[5284] | 1 | /// ----------------------------------------*- mode: C++; -*--
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| 2 | /// @file fastqueue.c
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| 3 | /// a simple FIFO queue with mutexes for use with pthreads
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| 4 | /// ----------------------------------------------------------
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| 5 | /// $Id: fastqueue.c 2549 2007-04-02 22:17:37Z bless $
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| 6 | /// $HeadURL: https://svn.ipv6.tm.uka.de/nsis/protlib/trunk/fastqueue/fastqueue.c $
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| 7 | // ===========================================================
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| 8 | //
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| 9 | // Copyright (C) 2005-2007, all rights reserved by
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| 10 | // - Institute of Telematics, Universitaet Karlsruhe (TH)
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| 11 | //
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| 12 | // More information and contact:
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| 13 | // https://projekte.tm.uka.de/trac/NSIS
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| 14 | //
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| 15 | // This program is free software; you can redistribute it and/or modify
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| 16 | // it under the terms of the GNU General Public License as published by
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| 17 | // the Free Software Foundation; version 2 of the License
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| 18 | //
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| 19 | // This program is distributed in the hope that it will be useful,
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| 20 | // but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 21 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 22 | // GNU General Public License for more details.
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| 23 | //
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| 24 | // You should have received a copy of the GNU General Public License along
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| 25 | // with this program; if not, write to the Free Software Foundation, Inc.,
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| 26 | // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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| 27 | //
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| 28 | // ===========================================================
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| 29 |
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[9686] | 30 | /** @addtogroup protlib
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[5284] | 31 | * @{
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| 32 | */
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| 33 |
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| 34 | /** @file
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| 35 | * Fast and thread-safe queue.
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| 36 | */
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| 37 |
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| 38 | /******************************************************************************
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| 39 | * fastqueue.c -- a simple FIFO queue with mutexes for use with pthreads *
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| 40 | * -------------------------------------------------------------------------- *
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| 41 | * written by Roland Bless 1995 *
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| 42 | * all operations enqueue,dequeue are done in O(1) which means constant time *
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| 43 | ******************************************************************************/
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| 44 |
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| 45 | #define _GNU_SOURCE
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| 46 | #include <stdio.h>
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| 47 | #include <string.h>
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| 48 | #include <pthread.h>
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| 49 | #include <stdlib.h>
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| 50 | #include <errno.h>
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| 51 | #include <sys/time.h>
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| 52 | #include <unistd.h>
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| 53 |
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| 54 | /**** module interface ****/
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| 55 | #include "fastqueue.h"
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| 56 |
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| 57 | /*************** defines *****************/
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| 58 | #define qerr(errnr) fprintf(stderr,"queue.c: %s\n",queue_errmsg[errnr])
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| 59 |
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| 60 |
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| 61 | #define PTHREAD_MUTEX_NORMAL PTHREAD_MUTEX_TIMED_NP
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| 62 | #define PRI_OTHER_MIN PRI_FG_MIN_NP
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| 63 | #define PRI_OTHER_MAX PRI_FG_MAX_NP
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| 64 | #define PRI_FG_MIN_NP 8
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| 65 | #define PRI_FG_MAX_NP 15
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| 66 |
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| 67 | #define CLOCK_REALTIME 0
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| 68 | #define NSEC_PER_SEC 1000000000
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| 69 | extern int eclock_gettime(struct timespec *tp);
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| 70 | #define clock_gettime(clock_id, tspec) eclock_gettime(tspec)
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| 71 |
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| 72 | /*************** typedefs *****************/
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| 73 |
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| 74 | enum {
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| 75 | QERR_NONE,
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| 76 | QERR_NOMEM,
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| 77 | QERR_MUTEXINIT,
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| 78 | QERR_MUTEXLOCK,
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| 79 | QERR_MUTEXUNLOCK,
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| 80 | QERR_MUTEXDESTROY,
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| 81 | QERR_QEMPTY,
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| 82 | QERR_QINVALID,
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| 83 | QERR_QNOTEMPTY,
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| 84 | QERR_CONDINIT,
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| 85 | QERR_CONDWAIT,
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| 86 | QERR_CONDSIGNAL,
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| 87 | QERR_CONDDESTROY
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| 88 | };
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| 89 |
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| 90 | const
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| 91 | char *const queue_errmsg[]=
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| 92 | {
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| 93 | "all ok",
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| 94 | "can't get enough memory",
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| 95 | "initializing mutex",
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| 96 | "locking mutex",
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| 97 | "unlocking mutex",
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| 98 | "destroying mutex",
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| 99 | "queue empty",
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| 100 | "invalid queueobject",
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| 101 | "destroying queue - queue not empty",
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| 102 | "initializing queue condition variable",
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| 103 | "waiting on condition",
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| 104 | "signalling condition",
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| 105 | "destroying condition"
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| 106 | };
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| 107 |
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| 108 |
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| 109 |
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| 110 | queue_t *create_queue(const char* name)
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| 111 | /* initialization routine for a queue.
