db release 1.85

1 files changed, 116 insertions, 86 deletions

diff --git a/lib/libc/db/btree/btree.h b/lib/libc/db/btree/btree.h
index 747ed93638e..d2bb945a1c3 100644
--- a/lib/libc/db/btree/btree.h
+++ b/lib/libc/db/btree/btree.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: btree.h,v 1.8 1995/02/27 13:21:08 cgd Exp $	*/
+/*	$NetBSD: btree.h,v 1.9 1996/05/03 21:51:00 cgd Exp $	*/
 
 /*-
  * Copyright (c) 1991, 1993, 1994
@@ -35,9 +35,14 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)btree.h	8.6 (Berkeley) 5/31/94
+ *	@(#)btree.h	8.11 (Berkeley) 8/17/94
  */
 
+/* Macros to set/clear/test flags. */
+#define	F_SET(p, f)	(p)->flags |= (f)
+#define	F_CLR(p, f)	(p)->flags &= ~(f)
+#define	F_ISSET(p, f)	((p)->flags & (f))
+
 #include <mpool.h>
 
 #define	DEFMINKEYPAGE	(2)		/* Minimum keys per page */
@@ -81,8 +86,9 @@ typedef struct _page {
 } PAGE;
 
 /* First and next index. */
-#define	BTDATAOFF	(sizeof(pgno_t) + sizeof(pgno_t) + sizeof(pgno_t) + \
-			    sizeof(u_int32_t) + sizeof(indx_t) + sizeof(indx_t))
+#define	BTDATAOFF							\
+	(sizeof(pgno_t) + sizeof(pgno_t) + sizeof(pgno_t) +		\
+	    sizeof(u_int32_t) + sizeof(indx_t) + sizeof(indx_t))
 #define	NEXTINDEX(p)	(((p)->lower - BTDATAOFF) / sizeof(indx_t))
 
 /*
@@ -101,8 +107,7 @@ typedef struct _page {
  * be manipulated without copying.  (This presumes that 32 bit items can be
  * manipulated on this system.)
  */
-#define	LALIGN(n) \
-	(((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1))
+#define	LALIGN(n)	(((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1))
 #define	NOVFLSIZE	(sizeof(pgno_t) + sizeof(u_int32_t))
 
 /*
@@ -124,11 +129,11 @@ typedef struct _binternal {
 } BINTERNAL;
 
 /* Get the page's BINTERNAL structure at index indx. */
-#define	GETBINTERNAL(pg, indx) \
+#define	GETBINTERNAL(pg, indx)						\
 	((BINTERNAL *)((char *)(pg) + (pg)->linp[indx]))
 
 /* Get the number of bytes in the entry. */
-#define NBINTERNAL(len) \
+#define NBINTERNAL(len)							\
 	LALIGN(sizeof(u_int32_t) + sizeof(pgno_t) + sizeof(u_char) + (len))
 
 /* Copy a BINTERNAL entry to the page. */
@@ -151,18 +156,18 @@ typedef struct _rinternal {
 } RINTERNAL;
 
 /* Get the page's RINTERNAL structure at index indx. */
-#define	GETRINTERNAL(pg, indx) \
+#define	GETRINTERNAL(pg, indx)						\
 	((RINTERNAL *)((char *)(pg) + (pg)->linp[indx]))
 
 /* Get the number of bytes in the entry. */
-#define NRINTERNAL \
+#define NRINTERNAL							\
 	LALIGN(sizeof(recno_t) + sizeof(pgno_t))
 
 /* Copy a RINTERAL entry to the page. */
-#define	WR_RINTERNAL(p, nrecs, pgno) { \
-	*(recno_t *)p = nrecs; \
-	p += sizeof(recno_t); \
-	*(pgno_t *)p = pgno; \
+#define	WR_RINTERNAL(p, nrecs, pgno) {					\
+	*(recno_t *)p = nrecs;						\
+	p += sizeof(recno_t);						\
+	*(pgno_t *)p = pgno;						\
 }
 
 /* For the btree leaf pages, the item is a key and data pair. */
@@ -174,15 +179,15 @@ typedef struct _bleaf {
 } BLEAF;
 
