SQLite

** register used by the autoincrement tracker.  
*/
void sqlite3AutoincrementBegin(Parse *pParse){
  AutoincInfo *p;            /* Information about an AUTOINCREMENT */
  sqlite3 *db = pParse->db;  /* The database connection */
  Db *pDb;                   /* Database only autoinc table */
  int memId;                 /* Register holding max rowid */

  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */

  /* This routine is never called during trigger-generation.  It is
  ** only called from the top-level */
  assert( pParse->pTriggerTab==0 );
  assert( sqlite3IsToplevel(pParse) );

  assert( v );   /* We failed long ago if this is not so */
  for(p = pParse->pAinc; p; p = p->pNext){
    static const int iLn = VDBE_OFFSET_LINENO(2);
    static const VdbeOpList autoInc[] = {
      /* 0  */ {OP_Null,    0,  0, 0},
      /* 1  */ {OP_Rewind,  0,  9, 0},
      /* 2  */ {OP_Column,  0,  0, 0},
      /* 3  */ {OP_Ne,      0,  7, 0},
      /* 4  */ {OP_Rowid,   0,  0, 0},
      /* 5  */ {OP_Column,  0,  1, 0},
      /* 6  */ {OP_Goto,    0,  9, 0},
      /* 7  */ {OP_Next,    0,  2, 0},
      /* 8  */ {OP_Integer, 0,  0, 0},
      /* 9  */ {OP_Close,   0,  0, 0} 
    };
    VdbeOp *aOp;
    pDb = &db->aDb[p->iDb];
    memId = p->regCtr;
    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);


    sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
    if( aOp==0 ) break;
    aOp[0].p2 = memId;
    aOp[0].p3 = memId+1;
    aOp[2].p3 = memId;
    aOp[3].p1 = memId-1;
    aOp[3].p3 = memId;
    aOp[3].p5 = SQLITE_JUMPIFNULL;
    aOp[4].p2 = memId+1;
    aOp[5].p3 = memId;


    aOp[8].p2 = memId;

  }
}

/*
** Update the maximum rowid for an autoincrement calculation.
**
** This routine should be called when the regRowid register holds a
** new rowid that is about to be inserted.  If that new rowid is
** larger than the maximum rowid in the memId memory cell, then the
** memory cell is updated.
*/
static void autoIncStep(Parse *pParse, int memId, int regRowid){
  if( memId>0 ){
    sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
  }
}

/*
** This routine generates the code needed to write autoincrement
** maximum rowid values back into the sqlite_sequence register.
** Every statement that might do an INSERT into an autoincrement
** table (either directly or through triggers) needs to call this
** routine just before the "exit" code.
*/
static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
  AutoincInfo *p;
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;

  assert( v );
  for(p = pParse->pAinc; p; p = p->pNext){
    static const int iLn = VDBE_OFFSET_LINENO(2);
    static const VdbeOpList autoIncEnd[] = {
      /* 0 */ {OP_NotNull,     0, 2, 0},
      /* 1 */ {OP_NewRowid,    0, 0, 0},
      /* 2 */ {OP_MakeRecord,  0, 2, 0},
      /* 3 */ {OP_Insert,      0, 0, 0},
      /* 4 */ {OP_Close,       0, 0, 0}
    };
    VdbeOp *aOp;
    Db *pDb = &db->aDb[p->iDb];

    int iRec;
    int memId = p->regCtr;

    iRec = sqlite3GetTempReg(pParse);
    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
    if( aOp==0 ) break;
    aOp[0].p1 = memId+1;

    aOp[1].p2 = memId+1;
    aOp[2].p1 = memId-1;
    aOp[2].p3 = iRec;
    aOp[3].p2 = iRec;
    aOp[3].p3 = memId+1;
    aOp[3].p5 = OPFLAG_APPEND;

    sqlite3ReleaseTempReg(pParse, iRec);
  }
}
void sqlite3AutoincrementEnd(Parse *pParse){
  if( pParse->pAinc ) autoIncrementEnd(pParse);
}
#else
/*
** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
** above are all no-ops
*/
# define autoIncBegin(A,B,C) (0)
# define autoIncStep(A,B,C)

