/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Mike Olson. * * 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. */ #include <mpool.h> #define DEFMINKEYPAGE (2) /* Minimum keys per page */ #define MINCACHE (5) /* Minimum cached pages */ #define MINPSIZE (512) /* Minimum page size */ /* * Page 0 of a btree file contains a copy of the meta-data. This page is also * used as an out-of-band page, i.e. page pointers that point to nowhere point * to page 0. Page 1 is the root of the btree. */ #define P_INVALID 0 /* Invalid tree page number. */ #define P_META 0 /* Tree metadata page number. */ #define P_ROOT 1 /* Tree root page number. */ /* * There are five page layouts in the btree: btree internal pages (BINTERNAL), * btree leaf pages (BLEAF), recno internal pages (RINTERNAL), recno leaf pages * (RLEAF) and overflow pages. All five page types have a page header (PAGE). * This implementation requires that values within structures NOT be padded. * (ANSI C permits random padding.) If your compiler pads randomly you'll have * to do some work to get this package to run. */ typedef struct _page { pgno_t pgno; /* this page's page number */ pgno_t prevpg; /* left sibling */ pgno_t nextpg; /* right sibling */ #define P_BINTERNAL 0x01 /* btree internal page */ #define P_BLEAF 0x02 /* leaf page */ #define P_OVERFLOW 0x04 /* overflow page */ #define P_RINTERNAL 0x08 /* recno internal page */ #define P_RLEAF 0x10 /* leaf page */ #define P_TYPE 0x1f /* type mask */ #define P_PRESERVE 0x20 /* never delete this chain of pages */ u_int32_t flags; indx_t lower; /* lower bound of free space on page */ indx_t upper; /* upper bound of free space on page */ indx_t linp[1]; /* indx_t-aligned VAR. LENGTH DATA */ } 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 NEXTINDEX(p) (((p)->lower - BTDATAOFF) / sizeof(indx_t)) /* * For pages other than overflow pages, there is an array of offsets into the * rest of the page immediately following the page header. Each offset is to * an item which is unique to the type of page. The h_lower offset is just * past the last filled-in index. The h_upper offset is the first item on the * page. Offsets are from the beginning of the page. * * If an item is too big to store on a single page, a flag is set and the item * is a { page, size } pair such that the page is the first page of an overflow * chain with size bytes of item. Overflow pages are simply bytes without any * external structure. * * The page number and size fields in the items are pgno_t-aligned so they can * 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 NOVFLSIZE (sizeof(pgno_t) + sizeof(size_t)) /* * For the btree internal pages, the item is a key. BINTERNALs are {key, pgno} * pairs, such that the key compares less than or equal to all of the records * on that page. For a tree without duplicate keys, an internal page with two * consecutive keys, a and b, will have all records greater than or equal to a * and less than b stored on the page associated with a. Duplicate keys are * somewhat special and can cause duplicate internal and leaf page records and * some minor modifications of the above rule. */ typedef struct _binternal { size_t ksize; /* key size */ pgno_t pgno; /* page number stored on */ #define P_BIGDATA 0x01 /* overflow data */ #define P_BIGKEY 0x02 /* overflow key */ u_char flags; char bytes[1]; /* data */ } BINTERNAL; /* Get the page's BINTERNAL structure at index indx. */ #define GETBINTERNAL(pg, indx) \ ((BINTERNAL *)((char *)(pg) + (pg)->linp[indx])) /* Get the number of bytes in the entry. */ #define NBINTERNAL(len) \ LALIGN(sizeof(size_t) + sizeof(pgno_t) + sizeof(u_char) + (len)) /* Copy a BINTERNAL entry to the page. */ #define WR_BINTERNAL(p, size, pgno, flags) { \ *(size_t *)p = size; \ p += sizeof(size_t); \ *(pgno_t *)p = pgno; \ p += sizeof(pgno_t); \ *(u_char *)p = flags; \ p += sizeof(u_char); \ } /* * For the recno internal pages, the item is a page number with the number of * keys found on that page and below. */ typedef struct _rinternal { recno_t nrecs; /* number of records */ pgno_t pgno; /* page number stored below */ } RINTERNAL; /* Get the page's RINTERNAL structure at index indx. */ #define GETRINTERNAL(pg, indx) \ ((RINTERNAL *)((char *)(pg) + (pg)->linp[indx])) /* Get the number of bytes in the entry. */ #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; \ } /* For the btree leaf pages, the item is a key and data pair. */ typedef struct _bleaf { size_t ksize; /* size of key */ size_t dsize; /* size of data */ u_char flags; /* P_BIGDATA, P_BIGKEY */ char bytes[1]; /* data */ } BLEAF; /* Get the page's BLEAF structure at index 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(size_t) + sizeof(size_t) + sizeof(u_char) + \ (ksize) + (dsize)) /* Copy a BLEAF entry to the page. */ #define WR_BLEAF(p, key, data, flags) { \ *(size_t *)p = key->size; \ p += sizeof(size_t); \ *(size_t *)p = data->size; \ p += sizeof(size_t); \ *(u_char *)p = flags; \ p += sizeof(u_char); \ memmove(p, key->data, key->size); \ p += key->size; \ memmove(p, data->data, data->size); \ } /* For the recno leaf pages, the item is a data entry. */ typedef struct _rleaf { size_t dsize; /* size of data */ u_char flags; /* P_BIGDATA */ char bytes[1]; } RLEAF; /* Get the page's RLEAF structure at index 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) \ LALIGN(sizeof(size_t) + sizeof(u_char) + (dsize)) /* Copy a RLEAF entry to the page. */ #define WR_RLEAF(p, data, flags) { \ *(size_t *)p = data->size; \ p += sizeof(size_t); \ *(u_char *)p = flags; \ p += sizeof(u_char); \ memmove(p, data->data, data->size); \ } /* * A record in the tree is either a pointer to a page and an index in the page * or a page number and an index. These structures are used as a cursor, stack * entry and search returns as well as to pass records to other routines. * * One comment about searches. Internal page searches must find the largest * 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 */ indx_t index; /* the index on the page */ } EPGNO; typedef struct _epg { PAGE *page; /* the (pinned) page */ indx_t index; /* the index on the page */ } EPG; /* * The metadata of the tree. The m_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 */ #define SAVEMETA (B_NODUPS | R_RECNO) u_int32_t m_flags; /* bt_flags & SAVEMETA */ u_int32_t m_unused; /* unused */ } BTMETA; /* The in-memory btree/recno data structure. */ typedef struct _btree { MPOOL *bt_mp; /* memory pool cookie */ DB *bt_dbp; /* pointer to enclosing DB */ 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) */ #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 */ char *bt_kbuf; /* key buffer */ size_t bt_kbufsz; /* key buffer size */ char *bt_dbuf; /* data buffer */ size_t bt_dbufsz; /* data buffer size */ int bt_fd; /* tree file descriptor */ 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 */ /* sorted order */ enum { NOT, BACK, FORWARD } bt_order; EPGNO bt_last; /* last insert */ /* B: key comparison function */ int (*bt_cmp) __P((const DBT *, const DBT *)); /* B: prefix comparison function */ size_t (*bt_pfx) __P((const DBT *, const DBT *)); /* 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 */ 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 */ /* * 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_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 */ } 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 "bt_extern.h"