hash_conv.c

00001 /*-
00002  * See the file LICENSE for redistribution information.
00003  *
00004  * Copyright (c) 1996, 1997, 1998, 1999, 2000
00005  * Sleepycat Software. All rights reserved.
00006  */
00007 #include "config.h"
00008 
00009 #ifndef lint
00010 static const char revid[] = "$Id: hash__conv_8c-source.html,v 1.1 2008年06月08日 10:19:24 sebdiaz Exp $";
00011 #endif /* not lint */
00012 
00013 #ifndef NO_SYSTEM_INCLUDES
00014 #include <sys/types.h>
00015 #endif
00016 
00017 #include "db_int.h"
00018 #include "db_page.h"
00019 #include "db_swap.h"
00020 #include "hash.h"
00021 
00022 /*
00023  * CDB___ham_pgin --
00024  * Convert host-specific page layout from the host-independent format
00025  * stored on disk.
00026  *
00027  * PUBLIC: int CDB___ham_pgin __P((DB_ENV *, db_pgno_t, void *, DBT *));
00028  */
00029 int
00030 CDB___ham_pgin(dbenv, pg, pp, cookie)
00031 DB_ENV *dbenv;
00032 db_pgno_t pg;
00033 void *pp;
00034 DBT *cookie;
00035 {
00036 DB_PGINFO *pginfo;
00037 PAGE *h;
00038 
00039 h = pp;
00040 pginfo = (DB_PGINFO *)cookie->data;
00041 
00042 /*
00043  * The hash access method does blind reads of pages, causing them
00044  * to be created. If the type field isn't set it's one of them,
00045  * initialize the rest of the page and return.
00046  */
00047 if (TYPE(h) != P_HASHMETA && h->pgno == PGNO_INVALID) {
00048 P_INIT(pp, pginfo->db_pagesize,
00049 pg, PGNO_INVALID, PGNO_INVALID, 0, P_HASH, 0);
00050 return (0);
00051 }
00052 
00053 if (!pginfo->needswap)
00054 return (0);
00055 
00056 return (TYPE(h) == P_HASHMETA ? CDB___ham_mswap(pp) :
00057 CDB___db_byteswap(dbenv, pg, pp, pginfo->db_pagesize, 1));
00058 }
00059 
00060 /*
00061  * CDB___ham_pgout --
00062  * Convert host-specific page layout to the host-independent format
00063  * stored on disk.
00064  *
00065  * PUBLIC: int CDB___ham_pgout __P((DB_ENV *, db_pgno_t, void *, DBT *));
00066  */
00067 int
00068 CDB___ham_pgout(dbenv, pg, pp, cookie)
00069 DB_ENV *dbenv;
00070 db_pgno_t pg;
00071 void *pp;
00072 DBT *cookie;
00073 {
00074 DB_PGINFO *pginfo;
00075 PAGE *h;
00076 
00077 pginfo = (DB_PGINFO *)cookie->data;
00078 if (!pginfo->needswap)
00079 return (0);
00080 
00081 h = pp;
00082 return (TYPE(h) == P_HASHMETA ? CDB___ham_mswap(pp) :
00083 CDB___db_byteswap(dbenv, pg, pp, pginfo->db_pagesize, 0));
00084 }
00085 
00086 /*
00087  * CDB___ham_mswap --
00088  * Swap the bytes on the hash metadata page.
00089  *
00090  * PUBLIC: int CDB___ham_mswap __P((void *));
00091  */
00092 int
00093 CDB___ham_mswap(pg)
00094 void *pg;
00095 {
00096 u_int8_t *p;
00097 int i;
00098 
00099 CDB___db_metaswap(pg);
00100 
00101 p = (u_int8_t *)pg + sizeof(DBMETA);
00102 
00103 SWAP32(p); /* max_bucket */
00104 SWAP32(p); /* high_mask */
00105 SWAP32(p); /* low_mask */
00106 SWAP32(p); /* ffactor */
00107 SWAP32(p); /* nelem */
00108 SWAP32(p); /* h_charkey */
00109 for (i = 0; i < NCACHED; ++i)
00110 SWAP32(p); /* spares */
00111 return (0);
00112 }