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/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <pthread.h>
#include <assert.h>
#include <stdio.h>
#include <urcu.h>
//#include "common.h"
#include "common/dynamic-array.h"
#ifndef ERR_ALLOC_FAILED
#define ERR_ALLOC_FAILED fprintf(stderr, "Allocation failed at %s:%d\n", \
__FILE__, __LINE__)
#endif
//#define DA_DEBUG
#ifndef dbg_da
#ifdef DA_DEBUG
#define dbg_da(msg...) fprintf(stderr, msg)
#else
#define dbg_da(msg...)
#endif
#endif
/*----------------------------------------------------------------------------*/
/* Private functions */
/*----------------------------------------------------------------------------*/
enum da_resize_type {
DA_LARGER, DA_SMALLER
};
typedef enum da_resize_type da_resize_type_t;
/*----------------------------------------------------------------------------*/
/*!
* \retval 1 On success.
* \retval -1 On failure.
*/
static int da_resize(da_array_t *array, da_resize_type_t type)
{
dbg_da("da_resize(): array pointer: %p, items pointer: %p\n", array,
array->items);
unsigned new_size = ((type == DA_LARGER)
? (array->allocated *= 2)
: (array->allocated /= 2));
void *new_items = malloc(new_size * array->item_size);
if (new_items == NULL) {
ERR_ALLOC_FAILED;
return -1;
}
dbg_da("Place for new items: %p\n", new_items);
// copy the contents from the old array to the new
memcpy(new_items, array->items, array->count * array->item_size);
// do RCU update
void *old_items = rcu_xchg_pointer(&array->items, new_items);
array->allocated = new_size;
dbg_da("Old items pointer: %p\n", old_items);
// wait for readers to finish
synchronize_rcu();
// deallocate the old array
dbg_da("RCU synchronized, deallocating old items array at address %p."
"\n", old_items);
free(old_items);
return 1;
}
/*----------------------------------------------------------------------------*/
/* Public functions */
/*----------------------------------------------------------------------------*/
da_array_t *da_create(unsigned count, size_t item_size)
{
da_array_t *a = (da_array_t *)malloc(sizeof(da_array_t));
if (a == NULL) {
ERR_ALLOC_FAILED;
return NULL;
}
da_initialize(a, count, item_size);
return a;
}
/*----------------------------------------------------------------------------*/
int da_initialize(da_array_t *array, unsigned count, size_t item_size)
{
assert(array != NULL);
pthread_mutex_init(&array->mtx, NULL);
pthread_mutex_lock(&array->mtx);
array->items = malloc(count * item_size);
if (array->items == NULL) {
array->allocated = 0;
array->count = 0;
ERR_ALLOC_FAILED;
return -1;
}
array->allocated = count;
array->count = 0;
array->item_size = item_size;
memset(array->items, 0, count * item_size);
pthread_mutex_unlock(&array->mtx);
return 0;
}
/*----------------------------------------------------------------------------*/
int da_reserve(da_array_t *array, unsigned count)
{
pthread_mutex_lock(&array->mtx);
unsigned res = 0;
assert(array->allocated >= array->count);
if ((array->allocated - array->count) >= count) {
dbg_da("Enough place in the array, no resize needed.\n");
res = 0;
} else {
dbg_da("Resizing array.\n");
res = da_resize(array, DA_LARGER);
}
pthread_mutex_unlock(&array->mtx);
return res;
}
/*----------------------------------------------------------------------------*/
int da_occupy(da_array_t *array, unsigned count)
{
pthread_mutex_lock(&array->mtx);
unsigned res = 0;
assert(array->allocated >= array->count);
if ((array->allocated - array->count) < count) {
dbg_da("Not enough place to occupy.\n");
res = -1;
} else {
array->count += count;
}
pthread_mutex_unlock(&array->mtx);
return res;
}
/*----------------------------------------------------------------------------*/
unsigned da_try_reserve(const da_array_t *array, unsigned count)
{
assert(array->allocated >= array->count);
if ((array->allocated - array->count) >= count) {
return 0;
}
return 1;
}
/*----------------------------------------------------------------------------*/
void da_release(da_array_t *array, unsigned count)
{
pthread_mutex_lock(&array->mtx);
assert(array->allocated >= array->count);
assert(array->count >= count);
dbg_da("Decreasing count of items in array.\n");
array->count -= count;
pthread_mutex_unlock(&array->mtx);
}
/*----------------------------------------------------------------------------*/
void da_destroy(da_array_t *array)
{
pthread_mutex_lock(&array->mtx);
void *old_items = rcu_dereference(array->items);
rcu_set_pointer(&array->items, NULL);
pthread_mutex_unlock(&array->mtx);
synchronize_rcu();
free(old_items);
pthread_mutex_destroy(&array->mtx);
}
/*----------------------------------------------------------------------------*/
void *da_get_items(const da_array_t *array)
{
return array->items;
}
/*----------------------------------------------------------------------------*/
unsigned da_get_count(const da_array_t *array)
{
return array->count;
}
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