Added SilcRwLock, a read/write lock API.

[silc.git] / lib / silcutil / win32 / silcwin32thread.c

diff --git a/lib/silcutil/win32/silcwin32thread.c b/lib/silcutil/win32/silcwin32thread.c
index 97e516bcc6ceeea5d3ede7bda015767c75458729..d54a13e6c83088fd13ca9f8be2c359e5f7fa5d5c 100644 (file)
--- a/lib/silcutil/win32/silcwin32thread.c
+++ b/lib/silcutil/win32/silcwin32thread.c
@@ -4,7 +4,7 @@
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 2001 - 2006 Pekka Riikonen
+  Copyright (C) 2001 - 2007 Pekka Riikonen
 
   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
@@ -211,6 +211,94 @@ void silc_mutex_assert_locked(SilcMutex mutex)
 }
 
 
+/***************************** SILC Rwlock API ******************************/
+
+/* SILC read/write lock structure */
+struct SilcRwLockStruct {
+#ifdef SILC_THREADS
+  SilcMutex mutex;
+  SilcCond cond;
+#endif /* SILC_THREADS */
+  unsigned int readers : 31;
+  unsigned int locked  : 1;
+};
+
+SilcBool silc_rwlock_alloc(SilcRwLock *rwlock)
+{
+#ifdef SILC_THREADS
+  *rwlock = silc_calloc(1, sizeof(**rwlock));
+  if (!(*rwlock))
+    return FALSE;
+  if (!silc_mutex_alloc(&(*rwlock)->mutex)) {
+    silc_free(*rwlock);
+    return FALSE;
+  }
+  if (!silc_cond_alloc(&(*rwlock)->cond)) {
+    silc_mutex_free((*rwlock)->mutex);
+    silc_free(*rwlock);
+    return FALSE;
+  }
+  return TRUE;
+#else
+  return FALSE;
+#endif /* SILC_THREADS */
+}
+
+void silc_rwlock_free(SilcRwLock rwlock)
+{
+#ifdef SILC_THREADS
+  if (mutex) {
+    silc_mutex_free(rwlock->mutex);
+    silc_cond_free(rwlock->cond);
+    silc_free(rwlock);
+  }
+#endif /* SILC_THREADS */
+}
+
+void silc_rwlock_rdlock(SilcRwLock rwlock)
+{
+#ifdef SILC_THREADS
+  if (rwlock) {
+    silc_mutex_lock(rwlock->mutex);
+    rwlock->readers++;
+    silc_mutex_unlock(rwlock->mutex);
+  }
+#endif /* SILC_THREADS */
+}
+
+void silc_rwlock_wrlock(SilcRwLock rwlock)
+{
+#ifdef SILC_THREADS
+  if (rwlock) {
+    silc_mutex_lock(rwlock->mutex);
+    while (rwlock->readers > 0)
+      silc_cond_wait(rwlock->cond, rwlock->mutex);
+    rwlock->locked = TRUE;
+  }
+#endif /* SILC_THREADS */
+}
+
+void silc_rwlock_unlock(SilcRwLock rwlock)
+{
+#ifdef SILC_THREADS
+  if (rwlock) {
+    if (rwlock->locked) {
+      /* Unlock writer */
+      rwlock->locked = FALSE;
+      silc_mutex_unlock(rwlock->mutex);
+      return;
+    }
+
+    /* Unlock reader */
+    silc_mutex_lock(rwlock->mutex);
+    rwlock->readers--;
+    silc_cond_broadcast(rwlock->cond);
+    silc_mutex_unlock(rwlock->mutex);
+  }
+#endif /* SILC_THREADS */
+}
+
+
 /**************************** SILC Cond API ******************************/
 
 /* SILC Conditional Variable context */
@@ -294,4 +382,5 @@ SilcBool silc_cond_timedwait(SilcCond cond, SilcMutex mutex,
     }
   }
 #endif /* SILC_THREADS*/
+  return TRUE;
 }