SQLite

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.14 2000/06/06 21:56:08 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetNString(&pParse->zErrMsg,"syntax error near \"",0,TOKEN.z,TOKEN.n,
                   "\"", 1, 0);

cmd ::= select(X).  {
  sqliteSelect(pParse, X, SRT_Callback, 0);
  sqliteSelectDelete(X);
}

%type select {Select*}
%destructor select {sqliteSelectDelete($$);}
%type oneselect {Select*}
%destructor oneselect {sqliteSelectDelete($$);}

select(A) ::= oneselect(X).                      {A = X;}
select(A) ::= select(X) joinop(Y) oneselect(Z).  {
    Z->op = Y;
    Z->pPrior = X;
    A = Z;
}
%type joinop {int}
joinop(A) ::= UNION.      {A = TK_UNION;}
joinop(A) ::= UNION ALL.  {A = TK_ALL;}
joinop(A) ::= INTERSECT.  {A = TK_INTERSECT;}
joinop(A) ::= EXCEPT.     {A = TK_EXCEPT;}
oneselect(A) ::= SELECT distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z). {
  A = sqliteSelectNew(W,X,Y,P,Q,Z,D);
}

// The "distinct" nonterminal is true (1) if the DISTINCT keyword is
// present and false (0) if it is not.
//
%type distinct {int}

groupby_opt(A) ::= .     {A = 0;}
groupby_opt(A) ::= GROUP BY exprlist(X).  {A = X;}

%type having_opt {Expr*}
%destructor having_opt {sqliteExprDelete($$);}
having_opt(A) ::= .      {A = 0;}
having_opt(A) ::= HAVING expr(X).  {A = X;}


cmd ::= DELETE FROM ID(X) where_opt(Y).
    {sqliteDeleteFrom(pParse, &X, Y);}

%type where_opt {Expr*}
%destructor where_opt {sqliteExprDelete($$);}

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.13 2000/06/06 21:56:08 drh Exp $
*/
#include "sqliteInt.h"

/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

  pNew->pEList = pEList;
  pNew->pSrc = pSrc;
  pNew->pWhere = pWhere;
  pNew->pGroupBy = pGroupBy;
  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->isDistinct = isDistinct;
  pNew->op = TK_SELECT;
  return pNew;
}

/*
** Delete the given Select structure and all of its substructures.
*/
void sqliteSelectDelete(Select *p){
  if( p==0 ) return;
  sqliteExprListDelete(p->pEList);
  sqliteIdListDelete(p->pSrc);
  sqliteExprDelete(p->pWhere);
  sqliteExprListDelete(p->pGroupBy);
  sqliteExprDelete(p->pHaving);
  sqliteExprListDelete(p->pOrderBy);
  sqliteSelectDelete(p->pPrior);
  sqliteFree(p);
}

/*
** Delete the aggregate information from the parse structure.
*/
void sqliteParseInfoReset(Parse *pParse){
  sqliteFree(pParse->aAgg);
  pParse->aAgg = 0;
  pParse->nAgg = 0;
  pParse->iAggCount = -1;
  pParse->useAgg = 0;
}

/*
** This routine generates the code for the inside of the inner loop
** of a SELECT.
**
** The pEList is used to determine the values for each column in the
** result row.  Except  if pEList==NULL, then we just read nField
** elements from the srcTab table.
*/
static int selectInnerLoop(
  Parse *pParse,          /* The parser context */
  ExprList *pEList,       /* List of values being extracted */
  int srcTab,             /* Pull data from this table */
  int nField,             /* Number of fields in the source table */
  ExprList *pOrderBy,     /* If not NULL, sort results using this key */
  int distinct,           /* If >=0, make sure results are distinct */
  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 */
){
  Vdbe *v = pParse->pVdbe;
  int i;

  /* Pull the requested fields.
  */
  if( pEList ){
    for(i=0; i<pEList->nExpr; i++){
      sqliteExprCode(pParse, pEList->a[i].pExpr);
    }
    nField = pEList->nExpr;
  }else{
    for(i=0; i<nField; i++){
      sqliteVdbeAddOp(v, OP_Field, srcTab, i, 0, 0);
    }
  }

