**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.373 2008/06/05 16:47:39 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    if( r>=iStart && r<=iEnd ){
      pParse->aColCache[i].affChange = 1;
    }
  }
}

/*
** Generate code to moves content from one register to another.
** Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo){
  int i;
  if( iFrom==iTo ) return;
  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Move, iFrom, iTo);
  for(i=0; i<pParse->nColCache; i++){
    if( pParse->aColCache[i].iReg==iFrom ){

      pParse->aColCache[i].iReg = iTo;
    }
  }
}

/*
** Return true if any register in the range iFrom..iTo (inclusive)
** is used as part of the column cache.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.374 2008/06/22 12:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
    if( r>=iStart && r<=iEnd ){
      pParse->aColCache[i].affChange = 1;
    }
  }
}

/*
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
  int i;
  if( iFrom==iTo ) return;
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
  for(i=0; i<pParse->nColCache; i++){
    int x = pParse->aColCache[i].iReg;
    if( x>=iFrom && x<iFrom+nReg ){
      pParse->aColCache[i].iReg += iTo-iFrom;
    }
  }
}

/*
** Return true if any register in the range iFrom..iTo (inclusive)
** is used as part of the column cache.

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** $Id: fault.c,v 1.9 2008/06/20 14:59:51 danielk1977 Exp $
*/

/*
** This file contains code to support the concept of "benign" 
** malloc failures (when the xMalloc() or xRealloc() method of the
** sqlite3_mem_methods structure fails to allocate a block of memory
** and returns 0). 
................................................................................
void sqlite3EndBenignMalloc(void){
  if( hooks.xBenignEnd ){
    hooks.xBenignEnd();
  }
}

#endif   /* #ifndef SQLITE_OMIT_BUILTIN_TEST */

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** $Id: fault.c,v 1.10 2008/06/22 12:37:58 drh Exp $
*/

/*
** This file contains code to support the concept of "benign" 
** malloc failures (when the xMalloc() or xRealloc() method of the
** sqlite3_mem_methods structure fails to allocate a block of memory
** and returns 0). 
................................................................................
void sqlite3EndBenignMalloc(void){
  if( hooks.xBenignEnd ){
    hooks.xBenignEnd();
  }
}

#endif   /* #ifndef SQLITE_OMIT_BUILTIN_TEST */

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.179 2008/06/05 11:39:11 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)
................................................................................
      /* Do the b-tree integrity checks */
      sqlite3VdbeAddOp3(v, OP_IntegrityCk, 2, cnt, 1);
      sqlite3VdbeChangeP5(v, i);
      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2);
      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zName),
         P4_DYNAMIC);
      sqlite3VdbeAddOp2(v, OP_Move, 2, 4);
      sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 2);
      sqlite3VdbeAddOp2(v, OP_ResultRow, 2, 1);
      sqlite3VdbeJumpHere(v, addr);

      /* Make sure all the indices are constructed correctly.
      */
      for(x=sqliteHashFirst(pTbls); x && !isQuick; x=sqliteHashNext(x)){

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the PRAGMA command.
**
** $Id: pragma.c,v 1.180 2008/06/22 12:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/* Ignore this whole file if pragmas are disabled
*/
#if !defined(SQLITE_OMIT_PRAGMA) && !defined(SQLITE_OMIT_PARSER)
................................................................................
      /* Do the b-tree integrity checks */
      sqlite3VdbeAddOp3(v, OP_IntegrityCk, 2, cnt, 1);
      sqlite3VdbeChangeP5(v, i);
      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2);
      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zName),
         P4_DYNAMIC);
      sqlite3VdbeAddOp3(v, OP_Move, 2, 4, 1);
      sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 2);
      sqlite3VdbeAddOp2(v, OP_ResultRow, 2, 1);
      sqlite3VdbeJumpHere(v, addr);

      /* Make sure all the indices are constructed correctly.
      */
      for(x=sqliteHashFirst(pTbls); x && !isQuick; x=sqliteHashNext(x)){

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.432 2008/06/20 18:13:25 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
){
  Vdbe *v = pParse->pVdbe;
  int nExpr = pOrderBy->nExpr;
  int regBase = sqlite3GetTempRange(pParse, nExpr+2);
  int regRecord = sqlite3GetTempReg(pParse);
  sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
  if( pSelect->iLimit>=0 ){
    int addr1, addr2;
    int iLimit;
................................................................................
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nColumn==1 );
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p, regResult);
      }else{
        sqlite3ExprCodeMove(pParse, regResult, iParm);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
................................................................................
      sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
      sqlite3VdbeJumpHere(v, j1);
      break;
    }
    case SRT_Mem: {
      assert( nColumn==1 );
      sqlite3ExprCodeMove(pParse, regRow, iParm);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }
#endif
    case SRT_Callback:
    case SRT_Coroutine: {
      int i;
................................................................................
  return 0;
}

