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

   1 // Numeric functions implementation -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2004 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  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 namespace std
  67 {
  68
  69   /**
  70    *  @brief  Accumulate values in a range.
  71    *
  72    *  Accumulates the values in the range [first,last) using operator+().  The
  73    *  initial value is @a init.  The values are processed in order.
  74    *
  75    *  @param  first  Start of range.
  76    *  @param  last  End of range.
  77    *  @param  init  Starting value to add other values to.
  78    *  @return  The final sum.
  79    */
  80   template<typename _InputIterator, typename _Tp>
  81     _Tp
  82     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
  83     {
  84       // concept requirements
  85       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
  86       __glibcxx_requires_valid_range(__first, __last);
  87
  88       for ( ; __first != __last; ++__first)
  89         __init = __init + *__first;
  90       return __init;
  91     }
  92
  93   /**
  94    *  @brief  Accumulate values in a range with operation.
  95    *
  96    *  Accumulates the values in the range [first,last) using the function
  97    *  object @a binary_op.  The initial value is @a init.  The values are
  98    *  processed in order.
  99    *
 100    *  @param  first  Start of range.
 101    *  @param  last  End of range.
 102    *  @param  init  Starting value to add other values to.
 103    *  @param  binary_op  Function object to accumulate with.
 104    *  @return  The final sum.
 105    */
 106   template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
 107     _Tp
 108     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
 109                _BinaryOperation __binary_op)
 110     {
 111       // concept requirements
 112       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 113       __glibcxx_requires_valid_range(__first, __last);
 114
 115       for ( ; __first != __last; ++__first)
 116         __init = __binary_op(__init, *__first);
 117       return __init;
 118     }
 119
 120   /**
 121    *  @brief  Compute inner product of two ranges.
 122    *
 123    *  Starting with an initial value of @a init, multiplies successive
 124    *  elements from the two ranges and adds each product into the accumulated
 125    *  value using operator+().  The values in the ranges are processed in
 126    *  order.
 127    *
 128    *  @param  first1  Start of range 1.
 129    *  @param  last1  End of range 1.
 130    *  @param  first2  Start of range 2.
 131    *  @param  init  Starting value to add other values to.
 132    *  @return  The final inner product.
 133    */
 134   template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
 135     _Tp
 136     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 137                   _InputIterator2 __first2, _Tp __init)
 138     {
 139       // concept requirements
 140       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
 141       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
 142       __glibcxx_requires_valid_range(__first1, __last1);
 143
 144       for ( ; __first1 != __last1; ++__first1, ++__first2)
 145         __init = __init + (*__first1 * *__first2);
 146       return __init;
 147     }
 148
 149   /**
 150    *  @brief  Compute inner product of two ranges.
 151    *
 152    *  Starting with an initial value of @a init, applies @a binary_op2 to
 153    *  successive elements from the two ranges and accumulates each result into
 154    *  the accumulated value using @a binary_op1.  The values in the ranges are
 155    *  processed in order.
 156    *
 157    *  @param  first1  Start of range 1.
 158    *  @param  last1  End of range 1.
 159    *  @param  first2  Start of range 2.
 160    *  @param  init  Starting value to add other values to.
 161    *  @param  binary_op1  Function object to accumulate with.
 162    *  @param  binary_op2  Function object to apply to pairs of input values.
 163    *  @return  The final inner product.
 164    */
 165   template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
 166             typename _BinaryOperation1, typename _BinaryOperation2>
 167     _Tp
 168     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 169                   _InputIterator2 __first2, _Tp __init,
 170                   _BinaryOperation1 __binary_op1,
 171                   _BinaryOperation2 __binary_op2)
 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 = __binary_op1(__init, __binary_op2(*__first1, *__first2));
 180       return __init;
 181     }
 182
 183   /**
 184    *  @brief  Return list of partial sums
 185    *
 186    *  Accumulates the values in the range [first,last) using operator+().
 187    *  As each successive input value is added into the total, that partial sum
 188    *  is written to @a result.  Therefore, the first value in result is the
 189    *  first value of the input, the second value in result is the sum of the
 190    *  first and second input values, and so on.
 191    *
 192    *  @param  first  Start of input range.
 193    *  @param  last  End of input range.
 194    *  @param  result  Output to write sums to.
 195    *  @return  Iterator pointing just beyond the values written to result.
