SQLite

  sqlite3VdbeAddOp2(v, OP_Integer, 0, regZero);
  sqlite3VdbeAddOp2(v, OP_MustBeInt, reg, sqlite3VdbeCurrentAddr(v)+2);
  sqlite3VdbeAddOp3(v, OP_Ge, regZero, sqlite3VdbeCurrentAddr(v)+2, reg);
  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_ERROR, OE_Abort);
  sqlite3VdbeAppendP4(v, (void*)azErr[bEnd], P4_STATIC);
}

static void windowAggStep(
  Parse *pParse, 
  Window *pMWin, 
  int csr,
  int bInverse, 
  int reg
){
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    int i;
    for(i=0; i<pWin->nArg; i++){
      sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
    }
    sqlite3VdbeAddOp3(v, OP_AggStep0, bInverse, reg, pWin->regAccum);
    sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, (u8)pWin->nArg);
  }
}

/*
** ROWS BETWEEN <expr> PRECEDING    AND <expr> FOLLOWING
**
**   ...
**     if( new partition ){
**       Gosub flush_partition
**     }
**     Insert (record in eph-table)
**   sqlite3WhereEnd()
**   Gosub flush_partition
**
** flush_partition:
**   Once {
**     OpenDup (iEphCsr -> csrStart)
**     OpenDup (iEphCsr -> csrEnd)
**   }
**   regStart = <expr1>            // PRECEDING expression
**   regEnd = <expr2>          // FOLLOWING expression
**   if( regStart<0 || regEnd<0 ) throw exception!
**   Rewind (csr,csrStart,csrEnd)       // if EOF goto flush_partition_done
**     Aggstep (csrEnd)
**     Next(csrEnd)                     // if EOF fall-through
**     if( (regEnd--)<=0 ){
**       AggFinal (xValue)
**       Gosub addrGosub
**       Next(csr)                // if EOF goto flush_partition_done
**       if( (regStart--)<=0 ){
**         AggStep (csrStart, xInverse)
**         Next(csrStart)
**       }
**     }
** flush_partition_done:


**   ResetSorter (csr)
**   Return
**
** ROWS BETWEEN <expr> PRECEDING    AND CURRENT ROW
** ROWS BETWEEN CURRENT ROW         AND <expr> FOLLOWING
** ROWS BETWEEN <expr> PRECEDING    AND UNBOUNDED FOLLOWING
** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> FOLLOWING
**
**   These are similar to the above. For "CURRENT ROW", intialize the
**   register to 0. For "UNBOUNDED ..." to infinity.
**
** ROWS BETWEEN <expr> FOLLOWING    AND <expr> FOLLOWING
**
**   regEnd = regEnd - regStart
**   Rewind (csr,csrStart,csrEnd)   // if EOF goto flush_partition_done
**     Aggstep (csrEnd)
**     Next(csrEnd)                 // if EOF fall-through
**     if( (regEnd--)<=0 ){
**       AggStep (csrStart, xInverse)
**       Next (csrStart)
**       if( (regStart--)<=0 ){
**         AggFinal (xValue)
**         Gosub addrGosub
**         Next(csr)              // if EOF goto flush_partition_done
**       }
**     }
**
** ROWS BETWEEN <expr> PRECEDING    AND <expr> PRECEDING
**
**   Replace the bit after "Rewind" in the above with:
**
**     if( (regEnd--)<=0 ){
**       AggStep (csrEnd)
**       Next (csrEnd)
**     }
**     AggFinal (xValue)
**     Gosub addrGosub
**     Next(csr)                  // if EOF goto flush_partition_done
**     if( (regStart--)<=0 ){
**       AggStep (csr2, xInverse)
**       Next (csr2)
**     }
**
*/
static void windowCodeRowExprStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub
){
  Window *pMWin = p->pWin;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  int k;
  int iSubCsr = p->pSrc->a[0].iCursor;
  int nSub = p->pSrc->a[0].pTab->nCol;
  int regFlushPart;               /* Register for "Gosub flush_partition" */
  int lblFlushPart;               /* Label for "Gosub flush_partition" */
  int lblFlushDone;               /* Label for "Gosub flush_partition_done" */

  int reg = pParse->nMem+1;
  int regRecord = reg+nSub;
  int regRowid = regRecord+1;
  int addr;
  int csrStart = pParse->nTab++;
  int csrEnd = pParse->nTab++;
  int regStart;                    /* Value of <expr> PRECEDING */
  int regEnd;                      /* Value of <expr> FOLLOWING */
  int addrNext;
  int addrGoto;
  int addrTop;
  int addrIfPos1;
  int addrIfPos2;

  assert( pMWin->eStart==TK_PRECEDING 
       || pMWin->eStart==TK_CURRENT 
       || pMWin->eStart==TK_UNBOUNDED 
  );
  assert( pMWin->eEnd==TK_FOLLOWING 
       || pMWin->eEnd==TK_CURRENT 
       || pMWin->eEnd==TK_UNBOUNDED 
       || pMWin->eEnd==TK_PRECEDING 
  );

  pParse->nMem += nSub + 2;

