if( rc==SQLITE4_OK ){
          rc = sqlite4KVCursorData(pCsr->pCsr, 0, -1, &aData, &nData);
        }

        if( rc==SQLITE4_OK ){
          int i;
          ValueDecoder *pCodec;   /* The decoder object */

          rc = sqlite4VdbeCreateDecoder(db, aData, nData, pInfo->nCol, &pCodec);
          for(i=0; rc==SQLITE4_OK && i<pInfo->nCol; i++){
            rc = sqlite4VdbeDecodeValue(pCodec, i, 0, &pCsr->aMem[i]);
          }
          sqlite4VdbeDestroyDecoder(pCodec);
        }

        if( rc==SQLITE4_OK ) pCsr->bMemValid = 1;
      }
    }

        if( rc==SQLITE4_OK ){
          rc = sqlite4KVCursorData(pCsr->pCsr, 0, -1, &aData, &nData);
        }

        if( rc==SQLITE4_OK ){
          int i;
          RowDecoder *pCodec;   /* The decoder object */

          rc = sqlite4VdbeCreateDecoder(db, aData, nData, pInfo->nCol, &pCodec);
          for(i=0; rc==SQLITE4_OK && i<pInfo->nCol; i++){
            rc = sqlite4VdbeExtractColumn(pCodec, i, 0, &pCsr->aMem[i]);
          }
          sqlite4VdbeDestroyDecoder(pCodec);
        }

        if( rc==SQLITE4_OK ) pCsr->bMemValid = 1;
      }
    }

    p->apCsr[iCur] = 0;
  }
  if( SQLITE4_OK==sqlite4VdbeMemGrow(pMem, nByte, 0) ){
    p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->z;
    memset(pCx, 0, sizeof(VdbeCursor));
    pCx->iDb = iDb;
    pCx->nField = nField;
    sqlite4_buffer_init(&pCx->key, p->db->pEnv->pMM);
  }
  return pCx;
}

/*
** Try to convert a value into a numeric representation if we can
** do so without loss of information.  In other words, if the string
................................................................................
** If the OPFLAG_CLEARCACHE bit is set on P5 and P1 is a pseudo-table cursor,
** then the cache of the cursor is reset prior to extracting the column.
** The first OP_Column against a pseudo-table after the value of the content
** register has changed should have this bit set.
*/
case OP_Column: {
  KVCursor *pKVCur;         /* Cursor for current entry in the KV storage */
  ValueDecoder *pCodec;     /* The decoder object */
  int p1;                   /* Index of VdbeCursor to decode */
  VdbeCursor *pC;           /* The VDBE cursor */
  Mem *pDest;               /* Where to write the results */
  const KVByteArray *aData; /* The content to be decoded */
  KVSize nData;             /* Size of aData[] in bytes */
  Mem *pDefault;            /* Default value from P4 */
  Mem *pReg;                /* */
................................................................................
    /* TODO: Fix this somehow... */
    int nField = pC->nField;
    if( pC->pKeyInfo && pC->pKeyInfo->nData ) nField = pC->pKeyInfo->nData;

    rc = sqlite4VdbeCreateDecoder(db, aData, nData, nField, &pCodec);
    if( rc==0 ){
      pDefault = (pOp->p4type==P4_MEM) ? pOp->p4.pMem : 0;
      rc = sqlite4VdbeDecodeValue(pCodec, pOp->p2, pDefault, pDest);
      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
................................................................................
  }else if( pOp->p4type==P4_INT32 ){
    nField = pOp->p4.i;
  }
  assert( pOp->p1>=0 );
  pCur = allocateCursor(p, pOp->p1, nField, iDb, 1);
  if( pCur==0 ) goto no_mem;
  pCur->nullRow = 1;
  pCur->isOrdered = 1;
  pCur->iRoot = p2;
  rc = sqlite4KVStoreOpenCursor(pX, &pCur->pKVCur);
  pCur->pKeyInfo = pKeyInfo;

  /* Set the VdbeCursor.isTable and isIndex variables. Previous versions of
  ** SQLite used to check if the root-page flags were sane at this point
  ** and report database corruption if they were not, but this check has
  ** since moved into the btree layer.  */  
  pCur->isTable = pOp->p4type!=P4_KEYINFO;
  pCur->isIndex = !pCur->isTable;
  break;
}

