SQLite

**     DROP TABLE
**     CREATE INDEX
**     DROP INDEX
**     creating expressions and ID lists
**     COPY
**     VACUUM
**
** $Id: build.c,v 1.19 2000/06/21 13:59:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is called after a single SQL statement has been
** parsed and we want to execute the VDBE code to implement 
** that statement.  Prior action routines should have already

}

/*
** Remove the given index from the index hash table, and free
** its memory structures.
**
** The index is removed from the database hash table, but it is
** not unlinked from the Table that is being indexed.  Unlinking
** from the Table must be done by the calling function.
*/
static void sqliteDeleteIndex(sqlite *db, Index *pIndex){
  int h;
  if( pIndex->zName ){
    h = sqliteHashNoCase(pIndex->zName, 0) % N_HASH;
    if( db->apIdxHash[h]==pIndex ){
      db->apIdxHash[h] = pIndex->pHash;
    }else{
      Index *p;
      for(p=db->apIdxHash[h]; p && p->pHash!=pIndex; p=p->pHash){}
      if( p && p->pHash==pIndex ){
        p->pHash = pIndex->pHash;
      }
    }
  }
  sqliteFree(pIndex);
}

/*
** Remove the memory data structures associated with the given
** Table.  No changes are made to disk by this routine.
**
** This routine just deletes the data structure.  It does not unlink
** the table data structure from the hash table.  But does it destroy
** memory structures of the indices associated with the table.
*/
void sqliteDeleteTable(sqlite *db, Table *pTable){
  int i;

  pIndex = sqliteMalloc( sizeof(Index) + strlen(zName) + 1 +
                        sizeof(int)*pList->nId );
  if( pIndex==0 ){
    sqliteSetString(&pParse->zErrMsg, "out of memory", 0);
    pParse->nErr++;
    goto exit_create_index;
  }
  pIndex->aiColumn = (int*)&pIndex[1];
  pIndex->zName = (char*)&pIndex->aiColumn[pList->nId];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nId;

  /* Scan the names of the columns of the table to be indexed and
  ** load the column indices into the Index structure.  Report an error
  ** if any column is not found.
  */
  for(i=0; i<pList->nId; i++){
    for(j=0; j<pTab->nCol; j++){
      if( sqliteStrICmp(pList->a[i].zName, pTab->aCol[j].zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName, 
        " has no column named ", pList->a[i].zName, 0);
      pParse->nErr++;
      sqliteFree(pIndex);
      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;
  }

  /* Link the new Index structure to its table and to the other
  ** in-memory database structures.
  */
  if( pParse->explain==0 ){
    h = sqliteHashNoCase(pIndex->zName, 0) % N_HASH;

      sqliteVdbeChangeP3(v, base+4, pTab->zName, 0);
      sqliteVdbeChangeP3(v, base+5, pStart->z, n);
    }
    lbl1 = sqliteVdbeMakeLabel(v);
    lbl2 = sqliteVdbeMakeLabel(v);
    sqliteVdbeAddOp(v, OP_Next, 0, lbl2, 0, lbl1);
    sqliteVdbeAddOp(v, OP_Key, 0, 0, 0, 0);
    for(i=0; i<pIndex->nColumn; i++){
      sqliteVdbeAddOp(v, OP_Field, 0, pIndex->aiColumn[i], 0, 0);
    }
    sqliteVdbeAddOp(v, OP_MakeKey, pIndex->nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_PutIdx, 1, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, lbl1, 0, 0);
    sqliteVdbeAddOp(v, OP_Noop, 0, 0, 0, lbl2);
    sqliteVdbeAddOp(v, OP_Close, 1, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Close, 0, 0, 0, 0);
  }

    }
    sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Put, 0, 0, 0, 0);
    for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( pIdx->pNext ){
        sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
      }
      for(j=0; j<pIdx->nColumn; j++){
        sqliteVdbeAddOp(v, OP_FileField, pIdx->aiColumn[j], 0, 0, 0);
      }
      sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_PutIdx, i, 0, 0, 0);
    }
    sqliteVdbeAddOp(v, OP_Goto, 0, addr, 0, 0);
    sqliteVdbeAddOp(v, OP_Noop, 0, 0, 0, end);
  }
  
copy_cleanup:

** sqlite and the code that does the actually reading and writing
** of information to the disk.
**
** This file uses GDBM as the database backend.  It should be
** relatively simple to convert to a different database such
** as NDBM, SDBM, or BerkeleyDB.
**
** $Id: dbbe.c,v 1.15 2000/06/21 13:59:11 drh Exp $
*/
#include "sqliteInt.h"
#include <gdbm.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <time.h>

/*
** Information about each open disk file is an instance of this 
** structure.  There will only be one such structure for each
** disk file.  If the VDBE opens the same file twice (as will happen
** for a self-join, for example) then two DbbeCursor structures are
** created but there is only a single BeFile structure with an
** nRef of 2.
*/
typedef struct BeFile BeFile;
struct BeFile {
  char *zName;            /* Name of the file */
  GDBM_FILE dbf;          /* The file itself */

  char **azTemp;     /* Names of the temporary files */
  struct rc4 rc4;    /* The random number generator */
};

/*
** An cursor into a database file is an instance of the following structure.
** There can only be a single BeFile structure for each disk file, but
** there can be multiple DbbeCursor structures.  Each DbbeCursor represents
** a cursor pointing to a particular part of the open BeFile.  The
** BeFile.nRef field hold a count of the number of DbbeCursor structures
** associated with the same disk file.
*/
struct DbbeCursor {
  Dbbe *pBe;         /* The database of which this record is a part */
  BeFile *pFile;     /* The database file for this table */
  datum key;         /* Most recently used key */
  datum data;        /* Most recent data */
  int needRewind;    /* Next key should be the first */
  int readPending;   /* The fetch hasn't actually been done yet */
};

  sqliteFree(pBe->azTemp);
  sqliteFree(pBe->apTemp);
  memset(pBe, 0, sizeof(*pBe));
  sqliteFree(pBe);
}

/*
** Translate the name of an SQL table (or index) into the name 
** of a file that holds the key/data pairs for that table or
** index.  Space to hold the filename is obtained from
** sqliteMalloc() and must be freed by the calling function.
*/
static char *sqliteFileOfTable(Dbbe *pBe, const char *zTable){
  char *zFile = 0;
  int i;
  sqliteSetString(&zFile, pBe->zDir, "/", zTable, ".tbl", 0);
  if( zFile==0 ) return 0;

    zBuf[j++] = zRandomChars[c];
  }
  zBuf[j] = 0;
}

/*
** Open a new table cursor.  Write a pointer to the corresponding
** DbbeCursor structure into *ppCursr.  Return an integer success
** code:
**
**    SQLITE_OK          It worked!
**
**    SQLITE_NOMEM       sqliteMalloc() failed
**
**    SQLITE_PERM        Attempt to access a file for which file
**                       access permission is denied
**
**    SQLITE_BUSY        Another thread or process is already using
**                       the corresponding file and has that file locked.
**
**    SQLITE_READONLY    The current thread already has this file open
**                       readonly but you are trying to open for writing.
**                       (This can happen if a SELECT callback tries to
**                       do an UPDATE or DELETE.)
**
** If zTable is 0 or "", then a temporary database file is created and
** a cursor to that temporary file is opened.  The temporary file
** will be deleted from the disk when it is closed.
*/
int sqliteDbbeOpenCursor(
  Dbbe *pBe,              /* The database the table belongs to */
  const char *zTable,     /* The SQL name of the file to be opened */
  int writeable,          /* True to open for writing */
  DbbeCursor **ppCursr    /* Write the resulting table pointer here */
){
  char *zFile;            /* Name of the table file */
  DbbeCursor *pCursr;     /* The new table cursor */
  BeFile *pFile;          /* The underlying data file for this table */
  int rc = SQLITE_OK;     /* Return value */
  int rw_mask;            /* Permissions mask for opening a table */
  int mode;               /* Mode for opening a table */

  *ppCursr = 0;
  pCursr = sqliteMalloc( sizeof(*pCursr) );
  if( pCursr==0 ) return SQLITE_NOMEM;
  if( zTable ){
    zFile = sqliteFileOfTable(pBe, zTable);
    for(pFile=pBe->pOpen; pFile; pFile=pFile->pNext){
      if( strcmp(pFile->zName,zFile)==0 ) break;
    }
  }else{
    pFile = 0;

  }else{
    sqliteFree(zFile);
    pFile->nRef++;
    if( writeable && !pFile->writeable ){
      rc = SQLITE_READONLY;
    }
  }
  pCursr->pBe = pBe;
  pCursr->pFile = pFile;
  pCursr->readPending = 0;
  pCursr->needRewind = 1;
  *ppCursr = pCursr;
  return rc;
}

/*
** Drop a table from the database.  The file on the disk that corresponds
** to this table is deleted.
*/
void sqliteDbbeDropTable(Dbbe *pBe, const char *zTable){
  char *zFile;            /* Name of the table file */

  zFile = sqliteFileOfTable(pBe, zTable);
  unlink(zFile);
  sqliteFree(zFile);
}

/*
** Reorganize a table to reduce search times and disk usage.
*/
void sqliteDbbeReorganizeTable(Dbbe *pBe, const char *zTable){
  DbbeCursor *pCrsr;

  if( sqliteDbbeOpenCursor(pBe, zTable, 1, &pCrsr)!=SQLITE_OK ){
    return;
  }
  if( pCrsr && pCrsr->pFile && pCrsr->pFile->dbf ){
    gdbm_reorganize(pCrsr->pFile->dbf);
  }
  if( pCrsr ){
    sqliteDbbeCloseCursor(pCrsr);
  }
}

/*
** Close a cursor previously opened by sqliteDbbeOpenCursor().
**
** There can be multiple cursors pointing to the same open file.
** The underlying file is not closed until all cursors have been
** closed.  This routine decrements the BeFile.nref field of the
** underlying file and closes the file when nref reaches 0.
*/
void sqliteDbbeCloseCursor(DbbeCursor *pCursr){
  BeFile *pFile;
  Dbbe *pBe;
  if( pCursr==0 ) return;
  pFile = pCursr->pFile;
  pBe = pCursr->pBe;
  pFile->nRef--;
  if( pFile->dbf!=NULL ){
    gdbm_sync(pFile->dbf);
  }
  if( pFile->nRef<=0 ){
    if( pFile->dbf!=NULL ){
      gdbm_close(pFile->dbf);

    if( pFile->delOnClose ){
      unlink(pFile->zName);
    }
    sqliteFree(pFile->zName);
    memset(pFile, 0, sizeof(*pFile));
    sqliteFree(pFile);
  }
  if( pCursr->key.dptr ) free(pCursr->key.dptr);
  if( pCursr->data.dptr ) free(pCursr->data.dptr);
  memset(pCursr, 0, sizeof(*pCursr));
  sqliteFree(pCursr);
}

/*
** Clear the given datum
*/
static void datumClear(datum *p){
  if( p->dptr ) free(p->dptr);
  p->dptr = 0;
  p->dsize = 0;
}

/*
** Fetch a single record from an open cursor.  Return 1 on success
** and 0 on failure.
*/
int sqliteDbbeFetch(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  key.dsize = nKey;
  key.dptr = pKey;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, key);
  }
  return pCursr->data.dptr!=0;
}

/*
** Return 1 if the given key is already in the table.  Return 0
** if it is not.
*/
int sqliteDbbeTest(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int result = 0;
  key.dsize = nKey;
  key.dptr = pKey;
  if( pCursr->pFile && pCursr->pFile->dbf ){
    result = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return result;
}

/*
** Copy bytes from the current key or data into a buffer supplied by
** the calling function.  Return the number of bytes copied.
*/
int sqliteDbbeCopyKey(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( offset>=pCursr->key.dsize ) return 0;
  if( offset+size>pCursr->key.dsize ){
    n = pCursr->key.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->key.dptr[offset], n);
  return n;
}
int sqliteDbbeCopyData(DbbeCursor *pCursr, int offset, int size, char *zBuf){
  int n;
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset>=pCursr->data.dsize ) return 0;
  if( offset+size>pCursr->data.dsize ){
    n = pCursr->data.dsize - offset;
  }else{
    n = size;
  }
  memcpy(zBuf, &pCursr->data.dptr[offset], n);
  return n;
}

/*
** Return a pointer to bytes from the key or data.  The data returned
** is ephemeral.
*/
char *sqliteDbbeReadKey(DbbeCursor *pCursr, int offset){
  if( offset<0 || offset>=pCursr->key.dsize ) return "";
  return &pCursr->key.dptr[offset];
}
char *sqliteDbbeReadData(DbbeCursor *pCursr, int offset){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  if( offset<0 || offset>=pCursr->data.dsize ) return "";
  return &pCursr->data.dptr[offset];
}

