mono/utils/mono-value-hash.h

   1 /**
   2  * \file
   3  * A hash table which only stores values in the hash nodes.
   4  *
   5  * Author:
   6  *   Mark Probst (mark.probst@gmail.com)
   7  *   Zoltan Varga (vargaz@gmail.com)
   8  *
   9  * (C) 2008 Novell, Inc.
  10  *
  11  */
  12 #ifndef __MONO_UTILS_MONO_VALUE_HASH__
  13 #define __MONO_UTILS_MONO_VALUE_HASH__
  14
  15 #include <glib.h>
  16 #include "mono-compiler.h"
  17
  18 /*
  19  * This is a hash table with the following features/restrictions:
  20  * - Keys are not stored in the table, instead a function must be supplied which
  21  *   computes them from the value.
  22  * - Values are assumed to be normal pointers, i.e. their lowest 2-3 bits should be
  23  *   zero.
  24  * - NULL values are not allowed.
  25  * - It uses internal probing instead of chaining.
  26  * - The above restrictions mean that this hash table will be somewhat slower than
  27  *   hash tables which store the key (or even the key hash) in the hash nodes. But
  28  *   it also means that each hash node has a size of one machine word, instead of
  29  * 4 in GHashTable.
  30  * - Removal of entries is not supported, as it is not needed by the runtime right
  31  *   now.
  32  */
  33
  34 typedef struct _MonoValueHashTable MonoValueHashTable;
  35
  36 typedef gpointer (*MonoValueHashKeyExtractFunc) (gpointer value);
  37
  38 MonoValueHashTable* mono_value_hash_table_new (GHashFunc hash_func,
  39                                                                                            GEqualFunc key_equal_func,
  40                                                                                            MonoValueHashKeyExtractFunc key_extract);
  41
  42 void
  43 mono_value_hash_table_destroy (MonoValueHashTable *table);
  44
  45 gpointer
  46 mono_value_hash_table_lookup (MonoValueHashTable *table, gconstpointer key);
  47
  48 /* The key pointer is actually only passed here to check a debugging
  49    assertion and to make the API look more familiar. */
  50 void
  51 mono_value_hash_table_insert (MonoValueHashTable *table,
  52                                  gpointer key, gpointer value);
  53
  54 #endif