/*
** This function is similar to sqlite3ExprDup(), except that if pzBuffer
** is not NULL then *pzBuffer is assumed to point to a buffer large enough
** to store the copy of expression p, the copies of p->u.zToken
** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
** if any. Before returning, *pzBuffer is set to the first byte passed the
** portion of the buffer copied into by this function.
*/
static Expr exprDup( sqlite3 db, Expr p, int flags, ref Expr pzBuffer )
{
Expr pNew = null; /* Value to return */
if ( p != null )
{
bool isReduced = ( flags & EXPRDUP_REDUCE ) != 0;
Expr zAlloc = new Expr();
u32 staticFlag = 0;
Debug.Assert( pzBuffer == null || isReduced );
/* Figure out where to write the new Expr structure. */
//if ( pzBuffer !=null)
//{
// zAlloc = pzBuffer;
// staticFlag = EP_Static;
//}
//else
//{
// zAlloc = new Expr();//sqlite3DbMallocRaw( db, dupedExprSize( p, flags ) );
//}
pNew = p.Copy_Minimal();// (Expr*)zAlloc;
if ( pNew != null )
{
/* Set nNewSize to the size allocated for the structure pointed to
** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
** by the copy of the p->u.zToken string (if any).
*/
int nStructSize = dupedExprStructSize( p, flags );
int nNewSize = nStructSize & 0xfff;
int nToken;
if ( !ExprHasProperty( p, EP_IntValue ) && !String.IsNullOrEmpty( p.u.zToken ) )
{
nToken = sqlite3Strlen30( p.u.zToken );
}
else
{
nToken = 0;
}
if ( isReduced )
{
Debug.Assert( !ExprHasProperty( p, EP_Reduced ) );
//memcpy( zAlloc, p, nNewSize );
}
else
{
int nSize = exprStructSize( p );
//memcpy( zAlloc, p, nSize );
//memset( &zAlloc[nSize], 0, EXPR_FULLSIZE - nSize );
}
/* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
unchecked { pNew.flags &= (ushort)( ~( EP_Reduced | EP_TokenOnly | EP_Static ) ); }
pNew.flags |= (ushort)( nStructSize & ( EP_Reduced | EP_TokenOnly ) );
pNew.flags |= (ushort)staticFlag;
/* Copy the p->u.zToken string, if any. */
if ( nToken != 0 )
{
string zToken;// = pNew.u.zToken = (char*)&zAlloc[nNewSize];
zToken = p.u.zToken.Substring( 0, nToken );// memcpy( zToken, p.u.zToken, nToken );
}
if ( 0 == ( ( p.flags | pNew.flags ) & EP_TokenOnly ) )
{
/* Fill in the pNew.x.pSelect or pNew.x.pList member. */
if ( ExprHasProperty( p, EP_xIsSelect ) )
{
pNew.x.pSelect = sqlite3SelectDup( db, p.x.pSelect, isReduced ? 1 : 0 );
}
else
{
pNew.x.pList = sqlite3ExprListDup( db, p.x.pList, isReduced ? 1 : 0 );
}
}
/* Fill in pNew.pLeft and pNew.pRight. */
if ( ExprHasAnyProperty( pNew, EP_Reduced | EP_TokenOnly ) )
{
//zAlloc += dupedExprNodeSize( p, flags );
if ( ExprHasProperty( pNew, EP_Reduced ) )
{
pNew.pLeft = exprDup( db, p.pLeft, EXPRDUP_REDUCE, ref zAlloc );
pNew.pRight = exprDup( db, p.pRight, EXPRDUP_REDUCE, ref zAlloc );
}
if ( pzBuffer != null )
{
pzBuffer = zAlloc;
}
}
else
{
pNew.flags2 = 0;
if ( !ExprHasAnyProperty( p, EP_TokenOnly ) )
{
pNew.pLeft = sqlite3ExprDup( db, p.pLeft, 0 );
pNew.pRight = sqlite3ExprDup( db, p.pRight, 0 );
}
}
}
}
return pNew;
}