genesis-3d_engine/Engine/foundation/io/stream.h

/****************************************************************************
Copyright (c) 2006, Radon Labs GmbH
Copyright (c) 2011-2013,WebJet Business Division,CYOU
 
http://www.genesis-3d.com.cn

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****************************************************************************/
#pragma once
#ifndef IO_STREAM_H
#define IO_STREAM_H
//------------------------------------------------------------------------------
/**
    @class IO::Stream
    
    Offers an abstract interface for read/write access to a sequence of bytes.
    Base class for all classes which need to provide a read/write interface
    to data, like a FileStream, a MemoryStream, etc...
    
    Stream objects can be accessed directly, or through stream reader and
    writer classes, which offer specific read/writing interfaces to streams.
*/
#include "core/refcounted.h"
#include "io/uri.h"
#include "threading/criticalsection.h"
#include "io/mediatype.h"

//------------------------------------------------------------------------------
namespace IO
{
	// - forward declare 
	class Stream;
	typedef GPtr<Stream> TStreamPtr;

class Stream : public Core::RefCounted
{
    __DeclareClass(Stream);
public:
    /// typedefs
    typedef int Position;       // DON'T DEFINE AS UNSIGNED!
    typedef int Offset;         // DON'T DEFINE AS UNSIGNED!
    typedef int Size;           // DON'T DEFINE AS UNSIGNED!

    /// access modes
    enum AccessMode
    {
        ReadAccess,
        WriteAccess,
        AppendAccess,
        ReadWriteAccess,
    };

    /// access prefered pattern
    enum AccessPattern
    {
        Random,
        Sequential,
    };

    /// seek origins
    enum SeekOrigin
    {
        Begin,
        Current,
        End,
    };
    /// constructor
    Stream();
    /// destructor
    virtual ~Stream();
    /// set stream location as URI
    void SetURI(const URI& u);
    /// get stream URI
    const URI& GetURI() const;
    /// return true if the stream supports reading
    virtual bool CanRead() const;
    /// return true if the stream supports writing
    virtual bool CanWrite() const;
    /// return true if the stream supports seeking
    virtual bool CanSeek() const;
    /// return true if the stream provides direct memory access
    virtual bool CanBeMapped() const;
    /// set a new size for the stream
    virtual void SetSize(Size s);
    /// get the size of the stream in bytes
    virtual Size GetSize() const;
    /// get the current position of the read/write cursor
    virtual Position GetPosition() const;
    /// set the access mode of the stream (default is ReadAccess)
    void SetAccessMode(AccessMode m);
    /// get the access mode of the stream
    AccessMode GetAccessMode() const;
    /// set the prefered access pattern (default is Sequential)
    void SetAccessPattern(AccessPattern p);
    /// get the prefered access pattern
    AccessPattern GetAccessPattern() const;
    /// set optional media type of stream content
    void SetMediaType(const MediaType& t);
    /// get optional media type
    const MediaType& GetMediaType() const;
    /// open the stream
    virtual bool Open();
    /// close the stream
    virtual void Close();
    /// return true if currently open
    bool IsOpen() const;
    /// directly write to the stream
    virtual void Write(const void* ptr, Size numBytes);
    /// directly read from the stream
    virtual Size Read(void* ptr, Size numBytes);
    /// seek in stream
    virtual void Seek(Offset offset, SeekOrigin origin);
    /// flush unsaved data
    virtual void Flush();
    /// return true if end-of-stream reached
    virtual bool Eof() const;
    /// map stream to memory
    virtual void* Map();
    /// unmap stream
    virtual void Unmap();
	/// copy data to memory 
	virtual Size Copy( void* ptr, Size numBytes )const;
    /// return true if stream is currently mapped to memory
    bool IsMapped() const;
	/// return true if stream header is the same to headerPtr
	virtual bool IsHeader( void* headPtr, Size numBytes );
        
protected:
    URI uri;
    AccessMode accessMode;
    AccessPattern accessPattern;
    bool isOpen;
    bool isMapped;
    MediaType mediaType;
};

} // namespace IO
//------------------------------------------------------------------------------
#endif