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cde/cde/lib/DtSearch/raima/dbswab.c

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/*
* 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
*/
/*
* COMPONENT_NAME: austext
*
* FUNCTIONS: swab_page
*
* ORIGINS: 27
*
* (C) COPYRIGHT International Business Machines Corp. 1996
* All Rights Reserved
* Licensed Materials - Property of IBM
* US Government Users Restricted Rights - Use, duplication or
* disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
*/
/********************* DBSWAB.C **********************************
* $XConsortium: dbswab.c /main/3 1996/10/28 13:59:11 drk $
* July 1996.
* These functions do byte swap and other manipulations on
* vista cache pages to ensure that database files are
* maintained in a canonical format no matter what machine
* they are used on.
* The DtSearch data records are presumed already in external
* file format by code at the DtSearch level (dtsrswab.c).
* These functions use the standard htonl, htons, ntohl, and ntohs
* network conversion functions for byte order neutrality.
* They use the LONG and INT typedefs in vista.h
* to control integer size.
* The external database files are in the canonical,
* big-endian "network" order.
* So that they can be defined as "null" macros on big endian machines,
* the functions (1) always byte swap in place, and (2) always succeed.
*
* $Log$
*/
#include "vista.h"
#include "dbtype.h"
#include "dbswab.h"
#define DEBUG_DBSWAB
#ifdef DEBUG_DBSWAB
#include <stdio.h>
int debugging_dbswab = FALSE;
int debugging_key_swabs = FALSE;
#endif
/********************************/
/* */
/* swab_page */
/* */
/********************************/
/* Performs byte swap on all slots of any cache page except page 0.
* 4-byte timestamp page header already swapped by caller.
*
* WARNING! The algorithms will only work for the
* DtSearch schema. For data pages, they ignore the
* 1-byte optional key flags except for the OR_MISC record.
* The first 6 bytes of each slot (rectype, dba)
* are always byte swapped. Thereafter every 4-bytes
* is swapped as set or member ptrs until we reach
* the data offset. For OR_MISC records we presume
* exactly 1 byte of optional key flags before the
* set/member ptrs.
*/
void swab_page (char *pgbuf, FILE_ENTRY *file_ptr, SWABDIR direction)
{
#if defined(WORDS_BIGENDIAN)
return;
#else
INT slotno;
char *slotptr;
char *cptr;
INT slsize = file_ptr->ft_slsize;
INT slots = file_ptr->ft_slots; /* # slots per page */
INT recno;
INT used_count;
INT key_prefix;
INT curr_offset, data_offset;
INT align_INT;
LONG align_LONG;
/*----------------- DATA PAGES --------------------
* If file is 'data' file, slots begin immediately after
* the page's timestamp. For each slot we have to swap
* the optional set and member tables as well as fixed
* slot header data.
*/
if (file_ptr->ft_type == DATA) {
#ifdef DEBUG_DBSWAB
if (debugging_dbswab) {
printf (__FILE__"073 %s DATA page '%s': slct=%d slsz=%d pgsz=%d\n",
(direction == HTON)? "WRITE" : "READ",
file_ptr->ft_name, (int)file_ptr->ft_slots,
(int)file_ptr->ft_slsize, (int)file_ptr->ft_pgsize);
fflush(stdout);
}
#endif
for ( slotno = 0, slotptr = pgbuf + 4; /* over timestamp */
slotno < slots;
slotno++, slotptr += slsize) {
/* record number (= record type)
* Save the correct host order value in 'recno'.
