libstdc++-v3/include/bits/stl_numeric.h

   1 // Numeric functions implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /*
  27  *
  28  * Copyright (c) 1994
  29  * Hewlett-Packard Company
  30  *
  31  * Permission to use, copy, modify, distribute and sell this software
  32  * and its documentation for any purpose is hereby granted without fee,
  33  * provided that the above copyright notice appear in all copies and
  34  * that both that copyright notice and this permission notice appear
  35  * in supporting documentation.  Hewlett-Packard Company makes no
  36  * representations about the suitability of this software for any
  37  * purpose.  It is provided "as is" without express or implied warranty.
  38  *
  39  *
  40  * Copyright (c) 1996,1997
  41  * Silicon Graphics Computer Systems, Inc.
  42  *
  43  * Permission to use, copy, modify, distribute and sell this software
  44  * and its documentation for any purpose is hereby granted without fee,
  45  * provided that the above copyright notice appear in all copies and
  46  * that both that copyright notice and this permission notice appear
  47  * in supporting documentation.  Silicon Graphics makes no
  48  * representations about the suitability of this software for any
  49  * purpose.  It is provided "as is" without express or implied warranty.
  50  */
  51
  52 /** @file bits/stl_numeric.h
  53  *  This is an internal header file, included by other library headers.
  54  *  Do not attempt to use it directly. @headername{numeric}
  55  */
  56
  57 #ifndef _STL_NUMERIC_H
  58 #define _STL_NUMERIC_H 1
  59
  60 #include <bits/concept_check.h>
  61 #include <debug/debug.h>
  62 #include <bits/move.h> // For _GLIBCXX_MOVE
  63
  64 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  65
  66 _GLIBCXX_BEGIN_NAMESPACE(std)
  67
  68   /**
  69    *  @brief  Create a range of sequentially increasing values.
  70    *
  71    *  For each element in the range @p [first,last) assigns @p value and
  72    *  increments @p value as if by @p ++value.
  73    *
  74    *  @param  first  Start of range.
  75    *  @param  last  End of range.
  76    *  @param  value  Starting value.
  77    *  @return  Nothing.
  78    */
  79   template<typename _ForwardIterator, typename _Tp>
  80     void
  81     iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value)
  82     {
  83       // concept requirements
  84       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
  85                                   _ForwardIterator>)
  86       __glibcxx_function_requires(_ConvertibleConcept<_Tp,
  87             typename iterator_traits<_ForwardIterator>::value_type>)
  88       __glibcxx_requires_valid_range(__first, __last);
  89
  90       for (; __first != __last; ++__first)
  91         {
  92           *__first = __value;
  93           ++__value;
  94         }
  95     }
  96
  97 _GLIBCXX_END_NAMESPACE
  98
  99 #endif
 100
 101 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_P)
 102
 103   /**
 104    *  @brief  Accumulate values in a range.
 105    *
 106    *  Accumulates the values in the range [first,last) using operator+().  The
 107    *  initial value is @a init.  The values are processed in order.
 108    *
 109    *  @param  first  Start of range.
 110    *  @param  last  End of range.
 111    *  @param  init  Starting value to add other values to.
 112    *  @return  The final sum.
 113    */
 114   template<typename _InputIterator, typename _Tp>
 115     inline _Tp
 116     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
 117     {
 118       // concept requirements
 119       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 120       __glibcxx_requires_valid_range(__first, __last);
 121
 122       for (; __first != __last; ++__first)
 123         __init = __init + *__first;
 124       return __init;
 125     }
 126
 127   /**
 128    *  @brief  Accumulate values in a range with operation.
 129    *
 130    *  Accumulates the values in the range [first,last) using the function
 131    *  object @a binary_op.  The initial value is @a init.  The values are
 132    *  processed in order.
 133    *
 134    *  @param  first  Start of range.
 135    *  @param  last  End of range.
 136    *  @param  init  Starting value to add other values to.
 137    *  @param  binary_op  Function object to accumulate with.
 138    *  @return  The final sum.
