Commit dec34b02 authored by cvs2hg's avatar cvs2hg

fixup commit for tag 'JSS_3_4_2_BETA1'

parent 8a9fae6c

Too many changes to show.

To preserve performance only 274 of 274+ files are displayed.

#
# The contents of this file are subject to the Netscape Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/NPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is mozilla.org code.
#
# The Initial Developer of the Original Code is Netscape
# Communications Corporation. Portions created by Netscape are
# Copyright (C) 1998 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s):
#
DEPTH = ..
topsrcdir = @top_srcdir@
srcdir = @srcdir@
VPATH = @srcdir@
include $(DEPTH)/config/autoconf.mk
MODULE = dbm
DIRS = include src
ifdef ENABLE_TESTS
DIRS += tests
endif
include $(topsrcdir)/config/rules.mk
#
# The contents of this file are subject to the Netscape Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/NPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is mozilla.org code.
#
# The Initial Developer of the Original Code is Netscape
# Communications Corporation. Portions created by Netscape are
# Copyright (C) 1998 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s):
#
DEPTH = ../..
topsrcdir = @top_srcdir@
srcdir = @srcdir@
VPATH = @srcdir@
include $(DEPTH)/config/autoconf.mk
MODULE = dbm
EXPORTS = \
nsres.h \
cdefs.h \
mcom_db.h \
ncompat.h \
winfile.h \
$(NULL)
EXPORTS := $(addprefix $(srcdir)/, $(EXPORTS))
PRIVATE_EXPORTS = \
hsearch.h \
page.h \
extern.h \
ndbm.h \
queue.h \
hash.h \
mpool.h \
search.h \
$(NULL)
PRIVATE_EXPORTS := $(addprefix $(srcdir)/, $(PRIVATE_EXPORTS))
include $(topsrcdir)/config/rules.mk
# The contents of this file are subject to the Netscape Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/NPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is mozilla.org code.
#
# The Initial Developer of the Original Code is Netscape
# Communications Corporation. Portions created by Netscape are
# Copyright (C) 1998 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s):
#//------------------------------------------------------------------------
#//
#// Makefile to build the cert library
#//
#//------------------------------------------------------------------------
!if "$(MOZ_BITS)" == "16"
!ifndef MOZ_DEBUG
OPTIMIZER=-Os -UDEBUG -DNDEBUG
!endif
!endif
#//------------------------------------------------------------------------
#//
#// Specify the depth of the current directory relative to the
#// root of NS
#//
#//------------------------------------------------------------------------
DEPTH= ..\..
!ifndef MAKE_OBJ_TYPE
MAKE_OBJ_TYPE=EXE
!endif
#//------------------------------------------------------------------------
#//
#// install headers
#//
#//------------------------------------------------------------------------
EXPORTS=nsres.h cdefs.h mcom_db.h ncompat.h winfile.h
#//------------------------------------------------------------------------
#//
#// Include the common makefile rules
#//
#//------------------------------------------------------------------------
include <$(DEPTH)/config/rules.mak>
CFLAGS = $(CFLAGS) -DMOZILLA_CLIENT
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: NPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Netscape Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the NPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the NPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Berkeley Software Design, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)cdefs.h 8.7 (Berkeley) 1/21/94
*/
#ifndef _CDEFS_H_
#define _CDEFS_H_
#if defined(__cplusplus)
#define __BEGIN_DECLS extern "C" {
#define __END_DECLS }
#else
#define __BEGIN_DECLS
#define __END_DECLS
#endif
/*
* The __CONCAT macro is used to concatenate parts of symbol names, e.g.
* with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
* The __CONCAT macro is a bit tricky -- make sure you don't put spaces
* in between its arguments. __CONCAT can also concatenate double-quoted
* strings produced by the __STRING macro, but this only works with ANSI C.
