/**
* mds — A micro-display server
* Copyright © 2014, 2015, 2016, 2017 Mattias Andrée (maandree@kth.se)
*
* 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 "fd-table.h"
#include "macros.h"
#include <stdlib.h>
#include <string.h>
#include <errno.h>
/**
* Create a fd table
*
* @param this Memory slot in which to store the new fd table
* @param initial_capacity The initial capacity of the table
* @return Non-zero on error, `errno` will have been set accordingly
*/
int
fd_table_create_tuned(fd_table_t *restrict this, size_t initial_capacity)
{
size_t bitcap;
this->capacity = initial_capacity ? initial_capacity : 1;
this->size = 0;
this->values = NULL;
this->used = NULL;
this->value_comparator = NULL;
/* It is important that both allocations are done with calloc:
`this->used` must set all keys as unused at the initial state,
`this->values` must be initialised for marshaling and it helps
the time overhead of `fd_table_contains_value`. */
bitcap = (this->capacity + 63) / 64;
fail_if (xcalloc(this->used, bitcap, size_t));
fail_if (xcalloc(this->values, this->capacity, size_t));
return 0;
fail:
return -1;
}
/**
* Release all resources in a fd table, should
* be done even if construction fails
*
* @param this The fd table
* @param keys_freer Function that frees a key, `NULL` if keys should not be freed
* @param values_freer Function that frees a value, `NULL` if value should not be freed
*/
void
fd_table_destroy(fd_table_t *restrict this, free_func *key_freer, free_func *value_freer)
{
size_t i;
if ((key_freer || value_freer) && this->used && this->values) {
for (i = 0; i < this->capacity; i++) {
if (this->used[i / 64] & ((uint64_t)1 << (i % 64))) {
if (key_freer) key_freer(i);
if (value_freer) value_freer(this->values[i]);
}
}
}
free(this->values);
free(this->used);
}
/**
* Check whether a value is stored in the table
*
* @param this The fd table
* @param value The value
* @return Whether the value is stored in the table
*/
int
fd_table_contains_value(const fd_table_t *restrict this, size_t value)
{
size_t i;
if (!this->value_comparator) {
for (i = 0; i < this->capacity; i++)
if (this->values[i] == value)
if (this->used[i / 64] & ((uint64_t)1 << (i % 64)))
return 1;
} else {
for (i = 0; i < this->capacity; i++)
if (this->used[i / 64] & ((uint64_t)1 << (i % 64)))
if (this->value_comparator(this->values[i], value))
return 1;
}
return 0;
}
/**
* Check whether a key is used in the table
*
* @param this The fd table
* @param key The key
* @return Whether the key is used
*/
int
fd_table_contains_key(const fd_table_t *restrict this, int key)
{
return (size_t)key < this->capacity && (this->used[key / 64] & ((uint64_t)1 << (key % 64)));
}
/**
* Look up a value in the table
*
* @param this The fd table
* @param key The key associated with the value
* @return The value associated with the key, 0 if the key was not used
*/
size_t
fd_table_get(const fd_table_t *restrict this, int key)
{
return fd_table_contains_key(this, key) ? this->values[key] : 0;
}
/**
* Add an entry to the table
*
* @param this The fd table
* @param key The key of the entry to add
* @param value The value of the entry to add
* @return The previous value associated with the key, 0 if the key was not used.
* 0 will also be returned on error, check the `errno` variable.
