include/AD/sort/shellsrt.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are free to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome any suggestions
  19 // and help from the users.
  20 //
  21 // Allen Leung
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef Shellsort_h
  26 #define Shellsort_h
  27
  28 #include <AD/sort/sorting.h>
  29 //
  30 //  Shell sort\cite{algo-hand-book}
  31 //
  32 //  e.g: shellSort(char *, names, 100, strcmp(key,names[i]) < 0);
  33 //
  34
  35 /////////////////////////////////////////////////////////////////////////////
  36 // Macro version
  37 /////////////////////////////////////////////////////////////////////////////
  38 #define shellSort(TYPE,A,N,predicate)                                         \
  39    do {                                                                       \
  40       for ( register int gap = (N); gap > 1; ) {                              \
  41          if (gap < 5) gap = 1;                                                \
  42          else gap = (5 * gap - 1) / 11;                                       \
  43          for (register int j = (N) - gap; j >= 0; j--) {                      \
  44             register TYPE key = (A)[j];                                       \
  45             for (register int i = j + gap; i < (N) && !(predicate); i += gap) \
  46                (A)[i-gap] = (A)[i];                                           \
  47             (A)[i-gap] = key;                                                 \
  48          }                                                                    \
  49       }                                                                       \
  50    } while(0)
  51
  52 /////////////////////////////////////////////////////////////////////////////
  53 // Template version
  54 /////////////////////////////////////////////////////////////////////////////
  55 template <class T, class Ord>
  56    class ShellSort : public Sorting<T,Ord> {
  57    public:
  58       void sort(int, T []);
  59    };
  60
  61 template <class T, class Ord>
  62    void ShellSort<T,Ord>::sort(int N, T array[])
  63    {  shellSort(T, array, N, Ord::less(key, array[i])); }
  64
  65 #endif