*/
#if defined(__STDC__) || defined(__cplusplus) || defined(_WINDOWS) || defined(XP_OS2)
#define __P(protos) protos /* full-blown ANSI C */
#define __CONCAT(x,y) x ## y
#define __STRING(x) #x
/* On HP-UX 11.00, <sys/stdsyms.h> defines __const. */
#ifndef __const
#define __const const /* define reserved names to standard */
#endif /* __const */
#define __signed signed
#define __volatile volatile
#ifndef _WINDOWS
#if defined(__cplusplus)
#define __inline inline /* convert to C++ keyword */
#else
#if !defined(__GNUC__) && !defined(__MWERKS__)
#define __inline /* delete GCC keyword */
#endif /* !__GNUC__ */
#endif /* !__cplusplus */
#endif /* !_WINDOWS */
#else /* !(__STDC__ || __cplusplus) */
#define __P(protos) () /* traditional C preprocessor */
#define __CONCAT(x,y) x/**/y
#define __STRING(x) "x"
#ifndef __GNUC__
#define __const /* delete pseudo-ANSI C keywords */
#define __inline
#define __signed
#define __volatile
/*
* In non-ANSI C environments, new programs will want ANSI-only C keywords
* deleted from the program and old programs will want them left alone.
* When using a compiler other than gcc, programs using the ANSI C keywords
* const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
* When using "gcc -traditional", we assume that this is the intent; if
* __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
*/
#ifndef NO_ANSI_KEYWORDS
#define const /* delete ANSI C keywords */
#define inline
#define signed
#define volatile
#endif
#endif /* !__GNUC__ */
#endif /* !(__STDC__ || __cplusplus) */
/*
* GCC1 and some versions of GCC2 declare dead (non-returning) and
* pure (no side effects) functions using "volatile" and "const";
* unfortunately, these then cause warnings under "-ansi -pedantic".
* GCC2 uses a new, peculiar __attribute__((attrs)) style. All of
* these work for GNU C++ (modulo a slight glitch in the C++ grammar
* in the distribution version of 2.5.5).
*/
#if !defined(__GNUC__) || __GNUC__ < 2 || __GNUC_MINOR__ < 5
#define __attribute__(x) /* delete __attribute__ if non-gcc or gcc1 */
#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
#define __dead __volatile
#define __pure __const
#endif
#endif
/* Delete pseudo-keywords wherever they are not available or needed. */
#ifndef __dead
#define __dead
#define __pure
#endif
#endif /* !_CDEFS_H_ */
/*-
* Copyright (c) 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)extern.h 8.4 (Berkeley) 6/16/94
*/
BUFHEAD *__add_ovflpage (HTAB *, BUFHEAD *);
int __addel (HTAB *, BUFHEAD *, const DBT *, const DBT *);
int __big_delete (HTAB *, BUFHEAD *);
int __big_insert (HTAB *, BUFHEAD *, const DBT *, const DBT *);
int __big_keydata (HTAB *, BUFHEAD *, DBT *, DBT *, int);
int __big_return (HTAB *, BUFHEAD *, int, DBT *, int);
int __big_split (HTAB *, BUFHEAD *, BUFHEAD *, BUFHEAD *,
uint32, uint32, SPLIT_RETURN *);
int __buf_free (HTAB *, int, int);
void __buf_init (HTAB *, int);
uint32 __call_hash (HTAB *, char *, size_t);
int __delpair (HTAB *, BUFHEAD *, int);
int __expand_table (HTAB *);
int __find_bigpair (HTAB *, BUFHEAD *, int, char *, int);
uint16 __find_last_page (HTAB *, BUFHEAD **);
void __free_ovflpage (HTAB *, BUFHEAD *);
BUFHEAD *__get_buf (HTAB *, uint32, BUFHEAD *, int);
int __get_page (HTAB *, char *, uint32, int, int, int);
int __ibitmap (HTAB *, int, int, int);
uint32 __log2 (uint32);
int __put_page (HTAB *, char *, uint32, int, int);
void __reclaim_buf (HTAB *, BUFHEAD *);
