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media/omx-plugin/include/ics/utils/SharedBuffer.h@b8a032363ba2 (annotated)

media/omx-plugin/include/ics/utils/SharedBuffer.h

Thu, 22 Jan 2015 13:21:57 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 22 Jan 2015 13:21:57 +0100

branch

TOR_BUG_9701

changeset 15

b8a032363ba2

permissions

-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

michael@0	1	/*
michael@0	2	* Copyright (C) 2005 The Android Open Source Project
michael@0	3	*
michael@0	4	* Licensed under the Apache License, Version 2.0 (the "License");
michael@0	5	* you may not use this file except in compliance with the License.
michael@0	6	* You may obtain a copy of the License at
michael@0	7	*
michael@0	8	* http://www.apache.org/licenses/LICENSE-2.0
michael@0	9	*
michael@0	10	* Unless required by applicable law or agreed to in writing, software
michael@0	11	* distributed under the License is distributed on an "AS IS" BASIS,
michael@0	12	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0	13	* See the License for the specific language governing permissions and
michael@0	14	* limitations under the License.
michael@0	15	*/
michael@0	16
michael@0	17	#ifndef ANDROID_SHARED_BUFFER_H
michael@0	18	#define ANDROID_SHARED_BUFFER_H
michael@0	19
michael@0	20	#include <stdint.h>
michael@0	21	#include <sys/types.h>
michael@0	22
michael@0	23	// ---------------------------------------------------------------------------
michael@0	24
michael@0	25	namespace android {
michael@0	26
michael@0	27	class SharedBuffer
michael@0	28	{
michael@0	29	public:
michael@0	30
michael@0	31	/* flags to use with release() */
michael@0	32	enum {
michael@0	33	eKeepStorage = 0x00000001
michael@0	34	};
michael@0	35
michael@0	36	/*! allocate a buffer of size 'size' and acquire() it.
michael@0	37	* call release() to free it.
michael@0	38	*/
michael@0	39	static SharedBuffer* alloc(size_t size);
michael@0	40
michael@0	41	/*! free the memory associated with the SharedBuffer.
michael@0	42	* Fails if there are any users associated with this SharedBuffer.
michael@0	43	* In other words, the buffer must have been release by all its
michael@0	44	* users.
michael@0	45	*/
michael@0	46	static ssize_t dealloc(const SharedBuffer* released);
michael@0	47
michael@0	48	//! get the SharedBuffer from the data pointer
michael@0	49	static inline const SharedBuffer* sharedBuffer(const void* data);
michael@0	50
michael@0	51	//! access the data for read
michael@0	52	inline const void* data() const;
michael@0	53
michael@0	54	//! access the data for read/write
michael@0	55	inline void* data();
michael@0	56
michael@0	57	//! get size of the buffer
michael@0	58	inline size_t size() const;
michael@0	59
michael@0	60	//! get back a SharedBuffer object from its data
michael@0	61	static inline SharedBuffer* bufferFromData(void* data);
michael@0	62
michael@0	63	//! get back a SharedBuffer object from its data
michael@0	64	static inline const SharedBuffer* bufferFromData(const void* data);
michael@0	65
michael@0	66	//! get the size of a SharedBuffer object from its data
michael@0	67	static inline size_t sizeFromData(const void* data);
michael@0	68
michael@0	69	//! edit the buffer (get a writtable, or non-const, version of it)
michael@0	70	SharedBuffer* edit() const;
michael@0	71
michael@0	72	//! edit the buffer, resizing if needed
michael@0	73	SharedBuffer* editResize(size_t size) const;
michael@0	74
michael@0	75	//! like edit() but fails if a copy is required
michael@0	76	SharedBuffer* attemptEdit() const;
michael@0	77
michael@0	78	//! resize and edit the buffer, loose it's content.
michael@0	79	SharedBuffer* reset(size_t size) const;
michael@0	80
michael@0	81	//! acquire/release a reference on this buffer
michael@0	82	void acquire() const;
michael@0	83
michael@0	84	/*! release a reference on this buffer, with the option of not
michael@0	85	* freeing the memory associated with it if it was the last reference
michael@0	86	* returns the previous reference count
michael@0	87	*/
michael@0	88	int32_t release(uint32_t flags = 0) const;
michael@0	89
michael@0	90	//! returns wether or not we're the only owner
michael@0	91	inline bool onlyOwner() const;
michael@0	92
michael@0	93
michael@0	94	private:
michael@0	95	inline SharedBuffer() { }
michael@0	96	inline ~SharedBuffer() { }
michael@0	97	inline SharedBuffer(const SharedBuffer&);
michael@0	98
michael@0	99	// 16 bytes. must be sized to preserve correct alingment.
michael@0	100	mutable int32_t mRefs;
michael@0	101	size_t mSize;
michael@0	102	uint32_t mReserved[2];
michael@0	103	};
michael@0	104
michael@0	105	// ---------------------------------------------------------------------------
michael@0	106
michael@0	107	const SharedBuffer* SharedBuffer::sharedBuffer(const void* data) {
michael@0	108	return data ? reinterpret_cast<const SharedBuffer *>(data)-1 : 0;
michael@0	109	}
michael@0	110
michael@0	111	const void* SharedBuffer::data() const {
michael@0	112	return this + 1;
michael@0	113	}
michael@0	114
michael@0	115	void* SharedBuffer::data() {
michael@0	116	return this + 1;
michael@0	117	}
michael@0	118
michael@0	119	size_t SharedBuffer::size() const {
michael@0	120	return mSize;
michael@0	121	}
michael@0	122
michael@0	123	SharedBuffer* SharedBuffer::bufferFromData(void* data)
michael@0	124	{
michael@0	125	return ((SharedBuffer*)data)-1;
michael@0	126	}
michael@0	127
michael@0	128	const SharedBuffer* SharedBuffer::bufferFromData(const void* data)
michael@0	129	{
michael@0	130	return ((const SharedBuffer*)data)-1;
michael@0	131	}
michael@0	132
michael@0	133	size_t SharedBuffer::sizeFromData(const void* data)
michael@0	134	{
michael@0	135	return (((const SharedBuffer*)data)-1)->mSize;
michael@0	136	}
michael@0	137
michael@0	138	bool SharedBuffer::onlyOwner() const {
michael@0	139	return (mRefs == 1);
michael@0	140	}
michael@0	141
michael@0	142	}; // namespace android
michael@0	143
michael@0	144	// ---------------------------------------------------------------------------
michael@0	145
michael@0	146	#endif // ANDROID_VECTOR_H