 /* Get the page's BLEAF structure at index indx. */
-#define	GETBLEAF(pg, indx) \
+#define	GETBLEAF(pg, indx)						\
 	((BLEAF *)((char *)(pg) + (pg)->linp[indx]))
 
 /* Get the number of bytes in the entry. */
 #define NBLEAF(p)	NBLEAFDBT((p)->ksize, (p)->dsize)
 
 /* Get the number of bytes in the user's key/data pair. */
-#define NBLEAFDBT(ksize, dsize) \
-	LALIGN(sizeof(u_int32_t) + sizeof(u_int32_t) + sizeof(u_char) + \
+#define NBLEAFDBT(ksize, dsize)						\
+	LALIGN(sizeof(u_int32_t) + sizeof(u_int32_t) + sizeof(u_char) +	\
 	    (ksize) + (dsize))
 
 /* Copy a BLEAF entry to the page. */
@@ -206,14 +211,14 @@ typedef struct _rleaf {
 } RLEAF;
 
 /* Get the page's RLEAF structure at index indx. */
-#define	GETRLEAF(pg, indx) \
+#define	GETRLEAF(pg, indx)						\
 	((RLEAF *)((char *)(pg) + (pg)->linp[indx]))
 
 /* Get the number of bytes in the entry. */
 #define NRLEAF(p)	NRLEAFDBT((p)->dsize)
 
 /* Get the number of bytes from the user's data. */
-#define	NRLEAFDBT(dsize) \
+#define	NRLEAFDBT(dsize)						\
 	LALIGN(sizeof(u_int32_t) + sizeof(u_char) + (dsize))
 
 /* Copy a RLEAF entry to the page. */
@@ -234,12 +239,6 @@ typedef struct _rleaf {
  * record less than key in the tree so that descents work.  Leaf page searches
  * must find the smallest record greater than key so that the returned index
  * is the record's correct position for insertion.
- *
- * One comment about cursors.  The cursor key is never removed from the tree,
- * even if deleted.  This is because it is quite difficult to decide where the
- * cursor should be when other keys have been inserted/deleted in the tree;
- * duplicate keys make it impossible.  This scheme does require extra work
- * though, to make sure that we don't perform an operation on a deleted key.
  */
 typedef struct _epgno {
 	pgno_t	pgno;			/* the page number */
@@ -252,53 +251,90 @@ typedef struct _epg {
 } EPG;
 
 /*
- * The metadata of the tree.  The m_nrecs field is used only by the RECNO code.
+ * About cursors.  The cursor (and the page that contained the key/data pair
+ * that it referenced) can be deleted, which makes things a bit tricky.  If
+ * there are no duplicates of the cursor key in the tree (i.e. B_NODUPS is set
+ * or there simply aren't any duplicates of the key) we copy the key that it
+ * referenced when it's deleted, and reacquire a new cursor key if the cursor
+ * is used again.  If there are duplicates keys, we move to the next/previous
+ * key, and set a flag so that we know what happened.  NOTE: if duplicate (to
+ * the cursor) keys are added to the tree during this process, it is undefined
+ * if they will be returned or not in a cursor scan.
+ *
+ * The flags determine the possible states of the cursor:
+ *
+ * CURS_INIT	The cursor references *something*.
+ * CURS_ACQUIRE	The cursor was deleted, and a key has been saved so that
+ *		we can reacquire the right position in the tree.
+ * CURS_AFTER, CURS_BEFORE
+ *		The cursor was deleted, and now references a key/data pair
+ *		that has not yet been returned, either before or after the
+ *		deleted key/data pair.
+ * XXX
+ * This structure is broken out so that we can eventually offer multiple
+ * cursors as part of the DB interface.
+ */
+typedef struct _cursor {
+	EPGNO	 pg;			/* B: Saved tree reference. */
+	DBT	 key;			/* B: Saved key, or key.data == NULL. */
+	recno_t	 rcursor;		/* R: recno cursor (1-based) */
+
+#define	CURS_ACQUIRE	0x01		/*  B: Cursor needs to be reacquired. */
+#define	CURS_AFTER	0x02		/*  B: Unreturned cursor after key. */
+#define	CURS_BEFORE	0x04		/*  B: Unreturned cursor before key. */
+#define	CURS_INIT	0x08		/* RB: Cursor initialized. */
+	u_int8_t flags;
+} CURSOR;
+
+/*
+ * The metadata of the tree.  The nrecs field is used only by the RECNO code.
  * This is because the btree doesn't really need it and it requires that every
  * put or delete call modify the metadata.
  */
 typedef struct _btmeta {
-	u_int32_t	m_magic;	/* magic number */
-	u_int32_t	m_version;	/* version */
-	u_int32_t	m_psize;	/* page size */
-	u_int32_t	m_free;		/* page number of first free page */
-	u_int32_t	m_nrecs;	/* R: number of records */
+	u_int32_t	magic;		/* magic number */
+	u_int32_t	version;	/* version */
+	u_int32_t	psize;		/* page size */
+	u_int32_t	free;		/* page number of first free page */
+	u_int32_t	nrecs;		/* R: number of records */
+
 #define	SAVEMETA	(B_NODUPS | R_RECNO)
-	u_int32_t	m_flags;	/* bt_flags & SAVEMETA */
-	u_int32_t	m_unused;	/* unused */
+	u_int32_t	flags;		/* bt_flags & SAVEMETA */
 } BTMETA;
 
