db_page.h

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

/*
 * Initialize a page.
 *
 * !!!
 * Don't modify the page's LSN, code depends on it being unchanged after a
 * P_INIT call.
 */
#define	P_INIT(pg, pg_size, n, pg_prev, pg_next, btl, pg_type) do {	\
	PGNO(pg) = n;							\
	PREV_PGNO(pg) = pg_prev;					\
	NEXT_PGNO(pg) = pg_next;					\
	NUM_ENT(pg) = 0;						\
	HOFFSET(pg) = pg_size;						\
	LEVEL(pg) = btl;						\
	TYPE(pg) = pg_type;						\
} while (0)

/* Page header length (offset to first index). */
#define	P_OVERHEAD(dbp)	P_TO_UINT16(P_INP(dbp, 0))

/* First free byte. */
#define	LOFFSET(dbp, pg)						\
    (P_OVERHEAD(dbp) + NUM_ENT(pg) * sizeof(db_indx_t))

/* Free space on a regular page. */
#define	P_FREESPACE(dbp, pg)	(HOFFSET(pg) - LOFFSET(dbp, pg))

/* Get a pointer to the bytes at a specific index. */
#define	P_ENTRY(dbp, pg, indx)	((u_int8_t *)pg + P_INP(dbp, pg)[indx])

/************************************************************************
 OVERFLOW PAGE LAYOUT
 ************************************************************************/

/*
 * Overflow items are referenced by HOFFPAGE and BOVERFLOW structures, which
 * store a page number (the first page of the overflow item) and a length
 * (the total length of the overflow item).  The overflow item consists of
 * some number of overflow pages, linked by the next_pgno field of the page.
 * A next_pgno field of PGNO_INVALID flags the end of the overflow item.
 *
 * Overflow page overloads:
 *	The amount of overflow data stored on each page is stored in the
 *	hf_offset field.
 *
 *	The implementation reference counts overflow items as it's possible
 *	for them to be promoted onto btree internal pages.  The reference
 *	count is stored in the entries field.
 */
#define	OV_LEN(p)	(((PAGE *)p)->hf_offset)
#define	OV_REF(p)	(((PAGE *)p)->entries)

/* Maximum number of bytes that you can put on an overflow page. */
#define	P_MAXSPACE(dbp, psize)	((psize) - P_OVERHEAD(dbp))

/* Free space on an overflow page. */
#define	P_OVFLSPACE(dbp, psize, pg)	(P_MAXSPACE(dbp, psize) - HOFFSET(pg))

/************************************************************************
 HASH PAGE LAYOUT
 ************************************************************************/

/* Each index references a group of bytes on the page. */
#define	H_KEYDATA	1	/* Key/data item. */
#define	H_DUPLICATE	2	/* Duplicate key/data item. */
#define	H_OFFPAGE	3	/* Overflow key/data item. */
#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(dbp, pg, indx)	(*P_ENTRY(dbp, pg, indx))

/*
 * The first and second types are H_KEYDATA and H_DUPLICATE, represented
 * by the HKEYDATA structure:
 *
 *	+-----------------------------------+
 *	|    type   | key/data ...          |
 *	+-----------------------------------+
 *
 * For duplicates, the data field encodes duplicate elements in the data
 * field:
 *
 *	+---------------------------------------------------------------+
 *	|    type   | len1 | element1 | len1 | len2 | element2 | len2   |
 *	+---------------------------------------------------------------+
 *
 * Thus, by keeping track of the offset in the element, we can do both
 * backward and forward traversal.
 */
typedef struct _hkeydata {
	u_int8_t  type;		/*    00: Page type. */
	u_int8_t  data[1];	/* Variable length key/data item. */
} HKEYDATA;
#define	HKEYDATA_DATA(p)	(((u_int8_t *)p) + SSZA(HKEYDATA, data))

/*
 * The length of any HKEYDATA item. Note that indx is an element index,
 * not a PAIR index.
 */
#define	LEN_HITEM(dbp, pg, pgsize, indx)				\
	(((indx) == 0 ? pgsize :					\
	(P_INP(dbp, pg)[indx - 1])) - (P_INP(dbp, pg)[indx]))

#define	LEN_HKEYDATA(dbp, pg, psize, indx)				\
	(db_indx_t)(LEN_HITEM(dbp, pg, psize, indx) - HKEYDATA_SIZE(0))

