Rev 1481 | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
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| 996 | cejka | 1 | /* |
| 2 | * Copyright (C) 2006 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 1653 | cejka | 29 | /** @addtogroup libc |
| 30 | * @{ |
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| 31 | */ |
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| 32 | /** @file |
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| 33 | */ |
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| 34 | |||
| 996 | cejka | 35 | /* |
| 36 | * This implementation of FIFO stores values in an array |
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| 37 | * (static or dynamic). As such, these FIFOs have upper bound |
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| 38 | * on number of values they can store. Push and pop operations |
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| 39 | * are done via accessing the array through head and tail indices. |
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| 40 | * Because of better operation ordering in fifo_pop(), the access |
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| 41 | * policy for these two indices is to 'increment (mod size of FIFO) |
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| 42 | * and use'. |
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| 43 | */ |
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| 44 | |||
| 45 | #ifndef __FIFO_H__ |
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| 46 | #define __FIFO_H__ |
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| 47 | |||
| 48 | #include <malloc.h> |
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| 49 | |||
| 50 | typedef unsigned long fifo_count_t; |
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| 51 | typedef unsigned long fifo_index_t; |
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| 52 | |||
| 1481 | cejka | 53 | #define FIFO_CREATE_STATIC(name, t, itms) \ |
| 54 | struct { \ |
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| 55 | t fifo[(itms)]; \ |
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| 56 | fifo_count_t items; \ |
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| 57 | fifo_index_t head; \ |
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| 58 | fifo_index_t tail; \ |
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| 59 | } name |
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| 60 | |||
| 996 | cejka | 61 | /** Create and initialize static FIFO. |
| 62 | * |
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| 63 | * FIFO is allocated statically. |
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| 64 | * This macro is suitable for creating smaller FIFOs. |
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| 65 | * |
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| 66 | * @param name Name of FIFO. |
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| 67 | * @param t Type of values stored in FIFO. |
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| 68 | * @param itms Number of items that can be stored in FIFO. |
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| 69 | */ |
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| 70 | #define FIFO_INITIALIZE_STATIC(name, t, itms) \ |
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| 1481 | cejka | 71 | FIFO_CREATE_STATIC(name, t, itms) = { \ |
| 996 | cejka | 72 | .items = (itms), \ |
| 73 | .head = 0, \ |
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| 74 | .tail = 0 \ |
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| 75 | } |
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| 76 | |||
| 77 | /** Create and prepare dynamic FIFO. |
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| 78 | * |
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| 79 | * FIFO is allocated dynamically. |
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| 80 | * This macro is suitable for creating larger FIFOs. |
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| 81 | * |
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| 82 | * @param name Name of FIFO. |
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| 83 | * @param t Type of values stored in FIFO. |
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| 84 | * @param itms Number of items that can be stored in FIFO. |
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| 85 | */ |
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| 86 | #define FIFO_INITIALIZE_DYNAMIC(name, t, itms) \ |
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| 87 | struct { \ |
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| 88 | t *fifo; \ |
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| 89 | fifo_count_t items; \ |
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| 90 | fifo_index_t head; \ |
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| 91 | fifo_index_t tail; \ |
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| 92 | } name = { \ |
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| 93 | .fifo = NULL, \ |
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| 94 | .items = (itms), \ |
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| 95 | .head = 0, \ |
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| 96 | .tail = 0 \ |
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| 97 | } |
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| 98 | |||
| 99 | /** Pop value from head of FIFO. |
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| 100 | * |
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| 101 | * @param name FIFO name. |
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| 102 | * |
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| 103 | * @return Leading value in FIFO. |
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| 104 | */ |
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| 105 | #define fifo_pop(name) \ |
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| 106 | name.fifo[name.head = (name.head + 1) < name.items ? (name.head + 1) : 0] |
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| 107 | |||
| 108 | /** Push value to tail of FIFO. |
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| 109 | * |
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| 110 | * @param name FIFO name. |
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| 111 | * @param value Value to be appended to FIFO. |
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| 112 | * |
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| 113 | */ |
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| 114 | #define fifo_push(name, value) \ |
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| 115 | name.fifo[name.tail = (name.tail + 1) < name.items ? (name.tail + 1) : 0] = (value) |
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| 116 | |||
| 117 | /** Allocate memory for dynamic FIFO. |
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| 118 | * |
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| 119 | * @param name FIFO name. |
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| 120 | */ |
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| 121 | #define fifo_create(name) \ |
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| 122 | name.fifo = malloc(sizeof(*name.fifo) * name.items) |
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| 123 | |||
| 124 | #endif |
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| 1653 | cejka | 125 | |
| 126 | |||
| 127 | /** @} |
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| 128 | */ |
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| 129 | |||
| 130 |