diff options
Diffstat (limited to 'db2/include/db_page.h')
| -rw-r--r-- | db2/include/db_page.h | 32 |
1 files changed, 18 insertions, 14 deletions
diff --git a/db2/include/db_page.h b/db2/include/db_page.h index cde7ff9f2e..30f6072fc3 100644 --- a/db2/include/db_page.h +++ b/db2/include/db_page.h @@ -4,7 +4,7 @@ * Copyright (c) 1996, 1997 * Sleepycat Software. All rights reserved. * - * @(#)db_page.h 10.11 (Sleepycat) 9/3/97 + * @(#)db_page.h 10.13 (Sleepycat) 9/24/97 */ #ifndef _DB_PAGE_H_ @@ -273,6 +273,17 @@ typedef struct _db_page { #define H_OFFDUP 4 /* Overflow page of duplicates. */ /* + * !!! + * Items on hash pages are (potentially) unaligned, so we can never cast the + * (page + offset) pointer to an HKEYDATA, HOFFPAGE or HOFFDUP structure, as + * we do with B+tree on-page structures. Because we frequently want the type + * field, it requires no alignment, and it's in the same location in all three + * structures, there's a pair of macros. + */ +#define HPAGE_PTYPE(p) (*(u_int8_t *)p) +#define HPAGE_TYPE(pg, indx) (*P_ENTRY(pg, indx)) + +/* * The first and second types are H_KEYDATA and H_DUPLICATE, represented * by the HKEYDATA structure: * @@ -294,10 +305,7 @@ typedef struct _hkeydata { u_int8_t type; /* 00: Page type. */ u_int8_t data[1]; /* Variable length key/data item. */ } HKEYDATA; - -/* Get a HKEYDATA item for a specific index. */ -#define GET_HKEYDATA(pg, indx) \ - ((HKEYDATA *)P_ENTRY(pg, indx)) +#define HKEYDATA_DATA(p) (((u_int8_t *)p) + SSZA(HKEYDATA, data)) /* * The length of any HKEYDATA item. Note that indx is an element index, @@ -333,8 +341,8 @@ typedef struct _hkeydata { #define H_NUMPAIRS(pg) (NUM_ENT(pg) / 2) #define H_KEYINDEX(pindx) (2 * (pindx)) #define H_DATAINDEX(pindx) ((2 * (pindx)) + 1) -#define H_PAIRKEY(pg, pindx) GET_HKEYDATA(pg, H_KEYINDEX(pindx)) -#define H_PAIRDATA(pg, pindx) GET_HKEYDATA(pg, H_DATAINDEX(pindx)) +#define H_PAIRKEY(pg, pindx) P_ENTRY(pg, H_KEYINDEX(pindx)) +#define H_PAIRDATA(pg, pindx) P_ENTRY(pg, H_DATAINDEX(pindx)) #define H_PAIRSIZE(pg, psize, pindx) \ (LEN_HITEM(pg, psize, H_KEYINDEX(pindx)) + \ LEN_HITEM(pg, psize, H_DATAINDEX(pindx))) @@ -355,9 +363,8 @@ typedef struct _hoffpage { u_int32_t tlen; /* 08-11: Total length of item. */ } HOFFPAGE; -/* Get a HOFFPAGE item for a specific index. */ -#define GET_HOFFPAGE(pg, indx) \ - ((HOFFPAGE *)P_ENTRY(pg, indx)) +#define HOFFPAGE_PGNO(p) (((u_int8_t *)p) + SSZ(HOFFPAGE, pgno)) +#define HOFFPAGE_TLEN(p) (((u_int8_t *)p) + SSZ(HOFFPAGE, tlen)) /* * Page space required to add a new HOFFPAGE item to the page, with and @@ -378,10 +385,7 @@ typedef struct _hoffdup { u_int8_t unused[3]; /* 01-03: Padding, unused. */ db_pgno_t pgno; /* 04-07: Offpage page number. */ } HOFFDUP; - -/* Get a HOFFDUP item for a specific index. */ -#define GET_HOFFDUP(pg, indx) \ - ((HOFFDUP *)P_ENTRY(pg, indx)) +#define HOFFDUP_PGNO(p) (((u_int8_t *)p) + SSZ(HOFFDUP, pgno)) /* * Page space required to add a new HOFFDUP item to the page, with and |