db2/hash/hash_conv.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7 #include "config.h"
   8
   9 #ifndef lint
  10 static const char sccsid[] = "@(#)hash_conv.c   10.3 (Sleepycat) 6/21/97";
  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  * __h_pgin, __ham_pgout --
  24  *      Convert host-specific page layout to/from the host-independent
  25  *      format stored on disk.
  26  *
  27  * PUBLIC: int __ham_pgin __P((db_pgno_t, void *, DBT *));
  28  * PUBLIC: int __ham_pgout __P((db_pgno_t, void *, DBT *));
  29  */
  30 int
  31 __ham_pgin(pg, pp, cookie)
  32         db_pgno_t pg;
  33         void *pp;
  34         DBT *cookie;
  35 {
  36         DB_PGINFO *pginfo;
  37         u_int32_t tpgno;
  38
  39         pginfo = (DB_PGINFO *)cookie->data;
  40         tpgno = PGNO((PAGE *)pp);
  41         if (pginfo->needswap)
  42                 M_32_SWAP(tpgno);
  43
  44         if (pg != PGNO_METADATA && pg != tpgno) {
  45                 P_INIT(pp, pginfo->db_pagesize,
  46                     pg, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
  47                 return (0);
  48         }
  49
  50         if (!pginfo->needswap)
  51                 return (0);
  52         return (pg == PGNO_METADATA ? __ham_mswap(pp) : __db_pgin(pg, pp));
  53 }
  54
  55 int
  56 __ham_pgout(pg, pp, cookie)
  57         db_pgno_t pg;
  58         void *pp;
  59         DBT *cookie;
  60 {
  61         DB_PGINFO *pginfo;
  62
  63         pginfo = (DB_PGINFO *)cookie->data;
  64         if (!pginfo->needswap)
  65                 return (0);
  66         return (pg == PGNO_METADATA ? __ham_mswap(pp) : __db_pgout(pg, pp));
  67 }
  68
  69 /*
  70  * __ham_mswap --
  71  *      Swap the bytes on the hash metadata page.
  72  *
  73  * PUBLIC: int __ham_mswap __P((void *));
  74  */
  75 int
  76 __ham_mswap(pg)
  77         void *pg;
  78 {
  79         u_int8_t *p;
  80         int i;
  81
  82         p = (u_int8_t *)pg;
  83         SWAP32(p);              /* lsn part 1 */
  84         SWAP32(p);              /* lsn part 2 */
  85         SWAP32(p);              /* pgno */
  86         SWAP32(p);              /* magic */
  87         SWAP32(p);              /* version */
  88         SWAP32(p);              /* pagesize */
  89         SWAP32(p);              /* ovfl_point */
  90         SWAP32(p);              /* last_freed */
  91         SWAP32(p);              /* max_bucket */
  92         SWAP32(p);              /* high_mask */
  93         SWAP32(p);              /* low_mask */
  94         SWAP32(p);              /* ffactor */
  95         SWAP32(p);              /* nelem */
  96         SWAP32(p);              /* h_charkey */
  97         SWAP32(p);              /* flags */
  98         for (i = 0; i < NCACHED; ++i)
  99                 SWAP32(p);      /* spares */
 100         return (0);
 101 }