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| 112 | * returns: NULL if an error occured, or a queue-object which is actually
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| 113 | * a queueheader structure
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| 114 | * arguments: none
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| 115 | */
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| 116 | {
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| 117 | queue_t *queuehead;
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| 118 |
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| 119 | /* Allocate memory for queue head */
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| 120 | if ((queuehead= (queue_t *) malloc(sizeof(queue_t)))!=NULL)
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| 121 | {
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| 122 | /* Set mutex kind */
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| 123 | pthread_mutexattr_init(&queuehead->mutex_attr);
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| 124 | #ifdef _DEBUG
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| 125 | pthread_mutexattr_settype(&queuehead->mutex_attr,PTHREAD_MUTEX_ERRORCHECK);
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| 126 | #else
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| 127 | pthread_mutexattr_settype(&queuehead->mutex_attr,PTHREAD_MUTEX_NORMAL);
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| 128 | #endif
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| 129 | /* use PTHREAD_MUTEX_ERRORCHECK or PTHREAD_MUTEX_ERRORCHECK_NP for testing */
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| 130 |
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| 131 | /* Initialize mutex */
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| 132 | if (pthread_mutex_init(&queuehead->mutex, &queuehead->mutex_attr)==0)
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| 133 | {
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| 134 | /* Create Condition variable for command queue */
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| 135 | if (pthread_cond_init(&queuehead->cond, NULL)==0)
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| 136 | {
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| 137 | queuehead->nr_of_elements= 0UL;
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| 138 | queuehead->exp_nr_of_elements= 0UL;
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| 139 | queuehead->exp_enabled = 0;
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| 140 | queuehead->first_block= (queue_elblock_t *) malloc(sizeof(queue_elblock_t));
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| 141 | queuehead->exp_first_block= (queue_elblock_t *) malloc(sizeof(queue_elblock_t));
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| 142 | if ((queuehead->first_block == NULL) || (queuehead->exp_first_block == NULL))
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| 143 | qerr(QERR_NOMEM);
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| 144 | else
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| 145 | {
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| 146 | queuehead->first_block->read= 0;
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| 147 | queuehead->first_block->write= 0;
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| 148 | queuehead->first_block->next_block= NULL;
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| 149 | queuehead->last_block= queuehead->first_block;
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| 150 | queuehead->exp_first_block->read= 0;
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| 151 | queuehead->exp_first_block->write= 0;
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| 152 | queuehead->exp_first_block->next_block= NULL;
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| 153 | queuehead->exp_last_block= queuehead->exp_first_block;
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| 154 | if (name)
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| 155 | {
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| 156 | if (strlen(name) <= MAX_QUEUENAME_LENGTH)
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| 157 | strcpy(queuehead->name, name);
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| 158 | else
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| 159 | {
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| 160 | memcpy(queuehead->name, name, MAX_QUEUENAME_LENGTH);
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| 161 | queuehead->name[MAX_QUEUENAME_LENGTH + 1] = '\0';
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| 162 | }
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| 163 | }
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| 164 | else
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| 165 | queuehead->name[0] = '\0';
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| 166 | /* Now it's simple to enqueue elements, esp. the first one */
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| 167 | }
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| 168 | //#ifdef QUEUELEN
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| 169 | queuehead->queue_maxlength= 0;
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| 170 | //#endif
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| 171 | }
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| 172 | else
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| 173 | qerr(QERR_CONDINIT);
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| 174 | }
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| 175 | else /* error during initialize */
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| 176 | qerr(QERR_MUTEXINIT);
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| 177 | }
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| 178 | else
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| 179 | qerr(QERR_NOMEM);
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| 180 |
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| 181 | return queuehead;
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| 182 | }
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| 183 |
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| 184 | int enqueue_element_signal(queue_t *queuehead, void *element)
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| 185 | {
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| 186 | return enqueue_element_expedited_signal(queuehead,element,0);
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| 187 | }
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| 188 |
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| 189 | int enqueue_element_expedited_signal(queue_t *queuehead, void *element, int exp)
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| 190 | /* add a new element into the queue. Memory for the element must be
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| 191 | * allocated anywhere else. This routine signals other waiting threads.
