1 | /* |
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2 | * |
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3 | * Copyright (c) 2007-2016 The University of Waikato, Hamilton, New Zealand. |
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4 | * All rights reserved. |
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5 | * |
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6 | * This file is part of libtrace. |
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7 | * |
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8 | * This code has been developed by the University of Waikato WAND |
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9 | * research group. For further information please see http://www.wand.net.nz/ |
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10 | * |
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11 | * libtrace is free software; you can redistribute it and/or modify |
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12 | * it under the terms of the GNU Lesser General Public License as published by |
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13 | * the Free Software Foundation; either version 3 of the License, or |
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14 | * (at your option) any later version. |
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15 | * |
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16 | * libtrace is distributed in the hope that it will be useful, |
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17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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19 | * GNU Lesser General Public License for more details. |
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20 | * |
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21 | * You should have received a copy of the GNU Lesser General Public License |
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22 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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23 | * |
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24 | * |
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25 | */ |
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26 | #include "deque.h" |
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27 | |
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28 | #include <assert.h> |
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29 | #include <stddef.h> |
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30 | #include <stdlib.h> |
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31 | #include <string.h> |
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32 | |
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33 | |
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34 | /* Ensure we don't do any reads without locking even if we *know* that |
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35 | * any write will be atomic */ |
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36 | #ifndef RACE_SAFE |
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37 | #define RACE_SAFE 1 |
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38 | #endif |
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39 | |
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40 | struct list_node { |
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41 | list_node_t * next; |
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42 | list_node_t * prev; |
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43 | char data[]; // Our item goes here |
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44 | }; |
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45 | |
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46 | DLLEXPORT void libtrace_deque_init(libtrace_queue_t * q, size_t element_size) |
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47 | { |
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48 | q->head = NULL; |
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49 | q->tail = NULL; |
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50 | q->size = 0; |
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51 | q->element_size = element_size; |
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52 | ASSERT_RET(pthread_mutex_init(&q->lock, NULL), == 0); |
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53 | } |
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54 | |
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55 | DLLEXPORT void libtrace_deque_push_back(libtrace_queue_t *q, void *d) |
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56 | { |
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57 | // Do as much work as possible outside the lock |
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58 | list_node_t * new_node = (list_node_t *) malloc(sizeof(list_node_t) + q->element_size); |
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59 | new_node->next = NULL; |
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60 | // Fill it |
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61 | memcpy(&new_node->data, d, q->element_size); |
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62 | // Only ->prev is unknown at this stage to be completed in lock |
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63 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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64 | if (q->head == NULL) { |
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65 | if (q->tail != NULL || q->size != 0) { |
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66 | fprintf(stderr, "Error deque head cannot be NULL with a non NULL tail and size of more than 0 in libtrace_deque_push_back()\n"); |
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67 | return; |
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68 | } |
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69 | new_node->prev = NULL; |
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70 | q->head = q->tail = new_node; |
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71 | } else { |
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72 | if (q->tail == NULL) { |
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73 | fprintf(stderr, "Error deque tail cannot be NULL if it contains a head in libtrace_deque_push_back()\n"); |
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74 | return; |
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75 | } |
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76 | q->tail->next = new_node; |
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77 | new_node->prev = q->tail; // Done the double link |
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78 | q->tail = new_node; // Relink tail |
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79 | } |
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80 | q->size++; |
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81 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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82 | } |
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83 | |
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84 | DLLEXPORT void libtrace_deque_push_front(libtrace_queue_t *q, void *d) |
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85 | { |
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86 | // Do as much work as possible outside the lock |
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87 | list_node_t * new_node = (list_node_t *) malloc(sizeof(list_node_t) + q->element_size); |
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88 | new_node->prev = NULL; |
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89 | // Fill it |
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90 | memcpy(&new_node->data, d, q->element_size); |
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91 | // Only ->next is unknown at this stage to be completed in lock |
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92 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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93 | if (q->head == NULL) { |
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94 | if (q->tail != NULL || q->size != 0) { |
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95 | fprintf(stderr, "Error deque head cannot be NULL with a non NULL tail and size of more than 0 in libtrace_deque_push_front()\n"); |
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96 | return; |
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97 | } |
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98 | new_node->next = NULL; |
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99 | q->head = q->tail = new_node; |
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100 | } else { |
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101 | q->head->prev = new_node; |