/*
** Analyze and ORDER BY or GROUP BY clause in a SELECT statement.  Return
** the number of errors seen.
**
** The processing depends on whether the SELECT is simple or compound.
** For a simple SELECT statement, evry term of the ORDER BY or GROUP BY
** clause needs to be an expression.  If any expression is an integer
** constant, then that expression is replaced by the corresponding 
** expression from the result set.
**
** For compound SELECT statements, every expression needs to be of
** type TK_COLUMN with a iTable value as given in the 4th parameter.
** If any expression is an integer, that becomes the column number.
** Otherwise, match the expression against result set columns from
** the left-most SELECT.
*/
static int processCompoundOrderBy(
................................................................................
  }
  if( pRet==0 ){
    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
  }
  return pRet;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */










#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine is called to process a compound query form from
** two or more separate queries using UNION, UNION ALL, EXCEPT, or
** INTERSECT
**
................................................................................
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */
  ExprList *pOrderBy;   /* The ORDER BY clause on p */
  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
  SelectDest dest;      /* Alternative data destination */

  dest = *pDest;

  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  if( p==0 || p->pPrior==0 ){
    rc = 1;
    goto multi_select_end;
  }
................................................................................
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    rc = 1;
    goto multi_select_end;
  }







  /* Create the destination temporary table if necessary
  */

  if( dest.eDest==SRT_EphemTab ){
    assert( p->pEList );
    assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
    aSetP2[nSetP2++] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, 0);
    dest.eDest = SRT_Table;
  }

................................................................................

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
























































































































































































































































































































































#ifndef SQLITE_OMIT_VIEW
/* Forward Declarations */
static void substExprList(sqlite3*, ExprList*, int, ExprList*);
static void substSelect(sqlite3*, Select *, int, ExprList *);

/*
................................................................................
          sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
        }
      }
      sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
                          (char*)pKeyInfo, P4_KEYINFO_STATIC);
      j1 = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);

      /* Generate code that runs whenever the GROUP BY changes.
      ** Changes in the GROUP BY are detected by the previous code
      ** block.  If there were no changes, this block is skipped.
      **
      ** This code copies current group by terms in b0,b1,b2,...
      ** over to a0,a1,a2.  It then calls the output subroutine
      ** and resets the aggregate accumulator registers in preparation
      ** for the next GROUP BY batch.
      */
      for(j=0; j<pGroupBy->nExpr; j++){
        sqlite3ExprCodeMove(pParse, iBMem+j, iAMem+j);
      }
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
      VdbeComment((v, "output one row"));
      sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
      VdbeComment((v, "check abort flag"));
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      VdbeComment((v, "reset accumulator"));

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.433 2008/06/22 12:37:58 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
){
  Vdbe *v = pParse->pVdbe;
  int nExpr = pOrderBy->nExpr;
  int regBase = sqlite3GetTempRange(pParse, nExpr+2);
  int regRecord = sqlite3GetTempReg(pParse);
  sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
  if( pSelect->iLimit>=0 ){
    int addr1, addr2;
    int iLimit;
................................................................................
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nColumn==1 );
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p, regResult);
      }else{
        sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
................................................................................
      sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
      sqlite3VdbeJumpHere(v, j1);
      break;
    }
    case SRT_Mem: {
      assert( nColumn==1 );
      sqlite3ExprCodeMove(pParse, regRow, iParm, 1);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }
#endif
    case SRT_Callback:
    case SRT_Coroutine: {
      int i;
................................................................................
  return 0;
}

/*
** Analyze and ORDER BY or GROUP BY clause in a SELECT statement.  Return
** the number of errors seen.
**






** For compound SELECT statements, every expression needs to be of
** type TK_COLUMN with a iTable value as given in the 4th parameter.
** If any expression is an integer, that becomes the column number.
** Otherwise, match the expression against result set columns from
** the left-most SELECT.
*/
static int processCompoundOrderBy(
................................................................................
  }
  if( pRet==0 ){
    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
  }
  return pRet;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