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| 192 | * returns: -1 if an error occured, or 0 is action could be performed
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| 193 | * arguments: pointer to queue_t object, pointer to an element
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| 194 | */
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| 195 | {
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| 196 | queue_elblock_t *newelement, *lastblockp;
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| 197 |
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| 198 | if (queuehead==NULL)
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| 199 | {
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| 200 | qerr(QERR_QINVALID);
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| 201 | return -1;
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| 202 | }
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| 203 |
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| 204 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
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| 205 | {
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| 206 | qerr(QERR_MUTEXLOCK);
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| 207 | return -1;
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| 208 | }
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| 209 | /* begin critical section */
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| 210 |
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| 211 | if (exp && queuehead->exp_enabled) exp = 1; else exp = 0;
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| 212 | /* Allocate new element structure when necessary */
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| 213 | /* Note: queuehead->last_block must always contain a valid value */
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| 214 | lastblockp = (exp ? (queuehead->exp_last_block) : (queuehead->last_block));
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| 215 | if (lastblockp->write == ELEMENT_BLOCKSIZE)
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| 216 | { /* last block is full, so allocate a new block */
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| 217 | if ((newelement= (queue_elblock_t *) malloc(sizeof(queue_elblock_t)))==NULL)
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| 218 | {
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| 219 | qerr(QERR_NOMEM);
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| 220 | return -1;
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| 221 | }
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| 222 |
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| 223 | /* initialize new structure */
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| 224 | newelement->element[0]= element;
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| 225 | newelement->read = 0;
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| 226 | newelement->write = 1;
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| 227 | newelement->next_block= NULL;
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| 228 |
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| 229 | /* append new element to the end */
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| 230 | lastblockp->next_block= newelement;
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| 231 | /* new element becomes last element */
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| 232 | if (exp) queuehead->exp_last_block = newelement;
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| 233 | else queuehead->last_block = newelement;
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| 234 | }
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| 235 | else /* last block was not full */
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| 236 | {
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| 237 | lastblockp->element[lastblockp->write]= element;
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| 238 | lastblockp->write++;
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| 239 | }
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| 240 |
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| 241 | if (exp) queuehead->exp_nr_of_elements++;
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| 242 | queuehead->nr_of_elements++;
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| 243 | //#ifdef QUEUELEN
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| 244 | if (queuehead->nr_of_elements > queuehead->queue_maxlength)
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| 245 | queuehead->queue_maxlength= queuehead->nr_of_elements;
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| 246 | //#endif
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| 247 | /* Condition should be set while mutex is locked.
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| 248 | Recommended by libc manual.
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| 249 | */
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| 250 | if (pthread_cond_signal(&queuehead->cond)!=0)
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| 251 | qerr(QERR_CONDSIGNAL);
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| 252 | /* end critical section */
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| 253 | if (pthread_mutex_unlock(&queuehead->mutex)!=0)
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| 254 | {
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| 255 | qerr(QERR_MUTEXUNLOCK);
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| 256 | return -1;
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| 257 | }
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| 258 | // see above
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| 259 | // if (pthread_cond_signal(&queuehead->cond)!=0)
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| 260 | // qerr(QERR_CONDSIGNAL);
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| 261 |
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| 262 | return 0;
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| 263 | }
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| 264 |
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| 265 |
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| 266 | void *dequeue_element_wait(queue_t *queuehead)
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| 267 | /* wait for the queue to contain an element.
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| 268 | * if it contains an element return and remove it.