/*
** Return the total number of bytes in either data or key.
*/
int sqliteDbbeKeyLength(DbbeCursor *pCursr){
  return pCursr->key.dsize;
}
int sqliteDbbeDataLength(DbbeCursor *pCursr){
  if( pCursr->readPending && pCursr->pFile && pCursr->pFile->dbf ){
    pCursr->data = gdbm_fetch(pCursr->pFile->dbf, pCursr->key);
    pCursr->readPending = 0;
  }
  return pCursr->data.dsize;
}

/*
** Make is so that the next call to sqliteNextKey() finds the first
** key of the table.
*/
int sqliteDbbeRewind(DbbeCursor *pCursr){
  pCursr->needRewind = 1;
  return SQLITE_OK;
}

/*
** Read the next key from the table.  Return 1 on success.  Return
** 0 if there are no more keys.
*/
int sqliteDbbeNextKey(DbbeCursor *pCursr){
  datum nextkey;
  int rc;
  if( pCursr==0 || pCursr->pFile==0 || pCursr->pFile->dbf==0 ){
    pCursr->readPending = 0;
    return 0;
  }
  if( pCursr->needRewind ){
    nextkey = gdbm_firstkey(pCursr->pFile->dbf);
    pCursr->needRewind = 0;
  }else{
    nextkey = gdbm_nextkey(pCursr->pFile->dbf, pCursr->key);
  }
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  pCursr->key = nextkey;
  if( pCursr->key.dptr ){
    pCursr->readPending = 1;
    rc = 1;
  }else{
    pCursr->needRewind = 1;
    pCursr->readPending = 0;
    rc = 0;
  }
  return rc;
}

/*
** Get a new integer key.
*/
int sqliteDbbeNew(DbbeCursor *pCursr){
  int iKey;
  datum key;
  int go = 1;
  int i;
  struct rc4 *pRc4;

  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return 1;
  pRc4 = &pCursr->pBe->rc4;
  while( go ){
    iKey = 0;
    for(i=0; i<4; i++){
      iKey = (iKey<<8) + rc4byte(pRc4);
    }
    key.dptr = (char*)&iKey;
    key.dsize = 4;
    go = gdbm_exists(pCursr->pFile->dbf, key);
  }
  return iKey;
}   

/*
** Write an entry into the table.  Overwrite any prior entry with the
** same key.
*/
int sqliteDbbePut(DbbeCursor *pCursr, int nKey,char *pKey,int nData,char *pData){
  datum data, key;
  int rc;
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  data.dsize = nData;
  data.dptr = pData;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_store(pCursr->pFile->dbf, key, data, GDBM_REPLACE);
  if( rc ) rc = SQLITE_ERROR;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  return rc;
}

/*
** Remove an entry from a table, if the entry exists.
*/
int sqliteDbbeDelete(DbbeCursor *pCursr, int nKey, char *pKey){
  datum key;
  int rc;
  datumClear(&pCursr->key);
  datumClear(&pCursr->data);
  if( pCursr->pFile==0 || pCursr->pFile->dbf==0 ) return SQLITE_ERROR;
  key.dsize = nKey;
  key.dptr = pKey;
  rc = gdbm_delete(pCursr->pFile->dbf, key);
  if( rc ) rc = SQLITE_ERROR;
  return rc;
}

/*
** Open a temporary file.  The file should be deleted when closed.
**

** This file defines the interface to the database backend (Dbbe).
**
** The database backend is designed to be as general as possible
** so that it can easily be replaced by a different backend.
** This library was originally designed to support the following
** backends: GDBM, NDBM, SDBM, Berkeley DB.
**
** $Id: dbbe.h,v 1.6 2000/06/21 13:59:11 drh Exp $
*/
#ifndef _SQLITE_DBBE_H_
#define _SQLITE_DBBE_H_
#include <stdio.h>

/*
** The database backend supports two opaque structures.  A Dbbe is
** a context for the entire set of tables forming a complete
** database.  A DbbeCursor is a pointer into a single single table.
**
** Note that at this level, the term "table" can mean either an
** SQL table or an SQL index.  In this module, a table stores a
** single arbitrary-length key and corresponding arbitrary-length
** data.  The differences between tables and indices, and the
** segregation of data into various fields or columns is handled
** by software at higher layers.
**
** The DbbeCursor structure holds some state information, such as
** the key and data from the last retrieval.  For this reason, 
** the backend must allow the creation of multiple independent
** DbbeCursor structures for each table in the database.
*/
typedef struct Dbbe Dbbe;
typedef struct DbbeCursor DbbeCursor;

/*
** The 18 interface routines.
*/

/* Open a complete database */
Dbbe *sqliteDbbeOpen(const char *zName, int write, int create, char **pzErr);

/* Close the whole database. */
void sqliteDbbeClose(Dbbe*);

/* Open a cursor into particular file of a previously opened database.
** Create the file if it doesn't already exist and writeable!=0.  zName
** is the base name of the file to be opened.  This routine will add
** an appropriate path and extension to the filename to locate the 
** actual file.
**
** If zName is 0 or "", then a temporary file is created that
** will be deleted when closed.
*/
int sqliteDbbeOpenCursor(Dbbe*, const char *zName, int writeable, DbbeCursor**);

/* Delete a table from the database */
void sqliteDbbeDropTable(Dbbe*, const char *zTableName);

/* Reorganize a table to speed access or reduce its disk usage */
void sqliteDbbeReorganizeTable(Dbbe*, const char *zTableName);

/* Close a cursor */
void sqliteDbbeCloseCursor(DbbeCursor*);

/* Fetch an entry from a table with the given key.  Return 1 if
** successful and 0 if no such entry exists.
*/
int sqliteDbbeFetch(DbbeCursor*, int nKey, char *pKey);

/* Return 1 if the given key is already in the table.  Return 0
** if it is not.
*/
int sqliteDbbeTest(DbbeCursor*, int nKey, char *pKey);

/* Retrieve the key or data used for the last fetch.  Only size
** bytes are read beginning with the offset-th byte.  The return
** value is the actual number of bytes read.
*/
int sqliteDbbeCopyKey(DbbeCursor*, int offset, int size, char *zBuf);
int sqliteDbbeCopyData(DbbeCursor*, int offset, int size, char *zBuf);

/* Retrieve the key or data.  The result is ephemeral.  In other words,
** the result is stored in a buffer that might be overwritten on the next
** call to any DBBE routine.  If the results are needed for longer than
** that, you must make a copy.
*/
char *sqliteDbbeReadKey(DbbeCursor*, int offset);
char *sqliteDbbeReadData(DbbeCursor*, int offset);

/* Return the length of the most recently fetched key or data. */
int sqliteDbbeKeyLength(DbbeCursor*);
int sqliteDbbeDataLength(DbbeCursor*);

/* Retrieve the next entry in the table.  The first key is retrieved
** the first time this routine is called, or after a call to
** sqliteDbbeRewind().  The return value is 1 if there is another
** entry, or 0 if there are no more entries. */
int sqliteDbbeNextKey(DbbeCursor*);

/* Make it so that the next call to sqliteDbbeNextKey() returns
** the first entry of the table. */
int sqliteDbbeRewind(DbbeCursor*);

/* Get a new integer key for this table. */
int sqliteDbbeNew(DbbeCursor*);

/* Write an entry into a table.  If another entry already exists with
** the same key, the old entry is discarded first.
*/
int sqliteDbbePut(DbbeCursor*, int nKey, char *pKey, int nData, char *pData);

/* Remove an entry from the table */
int sqliteDbbeDelete(DbbeCursor*, int nKey, char *pKey);

/* Open a file suitable for temporary storage */
int sqliteDbbeOpenTempFile(Dbbe*, FILE**);

/* Close a temporary file */
void sqliteDbbeCloseTempFile(Dbbe *, FILE *);

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle DELETE FROM statements.
**
** $Id: delete.c,v 1.6 2000/06/21 13:59:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process a DELETE FROM statement.
*/
void sqliteDeleteFrom(

        " may not be modified", 0);
      pParse->nErr++;
      goto delete_from_cleanup;
    }
  }
  pTab = pTabList->a[0].pTab;

  /* Resolve the column names in all the expressions.
  */
  if( pWhere ){
    sqliteExprResolveInSelect(pParse, pWhere);
    if( sqliteExprResolveIds(pParse, pTabList, pWhere) ){
      goto delete_from_cleanup;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){

  addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end, 0, 0);
  if( pTab->pIndex ){
    sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Fetch, base, 0, 0, 0);
    for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
      int j;
      sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
      for(j=0; j<pIdx->nColumn; j++){
        sqliteVdbeAddOp(v, OP_Field, base, pIdx->aiColumn[j], 0, 0);
      }
      sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_DeleteIdx, base+i, 0, 0, 0);
    }
  }
  sqliteVdbeAddOp(v, OP_Delete, base, 0, 0, 0);
  sqliteVdbeAddOp(v, OP_Goto, 0, addr, 0, 0);
  sqliteVdbeAddOp(v, OP_ListClose, 0, 0, 0, end);

delete_from_cleanup:
  sqliteIdListDelete(pTabList);
  sqliteExprDelete(pWhere);
  return;
}

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions.
**
** $Id: expr.c,v 1.18 2000/06/21 13:59:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** Walk an expression tree.  Return 1 if the expression is constant
** and 0 if it involves variables.
*/
static int isConstant(Expr *p){
  switch( p->op ){
    case TK_ID:
    case TK_COLUMN:
    case TK_DOT:
      return 0;
    default: {
      if( p->pLeft && !isConstant(p->pLeft) ) return 0;
      if( p->pRight && !isConstant(p->pRight) ) return 0;
      if( p->pList ){
        int i;

}

/*
** Walk the expression tree and process operators of the form:
**
**       expr IN (SELECT ...)
**
** These operators have to be processed before column names are
** resolved because each such operator increments pParse->nTab
** to reserve cursor numbers for its own use.  But pParse->nTab
** needs to be constant once we begin resolving column names.
**
** Actually, the processing of IN-SELECT is only started by this
** routine.  This routine allocates a cursor number to the IN-SELECT
** and then moves on.  The code generation is done by 
** sqliteExprResolveIds() which must be called afterwards.
*/
void sqliteExprResolveInSelect(Parse *pParse, Expr *pExpr){

      }
    }
  }
}

/*
** This routine walks an expression tree and resolves references to
** table columns.  Nodes of the form ID.ID or ID resolve into an
** index to the table in the table list and a column offset.  The opcode
** for such nodes is changed to TK_COLUMN.  The iTable value is changed
** to the index of the referenced table in pTabList plus the pParse->nTab
** value.  The iColumn value is changed to the index of the column of the 
** referenced table.
**
** We also check for instances of the IN operator.  IN comes in two
** forms:
**
**           expr IN (exprlist)
** and
**           expr IN (SELECT ...)
**
** The first form is handled by creating a set holding the list
** of allowed values.  The second form causes the SELECT to generate 
** a temporary table.
**
** This routine also looks for scalar SELECTs that are part of an expression.
** If it finds any, it generates code to write the value of that select
** into a memory cell.
**
** Unknown columns or tables provoke an error.  The function returns
** the number of errors seen and leaves an error message on pParse->zErrMsg.
*/
int sqliteExprResolveIds(Parse *pParse, IdList *pTabList, Expr *pExpr){
  if( pExpr==0 ) return 0;
  switch( pExpr->op ){
    /* A lone identifier */
    case TK_ID: {
      int cnt = 0;   /* Number of matches */
      int i;         /* Loop counter */
      char *z = sqliteStrNDup(pExpr->token.z, pExpr->token.n);
      for(i=0; i<pTabList->nId; i++){
        int j;
        Table *pTab = pTabList->a[i].pTab;
        if( pTab==0 ) continue;
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, z)==0 ){
            cnt++;
            pExpr->iTable = i + pParse->nTab;
            pExpr->iColumn = j;
          }
        }
      }
      sqliteFree(z);
      if( cnt==0 ){
        sqliteSetNString(&pParse->zErrMsg, "no such column: ", -1,  
          pExpr->token.z, pExpr->token.n, 0);
        pParse->nErr++;
        return 1;
      }else if( cnt>1 ){
        sqliteSetNString(&pParse->zErrMsg, "ambiguous column name: ", -1,  
          pExpr->token.z, pExpr->token.n, 0);
        pParse->nErr++;
        return 1;
      }
      pExpr->op = TK_COLUMN;
      break; 
    }
  
