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Trailing-Edge - PDP-10 Archives - bb-h138f-bm - 7-sources/rmsidx.b36
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%TITLE 'I N D E X  -- IDX file routines'
!<BLF/REQUIRE 'RMSBLF.REQ'>
MODULE INDEX (IDENT = '2.0'
		) =
BEGIN
!
!	COPYRIGHT (C) DIGITAL EQUIPMENT CORPORATION 1977, 1986.
!	ALL RIGHTS RESERVED.
!
!	THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY  BE  USED  AND
!	COPIED ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE AND WITH
!	THE INCLUSION OF THE ABOVE COPYRIGHT NOTICE.   THIS  SOFTWARE  OR
!	ANY  OTHER  COPIES  THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE
!	AVAILABLE TO ANY OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF  THE
!	SOFTWARE IS HEREBY TRANSFERRED.
!
!	THE INFORMATION IN THIS SOFTWARE IS  SUBJECT  TO  CHANGE  WITHOUT
!	NOTICE  AND  SHOULD  NOT  BE CONSTRUED AS A COMMITMENT BY DIGITAL
!	EQUIPMENT CORPORATION.
!
!	DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR  RELIABILITY  OF
!	ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY DIGITAL.
!

!++
! FACILITY:	RMS
!
! ABSTRACT:
!
!	This module contains all routine which traverse and modify
!	the index structure of an RMS-36 indexed file.
!
! ENVIRONMENT:	User mode, no interrupts
!
! AUTHOR: S. Blount , CREATION DATE: 27-Oct-1976
!
! MODIFIED BY:
!
!	Ron Lusk, 24-May-82 : VERSION 1
! 01	- (SB) Release bucket if GTBKTPTR fails
! 02	- (SB) Changes for locking
! 03	- (SB) Make INSRTIREC release index bucket if no high-key
! 04	- (SB) Fix bug in SPTINDEX re: loc of split
! 05	- (SB) Don't insert new idx rec if old key same as new hi-key
! 06	- (SB) Add call to ADJIPTR if key of hi-key rec NEQ index key
! 07	- (SB) Fix bug in GTBKTPTR on getting wrong bktsize when going to data
! 08	- (SB) Bug in INSRTIREC if 3-bucket split with NOHIKEY set
! 09	- (SB) Check for FLGHIKEY in SINDEXBKT (SIXBIT keys)
! 10	- (SB) Move HIKEY flag to new rec on INSRTIREC
! 11	- (SB) Fix SINDEXBKT to handle <0 keys
! 12	- (SB) Fix debug error in GTBKTPTR
! 13	- (SB) Add big comment to IDXUPD
! 14	- Make key comparisons work in SINDEXBKT (RMS edit 62)
!	Ron Lusk, 21-Jun-83 : VERSION 2
! 400	- Clean up code some more
! 412	- Fix parameter binding in GTNBKT.
!--

!
! TABLE OF CONTENTS
!
!
!    makeirecord,		- Create an index record
!    getroot,			- Locate, lock, map root bucket
!    sindexbkt,			- Search bucket for key string
!    followpath,		- Follow index to data level
!    fndrec,			- Traverse index to any level
!    idxupdate,			- Update the index structure
!    gtbktptr,			- Get next bucket down in tree
!    gtnbkt,			- Get next bucket in this level
!    sptindex,			- Split an index bucket
!    insrtirecord,		- Insert an index record
!    fnddata;			- Traverse index from root to data
!
! INCLUDE FILES:
!

REQUIRE 'rmsreq';

!
! MACROS:
!
!   None.
!
! EQUATED SYMBOLS:
!
!   None.
!
! OWN STORAGE:
!
!   None.
!
! EXTERNAL REFERENCES:
!
!   None
!
%SBTTL 'MAKEIRECORD -- Create index record'

GLOBAL ROUTINE makeirecord (bucketnumber, recordptr, keyptr) : NOVALUE =

!++
! FUNCTIONAL DESCRIPTION:
!	Create an index record in an indexed file.
!
! FORMAL PARAMETERS
!
!	Bucketnumber -- bucket to put in the index record
!	Recordptr -- address to write record
!	Keyptr -- address of key string to go in index record
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	NONE.
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

    MAP
	recordptr : REF BLOCK,
	keyptr : REF BLOCK;

    TRACE ('MAKEIRECORD');
    checkinput (bucketnumber, GTR, 0);
    !
    !   Store flags and bucket number
    !
    recordptr [irflags] = defirflags;		! Use the default
    recordptr [irbucket] = .bucketnumber;
    !
    !   Now, move the string
    !
    recordptr = .recordptr + irhdrsize;
    movewords (.keyptr, 			! From
	.recordptr, 				! To
	.kdb [kdbkszw]);			! Size
    RETURN
    END;					!End of MAKEIRECORD
%SBTTL 'GETROOT -- get root of index'

GLOBAL ROUTINE getroot (recdesc, bktdesc) =

!++
! FUNCTIONAL DESCRIPTION:
!	Routine to get the root of an index structure.  GETROOT
!	is responsible for locating and mapping the current root
!	of the index.  If there is not a current root, then the
!	file prologue must be read to find the new root.
!
! FORMAL PARAMETERS
!
!	RECDESC -- address of record descriptor packet
!	BKTDESC -- address of bucket descriptor packet
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! COMPLETION CODES:
!
!	TRUE -- root found.
!	FALSE -- error (error code in USRSTS): BUSY, NO FREE CORE AVAILABLE
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

    MAP
	bktdesc : REF BLOCK,
	recdesc : REF BLOCK;

    LOCAL
	idbptr : REF BLOCK,			! Ptr to index descriptor
	plogbktdesc : BLOCK [bdsize],		! Bucket desc for file prologue
	lockfunction,				! Function code for ENQ/DEQ
	loopcount,				! Keep track of out progress
	bucketsize,				! Size of root bucket
	rootbucket;				! Root bucket number

    REGISTER
	rootpointer : REF BLOCK;		! Ptr to root bucket

    LITERAL
	maxloops = 1;				! Max # of times we will loop

    TRACE ('GETROOT');
    loopcount = 0;				! Clear our loop counter
    bucketsize = .kdb [kdbibkz];		! Get bucket size

    !+
    !   Here is the big loop. This loop is executed more
    !   than once only if there is a root in the KDB
    !-

    repeat

    						! Indefinitely
	BEGIN

	IF .loopcount GTR maxloops THEN rmsbug (msgloop);

	!
	!   Get the current bucket number
	!
	rootbucket = .kdb [kdbroot];

	IF .rootbucket NEQ 0
	THEN

	!+
	!	There must be an index for this key
	!-

	    BEGIN

	    IF getbkt (.rootbucket, 		! Bucket
		    .bucketsize, 		! Bucketsize
		    false, 			! Lock
		    .bktdesc			! Descriptor
		) EQL false
	    THEN
		RETURN false;

	    rootpointer = .bktdesc [bkdbktadr];	! Get address

	    IF chkflag (rootpointer [bhflags], bhflgroot) NEQ 0	!
	    THEN
		RETURN true;			! This is the root

	    !
	    !   This bucket is no longer the root
	    !
	    rmsbug (msgrchanged)
	    END;				! Of if rootbucket isnt zero

	!
	!   We must read the index descriptor in the file
	!   prologue
	!

	IF (idbptr = getidb (plogbktdesc)) EQL false	!
	THEN
	    RETURN false;

	!
	!   Get the new root bucket number
	!
	kdb [kdbroot] = .idbptr [idbroot];
	!
	!   Return the prologue bucket
	!
	putbkt (false, 				! No update
	    plogbktdesc);			! Bucket
	!
	!   Now, check if there is a root yet for this index.
	!   There will be a valid root except where a file was
	!   "$CREATED" without any records, and then the file
	!   was opened for input.
	!