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| 269 | * returns: NULL if an error occured, the pointer to the element otherwise
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| 270 | * arguments: pointer to queue_t object
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| 271 | */
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| 272 | {
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| 273 | void *element;
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| 274 | queue_elblock_t *blockp;
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| 275 | int exp = 0;
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| 276 | element= NULL;
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| 277 | int retcode= 0;
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| 278 |
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| 279 | if (queuehead != NULL)
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| 280 | {
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| 281 | /* Wait for an element in the queue */
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| 282 | /* Before waiting on a condition, the associated mutex must be locked */
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| 283 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
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| 284 | {
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| 285 | qerr(QERR_MUTEXLOCK); return NULL;
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| 286 | }
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| 287 |
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| 288 | while(queuehead->nr_of_elements==0) /* while there is no work to do, wait */
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| 289 | { /* for a safe state the predicate must be checked in a loop! */
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| 290 | /* cond_wait() unlocks the mutex and might return sometimes without
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| 291 | getting a signal! */
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| 292 | if ((retcode= pthread_cond_wait(&queuehead->cond, &queuehead->mutex)) != 0)
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| 293 | {
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| 294 | if (retcode!=EINTR && retcode!=ETIMEDOUT)
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| 295 | {
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| 296 | qerr(QERR_CONDWAIT);
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| 297 | }
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| 298 | }
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| 299 | }
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| 300 |
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| 301 | /* begin critical section */
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| 302 | exp = (queuehead->exp_nr_of_elements!=0);
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| 303 | blockp = (exp ? (queuehead->exp_first_block) : (queuehead->first_block));
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| 304 | if (blockp != NULL)
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| 305 | {
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| 306 | /* get the first element */
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| 307 | element= blockp->element[blockp->read];
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| 308 | blockp->read++;
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| 309 |
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| 310 | if (blockp->next_block == NULL) /* this is the last block */
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| 311 | {
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| 312 | if (blockp->read == blockp->write)
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| 313 | { /* block is completely dequeued, so reset values */
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| 314 | /* the last block always remains allocated! */
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| 315 | blockp->read= 0;
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| 316 | blockp->write= 0;
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| 317 | }
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| 318 | }
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| 319 | else /* this is not the last block */
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| 320 | {
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| 321 | /* if block was completely dequeued, remove it */
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| 322 | if (blockp->read == ELEMENT_BLOCKSIZE)
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| 323 | {
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| 324 | if (exp) queuehead->exp_first_block= blockp->next_block;
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| 325 | else queuehead->first_block= blockp->next_block;
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| 326 | free(blockp);
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| 327 | }
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| 328 | }
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| 329 | if (exp) queuehead->exp_nr_of_elements--;
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| 330 | queuehead->nr_of_elements--;
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| 331 | }
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| 332 | else
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| 333 | qerr(QERR_QEMPTY);
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| 334 |
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| 335 | /* end critical section */
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| 336 | if (pthread_mutex_unlock(&queuehead->mutex)!=0)
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| 337 | {
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| 338 | qerr(QERR_MUTEXUNLOCK);
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| 339 | return NULL;
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| 340 | }
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| 341 | }
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| 342 | else
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| 343 | qerr(QERR_QINVALID);
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| 344 |
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| 345 | return element;
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| 346 | }
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| 347 |
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| 348 | void *dequeue_element_timedwait(queue_t *queuehead, const struct timespec *tspec)
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| 349 | /* wait for the queue to contain an element.
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| 350 | * if it contains an element return and remove it.
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| 351 | * returns: NULL if an error occured, the pointer to the element otherwise
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| 352 | * arguments: pointer to queue_t object
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| 353 | * tpsec is the time interval to wait (not an absolute time!)
