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/*
 * Copyright (c) 2008 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 net
 * @{
 */

/** @file
 */

#include <errno.h>
#include <unistd.h>
#include <string.h>

#include <ipc/ipc.h>
#include <sys/mman.h>

#include "../../err.h"

#include "packet.h"

#define PACKET_MAGIC_VALUE  0x11227788

struct packet{
    size_t  length;
    size_t  max_prefix;
    size_t  max_content;
    size_t  data_start;
    size_t  data_end;
    int magic_value;
};

int packet_is_valid( packet_t packet );

packet_t packet_create( size_t max_prefix, size_t max_content, size_t max_sufix ){
    size_t      length;
    packet_t    packet;

    length = max_prefix + max_content + max_sufix;
    packet = ( packet_t ) mmap( NULL, sizeof( struct packet ) + length, PROTO_READ | PROTO_WRITE, MAP_SHARED | MAP_ANONYMOUS, 0, 0 );
    if( packet == MAP_FAILED ) return NULL;
    packet->length = length;
    packet->max_prefix = max_prefix;
    packet->max_content = max_content;
    packet->data_start = sizeof( struct packet ) + packet->max_prefix;
    packet->data_end = packet->data_start;
    packet->magic_value = PACKET_MAGIC_VALUE;
    return packet;
}

int packet_is_valid( packet_t packet ){
    return packet && ( packet->magic_value == PACKET_MAGIC_VALUE );
}

packet_t packet_copy( packet_t packet ){
    packet_t    new;

    if( ! packet_is_valid( packet )) return NULL;
    new = ( packet_t ) mmap( NULL, packet->length, PROTO_READ | PROTO_WRITE, MAP_SHARED | MAP_ANONYMOUS, 0, 0 );
    if( new == MAP_FAILED ) return NULL;
    memcpy( new, packet, packet->length );
    return new;
}

int packet_copy_data( packet_t packet, void * data, size_t length ){
    if( ! packet_is_valid( packet )) return EINVAL;
    if( packet->data_start + length >= (( size_t ) packet ) + packet->length ) return ENOMEM;
    memcpy( packet + packet->data_start, data, length );
    if( packet->data_start + length > packet->data_end ){
        packet->data_end = packet->data_start + length;
    }
    return EOK;
}

void * packet_prepend( packet_t packet, size_t length ){
    if(( ! packet_is_valid( packet )) || ( packet->data_start - sizeof( struct packet ) < length )) return NULL;
    packet->data_start -= length;
    return packet + packet->data_start;
}

void * packet_append( packet_t packet, size_t length ){
    if(( ! packet_is_valid( packet )) || ( packet->data_end + length >= (( size_t ) packet ) + packet->length )) return NULL;
    packet->data_end += length;
    return packet + packet->data_end - length;
}

int packet_trim( packet_t packet, size_t prefix, size_t sufix ){
    if(( ! packet_is_valid( packet )) || ( prefix + sufix > packet->data_end - packet->data_start )) return EINVAL;
    packet->data_start += prefix;
    packet->data_end -= sufix;
    return EOK;
}

int packet_send( packet_t packet, int phone ){
    if( ! packet_is_valid( packet )) return EINVAL;
    return ipc_share_out_start( phone, packet, PROTO_READ | PROTO_WRITE );
}

int packet_receive( packet_ref packet ){
    ERROR_DECLARE;

    ipc_callid_t    callid;
    size_t      size;
    int     flags;

    if( ! packet ) return EINVAL;
    if( ! ipc_share_out_receive( & callid, & size, & flags )) return EINVAL;
    * packet = ( packet_t ) as_get_mappable_page( size );
    if( !( * packet )) return ENOMEM;
    if( ERROR_OCCURED( ipc_share_out_finalize( callid, * packet ))){
        munmap( * packet, size );
        return ERROR_CODE;
    }
    return EOK;
}

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

size_t packet_get_data_length( packet_t packet ){
    if( ! packet_is_valid( packet )) return 0;
    return packet->data_end - packet->data_start;
}

void * packet_get_data( packet_t packet ){
    if( ! packet_is_valid( packet )) return NULL;
    return packet + packet->data_start;
}

/** @}
 */