version 1.16.6.1, 2008/08/26 21:18:38 |
version 1.16.6.2, 2008/08/26 21:18:39 |
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/* $NetBSD$ */ |
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/*- |
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* Copyright (c) 1991, 1993, 1994 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Mike Olson. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* @(#)btree.h 8.11 (Berkeley) 8/17/94 |
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*/ |
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#if HAVE_NBTOOL_CONFIG_H |
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#include "nbtool_config.h" |
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#endif |
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/* Macros to set/clear/test flags. */ |
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#define F_SET(p, f) (p)->flags |= (f) |
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#define F_CLR(p, f) (p)->flags &= ~(f) |
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#define F_ISSET(p, f) ((p)->flags & (f)) |
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#include <mpool.h> |
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#define DEFMINKEYPAGE (2) /* Minimum keys per page */ |
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#define MINCACHE (5) /* Minimum cached pages */ |
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#define MINPSIZE (512) /* Minimum page size */ |
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/* |
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* Page 0 of a btree file contains a copy of the meta-data. This page is also |
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* used as an out-of-band page, i.e. page pointers that point to nowhere point |
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* to page 0. Page 1 is the root of the btree. |
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*/ |
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#define P_INVALID 0 /* Invalid tree page number. */ |
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#define P_META 0 /* Tree metadata page number. */ |
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#define P_ROOT 1 /* Tree root page number. */ |
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/* |
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* There are five page layouts in the btree: btree internal pages (BINTERNAL), |
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* btree leaf pages (BLEAF), recno internal pages (RINTERNAL), recno leaf pages |
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* (RLEAF) and overflow pages. All five page types have a page header (PAGE). |
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* This implementation requires that values within structures NOT be padded. |
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* (ANSI C permits random padding.) If your compiler pads randomly you'll have |
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* to do some work to get this package to run. |
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*/ |
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typedef struct _page { |
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pgno_t pgno; /* this page's page number */ |
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pgno_t prevpg; /* left sibling */ |
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pgno_t nextpg; /* right sibling */ |
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#define P_BINTERNAL 0x01 /* btree internal page */ |
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#define P_BLEAF 0x02 /* leaf page */ |
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#define P_OVERFLOW 0x04 /* overflow page */ |
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#define P_RINTERNAL 0x08 /* recno internal page */ |
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#define P_RLEAF 0x10 /* leaf page */ |
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#define P_TYPE 0x1f /* type mask */ |
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#define P_PRESERVE 0x20 /* never delete this chain of pages */ |
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uint32_t flags; |
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indx_t lower; /* lower bound of free space on page */ |
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indx_t upper; /* upper bound of free space on page */ |
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indx_t linp[1]; /* indx_t-aligned VAR. LENGTH DATA */ |
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} PAGE; |
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/* First and next index. */ |
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#define BTDATAOFF \ |
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(sizeof(pgno_t) + sizeof(pgno_t) + sizeof(pgno_t) + \ |
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sizeof(uint32_t) + sizeof(indx_t) + sizeof(indx_t)) |
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#define _NEXTINDEX(p) (((p)->lower - BTDATAOFF) / sizeof(indx_t)) |
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#ifdef _DIAGNOSTIC |
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static __inline indx_t |
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NEXTINDEX(const PAGE *p) { |
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size_t x = _NEXTINDEX(p); |
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_DBFIT(x, indx_t); |
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return (indx_t)x; |
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} |
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#else |
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#define NEXTINDEX(p) (indx_t)_NEXTINDEX(p) |
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#endif |
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/* |
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* For pages other than overflow pages, there is an array of offsets into the |
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* rest of the page immediately following the page header. Each offset is to |
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* an item which is unique to the type of page. The h_lower offset is just |
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* past the last filled-in index. The h_upper offset is the first item on the |
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* page. Offsets are from the beginning of the page. |
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* |
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* If an item is too big to store on a single page, a flag is set and the item |
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* is a { page, size } pair such that the page is the first page of an overflow |
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* chain with size bytes of item. Overflow pages are simply bytes without any |
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* external structure. |
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* |
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* The page number and size fields in the items are pgno_t-aligned so they can |
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* be manipulated without copying. (This presumes that 32 bit items can be |
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* manipulated on this system.) |
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*/ |
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#define BTLALIGN(n) (((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1)) |
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#define NOVFLSIZE (sizeof(pgno_t) + sizeof(uint32_t)) |
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/* |
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* For the btree internal pages, the item is a key. BINTERNALs are {key, pgno} |
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* pairs, such that the key compares less than or equal to all of the records |