	IF .kdb [kdbroot] EQL 0
	THEN
	! There is no root
	    BEGIN

	    IF seqadr				!
	    THEN
		usrsts = er$eof			! We should return EOF
	    ELSE
		usrsts = er$rnf;		! We should return RNF

	    					! (record not found)
	    RETURN false
	    END					! Of if there is no root
	ELSE
	    clrflag (kdb [kdbflags], flgnoindex);

	!
	!   Bump our loop counter and go back and try again
	!
	loopcount = .loopcount + 1
	END;					! Of repeat loop

    rmsbug (msgcantgethere);			! Can never execute this
    RETURN false;
    END;					!End of GETROOT
%SBTTL 'SINDEXBKT -- search index bucket'

GLOBAL ROUTINE sindexbkt (recdesc, bktdesc) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	Routine to search a mapped, locked index bucket for
!	a key string.  SINDEXBKT searches an index bucket for
!	the index record which is greater than or equal to a
!	specified user search key.  Both strings must be
!	non-segmented.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    USERPTR -- address of search key string ( K(S) )
!	    USERSIZE -- size of search key string
!	    RECPTR -- address to begin search
!		EQL ZERO ==> Start at top of bucket
!		GTR ZERO ==> Address to start at
!		LSS ZERO ==> Search only first record
!	    RECPTR is modified to point to record terminating search
!	    LASTRECPTR -- modified to point at previous record
! 	BKTDESC -- bucket descriptor packet
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- search terminated normally (search key is LEQ index record)
!		FLGLSS may be set (in recdesc) if K(S) < record key
!	FALSE -- Key string not found
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	bktdesc : REF BLOCK;

    REGISTER
	tempac,
	tempac1,
	tempac2;

    LOCAL
	endptr : REF BLOCK,			! End of bucket pointer
	recordtocheck : REF BLOCK,		! Pointer for bucket scan
	interval,				! 1/2 # rec's left to scan
	bktptr : REF BLOCK,			! Pointer to top of bucket
	firstrecord,				! Address of first record
	words,					! Words to compare for key
	slackbytes,				! Left-over bytes
	bytesperword,				! # of bytes in each word
	keybsz,					! Byte size of key
	sizeofrecord,				! Total size of each record
	addr1,					! Address of given key
	addr2,					! Addr of key to compare against
	comparesult,				! Result of last compare
	lastlessorequal,			! Outcome of last LEQ compare
	count,					! Keeps track of key compare
	temp1,					! Temps used for string compare
	temp2,
	temp5;

    TRACE ('SINDEXBKT');
    !
    !   Clear the LSS flag in the record descriptor
    !
    clrflag (recdesc [rdstatus], rdflglss);
    !
    !   Set up the end-of-bucket pointer
    !
    bktptr = .bktdesc [bkdbktadr];
    endptr = .bktptr + .bktptr [bhnextbyte];
    !
    !   Check a few things
    !

    IF (.bktptr [bhthisarea] NEQ .kdb [kdbian]) OR 	!
	(.bktptr [bhbtype] NEQ btypeindex)	! Check bucket header
    THEN
	BEGIN
	fileproblem (fe$bhe);			! Bad bucket header
	usrret ()
	END;

    !
    !   Make sure bucket isn't empty
    !

    IF .bktptr [bhnextbyte] EQL bhhdrsize
    THEN
    ! No records in this bucket
	BEGIN
	fileproblem (fe$bem);			! Empty bucket found
	usrret ()
	END;

    !
    !   Compute total size of an index record
    !
    sizeofrecord = .kdb [kdbkszw] + irhdrsize;
    !
    !   Get byte size for later
    !
    keybsz = .kdb [kdbkbsz];
    !
    !   Adjust start and end of search space
    !

    IF (firstrecord = .recdesc [rdrecptr]) LEQ 0
    THEN
    ! Start from first record in bucket
	BEGIN

	IF .firstrecord LSS 0
	THEN
	! Pretend end of bucket is after first record
	    endptr = .bktptr + bhhdrsize + .sizeofrecord;

	firstrecord = .bktptr + bhhdrsize
	END
    ELSE
    ! Make sure start address is in bucket
	BEGIN
	!   Check start address

	IF .firstrecord GEQ .endptr THEN rmsbug (msginput);

	END;

    !
    !   Set up first interval and initial record to check
    !
    interval = (.endptr - .firstrecord)/(2*.sizeofrecord);
    recordtocheck = .interval*.sizeofrecord + .firstrecord;
    !
    !   Set up for key compare
    !
    bytesperword = 36/.keybsz;
    words = .recdesc [rdusersize]/.bytesperword;
    slackbytes = (.recdesc [rdusersize] MOD .bytesperword);
    !
    !   Get address of key we're looking for
    !
    addr1 = .recdesc [rduserptr];

    !+
    !   Main loop
    !-

    repeat

	BEGIN
	!
	!   Compare strings
	!
	!
	!   This is the key we're checking against this time
	!
	addr2 = .recordtocheck + irhdrsize;
	lookat ('	RECORD PROBE AT: ', recordtocheck);

	!+
	!   Compare the entire index key. We will do this
	!   by comparing each word as a unit (ignoring extra
	!   bits in the word), and then compare the slack bytes.
	!-

	tempac = false;				! Assume no full words

	IF .words GTR 0
	THEN

	!+
	!   We must compare the whole words.  TEMPAC will be set to
	!   true if a difference in the keys can be determined
	!   without checking the slack bytes.
	!-

	    BEGIN
	    comparesult = 1;			! Assume our key is GTR
	    temp2 = POINT (.recdesc [rduserptr], 36, .bytesperword*.keybsz);
	    temp5 = .temp2;
	    temp5<rh> = .addr2;			! Form destination address
	    !
	    !   Compare the whole words in the key
	    !

	    IF cstringle (temp2, 		! Search key
		    temp5, 			! Index key
		    words, 			! Size
		    words			! Size
		) EQL false
		!
		!   If this failed, then our search key is GTR
		!   than the index record key.
		!
	    THEN
		tempac = true			! Exit from loop
	    ELSE

	    !+
	    !   Our key is LEQ the index key
	    !-

		BEGIN
		ldb (tempac1, temp2);		! Get the bytes
		ldb (tempac2, temp5);
		comparesult = -1;		! Assume LSS
		tempac = (IF .tempac1		! Search key
		    LSSU .tempac2		! Index key	!M62
		THEN true ELSE false)
		END;

	    END;

	!
	!   Now, compare the slack bytes if there are any,
	!   and if the word comparison was equal up to this point
	!

	IF .tempac EQL false
	THEN
	! We must compare the slack bytes
	    BEGIN
	    temp1 = POINT (.recdesc [rduserptr] + .words, 36, .slackbytes*.keybsz);
	    temp2 = (.addr2 + .words);
	    temp2<lh> = .temp1<lh>;
	    !
	    !   Load the last series of bytes as a single byte
	    !
	    tempac1 = scani (temp1);
	    tempac2 = scani (temp2);

	    IF .tempac1 LSSU .tempac2		!M62
	    THEN
		comparesult = -1
	    ELSE
		BEGIN
		!
		!   Our slack bytes were GEQ index bytes
		!
		comparesult = (IF .tempac1 EQL .tempac2	!
		THEN 0				! Equal
		ELSE 1)				! Our key is GTR
		END

	    END;				! Of compare the slack bytes

	!
	!   Was our key greater than this one?
	!