  /* Allocate register and label for the "flush_partition" sub-routine. */
  regFlushPart = ++pParse->nMem;
  lblFlushPart = sqlite3VdbeMakeLabel(v);
  lblFlushDone = sqlite3VdbeMakeLabel(v);

  regStart = ++pParse->nMem;
  regEnd = ++pParse->nMem;

  /* Martial the row returned by the sub-select into an array of 
  ** registers. */
  for(k=0; k<nSub; k++){
    sqlite3VdbeAddOp3(v, OP_Column, iSubCsr, k, reg+k);
  }
  sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, nSub, regRecord);

  /* Check if this is the start of a new partition. If so, call the
  ** flush_partition sub-routine.  */
  if( pMWin->pPartition ){
    ExprList *pPart = pMWin->pPartition;
    int nPart = (pPart ? pPart->nExpr : 0);
    int addrJump = 0;
    int regNewPart = reg + pMWin->nBufferCol;
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);

    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart,nPart);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
    sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart);
  }

  /* Buffer the current row in the ephemeral table. */
  sqlite3VdbeAddOp2(v, OP_NewRowid, pMWin->iEphCsr, regRowid);
  sqlite3VdbeAddOp3(v, OP_Insert, pMWin->iEphCsr, regRecord, regRowid);

  /* End of the input loop */
  sqlite3WhereEnd(pWInfo);

  /* Invoke "flush_partition" to deal with the final (or only) partition */
  sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
  addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);

  /* flush_partition: */
  sqlite3VdbeResolveLabel(v, lblFlushPart);
  sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrStart, pMWin->iEphCsr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, csrEnd, pMWin->iEphCsr);

  /* If either regStart or regEnd are not non-negative integers, throw 
  ** an exception.  */
  if( pMWin->pStart ){
    assert( pMWin->eStart==TK_PRECEDING );
    sqlite3ExprCode(pParse, pMWin->pStart, regStart);
    windowCheckFrameValue(pParse, regStart, 0);
  }
  if( pMWin->pEnd ){

    sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
    windowCheckFrameValue(pParse, regEnd, 1);
  }

  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
  }

  sqlite3VdbeAddOp2(v, OP_Rewind, pMWin->iEphCsr, lblFlushDone);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrStart, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrEnd, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);

  /* Invoke AggStep function for each window function using the row that
  ** csrEnd currently points to. Or, if csrEnd is already at EOF,
  ** do nothing.  */
  addrTop = sqlite3VdbeCurrentAddr(v);




  if( pMWin->eEnd==TK_PRECEDING ){
    addrIfPos1 = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0 , 1);
  }
  sqlite3VdbeAddOp2(v, OP_Next, csrEnd, sqlite3VdbeCurrentAddr(v)+2);
  addr = sqlite3VdbeAddOp0(v, OP_Goto);


  windowAggStep(pParse, pMWin, csrEnd, 0, reg);
  if( pMWin->eEnd==TK_UNBOUNDED ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
    sqlite3VdbeJumpHere(v, addr);
    addrTop = sqlite3VdbeCurrentAddr(v);
  }else{
    sqlite3VdbeJumpHere(v, addr);
    if( pMWin->eEnd==TK_PRECEDING ){
      sqlite3VdbeJumpHere(v, addrIfPos1);
    }
  }

  if( pMWin->eEnd==TK_FOLLOWING ){
    addrIfPos1 = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0 , 1);
  }
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp3(v, 
        OP_AggFinal, pWin->regAccum, pWin->nArg, pWin->regResult
    );
    sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
  }
  sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
  sqlite3VdbeAddOp2(v, OP_Next, pMWin->iEphCsr, sqlite3VdbeCurrentAddr(v)+2);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, lblFlushDone);

  if( pMWin->eStart==TK_CURRENT || pMWin->eStart==TK_PRECEDING ){
    if( pMWin->eStart==TK_PRECEDING ){
      addrIfPos2 = sqlite3VdbeAddOp3(v, OP_IfPos, regStart, 0 , 1);
    }
    sqlite3VdbeAddOp2(v, OP_Next, csrStart, sqlite3VdbeCurrentAddr(v)+1);





    windowAggStep(pParse, pMWin, csrStart, 1, reg);



    if( pMWin->eStart==TK_PRECEDING ){
      sqlite3VdbeJumpHere(v, addrIfPos2);
    }
  }
  if( pMWin->eEnd==TK_FOLLOWING ){
    sqlite3VdbeJumpHere(v, addrIfPos1);
  }
  sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);

