/*
 * Copyright (c) 2009 Lukas Mejdrech
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup packet
 *  @{
 */

/** @file
 *  Packet map and queue implementation.
 *  This file has to be compiled with both the packet server and the client.
 */

#include <errno.h>
#include <malloc.h>
#include <mem.h>
#include <fibril_synch.h>
#include <unistd.h>

#include <sys/mman.h>

#include <net_err.h>
#include <adt/generic_field.h>
#include <packet/packet.h>
#include <packet/packet_header.h>

/** Packet map page size.
 */
#define PACKET_MAP_SIZE	100

/** Returns the packet map page index.
 *  @param[in] packet_id The packet identifier.
 */
#define PACKET_MAP_PAGE(packet_id)	(((packet_id) - 1) / PACKET_MAP_SIZE)

/** Returns the packet index in the corresponding packet map page.
 *  @param[in] packet_id The packet identifier.
 */
#define PACKET_MAP_INDEX(packet_id)	(((packet_id) - 1) % PACKET_MAP_SIZE)

/** Type definition of the packet map page.
 */
typedef packet_t packet_map_t[PACKET_MAP_SIZE];
/** Type definition of the packet map page pointer.
 */
typedef packet_map_t * packet_map_ref;

/** Packet map.
 *  Maps packet identifiers to the packet references.
 *  @see generic_field.h
 */
GENERIC_FIELD_DECLARE(gpm, packet_map_t);

/** Releases the packet.
 *  @param[in] packet The packet to be released.
 *  @returns EOK on success.
 *  @returns EINVAL if the packet is not valid.
 */
int packet_destroy(packet_t packet);

/** Packet map global data.
 */
static struct{
	/** Safety lock.
	 */
	fibril_rwlock_t lock;
	/** Packet map.
	 */
	gpm_t packet_map;
} pm_globals;

GENERIC_FIELD_IMPLEMENT(gpm, packet_map_t);

int packet_destroy(packet_t packet){
	if(! packet_is_valid(packet)){
		return EINVAL;
	}
	return munmap(packet, packet->length);
}

int pm_init(void){
	ERROR_DECLARE;

	fibril_rwlock_initialize(&pm_globals.lock);
	fibril_rwlock_write_lock(&pm_globals.lock);
	ERROR_PROPAGATE(gpm_initialize(&pm_globals.packet_map));
	fibril_rwlock_write_unlock(&pm_globals.lock);
	return EOK;
}

packet_t pm_find(packet_id_t packet_id){
	packet_map_ref map;
	packet_t packet;

	if(! packet_id){
		return NULL;
	}
	fibril_rwlock_read_lock(&pm_globals.lock);
	if(packet_id > PACKET_MAP_SIZE * gpm_count(&pm_globals.packet_map)){
		fibril_rwlock_read_unlock(&pm_globals.lock);
		return NULL;
	}
	map = gpm_get_index(&pm_globals.packet_map, PACKET_MAP_PAGE(packet_id));
	if(! map){
		fibril_rwlock_read_unlock(&pm_globals.lock);
		return NULL;
	}
	packet = (*map)[PACKET_MAP_INDEX(packet_id)];
	fibril_rwlock_read_unlock(&pm_globals.lock);
	return packet;
}

int pm_add(packet_t packet){
	ERROR_DECLARE;

	packet_map_ref map;

	if(! packet_is_valid(packet)){
		return EINVAL;
	}
	fibril_rwlock_write_lock(&pm_globals.lock);
	if(PACKET_MAP_PAGE(packet->packet_id) < gpm_count(&pm_globals.packet_map)){
		map = gpm_get_index(&pm_globals.packet_map, PACKET_MAP_PAGE(packet->packet_id));
	}else{
		do{
			map = (packet_map_ref) malloc(sizeof(packet_map_t));
			if(! map){
				fibril_rwlock_write_unlock(&pm_globals.lock);
				return ENOMEM;
			}
			bzero(map, sizeof(packet_map_t));
			if((ERROR_CODE = gpm_add(&pm_globals.packet_map, map)) < 0){
				fibril_rwlock_write_unlock(&pm_globals.lock);
				free(map);
				return ERROR_CODE;
			}
		}while(PACKET_MAP_PAGE(packet->packet_id) >= gpm_count(&pm_globals.packet_map));
	}
	(*map)[PACKET_MAP_INDEX(packet->packet_id)] = packet;
	fibril_rwlock_write_unlock(&pm_globals.lock);
	return EOK;
}