	IF .comparesult GTR 0
	THEN
	! Try second half of search space
	    BEGIN
	    ! Our key is greater
	    rtrace (%STRING ('	RECORD PROBE EQL TOO LOW...', 	!
		    %CHAR (13), %CHAR (10)));

	    IF .recordtocheck GEQ (.endptr - .sizeofrecord)
	    THEN
	    ! Key isn't in bucket
		BEGIN
		! Bad return
		recdesc [rdlastrecptr] = .recordtocheck;
		recdesc [rdrecptr] = .endptr;
		RETURN false
		END
	    ELSE
		BEGIN
		! Update

		IF .interval EQL 0
		THEN
		! Next one must be right
		    BEGIN
		    recdesc [rdlastrecptr] = .recordtocheck;
		    recdesc [rdrecptr] = .recordtocheck + .sizeofrecord;

		    IF .lastlessorequal LSS 0 THEN setlssflag (recdesc);

		    RETURN true
		    END
		ELSE
		! We aren't finished yet
		    BEGIN
		    ! Adjust record and interval
		    recordtocheck = 		!
		    .recordtocheck + ((.interval + 1)/2)*.sizeofrecord;
		    interval = .interval/2
		    END

		END

	    END
	ELSE
	! Our key was less than or equal, which?
	    BEGIN
	    ! Less than or equal
	    lastlessorequal = .comparesult;	! Remember for later

	    IF .interval NEQ 0
	    THEN
	    ! We aren't through yet
		BEGIN
		! Adjust record and interval
		recordtocheck = .recordtocheck - ((.interval + 1)/2)*.sizeofrecord;
		interval = .interval/2
		END
	    ELSE
	    ! Interval is 0
		BEGIN
		! Success with < or =

		IF .recordtocheck EQL .firstrecord
		THEN
		    recdesc [rdlastrecptr] = .recordtocheck
		ELSE
		    recdesc [rdlastrecptr] = .recordtocheck - .sizeofrecord;

		recdesc [rdrecptr] = .recordtocheck;

		IF .comparesult LSS 0		!
		THEN
		    setlssflag (recdesc)	!
		ELSE
		    clrflag (recdesc [rdstatus], rdflglss);	!

		RETURN true
		END

	    END;

	END

    END;					!End of SINDEXBKT
%SBTTL 'FOLLOWPATH -- follow index path'

GLOBAL ROUTINE followpath (recdesc, databd) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	FOLLOWPATH follows the index path from a particular
!	starting bucket down to a specified level in the index
!	structure.  In general, it will be called with the starting
!	bucket being the root and will search the index and stop
!	at the data bucket.  This routine is called only from $PUT.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    USERPTR -- address of search key
!	    USERSIZE -- size of search key
!	    RECPTR -- modified to address of data record position
!	    LASTRECPTR -- modified to addr of prev record (if any)
!	DATABD -- bucket descriptor of data level bucket
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- Record position located
!	FALSE -- Error, or Record Not Found
!
! SIDE EFFECTS:
!
!	Unknown.
!
! NOTES:
!
!	This routine attempts to recover the correct index
!	structure when a system crash causes an "inefficient
!	tree". This means that the key value in the index record
!	does not reflect the highest key in the data bucket.
!	In such a case, any attempt to locate a key which is
!	between the highest actual key in the data bucket and
!	what the index record key value is, must search the next
!	bucket in the data bucket chain.  Therefore, as this
!	routine searches down the index, it modifies the key
!	in the index record to reflect the correct value.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	databd : REF BLOCK;

    LOCAL
	indexbd : BLOCK [bdsize],		! Index bucket descriptor
	temp;

    REGISTER
	tempac;

    TRACE ('FOLLOWPATH');
    !
    !   Fetch the root
    !

    IF getroot (.recdesc, indexbd) EQL false THEN RETURN false;

    !+
    !   Do this loop until we reach the data level
    !-

    repeat

	BEGIN
	!
	!   Follow the path to level 0
	!
	recdesc [rdlevel] = datalevel;
	recdesc [rdrecptr] = 0;			! Start at top

	IF fndrec (.recdesc, indexbd, .databd) EQL false
	    !
	    !   Did we get down to the data?
	    !
	THEN
	    RETURN false;

	!
	!   If we are data level, we can exit
	!

	IF .recdesc [rdlastlevel] EQL datalevel THEN RETURN true;

	IF (emptyflag (recdesc) NEQ 0)
	THEN
	! We have a bad file
	    BEGIN
	    fileproblem (fe$bem);		! Empty bucket
	    usrret ()
	    END;

	!
	!   At this point, we are past the last
	!   entry, update R(LAST) with K(S). This
	!   situation could have been caused by a
	!   record insertion which aborted (crash,...)
	!   before the index was completely updated.
	!   RMS-36 can then notice this condition and
	!   correct it, as it is doing now.
	!
	movewords (.recdesc [rduserptr], 	! From
	    .recdesc [rdlastrecptr] + irhdrsize, 	! To
	    .kdb [kdbkszw]);			! Size
	!
	!   At this point, we updated the index
	!   key part way down the tree.
	!
	rtrace (%STRING ('	RESTARTING FPATH...', 	!
		%CHAR (13), %CHAR (10)))
	END;

    rmsbug (msgcantgethere);
    RETURN false;
    END;					! End of FOLLOWPATH
%SBTTL 'FNDREC -- locate data record'

GLOBAL ROUTINE fndrec (recdesc, startbd, endbd) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	FNDREC locates a data record (UDR/SIDR) by searching the index
!	structure.  This routine begins its search at an arbitrary
!	bucket in the index and searches downward until it reaches the
!	desired level in the tree.  If a bucket is found with
!	K(LAST) < K(S), then we know that there may have been a crash and
!	the index didn't get updated fully.  In such a case, the next
!	bucket in the chain is searched to see if K(0) in the new bucket
!	is > K(S).  If so, we continue the operation with the current
!	bucket.  If K(0) < K(S), we must continue the search at the top
!	of the next bucket.
!
!	Whether we continue the search in the next bucket is determined
!	by the HORIZOK bit in the record descriptor flag field.  This
!	bit is set on a $FIND/$GET and clear on a $PUT.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    USERPTR -- address of search key string
!	    USERSIZE -- size of search key string
!	    RECPTR -- address to start search (0 = top of bucket)
!		    Modified to address of record terminating search.
!	    FLAGS -- flag bits
!		HORIZOK -- horizontal search is OK
!		PASTLAST -- may be set, even on successful exit
!	    LASTRECPTR -- Modified to point to record before that one
!		    which terminated search.
!	    LASTLEVEL -- modified to last level searched.
!	STARTBD -- bucket descriptor of starting bucket
!	ENDBD -- bucket descriptor of ending bucket (returned)
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- search terminated normally
!	FALSE -- error, data bucket is busy (busy flag set)
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	startbd : REF BLOCK,
	endbd : REF BLOCK;

    LABEL
	iteration;

    LOCAL
	bktno,					! Bucket to read during
						! horizontal scan --
						!   -1: K(S) > K(0)
						!   0: Last bucket in chain
						!  +n: Look here for K(0)
	currentbktptr : REF BLOCK,		! Current bucket top
	currentlevel,				!
	nbp : REF BLOCK,			! Next bucket in chain
	nextbd : BLOCK [bdsize],		! Next bucket
	currentbucket,				! This bucket number
	saverecptr,				! Temp storage
	savelastrecptr,				! ...
	savestatus,				! ...
	targetlevel;				! Input level number

    TRACE ('FNDREC');
    !
    !   For now, we always want to go to the data level
    !
    checkinput (recdesc [rdlevel], EQL, datalevel);
    !
    !   Make sure we do a key search
    !
    recdesc [rdrfa] = 0;
    targetlevel = .recdesc [rdlevel];		! Get level #
    !
    !   Set up some pointers
    !
    currentbktptr = .startbd [bkdbktadr];
    !
    !   Make the input bucket the current bucket
    !
    movebktdesc (startbd, 			! From
	endbd);					! To

    !+
    !   This is the big loop. It is executed once for each
    !   level of the index that it searches.
    !-

    repeat

iteration :
	BEGIN
	!
	!   Get level of current bucket
	!
	currentbktptr = .endbd [bkdbktadr];
	currentlevel = .currentbktptr [bhlevel];
	!
	!   Store this value in the record desc
	!
	recdesc [rdlastlevel] = .currentlevel;
	!
	!   Store this bucket number in the path array
	!
	currentbucket = .endbd [bkdbktno];
	path [.currentlevel, pathbkt] = .currentbucket;
	lookat ('	PREPARING TO SEARCH BKT: ', currentbucket);
	lookat ('	AT LEVEL: ', currentlevel);
	!
	!   We now must search the current bucket
	!