/* Forward reference */
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest,    /* What to do with query results */
  char *aff             /* If eDest is SRT_Union, the affinity string */
);


#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine is called to process a compound query form from
** two or more separate queries using UNION, UNION ALL, EXCEPT, or
** INTERSECT
**
................................................................................
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */
  ExprList *pOrderBy;   /* The ORDER BY clause on p */
  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
  SelectDest dest;      /* Alternative data destination */



  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  if( p==0 || p->pPrior==0 ){
    rc = 1;
    goto multi_select_end;
  }
................................................................................
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    rc = 1;
    goto multi_select_end;
  }

#if 0
  if( p->pOrderBy ){
    return multiSelectOrderBy(pParse, p, pDest, aff);
  }
#endif

  /* Create the destination temporary table if necessary
  */
  dest = *pDest;
  if( dest.eDest==SRT_EphemTab ){
    assert( p->pEList );
    assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
    aSetP2[nSetP2++] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iParm, 0);
    dest.eDest = SRT_Table;
  }

................................................................................

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

#if 0 /****** ################ ******/
/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
*/
static int outputSubroutine(
  Parse *pParse,
  SelectDest *pIn
  SelectDest *pDest
){
  Vdbe *v = pParse->pVdbe;
  if( v==0 ) return;

  if( pDest->iMem==0 ){
    pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
    pDest->nMem = nResultCol;
  }

  switch( pDest->eDest ){
    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_EphemTab: {
      int r1 = sqlite3GetTempReg(pParse);
      int r2 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
      sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
      sqlite3ReleaseTempReg(pParse, r2);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      int addr2, r1;
      assert( nColumn==1 );
      addr2 = sqlite3VdbeAddOp1(v, OP_IsNull, regResult);
      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affinity);
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, 1, r1, &p->affinity, 1);
      sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      sqlite3VdbeJumpHere(v, addr2);
      break;
    }

    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nColumn==1 );
      sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
      /* The LIMIT clause will jump out of the loop for us */
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
    ** case of a subroutine, the subroutine itself is responsible for
    ** popping the data from the stack.
    */
    case SRT_Coroutine:
    case SRT_Callback: {
      if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->regCoroutine);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
      }
      break;
    }

#if !defined(SQLITE_OMIT_TRIGGER)
    /* Discard the results.  This is used for SELECT statements inside
    ** the body of a TRIGGER.  The purpose of such selects is to call
    ** user-defined functions that have side effects.  We do not care
    ** about the actual results of the select.
    */
    default: {
      break;
    }
#endif
  }
}

/*
** Alternative compound select code generator for cases when there
** is an ORDER BY clause.
**
** We assume a query of the following form:
**
**      <selectA>  <operator>  <selectB>  ORDER BY <orderbylist>
**
** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT.  The idea
** is to code both <selectA> and <selectB> with the ORDER BY clause as
** co-routines.  Then run the co-routines in parallel and merge the results
** into the output.  In addition to the two coroutines (called selectA and
** selectB) there are 7 subroutines:
**
**    outA:    Move the output of the selectA coroutine into the output
**             of the compound query.
**
**    outB:    Move the output of the selectB coroutine into the output
**             of the compound query.  (Only generated for UNION and
**             UNION ALL.  EXCEPT and INSERTSECT never output a row that
**             appears only in B.)
**
**    AltB:    Called when there is data from both coroutines and A<B.
**
**    AeqB:    Called when there is data from both coroutines and A==B.
**
**    AgtB:    Called when there is data from both coroutines and A>B.
**
**    EofA:    Called when data is exhausted from selectA.
**
**    EofB:    Called when data is exhausted from selectB.
**
** The implementation of the latter five subroutines depend on which 
** <operator> is used:
**
**
**             UNION ALL         UNION            EXCEPT          INTERSECT
**          -------------  -----------------  --------------  -----------------
**   AltB:   outA, nextA      outA, nextA       outA, nextA        nextA
**
**   AeqB:   outA, nextA         nextA             nextA           outA
**                                                            nextA while A==B
**
**   AgtB:   outB, nextB      outB, nextB          nextB           nextB
**
**   EofA:   outB, nextB      A<-B, outB,          halt            halt
**                          nextB while A==B
**
**   EofB:   outA, nextA      B<-A, outA        outA, nextA        halt
**                          nextA while A==B
**
** The implementation plan is to implement the two coroutines and seven
** subroutines first, then put the control logic at the bottom.  Like this:
**
**          goto Init
**     coA: coroutine for left query (A)
**     coB: coroutine for right query (B)
**    outA: output one row of A
**    outB: output one row of B (UNION and UNION ALL only)
**    EofA: ...
**    EofB: ...
**    AltB: ...
**    AeqB: ...
**    AgtB: ...
**    Init: initialize coroutine registers
**          yield coA
**          if eof(A) goto EofA
**          yield coB
**          if eof(B) goto EofB
**    Cmpr: Compare A, B
**          Jump AltB, AeqB, AgtB
**     End: ...
**
** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
** actually called using Gosub and they do not Return.  EofA and EofB loop
** until all data is exhausted then jump to the "end" labe.  AltB, AeqB,
** and AgtB jump to either L2 or to one of EofA or EofB.
*/
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest,    /* What to do with query results */
  char *aff             /* If eDest is SRT_Union, the affinity string */
){
  int rc = SQLITE_OK;   /* Success code from a subroutine */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */
  ExprList *pOrderBy;   /* The ORDER BY clause on p */
  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;
  int regEofA;
  int regAddrB;
  int regEofB;
  int addrSelectA;
  int addrSelectB;
  int regOutA;
  int regOutB;
  int addrOutA;
  int addrOutB;
  int addrEofA;
  int addrEofB;
  int addrAltB;
  int addrAeqB;
  int addrAgtB;
  int labelCmpr;
  int labelEnd;
  int j1, j2, j3;
  
