/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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/>.
*/
#ifndef MDS_LIBMDSSERVER_FD_TABLE_H
#define MDS_LIBMDSSERVER_FD_TABLE_H
#include "table-common.h"
#include <stdint.h>
/**
* Value lookup table optimised for file descriptors as keys
*/
typedef struct fd_table
{
/**
* The table's capacity, i.e. how many entries that can be stored,
* in total, before its internal table needs to grow
*/
size_t capacity;
/**
* The number of entries stored in the table
*/
size_t size;
/**
* Map from keys to values
*/
size_t* values;
/**
* Map from keys to whether that are in used, bit-packed
*/
uint64_t* used;
/**
* Check whether two values are equal
*
* If this function pointer is `NULL`, the identity is used
*
* Be aware, this variable cannot be marshalled
*/
compare_func* value_comparator;
} fd_table_t;
/**
* 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);
/**
* Create a fd table
*
* @param this:fd_table_t* Memory slot in which to store the new fd table
* @return :int Non-zero on error, `errno` will have been set accordingly
*/
#define fd_table_create(this) \
fd_table_create_tuned(this, 16)
/**
* 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);
/**
* 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) __attribute__((pure));
/**
* 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) __attribute__((pure));
/**
* 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) __attribute__((pure));
/**
* 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);
/**
* 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);
/**
* Remove all entries in the table
*
* @param this The fd table
*/
void fd_table_clear(fd_table_t* restrict this);
/**
* 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) __attribute__((pure));
/**
* 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);
/**
* 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);
#endif
