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efl/legacy/eina/src/lib/eina_stringshare.c

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/*
* vim:ts=8:sw=3:sts=8:noexpandtab:cino=>5n-3f0^-2{2
*/
/* EINA - EFL data type library
* Copyright (C) 2002-2008 Carsten Haitzler,
* Jorge Luis Zapata Muga,
* Cedric Bail,
* Gustavo Sverzut Barbieri
*
* 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.
*/
/**
* @page tutorial_stringshare_page Stringshare Tutorial
*
* to be written...
*
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_EVIL
# include <Evil.h>
#endif
#include "eina_stringshare.h"
#include "eina_hash.h"
#include "eina_rbtree.h"
#include "eina_error.h"
#include "eina_private.h"
#include "eina_magic.h"
#include "eina_safety_checks.h"
/*============================================================================*
* Local *
*============================================================================*/
/**
* @cond LOCAL
*/
#define EINA_STRINGSHARE_BUCKETS 256
#define EINA_STRINGSHARE_MASK 0xFF
#define EINA_MAGIC_CHECK_STRINGSHARE_HEAD(d, ...) \
do { \
if (!EINA_MAGIC_CHECK((d), EINA_MAGIC_STRINGSHARE_HEAD)) \
{ \
EINA_MAGIC_FAIL((d), EINA_MAGIC_STRINGSHARE_HEAD); \
return __VA_ARGS__; \
} \
} while (0);
#define EINA_MAGIC_CHECK_STRINGSHARE_NODE(d) \
do { \
if (!EINA_MAGIC_CHECK((d), EINA_MAGIC_STRINGSHARE_NODE)) \
EINA_MAGIC_FAIL((d), EINA_MAGIC_STRINGSHARE_NODE); \
} while (0);
typedef struct _Eina_Stringshare Eina_Stringshare;
typedef struct _Eina_Stringshare_Node Eina_Stringshare_Node;
typedef struct _Eina_Stringshare_Head Eina_Stringshare_Head;
struct _Eina_Stringshare
{
Eina_Stringshare_Head *buckets[EINA_STRINGSHARE_BUCKETS];
EINA_MAGIC
};
struct _Eina_Stringshare_Node
{
Eina_Stringshare_Node *next;
EINA_MAGIC
unsigned short length;
unsigned short references;
char str[];
};
struct _Eina_Stringshare_Head
{
EINA_RBTREE;
EINA_MAGIC
int hash;
#ifdef EINA_STRINGSHARE_USAGE
int population;
#endif
Eina_Stringshare_Node *head;
Eina_Stringshare_Node builtin_node;
};
static Eina_Stringshare *share = NULL;
static int _eina_stringshare_init_count = 0;
static const char _eina_stringshare_single[512] = {
0,0,1,0,2,0,3,0,4,0,5,0,6,0,7,0,8,0,9,0,10,0,11,0,12,0,13,0,14,0,15,0,
16,0,17,0,18,0,19,0,20,0,21,0,22,0,23,0,24,0,25,0,26,0,27,0,28,0,29,0,30,0,
31,0,32,0,33,0,34,0,35,0,36,0,37,0,38,0,39,0,40,0,41,0,42,0,43,0,44,0,45,0,
46,0,47,0,48,0,49,0,50,0,51,0,52,0,53,0,54,0,55,0,56,0,57,0,58,0,59,0,60,0,
61,0,62,0,63,0,64,0,65,0,66,0,67,0,68,0,69,0,70,0,71,0,72,0,73,0,74,0,75,0,
76,0,77,0,78,0,79,0,80,0,81,0,82,0,83,0,84,0,85,0,86,0,87,0,88,0,89,0,90,0,
91,0,92,0,93,0,94,0,95,0,96,0,97,0,98,0,99,0,100,0,101,0,102,0,103,0,104,0,105,0,
106,0,107,0,108,0,109,0,110,0,111,0,112,0,113,0,114,0,115,0,116,0,117,0,118,0,119,0,120,0,
121,0,122,0,123,0,124,0,125,0,126,0,127,0,128,0,129,0,130,0,131,0,132,0,133,0,134,0,135,0,
136,0,137,0,138,0,139,0,140,0,141,0,142,0,143,0,144,0,145,0,146,0,147,0,148,0,149,0,150,0,
151,0,152,0,153,0,154,0,155,0,156,0,157,0,158,0,159,0,160,0,161,0,162,0,163,0,164,0,165,0,
166,0,167,0,168,0,169,0,170,0,171,0,172,0,173,0,174,0,175,0,176,0,177,0,178,0,179,0,180,0,
181,0,182,0,183,0,184,0,185,0,186,0,187,0,188,0,189,0,190,0,191,0,192,0,193,0,194,0,195,0,
196,0,197,0,198,0,199,0,200,0,201,0,202,0,203,0,204,0,205,0,206,0,207,0,208,0,209,0,210,0,
211,0,212,0,213,0,214,0,215,0,216,0,217,0,218,0,219,0,220,0,221,0,222,0,223,0,224,0,225,0,
