OgreDataStream.h

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/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2012 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __DataStream_H__
#define __DataStream_H__

#include "OgrePrerequisites.h"
#include "OgreString.h"
#include "OgreSharedPtr.h"
#include <istream>

namespace Ogre {
    
    template <size_t cacheSize>
    class StaticCache
    {
    protected:
        char mBuffer[cacheSize];
        
        size_t mValidBytes;
        size_t mPos;
        
    public:
        StaticCache()
        {
            mValidBytes = 0;
            mPos = 0;
        }
        
        size_t cacheData(const void* buf, size_t count)
        {
            assert(avail() == 0 && "It is assumed that you cache data only after you have read everything.");
            
            if (count < cacheSize)
            {
                // number of bytes written is less than total size of cache
                if (count + mValidBytes <= cacheSize)
                {
                    // just append
                    memcpy(mBuffer + mValidBytes, buf, count);
                    mValidBytes += count;
                }
                else
                {
                    size_t begOff = count - (cacheSize - mValidBytes);
                    // override old cache content in the beginning
                    memmove(mBuffer, mBuffer + begOff, mValidBytes - begOff);
                    // append new data
                    memcpy(mBuffer + cacheSize - count, buf, count);
                    mValidBytes = cacheSize;
                }
                mPos = mValidBytes;
                return count;
            }
            else
            {
                // discard all
                memcpy(mBuffer, (const char*)buf + count - cacheSize, cacheSize);
                mValidBytes = mPos = cacheSize;
                return cacheSize;
            }
        }
        size_t read(void* buf, size_t count)
        {
            size_t rb = avail();
            rb = (rb < count) ? rb : count;
            memcpy(buf, mBuffer + mPos, rb);
            mPos += rb;
            return rb;
        }
        
        bool rewind(size_t count)
        {
            if (mPos < count)
            {
                clear();
                return false;
            }
            else
            {
                mPos -= count;
                return true;
            }
        }
        bool ff(size_t count)
        {
            if (avail() < count)
            {
                clear();
                return false;
            }
            else
            {
                mPos += count;
                return true;
            }
        }
        
        size_t avail() const
        {
            return mValidBytes - mPos;
        }
        
        void clear()
        {
            mValidBytes = 0;
            mPos = 0;
        }
    };
    
    
    class _OgreExport DataStream : public StreamAlloc
    {
    public:
        enum AccessMode
        {
            READ = 1, 
            WRITE = 2
        };
    protected:
        String mName;       
        size_t mSize;
        uint16 mAccess;

        #define OGRE_STREAM_TEMP_SIZE 128
    public:
        DataStream(uint16 accessMode = READ) : mSize(0), mAccess(accessMode) {}
        DataStream(const String& name, uint16 accessMode = READ) 
            : mName(name), mSize(0), mAccess(accessMode) {}
        const String& getName(void) { return mName; }
        uint16 getAccessMode() const { return mAccess; }
        virtual bool isReadable() const { return (mAccess & READ) != 0; }
        virtual bool isWriteable() const { return (mAccess & WRITE) != 0; }
        virtual ~DataStream() {}
        // Streaming operators
        template<typename T> DataStream& operator>>(T& val);
        virtual size_t read(void* buf, size_t count) = 0;
        virtual size_t write(const void* buf, size_t count)
        {
                        (void)buf;
                        (void)count;
            // default to not supported
            return 0;
        }

        virtual size_t readLine(char* buf, size_t maxCount, const String& delim = "\n");
        
        virtual String getLine( bool trimAfter = true );

        virtual String getAsString(void);

        virtual size_t skipLine(const String& delim = "\n");

        virtual void skip(long count) = 0;
    
        virtual void seek( size_t pos ) = 0;
        
        virtual size_t tell(void) const = 0;

        virtual bool eof(void) const = 0;

        size_t size(void) const { return mSize; }

        virtual void close(void) = 0;
        