    /* A table name and column name:  ID.ID */
    case TK_DOT: {
      int cnt = 0;             /* Number of matches */
      int i;                   /* Loop counter */
      Expr *pLeft, *pRight;    /* Left and right subbranches of the expr */
      char *zLeft, *zRight;    /* Text of an identifier */

      pLeft = pExpr->pLeft;

          zTab = pTab->zName;
        }
        if( sqliteStrICmp(zTab, zLeft)!=0 ) continue;
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
            cnt++;
            pExpr->iTable = i + pParse->nTab;
            pExpr->iColumn = j;
          }
        }
      }
      sqliteFree(zLeft);
      sqliteFree(zRight);
      if( cnt==0 ){
        sqliteSetNString(&pParse->zErrMsg, "no such column: ", -1,  
          pLeft->token.z, pLeft->token.n, ".", 1, 
          pRight->token.z, pRight->token.n, 0);
        pParse->nErr++;
        return 1;
      }else if( cnt>1 ){
        sqliteSetNString(&pParse->zErrMsg, "ambiguous column name: ", -1,  
          pLeft->token.z, pLeft->token.n, ".", 1,
          pRight->token.z, pRight->token.n, 0);
        pParse->nErr++;
        return 1;
      }
      sqliteExprDelete(pLeft);
      pExpr->pLeft = 0;
      sqliteExprDelete(pRight);
      pExpr->pRight = 0;
      pExpr->op = TK_COLUMN;
      break;
    }

    case TK_IN: {
      Vdbe *v = sqliteGetVdbe(pParse);
      if( v==0 ) return 1;
      if( sqliteExprResolveIds(pParse, pTabList, pExpr->pLeft) ){

      }
      break;
    }

    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.
      */
      pExpr->iColumn = pParse->nMem++;
      if( sqliteSelect(pParse, pExpr->pSelect, SRT_Mem, pExpr->iColumn) ){
        return 1;
      }
      break;
    }

    /* For all else, just recursively walk the tree */
    default: {

      int id = sqliteFuncId(&pExpr->token);
      int n = pExpr->pList ? pExpr->pList->nExpr : 0;
      int no_such_func = 0;
      int too_many_args = 0;
      int too_few_args = 0;
      int is_agg = 0;
      int i;
      pExpr->iColumn = id;
      switch( id ){
        case FN_Unknown: { 
          no_such_func = 1;
          break;
        }
        case FN_Count: { 
          no_such_func = !allowAgg;

    case TK_ISNULL:   op = OP_IsNull;   break;
    case TK_NOTNULL:  op = OP_NotNull;  break;
    case TK_NOT:      op = OP_Not;      break;
    case TK_UMINUS:   op = OP_Negative; break;
    default: break;
  }
  switch( pExpr->op ){
    case TK_COLUMN: {
      if( pParse->useAgg ){
        sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg, 0, 0);
      }else{
        sqliteVdbeAddOp(v, OP_Field, pExpr->iTable, pExpr->iColumn, 0, 0);
      }
      break;
    }
    case TK_INTEGER: {
      int i = atoi(pExpr->token.z);
      sqliteVdbeAddOp(v, OP_Integer, i, 0, 0, 0);
      break;

      dest = sqliteVdbeCurrentAddr(v) + 2;
      sqliteVdbeAddOp(v, op, 0, dest, 0, 0);
      sqliteVdbeAddOp(v, OP_AddImm, -1, 0, 0, 0);
      break;
    }
    case TK_AGG_FUNCTION: {
      sqliteVdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg, 0, 0);
      if( pExpr->iColumn==FN_Avg ){
        assert( pParse->iAggCount>=0 && pParse->iAggCount<pParse->nAgg );
        sqliteVdbeAddOp(v, OP_AggGet, 0, pParse->iAggCount, 0, 0);
        sqliteVdbeAddOp(v, OP_Divide, 0, 0, 0, 0);
      }
      break;
    }
    case TK_FUNCTION: {
      int id = pExpr->iColumn;
      int op;
      int i;
      ExprList *pList = pExpr->pList;
      if( id==FN_Fcnt ){
        sqliteVdbeAddOp(v, OP_Fcnt, 0, 0, 0, 0);
        break;
      }
      op = id==FN_Min ? OP_Min : OP_Max;
      for(i=0; i<pList->nExpr; i++){
        sqliteExprCode(pParse, pList->a[i].pExpr);
        if( i>0 ){
          sqliteVdbeAddOp(v, op, 0, 0, 0, 0);
        }
      }
      break;
    }
    case TK_SELECT: {
      sqliteVdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0, 0, 0);
      break;
    }
    case TK_IN: {
      int addr;
      sqliteVdbeAddOp(v, OP_Integer, 1, 0, 0, 0);
      sqliteExprCode(pParse, pExpr->pLeft);
      addr = sqliteVdbeCurrentAddr(v);

int sqliteExprAnalyzeAggregates(Parse *pParse, Expr *pExpr){
  int i;
  AggExpr *aAgg;
  int nErr = 0;

  if( pExpr==0 ) return 0;
  switch( pExpr->op ){
    case TK_COLUMN: {
      aAgg = pParse->aAgg;
      for(i=0; i<pParse->nAgg; i++){
        if( aAgg[i].isAgg ) continue;
        if( aAgg[i].pExpr->iTable==pExpr->iTable
         && aAgg[i].pExpr->iColumn==pExpr->iColumn ){
          break;
        }
      }
      if( i>=pParse->nAgg ){
        i = appendAggInfo(pParse);
        if( i<0 ) return 1;
        pParse->aAgg[i].isAgg = 0;
        pParse->aAgg[i].pExpr = pExpr;
      }
      pExpr->iAgg = i;
      break;
    }
    case TK_AGG_FUNCTION: {
      if( pExpr->iColumn==FN_Count || pExpr->iColumn==FN_Avg ){
        if( pParse->iAggCount>=0 ){
          i = pParse->iAggCount;
        }else{
          i = appendAggInfo(pParse);
          if( i<0 ) return 1;
          pParse->aAgg[i].isAgg = 1;
          pParse->aAgg[i].pExpr = 0;
          pParse->iAggCount = i;
        }
        if( pExpr->iColumn==FN_Count ){
          pExpr->iAgg = i;
          break;
        }
      }
      aAgg = pParse->aAgg;
      for(i=0; i<pParse->nAgg; i++){
        if( !aAgg[i].isAgg ) continue;

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements.
**
** $Id: insert.c,v 1.11 2000/06/21 13:59:12 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)
**    insert into TABLE (IDLIST) select
**
** The IDLIST following the table name is always optional.  If omitted,
** then a list of all columns for the table is substituted.  The IDLIST
** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
**
** The pList parameter holds EXPRLIST in the first form of the INSERT
** statement above, and pSelect is NULL.  For the second form, pList is
** NULL and pSelect is a pointer to the select statement used to generate
** data for the insert.
*/
void sqliteInsert(
  Parse *pParse,        /* Parser context */
  Token *pTableName,    /* Name of table into which we are inserting */
  ExprList *pList,      /* List of values to be inserted */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  IdList *pColumn       /* Column names corresponding to IDLIST. */
){
  Table *pTab;          /* The table to insert into */
  char *zTab;           /* Name of the table into which we are inserting */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int srcTab;           /* Date comes from this temporary cursor if >=0 */
  int nColumn;          /* Number of columns in the data */
  int base;             /* First available cursor */
  int iCont, iBreak;    /* Beginning and end of the loop over srcTab */

  /* Locate the table into which we will be inserting new information.
  */
  zTab = sqliteTableNameFromToken(pTableName);
  pTab = sqliteFindTable(pParse->db, zTab);

  if( pSelect ){
    int rc;
    srcTab = pParse->nTab++;
    sqliteVdbeAddOp(v, OP_Open, srcTab, 1, 0, 0);
    rc = sqliteSelect(pParse, pSelect, SRT_Table, srcTab);
    if( rc ) goto insert_cleanup;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
  }else{
    srcTab = -1;
    assert( pList );
    nColumn = pList->nExpr;
  }

  /* Make sure the number of columns in the source data matches the number
  ** of columns to be inserted into the table.
  */
  if( pColumn==0 && nColumn!=pTab->nCol ){
    char zNum1[30];
    char zNum2[30];
    sprintf(zNum1,"%d", nColumn);
    sprintf(zNum2,"%d", pTab->nCol);
    sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName,
       " has ", zNum2, " columns but ",
       zNum1, " values were supplied", 0);
    pParse->nErr++;
    goto insert_cleanup;
  }
  if( pColumn!=0 && nColumn!=pColumn->nId ){
    char zNum1[30];
    char zNum2[30];
    sprintf(zNum1,"%d", nColumn);
    sprintf(zNum2,"%d", pColumn->nId);
    sqliteSetString(&pParse->zErrMsg, zNum1, " values for ",
       zNum2, " columns", 0);
    pParse->nErr++;
    goto insert_cleanup;
  }

  /* If the INSERT statement included an IDLIST term, then make sure
  ** all elements of the IDLIST really are columns of the table and 
  ** remember the column indices.
  */
  if( pColumn ){
    for(i=0; i<pColumn->nId; i++){
      pColumn->a[i].idx = -1;
    }
    for(i=0; i<pColumn->nId; i++){
      for(j=0; j<pTab->nCol; j++){
        if( sqliteStrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
          pColumn->a[i].idx = j;
          break;
        }
      }
      if( j>=pTab->nCol ){
        sqliteSetString(&pParse->zErrMsg, "table ", pTab->zName,
           " has no column named ", pColumn->a[i].zName, 0);
        pParse->nErr++;
        goto insert_cleanup;
      }
    }
  }

  /* Open cursors into the table that is received the new data and

  /* Create a new entry in the table and fill it with data.
  */
  sqliteVdbeAddOp(v, OP_New, 0, 0, 0, 0);
  if( pTab->pIndex ){
    sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
  }
  for(i=0; i<pTab->nCol; i++){
    if( pColumn==0 ){
      j = i;
    }else{
      for(j=0; j<pColumn->nId; j++){
        if( pColumn->a[j].idx==i ) break;
      }
    }
    if( pColumn && j>=pColumn->nId ){
      char *zDflt = pTab->aCol[i].zDflt;
      if( zDflt==0 ){
        sqliteVdbeAddOp(v, OP_Null, 0, 0, 0, 0);
      }else{
        sqliteVdbeAddOp(v, OP_String, 0, 0, zDflt, 0);
      }
    }else if( srcTab>=0 ){

  /* Create appropriate entries for the new data row in all indices
  ** of the table.
  */
  for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
    if( pIdx->pNext ){
      sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
    }
    for(i=0; i<pIdx->nColumn; i++){
      int idx = pIdx->aiColumn[i];
      if( pColumn==0 ){
        j = idx;
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==idx ) break;
        }
      }
      if( pColumn && j>=pColumn->nId ){
        char *zDflt = pTab->aCol[idx].zDflt;
        if( zDflt==0 ){
          sqliteVdbeAddOp(v, OP_Null, 0, 0, 0, 0);
        }else{
          sqliteVdbeAddOp(v, OP_String, 0, 0, zDflt, 0);
        }
      }else if( srcTab>=0 ){
        sqliteVdbeAddOp(v, OP_Field, srcTab, idx, 0, 0); 
      }else{
        sqliteExprCode(pParse, pList->a[j].pExpr);
      }
    }
    sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_PutIdx, idx+base, 0, 0, 0);
  }

  /* The bottom of the loop, if the data source is a SELECT statement
  */
  if( srcTab>=0 ){
    sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
    sqliteVdbeAddOp(v, OP_Noop, 0, 0, 0, iBreak);
  }

insert_cleanup:
  if( pList ) sqliteExprListDelete(pList);
  if( pSelect ) sqliteSelectDelete(pSelect);
  sqliteIdListDelete(pColumn);
}

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.13 2000/06/21 13:59:12 drh Exp $
*/
#include "sqliteInt.h"

/*
** This is the callback routine for the code that initializes the
** database.  Each callback contains text of a CREATE TABLE or
** CREATE INDEX statement that must be parsed to yield the internal

  **        type       text,    --  Either "table" or "index"
  **        name       text,    --  Name of table or index
  **        tbl_name   text,    --  Associated table 
  **        sql        text     --  The CREATE statement for this object
  **    );
  **
  ** The sqlite_master table contains a single entry for each table
  ** and each index.  The "type" column tells whether the entry is
  ** a table or index.  The "name" column is the name of the object.
  ** The "tbl_name" is the name of the associated table.  For tables,
  ** the tbl_name column is always the same as name.  For indices, the
  ** tbl_name column contains the name of the table that the index
  ** indexes.  Finally, the "sql" column contains the complete text of
  ** the CREATE TABLE or CREATE INDEX statement that originally created
  ** the table or index.
  **
  ** The following program invokes its callback on the SQL for each
  ** table then goes back and invokes the callback on the
  ** SQL for each index.  The callback will invoke the
  ** parser to build the internal representation of the

**
*************************************************************************
** 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 1.23 2000/06/21 13:59:12 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetString(&pParse->zErrMsg,"syntax error",0);
  pParse->sErrToken = TOKEN;

input ::= cmdlist.