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* on that page. For a tree without duplicate keys, an internal page with two |
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* consecutive keys, a and b, will have all records greater than or equal to a |
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* and less than b stored on the page associated with a. Duplicate keys are |
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* somewhat special and can cause duplicate internal and leaf page records and |
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* some minor modifications of the above rule. |
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*/ |
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typedef struct _binternal { |
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uint32_t ksize; /* key size */ |
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pgno_t pgno; /* page number stored on */ |
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#define P_BIGDATA 0x01 /* overflow data */ |
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#define P_BIGKEY 0x02 /* overflow key */ |
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uint8_t flags; |
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char bytes[1]; /* data */ |
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} BINTERNAL; |
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/* Get the page's BINTERNAL structure at index indx. */ |
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#define GETBINTERNAL(pg, indx) \ |
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((BINTERNAL *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) |
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/* Get the number of bytes in the entry. */ |
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#define _NBINTERNAL(len) \ |
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BTLALIGN(sizeof(uint32_t) + sizeof(pgno_t) + sizeof(uint8_t) + (len)) |
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#ifdef _DIAGNOSTIC |
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static __inline uint32_t |
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NBINTERNAL(uint32_t len) { |
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size_t x = _NBINTERNAL(len); |
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_DBFIT(x, uint32_t); |
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return (uint32_t)x; |
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} |
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#else |
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#define NBINTERNAL(len) (uint32_t)_NBINTERNAL(len) |
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#endif |
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/* Copy a BINTERNAL entry to the page. */ |
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#define WR_BINTERNAL(p, size, pgno, flags) do { \ |
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_DBFIT(size, uint32_t); \ |
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*(uint32_t *)(void *)p = (uint32_t)size; \ |
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p += sizeof(uint32_t); \ |
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*(pgno_t *)(void *)p = pgno; \ |
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p += sizeof(pgno_t); \ |
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*(uint8_t *)(void *)p = flags; \ |
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p += sizeof(uint8_t); \ |
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} while (/*CONSTCOND*/0) |
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/* |
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* For the recno internal pages, the item is a page number with the number of |
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* keys found on that page and below. |
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*/ |
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typedef struct _rinternal { |
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recno_t nrecs; /* number of records */ |
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pgno_t pgno; /* page number stored below */ |
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} RINTERNAL; |
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/* Get the page's RINTERNAL structure at index indx. */ |
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#define GETRINTERNAL(pg, indx) \ |
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((RINTERNAL *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) |
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/* Get the number of bytes in the entry. */ |
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#define NRINTERNAL \ |
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BTLALIGN(sizeof(recno_t) + sizeof(pgno_t)) |
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/* Copy a RINTERAL entry to the page. */ |
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#define WR_RINTERNAL(p, nrecs, pgno) do { \ |
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*(recno_t *)(void *)p = nrecs; \ |
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p += sizeof(recno_t); \ |
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*(pgno_t *)(void *)p = pgno; \ |
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} while (/*CONSTCOND*/0) |
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/* For the btree leaf pages, the item is a key and data pair. */ |
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typedef struct _bleaf { |
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uint32_t ksize; /* size of key */ |
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uint32_t dsize; /* size of data */ |
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uint8_t flags; /* P_BIGDATA, P_BIGKEY */ |
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char bytes[1]; /* data */ |
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} BLEAF; |
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/* Get the page's BLEAF structure at index indx. */ |
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#define GETBLEAF(pg, indx) \ |
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((BLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) |
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/* Get the number of bytes in the user's key/data pair. */ |
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#define _NBLEAFDBT(ksize, dsize) \ |
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BTLALIGN(sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uint8_t) + \ |
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(ksize) + (dsize)) |
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#ifdef _DIAGNOSTIC |
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static __inline uint32_t |
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NBLEAFDBT(size_t k, size_t d) { |
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size_t x = _NBLEAFDBT(k, d); |
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_DBFIT(x, uint32_t); |
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return (uint32_t)x; |
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} |
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#else |
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#define NBLEAFDBT(p, q) (uint32_t)_NBLEAFDBT(p, q) |
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#endif |
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/* Get the number of bytes in the entry. */ |
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#define NBLEAF(p) NBLEAFDBT((p)->ksize, (p)->dsize) |
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/* Copy a BLEAF entry to the page. */ |
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#define WR_BLEAF(p, key, data, flags) do { \ |
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_DBFIT(key->size, uint32_t); \ |
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*(uint32_t *)(void *)p = (uint32_t)key->size; \ |
