Add a standardized shared memory type
This adds a simple SharedFileRegion type that can be used to pass blocks
of shared memory between processes in a structured AIDL interface.
In addition a small utility library is provided for interfacing with
existing code that uses IMemory.
The intention is to add utilities for direct usage of the memory
content.
Bug: 160253486
Test: Ran the included unit test. Integration testing as part of whole
topic tests via the audio effect tests.
Change-Id: I3f923047e364ba44fda316bdd563561ebec201b2
diff --git a/media/libshmem/ShmemUtil.cpp b/media/libshmem/ShmemUtil.cpp
new file mode 100644
index 0000000..a6d047f
--- /dev/null
+++ b/media/libshmem/ShmemUtil.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+#include "media/ShmemUtil.h"
+
+namespace android {
+namespace media {
+
+bool validateSharedFileRegion(const SharedFileRegion& shmem) {
+ // Size and offset must be non-negative.
+ if (shmem.size < 0 || shmem.offset < 0) {
+ return false;
+ }
+
+ uint64_t size = shmem.size;
+ uint64_t offset = shmem.offset;
+
+ // Must not wrap.
+ if (offset > offset + size) {
+ return false;
+ }
+
+ return true;
+}
+
+} // namespace media
+} // namespace android