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Diffstat (limited to 'media/omx-plugin/include/ics/utils/SharedBuffer.h')
-rw-r--r-- | media/omx-plugin/include/ics/utils/SharedBuffer.h | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/media/omx-plugin/include/ics/utils/SharedBuffer.h b/media/omx-plugin/include/ics/utils/SharedBuffer.h new file mode 100644 index 000000000..24508b0f7 --- /dev/null +++ b/media/omx-plugin/include/ics/utils/SharedBuffer.h @@ -0,0 +1,146 @@ +/* + * 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. + */ + +#ifndef ANDROID_SHARED_BUFFER_H +#define ANDROID_SHARED_BUFFER_H + +#include <stdint.h> +#include <sys/types.h> + +// --------------------------------------------------------------------------- + +namespace android { + +class SharedBuffer +{ +public: + + /* flags to use with release() */ + enum { + eKeepStorage = 0x00000001 + }; + + /*! allocate a buffer of size 'size' and acquire() it. + * call release() to free it. + */ + static SharedBuffer* alloc(size_t size); + + /*! free the memory associated with the SharedBuffer. + * Fails if there are any users associated with this SharedBuffer. + * In other words, the buffer must have been release by all its + * users. + */ + static ssize_t dealloc(const SharedBuffer* released); + + //! get the SharedBuffer from the data pointer + static inline const SharedBuffer* sharedBuffer(const void* data); + + //! access the data for read + inline const void* data() const; + + //! access the data for read/write + inline void* data(); + + //! get size of the buffer + inline size_t size() const; + + //! get back a SharedBuffer object from its data + static inline SharedBuffer* bufferFromData(void* data); + + //! get back a SharedBuffer object from its data + static inline const SharedBuffer* bufferFromData(const void* data); + + //! get the size of a SharedBuffer object from its data + static inline size_t sizeFromData(const void* data); + + //! edit the buffer (get a writtable, or non-const, version of it) + SharedBuffer* edit() const; + + //! edit the buffer, resizing if needed + SharedBuffer* editResize(size_t size) const; + + //! like edit() but fails if a copy is required + SharedBuffer* attemptEdit() const; + + //! resize and edit the buffer, loose it's content. + SharedBuffer* reset(size_t size) const; + + //! acquire/release a reference on this buffer + void acquire() const; + + /*! release a reference on this buffer, with the option of not + * freeing the memory associated with it if it was the last reference + * returns the previous reference count + */ + int32_t release(uint32_t flags = 0) const; + + //! returns wether or not we're the only owner + inline bool onlyOwner() const; + + +private: + inline SharedBuffer() { } + inline ~SharedBuffer() { } + inline SharedBuffer(const SharedBuffer&); + + // 16 bytes. must be sized to preserve correct alingment. + mutable int32_t mRefs; + size_t mSize; + uint32_t mReserved[2]; +}; + +// --------------------------------------------------------------------------- + +const SharedBuffer* SharedBuffer::sharedBuffer(const void* data) { + return data ? reinterpret_cast<const SharedBuffer *>(data)-1 : 0; +} + +const void* SharedBuffer::data() const { + return this + 1; +} + +void* SharedBuffer::data() { + return this + 1; +} + +size_t SharedBuffer::size() const { + return mSize; +} + +SharedBuffer* SharedBuffer::bufferFromData(void* data) +{ + return ((SharedBuffer*)data)-1; +} + +const SharedBuffer* SharedBuffer::bufferFromData(const void* data) +{ + return ((const SharedBuffer*)data)-1; +} + +size_t SharedBuffer::sizeFromData(const void* data) +{ + return (((const SharedBuffer*)data)-1)->mSize; +} + +bool SharedBuffer::onlyOwner() const { + return (mRefs == 1); +} + +}; // namespace android + +// --------------------------------------------------------------------------- + +#endif // ANDROID_VECTOR_H |