1 files changed, 113 insertions, 0 deletions
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