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

   1 // Numeric functions implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2004, 2005 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996,1997
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 /** @file stl_numeric.h
  57  *  This is an internal header file, included by other library headers.
  58  *  You should not attempt to use it directly.
  59  */
  60
  61 #ifndef _STL_NUMERIC_H
  62 #define _STL_NUMERIC_H 1
  63
  64 #include <debug/debug.h>
  65
  66 _GLIBCXX_BEGIN_NAMESPACE(std)
  67
  68   /**
  69    *  @brief  Accumulate values in a range.
  70    *
  71    *  Accumulates the values in the range [first,last) using operator+().  The
  72    *  initial value is @a init.  The values are processed in order.
  73    *
  74    *  @param  first  Start of range.
  75    *  @param  last  End of range.
  76    *  @param  init  Starting value to add other values to.
  77    *  @return  The final sum.
  78    */
  79   template<typename _InputIterator, typename _Tp>
  80     _Tp
  81     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
  82     {
  83       // concept requirements
  84       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
  85       __glibcxx_requires_valid_range(__first, __last);
  86
  87       for (; __first != __last; ++__first)
  88         __init = __init + *__first;
  89       return __init;
  90     }
  91
  92   /**
  93    *  @brief  Accumulate values in a range with operation.
  94    *
  95    *  Accumulates the values in the range [first,last) using the function
  96    *  object @a binary_op.  The initial value is @a init.  The values are
  97    *  processed in order.
  98    *
  99    *  @param  first  Start of range.
 100    *  @param  last  End of range.
 101    *  @param  init  Starting value to add other values to.
 102    *  @param  binary_op  Function object to accumulate with.
 103    *  @return  The final sum.
 104    */
 105   template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
 106     _Tp
 107     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
 108                _BinaryOperation __binary_op)
 109     {
 110       // concept requirements
 111       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 112       __glibcxx_requires_valid_range(__first, __last);
 113
 114       for (; __first != __last; ++__first)
 115         __init = __binary_op(__init, *__first);
 116       return __init;
 117     }
 118
 119   /**
 120    *  @brief  Compute inner product of two ranges.
 121    *
 122    *  Starting with an initial value of @a init, multiplies successive
 123    *  elements from the two ranges and adds each product into the accumulated
 124    *  value using operator+().  The values in the ranges are processed in
 125    *  order.
 126    *
 127    *  @param  first1  Start of range 1.
 128    *  @param  last1  End of range 1.
 129    *  @param  first2  Start of range 2.
 130    *  @param  init  Starting value to add other values to.
 131    *  @return  The final inner product.
 132    */
 133   template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
 134     _Tp
 135     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 136                   _InputIterator2 __first2, _Tp __init)
 137     {
 138       // concept requirements
 139       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
 140       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
 141       __glibcxx_requires_valid_range(__first1, __last1);
 142
 143       for (; __first1 != __last1; ++__first1, ++__first2)
 144         __init = __init + (*__first1 * *__first2);
 145       return __init;
 146     }
 147
 148   /**
 149    *  @brief  Compute inner product of two ranges.
 150    *
 151    *  Starting with an initial value of @a init, applies @a binary_op2 to
 152    *  successive elements from the two ranges and accumulates each result into
 153    *  the accumulated value using @a binary_op1.  The values in the ranges are
 154    *  processed in order.
 155    *
 156    *  @param  first1  Start of range 1.
 157    *  @param  last1  End of range 1.
 158    *  @param  first2  Start of range 2.
 159    *  @param  init  Starting value to add other values to.
 160    *  @param  binary_op1  Function object to accumulate with.
 161    *  @param  binary_op2  Function object to apply to pairs of input values.
 162    *  @return  The final inner product.
 163    */
 164   template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
 165             typename _BinaryOperation1, typename _BinaryOperation2>
 166     _Tp
 167     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 168                   _InputIterator2 __first2, _Tp __init,
 169                   _BinaryOperation1 __binary_op1,
 170                   _BinaryOperation2 __binary_op2)
 171     {
 172       // concept requirements
 173       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
 174       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
 175       __glibcxx_requires_valid_range(__first1, __last1);
 176
 177       for (; __first1 != __last1; ++__first1, ++__first2)
 178         __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
 179       return __init;
 180     }
 181
 182   /**
 183    *  @brief  Return list of partial sums
 184    *
 185    *  Accumulates the values in the range [first,last) using operator+().
 186    *  As each successive input value is added into the total, that partial sum
 187    *  is written to @a result.  Therefore, the first value in result is the
 188    *  first value of the input, the second value in result is the sum of the
 189    *  first and second input values, and so on.
 190    *
 191    *  @param  first  Start of input range.
