SQLite

** area.  pCell might point to some temporary storage.  The cell will
** be constructed in this temporary area then copied into pPage->aData
** later.
*/
static int fillInCell(
  MemPage *pPage,                /* The page that contains the cell */
  unsigned char *pCell,          /* Complete text of the cell */


  const BtreePayload *pX,        /* Payload with which to construct the cell */
  int *pnSize                    /* Write cell size here */
){
  int nPayload;
  const u8 *pSrc;
  int nSrc, n, rc;
  int spaceLeft;
  MemPage *pOvfl = 0;

  /* pPage is not necessarily writeable since pCell might be auxiliary
  ** buffer space that is separate from the pPage buffer area */
  assert( pCell<pPage->aData || pCell>=&pPage->aData[pBt->pageSize]
            || sqlite3PagerIswriteable(pPage->pDbPage) );

  /* Fill in the header. */
  nHeader = pPage->childPtrSize;
  nPayload = pX->nData + pX->nZero;
  if( pPage->intKeyLeaf ){
    nHeader += putVarint32(&pCell[nHeader], nPayload);
  }else{
    assert( pX->nData==0 );
    assert( pX->nZero==0 );
  }
  nHeader += putVarint(&pCell[nHeader], *(u64*)&pX->nKey);
  
  /* Fill in the payload */
  if( pPage->intKey ){
    pSrc = pX->pData;
    nSrc = pX->nData;
  }else{ 
    assert( pX->nKey<=0x7fffffff && pX->pKey!=0 );
    nSrc = nPayload = (int)pX->nKey;
    pSrc = pX->pKey;

  }
  if( nPayload<=pPage->maxLocal ){
    n = nHeader + nPayload;
    testcase( n==3 );
    testcase( n==4 );
    if( n<4 ) n = 4;
    *pnSize = n;

  ** were computed correctly.
  */
#if SQLITE_DEBUG
  {
    CellInfo info;
    pPage->xParseCell(pPage, pCell, &info);
    assert( nHeader==(int)(info.pPayload - pCell) );
    assert( info.nKey==pX->nKey );
    assert( *pnSize == info.nSize );
    assert( spaceLeft == info.nLocal );
  }
#endif

  /* Write the payload into the local Cell and any extra into overflow pages */
  while( nPayload>0 ){

    sqlite3PageFree(pFree);
  }
  return rc;
}


/*
** Insert a new record into the BTree.  The content of the new record
** is described by the pX object.  The pCur cursor is used only to
** define what table the record should be inserted into, and is left
** pointing at a random location.
**
** For a table btree (used for rowid tables), only the pX.nKey value of
** the key is used. The pX.pKey value must be NULL.  The pX.nKey is the

** rowid or INTEGER PRIMARY KEY of the row.  The pX.nData,pData,nZero fields
** hold the content of the row.
**
** For an index btree (used for indexes and WITHOUT ROWID tables), the
** key is an arbitrary byte sequence stored in pX.pKey,nKey.  The 
** pX.pData,nData,nZero fields must be zero.
**
** If the seekResult parameter is non-zero, then a successful call to
** MovetoUnpacked() to seek cursor pCur to (pKey, nKey) has already
** been performed. seekResult is the search result returned (a negative
** number if pCur points at an entry that is smaller than (pKey, nKey), or
** a positive value if pCur points at an entry that is larger than 
** (pKey, nKey)). 
**
** If the seekResult parameter is non-zero, then the caller guarantees that
** cursor pCur is pointing at the existing copy of a row that is to be
** overwritten.  If the seekResult parameter is 0, then cursor pCur may
** point to any entry or to no entry at all and so this function has to seek
** the cursor before the new key can be inserted.
*/
int sqlite3BtreeInsert(
  BtCursor *pCur,                /* Insert data into the table of this cursor */


  const BtreePayload *pX,        /* Content of the row to be inserted */
  int appendBias,                /* True if this is likely an append */
  int seekResult                 /* Result of prior MovetoUnpacked() call */
){
  int rc;
  int loc = seekResult;          /* -1: before desired location  +1: after */
  int szNew = 0;
  int idx;

  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
  ** blob of associated data.  */
  assert( (pX->pKey==0)==(pCur->pKeyInfo==0) );

  /* Save the positions of any other cursors open on this table.
  **
  ** In some cases, the call to btreeMoveto() below is a no-op. For
  ** example, when inserting data into a table with auto-generated integer
  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the 
  ** integer key to use. It then calls this function to actually insert the 
  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
  ** that the cursor is already where it needs to be and returns without
  ** doing any work. To avoid thwarting these optimizations, it is important
  ** not to clear the cursor here.
  */
  if( pCur->curFlags & BTCF_Multiple ){
    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
    if( rc ) return rc;
  }

  if( pCur->pKeyInfo==0 ){
    assert( pX->pKey==0 );
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, pX->nKey, 0);