226,0,227,0,228,0,229,0,230,0,231,0,232,0,233,0,234,0,235,0,236,0,237,0,238,0,239,0,240,0,
241,0,242,0,243,0,244,0,245,0,246,0,247,0,248,0,249,0,250,0,251,0,252,0,253,0,254,0,255,0
};
typedef struct _Eina_Stringshare_Small Eina_Stringshare_Small;
typedef struct _Eina_Stringshare_Small_Bucket Eina_Stringshare_Small_Bucket;
struct _Eina_Stringshare_Small_Bucket
{
/* separate arrays for faster lookups */
const char **strings;
unsigned char *lengths;
unsigned short *references;
int count;
int size;
};
struct _Eina_Stringshare_Small
{
Eina_Stringshare_Small_Bucket *buckets[256];
};
#define EINA_STRINGSHARE_SMALL_BUCKET_STEP 8
static Eina_Stringshare_Small _eina_small_share;
#ifdef EINA_STRINGSHARE_USAGE
typedef struct _Eina_Stringshare_Population Eina_Stringshare_Population;
struct _Eina_Stringshare_Population
{
int count;
int max;
};
static Eina_Stringshare_Population population = { 0, 0 };
static Eina_Stringshare_Population population_group[4] =
{
{ 0, 0 },
{ 0, 0 },
{ 0, 0 },
{ 0, 0 }
};
static int max_node_population = 0;
static void
_eina_stringshare_population_init(void)
{
unsigned int i;
for (i = 0; i < sizeof (population_group) / sizeof (population_group[0]); ++i)
{
population_group[i].count = 0;
population_group[i].max = 0;
}
}
static void
_eina_stringshare_population_shutdown(void)
{
unsigned int i;
max_node_population = 0;
population.count = 0;
population.max = 0;
for (i = 0; i < sizeof (population_group) / sizeof (population_group[0]); ++i)
{
population_group[i].count = 0;
population_group[i].max = 0;
}
}
static void
_eina_stringshare_population_stats(void)
{
unsigned int i;
fprintf(stderr, "eina stringshare statistic:\n");
fprintf(stderr, " * maximum shared strings : %i\n", population.max);
fprintf(stderr, " * maximum shared strings per node : %i\n", max_node_population);
for (i = 0; i < sizeof (population_group) / sizeof (population_group[0]); ++i)
fprintf(stderr, "DDD: %i strings of length %i, max strings: %i\n", population_group[i].count, i, population_group[i].max);
}
static void
_eina_stringshare_population_add(int slen)
{
population.count++;
if (population.count > population.max)
population.max = population.count;
if (slen < 4)
{
population_group[slen].count++;
if (population_group[slen].count > population_group[slen].max)
population_group[slen].max = population_group[slen].count;
}
}
static void
_eina_stringshare_population_del(int slen)
{
population.count--;
if (slen < 4)
population_group[slen].count--;
}
static void
_eina_stringshare_population_head_init(Eina_Stringshare_Head *head)
{
head->population = 1;
}
static void
_eina_stringshare_population_head_add(Eina_Stringshare_Head *head)
{
head->population++;
if (head->population > max_node_population)
max_node_population = head->population;
}
static void
_eina_stringshare_population_head_del(Eina_Stringshare_Head *head)
{
head->population--;
}
#else /* EINA_STRINGSHARE_USAGE undefined */
static void _eina_stringshare_population_init(void) {}
static void _eina_stringshare_population_shutdown(void) {}
static void _eina_stringshare_population_stats(void) {}
static void _eina_stringshare_population_add(__UNUSED__ int slen) {}
static void _eina_stringshare_population_del(__UNUSED__ int slen) {}
static void _eina_stringshare_population_head_init(__UNUSED__ Eina_Stringshare_Head *head) {}
static void _eina_stringshare_population_head_add(__UNUSED__ Eina_Stringshare_Head *head) {}