 192    *  @param  last  End of input range.
 193    *  @param  result  Output to write sums to.
 194    *  @return  Iterator pointing just beyond the values written to result.
 195    */
 196   template<typename _InputIterator, typename _OutputIterator>
 197     _OutputIterator
 198     partial_sum(_InputIterator __first, _InputIterator __last,
 199                 _OutputIterator __result)
 200     {
 201       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 202
 203       // concept requirements
 204       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 205       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 206                                                          _ValueType>)
 207       __glibcxx_requires_valid_range(__first, __last);
 208
 209       if (__first == __last)
 210         return __result;
 211       _ValueType __value = *__first;
 212       *__result = __value;
 213       while (++__first != __last)
 214         {
 215           __value = __value + *__first;
 216           *++__result = __value;
 217         }
 218       return ++__result;
 219     }
 220
 221   /**
 222    *  @brief  Return list of partial sums
 223    *
 224    *  Accumulates the values in the range [first,last) using operator+().
 225    *  As each successive input value is added into the total, that partial sum
 226    *  is written to @a result.  Therefore, the first value in result is the
 227    *  first value of the input, the second value in result is the sum of the
 228    *  first and second input values, and so on.
 229    *
 230    *  @param  first  Start of input range.
 231    *  @param  last  End of input range.
 232    *  @param  result  Output to write sums to.
 233    *  @return  Iterator pointing just beyond the values written to result.
 234    */
 235   template<typename _InputIterator, typename _OutputIterator,
 236            typename _BinaryOperation>
 237     _OutputIterator
 238     partial_sum(_InputIterator __first, _InputIterator __last,
 239                 _OutputIterator __result, _BinaryOperation __binary_op)
 240     {
 241       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 242
 243       // concept requirements
 244       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 245       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 246                                                          _ValueType>)
 247       __glibcxx_requires_valid_range(__first, __last);
 248
 249       if (__first == __last)
 250         return __result;
 251       _ValueType __value = *__first;
 252       *__result = __value;
 253       while (++__first != __last)
 254         {
 255           __value = __binary_op(__value, *__first);
 256           *++__result = __value;
 257         }
 258       return ++__result;
 259     }
 260
 261   /**
 262    *  @brief  Return differences between adjacent values.
 263    *
 264    *  Computes the difference between adjacent values in the range
 265    *  [first,last) using operator-() and writes the result to @a result.
 266    *
 267    *  @param  first  Start of input range.
 268    *  @param  last  End of input range.
 269    *  @param  result  Output to write sums to.
 270    *  @return  Iterator pointing just beyond the values written to result.
 271    */
 272   template<typename _InputIterator, typename _OutputIterator>
 273     _OutputIterator
 274     adjacent_difference(_InputIterator __first,
 275                         _InputIterator __last, _OutputIterator __result)
 276     {
 277       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 278
 279       // concept requirements
 280       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 281       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 282                                                          _ValueType>)
 283       __glibcxx_requires_valid_range(__first, __last);
 284
 285       if (__first == __last)
 286         return __result;
 287       _ValueType __value = *__first;
 288       *__result = __value;
 289       while (++__first != __last)
 290         {
 291           _ValueType __tmp = *__first;
 292           *++__result = __tmp - __value;
 293           __value = __tmp;
 294         }
 295       return ++__result;
 296     }
 297
 298   /**
 299    *  @brief  Return differences between adjacent values.
 300    *
 301    *  Computes the difference between adjacent values in the range
 302    *  [first,last) using the function object @a binary_op and writes the
 303    *  result to @a result.
 304    *
 305    *  @param  first  Start of input range.
 306    *  @param  last  End of input range.
 307    *  @param  result  Output to write sums to.
 308    *  @return  Iterator pointing just beyond the values written to result.
 309    */
 310   template<typename _InputIterator, typename _OutputIterator,
 311            typename _BinaryOperation>
 312     _OutputIterator
 313     adjacent_difference(_InputIterator __first, _InputIterator __last,
 314                         _OutputIterator __result, _BinaryOperation __binary_op)
 315     {
 316       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 317
 318       // concept requirements
 319       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 320       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
 321                                                          _ValueType>)
 322       __glibcxx_requires_valid_range(__first, __last);
 323
 324       if (__first == __last)
 325         return __result;
 326       _ValueType __value = *__first;
 327       *__result = __value;
 328       while (++__first != __last)
 329         {
 330           _ValueType __tmp = *__first;
 331           *++__result = __binary_op(__tmp, __value);
 332           __value = __tmp;
 333         }
 334       return ++__result;
 335     }
 336
 337 _GLIBCXX_END_NAMESPACE
 338
 339 #endif /* _STL_NUMERIC_H */