core/sql/refresh/RuSQLComposer.h

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#ifndef _RU_SQL_COMPOSER_H_
#define _RU_SQL_COMPOSER_H_

/* -*-C++-*-
******************************************************************************
*
* File:         RuSQLComposer.h
* Description:  Definition of class CRUSQLComposer
*				
*
* Created:      08/13/2000
* Language:     C++
* 
*
* 
******************************************************************************
*/

//--------------------------------------------------------------------------//
//	CRUSQLComposer
//	
//	This is an abstract class for all sql composers classes.
//	Each Composer may have its own compose functions. After composing a 
//	statement the user may retrieve the sql text by calling GetSql().
//
//	The class also implements some service functions (like transalating 
//	numbers into strings, using special sql syntax etc.).
//
//--------------------------------------------------------------------------//

#include "refresh.h"
#include "dsstring.h"

#include "RuException.h"

class CRUTask;

class REFRESH_LIB_CLASS CRUSQLComposer {

	//----------------------------------//
	//	Public Members
	//----------------------------------//
public:
	CRUSQLComposer() : sql_("") {}
	virtual ~CRUSQLComposer() {}

public:
	// Retrieve the text generated by the last call to ComposeXXX()
	const CDSString &GetSQL() const 
	{ 
		return sql_; 
	}

	static CDSString TInt32ToStr(TInt32 num);
	static CDSString TInt64ToStr(TInt64 src);
	static CDSString TInt64ToTwoStrs(TInt64 num);

	// Return a string that represent a cast expression for execution param
	static CDSString ComposeCastExpr(const CDSString &type);
	
	// Add a prefix/suffix to a (possibly quoted) identifier string.
	// Take care to leave the quotes in place, if there are ones
	static void AddPrefixToString(const CDSString &prefix, CDSString &to);
	static void AddSuffixToString(const CDSString &suffix, CDSString &to);

	// Returns the name as a quoted name with the given prefix
	static CDSString ComposeQuotedColName(
		const CDSString &prefix,
		const CDSString &name);

	//----------------------------------//
	//	Protected Members
	//----------------------------------//
protected:
	// Text generated by the last call to ComposeXXX()
	// A temporary buffer to hold the generated SQL
	// Since this data member is used VERY often, it is defined as protected.
	CDSString sql_;

	//----------------------------------//
	//	Private Members
	//----------------------------------//
private:
	//-- Prevent copying
	CRUSQLComposer(const CRUSQLComposer &other);
	CRUSQLComposer &operator = (const CRUSQLComposer &other);
};

//--------------------------------------------------------------------------//
//	The inliners
//--------------------------------------------------------------------------//

inline CDSString CRUSQLComposer::TInt32ToStr(TInt32 num)
{
	char buf[20];
	sprintf(buf, "%d", num);
	return CDSString(buf);
}

//--------------------------------------------------------------------------//

inline CDSString CRUSQLComposer::TInt64ToStr(TInt64 src)
{
  const Int32 maxBufferSize = 50;

  TInt64 temp = src;  // (src >= 0) ? src : - src;
  char buffer[maxBufferSize];
  char *s = &buffer[maxBufferSize];
  *--s = '\0';
  do 
  {
#ifdef NA_NSK
    Int32 c = (Int32) (temp % 10);
#else
    char c = (char) (temp % 10);
#endif // NA_NSK
    if (c < 0)
	{
      c = -c;
	}
    *--s = (char)(c + '0');
    temp /= 10;
  } while (temp != 0);
  if (src < 0)
  {
    *--s = '-';
  }
  return CDSString(s);
}

//--------------------------------------------------------------------------//

inline CDSString CRUSQLComposer::TInt64ToTwoStrs(TInt64 num)
{
	const Int32 maxBufferSize = 50;
	char buf[maxBufferSize];

	// Break a quad-word into two double-words
	TInt32 msw, lsw;
	msw = (TInt32) (num >> 32);
	lsw = (TInt32) (num - ((TInt64)msw << 32));

	sprintf(buf, "%d %d", msw,lsw);

	return CDSString(buf);
}

//--------------------------------------------------------------------------//

inline CDSString CRUSQLComposer::ComposeCastExpr(const CDSString &type)
{
	return "CAST (? AS " + type + ")";
}

//--------------------------------------------------------------------------//

inline
CDSString CRUSQLComposer::ComposeQuotedColName(const CDSString &prefix,
											   const CDSString &name)
{
	CDSString rtn(name);

	AddPrefixToString(prefix, rtn);
	
	if ('"' != rtn.operator[](0))
	{
		// The string is not quoted yet...
		rtn = "\"" + rtn + "\""; 
	}

	return rtn;
}

//--------------------------------------------------------------------------//

inline 
void CRUSQLComposer::AddPrefixToString(const CDSString &prefix, CDSString &to)
{
	char firstchar = to.operator[](0);
	if ('"' == firstchar)
	{
		// A delimited identifier. Remove the leading '"'.
		to.Remove(0, 1);
		// And complement it at the beginning
		to = "\"" + prefix + to;
	}
	else
	{
		to = prefix + to;
	}
}

//--------------------------------------------------------------------------//

inline 
void CRUSQLComposer::AddSuffixToString(const CDSString &suffix, CDSString &to)
{
 Lng32 len = to.GetLength();
	RUASSERT(len>0);
	
	char lastchar = to.operator[](len-1);
	if ('"' == lastchar)
	{
		// A delimited identifier. Remove the trailing '"'.
		to.Remove(len-1, 1);
		// And complement it at the end
		to += suffix + "\"";
	}
	else
	{
		to += suffix;
	}
}

#endif