	IF (IF .currentlevel EQL datalevel	!
	    THEN 				! We should use the data bucket ROUTINE
		sdatabkt (.recdesc, 		! Record descriptor
		    .endbd)			! Bucket
	    ELSE
	    ! We should use the index bucket routine
		sindexbkt (.recdesc, 		! Record descriptor
		    .endbd)			! Bucket
	    ) EQL false
	    !
	    !   What happened?
	    !
	THEN
	    BEGIN
	    !
	    !   We did not find the record. The following
	    !   could be the cause:
	    !
	    !   1. K(LAST) < K(S)
	    !
	    !
	    rtrace (%STRING ('	BUCKET SEARCH FAILED...', 	!
		    %CHAR (13), %CHAR (10)));
	    !
	    !   First, save the output of the search
	    !
	    saverecptr = .recdesc [rdrecptr];
	    savelastrecptr = .recdesc [rdlastrecptr];
	    savestatus = .recdesc [rdstatus];
	    !
	    !   Fetch the next bucket in the chain
	    !
	    !
	    !   If GTNBKT returns false, then there was no
	    !   next bucket...this situation is perfectly OK
	    !

	    IF gtnbkt (.endbd, 			! Current
		    nextbd, 			! Next
		    false			! No lock
		) EQL false
	    THEN
		RETURN true;

	    !
	    !   We have now gotten the next bucket
	    !   in the chain. We must check the first
	    !   record to see if we should continue the
	    !   search or stay with the current record.
	    !   If HORIZOKFLAG, then the search continues regardless
	    !   of whether K(S) > K(0). If it's off,
	    !   implying insert mode, continue
	    !   the search only if insert point beyond K(0).
	    !

	    IF horizokflag (recdesc) EQL 0
	    THEN
		repeat

		    BEGIN
		    ! compare K(S) with K(0) in the next bucket
		    recdesc [rdrecptr] = -1;	! Flag 1 rec search

		    IF .currentlevel EQL datalevel
		    THEN
			BEGIN
			recdesc [rdrfa] = 0;	! Key search
			sdatabkt (.recdesc, nextbd)
			END
		    ELSE
		    !  This is an index bucket
			sindexbkt (.recdesc, nextbd);

		    !
		    !	Is K(S) < K(0)? First, determine if key is
		    !	there;  if not there, also check if EOF
		    !
		    bktno = -1;			! Presume valid entry seen

		    IF pastlastflag (recdesc) NEQ 0	! Any key in bucket
		    THEN
			BEGIN			! No
			nbp = .nextbd [bkdbktadr];	! Pt at bkt last read

			IF chkflag (nbp [bhflags], bhflgend) EQL 0
			THEN
			    bktno = .nbp [bhnextbkt]	! Set bkt to read
			ELSE
			    bktno = 0;		! EOF

			END;

		    IF lssflag (recdesc) NEQ 0 OR .bktno EQL 0
		    THEN

		    !+
		    !	Insertion point found by key comparison
		    !	or EOF, and we should release the next
		    !	bucket and use the old one.
		    !-

			BEGIN			!
						!   Yes
						!
			rtrace (%STRING ('	K(S)<K(0)', %CHAR (13), %CHAR (10)));
			putbkt (false, 		! No update
			    nextbd);		! Bkt
			!
			!   Restore our search keys
			!
			recdesc [rdrecptr] = .saverecptr;
			path [.currentlevel, pathoffset] = 	!
			.saverecptr - .currentbktptr;
			recdesc [rdlastrecptr] = .savelastrecptr;
			recdesc [rdstatus] = .savestatus;
			setpastlastflag (recdesc);
			RETURN true;
			END;			! of if K(S) < K(0)

		    IF .bktno LSS 0 THEN EXITLOOP;	!K(S)>=K(0)

		    ! No keys in bkt chained to, pick up next 1
		    putbkt (false, 		! No update
			nextbd);		! Bkt

		    IF getbkt (.bktno, 		! Bucket to read
			    .kdb [kdbdbkz], 	! Always data bucket
			    false, nextbd) EQL false
		    THEN
			RETURN false;

		    END;

	    !
	    !   No...K(S) >= K(0) or HORIZONTAL-OK flag
	    !   was on.  We should restart
	    !   the search at the top of next buckeT
	    !
	    recdesc [rdrecptr] = 0;		! Start at top
	    putbkt (false, 			! No update
		.endbd);			! Bucket
	    !
	    !   Make the next bucket the current one
	    !
	    movebktdesc (nextbd, 		! From
		endbd);				! To
	    !
	    !   Exit from the loop and start at top again
	    !
	    LEAVE iteration
	    END;

	!
	!   We have found a record with key >= K(S).
	!
	rtrace (%STRING ('	FOUND TARGET RECORD', %CHAR (13), %CHAR (10)));
	!
	!   Store the offset into the current bucket in the path array
	!
	path [.currentlevel, pathoffset] = .recdesc [rdrecptr] - .currentbktptr;
	!
	!   Is this the level we wanted?
	!

	IF .currentlevel EQL .targetlevel THEN RETURN true;

%IF dbug
%THEN

	IF .currentlevel LSS .targetlevel THEN rmsbug (msglevel);

%FI

	!
	!   Get the bucket at the next level in the tree
	!
	savestatus = gtbktptr (.recdesc, 	! Record descriptor
	    .endbd, 				! Current bucket
	    nextbd);				! Next bucket
	!
	!   We can now release the current bucket
	!
	putbkt (false, 				! No update
	    .endbd);				! Bucket
	!
	!   If we couldn't get the next bucket, then exit
	!

	IF .savestatus EQL false THEN RETURN false;

	!
	!   Make sure we start at top of bucket
	!
	recdesc [rdrecptr] = 0;
	!
	!   Make the next bucket to be the current one
	!
	movebktdesc (nextbd, 			! From
	    endbd);				! To
	END;

    rmsbug (msgcantgethere);
    RETURN false;
    END;					! End of FNDREC
%SBTTL 'IDXUPDATE -- modify index in split'

GLOBAL ROUTINE idxupdate (recdesc, databd, splitbd1, splitbd2) =

!++
! FUNCTIONAL DESCRIPTION:
!
!   This routine is responsible for all index modifications which
!   must be done when a new data record insertion causes the data
!   bucket to split.  This routine iteratively traces up the tree;
!   then, it inserts or modifies the index records to reflect the
!   split at the next lower level.  If this index record insertion
!   also causes a bucket split, the procedure is repeated up until
!   (potentially) a new root is generated.  The data bucket is not
!   unlocked in this routine.
!
!   Terminology used in IDXUPDATE:
!	R(NEW)  -- The new inserted data record
!	R(LOW)  -- Set of records with keys < R(NEW)
!	R(HIGH) -- Set of records with keys > R(NEW)
!	K(HIGH) -- New high key for original bucket which split
!
! FORMAL PARAMETERS
!
!   RECDESC -- record descriptor
!	LASTRECPTR -- points to last data record (K(HIGH)) of original bucket
!	USERPTR -- pointer to user key string
!	USERSIZE -- full key string size
!   DATABD -- bucket descriptor of original data bucket
!   SPLITBD1 -- bucket descriptor of split-bucket (contains R(HIGH))
!   SPLITBD2 -- bucket descriptor of second split-bucket (if 3-way split)
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!   TRUE -- OK
!   FALSE -- error, no pages left for split of index
!
! SIDE EFFECTS:
!
!	Unknown
!
! NOTES:
!
!	1.	See the notes under "INSRTIRECORD" for a discussion
!		of the placement of the new high-key value for
!		a bucket split.
!
!	2.	Note that the bucket which contains R-HIGH (SPLITBD1)
!		has already been released when this routine is entered.
!		Thus, only the bucket number is used from the bucket
!		descriptor...the actual bucket itself must not be
!		accessed in any way.
!
!	3.	There are three conditions which may arise when the index
!		record is checked in this routine:
!
!		a) the search key (of new record) is LSS the key of the
!			index record. this is by far the usual case.
!		b) the search key is EQL to index key. This is caused by
!			a split of a bucket with a lot of a single dup key.
!			Thus, the old bucket still has a dup for the hi-key
!			and the new bucket contains only the same dup keys.
!		b) the search key is GTR the index key. this is very
!			unusual and is caused when the bucket which is being
!			split is not the same data bucket found when the search
!			terminated at the data level (e.g., a series of dups
!			had to be passed to get to the insertion point).
!			In this case, we really need to be at the index record
!			which reflect the new hi-key value of the split bucket.
!			Thus, we will call ADJIPTR to find the new index record.
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	databd : REF BLOCK,
	splitbd1 : REF BLOCK,
	splitbd2 : REF BLOCK;