// These are extra tokens used by the lexer but never seen by the
// parser.  We put them in a rule so that the parser generator will
// add them to the parse.h output file.
//
input ::= END_OF_FILE ILLEGAL SPACE UNCLOSED_STRING COMMENT FUNCTION
          UMINUS COLUMN AGG_FUNCTION.

// A list of commands is zero or more commands
//
cmdlist ::= ecmd.
cmdlist ::= cmdlist SEMI ecmd.
ecmd ::= explain cmd.  {sqliteExec(pParse);}
ecmd ::= cmd.          {sqliteExec(pParse);}

cmd ::= UPDATE id(X) SET setlist(Y) where_opt(Z).
    {sqliteUpdate(pParse,&X,Y,Z);}

setlist(A) ::= id(X) EQ expr(Y) COMMA setlist(Z).
    {A = sqliteExprListAppend(Z,Y,&X);}
setlist(A) ::= id(X) EQ expr(Y).   {A = sqliteExprListAppend(0,Y,&X);}

cmd ::= INSERT INTO id(X) inscollist_opt(F) VALUES LP itemlist(Y) RP.
               {sqliteInsert(pParse, &X, Y, 0, F);}
cmd ::= INSERT INTO id(X) inscollist_opt(F) select(S).
               {sqliteInsert(pParse, &X, 0, S, F);}


%type itemlist {ExprList*}
%destructor itemlist {sqliteExprListDelete($$);}
%type item {Expr*}
%destructor item {sqliteExprDelete($$);}

item(A) ::= MINUS FLOAT(X).  {
  A = sqliteExpr(TK_UMINUS, 0, 0, 0);
  A->pLeft = sqliteExpr(TK_FLOAT, 0, 0, &X);
}
item(A) ::= STRING(X).       {A = sqliteExpr(TK_STRING, 0, 0, &X);}
item(A) ::= NULL.            {A = sqliteExpr(TK_NULL, 0, 0, 0);}

%type inscollist_opt {IdList*}
%destructor inscollist_opt {sqliteIdListDelete($$);}
%type inscollist {IdList*}
%destructor inscollist {sqliteIdListDelete($$);}

inscollist_opt(A) ::= .                      {A = 0;}
inscollist_opt(A) ::= LP inscollist(X) RP.   {A = X;}
inscollist(A) ::= inscollist(X) COMMA id(Y). {A = sqliteIdListAppend(X,&Y);}
inscollist(A) ::= id(Y).                     {A = sqliteIdListAppend(0,&Y);}

%left OR.
%left AND.
%right NOT.
%left EQ NE ISNULL NOTNULL IS LIKE GLOB BETWEEN IN.
%left GT GE LT LE.
%left PLUS MINUS.

**   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 1.25 2000/06/21 13:59:12 drh Exp $
*/
#include "sqliteInt.h"

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

}

/*
** 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 nColumn
** 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 nColumn,            /* Number of columns 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 columns.
  */
  if( pEList ){
    for(i=0; i<pEList->nExpr; i++){
      sqliteExprCode(pParse, pEList->a[i].pExpr);
    }
    nColumn = pEList->nExpr;
  }else{
    for(i=0; i<nColumn; 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 there is an ORDER BY clause, then store the results
  ** in a sorter.
  */
  if( pOrderBy ){
    char *zSortOrder;
    sqliteVdbeAddOp(v, OP_SortMakeRec, nColumn, 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].sortOrder ? '-' : '+';
      sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
    }
    zSortOrder[pOrderBy->nExpr] = 0;
    sqliteVdbeAddOp(v, OP_SortMakeKey, pOrderBy->nExpr, 0, zSortOrder, 0);
    sqliteFree(zSortOrder);
    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, nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_String, iParm, 0, "", 0);
    sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
  }else 

  /* Store the result as data using a unique key.
  */
  if( eDest==SRT_Table ){
    sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_New, iParm, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Pull, 1, 0, 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 ){
    sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Delete, 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( nColumn==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 ){
    assert( nColumn==1 );
    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, nColumn, 0, 0, 0);
  }
  return 0;
}

/*
** If the inner loop was generated using a non-null pOrderBy argument,
** then the results were placed in a sorter.  After the loop is terminated
** we need to run the sorter and output the results.  The following
** routine generates the code needed to do that.
*/
static void generateSortTail(Vdbe *v, int nColumn){
  int end = sqliteVdbeMakeLabel(v);
  int addr;
  sqliteVdbeAddOp(v, OP_Sort, 0, 0, 0, 0);
  addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end, 0, 0);
  sqliteVdbeAddOp(v, OP_SortCallback, nColumn, 0, 0, 0);
  sqliteVdbeAddOp(v, OP_Goto, 0, addr, 0, 0);
  sqliteVdbeAddOp(v, OP_SortClose, 0, 0, 0, end);
}

/*
** Generate code that will tell the VDBE how many columns there
** are in the result and the name for each column.  This information

    Expr *p;
    if( pEList->a[i].zName ){
      char *zName = pEList->a[i].zName;
      sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
      continue;
    }
    p = pEList->a[i].pExpr;
    if( p->op!=TK_COLUMN || pTabList==0 ){
      char zName[30];
      sprintf(zName, "column%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->iColumn].zName, 0);
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
        sqliteFree(zName);
      }else{
        Table *pTab = pTabList->a[0].pTab;
        char *zName = pTab->aCol[p->iColumn].zName;
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
      }
    }
  }
}

/*

  }
  return z;
}

/*
** For the given SELECT statement, do two things.
**
**    (1)  Fill in the pTabList->a[].pTab fields in the IdList that 
**         defines the set of tables that should be scanned.
**
**    (2)  If the columns to be extracted variable (pEList) is NULL
**         (meaning that a "*" was used in the SQL statement) then
**         create a fake pEList containing the names of all columns
**         of all tables.
**
** Return 0 on success.  If there are problems, leave an error message

  }
  return 0;
}

/*
** This routine associates entries in an ORDER BY expression list with
** columns in a result.  For each ORDER BY expression, the opcode of
** the top-level node is changed to TK_COLUMN and the iColumn value of
** the top-level node is filled in with column number and the iTable
** value of the top-level node is filled with iTable parameter.
**
** If there are prior SELECT clauses, they are processed first.  A match
** in an earlier SELECT takes precedence over a later SELECT.
**
** Any entry that does not match is flagged as an error.  The number

        }
        sqliteFree(zLabel);
      }
      if( match==0 && sqliteExprCompare(pE, pEList->a[j].pExpr) ){
        match = 1;
      }
      if( match ){
        pE->op = TK_COLUMN;
        pE->iColumn = j;
        pE->iTable = iTable;
        pOrderBy->a[i].done = 1;
        break;
      }
    }
    if( !match && mustComplete ){
      char zBuf[30];

  int eDest,             /* One of: SRT_Callback Mem Set Union Except */
  int iParm              /* Save result in this memory location, if >=0 */
){
  int i;
  WhereInfo *pWInfo;
  Vdbe *v;
  int isAgg = 0;         /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns 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 */

  ** errors before this routine starts.
  */
  if( pParse->nErr>0 ) return 1;
  sqliteParseInfoReset(pParse);

  /* Look up every table in the table list and create an appropriate
  ** columnlist in pEList if there isn't one already.  (The parser leaves
  ** a NULL in the p->pEList if the SQL said "SELECT * FROM ...")
  */
  if( fillInColumnList(pParse, p) ){
    return 1;
  }
  pEList = p->pEList;

  /* Allocate a temporary table to use for the DISTINCT set, if

  }
  if( pHaving ) sqliteExprResolveInSelect(pParse, pHaving);

  /* At this point, we should have allocated all the cursors that we
  ** need to handle subquerys and temporary tables.  From here on we
  ** are committed to keeping the same value for pParse->nTab.
  **
  ** Resolve the column names and do a semantics check on all the expressions.
  */
  for(i=0; i<pEList->nExpr; i++){
    if( sqliteExprResolveIds(pParse, pTabList, pEList->a[i].pExpr) ){
      return 1;
    }
    if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &isAgg) ){
      return 1;

        sqliteVdbeAddOp(v, OP_AggIncr, 1, i, 0, 0);
        continue;
      }
      assert( pE->op==TK_AGG_FUNCTION );
      assert( pE->pList!=0 && pE->pList->nExpr==1 );
      sqliteExprCode(pParse, pE->pList->a[0].pExpr);
      sqliteVdbeAddOp(v, OP_AggGet, 0, i, 0, 0);
      switch( pE->iColumn ){
        case FN_Min:  op = OP_Min;   break;
        case FN_Max:  op = OP_Max;   break;
        case FN_Avg:  op = OP_Add;   break;
        case FN_Sum:  op = OP_Add;   break;
      }
      sqliteVdbeAddOp(v, op, 0, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_AggSet, 0, i, 0, 0);

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains code to implement the "sqlite" command line
** utility for accessing SQLite databases.
**
** $Id: shell.c,v 1.15 2000/06/21 13:59:12 drh Exp $
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "sqlite.h"
#include <unistd.h>
#include <ctype.h>

  char separator[20];    /* Separator character for MODE_List */
  int colWidth[30];      /* Width of each column when in column mode */
};

/*
** These are the allowed modes.
*/
#define MODE_Line     0  /* One column per line.  Blank line between records */
#define MODE_Column   1  /* One record per line in neat columns */
#define MODE_List     2  /* One record per line with a separator */
#define MODE_Html     3  /* Generate an XHTML table */
#define MODE_Insert   4  /* Generate SQL "insert" statements */

/*
** Number of elements in an array

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.25 2000/06/21 13:59:12 drh Exp $
*/
#include "sqlite.h"
#include "dbbe.h"
#include "vdbe.h"
#include "parse.h"
#include <gdbm.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/*
** If memory allocation problems are found, recompile with
**
**      -DMEMORY_DEBUG=1
**
** to enable some sanity checking on malloc() and free().  To
** check for memory leaks, recompile with
**
**      -DMEMORY_DEBUG=2
**
** and a line of text will be written to standard error for
** each malloc() and free().  This output can be analyzed
** by an AWK script to determine if there are any leaks.
*/
#ifdef MEMORY_DEBUG
# define sqliteMalloc(X)    sqliteMalloc_(X,__FILE__,__LINE__)
# define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
# define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
# define sqliteStrDup(X)    sqliteStrDup_(X,__FILE__,__LINE__)
# define sqliteStrNDup(X,Y) sqliteStrNDup_(X,Y,__FILE__,__LINE__)
  void sqliteStrRealloc(char**);

#ifdef MEMORY_DEBUG
int sqlite_nMalloc;         /* Number of sqliteMalloc() calls */
int sqlite_nFree;           /* Number of sqliteFree() calls */
int sqlite_iMallocFail;     /* Fail sqliteMalloc() after this many calls */
#endif

/*
** The number of entries in the in-memory hash array holding the
** database schema.
*/
#define N_HASH        51

/*
** Name of the master database table.  The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/
#define MASTER_NAME   "sqlite_master"

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    (sizeof(X)/sizeof(X[0]))

/*
** Integer identifiers for built-in SQL functions.
*/
#define FN_Unknown    0
#define FN_Count      1
#define FN_Min        2
#define FN_Max        3
#define FN_Sum        4
#define FN_Avg        5

  Dbbe *pBe;                 /* The backend driver */
  int flags;                 /* Miscellanous flags */
  Table *apTblHash[N_HASH];  /* All tables of the database */
  Index *apIdxHash[N_HASH];  /* All indices of the database */
};

/*
** Possible values for the sqlite.flags.
*/
#define SQLITE_VdbeTrace    0x00000001
#define SQLITE_Initialized  0x00000002

/*
** information about each column of an SQL table is held in an instance
** of this structure.
*/
struct Column {
  char *zName;     /* Name of this column */
  char *zDflt;     /* Default value of this column */
  int notNull;     /* True if there is a NOT NULL constraint */
};

/*
** Each SQL table is represented in memory by
** an instance of the following structure.
*/
struct Table {
  char *zName;     /* Name of the table */
  Table *pHash;    /* Next table with same hash on zName */
  int nCol;        /* Number of columns in this table */
  Column *aCol;    /* Information about each column */
  int readOnly;    /* True if this table should not be written by the user */
  Index *pIndex;   /* List of SQL indexes on this table. */
};

