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622 lines
15 KiB
C
622 lines
15 KiB
C
/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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/*%% (c) Copyright 1993, 1994 Hewlett-Packard Company */
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/*%% (c) Copyright 1993, 1994 International Business Machines Corp. */
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/*%% (c) Copyright 1993, 1994 Sun Microsystems, Inc. */
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/*%% (c) Copyright 1993, 1994 Novell, Inc. */
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/*%% $XConsortium: isstart.c /main/3 1995/10/23 11:45:08 rswiston $ */
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#ifndef lint
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static char sccsid[] = "@(#)isstart.c 1.9 89/07/17 Copyr 1988 Sun Micro";
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#endif
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/*
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* Copyright (c) 1988 by Sun Microsystems, Inc.
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*/
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/*
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* isstart.c
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*
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* Description:
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* Select index and set record position.
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*/
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#include "isam_impl.h"
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#include <sys/time.h>
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#include <stdlib.h>
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static int _amstart();
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/*
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* err = isstart(isfd, keydesc, length, record, mode)
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*
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* Isstart() selects index for subsequent read operations and set new
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* current record position.
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*
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* isrecnum is set to indicate the start record.
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*
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*
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* Returns 0 if successful, or -1 of any error.
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*
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* Errors:
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* ENOTOPEN isfd does not correspond to an open ISAM file, or the
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* ISAM file was opened with ISOUTPUT mode.
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* EBADARG Bad mode parameter.
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* EBADARG keylen is out of range.
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* ENOREC Specified record cannot be found (random access read).
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* EBADKEY Error in the key descriptor.
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*/
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int
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isstart(int isfd, struct keydesc *keydesc, int length, char *record,
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int mode)
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{
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Fab *fab;
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int reclen;
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Recno recnum;
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int ret;
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enum readmode readmode;
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char dummy_record [1]; /* used for ISFIRST and ISLAST */
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char *precord;
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/*
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* Get File Access Block.
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*/
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if ((fab = _isfd_find(isfd)) == NULL) {
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_setiserrno2(ENOTOPEN, '9', '0');
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return (ISERROR);
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}
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/*
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* Check that the open mode was ISINPUT, or ISINOUT.
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*/
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if (fab->openmode != OM_INPUT && fab->openmode != OM_INOUT) {
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_setiserrno2(ENOTOPEN, '9', '0');
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return (ISERROR);
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}
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/*
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* Extract read mode.
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*/
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if ((readmode = _getreadmode(mode)) == RM_BADMODE) {
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_setiserrno2(EBADARG, '9', '0');
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return (ISERROR);
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}
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/*
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* Some arguments are used only when a particular mode is specified.
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*/
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if (readmode == RM_FIRST || readmode == RM_LAST || USE_PHYS_ORDER(keydesc)) {
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precord = dummy_record;
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reclen = 0;
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}
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else {
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precord = record;
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reclen = fab->minreclen;
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}
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reclen = fab->minreclen;
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recnum = isrecnum;
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if ((ret = _amstart(&fab->isfhandle, precord, reclen,
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readmode, keydesc, length, &fab->curpos,
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&recnum, &fab->errcode)) == ISOK) {
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isrecnum = recnum; /* Set isrecnum */
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}
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_seterr_errcode(&fab->errcode);
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return (ret); /* Successful start */
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}
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/*
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* _amstart(isfhandle, record, reclen, readmode,
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* keydesc, keylen, curpos, recnum, errcode)
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*
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* _amstart() reads a record from ISAM file
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*
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* Input params:
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* isfhandle Handle of ISAM file
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* readmode Specifies access mode (random or sequential)
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* curpos old record position
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* recnum copy of isrecnum
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* keydesc key descriptor
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* keylen # of bytes of key to match
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* record extract key from this record buffer
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*
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* Output params:
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* curpos new current position
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* recnum record number
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* errcode error status of the operation
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* reclen actual length of the record
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*
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* Note:
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* Successfull isstart() returns the new curpos and frees the old curpos.