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p += sizeof(uint32_t); \ |
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_DBFIT(data->size, uint32_t); \ |
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*(uint32_t *)(void *)p = (uint32_t)data->size; \ |
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p += sizeof(uint32_t); \ |
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*(uint8_t *)(void *)p = flags; \ |
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p += sizeof(uint8_t); \ |
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(void)memmove(p, key->data, key->size); \ |
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p += key->size; \ |
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(void)memmove(p, data->data, data->size); \ |
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} while (/*CONSTCOND*/0) |
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/* For the recno leaf pages, the item is a data entry. */ |
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typedef struct _rleaf { |
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uint32_t dsize; /* size of data */ |
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uint8_t flags; /* P_BIGDATA */ |
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char bytes[1]; |
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} RLEAF; |
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/* Get the page's RLEAF structure at index indx. */ |
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#define GETRLEAF(pg, indx) \ |
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((RLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) |
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#define _NRLEAFDBT(dsize) \ |
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BTLALIGN(sizeof(uint32_t) + sizeof(uint8_t) + (dsize)) |
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#ifdef _DIAGNOSTIC |
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static __inline uint32_t |
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NRLEAFDBT(size_t d) { |
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size_t x = _NRLEAFDBT(d); |
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_DBFIT(x, uint32_t); |
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return (uint32_t)x; |
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} |
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#else |
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#define NRLEAFDBT(d) (uint32_t)_NRLEAFDBT(d) |
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#endif |
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/* Get the number of bytes in the entry. */ |
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#define NRLEAF(p) NRLEAFDBT((p)->dsize) |
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/* Get the number of bytes from the user's data. */ |
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/* Copy a RLEAF entry to the page. */ |
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#define WR_RLEAF(p, data, flags) do { \ |
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_DBFIT(data->size, uint32_t); \ |
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*(uint32_t *)(void *)p = (uint32_t)data->size; \ |
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p += sizeof(uint32_t); \ |
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*(uint8_t *)(void *)p = flags; \ |
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p += sizeof(uint8_t); \ |
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memmove(p, data->data, data->size); \ |
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} while (/*CONSTCOND*/0) |
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/* |
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* A record in the tree is either a pointer to a page and an index in the page |
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* or a page number and an index. These structures are used as a cursor, stack |
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* entry and search returns as well as to pass records to other routines. |
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* |
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* One comment about searches. Internal page searches must find the largest |
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* record less than key in the tree so that descents work. Leaf page searches |
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* must find the smallest record greater than key so that the returned index |
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* is the record's correct position for insertion. |
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*/ |
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typedef struct _epgno { |
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pgno_t pgno; /* the page number */ |
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indx_t index; /* the index on the page */ |
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} EPGNO; |
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typedef struct _epg { |
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PAGE *page; /* the (pinned) page */ |
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indx_t index; /* the index on the page */ |
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} EPG; |
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/* |
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* About cursors. The cursor (and the page that contained the key/data pair |
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* that it referenced) can be deleted, which makes things a bit tricky. If |
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* there are no duplicates of the cursor key in the tree (i.e. B_NODUPS is set |
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* or there simply aren't any duplicates of the key) we copy the key that it |
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* referenced when it's deleted, and reacquire a new cursor key if the cursor |
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* is used again. If there are duplicates keys, we move to the next/previous |
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* key, and set a flag so that we know what happened. NOTE: if duplicate (to |
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* the cursor) keys are added to the tree during this process, it is undefined |
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* if they will be returned or not in a cursor scan. |
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* |
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* The flags determine the possible states of the cursor: |
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* |
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* CURS_INIT The cursor references *something*. |
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* CURS_ACQUIRE The cursor was deleted, and a key has been saved so that |
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* we can reacquire the right position in the tree. |
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* CURS_AFTER, CURS_BEFORE |
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* The cursor was deleted, and now references a key/data pair |
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* that has not yet been returned, either before or after the |
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* deleted key/data pair. |
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* XXX |
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* This structure is broken out so that we can eventually offer multiple |
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* cursors as part of the DB interface. |
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*/ |
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typedef struct _cursor { |
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EPGNO pg; /* B: Saved tree reference. */ |
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DBT key; /* B: Saved key, or key.data == NULL. */ |
