if(!(flag & FLAG_DONTINSERT)) {	char *dest2;	/* ***  Do actual insertion on a page  *** */	/*  Set new page length  */	BTPAGE_LENGTH(bt,dest) = n + 1;	dest2 = dest + BTOFF_START(bt) + pos * fLen;	/*  Move contents  */	if(pos < n) memmove(dest2 + fLen,dest2,(n - pos) * fLen);	/*  Set up new element  */	memcpy(dest2 + BTOFF_CONTENT(bt),nCont,bt->BAT_FieldLength);	memcpyl(dest2 + BTOFF_SETNR(bt),&nNumber,sizeof(nNumber));#ifdef CONFIG_BTREE_EXTRALEAF	if(!BTPAGE_ISLEAF(bt,dest))#endif	  memcpyl(dest2 + BTOFF_SUBPAGE(bt),&subPage,sizeof(subPage));      }      subPage = nextSub;      /*  If page was split, set up element to pass to upper level  */      if(next) {	memcpy((char *)nCont,next,bt->BAT_FieldLength);	nNumber = nextSetNr;      }      /*  Finally check if root page was split  */      if((flag & FLAG_DIDPAGESPLIT) && nDepth == 0) {	BTreePage newPage;	char *p2;	if((newPage = (*(bt->BAT_PageAdmin))(bt,-1)) < 0 ||	   (p2 = bayGetPage(bt,newPage,BFILEMODE_DIRTY)) == NULL) {	  if(flag & FLAG_RELEASELOCK) goto error1;	  goto error;	}#ifdef DEBUGI	printf("  Root page %d split, newpage %d\n",nStack[nDepth].BTP_PageNr,	       newPage);#endif	/*  Copy old root page to allocated one and set up new root page.	 *   This procedure ensures that the location of the root page	 *   never changes. The reserved fields are not copied.	 */	memcpy(p2,p1,BTPAGE_SIZE(bt) - bt->BAT_Reserved);	/*  Clear root page, insertion in next iteration	 *   will set it up correctly.	 */	BTPAGE_LENGTH(bt,p1) = 0;	BTPAGE_SUBPAGE0(bt,p1) = newPage;	nStack[nDepth].BTP_Position = 0;      } else	/*  Go to next level of insertion  */	nDepth--;      /*  Release lock for old page  */      if((flag & FLAG_RELEASELOCK) && baySetPage(bt,page1,BFILEMODE_UNPROT) < 0)	goto error;    } else { /* ***  Do DELETION  *** */      char *p1,*p2,*p3,*p;      BTreePage page2,page3;      long pos,fLen,fLen2,currMax,len,flag;      /*  Load page and delete element  */      page1 = oStack[oDepth].BTP_PageNr;      pos  = oStack[oDepth].BTP_Position;      if((p1 = bayGetPage(bt,page1,BFILEMODE_DIRTY)) == NULL) goto error;      if(BTPAGE_ISLEAF(bt,p1)) {	fLen = BTLEN_FIELDL(bt);	currMax = bt->BAT_MaxElementLeaf;      } else {	fLen = BTLEN_FIELD(bt);	currMax = bt->BAT_MaxElement;      }#ifdef DEBUGD      printf("  Delete page %d len %d at pos %d\n",page1,	     BTPAGE_LENGTH(bt,p1),pos);#endif      /*  Decrease number of elements on this page       *   and delete actual element. Must ensure       *   that the subpage element of the one to       *   delete has already been handled.       */      len = --BTPAGE_LENGTH(bt,p1);      p = p1 + BTOFF_START(bt) + pos * fLen;      if(pos < len) memmove(p,p + fLen,(len - pos) * fLen);      /*  Does page have still enough elements?  */      if(len >= (currMax / 2)) {	oDepth = -1; /*  deletion finished  */	continue; /*  continue loop, probably we still have to insert?  */      }      /*  Underflow on root page?  */      if(oDepth == 0) {	/*  If root page is non-empty, stop deleting  */	if(len == 0) {	  /* ***  Special case: Root page is empty  *** */#ifdef DEBUGD	  printf("  Root page empty!\n");#endif	  /*  Get the only remaining leftmost subpage element, which	   *   is the page that will become the new root page.	   */	  memcpyl(&page2,p1 + (BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt)),		  sizeof(page2));	  /*  Empty tree reached?  */	  if(page2 >= 0) {	    /*  Copy the sub page to the root page and free sub page.	     *   This again ensures that the position of the root page	     *   never changes.	     */	    if(baySetPage(bt,page1,BFILEMODE_PROT) < 0) goto error;	    if((p2 = bayGetPage(bt,page2,BFILEMODE_DIRTY)) == NULL)	      goto error1;	    memcpy(p1,p2,BTPAGE_SIZE(bt) - bt->BAT_Reserved);	    /*  Unlock and free page  */	    if(baySetPage(bt,page1,BFILEMODE_UNPROT) < 0 ||	       (*(bt->BAT_PageAdmin))(bt,page2) < 0) goto error;	  }	}	oDepth = -1; /*  deletion finished  */	continue;      }      /* **  Handle page concatenation  **       *       *               page2       *                /\       *               /  \       *              /    \       *           page1  page3       */      /*  Get parent page  */      page2 = oStack[oDepth - 1].BTP_PageNr;      pos   = oStack[oDepth - 1].BTP_Position;      if(baySetPage(bt,page1,BFILEMODE_PROT) < 0) goto error;      if((p2 = bayGetPage(bt,page2,BFILEMODE_DIRTY | BFILEMODE_PROT)) == NULL)	goto error1;      fLen2 = BTLEN_FIELD(bt); /*  page2 cannot be a leaf page  */      /*  Are we at the last position on the parent page?  */      if(pos >= BTPAGE_LENGTH(bt,p2)) {	/*  Exchange p1 and p3  */	oStack[oDepth - 1].BTP_Position = --pos;	flag = TRUE;      } else {	flag = FALSE;      }      /*  Get right hand side page  */      if(flag && nDepth >= 0 && nStack[nDepth].BTP_PageNr == page2 &&	 pos == nStack[nDepth].BTP_Position)	/*  Special case: While inserting we just split the page left	 *   to us, so the *real* left hand page is subPage instead	 *   of the pointer on the page.	 */	page3 = subPage;      else	/*  Get left (flag==TRUE) or right (flag==FALSE) neighbouring page  */	memcpyl(&page3,p2 + (BTOFF_START(bt) +			     (flag ? BTOFF_SUBPAGEM1(bt) : BTOFF_SUBPAGE(bt))) +		pos * fLen2,sizeof(page3));      /*  Get neighbouring page  */      if((p3 = bayGetPage(bt,page3,BFILEMODE_DIRTY)) == NULL) {	(void)baySetPage(bt,page2,BFILEMODE_UNPROT);	goto error1;      }#ifdef DEBUGD      printf("  Underflow on page2 %d at pos %d flag %s page3 %d\n",	     page2,pos,flag ? "YES" : "NO",page3);#endif      if(flag) { /*  Exchange left and right page  */	long tp = page1; page1 = page3; page3 = tp;	p = p1; p1 = p3; p3 = p;      }      /*  Go to position of element on page2  */      p = p2 + BTOFF_START(bt) + pos * fLen2;      /*  Check if we can lend elements from the neighbouring page, or if       *   we can unite them to yield a new one.       */      len = BTPAGE_LENGTH(bt,p1) + BTPAGE_LENGTH(bt,p3);      if(len >= currMax) {	long newLen,diff;	newLen = len / 2; /*  page1 will have length newLen afterwards  */	/*  Redistribute elements  */	if(BTPAGE_LENGTH(bt,p1) < newLen) {	  diff = newLen - BTPAGE_LENGTH(bt,p1) - 1;	  /*  Move the parent element from page2 and some elements from	   *   page3 to page1. The subpage entry for the single element	   *   from page2 is taken from the leftmost subpage from page3.	   */	  memcpy(p1 + BTOFF_START(bt) + BTOFF_USER(bt) +		 BTPAGE_LENGTH(bt,p1) * fLen,p + BTOFF_USER(bt),BTLEN_USER(bt));	  /*  Need to copy at least leftmost subpage element  */#ifdef CONFIG_BTREE_EXTRALEAF	  if(BTPAGE_ISLEAF(bt,p1))	    memcpy(p1 + BTOFF_START(bt) + (BTPAGE_LENGTH(bt,p1) + 1) * fLen,		   p3 + BTOFF_START(bt),diff * fLen);	  else#endif	    memcpy(p1 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt) +		   (BTPAGE_LENGTH(bt,p1) + 1) * fLen,		   p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt),		   diff * fLen + sizeof(BTreePage));	  /*  Set new element on page2 and move contents of page3  */	  memcpy(p + BTOFF_USER(bt),		 p3 + BTOFF_START(bt) + BTOFF_USER(bt) + diff * fLen,		 BTLEN_USER(bt));#ifdef CONFIG_BTREE_EXTRALEAF	  if(BTPAGE_ISLEAF(bt,p3))	    memmove(p3 + BTOFF_START(bt),p3 + BTOFF_START(bt) +		    (diff + 1) * fLen,(BTPAGE_LENGTH(bt,p3) - diff - 1) * fLen);	  else#endif	    memmove(p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt),		    p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt) +		    (diff + 1) * fLen,(BTPAGE_LENGTH(bt,p3) - diff - 1) *		    fLen + sizeof(BTreePage));	  BTPAGE_LENGTH(bt,p1) += diff + 1;	  BTPAGE_LENGTH(bt,p3) -= diff + 1;	} else if(BTPAGE_LENGTH(bt,p3) < newLen) {	  /*  Move parent element from page2 and some from page1 to page3	   *   The subpage entry for the single element from page2 is	   *   taken from the leftmost subpage from page3.	   */	  diff = newLen - BTPAGE_LENGTH(bt,p3) - 1;#ifdef CONFIG_BTREE_EXTRALEAF	  if(BTPAGE_ISLEAF(bt,p3))	    memmove(p3 + BTOFF_START(bt) + (diff + 1) * fLen,		    p3 + BTOFF_START(bt),BTPAGE_LENGTH(bt,p3) * fLen);	  else#endif	    memmove(p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt) +		    (diff + 1) * fLen,		    p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt),		    BTPAGE_LENGTH(bt,p3) * fLen + sizeof(BTreePage));	  memcpy(p3 + BTOFF_START(bt) + BTOFF_USER(bt) + diff * fLen,		 p + BTOFF_USER(bt),BTLEN_USER(bt));	  /*  Need to copy at least leftmost subpage element  */#ifdef CONFIG_BTREE_EXTRALEAF	  if(BTPAGE_ISLEAF(bt,p1))	    memcpy(p3 + BTOFF_START(bt),p1 + BTOFF_START(bt) +		   (BTPAGE_LENGTH(bt,p1) - diff) * fLen,diff * fLen);	  else#endif	    memcpy(p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt),		   p1 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt) +		   (BTPAGE_LENGTH(bt,p1) - diff) * fLen,		   diff * fLen + sizeof(BTreePage));	  /*  Set new element on page2 and move contents of page3  */	  memcpy(p + BTOFF_USER(bt),		 p1 + BTOFF_START(bt) + BTOFF_USER(bt) +		 (BTPAGE_LENGTH(bt,p1) - diff - 1) * fLen,BTLEN_USER(bt));	  BTPAGE_LENGTH(bt,p1) -= diff + 1;	  BTPAGE_LENGTH(bt,p3) += diff + 1;	}	oDepth = -1; /*  stop deleting  */      } else {	/* **  We can decrease the number of pages  ** */#ifdef DEBUGD	printf("  CONCAT PAGES %d: %d %d , %d\n",page1,	       BTPAGE_LENGTH(bt,p1),BTPAGE_LENGTH(bt,p3),len + 1);#endif	/*	 *  Move single parent element from page2 and all elements	 *   from page3 to page1. The subpage entry for the element	 *   from page2 is taken from the leftmost subpage from page3.	 */	memcpy(p1 + BTOFF_START(bt) + BTOFF_USER(bt) +	       BTPAGE_LENGTH(bt,p1) * fLen,	       p + BTOFF_USER(bt),BTLEN_USER(bt));#ifdef CONFIG_BTREE_EXTRALEAF	if(BTPAGE_ISLEAF(bt,p1))	  memcpy(p1 + BTOFF_START(bt) + (BTPAGE_LENGTH(bt,p1) + 1) * fLen,		 p3 + BTOFF_START(bt),BTPAGE_LENGTH(bt,p3) * fLen);	else#endif	  memcpy(p1 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt) +		 (BTPAGE_LENGTH(bt,p1) + 1) * fLen,		 p3 + BTOFF_START(bt) + BTOFF_SUBPAGEM1(bt),		 BTPAGE_LENGTH(bt,p3) * fLen + sizeof(BTreePage));	/*  Concatenated page now contains all elements.  */	BTPAGE_LENGTH(bt,p1) = len + 1;	/*  Free the neighbouring page and unlock other one  */	if((*(bt->BAT_PageAdmin))(bt,page3) < 0) {	  (void)baySetPage(bt,page2,BFILEMODE_UNPROT);	  if(flag) page1 = page3;	  goto error1;	}	/*  Go to next level  */	oDepth--;      }      /*  Remove all page locks  */      if(baySetPage(bt,flag ? page3 : page1,BFILEMODE_UNPROT) < 0 ||	 baySetPage(bt,page2,BFILEMODE_UNPROT) < 0) goto error;    }  }  /* ****  END MAIN LOOP  **** */  if(oCont) free(oStack);  if(nCont) free(nStack);#ifndef CONFIG_USE_ALLOCA  if(temp) free(temp);#endif  return(0);error1:  /*  Clean up: Unlock page1 before return  */  (void)baySetPage(bt,page1,BFILEMODE_UNPROT);error:#ifndef CONFIG_USE_ALLOCA  free(temp);#endif  return(-1);}