 139    */
 140   template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
 141     inline _Tp
 142     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
 143                _BinaryOperation __binary_op)
 144     {
 145       // concept requirements
 146       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 147       __glibcxx_requires_valid_range(__first, __last);
 148
 149       for (; __first != __last; ++__first)
 150         __init = __binary_op(__init, *__first);
 151       return __init;
 152     }
 153
 154   /**
 155    *  @brief  Compute inner product of two ranges.
 156    *
 157    *  Starting with an initial value of @a init, multiplies successive
 158    *  elements from the two ranges and adds each product into the accumulated
 159    *  value using operator+().  The values in the ranges are processed in
 160    *  order.
 161    *
 162    *  @param  first1  Start of range 1.
 163    *  @param  last1  End of range 1.
 164    *  @param  first2  Start of range 2.
 165    *  @param  init  Starting value to add other values to.
 166    *  @return  The final inner product.
 167    */
 168   template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
 169     inline _Tp
 170     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 171                   _InputIterator2 __first2, _Tp __init)
 172     {
 173       // concept requirements
 174       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
 175       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
 176       __glibcxx_requires_valid_range(__first1, __last1);
 177
 178       for (; __first1 != __last1; ++__first1, ++__first2)
 179         __init = __init + (*__first1 * *__first2);
 180       return __init;
 181     }
 182
 183   /**
 184    *  @brief  Compute inner product of two ranges.
 185    *
 186    *  Starting with an initial value of @a init, applies @a binary_op2 to
 187    *  successive elements from the two ranges and accumulates each result into
 188    *  the accumulated value using @a binary_op1.  The values in the ranges are
 189    *  processed in order.
 190    *
 191    *  @param  first1  Start of range 1.
 192    *  @param  last1  End of range 1.
 193    *  @param  first2  Start of range 2.
 194    *  @param  init  Starting value to add other values to.
 195    *  @param  binary_op1  Function object to accumulate with.
 196    *  @param  binary_op2  Function object to apply to pairs of input values.
 197    *  @return  The final inner product.
 198    */
 199   template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
 200            typename _BinaryOperation1, typename _BinaryOperation2>
 201     inline _Tp
 202     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 203                   _InputIterator2 __first2, _Tp __init,
 204                   _BinaryOperation1 __binary_op1,
 205                   _BinaryOperation2 __binary_op2)
 206     {
 207       // concept requirements
 208       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
 209       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
 210       __glibcxx_requires_valid_range(__first1, __last1);
 211
 212       for (; __first1 != __last1; ++__first1, ++__first2)
 213         __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
 214       return __init;
 215     }
 216
 217   /**
 218    *  @brief  Return list of partial sums
 219    *
 220    *  Accumulates the values in the range [first,last) using operator+().
 221    *  As each successive input value is added into the total, that partial sum
 222    *  is written to @a result.  Therefore, the first value in result is the
 223    *  first value of the input, the second value in result is the sum of the
 224    *  first and second input values, and so on.
 225    *
 226    *  @param  first  Start of input range.
 227    *  @param  last  End of input range.
 228    *  @param  result  Output to write sums to.
 229    *  @return  Iterator pointing just beyond the values written to result.
 230    */
 231   template<typename _InputIterator, typename _OutputIterator>
 232     _OutputIterator
 233     partial_sum(_InputIterator __first, _InputIterator __last,
 234                 _OutputIterator __result)
 235     {
 236       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 237
 238       // concept requirements
 239       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 240       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 241                                                          _ValueType>)
 242       __glibcxx_requires_valid_range(__first, __last);
 243
 244       if (__first == __last)
 245         return __result;
 246       _ValueType __value = *__first;
 247       *__result = __value;
 248       while (++__first != __last)
 249         {
 250           __value = __value + *__first;
 251           *++__result = __value;
 252         }
 253       return ++__result;
 254     }
 255
 256   /**
 257    *  @brief  Return list of partial sums
 258    *
 259    *  Accumulates the values in the range [first,last) using operator+().