 196    */
 197   template<typename _InputIterator, typename _OutputIterator>
 198     _OutputIterator
 199     partial_sum(_InputIterator __first, _InputIterator __last,
 200                 _OutputIterator __result)
 201     {
 202       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 203
 204       // concept requirements
 205       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 206       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)
 207       __glibcxx_requires_valid_range(__first, __last);
 208
 209       if (__first == __last) return __result;
 210       *__result = *__first;
 211       _ValueType __value = *__first;
 212       while (++__first != __last) {
 213         __value = __value + *__first;
 214         *++__result = __value;
 215       }
 216       return ++__result;
 217     }
 218
 219   /**
 220    *  @brief  Return list of partial sums
 221    *
 222    *  Accumulates the values in the range [first,last) using operator+().
 223    *  As each successive input value is added into the total, that partial sum
 224    *  is written to @a result.  Therefore, the first value in result is the
 225    *  first value of the input, the second value in result is the sum of the
 226    *  first and second input values, and so on.
 227    *
 228    *  @param  first  Start of input range.
 229    *  @param  last  End of input range.
 230    *  @param  result  Output to write sums to.
 231    *  @return  Iterator pointing just beyond the values written to result.
 232    */
 233   template<typename _InputIterator, typename _OutputIterator, typename _BinaryOperation>
 234     _OutputIterator
 235     partial_sum(_InputIterator __first, _InputIterator __last,
 236                 _OutputIterator __result, _BinaryOperation __binary_op)
 237     {
 238       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 239
 240       // concept requirements
 241       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 242       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)
 243       __glibcxx_requires_valid_range(__first, __last);
 244
 245       if (__first == __last) return __result;
 246       *__result = *__first;
 247       _ValueType __value = *__first;
 248       while (++__first != __last) {
 249         __value = __binary_op(__value, *__first);
 250         *++__result = __value;
 251       }
 252       return ++__result;
 253     }
 254
 255   /**
 256    *  @brief  Return differences between adjacent values.
 257    *
 258    *  Computes the difference between adjacent values in the range
 259    *  [first,last) using operator-() and writes the result to @a result.
 260    *
 261    *  @param  first  Start of input range.
 262    *  @param  last  End of input range.
 263    *  @param  result  Output to write sums to.
 264    *  @return  Iterator pointing just beyond the values written to result.
 265    */
 266   template<typename _InputIterator, typename _OutputIterator>
 267     _OutputIterator
 268     adjacent_difference(_InputIterator __first,
 269                         _InputIterator __last, _OutputIterator __result)
 270     {
 271       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 272
 273       // concept requirements
 274       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 275       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)
 276       __glibcxx_requires_valid_range(__first, __last);
 277
 278       if (__first == __last) return __result;
 279       *__result = *__first;
 280       _ValueType __value = *__first;
 281       while (++__first != __last) {
 282         _ValueType __tmp = *__first;
 283         *++__result = __tmp - __value;
 284         __value = __tmp;
 285       }
 286       return ++__result;
 287     }
 288
 289   /**
 290    *  @brief  Return differences between adjacent values.
 291    *
 292    *  Computes the difference between adjacent values in the range
 293    *  [first,last) using the function object @a binary_op and writes the
 294    *  result to @a result.
 295    *
 296    *  @param  first  Start of input range.
 297    *  @param  last  End of input range.
 298    *  @param  result  Output to write sums to.
 299    *  @return  Iterator pointing just beyond the values written to result.
 300    */
 301   template<typename _InputIterator, typename _OutputIterator, typename _BinaryOperation>
 302     _OutputIterator
 303     adjacent_difference(_InputIterator __first, _InputIterator __last,
 304                         _OutputIterator __result, _BinaryOperation __binary_op)
 305     {
 306       typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
 307
 308       // concept requirements
 309       __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
 310       __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)
 311       __glibcxx_requires_valid_range(__first, __last);
 312
 313       if (__first == __last) return __result;
 314       *__result = *__first;
 315       _ValueType __value = *__first;
 316       while (++__first != __last) {
 317         _ValueType __tmp = *__first;
 318         *++__result = __binary_op(__tmp, __value);
 319         __value = __tmp;
 320       }
 321       return ++__result;
 322     }
 323
 324 } // namespace std
 325
 326 #endif /* _STL_NUMERIC_H */