    LOCAL
	indexbd : BLOCK [bdsize],		! Root bucket descriptor
	arrayindex,				! Used to index into path
	nextindexbucket,			! Next bucket to get
	indexbucketsize,
	originalbd : BLOCK [bdsize],
	irecordptr : REF BLOCK,			! Ptr to current index record
	saveduserptr,				! Temp storage for search key
	bktonnextlevel;

    TRACE ('IDXUPDATE');
    !
    !   Move the bucket descriptor so it won't get clobbered
    !
    movebktdesc (databd, 			! From
	originalbd);				! To
    indexbucketsize = .kdb [kdbibkz];		! Save time later

    !+
    !   We are currently positioned at level 1 of the index.
    !   We will continue to insert index records until either
    !   we reach the root of no index bucket splitting occurs.
    !
    !   We have the following values:
    !
    !   1.	ORIGINALBD	bucket which was split
    !   2.	SPLITBD1	bucket which contains R(HIGH)
    !   3.	SPLITBD2	bucket which contains R(NEW)
    !                (Only if data is splitting and was 3-bucket split)
    !   4.	INDEXBD		index bucket which will contain
    !                               the new record
    !
    !
    !-

    !

    !   Start at level 1
    !
    arrayindex = seqsetlevel;

    !+
    !   This is the main index update loop
    !-

    UNTIL idxupdateflag (recdesc) EQL 0 DO
	BEGIN
	!
	!   Get the bucket directly above us
	!
	bktonnextlevel = .path [.arrayindex, pathbkt];

	!+
	!   Locate the bucket
	!-

	IF getbkt (.bktonnextlevel, 		! Bucket #
		.indexbucketsize, 		! Size
		false, 				! No lock
		indexbd				! Bucket
	    ) EQL false
	    !
	    !   Did we get it?
	    !
	THEN
	    RETURN false;

	!+
	!   At this point, we have mapped in the next higher
	!   bucket in the index structure. We can now compute the
	!   address of the index entry which got us to the
	!   current level because we have the bucket offset
	!   stored in the path array.
	!-

	irecordptr = (recdesc [rdrecptr] = .path [.arrayindex, pathoffset] + .indexbd [bkdbktadr]);

	!+
	!   We now must determine if we should, in fact, actually
	!   insert a new index record. We don't want to do this if
	!   the old index key is the same as the new high-key value
	!   in the bucket which split. Such a case could be caused
	!   by a series of dups which got moved to a new bucket.
	!-

	saveduserptr = .recdesc [rduserptr];	! Save key ptr
	recdesc [rduserptr] = .rst [rstkeybuff] + (.fst [fstkbfsize]/2);
	irecordptr = .irecordptr + irhdrsize;	! Bump pointer to index key
	!
	!   Compare the index key to the new high key
	!

	IF ckeykk (.recdesc, 			! New high key
		.irecordptr			! Index key
	    ) EQL false
	    !
	    !   If we fail, it means there was a key in the bucket
	    !   which was gtr than the index key. This is caused by
	    !   a split in a data bucket which was not the first bucket
	    !   searched when the record position was initially located.
	    !

	    !++
	    !   ***** NOTE *****
	    !   This entire operation of comparing the key of the
	    !   old index record to the new hi-key of the data bucket
	    !   which was split is necessary if bucket splits can be
	    !   anywhere in the bucket, regardless of whether there
	    !   are duplicates present or not. However, the bucket
	    !   split algorithm currrently (MAY, 1977) divides the
	    !   bucket either before or after the inserted record if
	    !   duplicates are allowed (primary only). Thus, it is
	    !   impossible for a bucket to be split if that bucket is
	    !   <<<not>>> the bucket where the index search terminated
	    !   (i.e., it is not in a list of buckets which are not
	    !   contained in the index). Therefore, this next check
	    !   will never be executed. The code is left in for
	    !   reliability and documentation.
	    !--

	THEN
	    adjiptr (.recdesc, indexbd)
	ELSE
	! The hi-key is .leq. the index key
	    BEGIN
	    !
	    !   If the less-than flag is on, we are ok
	    !

	    IF lssflag (recdesc) EQL 0
	    THEN
		BEGIN
		putbkt (false, 			! No
		    indexbd);			! Bucket
		RETURN true
		END

	    END;

	recdesc [rduserptr] = .saveduserptr;	! Restore ptr

	!+
	!   At this point, RECPTR points to the place to insert
	!   the new index record. We will insert it and
	!   INSERTIRECORD will return updated bucket descriptors
	!   if a further index update is needed.
	!-

	IF insrtirecord (.recdesc, 		! Record descriptor
		indexbd, 			! Bucket
		originalbd, 			! Old bucket
		.splitbd1, 			! Split
		.splitbd2			! Split
	    ) EQL false
	    !
	    !   What happened?
	    !
	THEN
	    RETURN false;

	!
	!   Bump the level number that we are at
	!
	arrayindex = .arrayindex + 1;
	END;

    !
    !   At this point, we have done all our updating
    !
    RETURN true
    END;					! End of IDXUPDATE
%SBTTL 'GTBKTPTR -- get next bucket down'

GLOBAL ROUTINE gtbktptr (recdesc, thisbd, nextbd) =

!++
! FUNCTIONAL DESCRIPTION:
!
!       GTBKTPTR gets the next bucket downward in th index.  It assumes
!       that we are positioned at the current index record, fetches the
!       bucket number of the next bucket in the index and maps it in.
!
! FORMAL PARAMETERS
!
!       RECDESC -- record descriptor
!           RECPTR -- address of index record
!       THISBD -- bucket descriptor of current bucket
!       NEXTBD -- bucket descriptor of next bucket (returned)
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!       TRUE -- bucket found and mapped
!       FALSE -- error, no more memory
!
! SIDE EFFECTS:
!
!	Unknown.
!
!
! NOTES:
!
!	This routine will never lock any buckets, either
!	index or data.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	thisbd : REF BLOCK,
	nextbd : REF BLOCK;

    REGISTER
	acptr : REF BLOCK;

    LOCAL
	nextbucket,				! Next bucket in the index
	lockflag,				! Tells if we will lock it
	bucketsize;

    TRACE ('GTBKTPTR');
    !
    !   Find out the bucket number we need to get
    !
    acptr = .recdesc [rdrecptr];
    nextbucket = .acptr [irbucket];
    !
    !   Find out the level of this bucket
    !
    acptr = .thisbd [bkdbktadr];
    bucketsize = .kdb [kdbibkz];		! Assume index
    lockflag = false;				! Same

    IF .acptr [bhlevel] EQL seqsetlevel
    THEN
    ! We are going to data level
	bucketsize = .kdb [kdbdbkz];

    !
    !   Get the bucket and return
    !
    RETURN getbkt (.nextbucket, 		! Number
	    .bucketsize, 			! Size
	    .lockflag, 				! Lock
	    .nextbd);				! Desc
    END;					! End of GTBKTPTR
%SBTTL 'GTNBKT -- get next bucket in chain'

GLOBAL ROUTINE gtnbkt (thisbd, nextbd, lockflag) =	!		!M412

!++
! FUNCTIONAL DESCRIPTION:
!
!	GTNBKT fetches the next bucket in the horizontal chain of
!	the current level of the index structure.  If there is
!	a next bucket, this routine will map and, if it is a
!	data bucket, will lock it.  If there is no next bucket,
!	GTNBKT returns with an error condition.
!
! FORMAL PARAMETERS
!
!	THISBD -- bucket descriptor of current bucket
!	NEXTBD -- bucket descriptor of next bucket (returned)
!	LOCKFLAG -- flag to determine if we should lock next bucket
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- OK
!	FALSE -- error
!		 bucket was busy (busy flag will be set)
!		 no next bucket
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

!   BIND					! Delete binding	!D412
!	lockflag = .p_lockflag;			! ...			!D412

    MAP
	thisbd : REF BLOCK,
	nextbd : REF BLOCK;

    LOCAL
	thisbktptr : REF BLOCK,			! Bucket pointer
	savedstatus,				! Results of GETBKT here
	nextbucket,				! Number of next bucket
	bucketsize;				! Size of next bucket

    TRACE ('GTNBKT');
    !
    !   Get a pointer to the current bucket
    !
    thisbktptr = .thisbd [bkdbktadr];
    !
    !   Is this the end of the bucket chain?
    !