/* Opcode: OpenEphemeral P1 P2 * P4 P5
**
** Open a new cursor P1 to a transient table.
** The cursor is always opened read/write even if 
................................................................................
          SQLITE4_KVOPEN_TEMPORARY | SQLITE4_KVOPEN_NO_TRANSACTIONS
  );
  if( rc==SQLITE4_OK ) rc = sqlite4KVStoreOpenCursor(pCx->pTmpKV, &pCx->pKVCur);
  if( rc==SQLITE4_OK ) rc = sqlite4KVStoreBegin(pCx->pTmpKV, 2);

  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  if( pCx->pKeyInfo ) pCx->pKeyInfo->enc = ENC(p->db);
  pCx->isIndex = !pCx->isTable;

  pCx->isOrdered = 1;
  break;
}

/* Opcode: OpenSorter P1 P2 * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
................................................................................
  VdbeCursor *pCx;

  assert( pOp->p1>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTableReg = pOp->p2;
  pCx->isTable = 1;
  pCx->isIndex = 0;
  break;
}

/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
................................................................................
**
** P1 must be a cursor open on a PRIMARY KEY index. P3 is a cursor open
** on an auxiliary index on the same table. P3 must be pointing to a valid
** index entry.
**
** This opcode seeks cursor P1 so that it points to the PK index entry
** that corresponds to the same table row as the current entry that 
** cursor P3 points to. The entry must exist. If it does not, this opcode
** throws an SQLITE4_CORRUPT exception.





*/
case OP_SeekPk: {
  KVByteArray *aKey;              /* Key data from cursor pIdx */
  KVSize nKey;                    /* Size of aKey[] in bytes */
  VdbeCursor *pPk;                /* Cursor P1 */
  VdbeCursor *pIdx;               /* Cursor P3 */
  int nShort;                     /* Size of aKey[] without PK fields */
................................................................................
  }else{
    rc = sqlite4KVCursorKey(pIdx->pKVCur, (const KVByteArray **)&aKey, &nKey);
    if( rc!=SQLITE4_OK ) break;
    nShort = sqlite4VdbeShortKey(aKey, nKey, 
        pIdx->pKeyInfo->nField - pIdx->pKeyInfo->nPK, 0
    );
    nVarint = sqlite4VarintLen(pPk->iRoot);
    rc = sqlite4_buffer_resize(&pPk->key, nVarint + nKey - nShort);
    if( rc!=SQLITE4_OK ) break;
    putVarint32((u8 *)(pPk->key.p), pPk->iRoot);
    memcpy(((u8*)pPk->key.p) + nVarint, &aKey[nShort], nKey-nShort);
    assert( pPk->key.n>0 );

#if 0
    rc = sqlite4VdbeCursorMoveto(db, pPk);
#endif
  }

  break;
}

/* Opcode: SeekGe P1 P2 P3 P4 *
**
................................................................................
  KVSize nProbe;                  /* Size of aProbe[] in bytes */
  int dir;                        /* KV search dir (+ve or -ve) */
  const KVByteArray *aKey;        /* Pointer to final cursor key */
  KVSize nKey;                    /* Size of aKey[] in bytes */

  pC = p->apCsr[pOp->p1];
  pC->nullRow = 0;
  pC->key.n = 0;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p2!=0 );
  assert( pC!=0 );
  assert( pC->pseudoTableReg==0 );
  assert( OP_SeekLe == OP_SeekLt+1 );
  assert( OP_SeekGe == OP_SeekLt+2 );
  assert( OP_SeekGt == OP_SeekLt+3 );
  assert( pC->isOrdered );

  /* Encode a database key consisting of the contents of the P4 registers
  ** starting at register P3. Have the vdbecodec module allocate an extra
  ** free byte at the end of the database key (see below).  */
  op = pOp->opcode;
  nField = pOp->p4.i;
  pIn3 = &aMem[pOp->p3];
................................................................................
  KVCursor *pKVCur;
  KVByteArray *aKey;
  KVSize nKey;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->isTable );
  pKVCur = pC->pKVCur;
  rc = sqlite4VdbeEncodeKey(db, aMem+pOp->p2, 1, 1, pC->iRoot, 0,
                            &aKey, &nKey, 0);
  if( rc==SQLITE4_OK ){
    rc = sqlite4KVCursorSeek(pKVCur, aKey, nKey, 0);
    if( rc==SQLITE4_NOTFOUND ) rc = SQLITE4_CORRUPT_BKPT;
  }
................................................................................
  sqlite4_found_count++;
#endif

