ReadArraySampleCache.h

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//-*****************************************************************************
//
// Copyright (c) 2009-2012,
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//-*****************************************************************************

#ifndef Alembic_AbcCoreAbstract_ReadArraySampleCache_h
#define Alembic_AbcCoreAbstract_ReadArraySampleCache_h

#include <Alembic/Util/Export.h>
#include <Alembic/AbcCoreAbstract/Foundation.h>
#include <Alembic/AbcCoreAbstract/ArraySample.h>

namespace Alembic {
namespace AbcCoreAbstract {
namespace ALEMBIC_VERSION_NS {

//-*****************************************************************************
//! A ReadArraySampleID is a bundle that contains a pointer to the
//! \ref ArraySample itself, along with the sample's key.
class ReadArraySampleID
{
public:
    //! By convention, we define the typedef this_type. This
    //! is used by the unspecified-bool-type cast below.
    typedef ReadArraySampleID this_type;
    
    //! Default constructor creates empty ID
    //! ...
    ReadArraySampleID() {}

    //! Explicit constructor creates ID with key and sample
    ReadArraySampleID( const ArraySample::Key &iSampleKey,
                       ArraySamplePtr iSample )
      : m_sampleKey( iSampleKey ),
        m_sample( iSample ) {}

    //! Default copy constructor
    //! Default assignment operator.

    //! Return the sample key
    //! ...
    const ArraySample::Key &getKey() const
    { return m_sampleKey; }

    //! Return the sample itself.
    //! ...
    ArraySamplePtr getSample() const
    { return m_sample; }

    //! Return whether or not this read sample is valid
    //! ...
    bool valid() const
    {
        return ( m_sample && m_sample->valid() );
    }

    //! Unspecified bool type cast
    //! ...
    ALEMBIC_OPERATOR_BOOL( valid() );

private:
    ArraySample::Key m_sampleKey;
    ArraySamplePtr m_sample;
};


//-*****************************************************************************
//-*****************************************************************************
//-*****************************************************************************
// READ ARRAY SAMPLE CACHE
//-*****************************************************************************
//-*****************************************************************************
//-*****************************************************************************

//-*****************************************************************************
//! Alembic caches array samples based on a Murmur3 128bit checksum key.
//! This is an abstract interface to these caches, which can be implemented
//! in any number of ways.
class ALEMBIC_EXPORT ReadArraySampleCache
    : private Alembic::Util::noncopyable
    , public Alembic::Util::enable_shared_from_this<ReadArraySampleCache>
{
public:
    //! Virtual destructor
    //! ...
    virtual ~ReadArraySampleCache();

    //! If it finds the entry, return a valid pointer to it which
    //! is expected to lock the entry in the cache until the pointer
    //! is dereferenced.
    virtual ReadArraySampleID find( const ArraySample::Key &iKey ) = 0;

    //! Store an entry given an explicit set of storage.
    //! The magnificent flexibility of the shared_ptr class makes
    //! it possible for an ArraySamplePtr to contain its own destructor
    //! as a custom deleter, and thus we can use ArraySamplePtrs for
    //! both reference and ownership, depending on the deleter.
    //! In this case, it is assumed that iSamp represents
    //! "owned" data, rather than a reference.  The data will not
    //! be copied, but rather this sample will be stored directly
    //! using the passed shared_ptr.
    virtual ReadArraySampleID store( const ArraySample::Key &iKey,
                                     ArraySamplePtr iSamp ) = 0;
};

//-*****************************************************************************
typedef Alembic::Util::shared_ptr<ReadArraySampleCache> ReadArraySampleCachePtr;

} // End namespace ALEMBIC_VERSION_NS

using namespace ALEMBIC_VERSION_NS;

} // End namespace AbcCoreAbstract
} // End namespace Alembic

#endif