chore: import upstream snapshot with attribution

libnd4j/include/helpers/impl/SimpleReadWriteLock.cpp

@@ -0,0 +1,66 @@
+/* ******************************************************************************
+ *
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Apache License, Version 2.0 which is available at
+ * https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ *  See the NOTICE file distributed with this work for additional
+ *  information regarding copyright ownership.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ ******************************************************************************/
+
+//
+// Created by raver on 8/29/2018.
+//
+#include <helpers/SimpleReadWriteLock.h>
+
+namespace sd {
+SimpleReadWriteLock::SimpleReadWriteLock(const SimpleReadWriteLock& other) {
+  _read_locks.store(other._read_locks.load());
+  _write_locks.store(other._write_locks.load());
+}
+
+SimpleReadWriteLock::SimpleReadWriteLock() {
+  _read_locks.store(0);
+  _write_locks.store(0);
+}
+
+void SimpleReadWriteLock::lockRead() {
+  _mutex.lock();
+  _read_locks++;
+  while (_write_locks.load() > 0) {
+    // just loop
+  }
+  _mutex.unlock();
+}
+
+void SimpleReadWriteLock::unlockRead() { _read_locks--; }
+
+// write lock
+void SimpleReadWriteLock::lockWrite() {
+  _mutex.lock();
+  _write_locks++;
+  while (_read_locks.load() > 0) {
+    // just loop
+  }
+  _mutex.unlock();
+}
+
+void SimpleReadWriteLock::unlockWrite() { _write_locks--; }
+
+SimpleReadWriteLock& SimpleReadWriteLock::operator=(const SimpleReadWriteLock& other) {
+  if (this == &other) return *this;
+
+  this->_write_locks.store(other._write_locks.load());
+  this->_read_locks.store(other._read_locks.load());
+
+  return *this;
+}
+}  // namespace sd