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| 354 | */
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| 355 | {
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| 356 | void *element;
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| 357 | queue_elblock_t *blockp;
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| 358 | int result;
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| 359 | struct timespec abs_tspec;
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| 360 | int exp = 0;
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| 361 | element= NULL;
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| 362 |
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| 363 | if (queuehead != NULL)
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| 364 | {
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| 365 | /* Wait for an element in the queue */
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| 366 | /* Before waiting on a condition, the associated mutex must be locked */
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| 367 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
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| 368 | {
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| 369 | qerr(QERR_MUTEXLOCK); return NULL;
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| 370 | }
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| 371 |
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| 372 | while(queuehead->nr_of_elements==0) /* while there is no work to do, wait */
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| 373 | { /* for a safe state the predicate must be checked in a loop! */
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| 374 | /* cond_wait() unlocks the mutex and might return sometimes without
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| 375 | getting a signal! */
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| 376 | clock_gettime(CLOCK_REALTIME, &abs_tspec);
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| 377 | abs_tspec.tv_nsec+= tspec->tv_nsec;
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| 378 | abs_tspec.tv_sec+= tspec->tv_sec;
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| 379 | if (abs_tspec.tv_nsec >= NSEC_PER_SEC)
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| 380 | {
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| 381 | abs_tspec.tv_nsec%= NSEC_PER_SEC;
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| 382 | abs_tspec.tv_sec++;
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| 383 | };
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| 384 |
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| 385 | if ((result = pthread_cond_timedwait(&queuehead->cond,
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| 386 | &queuehead->mutex, &abs_tspec))!=0)
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| 387 | {
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| 388 | if ( (result != ETIMEDOUT) && (result != EINTR) && (result != EINVAL) )
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| 389 | {
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| 390 | qerr(QERR_CONDWAIT);
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| 391 | }
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| 392 | else
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| 393 | { /* timeout */
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| 394 | if (pthread_mutex_unlock(&queuehead->mutex)!=0)
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| 395 | {
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| 396 | qerr(QERR_MUTEXUNLOCK);
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| 397 | return NULL;
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| 398 | }
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| 399 | return NULL;
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| 400 | }
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| 401 | }
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| 402 | }
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| 403 |
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| 404 | /* begin critical section */
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| 405 | exp = (queuehead->exp_nr_of_elements!=0);
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| 406 | blockp = (exp ? (queuehead->exp_first_block) : (queuehead->first_block));
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| 407 | if (blockp != NULL)
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| 408 | {
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| 409 | /* get the first element */
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| 410 | element= blockp->element[blockp->read];
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| 411 | blockp->read++;
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| 412 |
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| 413 | if (blockp->next_block == NULL) /* this is the last block */
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| 414 | {
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| 415 | if (blockp->read == blockp->write)
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| 416 | { /* block is completely dequeued, so reset values */
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| 417 | /* the last block always remains allocated! */
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| 418 | blockp->read= 0;
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| 419 | blockp->write= 0;
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| 420 | }
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| 421 | }
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| 422 | else /* this is not the last block */
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| 423 | {
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| 424 | /* if block was completely dequeued, remove it */
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| 425 | if (blockp->read == ELEMENT_BLOCKSIZE)
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| 426 | {
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| 427 | if (exp) queuehead->exp_first_block= blockp->next_block;
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| 428 | else queuehead->first_block= blockp->next_block;
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| 429 | free(blockp);
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| 430 | }
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| 431 | }
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| 432 | if (exp) queuehead->exp_nr_of_elements--;
|
---|
| 433 | queuehead->nr_of_elements--;
|
---|
| 434 | }
|
---|
| 435 | else
|
---|
| 436 | qerr(QERR_QEMPTY);
|
---|
| 437 |
|
---|
| 438 | /* end critical section */
|
---|
| 439 | if (pthread_mutex_unlock(&queuehead->mutex)!=0)
|
---|
| 440 | {
|
---|
| 441 | qerr(QERR_MUTEXUNLOCK);
|
---|
| 442 | return NULL;
|
---|
| 443 | }
|
---|
| 444 | }
|
---|
| 445 | else
|
---|
| 446 | qerr(QERR_QINVALID);
|
---|
| 447 |
|
---|
| 448 | return element;
|
---|
| 449 | }
|
---|
| 450 |
|
---|
| 451 | int destroy_queue(queue_t *queuehead)
|
---|
| 452 | /* destroys the queue and frees all resources, except the elements!
|
---|
| 453 | * the queue must be empty to destroy it.