static void _eina_stringshare_population_head_del(__UNUSED__ Eina_Stringshare_Head *head) {}
#endif
static int
_eina_stringshare_cmp(const Eina_Stringshare_Head *ed, const int *hash, __UNUSED__ int length, __UNUSED__ void *data)
{
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(ed, 0);
return ed->hash - *hash;
}
static Eina_Rbtree_Direction
_eina_stringshare_node(const Eina_Stringshare_Head *left, const Eina_Stringshare_Head *right, __UNUSED__ void *data)
{
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(left, 0);
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(right, 0);
if (left->hash - right->hash < 0)
return EINA_RBTREE_LEFT;
return EINA_RBTREE_RIGHT;
}
static void
_eina_stringshare_head_free(Eina_Stringshare_Head *ed, __UNUSED__ void *data)
{
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(ed);
while (ed->head)
{
Eina_Stringshare_Node *el = ed->head;
ed->head = ed->head->next;
if (el != &ed->builtin_node)
MAGIC_FREE(el);
}
MAGIC_FREE(ed);
}
/**
* @endcond
*/
static Eina_Stringshare_Small _eina_small_share;
static inline int
_eina_stringshare_small_cmp(const Eina_Stringshare_Small_Bucket *bucket, int i, const char *pstr, unsigned char plength)
{
const unsigned char cur_plength = bucket->lengths[i];
const char *cur_pstr;
if (cur_plength > plength)
return 1;
else if (cur_plength < plength)
return -1;
cur_pstr = bucket->strings[i] + 1;
if (cur_pstr[0] > pstr[0])
return 1;
else if (cur_pstr[0] < pstr[0])
return -1;
if (plength == 1)
return 0;
if (cur_pstr[1] > pstr[1])
return 1;
else if (cur_pstr[1] < pstr[1])
return -1;
return 0;
}
static const char *
_eina_stringshare_small_bucket_find(const Eina_Stringshare_Small_Bucket *bucket, const char *str, unsigned char length, int *index)
{
const char *pstr = str + 1; /* skip first letter, it's always the same */
unsigned char plength = length;
int i, low, high;
if (bucket->count == 0)
{
*index = 0;
return NULL;
}
low = 0;
high = bucket->count;
while (low < high)
{
int r;
i = (low + high - 1) / 2;
r = _eina_stringshare_small_cmp(bucket, i, pstr, plength);
if (r > 0)
{
high = i;
}
else if (r < 0)
{
low = i + 1;
}
else
{
*index = i;
return bucket->strings[i];
}
}
*index = low;
return NULL;
}
static Eina_Bool
_eina_stringshare_small_bucket_resize(Eina_Stringshare_Small_Bucket *bucket, int size)
{
void *tmp;
tmp = realloc((void*)bucket->strings, size * sizeof(bucket->strings[0]));
if (!tmp)
{
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return 0;
}
bucket->strings = tmp;
tmp = realloc(bucket->lengths, size * sizeof(bucket->lengths[0]));
if (!tmp)
{
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return 0;
}
bucket->lengths = tmp;
tmp = realloc(bucket->references, size * sizeof(bucket->references[0]));
if (!tmp)
{
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return 0;
}
bucket->references = tmp;
bucket->size = size;
return 1;
}
static const char *
_eina_stringshare_small_bucket_insert_at(Eina_Stringshare_Small_Bucket **p_bucket, const char *str, unsigned char length, int index)
{
Eina_Stringshare_Small_Bucket *bucket = *p_bucket;
int todo, off;
char *snew;
if (!bucket)
{
*p_bucket = bucket = calloc(1, sizeof(*bucket));
if (!bucket)
{
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return NULL;
}
}
if (bucket->count + 1 >= bucket->size)
{
int size = bucket->size + EINA_STRINGSHARE_SMALL_BUCKET_STEP;
if (!_eina_stringshare_small_bucket_resize(bucket, size))
return NULL;
}
snew = malloc(length + 1);
if (!snew)
{