    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary
    ** btreeMoveto() call */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey>0
      && pCur->info.nKey==pX->nKey-1 ){
       loc = -1;
    }else if( loc==0 ){
      rc = sqlite3BtreeMovetoUnpacked(pCur, 0, pX->nKey, appendBias, &loc);
      if( rc ) return rc;
    }
  }else if( loc==0 ){
    rc = btreeMoveto(pCur, pX->pKey, pX->nKey, appendBias, &loc);
    if( rc ) return rc;
  }
  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->intKey || pX->nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, pX->nKey, pX->nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );
  newCell = pBt->pTmpSpace;
  assert( newCell!=0 );
  rc = fillInCell(pPage, newCell, pX, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==pPage->xCellSize(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(pBt) );
  idx = pCur->aiIdx[pCur->iPage];
  if( loc==0 ){
    u16 szOld;
    assert( idx<pPage->nCell );

/*
** Forward declarations of structure
*/
typedef struct Btree Btree;
typedef struct BtCursor BtCursor;
typedef struct BtShared BtShared;
typedef struct BtreePayload BtreePayload;


int sqlite3BtreeOpen(
  sqlite3_vfs *pVfs,       /* VFS to use with this b-tree */
  const char *zFilename,   /* Name of database file to open */
  sqlite3 *db,             /* Associated database connection */
  Btree **ppBtree,         /* Return open Btree* here */

int sqlite3BtreeCursorRestore(BtCursor*, int*);
int sqlite3BtreeDelete(BtCursor*, u8 flags);

/* Allowed flags for the 2nd argument to sqlite3BtreeDelete() */
#define BTREE_SAVEPOSITION 0x02  /* Leave cursor pointing at NEXT or PREV */
#define BTREE_AUXDELETE    0x04  /* not the primary delete operation */

/* An instance of the BtreePayload object describes the content of a single
** entry in either an index or table btree.
**
** Index btrees (used for indexes and also WITHOUT ROWID tables) contain
** an arbitrary key and no data.  These btrees have pKey,nKey set to their
** key and pData,nData,nZero set to zero.
**
** Table btrees (used for rowid tables) contain an integer rowid used as
** the key and passed in the nKey field.  The pKey field is zero.  
** pData,nData hold the content of the new entry.  nZero extra zero bytes
** are appended to the end of the content when constructing the entry.
**
** This object is used to pass information into sqlite3BtreeInsert().  The
** same information used to be passed as five separate parameters.  But placing
** the information into this object helps to keep the interface more 
** organized and understandable, and it also helps the resulting code to
** run a little faster by using fewer registers for parameter passing.
*/
struct BtreePayload {
  const void *pKey;       /* Key content for indexes.  NULL for tables */
  sqlite3_int64 nKey;     /* Size of pKey for indexes.  PRIMARY KEY for tabs */
  const void *pData;      /* Data for tables.  NULL for indexes */
  int nData;              /* Size of pData.  0 if none. */
  int nZero;              /* Extra zero data appended after pData,nData */
};

int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload,

                       int bias, int seekResult);
int sqlite3BtreeFirst(BtCursor*, int *pRes);
int sqlite3BtreeLast(BtCursor*, int *pRes);
int sqlite3BtreeNext(BtCursor*, int *pRes);
int sqlite3BtreeEof(BtCursor*);
int sqlite3BtreePrevious(BtCursor*, int *pRes);
int sqlite3BtreeKeySize(BtCursor*, i64 *pSize);
int sqlite3BtreeKey(BtCursor*, u32 offset, u32 amt, void*);

  ClientData clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *const objv[]
){
  BtCursor *pCur;
  int rc;
  BtreePayload x;




  if( objc!=4 && objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?-intkey? CSR KEY VALUE");
    return TCL_ERROR;
  }

  memset(&x, 0, sizeof(x));
  if( objc==4 ){
    if( Tcl_GetIntFromObj(interp, objv[2], &rc) ) return TCL_ERROR;
    x.nKey = rc;
    x.pData = (void*)Tcl_GetByteArrayFromObj(objv[3], &x.nData);
  }else{
    x.pKey = (void*)Tcl_GetByteArrayFromObj(objv[2], &rc);
    x.nKey = rc;
  }
  pCur = (BtCursor*)sqlite3TestTextToPtr(Tcl_GetString(objv[1]));

  sqlite3_mutex_enter(pCur->pBtree->db->mutex);
  sqlite3BtreeEnter(pCur->pBtree);
  rc = sqlite3BtreeInsert(pCur, &x, 0, 0);
  sqlite3BtreeLeave(pCur->pBtree);
  sqlite3_mutex_leave(pCur->pBtree->db->mutex);