    IF chkflag (thisbktptr [bhflags], bhflgend) NEQ 0	!
    THEN
    ! This is the end
	RETURN false;

    !
    !   There is another bucket in the chain...find it
    !
    nextbucket = .thisbktptr [bhnextbkt];
    bucketsize = .kdb [kdbibkz];		! Same

    IF .thisbktptr [bhbtype] EQL btypedata THEN bucketsize = .kdb [kdbdbkz];

    !
    !   Map (and lock) the bucket
    !
    RETURN getbkt (.nextbucket, 		! Bucket
	    .bucketsize, 			! Size
	    .lockflag, 				! Lock
	    .nextbd);				! Next-bucket descriptor
    END;					! End of GTNBKT
%SBTTL 'SPTINDEX -- split index bucket'

GLOBAL ROUTINE sptindex (recdesc, indexbd, newindexbd) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	SPTINDEX splits an index bucket during a record insertion.
!	This routine takes the current index bucket and splits
!	the records in it into two groups.  One group of records
!	is moved to a new bucket;  the other group remains in
!	this bucket.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    RECPTR -- address in index bucket to insert record;
!		    modified to point to address to insert new records
!	    LENGTH -- amount of space required for new index records
!	    LASTRECPTR -- address of last record in index bucket which split
!	INDEXBD -- bucket descriptor of index bucket to be split.
!	NEXINDEXBD -- bucket descriptor of new index bucket (returned)
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- OK
!	FALSE - Error
!		No more buckets
!
! SIDE EFFECTS:
!
!	Unknown.
!
! NOTES:
!
!   1.	This routine only splits the index bucket.  It does not leave
!	room for the index record, nor does it adjust the next byte
!	pointer of the bucket to account for the index record which is
!	to be inserted.
!
!   2.	This routine does not move the key of the last record in the
!	old bucket because the key-buffer currently contains the new
!	high-key value of the next lower level.
!
!   3.	The algorithm for splitting an index bucket is very similat
!	to the same algorithm for splitting a data bucket.  That is,
!	the new record(s) is placed with R(LOW) if possible, and as
!	many R(HIGH) records as will fit will also stay in the old
!	bucket.  If the nrew record(s) will not fit with R(LOW), then
!	it is moved to the new bucket completely with R(HIGH).  This
!	algorithm has the effect that inserting records at the bottom
!	of the bucket will tend to fill the old bucket more than the
!	new bucket.  The alternative, however, is backward scanning of
!	the index records in R(LOW) in order to maximize precisely the
!	split location.  Such a technique is not judged to be worth the
!	extra manipulations required to support it.  Note that this
!	algorithm assumes that at least three index records will fit
!	in an index bucket.  If this ever becomes not true, then
!	extra machinations will be required by this routine.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	indexbd : REF BLOCK,
	newindexbd : REF BLOCK;

    LOCAL
	totalsize,				! Space needed for new records
	sizeofidxrecord,			! Size of one index record
	amounttomove,				! Amount of stuff to move out
	thislevel,				! Level of this index bucket
	bktflags,				! Flags of current index bkt
	newbucket,				! Bkt # of new index bkt
	nextfreebyte,				! Temp
	sizelow,				! Size of R(LOW) records
	spaceneeded,				! Size of new record(s)
	amountofdata,				! Amount of record space used up
	maxdatasize,				! Max space available in empty bkt
	oldindexptr : REF BLOCK,		! Ptr to old index bkt
	endptr : REF BLOCK,			! Ptr to end of bucket
	newindexptr : REF BLOCK;		! Ptr to new index bkt

    REGISTER
	tptr : REF BLOCK,			! Temp pointer
	splitptr : REF BLOCK,			! Ptr to place to split
	insertptr : REF BLOCK;			! Place to insert record

    TRACE ('SPTINDEX');
    !
    !   Get the flags and level number of current bucket
    !
    oldindexptr = .indexbd [bkdbktadr];
    thislevel = .oldindexptr [bhlevel];
    bktflags = .oldindexptr [bhflags] AND bhflgend;	! Leave end bit
    nextfreebyte = .oldindexptr [bhnextbyte];
    !
    !   Allocate a new index bucket
    !

    IF alcbkt (btypeindex, 			! Type
	    .bktflags, 				! Flags
	    .thislevel, 			! Level
	    .newindexbd				! Bucket
	) EQL false
	!
	!   Could we do it?
	!
    THEN
	RETURN false;

    !
    !   Get ptr to the new bucket
    !
    newindexptr = .newindexbd [bkdbktadr];

    !+
    !   We must now compute how much of this bucket should be
    !   moved to the new bucket. The algorithm is described
    !   above
    !-

    !

    !   Compute total size of an index record
    !
    sizeofidxrecord = .kdb [kdbkszw] + irhdrsize;
    lookat ('	SIZE-OF-REC: ', sizeofidxrecord);
    !
    !   Now, we need to figure out how we want to split this bucket
    !
    insertptr = .recdesc [rdrecptr];		! Start at insertion point
    sizelow = .insertptr - .oldindexptr - bhhdrsize;	! Size of R(LOW)
    lookat ('	SIZE-LOW: ', sizelow);
    spaceneeded = .recdesc [rdlength];		! Space we need
    maxdatasize = .kdb [kdbibkz]^b2w;		! Space we have
    !
    !   If the user specified his own load fills, we must use
    !   them.
    !

    IF chkflag (rab [rabrop, 0], roploa) NEQ 0 THEN maxdatasize = .kdb [kdbifloffset];

    maxdatasize = .maxdatasize - bhhdrsize;	! Account for header
    lookat ('	MAX-DATA-SIZE: ', maxdatasize);
    splitptr = .insertptr;			! Assume split here
    !
    !   Can we fit the new record(s) with R(LOW)?
    !

    IF (.sizelow + .spaceneeded) LEQ .maxdatasize
    THEN
    ! The new idx record will go with R(LOW)
	BEGIN
	rtrace (%STRING ('	Index record stays with R-LOW...', 	!
		%CHAR (13), %CHAR (10)));
	sizelow = .sizelow + .spaceneeded;	! Bump counter
	!
	!   Loop over all the records from here down and
	!   keep as many of them as possible (until we go
	!   over one-half of the bucket).
	!
	amountofdata = .oldindexptr [bhnextbyte] - bhhdrsize + .spaceneeded;

	UNTIL .sizelow GTR (.amountofdata^divideby2lsh) DO
	    BEGIN
	    splitptr = .splitptr + .sizeofidxrecord;
	    sizelow = .sizelow + .sizeofidxrecord;	! Bump counter
	    lookat ('	Bump SPLITPTR to: ', splitptr);
	    lookat ('	Bump SIZELOW to: ', sizelow);
	    END

	END
    ELSE
    ! The new record must be moved out with R(HIGH)
	insertptr = .newindexptr + bhhdrsize;	! Reset pointer

    !
    !   Figure out how much must go
    !
    amounttomove = .oldindexptr [bhnextbyte] + .oldindexptr - .splitptr;
    lookat ('	AMT-TO-MOVE:', amounttomove);

%IF dbug
%THEN

    IF .amounttomove LSS 0 THEN rmsbug (msgcount);

%FI

    !
    !   Move the bottom of the index out
    !

