = 1 };
17enum { StreamPrecision = -1,
18       FullPrecision = -2 };
19
20namespace internal {
21template<typename Derived>
22std::ostream & print_matrix(std::ostream & s, const Derived& _m, const IOFormat& fmt);
23}
24
25/** \class IOFormat
26  * \ingroup Core_Module
27  *
28  * \brief Stores a set of parameters controlling the way matrices are printed
29  *
30  * List of available parameters:
31  *  - \b precision number of digits for floating point values, or one of the special constants \c StreamPrecision and \c FullPrecision.
32  *                 The default is the special value \c StreamPrecision which means to use the
33  *                 stream's own precision setting, as set for instance using \c cout.precision(3). The other special value
34  *                 \c FullPrecision means that the number of digits will be computed to match the full precision of each floating-point
35  *                 type.
36  *  - \b flags an OR-ed combination of flags, the default value is 0, the only currently available flag is \c DontAlignCols which
37  *             allows to disable the alignment of columns, resulting in faster code.
38  *  - \b coeffSeparator string printed between two coefficients of the same row
39  *  - \b rowSeparator string printed between two rows
40  *  - \b rowPrefix string printed at the beginning of each row
41  *  - \b rowSuffix string printed at the end of each row
42  *  - \b matPrefix string printed at the beginning of the matrix
43  *  - \b matSuffix string printed at the end of the matrix
44  *
45  * Example: \include IOFormat.cpp
46  * Output: \verbinclude IOFormat.out
47  *
48  * \sa DenseBase::format(), class WithFormat
49  */
50struct IOFormat
51{
52  /** Default constructor, see class IOFormat for the meaning of the parameters */
53  IOFormat(int _precision = StreamPrecision, int _flags = 0,
54    const std::string& _coeffSeparator = " ",
55    const std::string& _rowSeparator = "\n", const std::string& _rowPrefix="", const std::string& _rowSuffix="",
56    const std::string& _matPrefix="", const std::string& _matSuffix="")
57  : matPrefix(_matPrefix), matSuffix(_matSuffix), rowPrefix(_rowPrefix), rowSuffix(_rowSuffix), rowSeparator(_rowSeparator),
58    rowSpacer(""), coeffSeparator(_coeffSeparator), precision(_precision), flags(_flags)
59  {
60    // TODO check if rowPrefix, rowSuffix or rowSeparator contains a newline
61    // don't add rowSpacer if columns are not to be aligned
62    if((flags & DontAlignCols))
63      return;
64    int i = int(matSuffix.length())-1;
65    while (i>=0 && matSuffix[i]!='\n')
66    {
67      rowSpacer += ' ';
68      i--;
69    }
70  }
71  std::string matPrefix, matSuffix;
72  std::string rowPrefix, rowSuffix, rowSeparator, rowSpacer;
73  std::string coeffSeparator;
74  int precision;
75  int flags;
76};
77
78/** \class WithFormat
79  * \ingroup Core_Module
80  *
81  * \brief Pseudo expression providing matrix output with given format
82  *
83  * \tparam ExpressionType the type of the object on which IO stream operations are performed
84  *
85  * This class represents an expression with stream operators controlled by a given IOFormat.
86  * It is the return type of DenseBase::format()
87  * and most of the time this is the only way it is used.
88  *
89  * See class IOFormat for some examples.
90  *
91  * \sa DenseBase::format(), class IOFormat
92  */
93template<typename ExpressionType>
94class WithFormat
95{
96  public:
97
98    WithFormat(const ExpressionType& matrix, const IOFormat& format)
99      : m_matrix(matrix), m_format(format)
100    {}
101
102    friend std::ostream & operator << (std::ostream & s, const WithFormat& wf)
103    {
104      return internal::print_matrix(s, wf.m_matrix.eval(), wf.m_format);
105    }
106
107  protected:
108    typename ExpressionType::Nested m_matrix;
109    IOFormat m_format;
110};
111
112namespace internal {
113
114// NOTE: This helper is kept for backward compatibility with previous code specializing
115//       this internal::significant_decimals_impl structure. In the future we should directly
116//       call digits10() which has been introduced in July 2016 in 3.3.
117template<typename Scalar>
118struct significant_decimals_impl
119{
120  static inline int run()
121  {
122    return NumTraits<Scalar>::digits10();
123  }
124};
125
126/** \internal
127  * print the matrix \a _m to the output stream \a s using the output format \a fmt */
128template<typename Derived>
129std::ostream & print_matrix(std::ostream & s, const Derived& _m, const IOFormat& fmt)
130{
131  if(_m.size() == 0)
132  {
133    s << fmt.matPrefix << fmt.matSuffix;
134    return s;
135  }
136
137  typename Derived::Nested m = _m;
138  typedef typename Derived::Scalar Scalar;
139
140  Index width = 0;
141
142  std::streamsize explicit_precision;
143  if(fmt.precision == StreamPrecision)
144  {
145    explicit_precision = 0;
146  }
147  else if(fmt.precision == FullPrecision)
148  {
149    if (NumTraits<Scalar>::IsInteger)
150    {
151      explicit_precision = 0;
152    }
153    else
154    {
155      explicit_precision = significant_decimals_impl<Scalar>::run();
156    }
157  }
158  else
159  {
160    explicit_precision = fmt.precision;
161  }
162
163  std::streamsize old_precision = 0;
164  if(explicit_precision) old_precision = s.precision(explicit_precision);
165
166  bool align_cols = !(fmt.flags & DontAlignCols);
167  if(align_cols)
168  {
169    // compute the largest width
170    for(Index j = 0; j < m.cols(); ++j)
171      for(Index i = 0; i < m.rows(); ++i)
172      {
173        std::stringstream sstr;
174        sstr.copyfmt(s);
175        sstr << m.coeff(i,j);
176        width = std::max<Index>(width, Index(sstr.str().length()));
177      }
178  }
179  s << fmt.matPrefix;
180  for(Index i = 0; i < m.rows(); ++i)
181  {
182    if (i)
183      s << fmt.rowSpacer;
184    s << fmt.rowPrefix;
185    if(width) s.width(width);
186    s << m.coeff(i, 0);
187    for(Index j = 1; j < m.cols(); ++j)
188    {
189      s << fmt.coeffSeparator;
190      if (width) s.width(width);
191      s << m.coeff(i, j);
192    }
193    s << fmt.rowSuffix;
194    if( i < m.rows() - 1)
195      s << fmt.rowSeparator;
196  }
197  s << fmt.matSuffix;
198  if(explicit_precision) s.precision(old_precision);
199  return s;
200}
201
202} // end namespace internal
203
204/** \relates DenseBase
205  *
206  * Outputs the matrix, to the given stream.
207  *
208  * If you wish to print the matrix with a format different than the default, use DenseBase::format().
209  *
210  * It is also possible to change the default format by defining EIGEN_DEFAULT_IO_FORMAT before including Eigen headers.
211  * If not defined, this will automatically be defined to Eigen::IOFormat(), that is the Eigen::IOFormat with default parameters.
212  *
213  * \sa DenseBase::format()
214  */
215template<typename Derived>
216std::ostream & operator <<
217(std::ostream & s,
218 const DenseBase<Derived> & m)
219{
220  return internal::print_matrix(s, m.eval(), EIGEN_DEFAULT_IO_FORMAT);
221}
222
223} // end namespace Eigen
224
225#endif // EIGEN_IO_H
226