db2/hash/hash_conv.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997, 1998
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7 #include "config.h"
   8
   9 #ifndef lint
  10 static const char sccsid[] = "@(#)hash_conv.c   10.5 (Sleepycat) 4/10/98";
  11 #endif /* not lint */
  12
  13 #ifndef NO_SYSTEM_INCLUDES
  14 #include <sys/types.h>
  15 #endif
  16
  17 #include "db_int.h"
  18 #include "db_page.h"
  19 #include "db_swap.h"
  20 #include "hash.h"
  21
  22 /*
  23  * __ham_pgin --
  24  *      Convert host-specific page layout from the host-independent format
  25  *      stored on disk.
  26  *
  27  * PUBLIC: int __ham_pgin __P((db_pgno_t, void *, DBT *));
  28  */
  29 int
  30 __ham_pgin(pg, pp, cookie)
  31         db_pgno_t pg;
  32         void *pp;
  33         DBT *cookie;
  34 {
  35         DB_PGINFO *pginfo;
  36         u_int32_t tpgno;
  37
  38         pginfo = (DB_PGINFO *)cookie->data;
  39         tpgno = PGNO((PAGE *)pp);
  40         if (pginfo->needswap)
  41                 M_32_SWAP(tpgno);
  42
  43         if (pg != PGNO_METADATA && pg != tpgno) {
  44                 P_INIT(pp, pginfo->db_pagesize,
  45                     pg, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
  46                 return (0);
  47         }
  48
  49         if (!pginfo->needswap)
  50                 return (0);
  51         return (pg == PGNO_METADATA ?
  52             __ham_mswap(pp) : __db_pgin(pg, pginfo->db_pagesize, pp));
  53 }
  54
  55 /*
  56  * __ham_pgout --
  57  *      Convert host-specific page layout to the host-independent format
  58  *      stored on disk.
  59  *
  60  * PUBLIC: int __ham_pgout __P((db_pgno_t, void *, DBT *));
  61  */
  62 int
  63 __ham_pgout(pg, pp, cookie)
  64         db_pgno_t pg;
  65         void *pp;
  66         DBT *cookie;
  67 {
  68         DB_PGINFO *pginfo;
  69
  70         pginfo = (DB_PGINFO *)cookie->data;
  71         if (!pginfo->needswap)
  72                 return (0);
  73         return (pg == PGNO_METADATA ?
  74             __ham_mswap(pp) : __db_pgout(pg, pginfo->db_pagesize, pp));
  75 }
  76
  77 /*
  78  * __ham_mswap --
  79  *      Swap the bytes on the hash metadata page.
  80  *
  81  * PUBLIC: int __ham_mswap __P((void *));
  82  */
  83 int
  84 __ham_mswap(pg)
  85         void *pg;
  86 {
  87         u_int8_t *p;
  88         int i;
  89
  90         p = (u_int8_t *)pg;
  91         SWAP32(p);              /* lsn part 1 */
  92         SWAP32(p);              /* lsn part 2 */
  93         SWAP32(p);              /* pgno */
  94         SWAP32(p);              /* magic */
  95         SWAP32(p);              /* version */
  96         SWAP32(p);              /* pagesize */
  97         SWAP32(p);              /* ovfl_point */
  98         SWAP32(p);              /* last_freed */
  99         SWAP32(p);              /* max_bucket */
 100         SWAP32(p);              /* high_mask */
 101         SWAP32(p);              /* low_mask */
 102         SWAP32(p);              /* ffactor */
 103         SWAP32(p);              /* nelem */
 104         SWAP32(p);              /* h_charkey */
 105         SWAP32(p);              /* flags */
 106         for (i = 0; i < NCACHED; ++i)
 107                 SWAP32(p);      /* spares */
 108         return (0);
 109 }