  /* If the current result is not distinct, skip the rest
  ** of the processing for the current row.
  */
  if( distinct>=0 ){
    int lbl = sqliteVdbeMakeLabel(v);
    sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1, 0, 0);
    sqliteVdbeAddOp(v, OP_Distinct, distinct, lbl, 0, 0);
    sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, iContinue, 0, 0);
    sqliteVdbeAddOp(v, OP_String, 0, 0, "", lbl);
    sqliteVdbeAddOp(v, OP_Put, distinct, 0, 0, 0);
  }

  /* If there is an ORDER BY clause, then store the results
  ** in a sorter.
  */
  if( pOrderBy ){
    char *zSortOrder;
    sqliteVdbeAddOp(v, OP_SortMakeRec, pEList->nExpr, 0, 0, 0);
    zSortOrder = sqliteMalloc( pOrderBy->nExpr + 1 );
    if( zSortOrder==0 ) return 1;
    for(i=0; i<pOrderBy->nExpr; i++){
      zSortOrder[i] = pOrderBy->a[i].idx ? '-' : '+';
      sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
    }
    zSortOrder[pOrderBy->nExpr] = 0;
    sqliteVdbeAddOp(v, OP_SortMakeKey, pOrderBy->nExpr, 0, zSortOrder, 0);
    sqliteVdbeAddOp(v, OP_SortPut, 0, 0, 0, 0);
  }else 

  /* In this mode, write each query result to the key of the temporary
  ** table iParm.
  */
  if( eDest==SRT_Union ){
    sqliteVdbeAddOp(v, OP_MakeRecord, nField, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_String, iParm, 0, "", 0);
    sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
  }else 

  /* 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.
  */
  if( eDest==SRT_Except ){
    assert( pEList->nExpr==1 );
    sqliteVdbeAddOp(v, OP_String, 0, 0, "", 0);
    sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
  }else 

  /* 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.
  */
  if( eDest==SRT_Set ){
    assert( pEList->nExpr==1 );
    sqliteVdbeAddOp(v, OP_String, 0, 0, "", 0);
    sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
  }else 


  /* 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.
  */
  if( eDest==SRT_Mem ){
    sqliteVdbeAddOp(v, OP_MemStore, iParm, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, iBreak, 0, 0);
  }else

  /* If none of the above, send the data to the callback function.
  */
  {
    sqliteVdbeAddOp(v, OP_Callback, nField, 0, 0, 0);
  }
  return 0;
}

/*
** Generate code that will tell the VDBE how many columns there
** are in the result and the name for each column.  This information
** is used to provide "argc" and "azCol[]" values in the callback.
*/
static void generateColumnNames(Vdbe *v, IdList *pTabList, ExprList *pEList){
  int i;
  sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    if( pEList->a[i].zName ){
      char *zName = pEList->a[i].zName;
      int addr = sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
      if( zName[0]=='\'' || zName[0]=='"' ){
        sqliteVdbeDequoteP3(v, addr);
      }
      continue;
    }
    p = pEList->a[i].pExpr;
    if( p->op!=TK_FIELD || pTabList==0 ){
      char zName[30];
      sprintf(zName, "field%d", i+1);
      sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
    }else{
      if( pTabList->nId>1 ){
        char *zName = 0;
        Table *pTab = pTabList->a[p->iTable].pTab;
        char *zTab;
 
        zTab = pTabList->a[p->iTable].zAlias;
        if( zTab==0 ) zTab = pTab->zName;
        sqliteSetString(&zName, zTab, ".", pTab->aCol[p->iField].zName, 0);
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
        sqliteFree(zName);
      }else{
        Table *pTab = pTabList->a[0].pTab;
        char *zName = pTab->aCol[p->iField].zName;
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
      }
    }
  }
}

/*
** This routine is called to process a query that is really the union
** or intersection of two or more separate queries.
*/
static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){
  int rc;
  Select *pPrior;
  Vdbe *v;
  int i;

