/*
* 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 net
* @{
*/
/** @file
* Dynamic first in first out positive integer queue implementation.
*/
#include <errno.h>
#include <malloc.h>
#include <mem.h>
#include "dynamic_fifo.h"
/** Internal magic value for a consistency check.
*/
#define DYN_FIFO_MAGIC_VALUE 0x58627659
/** Returns the next queue index.
* The queue field is circular.
* @param[in] fifo The dynamic queue.
* @param[in] index The actual index to be shifted.
*/
#define NEXT_INDEX( fifo, index ) ((( index ) + 1 ) % (( fifo )->size + 1 ))
/** Checks if the queue is valid.
* @param[in] fifo The dynamic queue.
* @returns TRUE if the queue is valid.
* @returns FALSE otherwise.
*/
int dyn_fifo_is_valid( dyn_fifo_ref fifo );
int dyn_fifo_is_valid( dyn_fifo_ref fifo ){
return fifo && ( fifo->magic_value == DYN_FIFO_MAGIC_VALUE );
}
int dyn_fifo_initialize( dyn_fifo_ref fifo, int size ){
if( ! fifo ) return EBADMEM;
if( size <= 0 ) return EINVAL;
fifo
->items
= ( int * ) malloc( sizeof( int ) * size
+ 1 ); if( ! fifo->items ) return ENOMEM;
fifo->size = size;
fifo->head = 0;
fifo->tail = 0;
fifo->magic_value = DYN_FIFO_MAGIC_VALUE;
return EOK;
}
int dyn_fifo_push( dyn_fifo_ref fifo, int value, int max_size ){
int * new_items;
if( ! dyn_fifo_is_valid( fifo )) return EINVAL;
if( NEXT_INDEX( fifo, fifo->tail ) == fifo->head ){
if(( max_size > 0 ) && (( fifo->size * 2 ) > max_size )){
if( fifo->size >= max_size ) return ENOMEM;
}else{
max_size = fifo->size * 2;
}
new_items
= realloc( fifo
->items
, sizeof( int ) * max_size
+ 1 ); if( ! new_items ) return ENOMEM;
fifo->items = new_items;
if( fifo->tail < fifo->head ){
if( fifo->tail < max_size - fifo->size ){
memcpy( fifo
->items
+ fifo
->size
+ 1, fifo
->items
, fifo
->tail
* sizeof( int )); fifo->tail += fifo->size + 1;
}else{
memcpy( fifo
->items
+ fifo
->size
+ 1, fifo
->items
, ( max_size
- fifo
->size
) * sizeof( int )); memcpy( fifo
->items
, fifo
->items
+ max_size
- fifo
->size
, fifo
->tail
- max_size
+ fifo
->size
); fifo->tail -= max_size - fifo->size;
}
}
fifo->size = max_size;
}
fifo->items[ fifo->tail ] = value;
fifo->tail = NEXT_INDEX( fifo, fifo->tail );
return EOK;
}
int dyn_fifo_pop( dyn_fifo_ref fifo ){
int value;
if( ! dyn_fifo_is_valid( fifo )) return EINVAL;
if( fifo->head == fifo->tail ) return ENOENT;
value = fifo->items[ fifo->head ];
fifo->head = NEXT_INDEX( fifo, fifo->head );
return value;
}
int dyn_fifo_value( dyn_fifo_ref fifo ){
if( ! dyn_fifo_is_valid( fifo )) return EINVAL;
if( fifo->head == fifo->tail ) return ENOENT;
return fifo->items[ fifo->head ];
}
int dyn_fifo_destroy( dyn_fifo_ref fifo ){
if( ! dyn_fifo_is_valid( fifo )) return EINVAL;
fifo->magic_value = 0;
return EOK;
}
/** @}
*/