SQLite

/*
** 2005 July 8
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    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 associated with the ANALYZE command.
**
** @(#) $Id: analyze.c,v 1.26 2008/01/02 14:28:13 drh Exp $
*/
#ifndef SQLITE_OMIT_ANALYZE
#include "sqliteInt.h"

/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.

    ** Cells iMem through iMem+nCol are initialized to 0.  The others
    ** are initialized to NULL.
    */
    for(i=0; i<=nCol; i++){
      sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem+i);
    }
    for(i=0; i<nCol; i++){
      sqlite3VdbeAddOp(v, OP_MemNull, 0, iMem+nCol+i+1);
    }

    /* Do the analysis.
    */
    endOfLoop = sqlite3VdbeMakeLabel(v);
    sqlite3VdbeAddOp(v, OP_Rewind, iIdxCur, endOfLoop);
    topOfLoop = sqlite3VdbeCurrentAddr(v);

**    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 1.323 2008/01/02 14:28:13 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

    case TK_SELECT: {
      /* This has to be a scalar SELECT.  Generate code to put the
      ** value of this select in a memory cell and record the number
      ** of the memory cell in iColumn.
      */
      static const Token one = { (u8*)"1", 0, 1 };
      Select *pSel;

      int sop;
      int iMem;


      pSel = pExpr->pSelect;
      iMem = pParse->nMem++;
      if( pExpr->op==TK_SELECT ){
        sop = SRT_Mem;
        sqlite3VdbeAddOp(v, OP_MemNull, 0, iMem);
        VdbeComment((v, "Init subquery result"));
      }else{
        sop = SRT_Exists;
        sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem);
        VdbeComment((v, "Init EXISTS result"));
      }
      sqlite3ExprDelete(pSel->pLimit);
      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
      if( sqlite3Select(pParse, pSel, sop, iMem, 0, 0, 0, 0) ){
        return;
      }
      pExpr->iColumn = iMem;
      break;
    }
  }

  if( testAddr ){
    sqlite3VdbeJumpHere(v, testAddr);
  }

**    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 1.375 2008/01/02 14:28:13 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

** stack are distinct.  iTab is a sorting index that holds previously
** seen combinations of the N values.  A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the N+1 values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct_OLD(
  Vdbe *v,           /* Generate code into this VM */
  int iTab,          /* A sorting index used to test for distinctness */
  int addrRepeat,    /* Jump to here if not distinct */
  int N              /* The top N elements of the stack must be distinct */
){
  sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
  sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
  sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
  VdbeComment((v, "skip indistinct records"));
  sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
}

/*
** Add code that will check to make sure the top N elements of the
** stack are distinct.  iTab is a sorting index that holds previously
** seen combinations of the N values.  A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the N+1 values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct(
  Vdbe *v,           /* Generate code into this VM */
  int iTab,          /* A sorting index used to test for distinctness */
  int addrRepeat,    /* Jump to here if not distinct */
  int iMem           /* First element */
){
  sqlite3VdbeAddOp(v, OP_RegMakeRec, iMem, 0);
  sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
  sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
  VdbeComment((v, "skip indistinct records"));
  sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
}

/*
** Generate an error message when a SELECT is used within a subexpression

  int eDest,              /* How to dispose of the results */
  int iParm,              /* An argument to the disposal method */
  int iContinue,          /* Jump here to continue with next row */
  int iBreak,             /* Jump here to break out of the inner loop */
  char *aff               /* affinity string if eDest is SRT_Union */
){
  Vdbe *v = pParse->pVdbe;
  int i, n;
  int hasDistinct;        /* True if the DISTINCT keyword is present */
  int iMem;               /* Start of memory holding result set */

  if( v==0 ) return 0;
  assert( pEList!=0 );

  /* If there was a LIMIT clause on the SELECT statement, then do the check
  ** to see if this row should be output.
  */
  hasDistinct = distinct>=0 && pEList->nExpr>0;
  if( pOrderBy==0 && !hasDistinct ){
    codeOffset(v, p, iContinue, 0);
  }

  /* Pull the requested columns.
  */
  if( nColumn>0 ){
    n = nColumn;
  }else{
    n = pEList->nExpr;
  }
  iMem = pParse->nMem;
  pParse->nMem += n+1;
  sqlite3VdbeAddOp(v, OP_MemInt, n, iMem);
  if( nColumn>0 ){
    for(i=0; i<nColumn; i++){
      sqlite3VdbeOp3Int(v, OP_Column, srcTab, i, iMem+i+1);
    }
  }else{

    for(i=0; i<n; i++){
      sqlite3ExprIntoReg(pParse, pEList->a[i].pExpr, iMem+i+1);
    }
  }
  nColumn = n;

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( hasDistinct ){
    assert( pEList!=0 );
    assert( pEList->nExpr==nColumn );
    codeDistinct(v, distinct, iContinue, iMem);
    if( pOrderBy==0 ){
      codeOffset(v, p, iContinue, nColumn);
    }
  }

  if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
    return 0;
  }

  switch( eDest ){
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      sqlite3VdbeAddOp(v, OP_RegMakeRec, iMem, 0);
      if( aff ){
        sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
      }
      sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
    ** the temporary table iParm.
    */
    case SRT_Except: {
      int addr;
      addr = sqlite3VdbeAddOp(v, OP_RegMakeRec, iMem, 0);
      sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
      sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
      sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
      break;
    }
#endif