int __split_page (HTAB *, uint32, uint32);
/* Default hash routine. */
extern uint32 (*__default_hash) (const void *, size_t);
#ifdef HASH_STATISTICS
extern int hash_accesses, hash_collisions, hash_expansions, hash_overflows;
#endif
/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Margo Seltzer.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)hash.h 8.3 (Berkeley) 5/31/94
*/
/* Operations */
#include <stdio.h>
#include "mcom_db.h"
typedef enum {
HASH_GET, HASH_PUT, HASH_PUTNEW, HASH_DELETE, HASH_FIRST, HASH_NEXT
} ACTION;
/* Buffer Management structures */
typedef struct _bufhead BUFHEAD;
struct _bufhead {
BUFHEAD *prev; /* LRU links */
BUFHEAD *next; /* LRU links */
BUFHEAD *ovfl; /* Overflow page buffer header */
uint32 addr; /* Address of this page */
char *page; /* Actual page data */
char is_disk;
char flags;
#define BUF_MOD 0x0001
#define BUF_DISK 0x0002
#define BUF_BUCKET 0x0004
#define BUF_PIN 0x0008
};
#define IS_BUCKET(X) ((X) & BUF_BUCKET)
typedef BUFHEAD **SEGMENT;
typedef int DBFILE_PTR;
#define NO_FILE -1
#ifdef macintosh
#define DBFILE_OPEN(path, flag,mode) open((path), flag)
#define EXISTS(path)
#else
#define DBFILE_OPEN(path, flag,mode) open((path), (flag), (mode))
#endif
/* Hash Table Information */
typedef struct hashhdr { /* Disk resident portion */
int32 magic; /* Magic NO for hash tables */
int32 version; /* Version ID */
uint32 lorder; /* Byte Order */
int32 bsize; /* Bucket/Page Size */
int32 bshift; /* Bucket shift */
int32 dsize; /* Directory Size */
int32 ssize; /* Segment Size */
int32 sshift; /* Segment shift */
int32 ovfl_point; /* Where overflow pages are being
* allocated */
int32 last_freed; /* Last overflow page freed */
int32 max_bucket; /* ID of Maximum bucket in use */
int32 high_mask; /* Mask to modulo into entire table */
int32 low_mask; /* Mask to modulo into lower half of
* table */
int32 ffactor; /* Fill factor */
int32 nkeys; /* Number of keys in hash table */
int32 hdrpages; /* Size of table header */
uint32 h_charkey; /* value of hash(CHARKEY) */
#define NCACHED 32 /* number of bit maps and spare
* points */
int32 spares[NCACHED];/* spare pages for overflow */
uint16 bitmaps[NCACHED]; /* address of overflow page
* bitmaps */
} HASHHDR;
typedef struct htab { /* Memory resident data structure */
HASHHDR hdr; /* Header */
int nsegs; /* Number of allocated segments */
int exsegs; /* Number of extra allocated
* segments */
uint32 /* Hash function */
(*hash)(const void *, size_t);
int flags; /* Flag values */
DBFILE_PTR fp; /* File pointer */
char *filename;
char *tmp_buf; /* Temporary Buffer for BIG data */
char *tmp_key; /* Temporary Buffer for BIG keys */
BUFHEAD *cpage; /* Current page */
int cbucket; /* Current bucket */
int cndx; /* Index of next item on cpage */
int dbmerrno; /* Error Number -- for DBM
* compatability */
int new_file; /* Indicates if fd is backing store
* or no */
int save_file; /* Indicates whether we need to flush
* file at
* exit */
uint32 *mapp[NCACHED]; /* Pointers to page maps */
int nmaps; /* Initial number of bitmaps */
int nbufs; /* Number of buffers left to
* allocate */
BUFHEAD bufhead; /* Header of buffer lru list */
SEGMENT *dir; /* Hash Bucket directory */
off_t file_size; /* in bytes */
char is_temp; /* unlink file on close */
char updateEOF; /* force EOF update on flush */
} HTAB;
/*
* Constants
*/
#define DATABASE_CORRUPTED_ERROR -999 /* big ugly abort, delete database */
