183 lines
4.6 KiB
C++
183 lines
4.6 KiB
C++
/*
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STREAMTYPE.hpp - classification of media stream types
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Copyright (C) Lumiera.org
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2008, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file streamtype.hpp
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** Framework for classification of media streams.
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** Besides the actual implementation type of a media stream, the Proc-Layer
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** needs a more general way for accessing, comparing and manipulating media streams
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** based on type information.
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**
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** @see control::STypeManager
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**
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*/
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#ifndef LUMIERA_STREAMTYPE_HPP
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#define LUMIERA_STREAMTYPE_HPP
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#include "common/query.hpp"
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#include <boost/noncopyable.hpp>
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namespace lumiera {
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/**
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*
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*/
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struct StreamType : boost::noncopyable
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{
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enum MediaKind
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{
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VIDEO,
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IMMAGE,
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AUDIO,
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MIDI
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};
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enum Usage
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{
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RAW,
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SOURCE,
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TARGET,
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INTERMEDIARY
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};
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struct Prototype;
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class ImplFacade;
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class ImplConstraint;
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Prototype const& prototype;
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ImplFacade * implType; /////////////TODO: really by ptr???
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Usage intentionTag;
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};
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/**
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*
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*/
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struct StreamType::Prototype
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{
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Symbol id;
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MediaKind kind;
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bool subsumes (Prototype const& other) const;
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bool canRender (Prototype const& other) const;
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};
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/**
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* A (more or less) concrete implementation type, wired up
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* as a facade providing the basic set of operations.
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*/
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class StreamType::ImplFacade
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{
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public:
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Symbol libraryID;
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class TypeTag ;
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/** placeholder definition for the contents of a data buffer */
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struct DataBuffer { };
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virtual bool operator== (ImplFacade const& other) const =0;
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virtual bool operator== (StreamType const& other) const =0;
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virtual bool canConvert (ImplFacade const& other) const =0;
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virtual bool canConvert (StreamType const& other) const =0;
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virtual DataBuffer* createFrame () const =0;
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virtual MediaKind getKind() const =0;
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virtual ~ImplFacade() {};
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protected:
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ImplFacade (Symbol libID) ;
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};
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/**
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* Special case of an implementation type being only partialiy specified
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* Besides requiring some aspect of the implementation type, there is the
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* promise to fill in defaults to build a complete implementation type
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* if necessary.
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*/
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class StreamType::ImplConstraint
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: public StreamType::ImplFacade
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{
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public:
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virtual bool canConvert (ImplFacade const& other) const =0;
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virtual bool canConvert (StreamType const& other) const =0;
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virtual bool subsumes (ImplFacade const& other) const =0;
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/** modify the other impl type such as to comply with this constraint */
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virtual void makeCompliant (ImplFacade & other) const =0;
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/** create a default impl type in accordance to this constraint
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* and use it to create a new framebuffer */
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virtual DataBuffer* createFrame () const =0;
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/** similarily create a impl type which complies to this constraint
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* as well as to the additional constraints (e.g. frame size).
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* Create a new framebuffer of the resutling type */
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virtual DataBuffer* createFrame (ImplConstraint const& furtherConstraints) const =0;
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//TODO: do we need functions to represent and describe this constraint?
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};
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/**
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* opaque placeholder (type erasure)
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* for implementation specific type info.
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* Intended to be passed to a concrete
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* MediaImplLib to build an ImplFacade.
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*/
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class StreamType::ImplFacade::TypeTag
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{
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void* rawTypeStruct_;
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public:
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Symbol libraryID;
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template<class TY>
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TypeTag (Symbol lID, TY& rawType)
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: rawTypeStruct_(&rawType),
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libraryID(lID)
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{ }
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};
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} // namespace lumiera
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#endif
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