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102 | new_node->next = q->head; // Done the double link |
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103 | q->head = new_node; // Relink head |
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104 | // Void out the other things |
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105 | } |
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106 | q->size++; |
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107 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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108 | } |
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109 | |
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110 | DLLEXPORT int libtrace_deque_peek_front(libtrace_queue_t *q, void *d) |
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111 | { |
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112 | int ret = 1; |
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113 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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114 | if (q->head == NULL) |
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115 | ret = 0; |
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116 | else |
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117 | memcpy(d, &q->head->data, q->element_size); |
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118 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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119 | return ret; |
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120 | } |
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121 | |
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122 | DLLEXPORT int libtrace_deque_peek_tail(libtrace_queue_t *q, void *d) |
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123 | { |
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124 | int ret = 1; |
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125 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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126 | if (q->tail == NULL) |
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127 | ret = 0; |
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128 | else |
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129 | memcpy(d, &q->tail->data, q->element_size); |
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130 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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131 | return ret; |
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132 | } |
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133 | |
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134 | DLLEXPORT int libtrace_deque_pop_front(libtrace_queue_t *q, void *d) |
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135 | { |
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136 | int ret = 0; |
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137 | list_node_t * n = NULL; |
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138 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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139 | if (q->head != NULL) { |
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140 | n = q->head; |
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141 | ret = 1; |
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142 | q->head = n->next; |
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143 | if (q->head) |
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144 | q->head->prev = NULL; |
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145 | q->size--; |
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146 | if (q->size <= 1) // Either 1 or 0 items |
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147 | q->tail = q->head; |
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148 | } |
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149 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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150 | // Unlock once we've removed it :) |
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151 | if (ret) { |
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152 | memcpy(d, &n->data, q->element_size); |
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153 | free(n); |
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154 | } |
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155 | return ret; |
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156 | } |
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157 | |
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158 | DLLEXPORT int libtrace_deque_pop_tail(libtrace_queue_t *q, void *d) |
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159 | { |
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160 | int ret = 0; |
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161 | list_node_t * n=NULL; |
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162 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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163 | if (q->tail != NULL) { |
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164 | n = q->tail; |
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165 | ret = 1; |
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166 | q->tail = n->prev; |
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167 | if (q->tail) |
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168 | q->tail->next = NULL; |
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169 | q->size--; |
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170 | if (q->size <= 1) // Either 1 or 0 items |
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171 | q->head = q->tail; |
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172 | } |
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173 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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174 | if (ret) { |
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175 | memcpy(d, &n->data, q->element_size); |
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176 | free(n); |
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177 | } |
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178 | return ret; |
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179 | } |
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180 | |
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181 | DLLEXPORT size_t libtrace_deque_get_size(libtrace_queue_t *q) |
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182 | { |
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183 | #if RACE_SAFE |
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184 | size_t ret; |
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185 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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186 | ret = q->size; |
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187 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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188 | return ret; |
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189 | #else |
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190 | return q->size; |
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191 | #endif |
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192 | } |
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193 | |
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194 | DLLEXPORT void libtrace_zero_deque(libtrace_queue_t *q) |
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195 | { |
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196 | q->head = q->tail = NULL; |
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197 | q->size = q->element_size = 0; |
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198 | } |
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199 | |
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200 | DLLEXPORT void libtrace_deque_apply_function(libtrace_queue_t *q, deque_data_fn fn) |
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201 | { |
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202 | list_node_t *n; |
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203 | ASSERT_RET(pthread_mutex_lock(&q->lock), == 0); |
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204 | n = q->head; |
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205 | for (n = q->head; n != NULL; n = n->next) { |
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206 | (*fn)(&n->data); |
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207 | } |
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208 | ASSERT_RET(pthread_mutex_unlock(&q->lock), == 0); |
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209 | } |
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