efl/src/include/eina/eina_ustringshare.h

202 lines
7.7 KiB
C

/* EINA - EFL data type library
* Copyright (C) 2002-2008 Carsten Haitzler, Jorge Luis Zapata Muga, Cedric Bail
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library;
* if not, see <http://www.gnu.org/licenses/>.
*
* This file incorporates work covered by the following copyright and
* permission notice:
*
* Copyright (C) 2008 Peter Wehrfritz
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies of the Software and its Copyright notices. In addition publicly
* documented acknowledgment must be given that this software has been used if no
* source code of this software is made available publicly. This includes
* acknowledgments in either Copyright notices, Manuals, Publicity and Marketing
* documents or any documentation provided with any product containing this
* software. This License does not apply to any software that links to the
* libraries provided by this software (statically or dynamically), but only to
* the software provided.
*
* Please see the OLD-COPYING.PLAIN for a plain-english explanation of this notice
* and it's intent.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef EINA_USTRINGSHARE_H_
#define EINA_USTRINGSHARE_H_
#include "eina_types.h"
#include "eina_unicode.h"
/**
* @addtogroup Eina_UStringshare_Group Unicode Stringshare
*
* These functions allow you to store one copy of a string, and use it
* throughout your program.
*
* This is a method to reduce the number of duplicated strings kept in
* memory. It's pretty common for the same strings to be dynamically
* allocated repeatedly between applications and libraries, especially in
* circumstances where you could have multiple copies of a structure that
* allocates the string. So rather than duplicating and freeing these
* strings, you request a read-only pointer to an existing string and
* only incur the overhead of a hash lookup.
*
* It sounds like micro-optimizing, but profiling has shown this can have
* a significant impact as you scale the number of copies up. It improves
* string creation/destruction speed, reduces memory use and decreases
* memory fragmentation, so a win all-around.
*
* For more information, you can look at the @ref tutorial_ustringshare_page.
*/
/**
* @addtogroup Eina_Data_Types_Group Data Types
*
* @{
*/
/**
* @defgroup Eina_UStringshare_Group Unicode Stringshare
*
* @{
*/
/**
* @brief Retrieve an instance of a string for use in a program.
*
* @param str The string to retrieve an instance of.
* @param slen The string size (<= strlen(str)).
* @return A pointer to an instance of the string on success.
* @c NULL on failure.
*
* This function retrieves an instance of @p str. If @p str is
* @c NULL, then @c NULL is returned. If @p str is already stored, it
* is just returned and its reference counter is increased. Otherwise
* it is added to the strings to be searched and a duplicated string
* of @p str is returned.
*
* This function does not check string size, but uses the
* exact given size. This can be used to share_common part of a larger
* buffer or substring.
*
* @see eina_ustringshare_add()
*/
EAPI const Eina_Unicode *eina_ustringshare_add_length(const Eina_Unicode *str, unsigned int slen) EINA_WARN_UNUSED_RESULT;
/**
* @brief Retrieve an instance of a string for use in a program.
*
* @param str The NULL-terminated string to retrieve an instance of.
* @return A pointer to an instance of the string on success.
* @c NULL on failure.
*
* This function retrieves an instance of @p str. If @p str is
* @c NULL, then @c NULL is returned. If @p str is already stored, it
* is just returned and its reference counter is increased. Otherwise
* it is added to the strings to be searched and a duplicated string
* of @p str is returned.
*
* The string @p str must be NULL-terminated ('@\0') and its full
* length will be used. To use part of the string or non-null
* terminated, use eina_stringshare_add_length() instead.
*
* @see eina_ustringshare_add_length()
*/
EAPI const Eina_Unicode *eina_ustringshare_add(const Eina_Unicode *str) EINA_WARN_UNUSED_RESULT;
/**
* Increment references of the given shared string.
*
* @param str The shared string.
* @return A pointer to an instance of the string on success.
* @c NULL on failure.
*
* This is similar to eina_share_common_add(), but it's faster since it will
* avoid lookups if possible, but on the down side it requires the parameter
* to be shared before, in other words, it must be the return of a previous
* eina_ustringshare_add().
*
* There is no unref since this is the work of eina_ustringshare_del().
*/
EAPI const Eina_Unicode *eina_ustringshare_ref(const Eina_Unicode *str);
/**
* @brief Note that the given string has lost an instance.
*
* @param str string The given string.
*
* This function decreases the reference counter associated to @p str
* if it exists. If that counter reaches 0, the memory associated to
* @p str is freed. If @p str is @c NULL, the function returns
* immediately.
*
* @note If the given pointer is not shared, bad things will happen, likely a
* segmentation fault.
*/
EAPI void eina_ustringshare_del(const Eina_Unicode *str);
/**
* @brief Note that the given string @b must be shared.
*
* @param str the shared string to know the length. It is safe to
* give @c NULL, in that case @c -1 is returned.
*
* This function is a cheap way to known the length of a shared
* string.
*
* @note If the given pointer is not shared, bad things will happen, likely a
* segmentation fault. If in doubt, try strlen().
*/
EAPI int eina_ustringshare_strlen(const Eina_Unicode *str) EINA_PURE EINA_WARN_UNUSED_RESULT;
/**
* @brief Dump the contents of the share_common.
*
* This function dumps all strings in the share_common to stdout with a
* DDD: prefix per line and a memory usage summary.
*/
EAPI void eina_ustringshare_dump(void);
static inline Eina_Bool eina_ustringshare_replace(const Eina_Unicode **p_str, const Eina_Unicode *news) EINA_ARG_NONNULL(1);
static inline Eina_Bool eina_ustringshare_replace_length(const Eina_Unicode **p_str, const Eina_Unicode *news, unsigned int slen) EINA_ARG_NONNULL(1);
#include "eina_inline_ustringshare.x"
/**
* @}
*/
/**
* @}
*/
#endif /* EINA_STRINGSHARE_H_ */