*/
size_t
fd_table_put(fd_table_t *restrict this, int key, size_t value)
{
size_t rc, old_bitcap, new_bitcap, *old_values;
uint64_t *old_used;
/* Override current value if the key is already used. */
if (fd_table_contains_key(this, key)) {
rc = fd_table_get(this, key);
this->values[key] = value;
return rc;
}
/* Grow the table if it is too small. */
errno = 0;
if ((size_t)key >= this->capacity) {
old_values = this->values;
if (xrealloc(this->values, this->capacity << 1, size_t)) {
this->values = old_values;
fail_if (1);
}
memset(this->values + this->capacity, 0, this->capacity * sizeof(size_t));
old_bitcap = (this->capacity + 63) / 64;
this->capacity <<= 1;
new_bitcap = (this->capacity + 63) / 64;
if (new_bitcap > old_bitcap) {
old_used = this->used;
if (xrealloc(this->used, new_bitcap, size_t)) {
this->used = old_used;
this->capacity >>= 1;
fail_if (1);
}
memset(this->used + old_bitcap, 0, (new_bitcap - old_bitcap) * sizeof(uint64_t));
}
}
/* Store the entry. */
this->used[key / 64] |= (uint64_t)1 << (key % 64);
this->values[key] = value;
this->size++;
return 0;
fail:
return 0;
}
/**
* Remove an entry in the table
*
* @param this The fd table
* @param key The key of the entry to remove
* @return The previous value associated with the key, 0 if the key was not used
*/
size_t
fd_table_remove(fd_table_t *restrict this, int key)
{
size_t rc = fd_table_get(this, key);
if (rc && fd_table_contains_key(this, key)) {
this->used[key / 64] &= ~((uint64_t)1 << (key % 64));
this->size--;
}
return rc;
}
/**
* Remove all entries in the table
*
* @param this The fd table
*/
void
fd_table_clear(fd_table_t *restrict this)
{
size_t bitcap;
this->size = 0;
bitcap = (this->capacity + 63) / 64;
memset(this->used, 0, bitcap * sizeof(uint64_t));
}
/**
* Calculate the buffer size need to marshal a fd table
*
* @param this The fd table
* @return The number of bytes to allocate to the output buffer
*/
size_t
fd_table_marshal_size(const fd_table_t *restrict this)
{
size_t bitcap = (this->capacity + 63) / 64;
return (this->capacity + 2) * sizeof(size_t) + bitcap * sizeof(uint64_t) + sizeof(int);
}
/**
* Marshals a fd table
*
* @param this The fd table
* @param data Output buffer for the marshalled data
*/
void
fd_table_marshal(const fd_table_t *restrict this, char *restrict data)
{
size_t bitcap = (this->capacity + 63) / 64;
buf_set_next(data, int, FD_TABLE_T_VERSION);
buf_set_next(data, size_t, this->capacity);
buf_set_next(data, size_t, this->size);
memcpy(data, this->values, this->capacity * sizeof(size_t));
buf_next(data, size_t, this->capacity);
memcpy(data, this->used, bitcap * sizeof(uint64_t));
}
/**
* Unmarshals a fd table
*
* @param this Memory slot in which to store the new fd table
* @param data In buffer with the marshalled data
* @param remapper Function that translates values, `NULL` if not translation takes place
* @return Non-zero on error, `errno` will be set accordingly.
* Destroy the table on error.
*/
int
fd_table_unmarshal(fd_table_t *restrict this, char *restrict data, remap_func *remapper)
{
size_t bitcap;
size_t i;
/* buf_get(data, int, 0, FD_TABLE_T_VERSION) */
buf_next(data, int, 1);
buf_get_next(data, size_t, this->capacity);
buf_get_next(data, size_t, this->size);
this->values = NULL;
this->used = NULL;
this->value_comparator = NULL;
fail_if (xmalloc(this->values, this->capacity, size_t));
bitcap = (this->capacity + 63) / 64;
fail_if (xmalloc(this->used, bitcap, size_t));
memcpy(this->values, data, this->capacity * sizeof(size_t));
buf_next(data, size_t, this->capacity);
memcpy(this->used, data, bitcap * sizeof(uint64_t));
if (remapper)
for (i = 0; i < this->capacity; i++)
if (this->used[i / 64] & ((uint64_t)1 << (i % 64)))
this->values[i] = remapper(this->values[i]);
return 0;
fail:
return -1;
}