  /* Make sure we have a valid query engine.  If not, create a new one.
  */
  v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqliteVdbeCreate(pParse->db->pBe);
  }
  if( v==0 ){
    sqliteSetString(&pParse->zErrMsg, "out of memory", 0);
    pParse->nErr++;
    return 1;
  }

  assert( p->pPrior!=0 );
  pPrior = p->pPrior;
  switch( p->op ){
    case TK_ALL: {
      rc = sqliteSelect(pParse, pPrior, eDest, iParm);
      if( rc ) return rc;
      p->pPrior = 0;
      rc = sqliteSelect(pParse, p, eDest, iParm);
      p->pPrior = pPrior;
      break;
    }
    case TK_EXCEPT:
    case TK_UNION: {
      int unionTab;
      int op;

      if( eDest==SRT_Union ){
        unionTab = iParm;
      }else{
        unionTab = pParse->nTab++;          
        sqliteVdbeAddOp(v, OP_Open, unionTab, 1, 0, 0);
        sqliteVdbeAddOp(v, OP_KeyAsData, unionTab, 1, 0, 0);
      }
      rc = sqliteSelect(pParse, pPrior, SRT_Union, unionTab);
      if( rc ) return rc;
      op = p->op==TK_EXCEPT ? SRT_Except : SRT_Union;
      p->pPrior = 0;
      rc = sqliteSelect(pParse, p, op, unionTab);
      p->pPrior = pPrior;
      if( rc ) return rc;
      if( eDest!=SRT_Union ){
        int iCont, iBreak;
        assert( p->pEList );
        generateColumnNames(v, 0, p->pEList);
        iBreak = sqliteVdbeMakeLabel(v);
        iCont = sqliteVdbeAddOp(v, OP_Next, unionTab, iBreak, 0, 0);
        rc = selectInnerLoop(pParse, 0, unionTab, p->pEList->nExpr,
                             0, -1, eDest, iParm, 
                             iCont, iBreak);
        if( rc ) return 1;
        sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
        sqliteVdbeAddOp(v, OP_Close, unionTab, 0, 0, iBreak);
      }
      break;
    }
    case TK_INTERSECT: {
      int tab1, tab2;
      Select *pPrior;
      int iCont, iBreak;

      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      sqliteVdbeAddOp(v, OP_Open, tab1, 1, 0, 0);
      sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1, 0, 0);
      rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1);
      if( rc ) return rc;
      sqliteVdbeAddOp(v, OP_Open, tab2, 1, 0, 0);
      sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1, 0, 0);
      p->pPrior = 0;
      rc = sqliteSelect(pParse, p, SRT_Union, tab2);
      p->pPrior = pPrior;
      if( rc ) return rc;
      assert( p->pEList );
      generateColumnNames(v, 0, p->pEList);
      iBreak = sqliteVdbeMakeLabel(v);
      iCont = sqliteVdbeAddOp(v, OP_Next, tab1, iBreak, 0, 0);
      sqliteVdbeAddOp(v, OP_Key, tab1, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont, 0, 0);
      rc = selectInnerLoop(pParse, 0, tab1, p->pEList->nExpr,
                             0, -1, eDest, iParm, 
                             iCont, iBreak);
      if( rc ) return 1;
      sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
      sqliteVdbeAddOp(v, OP_Close, tab2, 0, 0, iBreak);
      sqliteVdbeAddOp(v, OP_Close, tab1, 0, 0, 0);
      break;
    }
  }
  assert( p->pEList && pPrior->pEList );
  if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
    sqliteSetString(&pParse->zErrMsg, "SELECTs have different numbers "
       "of columns and therefore cannot be joined", 0);
    pParse->nErr++;
    return 1;
  }
  return 0;
}

/*
** Generate code for the given SELECT statement.
**
** The results are distributed in various ways depending on the
** value of eDest and iParm.
**
**     eDest Value       Result
**     ------------    -------------------------------------------
**     SRT_Callback    Invoke the callback for each row of the result.
**
**     SRT_Mem         Store first result in memory cell iParm
**
**     SRT_Set         Store results as keys of a table with cursor iParm
**
**     SRT_Union       Store results as a key in a temporary table iParm
**
**     SRT_Except      Remove results form the temporary talbe iParm.
**
** This routine returns the number of errors.  If any errors are
** encountered, then an appropriate error message is left in
** pParse->zErrMsg.
**
** This routine does NOT free the Select structure passed in.  The
** calling function needs to do that.
*/
int sqliteSelect(
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  int eDest,             /* One of: SRT_Callback Mem Set Union Except */
  int iParm              /* Save result in this memory location, if >=0 */
){
  int i, j;
  WhereInfo *pWInfo;
  Vdbe *v;
  int isAgg = 0;         /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of fields to extract.  NULL means "*" */
  IdList *pTabList;      /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */

  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
    return multiSelect(pParse, p, eDest, iParm);
  }

  /* Make local copies of the parameters for this query.
  */
  pEList = p->pEList;
  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pOrderBy = p->pOrderBy;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  isDistinct = p->isDistinct;

  if( pEList==0 ){
    for(i=0; i<pTabList->nId; i++){
      Table *pTab = pTabList->a[i].pTab;
      for(j=0; j<pTab->nCol; j++){
        Expr *pExpr = sqliteExpr(TK_FIELD, 0, 0, 0);
        pExpr->iTable = i + pParse->nTab;
        pExpr->iField = j;
        p->pEList = pEList = sqliteExprListAppend(pEList, pExpr, 0);
      }
    }
  }

  /* If writing to memory or generating a set
  ** only a single column may be output.
  */

    sqliteVdbeAddOp(v, OP_SortOpen, 0, 0, 0, 0);
  }

  /* Identify column names if we will be using in the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  */
  if( eDest==SRT_Callback ){





















    generateColumnNames(v, pTabList, pEList);












  }

  /* Reset the aggregator
  */
  if( isAgg ){
    sqliteVdbeAddOp(v, OP_AggReset, 0, pParse->nAgg, 0, 0);
  }

  pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
  if( pWInfo==0 ) return 1;

  /* Use the standard inner loop if we are not dealing with
  ** aggregates
  */
  if( !isAgg ){
    if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
                    pWInfo->iContinue, pWInfo->iBreak) ){
       return 1;
    }
  }

  /* If we are dealing with aggregates, then to the special aggregate
  ** processing.  

    int endagg = sqliteVdbeMakeLabel(v);
    int startagg;
    startagg = sqliteVdbeAddOp(v, OP_AggNext, 0, endagg, 0, 0);
    pParse->useAgg = 1;
    if( pHaving ){
      sqliteExprIfFalse(pParse, pHaving, startagg);
    }
    if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
                    startagg, endagg) ){
      return 1;
    }
    sqliteVdbeAddOp(v, OP_Goto, 0, startagg, 0, 0);
    sqliteVdbeAddOp(v, OP_Noop, 0, 0, 0, endagg);
    pParse->useAgg = 0;
  }

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.19 2000/06/06 21:56:08 drh Exp $
*/
#include "sqlite.h"
#include "dbbe.h"
#include "vdbe.h"
#include "parse.h"
#include <gdbm.h>
#include <stdio.h>

  int isDistinct;        /* True if the DISTINCT keyword is present */
  ExprList *pEList;      /* The fields of the result */
  IdList *pSrc;          /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  Select *pPrior;        /* Prior select to which this one joins */
};

/*
** The results of a select can be distributed in several ways.
*/
#define SRT_Callback     1  /* Invoke a callback with each row of result */
#define SRT_Mem          2  /* Store result in a memory cell */
#define SRT_Set          3  /* Store result as unique keys in a table */
#define SRT_Union        5  /* Store result as keys in a table */
#define SRT_Except       6  /* Remove result from a UNION table */

/*
** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
** we have to do some additional analysis of expressions.  An instance
** of the following structure holds information about a single subexpression
** somewhere in the SELECT statement.  An array of these structures holds
** all the information we need to generate code for aggregate

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.8 2000/06/06 21:56:08 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include <stdlib.h>