  alreadyExists = 0;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  pC = p->apCsr[pOp->p1];
  pC->key.n = 0;
  assert( pC!=0 );
  pIn3 = &aMem[pOp->p3];
  assert( pC->pKVCur!=0 );
  assert( pC->isTable==0 || pOp->opcode==OP_NotExists );
  if( pOp->p4.i>0 ){
    rc = sqlite4VdbeEncodeKey(
        db, pIn3, pOp->p4.i, pOp->p4.i + (pOp->p5 & OPFLAG_PARTIALKEY),
        pC->iRoot, pC->pKeyInfo, &pProbe, &nProbe, 0
    );
    pFree = pProbe;
  }else{
................................................................................
** P1 must not be pseudo-table. It has to be a real table.
*/
case OP_Delete: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->key.n==0 );
  rc = sqlite4KVCursorDelete(pC->pKVCur);
  if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
  break;
}

/* Opcode: ResetCount * * * * *
**
................................................................................
  KVSize nKey;
  int n;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  rc = sqlite4VdbeCursorMoveto(db, pC);
  if( rc!=SQLITE4_OK ) break;
  assert( pC->key.n==0 );
  assert( pC->pseudoTableReg==0 );
  if( pC->nullRow ){
    pOut->flags = MEM_Null;
    break;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  }else if( pC->pVtabCursor ){
    pVtab = pC->pVtabCursor->pVtab;

    p->apCsr[iCur] = 0;
  }
  if( SQLITE4_OK==sqlite4VdbeMemGrow(pMem, nByte, 0) ){
    p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->z;
    memset(pCx, 0, sizeof(VdbeCursor));
    pCx->iDb = iDb;
    pCx->nField = nField;
    sqlite4_buffer_init(&pCx->sSeekKey, p->db->pEnv->pMM);
  }
  return pCx;
}

/*
** Try to convert a value into a numeric representation if we can
** do so without loss of information.  In other words, if the string
................................................................................
** If the OPFLAG_CLEARCACHE bit is set on P5 and P1 is a pseudo-table cursor,
** then the cache of the cursor is reset prior to extracting the column.
** The first OP_Column against a pseudo-table after the value of the content
** register has changed should have this bit set.
*/
case OP_Column: {
  KVCursor *pKVCur;         /* Cursor for current entry in the KV storage */
  RowDecoder *pCodec;       /* The decoder object */
  int p1;                   /* Index of VdbeCursor to decode */
  VdbeCursor *pC;           /* The VDBE cursor */
  Mem *pDest;               /* Where to write the results */
  const KVByteArray *aData; /* The content to be decoded */
  KVSize nData;             /* Size of aData[] in bytes */
  Mem *pDefault;            /* Default value from P4 */
  Mem *pReg;                /* */
................................................................................
    /* TODO: Fix this somehow... */
    int nField = pC->nField;
    if( pC->pKeyInfo && pC->pKeyInfo->nData ) nField = pC->pKeyInfo->nData;

    rc = sqlite4VdbeCreateDecoder(db, aData, nData, nField, &pCodec);
    if( rc==0 ){
      pDefault = (pOp->p4type==P4_MEM) ? pOp->p4.pMem : 0;
      rc = sqlite4VdbeExtractColumn(pCodec, pOp->p2, pDefault, pDest);
      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
................................................................................
  }else if( pOp->p4type==P4_INT32 ){
    nField = pOp->p4.i;
  }
  assert( pOp->p1>=0 );
  pCur = allocateCursor(p, pOp->p1, nField, iDb, 1);
  if( pCur==0 ) goto no_mem;
  pCur->nullRow = 1;

  pCur->iRoot = p2;
  rc = sqlite4KVStoreOpenCursor(pX, &pCur->pKVCur);
  pCur->pKeyInfo = pKeyInfo;







  break;
}

/* Opcode: OpenEphemeral P1 P2 * P4 P5
**
** Open a new cursor P1 to a transient table.
** The cursor is always opened read/write even if 
................................................................................
          SQLITE4_KVOPEN_TEMPORARY | SQLITE4_KVOPEN_NO_TRANSACTIONS
  );
  if( rc==SQLITE4_OK ) rc = sqlite4KVStoreOpenCursor(pCx->pTmpKV, &pCx->pKVCur);
  if( rc==SQLITE4_OK ) rc = sqlite4KVStoreBegin(pCx->pTmpKV, 2);