void pm_destroy(void){
	int count;
	int index;
	packet_map_ref map;
	packet_t packet;

	fibril_rwlock_write_lock(&pm_globals.lock);
	count = gpm_count(&pm_globals.packet_map);
	while(count > 0){
		map = gpm_get_index(&pm_globals.packet_map, count - 1);
		for(index = PACKET_MAP_SIZE - 1; index >= 0; -- index){
			packet = (*map)[index];
			if(packet_is_valid(packet)){
				munmap(packet, packet->length);
			}
		}
	}
	gpm_destroy(&pm_globals.packet_map);
	// leave locked
}

int pq_add(packet_t * first, packet_t packet, size_t order, size_t metric){
	packet_t item;

	if((! first) || (! packet_is_valid(packet))){
		return EINVAL;
	}
	pq_set_order(packet, order, metric);
	if(packet_is_valid(*first)){
		item = * first;
		do{
			if(item->order < order){
				if(item->next){
					item = pm_find(item->next);
				}else{
					item->next = packet->packet_id;
					packet->previous = item->packet_id;
					return EOK;
				}
			}else{
				packet->previous = item->previous;
				packet->next = item->packet_id;
				item->previous = packet->packet_id;
				item = pm_find(packet->previous);
				if(item){
					item->next = packet->packet_id;
				}else{
					*first = packet;
				}
				return EOK;
			}
		}while(packet_is_valid(item));
	}
	*first = packet;
	return EOK;
}

packet_t pq_find(packet_t packet, size_t order){
	packet_t item;

	if(! packet_is_valid(packet)){
		return NULL;
	}
	item = packet;
	do{
		if(item->order == order){
			return item;
		}
		item = pm_find(item->next);
	}while(item && (item != packet) && packet_is_valid(item));
	return NULL;
}

int pq_insert_after(packet_t packet, packet_t new_packet){
	packet_t item;

	if(!(packet_is_valid(packet) && packet_is_valid(new_packet))){
		return EINVAL;
	}
	new_packet->previous = packet->packet_id;
	new_packet->next = packet->next;
	item = pm_find(packet->next);
	if(item){
		item->previous = new_packet->packet_id;
	}
	packet->next = new_packet->packet_id;
	return EOK;
}

packet_t pq_detach(packet_t packet){
	packet_t next;
	packet_t previous;

	if(! packet_is_valid(packet)){
		return NULL;
	}
	next = pm_find(packet->next);
	if(next){
		next->previous = packet->previous;
		previous = pm_find(next->previous);
		if(previous){
			previous->next = next->packet_id;
		}
	}
	packet->previous = 0;
	packet->next = 0;
	return next;
}

int pq_set_order(packet_t packet, size_t order, size_t metric){
	if(! packet_is_valid(packet)){
		return EINVAL;
	}
	packet->order = order;
	packet->metric = metric;
	return EOK;
}

int pq_get_order(packet_t packet, size_t * order, size_t * metric){
	if(! packet_is_valid(packet)){
		return EINVAL;
	}
	if(order){
		*order = packet->order;
	}
	if(metric){
		*metric = packet->metric;
	}
	return EOK;
}

void pq_destroy(packet_t first, void (*packet_release)(packet_t packet)){
	packet_t actual;
	packet_t next;

	actual = first;
	while(packet_is_valid(actual)){
		next = pm_find(actual->next);
		actual->next = 0;
		actual->previous = 0;
		if(packet_release){
			packet_release(actual);
		}
		actual = next;
	}
}

packet_t pq_next(packet_t packet){
	if(! packet_is_valid(packet)){
		return NULL;
	}
	return pm_find(packet->next);
}

packet_t pq_previous(packet_t packet){
	if(! packet_is_valid(packet)){
		return NULL;
	}
	return pm_find(packet->previous);
}

/** @}
 */