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return NULL;
}
memcpy(snew, str, length);
snew[length] = '\0';
off = index + 1;
todo = bucket->count - index;
if (todo > 0)
{
memmove((void *)(bucket->strings + off), bucket->strings + index,
todo * sizeof(bucket->strings[0]));
memmove(bucket->lengths + off, bucket->lengths + index,
todo * sizeof(bucket->lengths[0]));
memmove(bucket->references + off, bucket->references + index,
todo * sizeof(bucket->references[0]));
}
bucket->strings[index] = snew;
bucket->lengths[index] = length;
bucket->references[index] = 1;
bucket->count++;
return snew;
}
static void
_eina_stringshare_small_bucket_remove_at(Eina_Stringshare_Small_Bucket **p_bucket, int index)
{
Eina_Stringshare_Small_Bucket *bucket = *p_bucket;
int todo, off;
if (bucket->references[index] > 1)
{
bucket->references[index]--;
return;
}
free((char *)bucket->strings[index]);
if (bucket->count == 1)
{
free((void *)bucket->strings);
free(bucket->lengths);
free(bucket->references);
free(bucket);
*p_bucket = NULL;
return;
}
bucket->count--;
if (index == bucket->count)
goto end;
off = index + 1;
todo = bucket->count - index;
memmove((void *)(bucket->strings + index), bucket->strings + off,
todo * sizeof(bucket->strings[0]));
memmove(bucket->lengths + index, bucket->lengths + off,
todo * sizeof(bucket->lengths[0]));
memmove(bucket->references + index, bucket->references + off,
todo * sizeof(bucket->references[0]));
end:
if (bucket->count + EINA_STRINGSHARE_SMALL_BUCKET_STEP < bucket->size)
{
int size = bucket->size - EINA_STRINGSHARE_SMALL_BUCKET_STEP;
_eina_stringshare_small_bucket_resize(bucket, size);
}
}
static const char *
_eina_stringshare_small_add(const char *str, unsigned char length)
{
Eina_Stringshare_Small_Bucket **bucket;
int i;
bucket = _eina_small_share.buckets + (unsigned char)str[0];
if (!*bucket)
i = 0;
else
{
const char *ret;
ret = _eina_stringshare_small_bucket_find(*bucket, str, length, &i);
if (ret)
{
(*bucket)->references[i]++;
return ret;
}
}
return _eina_stringshare_small_bucket_insert_at(bucket, str, length, i);
}
static void
_eina_stringshare_small_del(const char *str, unsigned char length)
{
Eina_Stringshare_Small_Bucket **bucket;
const char *ret;
int i;
bucket = _eina_small_share.buckets + (unsigned char)str[0];
if (!*bucket)
goto error;
ret = _eina_stringshare_small_bucket_find(*bucket, str, length, &i);
if (!ret)
goto error;
_eina_stringshare_small_bucket_remove_at(bucket, i);
return;
error:
EINA_ERROR_PWARN("EEEK trying to del non-shared stringshare \"%s\"\n", str);
if (getenv("EINA_ERROR_ABORT")) abort();
}
static void
_eina_stringshare_small_init(void)
{
memset(&_eina_small_share, 0, sizeof(_eina_small_share));
}
static void
_eina_stringshare_small_shutdown(void)
{
Eina_Stringshare_Small_Bucket **p_bucket, **p_bucket_end;
p_bucket = _eina_small_share.buckets;
p_bucket_end = p_bucket + 256;
for (; p_bucket < p_bucket_end; p_bucket++)
{
Eina_Stringshare_Small_Bucket *bucket = *p_bucket;
char **s, **s_end;
if (!bucket)
continue;
s = (char **)bucket->strings;
s_end = s + bucket->count;
for (; s < s_end; s++)
free(*s);
free((void *)bucket->strings);
free(bucket->lengths);
free(bucket->references);
free(bucket);
*p_bucket = NULL;
}
}
static void
_eina_stringshare_node_init(Eina_Stringshare_Node *node, const char *str, int slen)
{
EINA_MAGIC_SET(node, EINA_MAGIC_STRINGSHARE_NODE);
node->references = 1;
node->length = slen;
memcpy(node->str, str, slen);