    IF .amounttomove NEQ 0
    THEN
	movewords (.splitptr, 			! From
	    .newindexptr + bhhdrsize, 		! To
	    .amounttomove);			! Size

    						!
    !   Reset bucket header data
    !
    oldindexptr [bhnextbyte] = .oldindexptr [bhnextbyte] - .amounttomove;
    newindexptr [bhnextbyte] = bhhdrsize + .amounttomove;
    newindexptr [bhnextbkt] = .oldindexptr [bhnextbkt];
    oldindexptr [bhnextbkt] = .newindexbd [bkdbktno];
    clrflag (oldindexptr [bhflags], bhflgend);	! Clear end flag
    !
    !   Let's see the new headers
    !

%IF dbug
%THEN
    bugout (%STRING ('DUMP OF OLD BKT HEADER: ', %CHAR (13), %CHAR (10)));
    dumpheader (.oldindexptr);
    bugout (%STRING ('DUMP OF NEW INDEX BKT HDR:', %CHAR (13), %CHAR (10)));
    dumpheader (.newindexptr);
%FI

    !
    !   Reset the address where the new record will go
    !
    recdesc [rdrecptr] = .insertptr;
    RETURN true
    END;					! End of SPTINDEX
%SBTTL 'INSRTIRECORD -- insert new record'

GLOBAL ROUTINE insrtirecord (			! Insert new record
    recdesc, indexbd, originalbd, splitbd1, splitbd2) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	INSRTIRECORD inserts a new record into an index bucket.
!	It is called when either an index or a data bucket has split
!	and we need to create a new index entry for the split bucket.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    RECPTR -- address where new record is to be inserted
!	    USERPTR -- address of search key
!	    USERSIZE -- size of search key
!	    COUNT -- number of new buckets in the split (1 for index,
!		    1 or two for data)
!	INDEXBD -- bucket descriptor for index bucket
!	ORIGINALBD -- bucket descriptor of bucket which split;
!		modified to contain same data as INDEXBD
!	SPLITBD1 -- bucket descriptor of new bucket # 1
!	SPLITBD2 -- bucket descriptor of new bucket # 2
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- index update OK
!	FALSE - error
!		Couldn't modify index
!
! SIDE EFFECTS:
!
!	Unknown
!
! NOTES:
!
!   1.	Data splits may involve 2 extra buckets, index splits require
!	only 1 extra bucket.
!
!   2.	On output, the input bucket descriptor of the ORIGINALBD
!	(the bucket that split)  and SPLITBD1 (the newly allocated
!	bucket)  will be modified to reflect the index bucket and any
!	newly allocated index bucket.  Thus, this routine modifies
!	the input args so as to set up for the next call upon itself.
!
!   3.	On input to this routine, the new high-key value for the bucket
!	which split is contained in the bottom half of the RST key buffer.
!	However, if the bucket which split now contains only RRV records,
!	then a new index record need not be created.  This condition is
!	indicated by the "HOHIKEY" flag being set.  If so, we only
!	need to change the old index entry to point to the
!	new (i.e., split) bucket.  This action has the important
!	effect of removing a bucket which contains only RRV's from
!	the vertical tree path.
!
!   4.	All index buckets are written out in this routine.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	indexbd : REF BLOCK,
	originalbd : REF BLOCK,
	splitbd1 : REF BLOCK,
	splitbd2 : REF BLOCK;

    REGISTER
	tempac,
	ptrac : REF BLOCK,			! Temporary pointer
	oldirecordptr : REF BLOCK;

    LOCAL
	insertptr : REF BLOCK,			! Address to insert record
	oldibktptr : REF BLOCK,			! Original index bucket
	newhighkeyptr : REF BLOCK,		! Ptr to new high-key
	totalsize,				! Amount of space needed
	splitflag,				! On if we need to split
	bucketsize,				! Size in words of a bucket
	maxoffset,				! Max offset into bkt before we split
	rootsplitflag,				! On if we split the root
	noofidxrecords,				! Number of index records to create
	freespace,				! Free space left in this buckt
	topofindexptr : REF BLOCK,		! Ptr to top of current bucket
	sizeofidxrecord,			! Guess
	keystringptr : REF BLOCK,		! Ptr to key string
	buckettoindex,				! Bucket number to put in index
	keysizeinwords,
	newindexbd : BLOCK [bdsize];		! Desc for new index bucket

    TRACE ('INSRTIRECORD');
    !
    !   Assume we won't split the index
    !
    rootsplitflag = false;
    splitflag = false;
    noofidxrecords = .recdesc [rdcount];	! Get # of split buckets
    keysizeinwords = .kdb [kdbkszw];
    !
    !   Check some more input values
    !
    checkinput (recdesc [rdcount], GTR, 0);
    checkinput (recdesc [rdcount], LEQ, 2);
    !
    !   Get the address of the current index record
    !
    oldirecordptr = .recdesc [rdrecptr];
    !
    !   Get a pointer to the bottom half of the key-buffer (which
    !   contains the new high-key value for the split bucket)
    !
    newhighkeyptr = .rst [rstkeybuff] + (.fst [fstkbfsize]/2);
    !
    !   Assume that we won't need any further splits
    !
    clrflag (recdesc [rdstatus], rdflgidxupdate);
    !
    !   Compute size of an index record
    !
    sizeofidxrecord = .keysizeinwords + irhdrsize;
    !
    !   Calculate how much space we need and how much we have
    !
    totalsize = .sizeofidxrecord*.noofidxrecords;
    !
    !   Find the location where we will attempt to place
    !   the new index record (just beyond the old index record)
    !
    insertptr = .oldirecordptr + .sizeofidxrecord;
    !
    !   If there is no high-key record in the original bucket,
    !   just change the existing index record to point to the
    !   new bucket
    !

    IF (chkflag (recdesc [rdstatus], rdflgnohikey) NEQ 0)
    THEN
	BEGIN
	rtrace (%STRING ('	NO HI-KEY FOUND', %CHAR (13), %CHAR (10)));
	oldirecordptr [irbucket] = .splitbd1 [bkdbktno];
	!
	!   Adjust the amount of space we will need
	!
	totalsize = .totalsize - .sizeofidxrecord;
	!
	!   Insert new index record before old one
	!
	insertptr = .insertptr - .sizeofidxrecord;
	!
	!   If this is a 2-bucket split (normal case), we can exit
	!

	IF .noofidxrecords EQL 1
	THEN
	! Just release the bucket
	    BEGIN
	    putbkt (nohikeyupdflag, 		! Update
		.indexbd);
	    RETURN true				! Exit OK
	    END

	END;

    !
    !   More pointers
    !
    oldibktptr = (topofindexptr = .indexbd [bkdbktadr]);
    !
    !   We now need to determine the point at which we
    !   should consider the bucket to be full. If user
    !   fill percentages are being used, then we use his
    !   fill offset value; otherwise, we use the end of the
    !   bucket as the limiting factor
    !
    maxoffset = (bucketsize = .kdb [kdbibkz]^b2w);

    IF (chkflag (rab [rabrop, 0], roploa) NEQ 0)
    THEN
    ! The user wants to define a "full" bucket
	maxoffset = .kdb [kdbifloffset];

    lookat ('	MAXOFFSET: ', maxoffset);
    !
    !   Is this bucket full?
    !

    IF (.oldibktptr [bhnextbyte] + .totalsize) GEQ .maxoffset
    THEN
    ! We need to split
	BEGIN
	splitflag = true;
	rtrace (%STRING ('	SPLITTING THE INDEX...', %CHAR (13), %CHAR (10)));
	recdesc [rdlength] = .totalsize;	! Total space we need
	recdesc [rdrecptr] = .insertptr;	! Insert new rec here

	IF sptindex (.recdesc, 			! Record descriptor
		.indexbd, 			! Index
		newindexbd			! New
	    ) EQL false
	THEN
	    RETURN false;

	!
	!   If the root split, we must remember it
	!

	IF (chkflag (topofindexptr [bhflags], bhflgroot) NEQ 0)	!
	THEN
	    rootsplitflag = true;

	!
	!   Now, is the new record going to go into the
	!   new bucket?
	!