|
---|
| 454 | * returns: -1 if an error occured, 0 otherwise
|
---|
| 455 | * arguments: pointer to queue_t object
|
---|
| 456 | */
|
---|
| 457 | {
|
---|
| 458 | if (queuehead!=NULL)
|
---|
| 459 | {
|
---|
| 460 | /* queue not empty? */
|
---|
| 461 | if (queuehead->nr_of_elements != 0)
|
---|
| 462 | qerr(QERR_QNOTEMPTY);
|
---|
| 463 | else
|
---|
| 464 | {
|
---|
| 465 | /* destroy condition variable */
|
---|
| 466 | if (pthread_cond_destroy(&queuehead->cond)!=0) qerr(QERR_CONDDESTROY);
|
---|
| 467 | /* destroy mutex */
|
---|
| 468 | if (pthread_mutex_destroy(&queuehead->mutex)!=0) qerr(QERR_MUTEXDESTROY);
|
---|
| 469 |
|
---|
| 470 | pthread_mutexattr_destroy(&queuehead->mutex_attr);
|
---|
| 471 |
|
---|
| 472 | /* free memory for queuehead */
|
---|
| 473 | #ifdef QUEUELEN
|
---|
| 474 | fprintf(stderr,"queue.c: length of queue (%s) growed up to %lu elements\n",
|
---|
| 475 | queuehead->name, queuehead->queue_maxlength);
|
---|
| 476 | #endif
|
---|
| 477 | free(queuehead->exp_last_block);
|
---|
| 478 | free(queuehead->last_block);
|
---|
| 479 | free(queuehead);
|
---|
| 480 | }
|
---|
| 481 |
|
---|
| 482 | return 0;
|
---|
| 483 | }
|
---|
| 484 | else
|
---|
| 485 | qerr(QERR_QINVALID);
|
---|
| 486 |
|
---|
| 487 | return -1;
|
---|
| 488 | }
|
---|
| 489 |
|
---|
| 490 | void *dequeue_element_nonblocking(queue_t *queuehead)
|
---|
| 491 | /* if queue contains an element return and remove it.
|
---|
| 492 | * returns: NULL if an error occured or queue was empty, the pointer to
|
---|
| 493 | * the element otherwise.
|
---|
| 494 | * arguments: pointer to queue_t object
|
---|
| 495 | */
|
---|
| 496 | {
|
---|
| 497 | void *element;
|
---|
| 498 | queue_elblock_t *blockp;
|
---|
| 499 | int exp = 0;
|
---|
| 500 | element= NULL;
|
---|
| 501 |
|
---|
| 502 | if (queuehead != NULL)
|
---|
| 503 | {
|
---|
| 504 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
|
---|
| 505 | {
|
---|
| 506 | qerr(QERR_MUTEXLOCK); return NULL;
|
---|
| 507 | }
|
---|
| 508 |
|
---|
| 509 | /* begin critical section */
|
---|
| 510 |
|
---|
| 511 | if (queuehead->nr_of_elements==0)
|
---|
| 512 | {
|
---|
| 513 | if (pthread_mutex_unlock(&queuehead->mutex)!=0) qerr(QERR_MUTEXUNLOCK);
|
---|
| 514 | return NULL;
|
---|
| 515 | }
|
---|
| 516 |
|
---|
| 517 | exp = (queuehead->exp_nr_of_elements!=0);
|
---|
| 518 | blockp = (exp ? (queuehead->exp_first_block) : (queuehead->first_block));
|
---|
| 519 | if (blockp != NULL)
|
---|
| 520 | {
|
---|
| 521 | /* get the first element */
|
---|
| 522 | element= blockp->element[blockp->read];
|
---|
| 523 | blockp->read++;
|
---|
| 524 |
|
---|
| 525 | if (blockp->next_block == NULL) /* this is the last block */
|
---|
| 526 | {
|
---|
| 527 | if (blockp->read == blockp->write)
|
---|
| 528 | { /* block is completely dequeued, so reset values */
|
---|
| 529 | /* the last block always remains allocated! */
|
---|
| 530 | blockp->read= 0;
|
---|
| 531 | blockp->write= 0;
|
---|
| 532 | }
|
---|
| 533 | }
|
---|
| 534 | else /* this is not the last block */
|
---|
| 535 | {
|
---|
| 536 | /* if block was completely dequeued, remove it */
|
---|
| 537 | if (blockp->read == ELEMENT_BLOCKSIZE)
|
---|
| 538 | {
|
---|
| 539 | if (exp) queuehead->exp_first_block= blockp->next_block;