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*/
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/* ARGSUSED */
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static int
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_amstart(Bytearray *isfhandle, char *record, int *reclen,
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enum readmode readmode, struct keydesc *keydesc, int keylen,
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Bytearray *curpos, Recno *recnum, struct errcode *errcode)
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{
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Fcb *fcb;
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Recno recnum2;
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int err;
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Crp *newcrp = NULL;
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char recbuf [ISMAXRECLEN];
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Keydesc2 keydesc2;
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Keydesc2 *pkeydesc2;
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int newcrpsize = 0;
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char keybuf1 [MAXKEYSIZE], keybuf2 [MAXKEYSIZE];
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int matchkeylen;
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int skipbytes;
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char *pkey;
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Btree *btree = NULL;
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int reclen2;
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int (*rec_read)();
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_isam_entryhook();
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/*
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* Get FCB corresponding to the isfhandle handle.
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*/
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if ((fcb = _openfcb(isfhandle, errcode)) == NULL) {
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_isam_exithook();
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return (ISERROR);
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}
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rec_read = (fcb->varflag?_vlrec_read:_flrec_read);
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/*
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* Update information in FCB from CNTL page on the disk
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*/
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(void)_isfcb_cntlpg_r2(fcb);
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if (USE_PHYS_ORDER(keydesc)) {
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/*
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* Physical order in use.
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*/
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/*
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* Allocate new current position structure.
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*/
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newcrpsize = sizeof(*newcrp);
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newcrp = (Crp *) _ismalloc(sizeof(*newcrp));
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memset ((char *)newcrp, 0, sizeof(*newcrp));
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newcrp->keyid = PHYS_ORDER;
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switch (readmode) {
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case RM_EQUAL:
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recnum2 = *recnum; /* passed from isrecnum */
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if ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = recnum2;
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break;
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case RM_GREAT:
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recnum2 = *recnum + 1;
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if (recnum2 < 1) recnum2 = 1;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2++;
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if (err != ISOK) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = recnum2;
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break;
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case RM_GTEQ:
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recnum2 = *recnum;
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if (recnum2 < 1) recnum2 = 1;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2++;
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if (err != ISOK) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = recnum2;
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break;
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case RM_LESS:
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recnum2 = *recnum - 1;
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if (recnum2 > fcb->lastrecno) recnum2 = fcb->lastrecno;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2--;
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if (err != ISOK) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_AFTER;
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newcrp->recno = recnum2;
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break;
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case RM_LTEQ:
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recnum2 = *recnum;
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if (recnum2 > fcb->lastrecno) recnum2 = fcb->lastrecno;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2--;
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if (err != ISOK) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_AFTER;
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newcrp->recno = recnum2;
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break;
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case RM_FIRST:
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recnum2 = 1;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2++;
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if (err == ISOK) {
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = recnum2;
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}
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else {
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newcrp->flag = CRP_AFTERANY;
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}
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break;
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case RM_LAST:
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recnum2 = fcb->lastrecno;
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/*
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* Skip deleted records.
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*/
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while ((err = rec_read(fcb, recbuf, recnum2, &reclen2)) != ISOK &&
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err == ENOREC)
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recnum2--;
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if (err == ISOK) {
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newcrp->flag = CRP_AFTER;
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newcrp->recno = recnum2;
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}
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else {
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newcrp->flag = CRP_BEFOREANY;
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}
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break;
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default:
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_isfatal_error("Invalid readmode");
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}
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*recnum = recnum2;
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/*
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* Build new curpos, deallocate old curpos.
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*/
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_bytearr_free(curpos);
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*curpos = _bytearr_new(sizeof(*newcrp), (char *)newcrp);
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} /* physical order */
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else {
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/*
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* Use order defined by some key.
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*/
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/*
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* Check key descriptor for validity.
