class c4_Strategy

A strategy encapsulates code dealing with file I/O and the system.

Public:

c4_Strategy (c4_File* file_ =0);

Constructs a new strategy object.

virtual ~c4_Strategy ();

virtual bool DataOpen (const char* fileName_, bool allowWriting_);

Opens a data file by name.

virtual void DataSeek (t4_i32 position_);

Sets file position.

virtual int DataRead (void* buffer_, int length_);

Reads a number of bytes.

virtual void DataLoad (void* buffer_, int length_);

Reads an exact number of bytes.

virtual void DataWrite (const void* buffer_, int length_);

Writes a number of bytes.

virtual void DataCommit (t4_i32 newSize_);

Flushes and truncate file.

virtual int StreamRead (void* auxArg_, void* buffer_, int length_);

Consumes some bytes sequentially.

virtual void StreamWrite (void* auxArg_, const void* buffer_, int length_);

Produces some bytes sequentially.

c4_ColCache* _colCache;

Holds a cache manager for all columns.

bool _keepAfterCommit;

Keep data in memory after each commit (default is false).

bool _bytesFlipped;

True if the storage format is not native (default is false).

const t4_byte* _mapStart;

First byte in file mapping, zero if not active.

const t4_byte* _mapLimit;

Past last byte in file mapping, zero if not active.

Protected:

c4_File* _file;

Pointer to file object.

#include "k4strat.h"   // Jun 8, 1997