/*
** Each SQL index is represented in memory by and
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure.  For example, suppose
** we have the following table and index:
**
**     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
**     CREATE INDEX Ex2 ON Ex1(c3,c1);
**
** In the Table structure describing Ex1, nCol==3 because there are
** three columns in the table.  In the Index structure describing
** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
** The second column to be indexed (c1) has an index of 0 in
** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
*/
struct Index {
  char *zName;     /* Name of this index */
  Index *pHash;    /* Next index with the same hash on zName */
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  Table *pTable;   /* The SQL table being indexed */
  int isUnique;    /* True if keys must all be unique */
  Index *pNext;    /* The next index associated with the same table */
};

/*
** Each token coming out of the lexer is an instance of
** this structure.
*/
struct Token {
  char *z;      /* Text of the token */
  int n;        /* Number of characters in this token */
};

/*
** Each node of an expression in the parse tree is an instance
** of this structure
*/
struct Expr {
  int op;                /* Operation performed by this node */
  Expr *pLeft, *pRight;  /* Left and right subnodes */
  ExprList *pList;       /* A list of expressions used as a function argument */
  Token token;           /* An operand token */
  int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
                         ** iColumn-th field of the iTable-th table.  When
                         ** op==TK_FUNCTION, iColumn holds the function id */
  int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
                         ** result from the iAgg-th element of the aggregator */
  Select *pSelect;       /* When the expression is a sub-select */
};

/*
** A list of expressions.  Each expression may optionally have a
** name.  An expr/name combination can be used in several ways, such
** as the list of "expr AS ID" fields following a "SELECT" or in the

** A list of identifiers.
*/
struct IdList {
  int nId;         /* Number of identifiers on the list */
  struct {
    char *zName;      /* Text of the identifier. */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    int idx;          /* Index in some Table.aCol[] of a column named zName */
  } *a;            /* One entry for each identifier on the list */
};

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of

  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 in a compound select statement */
};

/*
** 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 */

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.8 2000/06/21 13:59:12 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process an UPDATE statement.
*/
void sqliteUpdate(

  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Vdbe *v;               /* The virtual database engine */
  Index *pIdx;           /* For looping over indices */
  int nIdx;              /* Number of indices that need updating */
  int base;              /* Index of first available table cursor */
  Index **apIdx = 0;     /* An array of indices that need updating too */
  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
                         ** an expression for the i-th column of the table.
                         ** aXRef[i]==-1 if the i-th column is not changed. */

  /* Locate the table which we want to update.  This table has to be
  ** put in an IdList structure because some of the subroutines we
  ** will be calling are designed to work with multiple tables and expect
  ** an IdList* parameter instead of just a Table* parameger.
  */
  pTabList = sqliteIdListAppend(0, pTableName);

    }
  }
  pTab = pTabList->a[0].pTab;
  aXRef = sqliteMalloc( sizeof(int) * pTab->nCol );
  if( aXRef==0 ) goto update_cleanup;
  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;

  /* Resolve the column names in all the expressions in both the
  ** WHERE clause and in the new values.  Also find the column index
  ** for each column to be updated in the pChanges array.
  */
  if( pWhere ){
    sqliteExprResolveInSelect(pParse, pWhere);
  }
  for(i=0; i<pChanges->nExpr; i++){
    sqliteExprResolveInSelect(pParse, pChanges->a[i].pExpr);
  }

    for(j=0; j<pTab->nCol; j++){
      if( sqliteStrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
        aXRef[j] = i;
        break;
      }
    }
    if( j>=pTab->nCol ){
      sqliteSetString(&pParse->zErrMsg, "no such column: ", 
         pChanges->a[i].zName, 0);
      pParse->nErr++;
      goto update_cleanup;
    }
  }

  /* Allocate memory for the array apIdx[] and fill it pointers to every
  ** index that needs to be updated.  Indices only need updating if their
  ** key includes one of the columns named in pChanges.
  */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    for(i=0; i<pIdx->nColumn; i++){
      if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
    }
    if( i<pIdx->nColumn ) nIdx++;
  }
  apIdx = sqliteMalloc( sizeof(Index*) * nIdx );
  if( apIdx==0 ) goto update_cleanup;
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    for(i=0; i<pIdx->nColumn; i++){
      if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
    }
    if( i<pIdx->nColumn ) apIdx[nIdx++] = pIdx;
  }

  /* Begin generating code.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) goto update_cleanup;

  base = pParse->nTab;
  sqliteVdbeAddOp(v, OP_Open, base, 1, pTab->zName, 0);
  for(i=0; i<nIdx; i++){
    sqliteVdbeAddOp(v, OP_Open, base+i+1, 1, apIdx[i]->zName, 0);
  }

  /* Loop over every record that needs updating.  We have to load
  ** the old data for each record to be updated because some columns
  ** might not change and we will need to copy the old value.
  ** Also, the old data is needed to delete the old index entires.
  */
  end = sqliteVdbeMakeLabel(v);
  addr = sqliteVdbeAddOp(v, OP_ListRead, 0, end, 0, 0);
  sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
  sqliteVdbeAddOp(v, OP_Fetch, base, 0, 0, 0);

  /* Delete the old indices for the current record.
  */
  for(i=0; i<nIdx; i++){
    sqliteVdbeAddOp(v, OP_Dup, 0, 0, 0, 0);
    pIdx = apIdx[i];
    for(j=0; j<pIdx->nColumn; j++){
      sqliteVdbeAddOp(v, OP_Field, base, pIdx->aiColumn[j], 0, 0);
    }
    sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_DeleteIdx, base+i+1, 0, 0, 0);
  }

  /* Compute a completely new data for this record.  
  */
  for(i=0; i<pTab->nCol; i++){
    j = aXRef[i];
    if( j<0 ){
      sqliteVdbeAddOp(v, OP_Field, base, i, 0, 0);
    }else{
      sqliteExprCode(pParse, pChanges->a[j].pExpr);
    }
  }

  /* Insert new index entries that correspond to the new data
  */
  for(i=0; i<nIdx; i++){
    sqliteVdbeAddOp(v, OP_Dup, pTab->nCol, 0, 0, 0); /* The KEY */
    pIdx = apIdx[i];
    for(j=0; j<pIdx->nColumn; j++){
      sqliteVdbeAddOp(v, OP_Dup, j+pTab->nCol-pIdx->aiColumn[j], 0, 0, 0);
    }
    sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_PutIdx, base+i+1, 0, 0, 0);
  }

  /* Write the new data back into the database.
  */
  sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0, 0, 0);
  sqliteVdbeAddOp(v, OP_Put, base, 0, 0, 0);

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.13 2000/06/21 13:59:12 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

#ifdef MEMORY_DEBUG

    h = h<<3 ^ h ^ UpperToLower[c];
  }
  if( h<0 ) h = -h;
  return h;
}

/*
** Some systems have stricmp().  Others have strcasecmp().  Because
** there is no consistency, we will define our own.
*/
int sqliteStrICmp(const char *zLeft, const char *zRight){
  register unsigned char *a, *b;
  a = (unsigned char *)zLeft;
  b = (unsigned char *)zRight;
  while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }

** 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 1.34 2000/06/21 13:59:13 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;

/*
** A cursor is a pointer into a database file.  The database file
** can represent either an SQL table or an SQL index.  Each file is
** a bag of key/data pairs.  The cursor can loop over all key/data
** pairs (in an arbitrary order) or it can retrieve a particular
** key/data pair given a copy of the key.
** 
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct Cursor {
  DbbeCursor *pCursor;  /* The cursor 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 Cursor Cursor;

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

#define STK_Null      0x0001   /* Value is NULL */
#define STK_Str       0x0002   /* Value is a string */
#define STK_Int       0x0004   /* Value is an integer */
#define STK_Real      0x0008   /* Value is a real number */
#define STK_Dyn       0x0010   /* Need to call sqliteFree() on zStack[*] */

/*
** An Agg structure describes an Aggregator.  Each Agg consists of
** zero or more Aggregator elements (AggElem).  Each AggElem contains
** a key and one or more values.  The values are used in processing
** aggregate functions in a SELECT.  The key is used to implement
** the GROUP BY clause of a select.
*/
typedef struct Agg Agg;
typedef struct AggElem AggElem;
struct Agg {
  int nMem;              /* Number of values stored in each AggElem */
  AggElem *pCurrent;     /* The AggElem currently in focus */
  int nElem;             /* The number of AggElems */
  int nHash;             /* Number of slots in apHash[] */
  AggElem **apHash;      /* A hash array for looking up AggElems by zKey */
  AggElem *pFirst;       /* A list of all AggElems */
};
struct AggElem {
  char *zKey;            /* The key to this AggElem */
  AggElem *pHash;        /* Next AggElem with the same hash on zKey */
  AggElem *pNext;        /* Next AggElem in a list of them all */
  Mem aMem[1];           /* The values for this AggElem */
};

/*
** A Set structure is used for quick testing to see if a value
** is part of a small set.  Sets are used to implement code like
** this:
**            x.y IN ('hi','hoo','hum')
*/
typedef struct Set Set;
typedef struct SetElem SetElem;
struct Set {
  SetElem *pAll;         /* All elements of this set */
  SetElem *apHash[41];   /* A hash array for all elements in this set */
};
struct SetElem {
  SetElem *pHash;        /* Next element with the same hash on zKey */
  SetElem *pNext;        /* Next element in a list of them all */
  char zKey[1];          /* Value of this key */
};

  int nLabelAlloc;    /* Number of slots allocated in aLabel[] */
  int *aLabel;        /* Space to hold the labels */
  int tos;            /* Index of top of stack */
  int nStackAlloc;    /* Size of the stack */
  Stack *aStack;      /* The operand stack, except string values */
  char **zStack;      /* Text or binary values of the stack */
  char **azColName;   /* Becomes the 4th parameter to callbacks */
  int nCursor;        /* Number of slots in aCsr[] */
  Cursor *aCsr;       /* On element of this array for each open cursor */
  int nList;          /* Number of slots in apList[] */
  FILE **apList;      /* An open file for each list */
  int nSort;          /* Number of slots in apSort[] */
  Sorter **apSort;    /* An open sorter list */
  FILE *pFile;        /* At most one open file handler */
  int nField;         /* Number of file fields */
  char **azField;     /* Data for each file field */

    sqliteFree(pElem);
  }
  sqliteFree(p->apHash);
  memset(p, 0, sizeof(*p));
}

/*
** Add the given AggElem to the hash array
*/
static void AggEnhash(Agg *p, AggElem *pElem){
  int h = sqliteHashNoCase(pElem->zKey, 0) % p->nHash;
  pElem->pHash = p->apHash[h];
  p->apHash[h] = pElem;
}

/*
** Change the size of the hash array to the amount given.
*/
static void AggRehash(Agg *p, int nHash){
  int size;
  AggElem *pElem;
  if( p->nHash==nHash ) return;
  size = nHash * sizeof(AggElem*);
  p->apHash = sqliteRealloc(p->apHash, size );

  }
  return 0;
}

/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, list, and/or
** sorters that were left open.
*/
static void Cleanup(Vdbe *p){
  int i;
  PopStack(p, p->tos+1);
  sqliteFree(p->azColName);
  p->azColName = 0;
  for(i=0; i<p->nCursor; i++){
    if( p->aCsr[i].pCursor ){
      sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
      p->aCsr[i].pCursor = 0;
    }
  }
  sqliteFree(p->aCsr);
  p->aCsr = 0;
  p->nCursor = 0;
  for(i=0; i<p->nMem; i++){
    if( p->aMem[i].s.flags & STK_Dyn ){
      sqliteFree(p->aMem[i].z);
    }
  }
  sqliteFree(p->aMem);
  p->aMem = 0;

int sqliteVdbeList(
  Vdbe *p,                   /* The VDBE */
  sqlite_callback xCallback, /* The callback */
  void *pArg,                /* 1st argument to callback */
  char **pzErrMsg            /* Error msg written here */
){
  int i, rc;
  char *azValue[6];
  char zAddr[20];
  char zP1[20];
  char zP2[20];
  static char *azColumnNames[] = {
     "addr", "opcode", "p1", "p2", "p3", 0
  };

  if( xCallback==0 ) return 0;
  azValue[0] = zAddr;
  azValue[2] = zP1;
  azValue[3] = zP2;
  azValue[5] = 0;
  rc = SQLITE_OK;
  /* if( pzErrMsg ){ *pzErrMsg = 0; } */
  for(i=0; rc==SQLITE_OK && i<p->nOp; i++){
    sprintf(zAddr,"%d",i);
    sprintf(zP1,"%d", p->aOp[i].p1);
    sprintf(zP2,"%d", p->aOp[i].p2);
    azValue[4] = p->aOp[i].p3;
    azValue[1] = zOpName[p->aOp[i].opcode];
    if( xCallback(pArg, 5, azValue, azColumnNames) ){
      rc = SQLITE_ABORT;
    }
  }
  return rc;
}

