src/util/string_to_uint_map.h

   1 /*
   2  * Copyright © 2008 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24
  25 #ifndef STRING_TO_UINT_MAP_H
  26 #define STRING_TO_UINT_MAP_H
  27
  28 #include <string.h>
  29 #include <limits.h>
  30 #include "util/hash_table.h"
  31
  32 struct string_to_uint_map;
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 struct string_to_uint_map *
  39 string_to_uint_map_ctor();
  40
  41 void
  42 string_to_uint_map_dtor(struct string_to_uint_map *);
  43
  44
  45 #ifdef __cplusplus
  46 }
  47
  48 struct string_map_iterate_wrapper_closure {
  49    void (*callback)(const char *key, unsigned value, void *closure);
  50    void *closure;
  51 };
  52
  53 /**
  54  * Map from a string (name) to an unsigned integer value
  55  *
  56  * \note
  57  * Because of the way this class interacts with the \c hash_table
  58  * implementation, values of \c UINT_MAX cannot be stored in the map.
  59  */
  60 struct string_to_uint_map {
  61 public:
  62    string_to_uint_map()
  63    {
  64       this->ht = _mesa_hash_table_create(NULL, _mesa_key_hash_string,
  65                                          _mesa_key_string_equal);
  66    }
  67
  68    ~string_to_uint_map()
  69    {
  70       hash_table_call_foreach(this->ht, delete_key, NULL);
  71       _mesa_hash_table_destroy(this->ht, NULL);
  72    }
  73
  74    /**
  75     * Remove all mappings from this map.
  76     */
  77    void clear()
  78    {
  79       hash_table_call_foreach(this->ht, delete_key, NULL);
  80       _mesa_hash_table_clear(this->ht, NULL);
  81    }
  82
  83    /**
  84     * Runs a passed callback for the hash
  85     */
  86    void iterate(void (*func)(const char *, unsigned, void *), void *closure)
  87    {
  88       struct string_map_iterate_wrapper_closure *wrapper;
  89
  90       wrapper = (struct string_map_iterate_wrapper_closure *)
  91          malloc(sizeof(struct string_map_iterate_wrapper_closure));
  92       if (wrapper == NULL)
  93          return;
  94
  95       wrapper->callback = func;
  96       wrapper->closure = closure;
  97
  98       hash_table_call_foreach(this->ht, subtract_one_wrapper, wrapper);
  99       free(wrapper);
 100    }
 101
 102    /**
 103     * Get the value associated with a particular key
 104     *
 105     * \return
 106     * If \c key is found in the map, \c true is returned.  Otherwise \c false
 107     * is returned.
 108     *
 109     * \note
 110     * If \c key is not found in the table, \c value is not modified.
 111     */
 112    bool get(unsigned &value, const char *key)
 113    {
 114       hash_entry *entry = _mesa_hash_table_search(this->ht,
 115                                                   (const void *) key);
 116
 117       if (!entry)
 118          return false;
 119
 120       const intptr_t v = (intptr_t) entry->data;
 121       value = (unsigned)(v - 1);
 122       return true;
 123    }
 124
 125    void put(unsigned value, const char *key)
 126    {
 127       /* The low-level hash table structure returns NULL if key is not in the
 128        * hash table.  However, users of this map might want to store zero as a
 129        * valid value in the table.  Bias the value by +1 so that a
 130        * user-specified zero is stored as 1.  This enables ::get to tell the
 131        * difference between a user-specified zero (returned as 1 by
 132        * _mesa_hash_table_search) and the key not in the table (returned as 0 by
 133        * _mesa_hash_table_search).
 134        *
 135        * The net effect is that we can't store UINT_MAX in the table.  This is
 136        * because UINT_MAX+1 = 0.
 137        */
 138       assert(value != UINT_MAX);
 139       char *dup_key = strdup(key);
 140
 141       struct hash_entry *entry = _mesa_hash_table_search(this->ht, dup_key);
 142       if (entry) {
 143          entry->data = (void *) (intptr_t) (value + 1);
 144       } else {
 145          _mesa_hash_table_insert(this->ht, dup_key,
 146                                  (void *) (intptr_t) (value + 1));
 147       }
 148
 149       if (entry)
 150          free(dup_key);
 151    }
 152
 153 private:
 154    static void delete_key(const void *key, void *data, void *closure)
 155    {
 156       (void) data;
 157       (void) closure;
 158
 159       free((char *)key);
 160    }
 161
 162    static void subtract_one_wrapper(const void *key, void *data, void *closure)
 163    {
 164       struct string_map_iterate_wrapper_closure *wrapper =
 165          (struct string_map_iterate_wrapper_closure *) closure;
 166       unsigned value = (intptr_t) data;
 167
 168       value -= 1;
 169
 170       wrapper->callback((const char *) key, value, wrapper->closure);
 171    }
 172
 173    struct hash_table *ht;
 174 };
 175
 176 #endif /* __cplusplus */
 177 #endif /* STRING_TO_UINT_MAP_H */