  /* Patch up the ORDER BY clause */

  pPrior = p->pPrior;
  regAddrA = ++pParse->nMem;
  regEofA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regEofB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);

  j1 = sqlite3VdbeAddOp0(v, OP_Goto);
  addrSelectA = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for left SELECT"));
  sqlite3SelectDestInit(&destA, SRT_Coroutine, 0);
  sqlite3Select();
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA);
  VdbeNoopComment((v, "End coroutine for left SELECT"));

  addrSelectB = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for right SELECT"));
  sqlite3SelectDestInit(&destB, SRT_Coroutine, 0);
  sqlite3Select();
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB);
  VdbeNoopComment((v, "End coroutine for right SELECT"));

  VdbeNoopComment((v, "Output routine for A"));
  addrOutA = outputSubroutine(pParse, &destA, pDest);
  
  VdbeNoopComment((v, "Output routine for B"));
  addrOutB = outputSubroutine(pParse, &destB, pDest);

  if( op==TK_EXCEPT || op==TK_INTERSECT ){
    addrEofA = iEnd;
  }else{  
    VdbeNoopCommment((v, "eof-A subroutine"));
    addrEofA = sqlite3VdbeCurrentAddr(v);
    if( op==TK_ALL ){
      j2 = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
    }else{
      assert( op==TK_UNION );
      sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
      sqlite3ExprCodeMove(pParse, destB.iMem, destA.iMem, destB.nMem);
      j2 = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
      sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
      sqlite3VdbeAddOp3(v, OP_Compare, destA.iMem, destB.iMem, destB.nMem);
      sqlite3VdbeAddOp3(v, OP_Jump, j2, j2+1, j2);
    }
  }


  if( op==TK_INTERSECT ){
    addrEofA = iEnd;
  }else{  
    VdbeNoopCommment((v, "eof-B subroutine"));
    addrEofA = sqlite3VdbeCurrentAddr(v);
    if( op==TK_ALL || op==TK_EXCEPT ){
      j2 = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
    }else{
      assert( op==TK_UNION );
      sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3ExprCodeMove(pParse, destA.iMem, destB.iMem, destA.nMem);
      j2 = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
      sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3VdbeAddOp3(v, OP_Compare, destA.iMem, destB.iMem, destB.nMem);
      sqlite3VdbeAddOp3(v, OP_Jump, j2, j2+1, j2);
    }
  }

  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeCurrentAddr(v);
  if( op!=TK_INTERSECT ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
  }
  addrAeqB = sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCompare);

  if( op==TK_ALL ){
    addrAeqB = addrAltB;
  }else if( op==TK_INTERSECT ){
    VdbeNoopComment((v, "A-eq-B subroutine"));
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
    j2 = sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
    sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
    sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destA.iMem,
                         pKeyInfo, P4_KEYINFO_STATIC);
    j3 = sqlite3VdbeCurrentAddr(v)+1;
    sqlite3VdbeAddOp3(v, OP_Jump, j3, j2, j3);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCompare);
  }