  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  if( pCx->pKeyInfo ) pCx->pKeyInfo->enc = ENC(p->db);



  break;
}

/* Opcode: OpenSorter P1 P2 * P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
................................................................................
  VdbeCursor *pCx;

  assert( pOp->p1>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTableReg = pOp->p2;


  break;
}

/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
................................................................................
**
** P1 must be a cursor open on a PRIMARY KEY index. P3 is a cursor open
** on an auxiliary index on the same table. P3 must be pointing to a valid
** index entry.
**
** This opcode seeks cursor P1 so that it points to the PK index entry
** that corresponds to the same table row as the current entry that 
** cursor P3 points to. The entry must exist.
**
** Actually, the seek is deferred until it is actually needed and if the
** PRIMARY KEY index is never referenced, the seek never takes place.  The
** sqlite3VdbeCursorMoveto() does the seek, if necessary.  If the target
** row does not exist in the PRIMARY KEY table, then the
** sqlite3VdbeCursorMoveto() routine will throw an SQLITE4_CORRUPT error.
*/
case OP_SeekPk: {
  KVByteArray *aKey;              /* Key data from cursor pIdx */
  KVSize nKey;                    /* Size of aKey[] in bytes */
  VdbeCursor *pPk;                /* Cursor P1 */
  VdbeCursor *pIdx;               /* Cursor P3 */
  int nShort;                     /* Size of aKey[] without PK fields */
................................................................................
  }else{
    rc = sqlite4KVCursorKey(pIdx->pKVCur, (const KVByteArray **)&aKey, &nKey);
    if( rc!=SQLITE4_OK ) break;
    nShort = sqlite4VdbeShortKey(aKey, nKey, 
        pIdx->pKeyInfo->nField - pIdx->pKeyInfo->nPK, 0
    );
    nVarint = sqlite4VarintLen(pPk->iRoot);
    rc = sqlite4_buffer_resize(&pPk->sSeekKey, nVarint + nKey - nShort);
    if( rc!=SQLITE4_OK ) break;
    putVarint32((u8 *)(pPk->sSeekKey.p), pPk->iRoot);
    memcpy(((u8*)pPk->sSeekKey.p) + nVarint, &aKey[nShort], nKey-nShort);
    assert( pPk->sSeekKey.n>0 );




  }

  break;
}

/* Opcode: SeekGe P1 P2 P3 P4 *
**
................................................................................
  KVSize nProbe;                  /* Size of aProbe[] in bytes */
  int dir;                        /* KV search dir (+ve or -ve) */
  const KVByteArray *aKey;        /* Pointer to final cursor key */
  KVSize nKey;                    /* Size of aKey[] in bytes */

  pC = p->apCsr[pOp->p1];
  pC->nullRow = 0;
  pC->sSeekKey.n = 0;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p2!=0 );
  assert( pC!=0 );
  assert( pC->pseudoTableReg==0 );
  assert( OP_SeekLe == OP_SeekLt+1 );
  assert( OP_SeekGe == OP_SeekLt+2 );
  assert( OP_SeekGt == OP_SeekLt+3 );


  /* Encode a database key consisting of the contents of the P4 registers
  ** starting at register P3. Have the vdbecodec module allocate an extra
  ** free byte at the end of the database key (see below).  */
  op = pOp->opcode;
  nField = pOp->p4.i;
  pIn3 = &aMem[pOp->p3];
................................................................................
  KVCursor *pKVCur;
  KVByteArray *aKey;
  KVSize nKey;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );

  pKVCur = pC->pKVCur;
  rc = sqlite4VdbeEncodeKey(db, aMem+pOp->p2, 1, 1, pC->iRoot, 0,
                            &aKey, &nKey, 0);
  if( rc==SQLITE4_OK ){
    rc = sqlite4KVCursorSeek(pKVCur, aKey, nKey, 0);
    if( rc==SQLITE4_NOTFOUND ) rc = SQLITE4_CORRUPT_BKPT;
  }
................................................................................
  sqlite4_found_count++;
#endif

  alreadyExists = 0;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  pC = p->apCsr[pOp->p1];
  pC->sSeekKey.n = 0;
  assert( pC!=0 );
  pIn3 = &aMem[pOp->p3];
  assert( pC->pKVCur!=0 );

  if( pOp->p4.i>0 ){
    rc = sqlite4VdbeEncodeKey(
        db, pIn3, pOp->p4.i, pOp->p4.i + (pOp->p5 & OPFLAG_PARTIALKEY),
        pC->iRoot, pC->pKeyInfo, &pProbe, &nProbe, 0
    );
    pFree = pProbe;
  }else{
................................................................................
** P1 must not be pseudo-table. It has to be a real table.
*/
case OP_Delete: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->sSeekKey.n==0 );
  rc = sqlite4KVCursorDelete(pC->pKVCur);
  if( pOp->p2 & OPFLAG_NCHANGE ) p->nChange++;
  break;
}