|
---|
| 540 | else queuehead->first_block= blockp->next_block;
|
---|
| 541 | free(blockp);
|
---|
| 542 | }
|
---|
| 543 | }
|
---|
| 544 | if (exp) queuehead->exp_nr_of_elements--;
|
---|
| 545 | queuehead->nr_of_elements--;
|
---|
| 546 | }
|
---|
| 547 | else
|
---|
| 548 | qerr(QERR_QEMPTY);
|
---|
| 549 |
|
---|
| 550 | /* end critical section */
|
---|
| 551 | if (pthread_mutex_unlock(&queuehead->mutex)!=0)
|
---|
| 552 | {
|
---|
| 553 | qerr(QERR_MUTEXUNLOCK);
|
---|
| 554 | return NULL;
|
---|
| 555 | }
|
---|
| 556 | }
|
---|
| 557 | else
|
---|
| 558 | qerr(QERR_QINVALID);
|
---|
| 559 |
|
---|
| 560 | return element;
|
---|
| 561 | }
|
---|
| 562 |
|
---|
| 563 | unsigned long queue_nr_of_elements(queue_t *queuehead)
|
---|
| 564 | /** Get number fo elements in queue. */
|
---|
| 565 | {
|
---|
| 566 | unsigned long result = 0;
|
---|
| 567 |
|
---|
| 568 | if (queuehead != NULL)
|
---|
| 569 | {
|
---|
| 570 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
|
---|
| 571 | {
|
---|
| 572 | qerr(QERR_MUTEXLOCK);
|
---|
| 573 | return 0;
|
---|
| 574 | }
|
---|
| 575 | /* begin critical section */
|
---|
| 576 |
|
---|
| 577 | result = queuehead->nr_of_elements;
|
---|
| 578 |
|
---|
| 579 | /* end critical section */
|
---|
| 580 | if (pthread_mutex_unlock(&queuehead->mutex)!=0) qerr(QERR_MUTEXUNLOCK);
|
---|
| 581 | }
|
---|
| 582 | else
|
---|
| 583 | qerr(QERR_QINVALID);
|
---|
| 584 |
|
---|
| 585 | return result;
|
---|
| 586 | }
|
---|
| 587 |
|
---|
| 588 | int queue_is_expedited_enabled(queue_t *queuehead)
|
---|
| 589 | /** Get exp_enabled flag. */
|
---|
| 590 | {
|
---|
| 591 | int result = 0;
|
---|
| 592 |
|
---|
| 593 | if (queuehead != NULL)
|
---|
| 594 | {
|
---|
| 595 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
|
---|
| 596 | {
|
---|
| 597 | qerr(QERR_MUTEXLOCK);
|
---|
| 598 | return 0;
|
---|
| 599 | }
|
---|
| 600 | /* begin critical section */
|
---|
| 601 |
|
---|
| 602 | result = queuehead->exp_enabled;
|
---|
| 603 |
|
---|
| 604 | /* end critical section */
|
---|
| 605 | if (pthread_mutex_unlock(&queuehead->mutex)!=0) qerr(QERR_MUTEXUNLOCK);
|
---|
| 606 | }
|
---|
| 607 | else
|
---|
| 608 | qerr(QERR_QINVALID);
|
---|
| 609 |
|
---|
| 610 | return result;
|
---|
| 611 | }
|
---|
| 612 |
|
---|
| 613 | int queue_enable_expedited(queue_t *queuehead, int exp)
|
---|
| 614 | /** Set exp_enabled flag and return old value. */
|
---|
| 615 | {
|
---|
| 616 | int result = 0;
|
---|
| 617 |
|
---|
| 618 | if (queuehead != NULL)
|
---|
| 619 | {
|
---|
| 620 | if (pthread_mutex_lock(&queuehead->mutex)!=0)
|
---|
| 621 | {
|
---|
| 622 | qerr(QERR_MUTEXLOCK);
|
---|
| 623 | return 0;
|
---|
| 624 | }
|
---|
| 625 | /* begin critical section */
|
---|
| 626 |
|
---|
| 627 | result = queuehead->exp_enabled;
|
---|
| 628 | if (exp) queuehead->exp_enabled = 1;
|
---|
| 629 | else queuehead->exp_enabled = 0;
|
---|
| 630 |
|
---|
| 631 | /* end critical section */
|
---|
| 632 | if (pthread_mutex_unlock(&queuehead->mutex)!=0) qerr(QERR_MUTEXUNLOCK);
|
---|
| 633 | }
|
---|
| 634 | else
|
---|
| 635 | qerr(QERR_QINVALID);
|
---|
| 636 |
|
---|
| 637 | return result;
|
---|
| 638 | }
|
---|
| 639 |
|
---|
| 640 | //@}
|
---|