Merge-in RTEMS port patch by Phil Torre <ptorre@zetron.com>, alpha release.

git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@433 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 162 insertions, 0 deletions

diff --git a/pjlib/src/pj/os_rwmutex.c b/pjlib/src/pj/os_rwmutex.c
new file mode 100644
index 00000000..2ec147f0
--- /dev/null
+++ b/pjlib/src/pj/os_rwmutex.c
@@ -0,0 +1,162 @@
+/* $Id$ */
+/* 
+ * Copyright (C)2003-2006 Benny Prijono <benny@prijono.org>
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+ */
+
+/* 
+ * Note: 
+ * 
+ * DO NOT BUILD THIS FILE DIRECTLY. THIS FILE WILL BE INCLUDED BY os_core_*.c
+ * WHEN MACRO PJ_EMULATE_RWMUTEX IS SET.
+ */
+
+/*
+ * os_rwmutex.c:
+ *
+ * Implementation of Read-Write mutex for platforms that lack it (e.g.
+ * Win32, RTEMS).
+ */
+
+
+struct pj_rwmutex_t
+{
+    pj_mutex_t *read_lock;
+    /* write_lock must use semaphore, because write_lock may be released
+     * by thread other than the thread that acquire the write_lock in the
+     * first place.
+     */
+    pj_sem_t   *write_lock;
+    pj_int32_t  reader_count;
+};
+
+/*
+ * Create reader/writer mutex.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_create(pj_pool_t *pool, const char *name,
+				      pj_rwmutex_t **p_mutex)
+{
+    pj_status_t status;
+    pj_rwmutex_t *rwmutex;
+
+    PJ_ASSERT_RETURN(pool && p_mutex, PJ_EINVAL);
+
+    *p_mutex = NULL;
+    rwmutex = pj_pool_alloc(pool, sizeof(struct pj_rwmutex_t));
+
+    status = pj_mutex_create_simple(pool, name, &rwmutex ->read_lock);
+    if (status != PJ_SUCCESS)
+	return status;
+
+    status = pj_sem_create(pool, name, 1, 1, &rwmutex->write_lock);
+    if (status != PJ_SUCCESS) {
+	pj_mutex_destroy(rwmutex->read_lock);
+	return status;
+    }
+
+    rwmutex->reader_count = 0;
+    *p_mutex = rwmutex;
+    return PJ_SUCCESS;
+}
+
+/*
+ * Lock the mutex for reading.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_lock_read(pj_rwmutex_t *mutex)
+{
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(mutex, PJ_EINVAL);
+
+    status = pj_mutex_lock(mutex->read_lock);
+    if (status != PJ_SUCCESS) {
+	pj_assert(!"This pretty much is unexpected");
+	return status;
+    }
+
+    mutex->reader_count++;
+
+    pj_assert(mutex->reader_count < 0x7FFFFFF0L);
+
+    if (mutex->reader_count == 1)
+	pj_sem_wait(mutex->write_lock);
+
+    status = pj_mutex_unlock(mutex->read_lock);
+    return status;
+}
+
+/*
+ * Lock the mutex for writing.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_lock_write(pj_rwmutex_t *mutex)
+{
+    PJ_ASSERT_RETURN(mutex, PJ_EINVAL);
+    return pj_sem_wait(mutex->write_lock);
+}
+
+/*
+ * Release read lock.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_unlock_read(pj_rwmutex_t *mutex)
+{
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(mutex, PJ_EINVAL);
+
+    status = pj_mutex_lock(mutex->read_lock);
+    if (status != PJ_SUCCESS) {
+	pj_assert(!"This pretty much is unexpected");
+	return status;
+    }
+
+    pj_assert(mutex->reader_count >= 1);
+
+    --mutex->reader_count;
+    if (mutex->reader_count == 0)
+	pj_sem_post(mutex->write_lock);
+
+    status = pj_mutex_unlock(mutex->read_lock);
+    return status;
+}
+
+/*
+ * Release write lock.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_unlock_write(pj_rwmutex_t *mutex)
+{
+    PJ_ASSERT_RETURN(mutex, PJ_EINVAL);
+    pj_assert(mutex->reader_count <= 1);
+    return pj_sem_post(mutex->write_lock);
+}
+
+
+/*
+ * Destroy reader/writer mutex.
+ *
+ */
+PJ_DEF(pj_status_t) pj_rwmutex_destroy(pj_rwmutex_t *mutex)
+{
+    PJ_ASSERT_RETURN(mutex, PJ_EINVAL);
+    pj_mutex_destroy(mutex->read_lock);
+    pj_sem_destroy(mutex->write_lock);
+    return PJ_SUCCESS;
+}
+