/* Opcode: ResetCount * * * * *
**
................................................................................
  KVSize nKey;
  int n;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  rc = sqlite4VdbeCursorMoveto(db, pC);
  if( rc!=SQLITE4_OK ) break;
  assert( pC->sSeekKey.n==0 );
  assert( pC->pseudoTableReg==0 );
  if( pC->nullRow ){
    pOut->flags = MEM_Null;
    break;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  }else if( pC->pVtabCursor ){
    pVtab = pC->pVtabCursor->pVtab;

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Opaque type used by the explainer */
typedef struct Explain Explain;

/* Opaque type used by vdbecodec.c */
typedef struct ValueDecoder ValueDecoder;

/*
** A cursor is a pointer into a single database.
** The cursor can seek to an entry with a particular key, or
** loop over all entries.  You can also insert new
** entries or retrieve the key or data from the entry that the cursor
** is currently pointing to.
** 
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct VdbeCursor {
  KVCursor *pKVCur;     /* The cursor structure of the backend */
  KVStore *pTmpKV;      /* Separate file holding a temporary table */
  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
  int iRoot;            /* Root page of the table */
  int pseudoTableReg;   /* Register holding pseudotable content. */
  int nField;           /* Number of fields in the header */
  Bool zeroed;          /* True if zeroed out and ready for reuse */
  Bool atFirst;         /* True if pointing to first entry */
  Bool nullRow;         /* True if pointing to a row with no data */
  Bool isTable;         /* True if a table requiring integer keys */
  Bool isIndex;         /* True if an index containing keys only - no data */
  Bool isOrdered;       /* True if the underlying table is BTREE_UNORDERED */
  sqlite4_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  const sqlite4_module *pModule;     /* Module for cursor pVtabCursor */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred move-to */
  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */
  Fts5Cursor *pFts;     /* Fts5 cursor object (or NULL) */



  sqlite4_buffer key;

  /* Result of last sqlite4-Moveto() done by an OP_NotExists or 
  ** OP_IsUnique opcode on this cursor. */
  int seekResult;
};

/*
** When a sub-program is executed (OP_Program), a structure of this type
** is allocated to store the current value of the program counter, as
** well as the current memory cell array and various other frame specific
** values stored in the Vdbe struct. When the sub-program is finished, 
................................................................................
  sqlite4 *db;        /* The associated database connection */
  char *z;            /* String or BLOB value */
  union {
    sqlite4_num num;    /* Numeric value used by MEM_Int and/or MEM_Real */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */

  } u;
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  type;           /* One of SQLITE4_NULL, _TEXT, _INTEGER, etc */
  u8  enc;            /* SQLITE4_UTF8, SQLITE4_UTF16BE, SQLITE4_UTF16LE */
#ifdef SQLITE4_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
................................................................................
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_RowSet    0x0020   /* Value is a RowSet object */
#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
#define MEM_Invalid   0x0080   /* Value is undefined */
#define MEM_TypeMask  0x00ff   /* Mask of type bits */











/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z.  The MEM_Term flag tells us whether or not the
** string is \000 or \u0000 terminated
*/
................................................................................
void sqlite4VdbeDeleteAuxData(VdbeFunc*, int);

int sqlite4VdbeCreateDecoder(
  sqlite4 *db,                /* The database connection */
  const unsigned char *aIn,   /* The input data blob */
  int nIn,                    /* Number of bytes in aIn[] */
  int mxCol,                  /* Maximum number of columns in aIn[] */
  ValueDecoder **ppOut        /* The newly generated decoder object */
);
int sqlite4VdbeDestroyDecoder(ValueDecoder *pDecoder);
int sqlite4VdbeDecodeValue(
  ValueDecoder *pDecoder,      /* The decoder for the whole string */
  int iVal,                    /* Index of the value to decode.  First is 0 */
  Mem *pDefault,               /* The default value.  Often NULL */
  Mem *pOut                    /* Write the result here */
);
int sqlite4VdbeEncodeData(
  sqlite4 *db,                /* The database connection */
  Mem *aIn,                   /* Array of values to encode */