  VdbeNoopComment((v, "A-gt-B subroutine"));
  addrAgtB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_ALL || op==TK_UNION ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
  }
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCompare);

  sqlite3VdbeJumpHere(v, j1);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
  sqlite3VdbeAddOp2(v, OP_Integer, addrSelectA, regAddrA);
  sqlite3VdbeAddOp2(v, OP_Integer, addrSelectB, regAddrB);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
  sqlite3VdbeResolve(v, labelCompare);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destA.iMem,
                         pKeyInfo, P4_KEYINFO_HANDOFF);
  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
  sqlite3VdbeResolveLabel(v, labelEnd);
  
}
#endif /***** ########### *****/

#ifndef SQLITE_OMIT_VIEW
/* Forward Declarations */
static void substExprList(sqlite3*, ExprList*, int, ExprList*);
static void substSelect(sqlite3*, Select *, int, ExprList *);

/*
................................................................................
          sqlite3VdbeAddOp3(v, OP_Column, sAggInfo.sortingIdx, j, iBMem+j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
        }
      }
      sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
                          (char*)pKeyInfo, P4_KEYINFO);
      j1 = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);

      /* Generate code that runs whenever the GROUP BY changes.
      ** Changes in the GROUP BY are detected by the previous code
      ** block.  If there were no changes, this block is skipped.
      **
      ** This code copies current group by terms in b0,b1,b2,...
      ** over to a0,a1,a2.  It then calls the output subroutine
      ** and resets the aggregate accumulator registers in preparation
      ** for the next GROUP BY batch.
      */

      sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);

      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
      VdbeComment((v, "output one row"));
      sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
      VdbeComment((v, "check abort flag"));
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      VdbeComment((v, "reset accumulator"));

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.721 2008/06/20 15:24:02 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
void sqlite3WhereEnd(WhereInfo*);
int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);
void sqlite3ExprCodeMove(Parse*, int, int);
void sqlite3ExprClearColumnCache(Parse*, int);
void sqlite3ExprCacheAffinityChange(Parse*, int, int);
int sqlite3ExprWritableRegister(Parse*,int,int);
void sqlite3ExprHardCopy(Parse*,int,int);
int sqlite3ExprCode(Parse*, Expr*, int);
int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
int sqlite3ExprCodeTarget(Parse*, Expr*, int);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.722 2008/06/22 12:37:58 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
void sqlite3WhereEnd(WhereInfo*);
int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);
void sqlite3ExprCodeMove(Parse*, int, int, int);
void sqlite3ExprClearColumnCache(Parse*, int);
void sqlite3ExprCacheAffinityChange(Parse*, int, int);
int sqlite3ExprWritableRegister(Parse*,int,int);
void sqlite3ExprHardCopy(Parse*,int,int);
int sqlite3ExprCode(Parse*, Expr*, int);
int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
int sqlite3ExprCodeTarget(Parse*, Expr*, int);

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** 
** $Id: test_mutex.c,v 1.3 2008/06/19 08:51:25 danielk1977 Exp $
*/

#include "tcl.h"
#include "sqlite3.h"
#include <stdlib.h>
#include <assert.h>
#include <string.h>
................................................................................
  int i;
  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
  }
  memset(&g, 0, sizeof(g));
  return SQLITE_OK;
}

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** 
** $Id: test_mutex.c,v 1.4 2008/06/22 12:37:58 drh Exp $
*/

#include "tcl.h"
#include "sqlite3.h"
#include <stdlib.h>
#include <assert.h>
#include <string.h>
................................................................................
  int i;
  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
  }
  memset(&g, 0, sizeof(g));
  return SQLITE_OK;
}

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.752 2008/06/20 18:13:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
  fprintf(out, "REG[%d] = ", iReg);
  memTracePrint(out, p);
  fprintf(out, "\n");
}
#endif

#ifdef SQLITE_DEBUG
#  define REGISTER_TRACE(R,M) if(p->trace&&R>0)registerTrace(p->trace,R,M)
#else
#  define REGISTER_TRACE(R,M)
#endif


#ifdef VDBE_PROFILE

................................................................................
    goto too_big;
  }
  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Move P1 P2 * * *
**
** Move the value in register P1 over into register P2.  Register P1

** is left holding a NULL.  It is an error for P1 and P2 to be the
** same register.

*/
case OP_Move: {
  char *zMalloc;