/*

          p->aStack[tos].flags = STK_Real;
        }
        break;
      }

      /* Opcode: Not * * *
      **
      ** Interpret the top of the stack as a boolean value.  Replace it
      ** with its complement.
      */
      case OP_Not: {
        int tos = p->tos;
        if( p->tos<0 ) goto not_enough_stack;
        Integerify(p, tos);
        Release(p, tos);

        p->aStack[p->tos].flags = STK_Str|STK_Dyn;
        p->zStack[p->tos] = zNewKey;
        break;
      }

      /* Opcode: Open P1 P2 P3
      **
      ** Open a new cursor for the database file named P3.  Give the
      ** cursor an identifier P1.  The P1 values need not be






      ** contiguous but all P1 values should be small integers.  It is
      ** an error for P1 to be negative.
      **
      ** Open readonly if P2==0 and for reading and writing if P2!=0.
      ** The file is created if it does not already exist and P2!=0.
      ** If there is already another cursor opened with identifier P1,
      ** then the old cursor is closed first.  All cursors are
      ** automatically closed when the VDBE finishes execution.
      **
      ** If P3 is null or an empty string, a temporary database file
      ** is created.  This temporary database file is automatically 
      ** deleted when the cursor is closed.
      */
      case OP_Open: {
        int i = pOp->p1;
        if( i<0 ) goto bad_instruction;
        if( i>=p->nCursor ){
          int j;
          p->aCsr = sqliteRealloc( p->aCsr, (i+1)*sizeof(Cursor) );
          if( p->aCsr==0 ){ p->nCursor = 0; goto no_mem; }
          for(j=p->nCursor; j<=i; j++) p->aCsr[j].pCursor = 0;
          p->nCursor = i+1;
        }else if( p->aCsr[i].pCursor ){
          sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
        }
        rc = sqliteDbbeOpenCursor(p->pBe, pOp->p3, pOp->p2,&p->aCsr[i].pCursor);
        switch( rc ){
          case SQLITE_BUSY: {
            sqliteSetString(pzErrMsg,"table ", pOp->p3, " is locked", 0);
            break;
          }
          case SQLITE_PERM: {
            sqliteSetString(pzErrMsg, pOp->p2 ? "write" : "read",
              " permission denied for table ", pOp->p3, 0);
            break;
          }
          case SQLITE_READONLY: {
            sqliteSetString(pzErrMsg,"table ", pOp->p3, 
               " is readonly", 0);
            break;
          }
          case SQLITE_NOMEM: {
            goto no_mem;
          }
        }
        p->aCsr[i].index = 0;
        p->aCsr[i].keyAsData = 0;
        break;
      }

      /* Opcode: Close P1 * *
      **
      ** Close a cursor previously opened as P1.  If P1 is not
      ** currently open, this instruction is a no-op.
      */
      case OP_Close: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          sqliteDbbeCloseCursor(p->aCsr[i].pCursor);
          p->aCsr[i].pCursor = 0;
        }
        break;
      }

      /* Opcode: Fetch P1 * *
      **
      ** Pop the top of the stack and use its value as a key to fetch
      ** a record from cursor P1.  The key/data pair is held
      ** in the P1 cursor until needed.

      */
      case OP_Fetch: {
        int i = pOp->p1;
        int tos = p->tos;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            sqliteDbbeFetch(p->aCsr[i].pCursor, sizeof(int), 
                           (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            sqliteDbbeFetch(p->aCsr[i].pCursor, p->aStack[tos].n, 
                           p->zStack[tos]);
          }
          p->nFetch++;
        }
        PopStack(p, 1);
        break;
      }

        p->aStack[i].flags = STK_Int;
        break;
      }

      /* Opcode: Distinct P1 P2 *
      **
      ** Use the top of the stack as a key.  If a record with that key
      ** does not exist in file P1, then jump to P2.  If the record
      ** does already exist, then fall thru.  The record is not retrieved.
      ** The key is not popped from the stack.
      **
      ** This operation is similar to NotFound except that this operation
      ** does not pop the key from the stack.
      */
      /* Opcode: Found P1 P2 *
      **
      ** Use the top of the stack as a key.  If a record with that key
      ** does exist in file P1, then jump to P2.  If the record
      ** does not exist, then fall thru.  The record is not retrieved.
      ** The key is popped from the stack.
      */
      /* Opcode: NotFound P1 P2 *
      **
      ** Use the top of the stack as a key.  If a record with that key
      ** does not exist in file P1, then jump to P2.  If the record
      ** does exist, then fall thru.  The record is not retrieved.
      ** The key is popped from the stack.
      **
      ** The difference between this operation and Distinct is that
      ** Distinct does not pop the key from the stack.
      */
      case OP_Distinct:
      case OP_NotFound:
      case OP_Found: {
        int i = pOp->p1;
        int tos = p->tos;
        int alreadyExists = 0;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor ){
          if( p->aStack[tos].flags & STK_Int ){
            alreadyExists = sqliteDbbeTest(p->aCsr[i].pCursor, sizeof(int), 
                                          (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            alreadyExists = sqliteDbbeTest(p->aCsr[i].pCursor,p->aStack[tos].n, 
                                           p->zStack[tos]);
          }
        }
        if( pOp->opcode==OP_Found ){
          if( alreadyExists ) pc = pOp->p2 - 1;
        }else{
          if( !alreadyExists ) pc = pOp->p2 - 1;
        }
        if( pOp->opcode!=OP_Distinct ){
          PopStack(p, 1);
        }
        break;
      }

      /* Opcode: New P1 * *
      **
      ** Get a new integer key not previous used by the database file
      ** associated with cursor P1 and push it onto the stack.
      */
      case OP_New: {
        int i = pOp->p1;
        int v;
        if( i<0 || i>=p->nCursor || p->aCsr[i].pCursor==0 ){
          v = 0;
        }else{
          v = sqliteDbbeNew(p->aCsr[i].pCursor);
        }
        NeedStack(p, p->tos+1);
        p->tos++;
        p->aStack[p->tos].i = v;
        p->aStack[p->tos].flags = STK_Int;
        break;
      }

      /* Opcode: Put P1 * *
      **
      ** Write an entry into the database file P1.  A new entry is
      ** created if it doesn't already exist, or the data for an existing
      ** entry is overwritten.  The data is the value on the top of the
      ** stack.  The key is the next value down on the stack.  The stack
      ** is popped twice by this instruction.
      */
      case OP_Put: {
        int tos = p->tos;
        int nos = p->tos-1;
        int i = pOp->p1;
        if( nos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          char *zKey;
          int nKey;
          if( (p->aStack[nos].flags & STK_Int)==0 ){
            if( Stringify(p, nos) ) goto no_mem;
            nKey = p->aStack[nos].n;
            zKey = p->zStack[nos];
          }else{
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[nos].i;
          }
          sqliteDbbePut(p->aCsr[i].pCursor, nKey, zKey,
                        p->aStack[tos].n, p->zStack[tos]);
        }
        PopStack(p, 2);
        break;
      }

      /* Opcode: Delete P1 * *
      **
      ** The top of the stack is a key.  Remove this key and its data
      ** from database file P1.  Then pop the stack to discard the key.
      */
      case OP_Delete: {
        int tos = p->tos;
        int i = pOp->p1;
        if( tos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          char *zKey;
          int nKey;
          if( p->aStack[tos].flags & STK_Int ){
            nKey = sizeof(int);
            zKey = (char*)&p->aStack[tos].i;
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            nKey = p->aStack[tos].n;
            zKey = p->zStack[tos];
          }
          sqliteDbbeDelete(p->aCsr[i].pCursor, 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
      ** processing compound selects.
      */
      case OP_KeyAsData: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          p->aCsr[i].keyAsData = pOp->p2;
        }
        break;
      }

      /* Opcode: Field P1 P2 *
      **
      ** Interpret the data in the most recent fetch from cursor P1
      ** is a structure built using the MakeRecord instruction.
      ** Push onto the stack the value of the P2-th field of that
      ** structure.
      ** 
      ** The value pushed is just a pointer to the data in the cursor.
      ** The value will go away the next time a record is fetched from P1,
      ** or when P1 is closed.  Make a copy of the string (using
      ** "Concat 1 0 0") if it needs to persist longer than that.
      **
      ** If the KeyAsData opcode has previously executed on this cursor,
      ** then the field might be extracted from the key rather than the
      ** data.
      **
      ** Viewed from a higher level, this instruction retrieves the
      ** data from a single column in a particular row of an SQL table
      ** file.  Perhaps the name of this instruction should be
      ** "Column" instead of "Field"...
      */
      case OP_Field: {
        int *pAddr;
        int amt;
        int i = pOp->p1;
        int p2 = pOp->p2;
        int tos = ++p->tos;
        DbbeCursor *pCrsr;
        char *z;

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

      /* Opcode: Key P1 * *
      **
      ** Push onto the stack an integer which is the first 4 bytes of the
      ** the key to the current entry in a sequential scan of the database
      ** file P1.  The sequential scan should have been started using the 
      ** Next opcode.
      */
      case OP_Key: {
        int i = pOp->p1;
        int tos = ++p->tos;
        DbbeCursor *pCrsr;

        if( NeedStack(p, p->tos) ) goto no_mem;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          char *z = sqliteDbbeReadKey(pCrsr, 0);
          if( p->aCsr[i].keyAsData ){
            p->zStack[tos] = z;
            p->aStack[tos].flags = STK_Str;
            p->aStack[tos].n = sqliteDbbeKeyLength(pCrsr);
          }else{
            memcpy(&p->aStack[tos].i, z, sizeof(int));
            p->aStack[tos].flags = STK_Int;
          }
        }
        break;
      }

      /* Opcode: Rewind P1 * *
      **
      ** The next use of the Key or Field or Next instruction for P1 
      ** will refer to the first entry in the database file.
      */
      case OP_Rewind: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          sqliteDbbeRewind(p->aCsr[i].pCursor);
        }
        break;
      }

      /* Opcode: Next P1 P2 *
      **
      ** Advance P1 to the next key/data pair in the file.  Or, if there are no
      ** more key/data pairs, rewind P1 and jump to location P2.
      */
      case OP_Next: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor && p->aCsr[i].pCursor!=0 ){
          if( sqliteDbbeNextKey(p->aCsr[i].pCursor)==0 ){
            pc = pOp->p2 - 1;
          }else{
            p->nFetch++;
          }
        }
        break;
      }

      /* Opcode: ResetIdx P1 * *
      **
      ** Begin treating the current data in cursor P1 as a bunch of integer
      ** keys to records of a (separate) SQL table file.  This instruction
      ** causes the new NextIdx instruction push the first integer table
      ** key in the data.
      */
      case OP_ResetIdx: {
        int i = pOp->p1;
        if( i>=0 && i<p->nCursor ){
          p->aCsr[i].index = 0;
        }
        break;
      }

      /* Opcode: NextIdx P1 P2 *
      **
      ** The P1 cursor points to an SQL index.  The data from the most
      ** recent fetch on that cursor consists of a bunch of integers where
      ** each integer is the key to a record in an SQL table file.
      ** This instruction grabs the next integer table key from the data
      ** of P1 and pushes that integer onto the stack.  The first time
      ** this instruction is executed after a fetch, the first integer 
      ** table key is pushed.  Subsequent integer table keys are pushed 
      ** in each subsequent execution of this instruction.
      **
      ** If there are no more integer table keys in the data of P1
      ** when this instruction is executed, then nothing gets pushed and
      ** there is an immediate jump to instruction P2.
      */
      case OP_NextIdx: {
        int i = pOp->p1;
        int tos = ++p->tos;
        DbbeCursor *pCrsr;

        if( NeedStack(p, p->tos) ) goto no_mem;
        p->zStack[tos] = 0;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int *aIdx;
          int nIdx;
          int j;
          nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
          aIdx = (int*)sqliteDbbeReadData(pCrsr, 0);
          for(j=p->aCsr[i].index; j<nIdx; j++){
            if( aIdx[j]!=0 ){
              p->aStack[tos].i = aIdx[j];
              p->aStack[tos].flags = STK_Int;
              break;
            }
          }
          if( j>=nIdx ){
            j = -1;
            pc = pOp->p2 - 1;
            PopStack(p, 1);
          }
          p->aCsr[i].index = j+1;
        }
        break;
      }

      /* Opcode: PutIdx P1 * *
      **
      ** The top of the stack hold an SQL index key (probably made using the
      ** MakeKey instruction) and next on stack holds an integer which
      ** the key to an SQL table entry.  Locate the record in cursor P1
      ** that has the same key as on the TOS.  Create a new record if
      ** necessary.  Then append the integer table key to the data for that
      ** record and write it back to the P1 file.