*/
memcpy (&align_INT, slotptr, sizeof(INT));
if (direction == HTON) {
recno = align_INT;
HTONS (align_INT);
}
else {
NTOHS (align_INT);
recno = align_INT;
}
memcpy (slotptr, &align_INT, sizeof(INT));
/* dba, or delete chain ptr */
memcpy (&align_LONG, slotptr + sizeof(INT), sizeof(LONG));
align_LONG = HTONL (align_LONG);
memcpy (slotptr + sizeof(INT), &align_LONG, sizeof(LONG));
/* If this is a deleted record, we're done */
if (recno & 0x8000)
continue;
/* Swap 4-byte set/member ptrs till we hit data */
recno &= 0x0fff; /* switch off delete and lock bits */
data_offset = record_table[recno].rt_data;
for ( curr_offset = (recno == MISCREC_RECNO)? 7 : 6;
curr_offset < data_offset;
curr_offset += sizeof(LONG)) {
memcpy (&align_LONG, slotptr + curr_offset, sizeof(LONG));
align_LONG = HTONL (align_LONG);
memcpy (slotptr + curr_offset, &align_LONG, sizeof(LONG));
}
} /* end loop on each slot */
} /* end if (data page) */
/*----------------- KEY PAGES --------------------
* DtSearch doesn't use anything but key and data files
* so this must be a key file. A b-tree node = one cache page.
* Before the slots begin in a key file page there is
* additional header data to be swapped after the timestamp:
* the used_slots count (2 bytes) and the orphan ptr (4 bytes).
* If used_slots == 0, then the page is not used and the
* orphan ptr is really a delete chain ptr for the entire node.
*/
else {
/* 'used_slots'
* Save the correct host order value in 'used_count'.
*/
memcpy (&align_INT, pgbuf + 4, sizeof(INT));
if (direction == HTON) {
used_count = align_INT;
HTONS (align_INT);
}
else {
NTOHS (align_INT);
used_count = align_INT;
}
memcpy (pgbuf + 4, &align_INT, sizeof(INT));
/* 'orphan' ptr or 'delete chain' ptr */
memcpy (&align_LONG, pgbuf + 6, sizeof(LONG));
align_LONG = HTONL (align_LONG);
memcpy (pgbuf + 6, &align_LONG, sizeof(LONG));
#ifdef DEBUG_DBSWAB
if (debugging_dbswab || debugging_key_swabs) {
printf (__FILE__
"124 %s KEY page '%s': slct=%d used=%d slsz=%d pgsz=%d\n",
(direction == HTON)? "WRITE" : "READ",
file_ptr->ft_name, (int)slots,
(int)used_count,
(int)slsize, (int)file_ptr->ft_pgsize);
fflush (stdout);
}
#endif
/* For each used slot we have to swap the key prefix
* at the beginning of the slot, then at the *end*
* of the key, the dba, followed by the child node ptr.
* (This is not the format raima published but it's true!)
* Slots start at pg offset 10: timestamp + used_slots + orphan ptr.
* Note that if used_count == 0, we won't process
* this deleted node any further.
*/
for ( slotno = 0, slotptr = pgbuf + 10;
slotno < used_count;
slotno++, slotptr += slsize) {
/* 'key prefix. Save host order value. */
memcpy (&align_INT, slotptr, sizeof(INT));
if (direction == HTON) {
key_prefix = align_INT;
HTONS (align_INT);
}
else {
NTOHS (align_INT);
key_prefix = align_INT;
}
memcpy (slotptr, &align_INT, sizeof(INT));
#ifdef DEBUG_DBSWAB
if (debugging_key_swabs)
printf (" slot #%02d: prefix=%d",
(int)slotno, (int)key_prefix);
#endif
/* database address.
* All DtSearch keys are unswapped char strings.
* The dba is just past the key, 8 bytes before
* of the end of the slot.
*/
cptr = slotptr + slsize - 8;
memcpy (&align_LONG, cptr, sizeof(LONG));
align_LONG = HTONL (align_LONG);
memcpy (cptr, &align_LONG, sizeof(LONG));
#ifdef DEBUG_DBSWAB
if (debugging_key_swabs) {
printf (" dba=x%08lx key='%s'\n", (direction == NTOH)?
(long)align_LONG : (long)ntohl(align_LONG),
slotptr + 2);
fflush (stdout);
}
#endif
/* 'child ptr'. after dba, 4 bytes before end of slot. */
cptr += 4;
memcpy (&align_LONG, cptr, sizeof(LONG));
align_LONG = HTONL (align_LONG);
memcpy (cptr, &align_LONG, sizeof(LONG));
} /* end loop on each slot */
} /* end if (key page) */
return;
#endif /* BYTE_SWAP */
} /* swab_page() */
/********************* DBSWAB.C **********************************/
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