  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );

  pIn1 = &p->aMem[pOp->p1];
  REGISTER_TRACE(pOp->p1, pIn1);
  assert( pOp->p2>0 );
  assert( pOp->p2<=p->nMem );

  pOut = &p->aMem[pOp->p2];
  assert( pOut!=pIn1 );



  zMalloc = pOut->zMalloc;
  pOut->zMalloc = 0;
  sqlite3VdbeMemMove(pOut, pIn1);
  pIn1->zMalloc = zMalloc;
  REGISTER_TRACE(pOp->p2, pOut);



  break;
}

/* Opcode: Copy P1 P2 * * *
**
** Make a copy of register P1 into register P2.
**

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.753 2008/06/22 12:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
  fprintf(out, "REG[%d] = ", iReg);
  memTracePrint(out, p);
  fprintf(out, "\n");
}
#endif

#ifdef SQLITE_DEBUG
#  define REGISTER_TRACE(R,M) if(p->trace)registerTrace(p->trace,R,M)
#else
#  define REGISTER_TRACE(R,M)
#endif


#ifdef VDBE_PROFILE

................................................................................
    goto too_big;
  }
  sqlite3VdbeMemShallowCopy(pOut, &p->aVar[j], MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Move P1 P2 P3 * *
**
** Move the values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P1-1 are
** left holding a NULL.  It is an error for register ranges

** P1..P1+P3-1 and P2..P2+P3-1 to overlap.
*/
case OP_Move: {
  char *zMalloc;
  int n = pOp->p3;
  int p1 = pOp->p1;
  int p2 = pOp->p2;
  assert( n>0 );
  assert( p1>0 );
  assert( p1+n<p->nMem );
  pIn1 = &p->aMem[p1];

  assert( p2>0 );

  assert( p2+n<p->nMem );
  pOut = &p->aMem[p2];

  assert( p1+n<=p2 || p2+n<=p1 );
  while( n-- ){
    REGISTER_TRACE(p1++, pIn1);
    zMalloc = pOut->zMalloc;
    pOut->zMalloc = 0;
    sqlite3VdbeMemMove(pOut, pIn1);
    pIn1->zMalloc = zMalloc;
    REGISTER_TRACE(p2++, pOut);
    pIn1++;
    pOut++;
  }
  break;
}

/* Opcode: Copy P1 P2 * * *
**
** Make a copy of register P1 into register P2.
**

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.390 2008/06/20 18:13:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"



................................................................................
    int nField, nByte;

    nField = ((KeyInfo*)zP4)->nField;
    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
    pKeyInfo = sqlite3Malloc( nByte );
    pOp->p4.pKeyInfo = pKeyInfo;
    if( pKeyInfo ){

      memcpy(pKeyInfo, zP4, nByte);
      /* In the current implementation, P4_KEYINFO is only ever used on
      ** KeyInfo structures that have no aSortOrder component.  Elements
      ** with an aSortOrder always use P4_KEYINFO_HANDOFF.  So we do not
      ** need to bother with duplicating the aSortOrder. */
      assert( pKeyInfo->aSortOrder==0 );
#if 0
      aSortOrder = pKeyInfo->aSortOrder;
      if( aSortOrder ){
        pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
        memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
      }
#endif
      pOp->p4type = P4_KEYINFO;
    }else{
      p->db->mallocFailed = 1;
      pOp->p4type = P4_NOTUSED;
    }
  }else if( n==P4_KEYINFO_HANDOFF ){
    pOp->p4.p = (void*)zP4;

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.391 2008/06/22 12:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"



................................................................................
    int nField, nByte;

    nField = ((KeyInfo*)zP4)->nField;
    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]) + nField;
    pKeyInfo = sqlite3Malloc( nByte );
    pOp->p4.pKeyInfo = pKeyInfo;
    if( pKeyInfo ){
      u8 *aSortOrder;
      memcpy(pKeyInfo, zP4, nByte);






      aSortOrder = pKeyInfo->aSortOrder;
      if( aSortOrder ){
        pKeyInfo->aSortOrder = (unsigned char*)&pKeyInfo->aColl[nField];
        memcpy(pKeyInfo->aSortOrder, aSortOrder, nField);
      }

      pOp->p4type = P4_KEYINFO;
    }else{
      p->db->mallocFailed = 1;
      pOp->p4type = P4_NOTUSED;
    }
  }else if( n==P4_KEYINFO_HANDOFF ){
    pOp->p4.p = (void*)zP4;