00001 /* 00002 * Copyright (C) 2006 Jakub Jermar 00003 * All rights reserved. 00004 * 00005 * Redistribution and use in source and binary forms, with or without 00006 * modification, are permitted provided that the following conditions 00007 * are met: 00008 * 00009 * - Redistributions of source code must retain the above copyright 00010 * notice, this list of conditions and the following disclaimer. 00011 * - Redistributions in binary form must reproduce the above copyright 00012 * notice, this list of conditions and the following disclaimer in the 00013 * documentation and/or other materials provided with the distribution. 00014 * - The name of the author may not be used to endorse or promote products 00015 * derived from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 00018 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00019 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 00020 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 00021 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 00022 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00023 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00024 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00025 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 00026 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00027 */ 00028 00035 /* 00036 * This implementation of FIFO stores values in an array 00037 * (static or dynamic). As such, these FIFOs have upper bound 00038 * on number of values they can store. Push and pop operations 00039 * are done via accessing the array through head and tail indices. 00040 * Because of better operation ordering in fifo_pop(), the access 00041 * policy for these two indices is to 'increment (mod size of FIFO) 00042 * and use'. 00043 */ 00044 00045 #ifndef __FIFO_H__ 00046 #define __FIFO_H__ 00047 00048 #include <typedefs.h> 00049 #include <mm/slab.h> 00050 00060 #define FIFO_INITIALIZE_STATIC(name, t, itms) \ 00061 struct { \ 00062 t fifo[(itms)]; \ 00063 count_t items; \ 00064 index_t head; \ 00065 index_t tail; \ 00066 } name = { \ 00067 .items = (itms), \ 00068 .head = 0, \ 00069 .tail = 0 \ 00070 } 00071 00081 #define FIFO_INITIALIZE_DYNAMIC(name, t, itms) \ 00082 struct { \ 00083 t *fifo; \ 00084 count_t items; \ 00085 index_t head; \ 00086 index_t tail; \ 00087 } name = { \ 00088 .fifo = NULL, \ 00089 .items = (itms), \ 00090 .head = 0, \ 00091 .tail = 0 \ 00092 } 00093 00100 #define fifo_pop(name) \ 00101 name.fifo[name.head = (name.head + 1) < name.items ? (name.head + 1) : 0] 00102 00109 #define fifo_push(name, value) \ 00110 name.fifo[name.tail = (name.tail + 1) < name.items ? (name.tail + 1) : 0] = (value) 00111 00116 #define fifo_create(name) \ 00117 name.fifo = malloc(sizeof(*name.fifo) * name.items, 0) 00118 00119 #endif 00120