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/*
* Copyright (c) 2014, Linaro Limited
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdlib.h>
#include <string.h>
#include <kernel/handle.h>
/*
* Define the initial capacity of the database. It should be a low number
* multiple of 2 since some databases a likely to only use a few handles.
* Since the algorithm is to doubles up when growing it shouldn't cause a
* noticable overhead on large databases.
*/
#define HANDLE_DB_INITIAL_MAX_PTRS 4
void handle_db_destroy(struct handle_db *db)
{
if (db) {
free(db->ptrs);
db->ptrs = NULL;
db->max_ptrs = 0;
}
}
int handle_get(struct handle_db *db, void *ptr)
{
size_t n;
void *p;
size_t new_max_ptrs;
if (!db || !ptr)
return -1;
/* Try to find an empty location */
for (n = 0; n < db->max_ptrs; n++) {
if (!db->ptrs[n]) {
db->ptrs[n] = ptr;
return n;
}
}
/* No location available, grow the ptrs array */
if (db->max_ptrs)
new_max_ptrs = db->max_ptrs * 2;
else
new_max_ptrs = HANDLE_DB_INITIAL_MAX_PTRS;
p = realloc(db->ptrs, new_max_ptrs * sizeof(void *));
if (!p)
return -1;
db->ptrs = p;
memset(db->ptrs + db->max_ptrs, 0,
(new_max_ptrs - db->max_ptrs) * sizeof(void *));
db->max_ptrs = new_max_ptrs;
/* Since n stopped at db->max_ptrs there is an empty location there */
db->ptrs[n] = ptr;
return n;
}
void *handle_put(struct handle_db *db, int handle)
{
void *p;
if (!db || handle < 0 || (size_t)handle >= db->max_ptrs)
return NULL;
p = db->ptrs[handle];
db->ptrs[handle] = NULL;
return p;
}
void *handle_lookup(struct handle_db *db, int handle)
{
if (!db || handle < 0 || (size_t)handle >= db->max_ptrs)
return NULL;
return db->ptrs[handle];
}
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