forked from enlightenment/efl
246 lines
7.3 KiB
C
246 lines
7.3 KiB
C
/*
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* vim:ts=8:sw=3:sts=8:noexpandtab:cino=>5n-3f0^-2{2
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*/
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/* EINA - EFL data type library
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* Copyright (C) 2002-2008 Carsten Haitzler, Jorge Luis Zapata Muga, Cedric Bail
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library;
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* if not, see <http://www.gnu.org/licenses/>.
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*
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* This file incorporates work covered by the following copyright and
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* permission notice:
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*
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* Copyright (C) 2008 Peter Wehrfritz
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies of the Software and its Copyright notices. In addition publicly
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* documented acknowledgment must be given that this software has been used if no
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* source code of this software is made available publicly. This includes
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* acknowledgments in either Copyright notices, Manuals, Publicity and Marketing
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* documents or any documentation provided with any product containing this
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* software. This License does not apply to any software that links to the
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* libraries provided by this software (statically or dynamically), but only to
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* the software provided.
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*
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* Please see the OLD-COPYING.PLAIN for a plain-english explanation of this notice
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* and it's intent.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "eina_stringshare.h"
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#include "eina_hash.h"
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#include "eina_error.h"
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#include "eina_private.h"
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typedef struct _Eina_Stringshare Eina_Stringshare;
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typedef struct _Eina_Stringshare_Node Eina_Stringshare_Node;
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struct _Eina_Stringshare
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{
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Eina_Stringshare_Node *buckets[1024];
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};
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struct _Eina_Stringshare_Node
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{
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Eina_Stringshare_Node *next;
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int references;
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};
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static Eina_Stringshare *share = NULL;
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static int eina_stringshare_init_count = 0;
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/**
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* @defgroup Eina_Stringshare_Group String Instance Functions
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*
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* These functions allow you to store one copy of a string, and use it
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* throughout your program.
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*
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* This is a method to reduce the number of duplicated strings kept in
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* memory. It's pretty common for the same strings to be dynamically
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* allocated repeatedly between applications and libraries, especially in
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* circumstances where you could have multiple copies of a structure that
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* allocates the string. So rather than duplicating and freeing these
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* strings, you request a read-only pointer to an existing string and
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* only incur the overhead of a hash lookup.
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*
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* It sounds like micro-optimizing, but profiling has shown this can have
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* a significant impact as you scale the number of copies up. It improves
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* string creation/destruction speed, reduces memory use and decreases
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* memory fragmentation, so a win all-around.
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*/
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/**
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* Initialize the eina stringshare internal structure.
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* @return Zero on failure, non-zero on successful initialization.
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*/
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EAPI int
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eina_stringshare_init()
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{
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/*
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* No strings have been loaded at this point, so create the hash
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* table for storing string info for later.
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*/
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if (!eina_stringshare_init_count)
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{
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share = calloc(1, sizeof(Eina_Stringshare));
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if (!share)
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return 0;
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eina_error_init();
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}
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eina_stringshare_init_count++;
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return 1;
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}
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/**
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* Retrieves an instance of a string for use in a program.
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* @param str The string to retrieve an instance of.
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* @return A pointer to an instance of the string on success.
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* @c NULL on failure.
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* @ingroup Eina_Stringshare_Group
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*/
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EAPI const char *
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eina_stringshare_add(const char *str)
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{
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int hash_num, slen;
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char *el_str;
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Eina_Stringshare_Node *el, *pel = NULL;
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if (!str) return NULL;
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slen = strlen(str) + 1;
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hash_num = eina_hash_superfast(str, slen) & 0x3FF;
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for (el = share->buckets[hash_num]; el; pel = el, el = el->next)
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{
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el_str = ((char *)el) + sizeof(Eina_Stringshare_Node);
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if (!strcmp(el_str, str))
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{
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if (pel)
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{
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pel->next = el->next;
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el->next = share->buckets[hash_num];
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share->buckets[hash_num] = el;
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}
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el->references++;
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return el_str;
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}
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}
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if (!(el = malloc(sizeof(Eina_Stringshare_Node) + slen + 1))) return NULL;
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el_str = ((char *)el) + sizeof(Eina_Stringshare_Node);
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strcpy(el_str, str);
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el->references = 1;
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el->next = share->buckets[hash_num];
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share->buckets[hash_num] = el;
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return el_str;
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}
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/**
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* Notes that the given string has lost an instance.
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*
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* It will free the string if no other instances are left.
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*
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* @param str string The given string.
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* @ingroup Eina_Stringshare_Group
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*/
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EAPI void
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eina_stringshare_del(const char *str)
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{
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int hash_num, slen;
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char *el_str;
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Eina_Stringshare_Node *el, *pel = NULL;
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if (!str) return;
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slen = strlen(str) + 1;
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hash_num = eina_hash_superfast(str, slen) & 0x3FF;
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for (el = share->buckets[hash_num]; el; pel = el, el = el->next)
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{
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el_str = ((char *)el) + sizeof(Eina_Stringshare_Node);
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if (el_str == str)
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{
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el->references--;
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if (el->references == 0)
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{
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if (pel) pel->next = el->next;
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else share->buckets[hash_num] = el->next;
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free(el);
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}
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else
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{
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if (pel)
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{
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pel->next = el->next;
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el->next = share->buckets[hash_num];
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share->buckets[hash_num] = el;
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}
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}
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return;
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}
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}
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EINA_ERROR_PWARN("EEEK trying to del non-shared stringshare \"%s\"\n", str);
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if (getenv("EINA_ERROR_ABORT")) abort();
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}
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/**
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* Shutdown the eina string internal structures
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*/
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EAPI int
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eina_stringshare_shutdown()
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{
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--eina_stringshare_init_count;
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if (!eina_stringshare_init_count)
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{
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int i;
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/* remove any string still in the table */
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for (i = 0; i < 1024; i++)
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{
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Eina_Stringshare_Node *el = share->buckets[i];
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while (el)
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{
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Eina_Stringshare_Node *cur = el;
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el = el->next;
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cur->next = NULL;
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free(cur);
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}
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share->buckets[i] = NULL;
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}
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free(share);
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share = NULL;
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eina_error_shutdown();
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}
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return eina_stringshare_init_count;
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}
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