 /* The in-memory btree/recno data structure. */
 typedef struct _btree {
-	MPOOL	*bt_mp;			/* memory pool cookie */
+	MPOOL	 *bt_mp;		/* memory pool cookie */
 
-	DB	*bt_dbp;		/* pointer to enclosing DB */
+	DB	 *bt_dbp;		/* pointer to enclosing DB */
 
-	EPG	bt_cur;			/* current (pinned) page */
-	PAGE	*bt_pinned;		/* page pinned across calls */
+	EPG	  bt_cur;		/* current (pinned) page */
+	PAGE	 *bt_pinned;		/* page pinned across calls */
 
-	EPGNO	bt_bcursor;		/* B: btree cursor */
-	recno_t	bt_rcursor;		/* R: recno cursor (1-based) */
+	CURSOR	  bt_cursor;		/* cursor */
 
-#define	BT_POP(t)	(t->bt_sp ? t->bt_stack + --t->bt_sp : NULL)
-#define	BT_CLR(t)	(t->bt_sp = 0)
-	EPGNO	*bt_stack;		/* stack of parent pages */
-	u_int	bt_sp;			/* current stack pointer */
-	u_int	bt_maxstack;		/* largest stack */
+#define	BT_PUSH(t, p, i) {						\
+	t->bt_sp->pgno = p; 						\
+	t->bt_sp->index = i; 						\
+	++t->bt_sp;							\
+}
+#define	BT_POP(t)	(t->bt_sp == t->bt_stack ? NULL : --t->bt_sp)
+#define	BT_CLR(t)	(t->bt_sp = t->bt_stack)
+	EPGNO	  bt_stack[50];		/* stack of parent pages */
+	EPGNO	 *bt_sp;		/* current stack pointer */
 
-	char	*bt_kbuf;		/* key buffer */
-	size_t	bt_kbufsz;		/* key buffer size */
-	char	*bt_dbuf;		/* data buffer */
-	size_t	bt_dbufsz;		/* data buffer size */
+	DBT	  bt_rkey;		/* returned key */
+	DBT	  bt_rdata;		/* returned data */
 
-	int	bt_fd;			/* tree file descriptor */
+	int	  bt_fd;		/* tree file descriptor */
 
-	pgno_t	bt_free;		/* next free page */
+	pgno_t	  bt_free;		/* next free page */
 	u_int32_t bt_psize;		/* page size */
-	indx_t	bt_ovflsize;		/* cut-off for key/data overflow */
-	int	bt_lorder;		/* byte order */
+	indx_t	  bt_ovflsize;		/* cut-off for key/data overflow */
+	int	  bt_lorder;		/* byte order */
 					/* sorted order */
 	enum { NOT, BACK, FORWARD } bt_order;
-	EPGNO	bt_last;		/* last insert */
+	EPGNO	  bt_last;		/* last insert */
 
 					/* B: key comparison function */
 	int	(*bt_cmp) __P((const DBT *, const DBT *));
@@ -307,49 +343,43 @@ typedef struct _btree {
 					/* R: recno input function */
 	int	(*bt_irec) __P((struct _btree *, recno_t));
 
