cdesktopenv/cde/lib/tt/mini_isam/isread.c

808 lines
19 KiB
C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these libraries and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/*%% (c) Copyright 1993, 1994 Hewlett-Packard Company */
/*%% (c) Copyright 1993, 1994 International Business Machines Corp. */
/*%% (c) Copyright 1993, 1994 Sun Microsystems, Inc. */
/*%% (c) Copyright 1993, 1994 Novell, Inc. */
/*%% $XConsortium: isread.c /main/3 1995/10/23 11:43:35 rswiston $ */
/*
* Copyright (c) 1988 by Sun Microsystems, Inc.
*/
/*
* isread.c
*
* Description:
* Read a record from ISAM file.
*/
#include "isam_impl.h"
#include <sys/time.h>
static int _amread();
/*
* err = isread(isfd, record, mode)
*
* Isread() reads a new record from an ISAM file.
*
* Current record position is set.
* isrecnum is set to indicate the read record.
*
* If the ISAM file is for variable length records, the isreclen variable
* is set to indicate the actual length of the record.
*
* Returns 0 if successful, or -1 of any error.
*
* Errors:
* ELOCKED The record or the entire file is locked by another process.
* ENOTOPEN isfd does not correspond to an open ISAM file, or the
* ISAM file was opened with ISOUTPUT mode.
* EBADARG Bad mode parameter.
* ENOCURR Mode is ISCURR and the current record position is not set.
* ENOREC Specified record cannot be found (random access read)
* EENDFILE The end file of is reached (sequential read).
* EBADKEY Index was deleted by other process (can happen only
* when lock file is purged).
*/
int
isread(int isfd, char *record, int mode)
{
Fab *fab;
int reclen;
Recno recnum;
int ret;
enum readmode readmode;
/*
* Get File Access Block.
*/
if ((fab = _isfd_find(isfd)) == NULL) {
_setiserrno2(ENOTOPEN, '9', '0');
return (ISERROR);
}
/*
* Check that the open mode was ISINPUT, or ISINOUT.
*/
if (fab->openmode != OM_INPUT && fab->openmode != OM_INOUT) {
_setiserrno2(ENOTOPEN, '9', '0');
return (ISERROR);
}
/*
* Extract read mode.
*/
if ((readmode = _getreadmode(mode)) == RM_BADMODE) {
_setiserrno2(EBADARG, '9', '0');
return (ISERROR);
}
/*
* All keys must be in the minimum record length.
* So send just the minimum length part of the record.
*/
reclen = fab->minreclen;
/*
* Call the Access Method
*/
recnum = isrecnum;
if ((ret = _amread(&fab->isfhandle, record, &reclen,
readmode, &fab->curpos, &recnum,
&fab->errcode)) == ISOK) {
isrecnum = recnum; /* Set isrecnum */
}
isreclen = reclen;
_seterr_errcode(&fab->errcode);
return (ret); /* Successful read */
}
/*
* _amread(isfhandle, record, reclen, readmode, curpos, recnum, errcode)
*
* _amread() reads a record from ISAM file
*
* Input params:
* isfhandle Handle of ISAM file
* readmode Specifies access mode (random or sequential)
* curpos current record position
* recnum copy if isrecnum
*
* Output params:
* curpos new current position
* recnum record number
* errcode error status of the operation
* reclen actual length of the record
* record filled with data
*
*/
static int
_amread(Bytearray *isfhandle, char *record, int *reclen,
enum readmode readmode, Bytearray *curpos, Recno *recnum,
struct errcode *errcode)
{
Fcb *fcb = NULL;
Recno recnum2;
int err;
Crp *crp;
Btree *btree = NULL;
Keydesc2 *pkeydesc2;
char keybuf1[MAXKEYSIZE], keybuf2[MAXKEYSIZE];
char *pkey, *pkeynext;
int skipbytes;
int ret;
Bytearray oldcurpos;
int (*rec_read)();
_isam_entryhook();
/*
* Get FCB corresponding to the isfhandle handle.
*/
if ((fcb = _openfcb(isfhandle, errcode)) == NULL) {
_isam_exithook();
return (ISERROR);
}
rec_read = (fcb->varflag?_vlrec_read:_flrec_read);
/*
* Update information in FCB from CNTL page on the disk
*/
(void)_isfcb_cntlpg_r2(fcb);
/*
* Save the old record position.
*/
oldcurpos = _bytearr_dup(curpos);
/*
* Get info from current record position structure.
*/
crp = (Crp *) curpos->data;
if (crp->keyid == PHYS_ORDER) {
/*
* Physical order in use.