	IF .insertptr NEQ (tempac = .recdesc [rdrecptr])
	THEN
	! The new record goes in new bucket
	    BEGIN
	    insertptr = .tempac;
	    topofindexptr = .newindexbd [bkdbktadr]
	    END;

	!
	!   Check that there is enough room to
	!   write the records
	!
	freespace = (.bucketsize) - .topofindexptr [bhnextbyte];

	IF .totalsize GTR .freespace THEN rmsbug (msgnospace)

	END;

    !+
    !   At this point, we can more the records down and
    !   insert the new index records. We have the following:
    !
    !   KEYBUFFER	Contains new high key value
    !   INSERTPTR	Ptr to point at which
    !                   insert is to be done
    !   OLDIRECORDPTR	Ptr to the old index record whose
    !                   key value we must change
    !   TOPOFINDEXPTR	Ptr to top of bkt in which we will
    !                   insert new index record
    !
    !-

    !

    !   Compute the end of the bucket address and check
    !   to see if there are any index records we must move down
    !
    rtrace (%STRING ('	MOVING IDX RECS DOWN...', %CHAR (13), %CHAR (10)));
    ptrac = .topofindexptr + .topofindexptr [bhnextbyte];
    lookat ('	PTRAC: ', ptrac);

    IF .ptrac NEQ .insertptr
    THEN
	movedown (.insertptr, 			! From
	    .ptrac - 1, 			! To
	    .totalsize				! Size
	);					!

    !   If this is a 3-bucket split, create an index record
    !   for the record R(NEW)
    !

    IF .noofidxrecords EQL 2
    THEN
	BEGIN
	rtrace (%STRING ('	CREATING IDX REC FOR R-NEW...', %CHAR (13), %CHAR (10)));
	keystringptr = .recdesc [rduserptr];
	buckettoindex = .splitbd2 [bkdbktno];
	!
	!   Make the index record
	!
	makeirecord (.buckettoindex, 		! Bucket
	    .insertptr, 			! At
	    .keystringptr);			! Key
	!
	!   Bump the insertptr over this index record
	!
	insertptr = .insertptr + .sizeofidxrecord;
	lookat ('	INSERTPTR after creating R-NEW index record: ', 	!
	    insertptr)
	END;					! Of if this was a 3-bkt split

    !
    !   We must now create an index record for the new bucket
    !   which contains R(HIGH). This index record will consist of
    !   its bucket and the key string in the original index
    !   record. Note that in the unusual case that there was a 3-bkt split
    !   and the "NOHIKEY" flag was set, then we don't want to
    !   do all this (if the NOHIKEY flag is set at this point,
    !   it must be a 3-bkt split since we would have exited earlier
    !   if this had been a normal split)
    !

    IF (chkflag (recdesc [rdstatus], rdflgnohikey) EQL 0)
    THEN
	BEGIN
	buckettoindex = .splitbd1 [bkdbktno];	! Get bucket number
	keystringptr = .oldirecordptr + irhdrsize;
	makeirecord (.buckettoindex, 		! Bkt
	    .insertptr, 			! At
	    .keystringptr);			! Key
	!
	!   We have now created all index records. we must
	!   reset the value of the key in the old index record
	!
	movewords (.newhighkeyptr, 		! From
	    .oldirecordptr + irhdrsize, 	! To
	    .keysizeinwords);			! Size
	!
	!   Clear the old "HIKEY" flag and set it in the
	!   new index record if it is already set in the
	!   old one
	!
	insertptr [irflags] = .oldirecordptr [irflags];
	oldirecordptr [irflags] = defirflags
	END;					! Of if nohikey is off

    !
    !   Bump the end-of-bucket pointer in the bucket header
    !
    topofindexptr [bhnextbyte] = .topofindexptr [bhnextbyte] + .totalsize;
    !
    !   We must now check to see if we split the root. If so,
    !   we must allocate a new root bucket that contains an index
    !   record for each of the two new index buckets. Note that
    !   the allocation of the new root should be done before
    !   the old root is written out (below). This is so that,
    !   at worst, some extra index records will exist in the
    !   old root (if a crash occured after the new root
    !   has been written but before the old root can be
    !   written to the file).  If the old root were written first,
    !   the potential would exist for the loss of 1/2 of the data
    !   records in the file because the old root would contain
    !   only half of its former entries.  Also, the root bit
    !   would be off so we could never locate the true index root.
    !

    IF .rootsplitflag NEQ false
    THEN
    ! We must allocate a new root
	BEGIN
	rtrace (%STRING ('	ALLOCATING NEW ROOT...', %CHAR (13), %CHAR (10)));
	RETURN makroot (.indexbd, 		! Bkt
		newindexbd)			! Bkt-2
	END;					! Of if rootsplitflag is on

    !
    !   If we split the index in order to add the new index
    !   record, we must write out that bucket and set up the
    !   new high-key value in the key buffer
    !

    IF .splitflag
    THEN
	BEGIN
	!
	!   Find the last index record in the old index
	!   bucket and move its key into the bottom of the
	!   user's key buffer.
	!
	ptrac = .rst [rstkeybuff] + (.fst [fstkbfsize]/2);
	newhighkeyptr = .oldibktptr + .oldibktptr [bhnextbyte] - .keysizeinwords;
	lookat ('	MOVING NEW HIGH-KEY AT: ', newhighkeyptr);
	movewords (.newhighkeyptr, 		! From
	    .ptrac, 				! To
	    .keysizeinwords);			! Size
	!
	!   Now, write the new bucket out
	!
	putbkt (true, 				! Update it
	    newindexbd)				! Bucket
	END;					! Of if .splitflag

    !
    !   We now need to write out the index bucket into which
    !   we tried to insert the new index record
    !
    putbkt (true, 				! Update
	.indexbd);				! Bucket
    !
    !   If we split, we must modify the input args to
    !   reflect what we've done so we can be called again
    !   easily. Note that this implies that when the data
    !   bucket descriptor is passed to this routine, it
    !   must also be passed in a temp because it will be
    !   destroyed.
    !

    IF .splitflag EQL false THEN RETURN true;	! No more splits needed

    setflag (recdesc [rdstatus], rdflgidxupdate);
    !
    !   Reset the number of buckets in the split so we won't
    !   screw up if we come back to this routine again
    !
    recdesc [rdcount] = 1;
    movebktdesc (indexbd, 			! From
	originalbd);				! To
    !
    !   Make the new bucket the split bucket
    !
    movebktdesc (newindexbd, 			! From
	splitbd1);				! To
    RETURN true
    END;					! End of INSRTIRECORD
%SBTTL 'FNDDATA -- get to data level'

GLOBAL ROUTINE fnddata (recdesc, databd) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	FNDDATA traverses the entire index structure from the
!	root bucket to the data level.  This routine simply locates
!	the root, then calls fndrec to travel to the data level.
!	The index bucket will be released regardless of whether
!	there was an error or not during the index search.
!	If this routine returns success, then the data bucket
!	is mapped and locked;  if not successful, then no buckets
!	are mapped and locked.
!
! FORMAL PARAMETERS
!
!	RECDESC -- record descriptor packet
!	    USERPTR -- address of search key
!	    USERSIZE  -- size of search key
!	DATABD -- bucket descriptor of data level (returned)
!
! IMPLICIT INPUTS
!
!	Unknown.
!
! ROUTINE VALUE:
!
!	TRUE -- data level reached, record position found
!	FALSE - error
!		Tree error
!		Data busy (busy flag will be set)
!
! SIDE EFFECTS:
!
!	Unknown.
!
!--

    BEGIN

    MAP
	recdesc : REF BLOCK,
	databd : REF BLOCK;

    LOCAL
	indexbd : BLOCK [bdsize];		! Bkt descriptor for index

    REGISTER
	savedstatus;

    TRACE ('FNDDATA');
    !
    !   Fetch the root
    !

    IF getroot (.recdesc, indexbd) EQL false THEN RETURN false;

    !
    !   Start search at top and go to data level
    !
    recdesc [rdrecptr] = 0;
    recdesc [rdlevel] = datalevel;		! Go to data
    RETURN fndrec (.recdesc, indexbd, .databd)
	!
	!   Return the result of the search
	!
    END;					! End of FNDDATA

END						! End of Module INDEX

ELUDOM