lib/gl_set.hh

   1 /* Abstract set data type as a C++ class.
   2    Copyright (C) 2006-2020 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2018.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _GL_SET_HH
  19 #define _GL_SET_HH
  20
  21 #include "gl_set.h"
  22 #include "gl_xset.h"
  23
  24 /* gl_Set is a C++ wrapper around the gl_set data type.
  25    Its element type is 'ELTYPE *'.
  26
  27    It is merely a pointer, not a smart pointer. In other words:
  28    it does NOT do reference-counting, and the destructor does nothing.  */
  29
  30 template <class T> class gl_Set;
  31
  32 template <class ELTYPE>
  33 class gl_Set<ELTYPE *>
  34 {
  35 public:
  36   // ------------------------------ Constructors ------------------------------
  37
  38   gl_Set ()
  39     : _ptr (NULL)
  40     {}
  41
  42   /* Creates an empty set.
  43      IMPLEMENTATION is one of GL_ARRAY_SET, GL_LINKEDHASH_SET, GL_HASH_SET.
  44      EQUALS_FN is an element comparison function or NULL.
  45      HASHCODE_FN is an element hash code function or NULL.
  46      DISPOSE_FN is an element disposal function or NULL.  */
  47   gl_Set (gl_set_implementation_t implementation,
  48           bool (*equals_fn) (ELTYPE * /*elt1*/, ELTYPE * /*elt2*/),
  49           size_t (*hashcode_fn) (ELTYPE *),
  50           void (*dispose_fn) (ELTYPE *))
  51     : _ptr (gl_set_create_empty (implementation,
  52                                  reinterpret_cast<gl_setelement_equals_fn>(equals_fn),
  53                                  reinterpret_cast<gl_setelement_hashcode_fn>(hashcode_fn),
  54                                  reinterpret_cast<gl_setelement_dispose_fn>(dispose_fn)))
  55     {}
  56
  57   /* Copy constructor.  */
  58   gl_Set (const gl_Set& x)
  59     { _ptr = x._ptr; }
  60
  61   /* Assignment operator.  */
  62   gl_Set& operator= (const gl_Set& x)
  63     { _ptr = x._ptr; return *this; }
  64
  65   // ------------------------------- Destructor -------------------------------
  66
  67   ~gl_Set ()
  68     { _ptr = NULL; }
  69
  70   // ----------------------- Read-only member functions -----------------------
  71
  72   /* Returns the current number of elements in the set.  */
  73   size_t size () const
  74     { return gl_set_size (_ptr); }
  75
  76   /* Searches whether an element is already in the set.
  77      Returns true if found, or false if not present in the set.  */
  78   bool search (ELTYPE * elt) const
  79     { return gl_set_search (_ptr, elt); }
  80
  81   // ----------------------- Modifying member functions -----------------------
  82
  83   /* Adds an element to the set.
  84      Returns true if it was not already in the set and added, false otherwise.  */
  85   bool add (ELTYPE * elt)
  86     { return gl_set_add (_ptr, elt); }
  87
  88   /* Removes an element from the set.
  89      Returns true if it was found and removed.  */
  90   bool remove (ELTYPE * elt)
  91     { return gl_set_remove (_ptr, elt); }
  92
  93   /* Frees the entire set.
  94      (But this call does not free the elements of the set.  It only invokes
  95      the DISPOSE_FN on each of the elements of the set.)  */
  96   void free ()
  97     { gl_set_free (_ptr); _ptr = NULL; }
  98
  99   // ------------------------------ Private stuff ------------------------------
 100
 101 private:
 102   gl_set_t _ptr;
 103
 104 public:
 105   // -------------------------------- Iterators --------------------------------
 106   // Only a forward iterator.
 107   // Does not implement the STL operations (++, *, and != .end()), but a simpler
 108   // interface that needs only one virtual function call per iteration instead
 109   // of three.
 110
 111   class iterator {
 112   public:
 113
 114     /* If there is a next element, stores the next element in ELT, advances the
 115        iterator and returns true.  Otherwise, returns false.  */
 116     bool next (ELTYPE *& elt)
 117       {
 118         const void *next_elt;
 119         bool has_next = gl_set_iterator_next (&_state, &next_elt);
 120         if (has_next)
 121           elt = static_cast<ELTYPE *>(next_elt);
 122         return has_next;
 123       }
 124
 125     ~iterator ()
 126       { gl_set_iterator_free (&_state); }
 127
 128   #if defined __xlC__ || defined __HP_aCC || defined __SUNPRO_CC
 129   public:
 130   #else
 131   private:
 132     friend iterator gl_Set::begin ();
 133   #endif
 134
 135     iterator (gl_set_t ptr)
 136       : _state (gl_set_iterator (ptr))
 137       {}
 138
 139   private:
 140
 141     gl_set_iterator_t _state;
 142   };
 143
 144   /* Creates an iterator traversing the set.
 145      The set's contents must not be modified while the iterator is in use,
 146      except for removing the last returned element.  */
 147   iterator begin ()
 148     { return iterator (_ptr); }
 149 };
 150
 151 #endif /* _GL_SET_HH */