auto import from //depot/cupcake/@135843
diff --git a/libs/utils/SharedBuffer.cpp b/libs/utils/SharedBuffer.cpp
new file mode 100644
index 0000000..3555fb7
--- /dev/null
+++ b/libs/utils/SharedBuffer.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2005 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 <stdlib.h>
+#include <string.h>
+
+#include <utils/SharedBuffer.h>
+#include <utils/Atomic.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+
+SharedBuffer* SharedBuffer::alloc(size_t size)
+{
+ SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size));
+ if (sb) {
+ sb->mRefs = 1;
+ sb->mSize = size;
+ }
+ return sb;
+}
+
+
+ssize_t SharedBuffer::dealloc(const SharedBuffer* released)
+{
+ if (released->mRefs != 0) return -1; // XXX: invalid operation
+ free(const_cast<SharedBuffer*>(released));
+ return 0;
+}
+
+SharedBuffer* SharedBuffer::edit() const
+{
+ if (onlyOwner()) {
+ return const_cast<SharedBuffer*>(this);
+ }
+ SharedBuffer* sb = alloc(mSize);
+ if (sb) {
+ memcpy(sb->data(), data(), size());
+ release();
+ }
+ return sb;
+}
+
+SharedBuffer* SharedBuffer::editResize(size_t newSize) const
+{
+ if (onlyOwner()) {
+ SharedBuffer* buf = const_cast<SharedBuffer*>(this);
+ if (buf->mSize == newSize) return buf;
+ buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize);
+ if (buf != NULL) {
+ buf->mSize = newSize;
+ return buf;
+ }
+ }
+ SharedBuffer* sb = alloc(newSize);
+ if (sb) {
+ const size_t mySize = mSize;
+ memcpy(sb->data(), data(), newSize < mySize ? newSize : mySize);
+ release();
+ }
+ return sb;
+}
+
+SharedBuffer* SharedBuffer::attemptEdit() const
+{
+ if (onlyOwner()) {
+ return const_cast<SharedBuffer*>(this);
+ }
+ return 0;
+}
+
+SharedBuffer* SharedBuffer::reset(size_t new_size) const
+{
+ // cheap-o-reset.
+ SharedBuffer* sb = alloc(new_size);
+ if (sb) {
+ release();
+ }
+ return sb;
+}
+
+void SharedBuffer::acquire() const {
+ android_atomic_inc(&mRefs);
+}
+
+int32_t SharedBuffer::release(uint32_t flags) const
+{
+ int32_t prev = 1;
+ if (onlyOwner() || ((prev = android_atomic_dec(&mRefs)) == 1)) {
+ mRefs = 0;
+ if ((flags & eKeepStorage) == 0) {
+ free(const_cast<SharedBuffer*>(this));
+ }
+ }
+ return prev;
+}
+
+
+}; // namespace android