node->str[slen] = '\0';
}
static Eina_Stringshare_Head *
_eina_stringshare_head_alloc(int slen)
{
Eina_Stringshare_Head *head, t;
const size_t head_size = (char *)&(t.builtin_node.str) - (char *)&t;
head = malloc(head_size + slen + 1);
if (!head)
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return head;
}
static const char *
_eina_stringshare_add_head(Eina_Stringshare_Head **p_bucket, int hash, const char *str, int slen)
{
Eina_Rbtree **p_tree = (Eina_Rbtree **)p_bucket;
Eina_Stringshare_Head *head;
head = _eina_stringshare_head_alloc(slen);
if (!head)
return NULL;
EINA_MAGIC_SET(head, EINA_MAGIC_STRINGSHARE_HEAD);
head->hash = hash;
head->head = &head->builtin_node;
_eina_stringshare_node_init(head->head, str, slen);
head->head->next = NULL;
_eina_stringshare_population_head_init(head);
*p_tree = eina_rbtree_inline_insert
(*p_tree, EINA_RBTREE_GET(head),
EINA_RBTREE_CMP_NODE_CB(_eina_stringshare_node), NULL);
return head->head->str;
}
static void
_eina_stringshare_del_head(Eina_Stringshare_Head **p_bucket, Eina_Stringshare_Head *head)
{
Eina_Rbtree **p_tree = (Eina_Rbtree **)p_bucket;
*p_tree = eina_rbtree_inline_remove
(*p_tree, EINA_RBTREE_GET(head),
EINA_RBTREE_CMP_NODE_CB(_eina_stringshare_node), NULL);
MAGIC_FREE(head);
}
static inline Eina_Bool
_eina_stringshare_node_eq(const Eina_Stringshare_Node *node, const char *str, int slen)
{
return ((node->length == slen) &&
(memcmp(node->str, str, slen) == 0));
}
static Eina_Stringshare_Node *
_eina_stringshare_head_find(Eina_Stringshare_Head *head, const char *str, int slen)
{
Eina_Stringshare_Node *node, *prev;
node = head->head;
if (_eina_stringshare_node_eq(node, str, slen))
return node;
prev = node;
node = node->next;
for (; node != NULL; prev = node, node = node->next)
if (_eina_stringshare_node_eq(node, str, slen))
{
/* promote node, make hot items be at the beginning */
prev->next = node->next;
node->next = head->head;
head->head = node;
return node;
}
return NULL;
}
static Eina_Bool
_eina_stringshare_head_remove_node(Eina_Stringshare_Head *head, const Eina_Stringshare_Node *node)
{
Eina_Stringshare_Node *cur, *prev;
if (head->head == node)
{
head->head = node->next;
return 1;
}
prev = head->head;
cur = head->head->next;
for (; cur != NULL; prev = cur, cur = cur->next)
if (cur == node)
{
prev->next = cur->next;
return 1;
}
return 0;
}
static Eina_Stringshare_Head *
_eina_stringshare_find_hash(Eina_Stringshare_Head *bucket, int hash)
{
return (Eina_Stringshare_Head*) eina_rbtree_inline_lookup
(EINA_RBTREE_GET(bucket), &hash, 0,
EINA_RBTREE_CMP_KEY_CB(_eina_stringshare_cmp), NULL);
}
static Eina_Stringshare_Node *
_eina_stringshare_node_alloc(int slen)
{
Eina_Stringshare_Node *node, t;
const size_t node_size = (char *)&(t.str) - (char *)&t;
node = malloc(node_size + slen + 1);
if (!node)
eina_error_set(EINA_ERROR_OUT_OF_MEMORY);
return node;
}
/*============================================================================*
* Global *
*============================================================================*/
/*============================================================================*
* API *
*============================================================================*/
/**
* @addtogroup Eina_Stringshare_Group 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_stringshare_page.
*
* @{
*/
/**
* @brief Initialize the eina stringshare internal structure.
*
* @return 1 or greater on success, 0 on error.