*/
switch (readmode) {
case RM_EQUAL:
recnum2 = *recnum; /* passed from isrecnum */
if ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
break;
case RM_GREAT:
recnum2 = *recnum + 1;
if (recnum2 < 1) recnum2 = 1;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2++;
if (err != ISOK) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
break;
case RM_GTEQ:
recnum2 = *recnum;
if (recnum2 < 1) recnum2 = 1;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2++;
if (err != ISOK) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
break;
case RM_LESS:
recnum2 = *recnum - 1;
if (recnum2 > fcb->lastrecno) recnum2 = fcb->lastrecno;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2--;
if (err != ISOK) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
break;
case RM_LTEQ:
recnum2 = *recnum;
if (recnum2 > fcb->lastrecno) recnum2 = fcb->lastrecno;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2--;
if (err != ISOK) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
break;
case RM_FIRST:
recnum2 = 1;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2++;
if (err != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
break;
case RM_CURR:
switch (crp->flag) {
case CRP_ON:
case CRP_BEFORE:
case CRP_AFTER:
recnum2 = crp->recno;
break;
case CRP_BEFOREANY:
recnum2 = 1;
break;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
if( rec_read(fcb, record, recnum2, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
break;
case RM_NEXT:
switch (crp->flag) {
case CRP_ON:
case CRP_AFTER:
recnum2 = crp->recno + 1;
break;
case CRP_BEFOREANY:
recnum2 = 1;
break;
case CRP_BEFORE:
recnum2 = crp->recno;
break;
case CRP_AFTERANY:
_amseterrcode(errcode, EENDFILE);
goto ERROR;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2++;
if (err != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
break;
case RM_PREV:
switch (crp->flag) {
case CRP_ON:
case CRP_BEFORE:
recnum2 = crp->recno - 1;
break;
case CRP_AFTER:
recnum2 = crp->recno;
break;
case CRP_BEFOREANY:
_amseterrcode(errcode, EENDFILE);
goto ERROR;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2--;
if (err != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
break;
case RM_LAST:
recnum2 = fcb->lastrecno;
/*
* Skip deleted records.
*/
while ((err = rec_read(fcb, record, recnum2, reclen)) != ISOK &&
err == ENOREC)
recnum2--;
if (err != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
break;
default:
_isfatal_error("Invalid readmode");
}
*recnum = recnum2;
/*
* Set new current record position.
*/
crp->recno = recnum2;
crp->flag = CRP_ON;
} /* physical order */
else {
/*
* Find key descriptor in FCB
*/
if ((pkeydesc2 = _isfcb_indfindkey(fcb, crp->keyid)) == NULL) {
_amseterrcode(errcode, EBADKEY);
goto ERROR;
}
/*
* skipkeybytes is set to the number of bytes in the beginning
* of the key:
* RECNOSIZE for ISNODUPS keys to skip recno part
* RECNOSIZE + DUPIDSIZE to skip recno and duplicate serial number
*/
skipbytes = RECNOSIZE;
if (ALLOWS_DUPS2(pkeydesc2))
skipbytes += DUPIDSIZE;
/*
* Create B tree object.
*/
btree = _isbtree_create(fcb, pkeydesc2);
switch (readmode) {
case RM_EQUAL:
case RM_GTEQ:
/*
* Make sure that you will read the first duplicate.
*/
_iskey_fillmin(pkeydesc2, keybuf1);
/*
* Extract key fields from record.
*/
_iskey_extract(pkeydesc2, record, keybuf2);
memcpy((void *)(keybuf1 + skipbytes),
(const void *)(keybuf2 + skipbytes), crp->matchkeylen);
/*
* Position pointer in the B-tree in before the searched value.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_next(btree)) == NULL) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
if (readmode == RM_EQUAL &&
memcmp(keybuf1 + skipbytes, pkey + skipbytes,
crp->matchkeylen) != 0) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_GREAT:
/*
* Make sure that you will read past all matching records.
*/
_iskey_fillmax(pkeydesc2, keybuf1);
/*
* Extract key fields from record.
*/
_iskey_extract(pkeydesc2, record, keybuf2);
memcpy((void *)(keybuf1 + skipbytes),
(const void *)(keybuf2 + skipbytes), crp->matchkeylen);
/*
* Position pointer in the B-tree in before the searched value.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_next(btree)) == NULL) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_LESS:
/*
* Make sure that you will read before all matching records.
*/
_iskey_fillmin(pkeydesc2, keybuf1);
/*
* Extract key fields from record.
*/
_iskey_extract(pkeydesc2, record, keybuf2);
memcpy((void *)(keybuf1 + skipbytes),
(const void *)(keybuf2 + skipbytes), crp->matchkeylen);
/*
* Position pointer in the B-tree in before the searched value.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_current(btree)) == NULL) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_LTEQ:
/*
* Make sure that you will read the last duplicate.
*/
_iskey_fillmax(pkeydesc2, keybuf1);
/*
* Extract key fields from record.
