epan/fifo_string_cache.h

   1 /* fifo_string_cache.h
   2  * A string cache, possibly with a bounded size, using FIFO order to control
   3  * the size.
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11 #ifndef __FIFO_STRING_CACHE_H__
  12 #define __FIFO_STRING_CACHE_H__
  13
  14 #include <stdbool.h>
  15
  16 #include <glib.h>
  17
  18 #include "ws_symbol_export.h"
  19
  20 #ifdef __cplusplus
  21 extern "C" {
  22 #endif /* __cplusplus */
  23
  24 typedef struct {
  25     GHashTable          *set;
  26     GSList              *head;
  27     GSList              *tail;
  28     unsigned            max_entries;
  29 } fifo_string_cache_t;
  30
  31 // These functions are marked with WS_DLL_PUBLIC so they can be unit-tested
  32
  33 // Initialize an object. If string_free_func is given, then the
  34 // fifo_string_cache owns the string data, and will call this string_free_func
  35 // during fifo_string_cache_free().
  36 // If string_free_func is NULL, then the caller owns the string data, and it is
  37 // the caller that is responsible for freeing the data.
  38 WS_DLL_PUBLIC void
  39 fifo_string_cache_init(fifo_string_cache_t *fcache, unsigned max_entries, GDestroyNotify string_free_func);
  40
  41 // Free all memory owned by the fifo_string_cache. Whether or not the
  42 // fifoe_string_cache owns the actual strings depends on whether a
  43 // string_free_func was passed in during fifo_string_cache_init().
  44 WS_DLL_PUBLIC void
  45 fifo_string_cache_free(fifo_string_cache_t *fcache);
  46
  47 // Does the cache contain a specific string?
  48 WS_DLL_PUBLIC bool
  49 fifo_string_cache_contains(fifo_string_cache_t *fcache, const char *entry);
  50
  51 // Insert a string. The return value indicates whether the string was already
  52 // in the cache before this function was called. If the string was newly
  53 // inserted, and max_entries is > 0, and inserting the string would have caused
  54 // max_entries to be exceeded, the oldest inserted key is removed (FIFO order).
  55 WS_DLL_PUBLIC bool
  56 fifo_string_cache_insert(fifo_string_cache_t *fcache, const char *entry);
  57
  58 #ifdef __cplusplus
  59 }
  60 #endif /* __cplusplus */
  61
  62 #endif /* __FIFO_STRING_CACHE_H__ */