/*
 * Page space required to add a new HKEYDATA item to the page, with and
 * without the index value.
 */
#define	HKEYDATA_SIZE(len)						\
	((len) + SSZA(HKEYDATA, data))
#define	HKEYDATA_PSIZE(len)						\
	(HKEYDATA_SIZE(len) + sizeof(db_indx_t))

/* Put a HKEYDATA item at the location referenced by a page entry. */
#define	PUT_HKEYDATA(pe, kd, len, type) {				\
	((HKEYDATA *)pe)->type = type;					\
	memcpy((u_int8_t *)pe + sizeof(u_int8_t), kd, len);		\
}

/*
 * Macros the describe the page layout in terms of key-data pairs.
 */
#define	H_NUMPAIRS(pg)			(NUM_ENT(pg) / 2)
#define	H_KEYINDEX(indx)		(indx)
#define	H_DATAINDEX(indx)		((indx) + 1)
#define	H_PAIRKEY(dbp, pg, indx)	P_ENTRY(dbp, pg, H_KEYINDEX(indx))
#define	H_PAIRDATA(dbp, pg, indx)	P_ENTRY(dbp, pg, H_DATAINDEX(indx))
#define	H_PAIRSIZE(dbp, pg, psize, indx)				\
	(LEN_HITEM(dbp, pg, psize, H_KEYINDEX(indx)) +			\
	LEN_HITEM(dbp, pg, psize, H_DATAINDEX(indx)))
#define	LEN_HDATA(dbp, p, psize, indx)					\
    LEN_HKEYDATA(dbp, p, psize, H_DATAINDEX(indx))
#define	LEN_HKEY(dbp, p, psize, indx)					\
    LEN_HKEYDATA(dbp, p, psize, H_KEYINDEX(indx))

/*
 * The third type is the H_OFFPAGE, represented by the HOFFPAGE structure:
 */
typedef struct _hoffpage {
	u_int8_t  type;		/*    00: Page type and delete flag. */
	u_int8_t  unused[3];	/* 01-03: Padding, unused. */
	db_pgno_t pgno;		/* 04-07: Offpage page number. */
	u_int32_t tlen;		/* 08-11: Total length of item. */
} HOFFPAGE;

#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
 * without the index value.
 */
#define	HOFFPAGE_SIZE		(sizeof(HOFFPAGE))
#define	HOFFPAGE_PSIZE		(HOFFPAGE_SIZE + sizeof(db_indx_t))

/*
 * The fourth type is H_OFFDUP represented by the HOFFDUP structure:
 */
typedef struct _hoffdup {
	u_int8_t  type;		/*    00: Page type and delete flag. */
	u_int8_t  unused[3];	/* 01-03: Padding, unused. */
	db_pgno_t pgno;		/* 04-07: Offpage page number. */
} HOFFDUP;
#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
 * without the index value.
 */
#define	HOFFDUP_SIZE		(sizeof(HOFFDUP))

/************************************************************************
 BTREE PAGE LAYOUT
 ************************************************************************/

/* Each index references a group of bytes on the page. */
#define	B_KEYDATA	1	/* Key/data item. */
#define	B_DUPLICATE	2	/* Duplicate key/data item. */
#define	B_OVERFLOW	3	/* Overflow key/data item. */

/*
 * We have to store a deleted entry flag in the page.   The reason is complex,
 * but the simple version is that we can't delete on-page items referenced by
 * a cursor -- the return order of subsequent insertions might be wrong.  The
 * delete flag is an overload of the top bit of the type byte.
 */
#define	B_DELETE	(0x80)
#define	B_DCLR(t)	(t) &= ~B_DELETE
#define	B_DSET(t)	(t) |= B_DELETE
#define	B_DISSET(t)	((t) & B_DELETE)

#define	B_TYPE(t)	((t) & ~B_DELETE)
#define	B_TSET(t, type, deleted) {					\
	(t) = (type);							\
	if (deleted)							\
		B_DSET(t);						\
}

/*
 * The first type is B_KEYDATA, represented by the BKEYDATA structure:
 */
typedef struct _bkeydata {
	db_indx_t len;		/* 00-01: Key/data item length. */
	u_int8_t  type;		/*    02: Page type AND DELETE FLAG. */
	u_int8_t  data[1];	/* Variable length key/data item. */
} BKEYDATA;