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Opaque type used by the explainer */
typedef struct Explain Explain;

/* Opaque type used by vdbecodec.c */
typedef struct RowDecoder RowDecoder;

/*
** A cursor is a pointer into a single database.
** The cursor can seek to an entry with a particular key, or
** loop over all entries.  You can also insert new
** entries or retrieve the key or data from the entry that the cursor
** is currently pointing to.
** 
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
*/
struct VdbeCursor {
  KVCursor *pKVCur;     /* The cursor structure of the storage engine */
  KVStore *pTmpKV;      /* Separate file holding a temporary table */
  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */
  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */
  int iRoot;            /* Root page of the table */
  int pseudoTableReg;   /* Register holding pseudotable content. */
  int nField;           /* Number of fields in the header */


  Bool nullRow;         /* True if pointing to a row with no data */





  i64 seqCount;         /* Sequence counter */

  VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */
  Fts5Cursor *pFts;     /* Fts5 cursor object (or NULL) */

  sqlite4_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  const sqlite4_module *pModule;     /* Module for cursor pVtabCursor */
  sqlite4_buffer sSeekKey;           /* Key for deferred seek */




};

/*
** When a sub-program is executed (OP_Program), a structure of this type
** is allocated to store the current value of the program counter, as
** well as the current memory cell array and various other frame specific
** values stored in the Vdbe struct. When the sub-program is finished, 
................................................................................
  sqlite4 *db;        /* The associated database connection */
  char *z;            /* String or BLOB value */
  union {
    sqlite4_num num;    /* Numeric value used by MEM_Int and/or MEM_Real */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
    RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
    sqlite4_int64 iOfst;/* Used when flags==MEM_FromKey */
  } u;
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  type;           /* One of SQLITE4_NULL, _TEXT, _INTEGER, etc */
  u8  enc;            /* SQLITE4_UTF8, SQLITE4_UTF16BE, SQLITE4_UTF16LE */
#ifdef SQLITE4_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
................................................................................
#define MEM_Str       0x0002   /* Value is a string */
#define MEM_Int       0x0004   /* Value is an integer */
#define MEM_Real      0x0008   /* Value is a real number */
#define MEM_Blob      0x0010   /* Value is a BLOB */
#define MEM_RowSet    0x0020   /* Value is a RowSet object */
#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
#define MEM_Invalid   0x0080   /* Value is undefined */
#define MEM_TypeMask  0x01ff   /* Mask of type bits */

/*
** The following flag is used in the return from sqlite4VdbeDecodeValue()
** to signal that the value is stored in the key of the record.  If this
** bit is set and then the Mem.n field holds an offset into the key for
** the start of the value.  If Mem.type is set to SQLITE_REAL then numeric
** keys are interpreted as real numbers instead of integers.
*/
#define MEM_FromKey   0x0100   /* Actual value stored in key */


/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z.  The MEM_Term flag tells us whether or not the
** string is \000 or \u0000 terminated
*/
................................................................................
void sqlite4VdbeDeleteAuxData(VdbeFunc*, int);

int sqlite4VdbeCreateDecoder(
  sqlite4 *db,                /* The database connection */
  const unsigned char *aIn,   /* The input data blob */
  int nIn,                    /* Number of bytes in aIn[] */
  int mxCol,                  /* Maximum number of columns in aIn[] */
  RowDecoder **ppOut          /* The newly generated decoder object */
);
int sqlite4VdbeDestroyDecoder(RowDecoder *pDecoder);
int sqlite4VdbeExtractColumn(
  RowDecoder *pDecoder,        /* The decoder for the whole string */
  int iVal,                    /* Index of the value to decode.  First is 0 */
  Mem *pDefault,               /* The default value.  Often NULL */
  Mem *pOut                    /* Write the result here */
);
int sqlite4VdbeEncodeData(
  sqlite4 *db,                /* The database connection */
  Mem *aIn,                   /* Array of values to encode */