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*/
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if (_validate_keydesc(keydesc, fcb->minreclen) != ISOK) {
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_amseterrcode(errcode, EBADKEY);
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goto ERROR;
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}
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/*
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* Convert key descriptor to internal form.
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*/
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_iskey_xtoi (&keydesc2, keydesc);
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/* Find key decriptor in the FCB. */
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if ((pkeydesc2 = _isfcb_findkey(fcb ,&keydesc2)) == NULL) {
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_amseterrcode(errcode, EBADKEY);
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goto ERROR;
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}
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/*
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* skipkeybytes is set to the number of bytes in the beginning
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* of the key:
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* RECNOSIZE for ISNODUPS keys to skip recno part
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* RECNOSIZE + DUPIDSIZE to skip recno and duplicate serial number
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*/
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skipbytes = RECNOSIZE;
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if (ALLOWS_DUPS2(pkeydesc2))
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skipbytes += DUPIDSIZE;
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/*
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* Validate keylen.
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*/
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if (keylen < 0 || keylen > pkeydesc2->k2_len - skipbytes) {
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_amseterrcode(errcode, EBADARG);
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goto ERROR;
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}
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/*
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* Special case if keylen == 0: use the entire key.
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*/
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if (keylen == 0)
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matchkeylen = pkeydesc2->k2_len - skipbytes;
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else
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matchkeylen = keylen;
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/*
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* Allocate new current record position.
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*/
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newcrpsize = sizeof(Crp) + pkeydesc2->k2_len;
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newcrp = (Crp *) _ismalloc((unsigned)newcrpsize);
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memset((char *)newcrp, 0, newcrpsize);
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newcrp->keyid = pkeydesc2->k2_keyid; /* Key identifier in FCB */
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newcrp->matchkeylen = matchkeylen; /* number of bytes to match */
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/*
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* Create B tree object.
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*/
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btree = _isbtree_create(fcb, pkeydesc2);
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switch (readmode) {
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case RM_EQUAL:
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case RM_GTEQ:
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/*
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* Make sure that you will read the first duplicate.
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*/
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_iskey_fillmin(pkeydesc2, keybuf1);
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/*
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* Extract key fields from record.
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*/
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_iskey_extract(pkeydesc2, record, keybuf2);
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memcpy( keybuf1 + skipbytes,keybuf2 + skipbytes, matchkeylen);
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/*
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* Position pointer in the B-tree in before the searched value.
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*/
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_isbtree_search(btree, keybuf1);
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if ((pkey = _isbtree_next(btree)) == NULL) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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if (readmode == RM_EQUAL &&
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memcmp(keybuf1 + skipbytes, pkey + skipbytes,
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matchkeylen) != 0) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
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memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
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break;
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case RM_GREAT:
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/*
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* Make sure that you will read past all matching records.
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*/
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_iskey_fillmax(pkeydesc2, keybuf1);
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/*
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* Extract key fields from record.
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*/
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_iskey_extract(pkeydesc2, record, keybuf2);
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memcpy( keybuf1 + skipbytes,keybuf2 + skipbytes, matchkeylen);
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/*
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* Position pointer in the B-tree after the searched value.
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*/
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_isbtree_search(btree, keybuf1);
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if ((pkey = _isbtree_next(btree)) == NULL) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
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memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
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break;
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case RM_LESS:
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/*
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* Make sure that you will read before all matching records.
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*/
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_iskey_fillmin(pkeydesc2, keybuf1);
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/*
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* Extract key fields from record.
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*/
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_iskey_extract(pkeydesc2, record, keybuf2);
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memcpy( keybuf1 + skipbytes,keybuf2 + skipbytes, matchkeylen);
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/*
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* Position pointer in the B-tree after the searched value.
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*/
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_isbtree_search(btree, keybuf1);
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if ((pkey = _isbtree_current(btree)) == NULL) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_AFTER;
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newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
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memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
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break;
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case RM_LTEQ:
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/*
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* Make sure that you will the last duplicate.