/* Get a BKEYDATA item for a specific index. */
#define	GET_BKEYDATA(dbp, pg, indx)					\
	((BKEYDATA *)P_ENTRY(dbp, pg, indx))

/*
 * Page space required to add a new BKEYDATA item to the page, with and
 * without the index value.
 */
#define	BKEYDATA_SIZE(len)						\
	ALIGN((len) + SSZA(BKEYDATA, data), sizeof(u_int32_t))
#define	BKEYDATA_PSIZE(len)						\
	(BKEYDATA_SIZE(len) + sizeof(db_indx_t))

/*
 * The second and third types are B_DUPLICATE and B_OVERFLOW, represented
 * by the BOVERFLOW structure.
 */
typedef struct _boverflow {
	db_indx_t unused1;	/* 00-01: Padding, unused. */
	u_int8_t  type;		/*    02: Page type AND DELETE FLAG. */
	u_int8_t  unused2;	/*    03: Padding, unused. */
	db_pgno_t pgno;		/* 04-07: Next page number. */
	u_int32_t tlen;		/* 08-11: Total length of item. */
} BOVERFLOW;

/* Get a BOVERFLOW item for a specific index. */
#define	GET_BOVERFLOW(dbp, pg, indx)					\
	((BOVERFLOW *)P_ENTRY(dbp, pg, indx))

/*
 * Page space required to add a new BOVERFLOW item to the page, with and
 * without the index value.  The (u_int16_t) cast avoids warnings: ALIGN
 * casts to db_align_t, the cast converts it to a small integral type so
 * we don't get complaints when we assign the final result to an integral
 * type smaller than db_align_t.
 */
#define	BOVERFLOW_SIZE							\
	((u_int16_t)ALIGN(sizeof(BOVERFLOW), sizeof(u_int32_t)))
#define	BOVERFLOW_PSIZE							\
	(BOVERFLOW_SIZE + sizeof(db_indx_t))

/*
 * Btree leaf and hash page layouts group indices in sets of two, one for the
 * key and one for the data.  Everything else does it in sets of one to save
 * space.  Use the following macros so that it's real obvious what's going on.
 */
#define	O_INDX	1
#define	P_INDX	2

/************************************************************************
 BTREE INTERNAL PAGE LAYOUT
 ************************************************************************/

/*
 * Btree internal entry.
 */
typedef struct _binternal {
	db_indx_t  len;		/* 00-01: Key/data item length. */
	u_int8_t   type;	/*    02: Page type AND DELETE FLAG. */
	u_int8_t   unused;	/*    03: Padding, unused. */
	db_pgno_t  pgno;	/* 04-07: Page number of referenced page. */
	db_recno_t nrecs;	/* 08-11: Subtree record count. */
	u_int8_t   data[1];	/* Variable length key item. */
} BINTERNAL;

/* Get a BINTERNAL item for a specific index. */
#define	GET_BINTERNAL(dbp, pg, indx)					\
	((BINTERNAL *)P_ENTRY(dbp, pg, indx))

/*
 * Page space required to add a new BINTERNAL item to the page, with and
 * without the index value.
 */
#define	BINTERNAL_SIZE(len)						\
	ALIGN((len) + SSZA(BINTERNAL, data), sizeof(u_int32_t))
#define	BINTERNAL_PSIZE(len)						\
	(BINTERNAL_SIZE(len) + sizeof(db_indx_t))

/************************************************************************
 RECNO INTERNAL PAGE LAYOUT
 ************************************************************************/

/*
 * The recno internal entry.
 */
typedef struct _rinternal {
	db_pgno_t  pgno;	/* 00-03: Page number of referenced page. */
	db_recno_t nrecs;	/* 04-07: Subtree record count. */
} RINTERNAL;

/* Get a RINTERNAL item for a specific index. */
#define	GET_RINTERNAL(dbp, pg, indx)					\
	((RINTERNAL *)P_ENTRY(dbp, pg, indx))

/*
 * Page space required to add a new RINTERNAL item to the page, with and
 * without the index value.
 */
#define	RINTERNAL_SIZE							\
	ALIGN(sizeof(RINTERNAL), sizeof(u_int32_t))
#define	RINTERNAL_PSIZE							\
	(RINTERNAL_SIZE + sizeof(db_indx_t))

#if defined(__cplusplus)
}
#endif

#endif /* !_DB_PAGE_H_ */