*
* This function allocates the memory needed by the stringshare
* internal structure and sets up the error module of Eina. It is also
* called by eina_init(). It returns 0 on failure, otherwise it
* returns the number of times it has already been called.
*/
EAPI int
eina_stringshare_init(void)
{
/*
* No strings have been loaded at this point, so create the hash
* table for storing string info for later.
*/
if (!_eina_stringshare_init_count)
{
share = calloc(1, sizeof(Eina_Stringshare));
if (!share)
return 0;
if (!eina_error_init())
{
fprintf(stderr, "Could not initialize eina error module.\n");
return 0;
}
if (!eina_magic_string_init())
{
EINA_ERROR_PERR("ERROR: Could not initialize eina magic string module.\n");
eina_error_shutdown();
return 0;
}
eina_magic_string_set(EINA_MAGIC_STRINGSHARE,
"Eina Stringshare");
eina_magic_string_set(EINA_MAGIC_STRINGSHARE_HEAD,
"Eina Stringshare Head");
eina_magic_string_set(EINA_MAGIC_STRINGSHARE_NODE,
"Eina Stringshare Node");
EINA_MAGIC_SET(share, EINA_MAGIC_STRINGSHARE);
_eina_stringshare_small_init();
_eina_stringshare_population_init();
}
return ++_eina_stringshare_init_count;
}
/**
* @brief Shut down the eina stringshare internal structures
*
* @return 0 when the stringshare module is completely shut down, 1 or
* greater otherwise.
*
* This function frees the memory allocated by eina_stringshare_init()
* and shuts down the error module. It is also called by
* eina_shutdown(). It returns 0 when it is called the same number of
* times than eina_stringshare_init().
*/
EAPI int
eina_stringshare_shutdown(void)
{
unsigned int i;
_eina_stringshare_population_stats();
--_eina_stringshare_init_count;
if (!_eina_stringshare_init_count)
{
/* remove any string still in the table */
for (i = 0; i < EINA_STRINGSHARE_BUCKETS; i++)
{
eina_rbtree_delete(EINA_RBTREE_GET(share->buckets[i]), EINA_RBTREE_FREE_CB(_eina_stringshare_head_free), NULL);
share->buckets[i] = NULL;
}
MAGIC_FREE(share);
_eina_stringshare_population_shutdown();
_eina_stringshare_small_shutdown();
eina_magic_string_shutdown();
eina_error_shutdown();
}
return _eina_stringshare_init_count;
}
/**
* @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 give the
* exact given size. This can be used to stringshare part of a larger
* buffer or substring.
*
* @note it's not possible to have more than 65k references or strings
* bigger than 65k since we use 'unsigned short' to save space.
*
* @see eina_stringshare_add()
*/
EAPI const char *
eina_stringshare_add_length(const char *str, unsigned int slen)
{
Eina_Stringshare_Head **p_bucket, *ed;
Eina_Stringshare_Node *el;
int hash_num, hash;
if (!str) return NULL;
_eina_stringshare_population_add(slen);
if (slen == 0)
return "";
else if (slen == 1)
return _eina_stringshare_single + ((*str) << 1);
else if (slen < 4)
return _eina_stringshare_small_add(str, slen);
hash = eina_hash_superfast(str, slen);
hash_num = hash & 0xFF;
hash = (hash >> 8) & EINA_STRINGSHARE_MASK;
p_bucket = share->buckets + hash_num;
ed = _eina_stringshare_find_hash(*p_bucket, hash);
if (!ed)
return _eina_stringshare_add_head(p_bucket, hash, str, slen);
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(ed, NULL);
el = _eina_stringshare_head_find(ed, str, slen);
if (el)
{
EINA_MAGIC_CHECK_STRINGSHARE_NODE(el);
el->references++;
return el->str;
}
el = _eina_stringshare_node_alloc(slen);
if (!el)
return NULL;
_eina_stringshare_node_init(el, str, slen);
el->next = ed->head;
ed->head = el;
_eina_stringshare_population_head_add(ed);
return el->str;
}
/**
* @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 @a 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.
*
* @note it's not possible to have more than 65k references or strings
* bigger than 65k since we use 'unsigned short' to save space.