    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_EphemTab: {
      sqlite3VdbeAddOp(v, OP_RegMakeRec, iMem, 0);
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
        sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
        sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
      }
      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;

      assert( nColumn==1 );


      addr2 = sqlite3VdbeAddOp(v, OP_IfMemNull, iMem+1, 0);
      p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr,(iParm>>16)&0xff);
      if( pOrderBy ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        sqlite3VdbeAddOp(v, OP_MemLoad, iMem+1, 0);
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        sqlite3VdbeOp3(v, OP_RegMakeRec, iMem, 0, &p->affinity, 1);
        sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
      }
      sqlite3VdbeJumpHere(v, addr2);
      break;
    }

    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp(v, OP_MemInt, 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 );
      sqlite3VdbeAddOp(v, OP_MemLoad, iMem+1, 0);
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        sqlite3VdbeAddOp(v, OP_MemStore, 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_Subroutine:
    case SRT_Callback: {
      if( pOrderBy ){
        sqlite3VdbeAddOp(v, OP_RegMakeRec, iMem, 0);
        pushOntoSorter(pParse, pOrderBy, p);
      }else if( eDest==SRT_Subroutine ){
        for(i=0; i<nColumn; i++) sqlite3VdbeAddOp(v, OP_MemLoad, iMem+i+1, 0);
        sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
      }else{
        sqlite3VdbeAddOp(v, OP_ResultRow, iMem+1, 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: {
      assert( eDest==SRT_Discard );

      break;
    }
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.
  */

  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pFunc;
  if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
    return;
  }
  for(i=0; i<pAggInfo->nColumn; i++){
    sqlite3VdbeAddOp(v, OP_MemNull, 0, pAggInfo->aCol[i].iMem);
  }
  for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
    sqlite3VdbeAddOp(v, OP_MemNull, 0, pFunc->iMem);
    if( pFunc->iDistinct>=0 ){
      Expr *pE = pFunc->pExpr;
      if( pE->pList==0 || pE->pList->nExpr!=1 ){
        sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
           "by an expression");
        pFunc->iDistinct = -1;
      }else{

      sqlite3ExprCodeExprList(pParse, pList);
    }else{
      nArg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct_OLD(v, pF->iDistinct, addrNext, 1);
    }
    if( pF->pFunc->needCollSeq ){
      CollSeq *pColl = 0;
      struct ExprList_item *pItem;
      int j;
      assert( pList!=0 );  /* pList!=0 if pF->pFunc->needCollSeq is true */
      for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){

**
** 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 1.663 2008/01/02 14:28:13 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

  int nHdr = 0;          /* Number of bytes of header space */
  u64 nByte = 0;         /* Data space required for this record */
  int nZero = 0;         /* Number of zero bytes at the end of the record */
  int nVarint;           /* Number of bytes in a varint */
  u32 serial_type;       /* Type field */
  int containsNull = 0;  /* True if any of the data fields are NULL */
  Mem *pData0;           /* Bottom of the stack */
  Mem *pLast;            /* Top of the stack */
  int leaveOnStack;      /* If true, leave the entries on the stack */
  int nField;            /* Number of fields in the record */
  int jumpIfNull;        /* Jump here if non-zero and any entries are NULL. */
  int addRowid;          /* True to append a rowid column at the end */
  char *zAffinity;       /* The affinity string for the record */
  int file_format;       /* File format to use for encoding */
  int i;                 /* Space used in zNewRecord[] */

  if( pOp->opcode==OP_RegMakeRec || pOp->opcode==OP_RegMakeIRec ){
    Mem *pCount;
    assert( nField>=0 && nField<p->nMem );
    pCount = &p->aMem[nField];
    assert( pCount->flags & MEM_Int );
    assert( pCount->u.i>=0 && pCount->u.i+nField<p->nMem );
    leaveOnStack = 1;
    nField = pCount->u.i;
    pData0 = &pCount[1];
    pLast = &pData0[nField-1];
  }else{
    pData0 = &pTos[1-nField];
    pLast = pTos;
    assert( pData0>=p->aStack );
  }
  containsNull = 0;
  file_format = p->minWriteFileFormat;

  /* Loop through the elements that will make up the record to figure
  ** out how much space is required for the new record.
  */
  for(pRec=pData0; pRec<=pLast; pRec++){
    int len;
    if( zAffinity ){
      applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
    }
    if( pRec->flags&MEM_Null ){
      containsNull = 1;
    }

    }
  }else{
    zNewRecord = (u8*)zTemp;
  }

  /* Write the record */
  i = sqlite3PutVarint(zNewRecord, nHdr);
  for(pRec=pData0; pRec<=pLast; pRec++){
    serial_type = sqlite3VdbeSerialType(pRec, file_format);
    i += sqlite3PutVarint(&zNewRecord[i], serial_type);      /* serial type */
  }
  if( addRowid ){
    i += sqlite3PutVarint(&zNewRecord[i], sqlite3VdbeSerialType(pRowid, 0));
  }
  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
    i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRec, file_format);
  }
  if( addRowid ){
    i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRowid, 0);
  }
  assert( i==nByte );

  assert( pMem->flags==MEM_Int );
  if( pMem->u.i==0 ){
     pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: IfMemNull P1 P2 *
**
** If the value of memory cell P1 is NULL, jump to P2. 
*/
case OP_IfMemNull: {        /* no-push */
  int i = pOp->p1;
  assert( i>=0 && i<p->nMem );
  if( p->aMem[i].flags & MEM_Null ){
     pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: MemNull * P2 *
**
** Store a NULL in memory cell P2
*/
case OP_MemNull: {
  assert( pOp->p2>=0 && pOp->p2<p->nMem );
  sqlite3VdbeMemSetNull(&p->aMem[pOp->p2]);
  break;
}

/* Opcode: MemInt P1 P2 *
**
** Store the integer value P1 in memory cell P2.
*/