-	FILE	*bt_rfp;		/* R: record FILE pointer */
-	int	bt_rfd;			/* R: record file descriptor */
+	FILE	 *bt_rfp;		/* R: record FILE pointer */
+	int	  bt_rfd;		/* R: record file descriptor */
 
-	caddr_t	bt_cmap;		/* R: current point in mapped space */
-	caddr_t	bt_smap;		/* R: start of mapped space */
-	caddr_t bt_emap;		/* R: end of mapped space */
-	size_t	bt_msize;		/* R: size of mapped region. */
+	caddr_t	  bt_cmap;		/* R: current point in mapped space */
+	caddr_t	  bt_smap;		/* R: start of mapped space */
+	caddr_t   bt_emap;		/* R: end of mapped space */
+	size_t	  bt_msize;		/* R: size of mapped region. */
 
-	recno_t	bt_nrecs;		/* R: number of records */
-	size_t	bt_reclen;		/* R: fixed record length */
-	u_char	bt_bval;		/* R: delimiting byte/pad character */
+	recno_t	  bt_nrecs;		/* R: number of records */
+	size_t	  bt_reclen;		/* R: fixed record length */
+	u_char	  bt_bval;		/* R: delimiting byte/pad character */
 
 /*
  * NB:
  * B_NODUPS and R_RECNO are stored on disk, and may not be changed.
  */
-#define	B_DELCRSR	0x00001		/* cursor has been deleted */
-#define	B_INMEM		0x00002		/* in-memory tree */
-#define	B_METADIRTY	0x00004		/* need to write metadata */
-#define	B_MODIFIED	0x00008		/* tree modified */
-#define	B_NEEDSWAP	0x00010		/* if byte order requires swapping */
+#define	B_INMEM		0x00001		/* in-memory tree */
+#define	B_METADIRTY	0x00002		/* need to write metadata */
+#define	B_MODIFIED	0x00004		/* tree modified */
+#define	B_NEEDSWAP	0x00008		/* if byte order requires swapping */
+#define	B_RDONLY	0x00010		/* read-only tree */
+
 #define	B_NODUPS	0x00020		/* no duplicate keys permitted */
-#define	B_RDONLY	0x00040		/* read-only tree */
 #define	R_RECNO		0x00080		/* record oriented tree */
-#define	B_SEQINIT	0x00100		/* sequential scan initialized */
-
-#define	R_CLOSEFP	0x00200		/* opened a file pointer */
-#define	R_EOF		0x00400		/* end of input file reached. */
-#define	R_FIXLEN	0x00800		/* fixed length records */
-#define	R_MEMMAPPED	0x01000		/* memory mapped file. */
-#define	R_INMEM		0x02000		/* in-memory file */
-#define	R_MODIFIED	0x04000		/* modified file */
-#define	R_RDONLY	0x08000		/* read-only file */
 
-#define	B_DB_LOCK	0x10000		/* DB_LOCK specified. */
-#define	B_DB_SHMEM	0x20000		/* DB_SHMEM specified. */
-#define	B_DB_TXN	0x40000		/* DB_TXN specified. */
-
-	u_int32_t	bt_flags;	/* btree state */
+#define	R_CLOSEFP	0x00040		/* opened a file pointer */
+#define	R_EOF		0x00100		/* end of input file reached. */
+#define	R_FIXLEN	0x00200		/* fixed length records */
+#define	R_MEMMAPPED	0x00400		/* memory mapped file. */
+#define	R_INMEM		0x00800		/* in-memory file */
+#define	R_MODIFIED	0x01000		/* modified file */
+#define	R_RDONLY	0x02000		/* read-only file */
+
+#define	B_DB_LOCK	0x04000		/* DB_LOCK specified. */
+#define	B_DB_SHMEM	0x08000		/* DB_SHMEM specified. */
+#define	B_DB_TXN	0x10000		/* DB_TXN specified. */
+	u_int32_t flags;
 } BTREE;
 
-#define	SET(t, f)	((t)->bt_flags |= (f))
-#define	CLR(t, f)	((t)->bt_flags &= ~(f))
-#define	ISSET(t, f)	((t)->bt_flags & (f))
-
 #include "extern.h"