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FBwBlob.h

/*
 * \file FBwBlob.h      
 * \brief Classes for Blob handling
*/


#ifndef FBwBLOBH
#define FBwBLOBH
#include <string>
#include <ibase.h>

namespace fbwrap {

#ifndef FBwDBH
class FBwDb;
class FBwTransaction;
#endif

class FBwBlobDesc
{
    FBwDb *db;
    ISC_BLOB_DESC bdesc;
    bool error;
public:

    FBwBlobDesc(FBwDb *pdb);
    // Blob description search
    bool Lookup(string Table,string column,FBwTransaction *mtr);
    short Subtype();
    short Charset();
    short GetSegLen();
    bool Error()
    {
        return error;
    }
};

class FBwBlob
{
    FBwDb *db;
    ISC_QUAD *blob_id;
    isc_blob_handle bhnd;
    FBwBlobDesc bdesc;
    FBwTransaction *mtr;
    int nSegLen;
    int nSeg;
    int nSize;
    char *SegBuf;
    int bufCapacity;
    struct {
        bool opened:1;
        bool reading:1;
        bool writing:1;
        bool eof:1;
        bool error:1;
    } stat;
    void ClearStat()
    {
        stat.opened=false;
        stat.reading=false;
        stat.writing=false;
        stat.eof=true;      //Attempts to read only succeed after opening
        stat.error=false;
    }
    bool NoInfoEnd(char p)
    {
        return p!= isc_info_end && p!= isc_info_truncated && p!= isc_info_error;
    }
protected:
    void AllocSegBuf();
    void GetBlobInfo();
public:

    FBwBlob(FBwDb *pdb);

    FBwBlob(FBwDb *pdb,string Tabla,string Columna);
    void WriteSegment(const char *buffer,int size);
    void Write(const string &value);
    int ReadSegment()
    {
        return ReadSegment(SegBuf,nSegLen);
    }

    int ReadSegment(char *buffer,int seglen);

    int Read(char *b, int len);
    int Size()
    {
        return nSize;
    }
    void SetDB(FBwDb *pdb)
    {
        if( IsOpened() )
            Close();
        db=pdb;
    }

    bool Open(ISC_QUAD *pblob_id);
    bool Rewind()
    {
        if( stat.writing )
            return false;
        if( IsOpened() )
            Close();
        Open(blob_id);
    }

    bool Create(ISC_QUAD *pblob_id);
    bool Close();
    bool Cancel();
    char *GetSegmentBuffer()
    {
        return SegBuf;
    }
    int GetSegmentLength()
    {
        return nSegLen;
    }

    bool IsOpened()
    {
        return stat.opened;
    }

    bool eof()
    {
        return stat.eof;
    }

    ISC_QUAD *GetBlobId()
    {
        return blob_id;
    }

    virtual ~FBwBlob();

    bool Error()
    {
        return stat.error;
    }
};

};  
#endif

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