      */
      case OP_PutIdx: {
        int i = pOp->p1;
        int tos = p->tos;
        int nos = tos - 1;
        DbbeCursor *pCrsr;
        if( nos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int r;
          int newVal;
          Integerify(p, nos);
          newVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = sqliteDbbeFetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ){
            /* Create a new record for this index */
            sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                          sizeof(int), (char*)&newVal);
          }else{
            /* Extend the existing record */
            int nIdx;
            int *aIdx;
            nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
            aIdx = sqliteMalloc( sizeof(int)*(nIdx+1) );
            if( aIdx==0 ) goto no_mem;
            sqliteDbbeCopyData(pCrsr, 0, nIdx*sizeof(int), (char*)aIdx);
            aIdx[nIdx] = newVal;
            sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos],
                          sizeof(int)*(nIdx+1), (char*)aIdx);
            sqliteFree(aIdx);
          }
        }
        PopStack(p, 2);
        break;
      }

      /* Opcode: DeleteIdx P1 * *
      **
      ** The top of the stack is a key and next on stack is integer
      ** which is the key to a record in an SQL table.
      ** Locate the record in the cursor P1 (P1 represents an SQL index)
      ** that has the same key as the top of stack.  Then look through
      ** the integer table-keys contained in the data of the P1 record.
      ** Remove the integer table-key that matches the NOS and write the
      ** revised data back to P1 with the same key.
      **
      ** If this routine removes the very last integer table-key from
      ** the P1 data, then the corresponding P1 record is deleted.

      */
      case OP_DeleteIdx: {
        int i = pOp->p1;
        int tos = p->tos;
        int nos = tos - 1;
        DbbeCursor *pCrsr;
        if( nos<0 ) goto not_enough_stack;
        if( i>=0 && i<p->nCursor && (pCrsr = p->aCsr[i].pCursor)!=0 ){
          int *aIdx;
          int nIdx;
          int j;
          int r;
          int oldVal;
          Integerify(p, nos);
          oldVal = p->aStack[nos].i;
          if( Stringify(p, tos) ) goto no_mem;
          r = sqliteDbbeFetch(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          if( r==0 ) break;
          nIdx = sqliteDbbeDataLength(pCrsr)/sizeof(int);
          aIdx = (int*)sqliteDbbeReadData(pCrsr, 0);
          for(j=0; j<nIdx && aIdx[j]!=oldVal; j++){}
          if( j>=nIdx ) break;
          aIdx[j] = aIdx[nIdx-1];
          if( nIdx==1 ){
            sqliteDbbeDelete(pCrsr, p->aStack[tos].n, p->zStack[tos]);
          }else{
            sqliteDbbePut(pCrsr, p->aStack[tos].n, p->zStack[tos], 
                          sizeof(int)*(nIdx-1), (char*)aIdx);
          }
        }
        PopStack(p, 2);
        break;
      }

      /* Opcode: Destroy * * P3
      **
      ** Drop the disk file whose name is P3.  All key/data pairs in
      ** the file are deleted and the file itself is removed
      ** from the disk.
      */
      case OP_Destroy: {
        sqliteDbbeDropTable(p->pBe, pOp->p3);
        break;
      }

      /* Opcode: Reorganize * * P3
      **
      ** Compress, optimize, and tidy up the GDBM file named by P3.
      */
      case OP_Reorganize: {
        sqliteDbbeReorganizeTable(p->pBe, pOp->p3);
        break;
      }

      /* Opcode: ListOpen P1 * *
      **
      ** Open a file used for temporary storage of integer table keys.  P1
      ** will server as a handle to this temporary file for future
      ** interactions.  If another temporary file with the P1 handle is
      ** already opened, the prior file is closed and a new one opened
      ** in its place.
      */
      case OP_ListOpen: {
        int i = pOp->p1;

        }
        break;
      }

      /* Opcode: ListRead P1 P2 *
      **
      ** Attempt to read an integer from temporary storage buffer P1
      ** and push it onto the stack.  If the storage buffer is empty, 
      ** push nothing but instead jump to P2.
      */
      case OP_ListRead: {
        int i = pOp->p1;
        int val, amt;
        if( i<0 || i>=p->nList || p->apList[i]==0 ) goto bad_instruction;
        amt = fread(&val, sizeof(int), 1, p->apList[i]);

        pc = pOp->p2 - 1;
        break;
      }

      /* Opcode: FileField P1 * *
      **
      ** Push onto the stack the P1-th field of the most recently read line
      ** from the input file.
      */
      case OP_FileField: {
        int i = pOp->p1;
        char *z;
        if( NeedStack(p, p->tos+1) ) goto no_mem;
        if( i>=0 && i<p->nField && p->azField ){
          z = p->azField[i];

        }
        PopStack(p, 1);
        break; 
      }

      /* Opcode: AggIncr P1 P2 *
      **
      ** Increase the integer value in the P2-th field of the aggregate
      ** element current in focus by an amount P1.
      */
      case OP_AggIncr: {
        AggElem *pFocus = AggInFocus(p->agg);
        int i = pOp->p2;
        if( pFocus==0 ) goto no_mem;
        if( i>=0 && i<p->agg.nMem ){
          Mem *pMem = &pFocus->aMem[i];

**   http://www.hwaci.com/drh/
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.8 2000/06/21 13:59:13 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.
*/
typedef struct ExprInfo ExprInfo;
struct ExprInfo {
  Expr *p;                /* Pointer to the subexpression */
  int indexable;          /* True if this subexprssion is usable by an index */
  int idxLeft;            /* p->pLeft is a column in this table number. -1 if
                          ** p->pLeft is not the column of any table */
  int idxRight;           /* p->pRight is a column in this table number. -1 if
                          ** p->pRight is not the column of any table */
  unsigned prereqLeft;    /* Tables referenced by p->pLeft */
  unsigned prereqRight;   /* Tables referenced by p->pRight */
};

/*
** Determine the number of elements in an array.
*/

** "base" is the cursor number (the value of the iTable field) that
** corresponds to the first entry in the table list.  This is the
** same as pParse->nTab.
*/
static int exprTableUsage(int base, Expr *p){
  unsigned int mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
    return 1<< (p->iTable - base);
  }
  if( p->pRight ){
    mask = exprTableUsage(base, p->pRight);
  }
  if( p->pLeft ){
    mask |= exprTableUsage(base, p->pLeft);

  Expr *pExpr = pInfo->p;
  pInfo->prereqLeft = exprTableUsage(base, pExpr->pLeft);
  pInfo->prereqRight = exprTableUsage(base, pExpr->pRight);
  pInfo->indexable = 0;
  pInfo->idxLeft = -1;
  pInfo->idxRight = -1;
  if( pExpr->op==TK_EQ && (pInfo->prereqRight & pInfo->prereqLeft)==0 ){
    if( pExpr->pRight->op==TK_COLUMN ){
      pInfo->idxRight = pExpr->pRight->iTable - base;
      pInfo->indexable = 1;
    }
    if( pExpr->pLeft->op==TK_COLUMN ){
      pInfo->idxLeft = pExpr->pLeft->iTable - base;
      pInfo->indexable = 1;
    }
  }
}

/*

    Index *pIdx;
    Index *pBestIdx = 0;

    /* Do a search for usable indices.  Leave pBestIdx pointing to
    ** the most specific usable index.
    **
    ** "Most specific" means that pBestIdx is the usable index that
    ** has the largest value for nColumn.  A usable index is one for
    ** which there are subexpressions to compute every column of the
    ** index.
    */
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      int j;
      int columnMask = 0;

      if( pIdx->nColumn>32 ) continue;
      for(j=0; j<nExpr; j++){
        if( aExpr[j].idxLeft==idx 
             && (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
          int iColumn = aExpr[j].p->pLeft->iColumn;
          int k;
          for(k=0; k<pIdx->nColumn; k++){
            if( pIdx->aiColumn[k]==iColumn ){
              columnMask |= 1<<k;
              break;
            }
          }
        }
        if( aExpr[j].idxRight==idx 
             && (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
          int iColumn = aExpr[j].p->pRight->iColumn;
          int k;
          for(k=0; k<pIdx->nColumn; k++){
            if( pIdx->aiColumn[k]==iColumn ){
              columnMask |= 1<<k;
              break;
            }
          }
        }
      }
      if( columnMask + 1 == (1<<pIdx->nColumn) ){
        if( pBestIdx==0 || pBestIdx->nColumn<pIdx->nColumn ){
          pBestIdx = pIdx;
        }
      }
    }
    aIdx[i] = pBestIdx;
    loopMask |= 1<<idx;
  }

      ** scan of the table.
      */
      sqliteVdbeAddOp(v, OP_Next, base+idx, brk, 0, cont);
      haveKey = 0;
    }else{
      /* Case 2:  We do have a usable index in pIdx.
      */
      for(j=0; j<pIdx->nColumn; j++){
        for(k=0; k<nExpr; k++){
          if( aExpr[k].p==0 ) continue;
          if( aExpr[k].idxLeft==idx 
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && aExpr[k].p->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pRight);
            aExpr[k].p = 0;
            break;
          }
          if( aExpr[k].idxRight==idx 
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqliteExprCode(pParse, aExpr[k].p->pLeft);
            aExpr[k].p = 0;
            break;
          }
        }
      }
      sqliteVdbeAddOp(v, OP_MakeKey, pIdx->nColumn, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_Fetch, base+pTabList->nId+i, 0, 0, 0);
      sqliteVdbeAddOp(v, OP_NextIdx, base+pTabList->nId+i, brk, 0, cont);
      if( i==pTabList->nId-1 && pushKey ){
        haveKey = 1;
      }else{
        sqliteVdbeAddOp(v, OP_Fetch, idx, 0, 0, 0);
        haveKey = 0;

#   drh@hwaci.com
#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the DELETE FROM statement.
#
# $Id: delete.test,v 1.6 2000/06/21 13:59:13 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Try to delete from a non-existant table.
#
do_test delete-1.1 {

# Semantic errors in the WHERE clause
#
do_test delete-4.1 {
  execsql {CREATE TABLE table2(f1 int, f2 int)}
  set v [catch {execsql {DELETE FROM table2 WHERE f3=5}} msg]
  lappend v $msg
} {1 {no such column: f3}}

do_test delete-4.2 {
  set v [catch {execsql {DELETE FROM table2 WHERE xyzzy(f1+4)}} msg]
  lappend v $msg
} {1 {no such function: xyzzy}}

finish_test

#   drh@hwaci.com
#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the IN and BETWEEN operator.
#
# $Id: in.test,v 1.3 2000/06/21 13:59:13 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Generate the test data we will need for the first squences of tests.
#
do_test in-1.0 {

do_test in-2.10 {
  set v [catch {execsql {SELECT a FROM t1 WHERE min(0,b IN (a,30))}} msg]
  lappend v $msg
} {1 {right-hand side of IN operator must be constant}}
do_test in-2.11 {
  set v [catch {execsql {SELECT a FROM t1 WHERE c IN (10,20)}} msg]
  lappend v $msg
} {1 {no such column: c}}

# Testing the IN operator where the right-hand side is a SELECT
#
do_test in-3.1 {
  execsql {
    SELECT a FROM t1
    WHERE b IN (SELECT b FROM t1 WHERE a<5)

#   drh@hwaci.com
#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: select1.test,v 1.6 2000/06/21 13:59:13 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Try to select on a non-existant table.
#
do_test select1-1.1 {

  set v [catch {execsql {SELECT * FROM test2, test1}} msg]
  lappend v $msg
} {1 {no such table: test2}}

execsql {INSERT INTO test1(f1,f2) VALUES(11,22)}


# Make sure the columns are extracted correctly.
#
do_test select1-1.4 {
  execsql {SELECT f1 FROM test1}
} {11}
do_test select1-1.5 {
  execsql {SELECT f2 FROM test1}
} {22}

  set v [catch {execsql {SELECT max(f1) FROM test1 ORDER BY f2}} msg]
  lappend v $msg
} {0 33}

execsql {CREATE TABLE test2(t1 test, t2 text)}
execsql {INSERT INTO test2 VALUES('abc','xyz')}