/*
** All the keywords of the SQL language are stored as in a hash

  { "CREATE",            0, TK_CREATE,           0 },
  { "DEFAULT",           0, TK_DEFAULT,          0 },
  { "DELETE",            0, TK_DELETE,           0 },
  { "DELIMITERS",        0, TK_DELIMITERS,       0 },
  { "DESC",              0, TK_DESC,             0 },
  { "DISTINCT",          0, TK_DISTINCT,         0 },
  { "DROP",              0, TK_DROP,             0 },
  { "EXCEPT",            0, TK_EXCEPT,           0 },
  { "EXPLAIN",           0, TK_EXPLAIN,          0 },
  { "FROM",              0, TK_FROM,             0 },
  { "GLOB",              0, TK_GLOB,             0 },
  { "GROUP",             0, TK_GROUP,            0 },
  { "HAVING",            0, TK_HAVING,           0 },
  { "IN",                0, TK_IN,               0 },
  { "INDEX",             0, TK_INDEX,            0 },
  { "INSERT",            0, TK_INSERT,           0 },
  { "INTERSECT",         0, TK_INTERSECT,        0 },
  { "INTO",              0, TK_INTO,             0 },
  { "IS",                0, TK_IS,               0 },
  { "ISNULL",            0, TK_ISNULL,           0 },
  { "KEY",               0, TK_KEY,              0 },
  { "LIKE",              0, TK_LIKE,             0 },
  { "NOT",               0, TK_NOT,              0 },
  { "NOTNULL",           0, TK_NOTNULL,          0 },
  { "NULL",              0, TK_NULL,             0 },
  { "ON",                0, TK_ON,               0 },
  { "OR",                0, TK_OR,               0 },
  { "ORDER",             0, TK_ORDER,            0 },
  { "PRIMARY",           0, TK_PRIMARY,          0 },
  { "SELECT",            0, TK_SELECT,           0 },
  { "SET",               0, TK_SET,              0 },
  { "TABLE",             0, TK_TABLE,            0 },
  { "UNION",             0, TK_UNION,            0 },
  { "UNIQUE",            0, TK_UNIQUE,           0 },
  { "UPDATE",            0, TK_UPDATE,           0 },
  { "USING",             0, TK_USING,            0 },
  { "VACUUM",            0, TK_VACUUM,           0 },
  { "VALUES",            0, TK_VALUES,           0 },
  { "WHERE",             0, TK_WHERE,            0 },
};

** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.23 2000/06/06 21:56:08 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance
** of the following structure.
*/
typedef struct VdbeOp Op;

/*
** Every table that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct VdbeTable {
  DbbeTable *pTable;    /* The table structure of the backend */
  int index;            /* The next index to extract */
  int keyAsData;        /* The OP_Field command works on key instead of data */
};
typedef struct VdbeTable VdbeTable;

/*
** A sorter builds a list of elements to be sorted.  Each element of
** the list is an instance of the following structure.
*/

** change, be sure to change this array to match.  You can use the
** "opNames.awk" awk script which is part of the source tree to regenerate
** this array, then copy and paste it into this file, if you want.
*/
static char *zOpName[] = { 0,
  "Open",           "Close",          "Fetch",          "New",
  "Put",            "Distinct",       "Found",          "NotFound",
  "Delete",         "Field",          "KeyAsData",      "Key",
  "Rewind",         "Next",           "Destroy",        "Reorganize",
  "ResetIdx",       "NextIdx",        "PutIdx",         "DeleteIdx",
  "MemLoad",        "MemStore",       "ListOpen",       "ListWrite",
  "ListRewind",     "ListRead",       "ListClose",      "SortOpen",
  "SortPut",        "SortMakeRec",    "SortMakeKey",    "Sort",
  "SortNext",       "SortKey",        "SortCallback",   "SortClose",
  "FileOpen",       "FileRead",       "FileField",      "FileClose",
  "AggReset",       "AggFocus",       "AggIncr",        "AggNext",
  "AggSet",         "AggGet",         "SetInsert",      "SetFound",
  "SetNotFound",    "SetClear",       "MakeRecord",     "MakeKey",
  "Goto",           "If",             "Halt",           "ColumnCount",
  "ColumnName",     "Callback",       "Integer",        "String",
  "Null",           "Pop",            "Dup",            "Pull",
  "Add",            "AddImm",         "Subtract",       "Multiply",
  "Divide",         "Min",            "Max",            "Like",
  "Glob",           "Eq",             "Ne",             "Lt",
  "Le",             "Gt",             "Ge",             "IsNull",
  "NotNull",        "Negative",       "And",            "Or",
  "Not",            "Concat",         "Noop",         
};

/*
** Given the name of an opcode, return its number.  Return 0 if
** there is no match.
**
** This routine is used for testing and debugging.

            zKey = p->zStack[tos];
          }
          sqliteDbbeDelete(p->aTab[i].pTable, nKey, zKey);
        }
        PopStack(p, 1);
        break;
      }

      /* Opcode: KeyAsData P1 P2 *
      **
      ** Turn the key-as-data mode for cursor P1 either on (if P2==1) or
      ** off (if P2==0).  In key-as-data mode, the OP_Fetch opcode pulls
      ** data off of the key rather than the data.  This is useful for
      ** outer joins and stuff...
      */
      case OP_KeyAsData: {
        int i = pOp->p1;
        VdbeTable *pTab;
        if( i>=0 && i<p->nTable && p->aTab[i].pTable!=0 ){
          p->aTab[i].keyAsData = pOp->p2;
        }
        break;
      }

