src/tlsproxy.c: Add thread support.

[tlsproxy/tlsproxy.git] / src / sem.c

diff --git a/src/sem.c b/src/sem.c
new file mode 100644 (file)
index 0000000..86fe398
--- /dev/null
+++ b/src/sem.c
@@ -0,0 +1,84 @@
+/*
+ * Simple semaphore implementation, P() and V().
+ *
+ * Copyright (C) 2011  Simon Ruderich
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <pthread.h>
+
+#include "sem.h"
+
+
+struct SEM {
+    pthread_mutex_t mutex;
+    pthread_cond_t  condition;
+    int value;
+};
+
+SEM *sem_init(int init_value) {
+    SEM *sem = (SEM *)malloc(sizeof(SEM));
+    if (NULL == sem) {
+        return NULL;
+    }
+
+    if (0 != pthread_mutex_init(&sem->mutex, NULL)) {
+        free(sem);
+        return NULL;
+    }
+    if (0 != pthread_cond_init(&sem->condition, NULL)) {
+        pthread_mutex_destroy(&sem->mutex);
+        free(sem);
+        return NULL;
+    }
+
+    sem->value = init_value;
+    return sem;
+}
+
+int sem_del(SEM *sem) {
+    if (NULL == sem) {
+        return 0;
+    }
+
+    if (0 != pthread_mutex_destroy(&sem->mutex)) {
+        free(sem);
+        return -1;
+    }
+    if (0 != pthread_cond_destroy(&sem->condition)) {
+        free(sem);
+        return -1;
+    }
+
+    free(sem);
+    return 0;
+}
+
+void P(SEM *sem) {
+    pthread_mutex_lock(&sem->mutex);
+    while (0 == sem->value) {
+        pthread_cond_wait(&sem->condition, &sem->mutex);
+    }
+    sem->value--;
+    pthread_mutex_unlock(&sem->mutex);
+}
+
+void V(SEM *sem) {
+    pthread_mutex_lock(&sem->mutex);
+    sem->value++;
+    pthread_cond_broadcast(&sem->condition);
+    pthread_mutex_unlock(&sem->mutex);
+}