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 LIBC_FIFO_H_ 00046 #define LIBC_FIFO_H_ 00047 00048 #include <malloc.h> 00049 00050 typedef unsigned long fifo_count_t; 00051 typedef unsigned long fifo_index_t; 00052 00053 #define FIFO_CREATE_STATIC(name, t, itms) \ 00054 struct { \ 00055 t fifo[(itms)]; \ 00056 fifo_count_t items; \ 00057 fifo_index_t head; \ 00058 fifo_index_t tail; \ 00059 } name 00060 00070 #define FIFO_INITIALIZE_STATIC(name, t, itms) \ 00071 FIFO_CREATE_STATIC(name, t, itms) = { \ 00072 .items = (itms), \ 00073 .head = 0, \ 00074 .tail = 0 \ 00075 } 00076 00086 #define FIFO_INITIALIZE_DYNAMIC(name, t, itms) \ 00087 struct { \ 00088 t *fifo; \ 00089 fifo_count_t items; \ 00090 fifo_index_t head; \ 00091 fifo_index_t tail; \ 00092 } name = { \ 00093 .fifo = NULL, \ 00094 .items = (itms), \ 00095 .head = 0, \ 00096 .tail = 0 \ 00097 } 00098 00105 #define fifo_pop(name) \ 00106 name.fifo[name.head = (name.head + 1) < name.items ? (name.head + 1) : 0] 00107 00114 #define fifo_push(name, value) \ 00115 name.fifo[name.tail = (name.tail + 1) < name.items ? (name.tail + 1) : 0] = (value) 00116 00121 #define fifo_create(name) \ 00122 name.fifo = malloc(sizeof(*name.fifo) * name.items) 00123 00124 #endif 00125