    };

    typedef SharedPtr<DataStream> DataStreamPtr;

    typedef list<DataStreamPtr>::type DataStreamList;
    typedef SharedPtr<DataStreamList> DataStreamListPtr;

    class _OgreExport MemoryDataStream : public DataStream
    {
    protected:
        uchar* mData;
        uchar* mPos;
        uchar* mEnd;
        bool mFreeOnClose;          
    public:
        
        MemoryDataStream(void* pMem, size_t size, bool freeOnClose = false, bool readOnly = false);
        
        MemoryDataStream(const String& name, void* pMem, size_t size, 
                bool freeOnClose = false, bool readOnly = false);

        MemoryDataStream(DataStream& sourceStream, 
                bool freeOnClose = true, bool readOnly = false);
        
        MemoryDataStream(DataStreamPtr& sourceStream, 
                bool freeOnClose = true, bool readOnly = false);

        MemoryDataStream(const String& name, DataStream& sourceStream, 
                bool freeOnClose = true, bool readOnly = false);

        MemoryDataStream(const String& name, const DataStreamPtr& sourceStream, 
            bool freeOnClose = true, bool readOnly = false);

        MemoryDataStream(size_t size, bool freeOnClose = true, bool readOnly = false);
        MemoryDataStream(const String& name, size_t size, 
                bool freeOnClose = true, bool readOnly = false);

        ~MemoryDataStream();

        uchar* getPtr(void) { return mData; }
        
        uchar* getCurrentPtr(void) { return mPos; }
        
        size_t read(void* buf, size_t count);

        size_t write(const void* buf, size_t count);

        size_t readLine(char* buf, size_t maxCount, const String& delim = "\n");
        
        size_t skipLine(const String& delim = "\n");

        void skip(long count);
    
        void seek( size_t pos );
        
        size_t tell(void) const;

        bool eof(void) const;

        void close(void);

        void setFreeOnClose(bool free) { mFreeOnClose = free; }
    };

    typedef SharedPtr<MemoryDataStream> MemoryDataStreamPtr;

    class _OgreExport FileStreamDataStream : public DataStream
    {
    protected:
        std::istream* mInStream;
        std::ifstream* mFStreamRO;
        std::fstream* mFStream;
        bool mFreeOnClose;  

        void determineAccess();
    public:
        FileStreamDataStream(std::ifstream* s, 
            bool freeOnClose = true);
        FileStreamDataStream(std::fstream* s, 
            bool freeOnClose = true);

        FileStreamDataStream(const String& name, 
            std::ifstream* s, 
            bool freeOnClose = true);

        FileStreamDataStream(const String& name, 
            std::fstream* s, 
            bool freeOnClose = true);

        FileStreamDataStream(const String& name, 
            std::ifstream* s, 
            size_t size, 
            bool freeOnClose = true);

        FileStreamDataStream(const String& name, 
            std::fstream* s, 
            size_t size, 
            bool freeOnClose = true);

        ~FileStreamDataStream();

        size_t read(void* buf, size_t count);

        size_t write(const void* buf, size_t count);

        size_t readLine(char* buf, size_t maxCount, const String& delim = "\n");
        
        void skip(long count);
    
        void seek( size_t pos );

        size_t tell(void) const;

        bool eof(void) const;

        void close(void);
        
        
    };

    class _OgreExport FileHandleDataStream : public DataStream
    {
    protected:
        FILE* mFileHandle;
    public:
        FileHandleDataStream(FILE* handle, uint16 accessMode = READ);
        FileHandleDataStream(const String& name, FILE* handle, uint16 accessMode = READ);
        ~FileHandleDataStream();

        size_t read(void* buf, size_t count);

        size_t write(const void* buf, size_t count);

        void skip(long count);
    
        void seek( size_t pos );

        size_t tell(void) const;

        bool eof(void) const;

        void close(void);

    };
}
#endif