  sqlite4Fts5Close(pCx->pFts);
  if( pCx->pKVCur ){
    sqlite4KVCursorClose(pCx->pKVCur);
  }
  if( pCx->pTmpKV ){
    sqlite4KVStoreClose(pCx->pTmpKV);
  }
  sqlite4_buffer_clear(&pCx->key);
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if( pCx->pVtabCursor ){
    sqlite4_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
    const sqlite4_module *pModule = pCx->pModule;
    p->inVtabMethod = 1;
    pModule->xClose(pVtabCursor);
    p->inVtabMethod = 0;
................................................................................
**
** If the operation is a success, SQLITE4_OK is returned. Or, if the
** required entry is not found in the PK index, SQLITE4_CORRUPT. Or if 
** some other error occurs, an error code is returned.
*/
int sqlite4VdbeCursorMoveto(sqlite4 *db, VdbeCursor *pPk){
  int rc = SQLITE4_OK;            /* Return code */
  if( pPk->key.n!=0 ){
    assert( pPk->pKeyInfo->nPK==0 );
    rc = sqlite4KVCursorSeek(pPk->pKVCur, pPk->key.p, pPk->key.n, 0);
    if( rc==SQLITE4_NOTFOUND ){
      rc = SQLITE4_CORRUPT_BKPT;
    }
    pPk->nullRow = 0;
    pPk->key.n = 0;
  }
  return rc;
}

  sqlite4Fts5Close(pCx->pFts);
  if( pCx->pKVCur ){
    sqlite4KVCursorClose(pCx->pKVCur);
  }
  if( pCx->pTmpKV ){
    sqlite4KVStoreClose(pCx->pTmpKV);
  }
  sqlite4_buffer_clear(&pCx->sSeekKey);
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if( pCx->pVtabCursor ){
    sqlite4_vtab_cursor *pVtabCursor = pCx->pVtabCursor;
    const sqlite4_module *pModule = pCx->pModule;
    p->inVtabMethod = 1;
    pModule->xClose(pVtabCursor);
    p->inVtabMethod = 0;
................................................................................
**
** If the operation is a success, SQLITE4_OK is returned. Or, if the
** required entry is not found in the PK index, SQLITE4_CORRUPT. Or if 
** some other error occurs, an error code is returned.
*/
int sqlite4VdbeCursorMoveto(sqlite4 *db, VdbeCursor *pPk){
  int rc = SQLITE4_OK;            /* Return code */
  if( pPk->sSeekKey.n!=0 ){
    assert( pPk->pKeyInfo->nPK==0 );
    rc = sqlite4KVCursorSeek(pPk->pKVCur, pPk->sSeekKey.p, pPk->sSeekKey.n, 0);
    if( rc==SQLITE4_NOTFOUND ){
      rc = SQLITE4_CORRUPT_BKPT;
    }
    pPk->nullRow = 0;
    pPk->sSeekKey.n = 0;
  }
  return rc;
}

** insertion and reading from the key/value storage engine.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The decoder object.









*/
struct ValueDecoder {
  sqlite4 *db;                /* The database connection */
  const u8 *a;                /* Content to be decoded */
  int n;                      /* Bytes of content in a[] */
  int mxCol;                  /* Maximum number of columns */
};

/*
................................................................................
** The aIn[] value must remain stable for the life of the decoder.
*/
int sqlite4VdbeCreateDecoder(
  sqlite4 *db,                /* The database connection */
  const unsigned char *aIn,   /* The input data blob */
  int nIn,                    /* Number of bytes in aIn[] */
  int mxCol,                  /* Maximum number of columns in aIn[] */
  ValueDecoder **ppOut        /* The newly generated decoder object */
){
  ValueDecoder *p;

  p = sqlite4DbMallocZero(db, sizeof(*p));
  *ppOut = p;
  if( p==0 ) return SQLITE4_NOMEM;
  p->db = db;
  p->a = aIn;
  p->n = nIn;
................................................................................
  return SQLITE4_OK;
}

/*
** Destroy a decoder object previously created
** using sqlite4VdbeCreateDecoder().
*/
int sqlite4VdbeDestroyDecoder(ValueDecoder *p){
  if( p ){
    sqlite4DbFree(p->db, p);
  }
  return SQLITE4_OK;
}

/*
** Decode a single value from a data string.