# Check for column naming
#
do_test select1-6.1 {
  set v [catch {execsql2 {SELECT f1 FROM test1 ORDER BY f2}} msg]
  lappend v $msg
} {0 {f1 11 f1 33}}
do_test select1-6.2 {
  set v [catch {execsql2 {SELECT f1 as xyzzy FROM test1 ORDER BY f2}} msg]

         ORDER BY f2}} msg]
  lappend v $msg
} {0 {A.f1 11 test2.t1 abc A.f1 33 test2.t1 abc}}
do_test select1-6.8 {
  set v [catch {execsql2 {SELECT A.f1, f1 FROM test1 as A, test1 as B 
         ORDER BY f2}} msg]
  lappend v $msg
} {1 {ambiguous column name: f1}}
do_test select1-6.8b {
  set v [catch {execsql2 {SELECT A.f1, B.f1 FROM test1 as A, test1 as B 
         ORDER BY f2}} msg]
  lappend v $msg
} {1 {ambiguous column name: f2}}
do_test select1-6.8c {
  set v [catch {execsql2 {SELECT A.f1, f1 FROM test1 as A, test1 as A 
         ORDER BY f2}} msg]
  lappend v $msg
} {1 {ambiguous column name: A.f1}}
do_test select1-6.9 {
  set v [catch {execsql2 {SELECT A.f1, B.f1 FROM test1 as A, test1 as B 
         ORDER BY A.f1, B.f1}} msg]
  lappend v $msg
} {0 {A.f1 11 B.f1 11 A.f1 11 B.f1 33 A.f1 33 B.f1 11 A.f1 33 B.f1 33}}

finish_test

#   drh@hwaci.com
#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: select2.test,v 1.7 2000/06/21 13:59:13 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Create a table with some data
#
execsql {CREATE TABLE tbl1(f1 int, f2 int)}

} {500}
do_test select2-3.2c {
  execsql {SELECT f1 FROM tbl2 WHERE f2=1000}
} {500}
do_test select2-3.2d {
  set t1 [lindex [time {execsql {SELECT f1 FROM tbl2 WHERE 1000=f2}} 1] 0]
  set t2 [lindex [time {execsql {SELECT f1 FROM tbl2 WHERE f2=1000}} 1] 0]
  expr {$t1*0.8<$t2 && $t2*0.8<$t1}
} {1}

# Make sure queries run faster with an index than without
#
do_test select2-3.3 {
  set t1 [lindex [time {execsql {SELECT f1 from tbl2 WHERE f2==2000}} 1] 0]
  execsql {DROP INDEX idx1}
  set t2 [lindex [time {execsql {SELECT f1 FROM tbl2 WHERE f2==2000}} 1] 0]
  expr {$t1*25 < $t2}
} {1}

finish_test

#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing aggregate functions and the
# GROUP BY and HAVING clauses of SELECT statements.
#
# $Id: select5.test,v 1.4 2000/06/21 13:59:13 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Build some test data
#
set fd [open data1.txt w]

# Some error messages associated with aggregates and GROUP BY
#
do_test select5-2.1 {
  set v [catch {execsql {
    SELECT y, count(*) FROM t1 GROUP BY z ORDER BY y
  }} msg]
  lappend v $msg
} {1 {no such column: z}}
do_test select5-2.2 {
  set v [catch {execsql {
    SELECT y, count(*) FROM t1 GROUP BY z(y) ORDER BY y
  }} msg]
  lappend v $msg
} {1 {no such function: z}}
do_test select5-2.3 {

  lappend v $msg
} {1 {no such function: z}}
do_test select5-2.5 {
  set v [catch {execsql {
    SELECT y, count(*) FROM t1 GROUP BY y HAVING count(*)<z ORDER BY y
  }} msg]
  lappend v $msg
} {1 {no such column: z}}

# Get the Agg function to rehash in vdbe.c
#
do_test select5-3.1 {
  execsql {
    SELECT x, count(*), avg(y) FROM t1 GROUP BY x HAVING x<4 ORDER BY x
  }

#   drh@hwaci.com
#   http://www.hwaci.com/drh/
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the UPDATE statement.
#
# $Id: update.test,v 1.4 2000/06/21 13:59:14 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Try to update an non-existent table
#
do_test update-1.1 {

  for {set i 1} {$i<=10} {incr i} {
    set sql "INSERT INTO test1 VALUES($i,[expr {int(pow(2,$i))}])"
    execsql $sql
  }
  execsql {SELECT * FROM test1 ORDER BY f1}
} {1 2 2 4 3 8 4 16 5 32 6 64 7 128 8 256 9 512 10 1024}

# Unknown column name in an expression
#
do_test update-3.2 {
  set v [catch {execsql {UPDATE test1 SET f1=f3*2 WHERE f2==32}} msg]
  lappend v $msg
} {1 {no such column: f3}}
do_test update-3.3 {
  set v [catch {execsql {UPDATE test1 SET f1=test2.f1*2 WHERE f2==32}} msg]
  lappend v $msg
} {1 {no such column: test2.f1}}
do_test update-3.4 {
  set v [catch {execsql {UPDATE test1 SET f3=f1*2 WHERE f2==32}} msg]
  lappend v $msg
} {1 {no such column: f3}}

# Actually do some updates
#
do_test update-3.5 {
  execsql {UPDATE test1 SET f2=f2*3}
  execsql {SELECT * FROM test1 ORDER BY f1}
} {1 6 2 12 3 24 4 48 5 96 6 192 7 384 8 768 9 1536 10 3072}

# Error messages
#
do_test update-4.1 {
  set v [catch {execsql {
    UPDATE test1 SET x=11 WHERE f1=1025
  }} msg]
  lappend v $msg
} {1 {no such column: x}}
do_test update-4.2 {
  set v [catch {execsql {
    UPDATE test1 SET f1=x(11) WHERE f1=1025
  }} msg]
  lappend v $msg
} {1 {no such function: x}}
do_test update-4.3 {
  set v [catch {execsql {
    UPDATE test1 SET f1=11 WHERE x=1025
  }} msg]
  lappend v $msg
} {1 {no such column: x}}
do_test update-4.4 {
  set v [catch {execsql {
    UPDATE test1 SET f1=11 WHERE x(f1)=1025
  }} msg]
  lappend v $msg
} {1 {no such function: x}}






finish_test

#
# Run this Tcl script to generate the sqlite.html file.
#
set rcsid {$Id: c_interface.tcl,v 1.5 2000/06/21 13:59:14 drh Exp $}

puts {<html>
<head>
  <title>The C language interface to the SQLite library</title>
</head>
<body bgcolor=white>
<h1 align=center>

pointer to an opaque <b>sqlite</b> structure.  This pointer will
be the first argument to all subsequent SQLite function calls that
deal with the same database.  NULL is returned if the open fails
for any reason.</p>

<h2>Closing the database</h2>

<p>To close an SQLite database, call the <b>sqlite_close()</b>
function passing it the sqlite structure pointer that was obtained
from a prior call to <b>sqlite_open</b>.

<h2>Executing SQL statements</h2>

<p>The <b>sqlite_exec()</b> function is used to process SQL statements
and queries.  This function requires 5 parameters as follows:</p>

argv[i] == 0
</pre></blockquote>
<p>The names of the columns are contained in the fourth argument.</p>

<p>The callback function should normally return 0.  If the callback
function returns non-zero, the query is immediately aborted and 
<b>sqlite_exec()</b> will return SQLITE_ABORT.</p>

<p>The <b>sqlite_exec()</b> function returns an integer to indicate
success or failure of the operation.  The following are possible
return values:</p>

<blockquote>
<dl>
<dt>SQLITE_OK</dt>
<dd><p>This value is returned if everything worked and there were no errors.
</p></dd>
<dt>SQLITE_INTERNAL</dt>
<dd><p>This value indicates that an internal consistency check within
the SQLite library failed.  This can only happen if there is a bug in
the SQLite library.  If you ever get an SQLITE_INTERNAL reply from
an <b>sqlite_exec()</b> call, please report the problem on the SQLite
mailing list.
</p></dd>
<dt>SQLITE_ERROR</dt>
<dd><p>This return value indicates that there was an error in the SQL
that was passed into the <b>sqlite_exec()</b>.
</p></dd>
<dt>SQLITE_PERM</dt>
<dd><p>This return value says that the access permissions on one of the
GDBM files is such that the file cannot be opened.
</p></dd>
<dt>SQLITE_ABORT</dt>
<dd><p>This value is returned if the callback function returns non-zero.
</p></dd>
<dt>SQLITE_BUSY</dt>
<dd><p>This return code indicates that one of the underlying GDBM files
is locked because it is currently being accessed by another thread or
process.  GDBM allows mutiple readers of the same file, but only one
writer.  So multiple processes can query an SQLite database at once.
But only a single process can write to an SQLite database at one time.
If an attempt is made to write to an SQLite database that another
process is currently reading, the write is not performed and 
<b>sqlite_exec()</b> returns SQLITE_BUSY.  Similarly, an attempt to read
an SQLite database that is currently being written by another process
will return SQLITE_BUSY.  In both cases, the write or query attempt
can be retried after the other process finishes.</p>
<p>Note that locking is done at the file level.  One process can
write to table ABC (for example) while another process simultaneously
reads from a different table XYZ.  But you cannot have two processes reading
and writing table ABC at the same time.
</p></dd>
<dt>SQLITE_NOMEM</dt>
<dd><p>This value is returned if a call to <b>malloc()</b> fails.
</p></dd>
<dt>SQLITE_READONLY</dt>
<dd><p>This return code indicates that an attempt was made to write to
a database file that was originally opened for reading only.  This can
happen if the callback from a query attempts to update the table
being queried.
</p></dd>
</dl>
</blockquote>

<h2>Testing for a complete SQL statement</h2>

<p>The last interface routine to SQLite is a convenience function used
to test whether or not a string forms a complete SQL statement.
If the <b>sqlite_complete()</b> function returns true when its input
is a string, then the argument forms a complete SQL statement.

#
# Run this Tcl script to generate the sqlite.html file.
#
set rcsid {$Id: sqlite.tcl,v 1.9 2000/06/21 13:59:14 drh Exp $}

puts {<html>
<head>
  <title>sqlite: A program of interacting with SQLite databases</title>
</head>
<body bgcolor=white>
<h1 align=center>

.dump                  Dump database in a text format
.exit                  Exit this program
.explain               Set output mode suitable for EXPLAIN
.header ON|OFF         Turn display of headers on or off
.help                  Show this message
.indices TABLE         Show names of all indices on TABLE
.mode MODE             Set mode to one of "line", "column", "list", or "html"
.mode insert TABLE     Generate SQL insert statements for TABLE
.output FILENAME       Send output to FILENAME
.output stdout         Send output to the screen
.schema ?TABLE?        Show the CREATE statements
.separator STRING      Change separator string for "list" mode
.tables                List names all tables in the database
.width NUM NUM ...     Set column widths for "column" mode
sqlite> 
}

puts {
<h2>Changing Output Formats</h2>

<p>The sqlite program is able to show the results of a query
in five different formats: "line", "column", "list", "html", and "insert".
You can use the ".mode" dot command to switch between these three output
formats.</p>

<p>The default output mode is "list".  In
list mode, each record of a query result is written on one line of
output and each column within that record is separated by a specific
separator string.  The default separator is a pipe symbol ("|").
List mode is especially useful when you are going to send the output
of a query to another program (such as AWK) for additional processing.</p>}

Code {
sqlite> (((.mode list)))
sqlite> (((select * from tbl1;)))

sqlite> (((select * from tbl1;)))
hello, 10
goodbye, 20
sqlite>
}

puts {
<p>In "line" mode, each column in a row of the database
is shown on a line by itself.  Each line consists of the column
name, an equal sign and the column data.  Successive records are
separated by a blank line.  Here is an example of line mode
output:</p>}

Code {
sqlite> (((.mode line)))
sqlite> (((select * from tbl1;)))
one = hello

sqlite> (((select * from tbl1;)))
hello         10    
goodbye       20    
sqlite>
}

puts {
<p>Another useful output mode is "insert".  In insert mode, the output
is formatted to look like SQL INSERT statements.  You can use insert
mode to generate text that can later be used to input data into a 
different database.</p>

<p>The last output mode is "html".  In this mode, sqlite writes
the results of the query as an XHTML table.  The beginning
&lt;TABLE&gt; and the ending &lt;/TABLE&gt; are not written, but
all of the intervening &lt;TR&gt;s, &lt;TH&gt;s, and &lt;TD&gt;s
are.  The html output mode is envisioned as being useful for
CGI.</p>
}