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*/
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_iskey_fillmax(pkeydesc2, keybuf1);
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/*
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* Extract key fields from record.
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*/
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_iskey_extract(pkeydesc2, record, keybuf2);
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memcpy( keybuf1 + skipbytes,keybuf2 + skipbytes, matchkeylen);
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/*
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* Position pointer in the B-tree in before the searched value.
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*/
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_isbtree_search(btree, keybuf1);
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if ((pkey = _isbtree_current(btree)) == NULL) {
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_amseterrcode(errcode, ENOREC);
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goto ERROR;
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}
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newcrp->flag = CRP_AFTER;
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newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
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memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
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break;
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case RM_FIRST:
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/*
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* Fill key buffer with -infinity.
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*/
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_iskey_fillmin(pkeydesc2, keybuf1);
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/*
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* Position pointer in the B-tree before any key entry.
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*/
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_isbtree_search(btree, keybuf1);
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if ((pkey = _isbtree_next(btree)) == NULL) {
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newcrp->flag = CRP_AFTERANY;
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}
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else {
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newcrp->flag = CRP_BEFORE;
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newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
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memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
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}
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break;
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case RM_LAST:
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/*
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* Fill key buffer with +infinity.
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*/
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_iskey_fillmax(pkeydesc2, keybuf1);
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|
/*
|
|
* Position pointer in the B-tree after all entries.
|
|
*/
|
|
_isbtree_search(btree, keybuf1);
|
|
|
|
if ((pkey = _isbtree_current(btree)) == NULL) {
|
|
newcrp->flag = CRP_BEFOREANY;
|
|
}
|
|
else {
|
|
newcrp->flag = CRP_AFTER;
|
|
newcrp->recno = ldrecno(pkey + KEY_RECNO_OFF);
|
|
memcpy( newcrp->key,pkey, pkeydesc2->k2_len);
|
|
}
|
|
break;
|
|
|
|
default:
|
|
_isfatal_error("Invalid readmode");
|
|
}
|
|
|
|
*recnum = newcrp->recno;
|
|
|
|
/*
|
|
* Build new curpos, deallocate old curpos data.
|
|
*/
|
|
_bytearr_free(curpos);
|
|
*curpos = _bytearr_new((u_short)newcrpsize, (char *)newcrp);
|
|
|
|
_isbtree_destroy(btree);
|
|
}
|
|
|
|
_amseterrcode(errcode, ISOK);
|
|
|
|
/* Clean-up work. */
|
|
free(newcrp);
|
|
|
|
_isdisk_commit(); /* This will only check
|
|
* that we unfixed all fixed
|
|
* buffers */
|
|
_isdisk_inval();
|
|
|
|
_isam_exithook();
|
|
return (ISOK);
|
|
|
|
ERROR:
|
|
|
|
if (btree != NULL)
|
|
_isbtree_destroy(btree);
|
|
|
|
/*
|
|
* If error is EBADKEY, make the current position undefined.
|
|
*/
|
|
if (errcode->iserrno == EBADKEY) {
|
|
((Crp *)curpos->data)->flag = CRP_UNDEF;
|
|
}
|
|
|
|
/*
|
|
* If error is ENOREC, switch to the new key, but set the current
|
|
* record position undefined.
|
|
*/
|
|
if (errcode->iserrno == ENOREC && newcrp != NULL) {
|
|
_bytearr_free(curpos);
|
|
*curpos = _bytearr_new((u_short)newcrpsize, (char *)newcrp);
|
|
((Crp *)curpos->data)->flag = CRP_UNDEF;
|
|
}
|
|
|
|
if (newcrp != NULL)
|
|
free((char *)newcrp);
|
|
_isdisk_inval();
|
|
|
|
_isam_exithook();
|
|
return (ISERROR);
|
|
}
|
|
|
|
|