*/
int sqlite4VdbeDecodeValue(
  ValueDecoder *p,             /* The decoder for the whole string */
  int iVal,                    /* Index of the value to decode.  First is 0 */
  Mem *pDefault,               /* The default value.  Often NULL */
  Mem *pOut                    /* Write the result here */
){
  u32 size;                    /* Size of a field */
  sqlite4_uint64 ofst;         /* Offset to the payload */
  sqlite4_uint64 type;         /* Datatype */
................................................................................

      num.m = x;
      num.e = (e >> 2);
      if( e & 0x02 ) num.e = -1 * num.e;
      if( e & 0x01 ) num.sign = 1;
      pOut->u.num = num;
      MemSetTypeFlag(pOut, MEM_Real);





    }else if( cclass==0 ){
      if( size==0 ){
        sqlite4VdbeMemSetStr(pOut, "", 0, SQLITE4_UTF8, SQLITE4_TRANSIENT, 0);
      }else if( p->a[ofst]>0x02 ){
        sqlite4VdbeMemSetStr(pOut, (char*)(p->a+ofst), size, 
                             SQLITE4_UTF8, SQLITE4_TRANSIENT, 0);
      }else{

** insertion and reading from the key/value storage engine.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The decoder object.
**
** An instance of this object is used to extract individual columns (numbers,
** strings, blobs, or NULLs) from a row of a table or index.  Usually the
** content is extract from the value side of the key/value pair, though
** sometimes information might be taken from the key as well.
**
** When the VDBE needs to extract multiple columns from the same row, it will
** try to reuse a single decoder object.  The decoder, therefore, should attempt
** to cache any intermediate results that might be useful on later invocations.
*/
struct RowDecoder {
  sqlite4 *db;                /* The database connection */
  const u8 *a;                /* Content to be decoded */
  int n;                      /* Bytes of content in a[] */
  int mxCol;                  /* Maximum number of columns */
};

/*
................................................................................
** The aIn[] value must remain stable for the life of the decoder.
*/
int sqlite4VdbeCreateDecoder(
  sqlite4 *db,                /* The database connection */
  const unsigned char *aIn,   /* The input data blob */
  int nIn,                    /* Number of bytes in aIn[] */
  int mxCol,                  /* Maximum number of columns in aIn[] */
  RowDecoder **ppOut          /* The newly generated decoder object */
){
  RowDecoder *p;

  p = sqlite4DbMallocZero(db, sizeof(*p));
  *ppOut = p;
  if( p==0 ) return SQLITE4_NOMEM;
  p->db = db;
  p->a = aIn;
  p->n = nIn;
................................................................................
  return SQLITE4_OK;
}

/*
** Destroy a decoder object previously created
** using sqlite4VdbeCreateDecoder().
*/
int sqlite4VdbeDestroyDecoder(RowDecoder *p){
  if( p ){
    sqlite4DbFree(p->db, p);
  }
  return SQLITE4_OK;
}

/*
** Decode a single value from a data string.  Store that value in pOut.
**
** If the value is a FROM-KEY reference (header codes 22 and 23) then the
** pOut->flags field is set to MEM_FromKey and pOut->iOfst is the offset into
** the key of the start of the actual value.  The pOut->type field is set to
** SQLITE_FLOAT if a numeric value extracted from the key should be interpreted
** as a floating point even if it has no fractional part.
*/
int sqlite4VdbeExtractColumn(
  RowDecoder *p,             /* The decoder for the whole string */
  int iVal,                    /* Index of the value to decode.  First is 0 */
  Mem *pDefault,               /* The default value.  Often NULL */
  Mem *pOut                    /* Write the result here */
){
  u32 size;                    /* Size of a field */
  sqlite4_uint64 ofst;         /* Offset to the payload */
  sqlite4_uint64 type;         /* Datatype */
................................................................................

      num.m = x;
      num.e = (e >> 2);
      if( e & 0x02 ) num.e = -1 * num.e;
      if( e & 0x01 ) num.sign = 1;
      pOut->u.num = num;
      MemSetTypeFlag(pOut, MEM_Real);

    }else if( type<=23 ){
      MemSetTypeFlag(pOut, MEM_FromKey);
      pOut->u.iOfst = subtype;
      pOut->type = type==23 ? SQLITE4_FLOAT : SQLITE4_INTEGER;
    }else if( cclass==0 ){
      if( size==0 ){
        sqlite4VdbeMemSetStr(pOut, "", 0, SQLITE4_UTF8, SQLITE4_TRANSIENT, 0);
      }else if( p->a[ofst]>0x02 ){
        sqlite4VdbeMemSetStr(pOut, (char*)(p->a+ofst), size, 
                             SQLITE4_UTF8, SQLITE4_TRANSIENT, 0);
      }else{