*/
_iskey_extract(pkeydesc2, record, keybuf2);
memcpy((void *)(keybuf1 + skipbytes),
(const void *)(keybuf2 + skipbytes), crp->matchkeylen);
/*
* Position pointer in the B-tree in before the searched value.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_current(btree)) == NULL) {
_amseterrcode(errcode, ENOREC);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_CURR:
switch (crp->flag) {
case CRP_ON:
case CRP_BEFORE:
case CRP_AFTER:
/*
* We have check if the record has not been deleted
* since the current record position was set up.
*/
_isbtree_search(btree, crp->key);
pkey = _isbtree_current(btree);
if (pkey == NULL ||
ldrecno(pkey + KEY_RECNO_OFF) != crp->recno) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
break;
case CRP_BEFOREANY:
_isbtree_search(btree, crp->key);
pkey = _isbtree_next(btree);
if (pkey == NULL) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
break;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_NEXT:
/*
* Validate that current position has been set.
*/
switch (crp->flag) {
case CRP_ON:
case CRP_BEFORE:
case CRP_BEFOREANY:
break;
case CRP_AFTERANY:
_amseterrcode(errcode, EENDFILE);
goto ERROR;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
/*
* Position pointer to current position.
*/
_isbtree_search(btree, crp->key);
if (crp->flag == CRP_BEFORE)
pkey = _isbtree_current(btree);
else
/* crp->flag == CRP_ON || crp->flag == CRP_BEFOREANY */
pkey = _isbtree_next(btree);
if (pkey == NULL) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_PREV:
/*
* Validate that current position has been set.
*/
switch (crp->flag) {
case CRP_ON:
case CRP_BEFORE:
/*
* To get to the previous record, we must decrement
* the TID part for unique keys, or duplicate serial number
* for non-unique keys.
*/
memcpy((void *)keybuf1,
(const void *)crp->key, pkeydesc2->k2_len);
if (ALLOWS_DUPS2(pkeydesc2)) {
stlong(ldlong(keybuf1 + KEY_DUPS_OFF) - 1,
keybuf1 + KEY_DUPS_OFF);
}
else {
strecno(ldrecno(keybuf1 + KEY_RECNO_OFF) - 1,
keybuf1 + KEY_RECNO_OFF);
}
break;
case CRP_AFTER:
memcpy((void *)keybuf1, (const void *)crp->key, pkeydesc2->k2_len);
break;
case CRP_BEFOREANY:
_amseterrcode(errcode, EENDFILE);
goto ERROR;
default:
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
/*
* Position pointer to current position.
*/
_isbtree_search(btree, keybuf1);
pkey = _isbtree_current(btree);
if (pkey == NULL) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, ENOCURR);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_FIRST:
/*
* Fill key buffer with -infinity.
*/
_iskey_fillmin(pkeydesc2, keybuf1);
/*
* Position pointer in the B-tree before any key entry.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_next(btree)) == NULL) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
recnum2 = crp->recno;
break;
case RM_LAST:
/*
* Fill key buffer with +infinity.
*/
_iskey_fillmax(pkeydesc2, keybuf1);
/*
* Position pointer in the B-tree before any key entry.
*/
_isbtree_search(btree, keybuf1);
if ((pkey = _isbtree_current(btree)) == NULL) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
crp->recno = ldrecno(pkey + KEY_RECNO_OFF);
memcpy((void *)crp->key, (const void *)pkey, pkeydesc2->k2_len);
if( rec_read(fcb, record, crp->recno, reclen) != ISOK) {
_amseterrcode(errcode, EENDFILE);
goto ERROR;
}
recnum2 = crp->recno;
break;
default:
_isfatal_error("Invalid readmode");
}
*recnum = recnum2;
crp->flag = CRP_ON;
/*
* Set up isdupl to handle isstat2 value for keys that allow
* duplicate values.
*/
if (ALLOWS_DUPS2(pkeydesc2) && (pkeynext = _isbtree_next(btree)) &&
memcmp(pkey + skipbytes, pkeynext + skipbytes,
crp->matchkeylen) == 0) {
isdupl = 1;
}
_isbtree_destroy(btree);
}
_amseterrcode(errcode, ISOK);
ret = ISOK;
/* Clean-up work. */
_isdisk_commit(); /* This will only check
* that we unfixed all fixed
* buffers */
_isdisk_inval();
_bytearr_free(&oldcurpos);
_isam_exithook();
return (ret);
ERROR:
*reclen = 0;
_isdisk_inval();
_bytearr_free(&oldcurpos);
/*
* If error is ENOREC, set the current record position undefined.
*/
if (errcode->iserrno == ENOREC || errcode->iserrno == EENDFILE) {
((Crp *)curpos->data)->flag = CRP_UNDEF;
}
if (btree != NULL)
_isbtree_destroy(btree);
_isam_exithook();
return (ISERROR);
}