#define OLD_MAX_BSIZE 65536 /* 2^16 */
#define MAX_BSIZE 32l*1024l /* 2^15 */
#define MIN_BUFFERS 6
#define MINHDRSIZE 512
#define DEF_BUFSIZE 65536l /* 64 K */
#define DEF_BUCKET_SIZE 4096
#define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */
#define DEF_SEGSIZE 256
#define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */
#define DEF_DIRSIZE 256
#define DEF_FFACTOR 65536l
#define MIN_FFACTOR 4
#define SPLTMAX 8
#define CHARKEY "%$sniglet^&"
#define NUMKEY 1038583l
#define BYTE_SHIFT 3
#define INT_TO_BYTE 2
#define INT_BYTE_SHIFT 5
#define ALL_SET ((uint32)0xFFFFFFFF)
#define ALL_CLEAR 0
#define PTROF(X) ((ptrdiff_t)(X) == BUF_DISK ? 0 : (X))
#define ISDISK(X) ((X) ? ((ptrdiff_t)(X) == BUF_DISK ? BUF_DISK \
: (X)->is_disk) : 0)
#define BITS_PER_MAP 32
/* Given the address of the beginning of a big map, clear/set the nth bit */
#define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1<<((N)%BITS_PER_MAP)))
#define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1<<((N)%BITS_PER_MAP)))
#define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP)))
/* Overflow management */
/*
* Overflow page numbers are allocated per split point. At each doubling of
* the table, we can allocate extra pages. So, an overflow page number has
* the top 5 bits indicate which split point and the lower 11 bits indicate
* which page at that split point is indicated (pages within split points are
* numberered starting with 1).
*/
#define SPLITSHIFT 11
#define SPLITMASK 0x7FF
#define SPLITNUM(N) (((uint32)(N)) >> SPLITSHIFT)
#define OPAGENUM(N) ((N) & SPLITMASK)
#define OADDR_OF(S,O) ((uint32)((uint32)(S) << SPLITSHIFT) + (O))
#define BUCKET_TO_PAGE(B) \
(B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[__log2((uint32)((B)+1))-1] : 0)
#define OADDR_TO_PAGE(B) \
BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B));
/*
* page.h contains a detailed description of the page format.
*
* Normally, keys and data are accessed from offset tables in the top of
* each page which point to the beginning of the key and data. There are
* four flag values which may be stored in these offset tables which indicate
* the following:
*
*
* OVFLPAGE Rather than a key data pair, this pair contains
* the address of an overflow page. The format of
* the pair is:
* OVERFLOW_PAGE_NUMBER OVFLPAGE
*
* PARTIAL_KEY This must be the first key/data pair on a page
* and implies that page contains only a partial key.
* That is, the key is too big to fit on a single page
* so it starts on this page and continues on the next.
* The format of the page is:
* KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE
*
* KEY_OFF -- offset of the beginning of the key
* PARTIAL_KEY -- 1
* OVFL_PAGENO - page number of the next overflow page
* OVFLPAGE -- 0
*
* FULL_KEY This must be the first key/data pair on the page. It
* is used in two cases.
*
* Case 1:
* There is a complete key on the page but no data
* (because it wouldn't fit). The next page contains
* the data.
*
* Page format it:
* KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE
*
* KEY_OFF -- offset of the beginning of the key
* FULL_KEY -- 2
* OVFL_PAGENO - page number of the next overflow page
* OVFLPAGE -- 0
*
* Case 2:
* This page contains no key, but part of a large
* data field, which is continued on the next page.
*
* Page format it:
* DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE
*
* KEY_OFF -- offset of the beginning of the data on