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/*
* Implementation of an efficient array to store that we pinged something.
*/
/*
* Copyright © 2016-2017 The TokTok team.
* Copyright © 2014 Tox project.
*
* This file is part of Tox, the free peer to peer instant messenger.
*
* Tox 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.
*
* Tox 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 Tox. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "ping_array.h"
#include "crypto_core.h"
#include "util.h"
typedef struct {
void *data;
uint32_t length;
uint64_t time;
uint64_t ping_id;
} Ping_Array_Entry;
struct Ping_Array {
Ping_Array_Entry *entries;
uint32_t last_deleted; /* number representing the next entry to be deleted. */
uint32_t last_added; /* number representing the last entry to be added. */
uint32_t total_size; /* The length of entries */
uint32_t timeout; /* The timeout after which entries are cleared. */
};
/* Initialize a Ping_Array.
* size represents the total size of the array and should be a power of 2.
* timeout represents the maximum timeout in seconds for the entry.
*
* return 0 on success.
* return -1 on failure.
*/
Ping_Array *ping_array_new(uint32_t size, uint32_t timeout)
{
if (size == 0 || timeout == 0) {
return nullptr;
}
Ping_Array *empty_array = (Ping_Array *)calloc(1, sizeof(Ping_Array));
if (empty_array == nullptr) {
return nullptr;
}
empty_array->entries = (Ping_Array_Entry *)calloc(size, sizeof(Ping_Array_Entry));
if (empty_array->entries == nullptr) {
free(empty_array);
return nullptr;
}
empty_array->last_deleted = empty_array->last_added = 0;
empty_array->total_size = size;
empty_array->timeout = timeout;
return empty_array;
}
static void clear_entry(Ping_Array *array, uint32_t index)
{
free(array->entries[index].data);
array->entries[index].data = nullptr;
array->entries[index].length =
array->entries[index].time =
array->entries[index].ping_id = 0;
}
/* Free all the allocated memory in a Ping_Array.
*/
void ping_array_kill(Ping_Array *array)
{
while (array->last_deleted != array->last_added) {
uint32_t index = array->last_deleted % array->total_size;
clear_entry(array, index);
++array->last_deleted;
}
free(array->entries);
free(array);
}
/* Clear timed out entries.
*/
static void ping_array_clear_timedout(Ping_Array *array)
{
while (array->last_deleted != array->last_added) {
uint32_t index = array->last_deleted % array->total_size;
if (!is_timeout(array->entries[index].time, array->timeout)) {
break;
}
clear_entry(array, index);
++array->last_deleted;
}
}
/* Add a data with length to the Ping_Array list and return a ping_id.
*
* return ping_id on success.
* return 0 on failure.
*/
uint64_t ping_array_add(Ping_Array *array, const uint8_t *data, uint32_t length)
{
ping_array_clear_timedout(array);
uint32_t index = array->last_added % array->total_size;
if (array->entries[index].data != nullptr) {
array->last_deleted = array->last_added - array->total_size;
clear_entry(array, index);
}
array->entries[index].data = malloc(length);
if (array->entries[index].data == nullptr) {
return 0;
}
memcpy(array->entries[index].data, data, length);
array->entries[index].length = length;
array->entries[index].time = unix_time();
++array->last_added;
uint64_t ping_id = random_u64();
ping_id /= array->total_size;
ping_id *= array->total_size;
ping_id += index;
if (ping_id == 0) {
ping_id += array->total_size;
}
array->entries[index].ping_id = ping_id;
return ping_id;
}
/* Check if ping_id is valid and not timed out.
*
* On success, copies the data into data of length,
*
* return length of data copied on success.
* return -1 on failure.
*/
int32_t ping_array_check(Ping_Array *array, uint8_t *data, size_t length, uint64_t ping_id)
{
if (ping_id == 0) {
return -1;
}
uint32_t index = ping_id % array->total_size;
if (array->entries[index].ping_id != ping_id) {
return -1;
}
if (is_timeout(array->entries[index].time, array->timeout)) {
return -1;
}
if (array->entries[index].length > length) {
return -1;
}
if (array->entries[index].data == nullptr) {
return -1;
}
memcpy(data, array->entries[index].data, array->entries[index].length);
uint32_t len = array->entries[index].length;
clear_entry(array, index);
return len;
}
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