  Tcl_ResetResult(interp);
  if( rc ){
    Tcl_AppendResult(interp, sqlite3ErrName(rc), 0);
    return TCL_ERROR;

** This works exactly like OP_Insert except that the key is the
** integer value P3, not the value of the integer stored in register P3.
*/
case OP_Insert: 
case OP_InsertInt: {
  Mem *pData;       /* MEM cell holding data for the record to be inserted */
  Mem *pKey;        /* MEM cell holding key  for the record */

  VdbeCursor *pC;   /* Cursor to table into which insert is written */

  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
  const char *zDb;  /* database name - used by the update hook */
  Table *pTab;      /* Table structure - used by update and pre-update hooks */
  int op;           /* Opcode for update hook: SQLITE_UPDATE or SQLITE_INSERT */
  BtreePayload x;   /* Payload to be inserted */

  op = 0;
  pData = &aMem[pOp->p2];
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( memIsValid(pData) );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable );
  assert( pOp->p4type==P4_TABLE || pOp->p4type>=P4_STATIC );
  REGISTER_TRACE(pOp->p2, pData);

  if( pOp->opcode==OP_Insert ){
    pKey = &aMem[pOp->p3];
    assert( pKey->flags & MEM_Int );
    assert( memIsValid(pKey) );
    REGISTER_TRACE(pOp->p3, pKey);
    x.nKey = pKey->u.i;
  }else{
    assert( pOp->opcode==OP_InsertInt );
    x.nKey = pOp->p3;
  }

  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
    assert( pC->isTable );
    assert( pC->iDb>=0 );
    zDb = db->aDb[pC->iDb].zName;
    pTab = pOp->p4.pTab;
    assert( HasRowid(pTab) );
    op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
  }else{
    pTab = 0; /* Not needed.  Silence a comiler warning. */
    zDb = 0;  /* Not needed.  Silence a compiler warning. */
  }

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  /* Invoke the pre-update hook, if any */
  if( db->xPreUpdateCallback 
   && pOp->p4type==P4_TABLE
   && !(pOp->p5 & OPFLAG_ISUPDATE)
  ){
    sqlite3VdbePreUpdateHook(p, pC, SQLITE_INSERT, zDb, pTab, x.nKey, pOp->p2);
  }
#endif

  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = lastRowid = x.nKey;
  if( pData->flags & MEM_Null ){
    x.pData = 0;
    x.nData = 0;
  }else{
    assert( pData->flags & (MEM_Blob|MEM_Str) );
    x.pData = pData->z;
    x.nData = pData->n;
  }
  seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
  if( pData->flags & MEM_Zero ){
    x.nZero = pData->u.nZero;
  }else{
    x.nZero = 0;
  }
  x.pKey = 0;
  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,

                          (pOp->p5 & OPFLAG_APPEND)!=0, seekResult
  );
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;

  /* Invoke the update-hook if required. */
  if( rc ) goto abort_due_to_error;
  if( db->xUpdateCallback && op ){
    db->xUpdateCallback(db->pUpdateArg, op, zDb, pTab->zName, x.nKey);
  }
  break;
}

/* Opcode: Delete P1 P2 P3 P4 P5
**
** Delete the record at which the P1 cursor is currently pointing.

**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_SorterInsert:       /* in2 */
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;
  BtreePayload x;


  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( isSorter(pC)==(pOp->opcode==OP_SorterInsert) );
  pIn2 = &aMem[pOp->p2];
  assert( pIn2->flags & MEM_Blob );
  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  assert( pC->eCurType==CURTYPE_BTREE || pOp->opcode==OP_SorterInsert );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc ) goto abort_due_to_error;
  if( pOp->opcode==OP_SorterInsert ){
    rc = sqlite3VdbeSorterWrite(pC, pIn2);
  }else{
    x.nKey = pIn2->n;
    x.pKey = pIn2->z;
    x.nData = 0;
    x.nZero = 0;
    x.pData = 0;
    rc = sqlite3BtreeInsert(pC->uc.pCursor, &x, pOp->p3, 
        ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
        );
    assert( pC->deferredMoveto==0 );
    pC->cacheStatus = CACHE_STALE;
  }
  if( rc) goto abort_due_to_error;
  break;