glib/gbsearcharray.h

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 2000-2001 Tim Janik
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  *
  19  * gbsearcharray.h: binary searchable sorted array maintenance
  20  */
  21 #ifndef __G_BSEARCH_ARRAY_H__
  22 #define __G_BSEARCH_ARRAY_H__
  23
  24 #include        <glib/gtypes.h>
  25 #include        <glib/gutils.h>
  26 #include        <glib/gmem.h>
  27 #include        <glib/gmessages.h>
  28
  29 G_BEGIN_DECLS
  30
  31 /* helper macro to avoid signed overflow for value comparisions */
  32 #define G_BSEARCH_ARRAY_CMP(v1,v2) ((v1) < (v2) ? -1 : (v1) > (v2))
  33
  34
  35 /* --- typedefs --- */
  36 typedef union  _GBSearchArray         GBSearchArray;
  37 typedef struct _GBSearchConfig        GBSearchConfig;
  38 typedef gint  (*GBSearchCompareFunc) (gconstpointer bsearch_node1,
  39                                       gconstpointer bsearch_node2);
  40 typedef enum
  41 {
  42   G_BSEARCH_ARRAY_ALIGN_POWER2  = 1 << 0,
  43   G_BSEARCH_ARRAY_DEFER_SHRINK  = 1 << 1
  44 } GBSearchArrayFlags;
  45
  46
  47 /* --- structures --- */
  48 struct _GBSearchConfig
  49 {
  50   guint16             sizeof_node;
  51   GBSearchCompareFunc cmp_nodes;
  52   guint16             flags;
  53 };
  54 union _GBSearchArray
  55 {
  56   guint    n_nodes;
  57   gpointer alignment_dummy1;
  58   glong    alignment_dummy2;
  59   gdouble  alignment_dummy3;
  60 };
  61
  62
  63 /* --- prototypes --- */
  64 GBSearchArray*  g_bsearch_array_new             (GBSearchConfig *bconfig);
  65 void            g_bsearch_array_destroy         (GBSearchArray  *barray,
  66                                                  GBSearchConfig *bconfig);
  67 GBSearchArray*  g_bsearch_array_insert          (GBSearchArray  *barray,
  68                                                  GBSearchConfig *bconfig,
  69                                                  gconstpointer   key_node,
  70                                                  gboolean        replace_existing);
  71 GBSearchArray*  g_bsearch_array_remove          (GBSearchArray  *barray,
  72                                                  GBSearchConfig *bconfig,
  73                                                  gconstpointer   key_node);
  74 GBSearchArray*  g_bsearch_array_remove_node     (GBSearchArray  *barray,
  75                                                  GBSearchConfig *bconfig,
  76                                                  gpointer        node_in_array);
  77 G_INLINE_FUNC
  78 gpointer        g_bsearch_array_lookup          (GBSearchArray  *barray,
  79                                                  GBSearchConfig *bconfig,
  80                                                  gconstpointer   key_node);
  81 G_INLINE_FUNC
  82 gpointer        g_bsearch_array_get_nth         (GBSearchArray  *barray,
  83                                                  GBSearchConfig *bconfig,
  84                                                  guint           n);
  85 G_INLINE_FUNC
  86 guint           g_bsearch_array_get_index       (GBSearchArray  *barray,
  87                                                  GBSearchConfig *bconfig,
  88                                                  gpointer        node_in_array);
  89
  90
  91 /* initialization of static arrays */
  92 #define G_STATIC_BCONFIG(sizeof_node, cmp_nodes, flags) \
  93   { (sizeof_node), (cmp_nodes), (flags), }
  94
  95
  96 /* --- implementation details --- */
  97 #define G_BSEARCH_ARRAY_NODES(barray)    ((gpointer) (((guint8*) (barray)) + sizeof (GBSearchArray)))
  98 #if defined (G_CAN_INLINE) || defined (__G_BSEARCHARRAY_C__)
  99 G_INLINE_FUNC gpointer
 100 g_bsearch_array_lookup (GBSearchArray  *barray,
 101                         GBSearchConfig *bconfig,
 102                         gconstpointer   key_node)
 103 {
 104   if (barray->n_nodes > 0)
 105     {
 106       GBSearchCompareFunc cmp_nodes = bconfig->cmp_nodes;
 107       gint sizeof_node = bconfig->sizeof_node;
 108       guint n_nodes = barray->n_nodes;
 109       guint8 *nodes = G_BSEARCH_ARRAY_NODES (barray);
 110
 111       nodes -= sizeof_node;
 112       do
 113         {
 114           guint8 *check;
 115           guint i;
 116           register gint cmp;
 117
 118           i = (n_nodes + 1) >> 1;
 119           check = nodes + i * sizeof_node;
 120           cmp = cmp_nodes (key_node, check);
 121           if (cmp == 0)
 122             return check;
 123           else if (cmp > 0)
 124             {
 125               n_nodes -= i;
 126               nodes = check;
 127             }
 128           else /* if (cmp < 0) */
 129             n_nodes = i - 1;
 130         }
 131       while (n_nodes);
 132     }
 133
 134   return NULL;
 135 }
 136 G_INLINE_FUNC gpointer
 137 g_bsearch_array_get_nth (GBSearchArray  *barray,
 138                          GBSearchConfig *bconfig,
 139                          guint           n)
 140 {
 141   if (n < barray->n_nodes)
 142     {
 143       guint8 *nodes = (guint8*) G_BSEARCH_ARRAY_NODES (barray);
 144
 145       return nodes + n * bconfig->sizeof_node;
 146     }
 147   else
 148     return NULL;
 149 }
 150 G_INLINE_FUNC
 151 guint
 152 g_bsearch_array_get_index (GBSearchArray  *barray,
 153                            GBSearchConfig *bconfig,
 154                            gpointer        node_in_array)
 155 {
 156   guint distance = ((guint8*) node_in_array) - ((guint8*) G_BSEARCH_ARRAY_NODES (barray));
 157
 158   distance /= bconfig->sizeof_node;
 159
 160   return MIN (distance, barray->n_nodes);
 161 }
 162 #endif  /* G_CAN_INLINE || __G_BSEARCHARRAY_C__ */
 163
 164 G_END_DECLS
 165
 166 #endif /* __G_BSEARCH_ARRAY_H__ */