      /* Opcode: Field P1 P2 *
      **
      ** Push onto the stack the value of the P2-th field from the
      ** most recent Fetch from table P1.
      ** 
      ** The value pushed is just a pointer to the data in the cursor.

        int p2 = pOp->p2;
        int tos = ++p->tos;
        DbbeTable *pTab;
        char *z;

        if( NeedStack(p, tos) ) goto no_mem;
        if( i>=0 && i<p->nTable && (pTab = p->aTab[i].pTable)!=0 ){
          if( p->aTab[i].keyAsData ){
            amt = sqliteDbbeKeyLength(pTab);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)sqliteDbbeReadKey(pTab, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = sqliteDbbeReadKey(pTab, *pAddr);
          }else{
            amt = sqliteDbbeDataLength(pTab);
            if( amt<=sizeof(int)*(p2+1) ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            pAddr = (int*)sqliteDbbeReadData(pTab, sizeof(int)*p2);
            if( *pAddr==0 ){
              p->aStack[tos].flags = STK_Null;
              break;
            }
            z = sqliteDbbeReadData(pTab, *pAddr);
          }
          p->zStack[tos] = z;
          p->aStack[tos].n = strlen(z) + 1;
          p->aStack[tos].flags = STK_Str;
        }
        break;
      }

      /* Opcode: Key P1 * *

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.9 2000/06/06 21:56:08 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

#define OP_New                 4
#define OP_Put                 5
#define OP_Distinct            6
#define OP_Found               7
#define OP_NotFound            8
#define OP_Delete              9
#define OP_Field              10
#define OP_KeyAsData          11
#define OP_Key                12
#define OP_Rewind             13
#define OP_Next               14

#define OP_Destroy            15
#define OP_Reorganize         16

#define OP_ResetIdx           17
#define OP_NextIdx            18
#define OP_PutIdx             19
#define OP_DeleteIdx          20

#define OP_MemLoad            21
#define OP_MemStore           22

#define OP_ListOpen           23
#define OP_ListWrite          24
#define OP_ListRewind         25
#define OP_ListRead           26
#define OP_ListClose          27

#define OP_SortOpen           28
#define OP_SortPut            29
#define OP_SortMakeRec        30
#define OP_SortMakeKey        31
#define OP_Sort               32
#define OP_SortNext           33
#define OP_SortKey            34
#define OP_SortCallback       35
#define OP_SortClose          36

#define OP_FileOpen           37
#define OP_FileRead           38
#define OP_FileField          39
#define OP_FileClose          40

#define OP_AggReset           41
#define OP_AggFocus           42
#define OP_AggIncr            43
#define OP_AggNext            44
#define OP_AggSet             45
#define OP_AggGet             46

#define OP_SetInsert          47
#define OP_SetFound           48
#define OP_SetNotFound        49
#define OP_SetClear           50

#define OP_MakeRecord         51
#define OP_MakeKey            52

#define OP_Goto               53
#define OP_If                 54
#define OP_Halt               55

#define OP_ColumnCount        56
#define OP_ColumnName         57
#define OP_Callback           58

#define OP_Integer            59
#define OP_String             60
#define OP_Null               61
#define OP_Pop                62
#define OP_Dup                63
#define OP_Pull               64

#define OP_Add                65
#define OP_AddImm             66
#define OP_Subtract           67
#define OP_Multiply           68
#define OP_Divide             69
#define OP_Min                70
#define OP_Max                71
#define OP_Like               72
#define OP_Glob               73
#define OP_Eq                 74
#define OP_Ne                 75
#define OP_Lt                 76
#define OP_Le                 77
#define OP_Gt                 78
#define OP_Ge                 79
#define OP_IsNull             80
#define OP_NotNull            81
#define OP_Negative           82
#define OP_And                83
#define OP_Or                 84
#define OP_Not                85
#define OP_Concat             86
#define OP_Noop               87

#define OP_MAX                87

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/
Vdbe *sqliteVdbeCreate(Dbbe*);
int sqliteVdbeAddOp(Vdbe*,int,int,int,const char*,int);