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recno_t rcursor; /* R: recno cursor (1-based) */ |
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#define CURS_ACQUIRE 0x01 /* B: Cursor needs to be reacquired. */ |
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#define CURS_AFTER 0x02 /* B: Unreturned cursor after key. */ |
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#define CURS_BEFORE 0x04 /* B: Unreturned cursor before key. */ |
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#define CURS_INIT 0x08 /* RB: Cursor initialized. */ |
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uint8_t flags; |
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} CURSOR; |
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/* |
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* The metadata of the tree. The nrecs field is used only by the RECNO code. |
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* This is because the btree doesn't really need it and it requires that every |
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* put or delete call modify the metadata. |
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*/ |
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typedef struct _btmeta { |
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uint32_t magic; /* magic number */ |
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uint32_t version; /* version */ |
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uint32_t psize; /* page size */ |
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uint32_t free; /* page number of first free page */ |
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uint32_t nrecs; /* R: number of records */ |
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#define SAVEMETA (B_NODUPS | R_RECNO) |
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uint32_t flags; /* bt_flags & SAVEMETA */ |
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} BTMETA; |
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/* The in-memory btree/recno data structure. */ |
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typedef struct _btree { |
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MPOOL *bt_mp; /* memory pool cookie */ |
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DB *bt_dbp; /* pointer to enclosing DB */ |
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EPG bt_cur; /* current (pinned) page */ |
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PAGE *bt_pinned; /* page pinned across calls */ |
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CURSOR bt_cursor; /* cursor */ |
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#define BT_PUSH(t, p, i) { \ |
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t->bt_sp->pgno = p; \ |
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t->bt_sp->index = i; \ |
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++t->bt_sp; \ |
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} |
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#define BT_POP(t) (t->bt_sp == t->bt_stack ? NULL : --t->bt_sp) |
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#define BT_CLR(t) (t->bt_sp = t->bt_stack) |
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EPGNO bt_stack[50]; /* stack of parent pages */ |
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EPGNO *bt_sp; /* current stack pointer */ |
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DBT bt_rkey; /* returned key */ |
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DBT bt_rdata; /* returned data */ |
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int bt_fd; /* tree file descriptor */ |
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pgno_t bt_free; /* next free page */ |
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uint32_t bt_psize; /* page size */ |
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indx_t bt_ovflsize; /* cut-off for key/data overflow */ |
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int bt_lorder; /* byte order */ |
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/* sorted order */ |
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enum { NOT, BACK, FORWARD } bt_order; |
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EPGNO bt_last; /* last insert */ |
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/* B: key comparison function */ |
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int (*bt_cmp)(const DBT *, const DBT *); |
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/* B: prefix comparison function */ |
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size_t (*bt_pfx)(const DBT *, const DBT *); |
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/* R: recno input function */ |
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int (*bt_irec)(struct _btree *, recno_t); |
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FILE *bt_rfp; /* R: record FILE pointer */ |
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int bt_rfd; /* R: record file descriptor */ |
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caddr_t bt_cmap; /* R: current point in mapped space */ |
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caddr_t bt_smap; /* R: start of mapped space */ |
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caddr_t bt_emap; /* R: end of mapped space */ |
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size_t bt_msize; /* R: size of mapped region. */ |
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recno_t bt_nrecs; /* R: number of records */ |
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size_t bt_reclen; /* R: fixed record length */ |
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uint8_t bt_bval; /* R: delimiting byte/pad character */ |
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/* |
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* NB: |
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* B_NODUPS and R_RECNO are stored on disk, and may not be changed. |
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*/ |
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#define B_INMEM 0x00001 /* in-memory tree */ |
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#define B_METADIRTY 0x00002 /* need to write metadata */ |
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#define B_MODIFIED 0x00004 /* tree modified */ |
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#define B_NEEDSWAP 0x00008 /* if byte order requires swapping */ |
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#define B_RDONLY 0x00010 /* read-only tree */ |
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#define B_NODUPS 0x00020 /* no duplicate keys permitted */ |
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#define R_RECNO 0x00080 /* record oriented tree */ |
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#define R_CLOSEFP 0x00040 /* opened a file pointer */ |
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#define R_EOF 0x00100 /* end of input file reached. */ |
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#define R_FIXLEN 0x00200 /* fixed length records */ |
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#define R_MEMMAPPED 0x00400 /* memory mapped file. */ |
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#define R_INMEM 0x00800 /* in-memory file */ |
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#define R_MODIFIED 0x01000 /* modified file */ |
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#define R_RDONLY 0x02000 /* read-only file */ |
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#define B_DB_LOCK 0x04000 /* DB_LOCK specified. */ |
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#define B_DB_SHMEM 0x08000 /* DB_SHMEM specified. */ |
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#define B_DB_TXN 0x10000 /* DB_TXN specified. */ |
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uint32_t flags; |
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} BTREE; |
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#include "extern.h" |