*
* @see eina_stringshare_add_length()
*/
EAPI const char *
eina_stringshare_add(const char *str)
{
int slen;
if (!str) return NULL;
if (str[0] == '\0') slen = 0;
else if (str[1] == '\0') slen = 1;
else if (str[2] == '\0') slen = 2;
else if (str[3] == '\0') slen = 3;
else slen = 3 + (int)strlen(str + 3);
return eina_stringshare_add_length(str, slen);
}
static Eina_Stringshare_Node *
_eina_stringshare_node_from_str(const char *str)
{
Eina_Stringshare_Node *node, t;
const size_t offset = (char *)&(t.str) - (char *)&t;
node = (Eina_Stringshare_Node *)(str - offset);
EINA_MAGIC_CHECK_STRINGSHARE_NODE(node);
return node;
}
/**
* Increment references of the given shared string.
*
* This is similar to eina_stringshare_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_stringshare_add().
*
* There is no unref since this is the work of eina_stringshare_del().
*/
EAPI const char *
eina_stringshare_ref(const char *str)
{
Eina_Stringshare_Node *node;
int slen;
if (!str) return NULL;
/* special cases */
if (str[0] == '\0') slen = 0;
else if (str[1] == '\0') slen = 1;
else if (str[2] == '\0') slen = 2;
else if (str[3] == '\0') slen = 3;
else slen = 4; /* handled later */
if (slen < 2)
{
_eina_stringshare_population_add(slen);
return str;
}
else if (slen < 4)
{
_eina_stringshare_population_add(slen);
return _eina_stringshare_small_add(str, slen);
}
node = _eina_stringshare_node_from_str(str);
node->references++;
_eina_stringshare_population_add(node->length);
return 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 NULL, the function returns
* immediatly.
*
* Note that if the given pointer is not shared or NULL, bad things
* will happen, likely a segmentation fault.
*/
EAPI void
eina_stringshare_del(const char *str)
{
Eina_Stringshare_Head *ed;
Eina_Stringshare_Head **p_bucket;
Eina_Stringshare_Node *node;
int hash_num, slen, hash;
if (!str) return;
/* special cases */
if (str[0] == '\0') slen = 0;
else if (str[1] == '\0') slen = 1;
else if (str[2] == '\0') slen = 2;
else if (str[3] == '\0') slen = 3;
else slen = 4; /* handled later */
_eina_stringshare_population_del(slen);
if (slen < 2)
return;
else if (slen < 4)
{
_eina_stringshare_small_del(str, slen);
return;
}
node = _eina_stringshare_node_from_str(str);
if (node->references > 1)
{
node->references--;
return;
}
node->references = 0;
slen = node->length;
hash = eina_hash_superfast(str, slen);
hash_num = hash & 0xFF;
hash = (hash >> 8) & EINA_STRINGSHARE_MASK;
p_bucket = share->buckets + hash_num;
ed = _eina_stringshare_find_hash(*p_bucket, hash);
if (!ed)
goto on_error;
EINA_MAGIC_CHECK_STRINGSHARE_HEAD(ed);
if (!_eina_stringshare_head_remove_node(ed, node))
goto on_error;
if (node != &ed->builtin_node)
MAGIC_FREE(node);
if (!ed->head)
_eina_stringshare_del_head(p_bucket, ed);
else
_eina_stringshare_population_head_del(ed);
return;
on_error:
/* possible segfault happened before here, but... */
EINA_ERROR_PWARN("EEEK trying to del non-shared stringshare \"%s\"\n", str);
if (getenv("EINA_ERROR_ABORT")) abort();
}
/**
* @brief Note that the given string @b must be shared.
*
* @param str the shared string to know the length. It is safe to
* give NULL, in that case -1 is returned.
*
* This function is a cheap way to known the length of a shared
* string. Note that if the given pointer is not shared or NULL, bad
* things will happen, likely a segmentation fault. If in doubt, try
* strlen().
