core/sql/comexe/ComKeyRange.h

/**********************************************************************
// @@@ START COPYRIGHT @@@
//
// Licensed to the Apache Software Foundation (ASF) under one
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/* -*-C++-*-
****************************************************************************
*
* File:         ComKeyRange.h
* Description:  defines base classes for objects describing key ranges
*
* Created:      5/6/98
* Language:     C++
*
*
*
*
****************************************************************************
*/

#ifndef COMKEYRANGE_H
#define COMKEYRANGE_H

#include "NAVersionedObject.h"
#include "ExpCriDesc.h"
#include "ex_expr.h"

// forward references
class ex_cri_desc;
class ex_expr;
class keySingleSubsetGen;
class keyMdamGen;

/////////////////////////////////////////////////////////////////////////
//
// Class keyRangeGen
//
// This class contains compiler-generated information used by scan
// operators that can access ordered data directly.  It is a virtual
// class that defines a common interface for different types of key
// access.  The idea is to encapsulate the generation of key ranges.
//
//
/////////////////////////////////////////////////////////////////////////

class keyRangeGen : public NAVersionedObject
{
public:

  enum key_type { KEYSINGLESUBSET, // single key range
		  KEYMDAM };      // MDAM  

  enum { FILLER_LENGTH = 16 };
protected:

  ExCriDescPtr workCriDesc_;                // 00-07
  UInt32 keyLength_;                        // 08-11
  UInt16 keyValuesAtpIndex_;                // 12-13
  UInt16 excludeFlagAtpIndex_;              // 14-15
  UInt16 dataConvErrorFlagAtpIndex_;        // 16-17

private:

  Int16 keyType_;                           // 18-19

  // while accessing a SQL/MP index, the first 2 bytes of the key value 
  // used is the keytag value. This is a 'special' key column that
  // is not part of the base table or the key expressions that are
  // generated. If the keytag_ value is greater than 0, then the
  // first two bytes of the key row are initialized with it in
  // getNextKeyRange() method. The keytag_ value is set by the generator
  // when key info is generated.
  UInt16 keytag_;                           // 20-21

  UInt16 flags_;                            // 22-23

  char fillersKeyRangeGen_[16];             // 24-39
public:

  // default constructor needed by UNPACK
  keyRangeGen()
   : NAVersionedObject(-1)
  {}

  keyRangeGen(key_type keyType,
		    ULng32 keyLen,
		    ex_cri_desc * workCriDesc,
		    unsigned short keyValuesAtpIndex,
		    unsigned short excludeFlagAtpIndex,
		    unsigned short dataConvErrorFlagAtpIndex);

  virtual ~keyRangeGen() { };

  // ---------------------------------------------------------------------
  // Redefine virtual functions required for Versioning.
  //----------------------------------------------------------------------
  virtual char *findVTblPtr(short classID);

  virtual unsigned char getClassVersionID()
  {
    return 1;
  }

  virtual void populateImageVersionIDArray()
  {
    setImageVersionID(0,getClassVersionID());
  }

  virtual short getClassSize()
                                     { return (short)sizeof(keyRangeGen); }

  virtual keySingleSubsetGen * castToKeySingleSubsetGen() { return NULL; }
  virtual keyMdamGen * castToKeyMdamGen() { return NULL; }

  // for UNPACK
  void fixupVTblPtr(); 
 
  // accessor functions
  key_type getType() { return (key_type) keyType_; };

  ULng32 getKeyLength() const
  { return keyLength_; };
  ex_cri_desc * getWorkCriDesc() const
  { return workCriDesc_; };
  unsigned short getKeyValuesAtpIndex() const
  { return keyValuesAtpIndex_; };
  unsigned short getExcludeFlagAtpIndex() const
  { return excludeFlagAtpIndex_; };
  unsigned short getDataConvErrorFlagAtpIndex() const
  { return dataConvErrorFlagAtpIndex_; };

  UInt16 getKeytag() const
    { return keytag_; };
  void setKeytag(UInt16 kt)
    { keytag_ = kt; };

  virtual Long pack(void *);
  virtual Lng32 unpack(void *, void * reallocator);

  virtual ex_expr* getExpressionNode(Int32 pos)  { return NULL; }
    
};

// ---------------------------------------------------------------------
// Template instantiation to produce a 64-bit pointer emulator class
// for keyRangeGen
// ---------------------------------------------------------------------
typedef NAVersionedObjectPtrTempl<keyRangeGen> keyRangeGenPtr;


#endif