 260    *  As each successive input value is added into the total, that partial sum
 261    *  is written to @a result.  Therefore, the first value in result is the
 262    *  first value of the input, the second value in result is the sum of the
 263    *  first and second input values, and so on.
 264    *
 265    *  @param  first  Start of input range.
 266    *  @param  last  End of input range.
 267    *  @param  result  Output to write sums to.
 268    *  @return  Iterator pointing just beyond the values written to result.
 269    */
 270   template<typename _InputIterator, typename _OutputIterator,
 271            typename _BinaryOperation>
 272     _OutputIterator
 273     partial_sum(_InputIterator __first, _InputIterator __last,
 274                 _OutputIterator __result, _BinaryOperation __binary_op)
 275     {
 276       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 277
 278       // concept requirements
 279       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 280       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 281                                                          _ValueType>)
 282       __glibcxx_requires_valid_range(__first, __last);
 283
 284       if (__first == __last)
 285         return __result;
 286       _ValueType __value = *__first;
 287       *__result = __value;
 288       while (++__first != __last)
 289         {
 290           __value = __binary_op(__value, *__first);
 291           *++__result = __value;
 292         }
 293       return ++__result;
 294     }
 295
 296   /**
 297    *  @brief  Return differences between adjacent values.
 298    *
 299    *  Computes the difference between adjacent values in the range
 300    *  [first,last) using operator-() and writes the result to @a result.
 301    *
 302    *  @param  first  Start of input range.
 303    *  @param  last  End of input range.
 304    *  @param  result  Output to write sums to.
 305    *  @return  Iterator pointing just beyond the values written to result.
 306    *
 307    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
 308    *  DR 539. partial_sum and adjacent_difference should mention requirements
 309    */
 310   template<typename _InputIterator, typename _OutputIterator>
 311     _OutputIterator
 312     adjacent_difference(_InputIterator __first,
 313                         _InputIterator __last, _OutputIterator __result)
 314     {
 315       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 316
 317       // concept requirements
 318       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 319       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 320                                                          _ValueType>)
 321       __glibcxx_requires_valid_range(__first, __last);
 322
 323       if (__first == __last)
 324         return __result;
 325       _ValueType __value = *__first;
 326       *__result = __value;
 327       while (++__first != __last)
 328         {
 329           _ValueType __tmp = *__first;
 330           *++__result = __tmp - __value;
 331           __value = _GLIBCXX_MOVE(__tmp);
 332         }
 333       return ++__result;
 334     }
 335
 336   /**
 337    *  @brief  Return differences between adjacent values.
 338    *
 339    *  Computes the difference between adjacent values in the range
 340    *  [first,last) using the function object @a binary_op and writes the
 341    *  result to @a result.
 342    *
 343    *  @param  first  Start of input range.
 344    *  @param  last  End of input range.
 345    *  @param  result  Output to write sums to.
 346    *  @return  Iterator pointing just beyond the values written to result.
 347    *
 348    *  _GLIBCXX_RESOLVE_LIB_DEFECTS
 349    *  DR 539. partial_sum and adjacent_difference should mention requirements
 350    */
 351   template<typename _InputIterator, typename _OutputIterator,
 352            typename _BinaryOperation>
 353     _OutputIterator
 354     adjacent_difference(_InputIterator __first, _InputIterator __last,
 355                         _OutputIterator __result, _BinaryOperation __binary_op)
 356     {
 357       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 358
 359       // concept requirements
 360       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 361       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 362                                                          _ValueType>)
 363       __glibcxx_requires_valid_range(__first, __last);
 364
 365       if (__first == __last)
 366         return __result;
 367       _ValueType __value = *__first;
 368       *__result = __value;
 369       while (++__first != __last)
 370         {
 371           _ValueType __tmp = *__first;
 372           *++__result = __binary_op(__tmp, __value);
 373           __value = _GLIBCXX_MOVE(__tmp);
 374         }
 375       return ++__result;
 376     }
 377
 378 _GLIBCXX_END_NESTED_NAMESPACE
 379
 380 #endif /* _STL_NUMERIC_H */