*/
EAPI int
eina_stringshare_strlen(const char *str)
{
const Eina_Stringshare_Node *node;
if (!str)
return -1;
/* special cases */
if (str[0] == '\0') return 0;
if (str[1] == '\0') return 1;
if (str[2] == '\0') return 2;
if (str[3] == '\0') return 3;
node = _eina_stringshare_node_from_str(str);
return node->length;
}
struct dumpinfo
{
int used, saved, dups, unique;
};
static void
_eina_stringshare_small_bucket_dump(Eina_Stringshare_Small_Bucket *bucket, struct dumpinfo *di)
{
const char **s = bucket->strings;
unsigned char *l = bucket->lengths;
unsigned short *r = bucket->references;
int i;
di->used += sizeof(*bucket);
di->used += bucket->count * sizeof(*s);
di->used += bucket->count * sizeof(*l);
di->used += bucket->count * sizeof(*r);
di->unique += bucket->count;
for (i = 0; i < bucket->count; i++, s++, l++, r++)
{
int dups;
printf("DDD: %5hhu %5hu '%s'\n", *l, *r, *s);
dups = (*r - 1);
di->used += *l;
di->saved += *l * dups;
di->dups += dups;
}
}
static void
_eina_stringshare_small_dump(struct dumpinfo *di)
{
Eina_Stringshare_Small_Bucket **p_bucket, **p_bucket_end;
p_bucket = _eina_small_share.buckets;
p_bucket_end = p_bucket + 256;
for (; p_bucket < p_bucket_end; p_bucket++)
{
Eina_Stringshare_Small_Bucket *bucket = *p_bucket;
if (!bucket)
continue;
_eina_stringshare_small_bucket_dump(bucket, di);
}
}
static Eina_Bool
eina_iterator_array_check(const Eina_Rbtree *rbtree __UNUSED__, Eina_Stringshare_Head *head, struct dumpinfo *fdata)
{
Eina_Stringshare_Node *node;
fdata->used += sizeof(Eina_Stringshare_Head);
for (node = head->head; node; node = node->next)
{
printf("DDD: %5i %5i ", node->length, node->references);
printf("'%s'\n", ((char *)node) + sizeof(Eina_Stringshare_Node));
fdata->used += sizeof(Eina_Stringshare_Node);
fdata->used += node->length;
fdata->saved += (node->references - 1) * node->length;
fdata->dups += node->references - 1;
fdata->unique++;
}
return EINA_TRUE;
}
/**
* @brief Dump the contents of the stringshare.
*
* This function dumps all strings in the stringshare to stdout with a
* DDD: prefix per line and a memory usage summary.
*/
EAPI void
eina_stringshare_dump(void)
{
Eina_Iterator *it;
unsigned int i;
struct dumpinfo di;
if (!share) return;
di.used = sizeof (_eina_stringshare_single);
di.saved = 0;
di.dups = 0;
di.unique = 0;
printf("DDD: len ref string\n");
printf("DDD:-------------------\n");
_eina_stringshare_small_dump(&di);
for (i = 0; i < EINA_STRINGSHARE_BUCKETS; i++)
{
if (!share->buckets[i]) continue;
// printf("DDD: BUCKET # %i (HEAD=%i, NODE=%i)\n", i,
// sizeof(Eina_Stringshare_Head), sizeof(Eina_Stringshare_Node));
it = eina_rbtree_iterator_prefix((Eina_Rbtree *)share->buckets[i]);
eina_iterator_foreach(it, EINA_EACH(eina_iterator_array_check), &di);
eina_iterator_free(it);
}
#ifdef EINA_STRINGSHARE_USAGE
/* One character strings are not counted in the hash. */
di.saved += population_group[0].count * sizeof(char);
di.saved += population_group[1].count * sizeof(char) * 2;
#endif
printf("DDD:-------------------\n");
printf("DDD: usage (bytes) = %i, saved = %i (%3.0f%%)\n",
di.used, di.saved, di.used ? (di.saved * 100.0 / di.used) : 0.0);
printf("DDD: unique: %d, duplicates: %d (%3.0f%%)\n",
di.unique, di.dups, di.unique ? (di.dups * 100.0 / di.unique) : 0.0);
#ifdef EINA_STRINGSHARE_USAGE
printf("DDD: Allocated strings: %i\n", population.count);
printf("DDD: Max allocated strings: %i\n", population.max);
for (i = 0; i < sizeof (population_group) / sizeof (population_group[0]); ++i)
fprintf(stderr, "DDD: %i strings of length %i, max strings: %i\n", population_group[i].count, i, population_group[i].max);
#endif
}
/**
* @}
*/
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