#endif /* SQLITE_OMIT_BTREECOUNT */
      } 
    }
    {
      static const int iLn = VDBE_OFFSET_LINENO(2);
      static const VdbeOpList endCode[] = {
        { OP_AddImm,      1, 0,        0},    /* 0 */
        { OP_If,          1, 4,        0},    /* 1 */
        { OP_String8,     0, 3,        0},    /* 2 */
        { OP_ResultRow,   3, 1,        0},    /* 3 */
      };
      VdbeOp *aOp;

      aOp = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode, iLn);
      if( aOp ){
        aOp[0].p2 = -mxErr;

        aOp[2].p4type = P4_STATIC;
        aOp[2].p4.z = "ok";
      }
    }
  }
  break;
#endif /* SQLITE_OMIT_INTEGRITY_CHECK */

};

/*
** During code generation of statements that do inserts into AUTOINCREMENT 
** tables, the following information is attached to the Table.u.autoInc.p
** pointer of each autoincrement table to record some side information that
** the code generator needs.  We have to keep per-table autoincrement
** information in case inserts are done within triggers.  Triggers do not
** normally coordinate their activities, but we do need to coordinate the
** loading and saving of autoincrement information.
*/
struct AutoincInfo {
  AutoincInfo *pNext;   /* Next info block in a list of them all */
  Table *pTab;          /* Table this info block refers to */
  int iDb;              /* Index in sqlite3.aDb[] of database holding pTab */

  p->aOp = 0;
  return aOp;
}

/*
** Add a whole list of operations to the operation stack.  Return a
** pointer to the first operation inserted.
**
** Non-zero P2 arguments to jump instructions are automatically adjusted
** so that the jump target is relative to the first operation inserted.
*/
VdbeOp *sqlite3VdbeAddOpList(
  Vdbe *p,                     /* Add opcodes to the prepared statement */
  int nOp,                     /* Number of opcodes to add */
  VdbeOpList const *aOp,       /* The opcodes to be added */
  int iLineno                  /* Source-file line number of first opcode */
){
  int i;
  VdbeOp *pOut, *pFirst;
  assert( nOp>0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  if( p->nOp + nOp > p->pParse->nOpAlloc && growOpArray(p, nOp) ){
    return 0;
  }
  pFirst = pOut = &p->aOp[p->nOp];
  for(i=0; i<nOp; i++, aOp++, pOut++){
    pOut->opcode = aOp->opcode;
    pOut->p1 = aOp->p1;
    pOut->p2 = aOp->p2;
    assert( aOp->p2>=0 );
    if( (sqlite3OpcodeProperty[aOp->opcode] & OPFLG_JUMP)!=0 && aOp->p2>0 ){
      pOut->p2 += p->nOp;
    }
    pOut->p3 = aOp->p3;
    pOut->p4type = P4_NOTUSED;
    pOut->p4.p = 0;
    pOut->p5 = 0;
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
    pOut->zComment = 0;
#endif

      ** uses it to implement the blob_read(), blob_write() and 
      ** blob_bytes() functions.
      **
      ** The sqlite3_blob_close() function finalizes the vdbe program,
      ** which closes the b-tree cursor and (possibly) commits the 
      ** transaction.
      */
      static const int iLn = VDBE_OFFSET_LINENO(2);
      static const VdbeOpList openBlob[] = {


        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
        {OP_Variable,       1, 1, 0},  /* 2: Move ?1 into reg[1] */
        {OP_NotExists,      0, 7, 1},  /* 3: Seek the cursor */
        {OP_Column,         0, 0, 1},  /* 4  */
        {OP_ResultRow,      1, 0, 0},  /* 5  */
        {OP_Goto,           0, 2, 0},  /* 6  */
        {OP_Close,          0, 0, 0},  /* 7  */
        {OP_Halt,           0, 0, 0},  /* 8  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, 
                           pTab->pSchema->schema_cookie,