  /* flush_partition_done: */
  sqlite3VdbeResolveLabel(v, lblFlushDone);
  sqlite3VdbeAddOp1(v, OP_ResetSorter, pMWin->iEphCsr);
  sqlite3VdbeAddOp1(v, OP_Return, regFlushPart);

  /* Jump to here to skip over flush_partition */
  sqlite3VdbeJumpHere(v, addrGoto);
}

**
**========================================================================
**
** ROWS BETWEEN <expr> PRECEDING    AND <expr> PRECEDING
**
**   Replace the bit after "Rewind" in the above with:
**
**     if( (regEnd--)<=0 ){
**       AggStep (csr3)
**       Next (csr3)
**     }
**     AggFinal (xValue)
**     Gosub addrGosub
**     Next(csr)                  // if EOF goto flush_partition_done
**     if( (regStart--)<=0 ){
**       AggStep (csr2, xInverse)
**       Next (csr2)
**     }
**
** ROWS BETWEEN <expr> FOLLOWING    AND <expr> FOLLOWING
**
**   regEnd = regEnd - regStart
**   Rewind (csr,csr2,csr3)       // if EOF goto flush_partition_done
**     Aggstep (csr3)
**     Next(csr3)                 // if EOF fall-through
**     if( (regEnd--)<=0 ){
**       AggStep (csr2, xInverse)
**       Next (csr2)
**       if( (regStart--)<=0 ){
**         AggFinal (xValue)
**         Gosub addrGosub
**         Next(csr)              // if EOF goto flush_partition_done
**       }
**     }
**
** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> PRECEDING
** ROWS BETWEEN <expr> FOLLOWING    AND UNBOUNDED FOLLOWING
**
**   Similar to the above, except with regStart or regEnd set to infinity,
**   as appropriate.
**
**
**
*/
void sqlite3WindowCodeStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub,
  int *pbLoop
){
  Window *pMWin = p->pWin;

  if( pMWin->pStart || pMWin->pEnd ){
    assert( pMWin->eType==TK_ROWS );



    *pbLoop = 0;
    windowCodeRowExprStep(pParse, p, pWInfo, regGosub, addrGosub);
    return;
  }

  *pbLoop = 1;
  windowCodeDefaultStep(pParse, p, pWInfo, regGosub, addrGosub);
}

execsql_test 2.13 {
  SELECT a, sum(d) OVER (
    ORDER BY d 
    ROWS BETWEEN 2 PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
}

execsql_test 2.14 {
  SELECT a, sum(d) OVER (
    ORDER BY d 
    ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING
  ) FROM t1
}

execsql_test 2.15 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 0 PRECEDING
  ) FROM t1
}

execsql_test 2.16 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING
  ) FROM t1
}

execsql_test 2.17 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 2 PRECEDING
  ) FROM t1
}

execsql_test 2.18 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN UNBOUNDED PRECEDING AND 2 PRECEDING
  ) FROM t1
}


==========

puts $::fd finish_test
==========

do_execsql_test 2.13 {
  SELECT a, sum(d) OVER (
    ORDER BY d 
    ROWS BETWEEN 2 PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
} {1 21   2 21   3 21   4 20   5 18   6 15}

do_execsql_test 2.14 {
  SELECT a, sum(d) OVER (
    ORDER BY d 
    ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING
  ) FROM t1
} {1 {}   2 1   3 3   4 6   5 9   6 12}

do_execsql_test 2.15 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 0 PRECEDING
  ) FROM t1
} {2 2   4 6   6 10   1 1   3 4   5 8}

do_execsql_test 2.16 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING
  ) FROM t1
} {2 {}   4 2   6 4   1 {}   3 1   5 3}

do_execsql_test 2.17 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN 1 PRECEDING AND 2 PRECEDING
  ) FROM t1
} {2 {}   4 {}   6 {}   1 {}   3 {}   5 {}}

do_execsql_test 2.18 {
  SELECT a, sum(d) OVER (
    PARTITION BY b
    ORDER BY d 
    ROWS BETWEEN UNBOUNDED PRECEDING AND 2 PRECEDING
  ) FROM t1
} {2 {}   4 {}   6 2   1 {}   3 {}   5 1}

#==========================================================================

finish_test
#==========================================================================

do_execsql_test 3.1 {
  SELECT a, sum(d) OVER (