[BACK]Return to btree.h CVS log [TXT][DIR] Up to [cvs.NetBSD.org] / src / lib / libc / db / btree

Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.

Diff for /src/lib/libc/db/btree/btree.h between version 1.16.6.1 and 1.16.6.2

version 1.16.6.1, 2008/08/26 21:18:38 version 1.16.6.2, 2008/08/26 21:18:39
Line 0 
Line 1 
   /*      $NetBSD$        */
   
   /*-
    * Copyright (c) 1991, 1993, 1994
    *      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. 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.
    *
    *      @(#)btree.h     8.11 (Berkeley) 8/17/94
    */
   
   #if HAVE_NBTOOL_CONFIG_H
   #include "nbtool_config.h"
   #endif
   
   /* 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 */
   #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 */
           uint32_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(uint32_t) + sizeof(indx_t) + sizeof(indx_t))
   
   #define _NEXTINDEX(p) (((p)->lower - BTDATAOFF) / sizeof(indx_t))
   #ifdef _DIAGNOSTIC
   static __inline indx_t
   NEXTINDEX(const PAGE *p) {
           size_t x = _NEXTINDEX(p);
           _DBFIT(x, indx_t);
           return (indx_t)x;
   }
   #else
   #define NEXTINDEX(p) (indx_t)_NEXTINDEX(p)
   #endif
   
   /*
    * 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 BTLALIGN(n)     (((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1))
   #define NOVFLSIZE       (sizeof(pgno_t) + sizeof(uint32_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 {
           uint32_t ksize;                 /* key size */
           pgno_t  pgno;                   /* page number stored on */
   #define P_BIGDATA       0x01            /* overflow data */
   #define P_BIGKEY        0x02            /* overflow key */
           uint8_t flags;
           char    bytes[1];               /* data */
   } BINTERNAL;
   
   /* Get the page's BINTERNAL structure at index indx. */
   #define GETBINTERNAL(pg, indx)                                          \
           ((BINTERNAL *)(void *)((char *)(void *)(pg) + (pg)->linp[indx]))
   
   /* Get the number of bytes in the entry. */
   #define _NBINTERNAL(len)                                                \
       BTLALIGN(sizeof(uint32_t) + sizeof(pgno_t) + sizeof(uint8_t) + (len))
   #ifdef _DIAGNOSTIC
   static __inline uint32_t
   NBINTERNAL(uint32_t len) {
           size_t x = _NBINTERNAL(len);
           _DBFIT(x, uint32_t);
           return (uint32_t)x;
   }
   #else
   #define NBINTERNAL(len) (uint32_t)_NBINTERNAL(len)
   #endif
   
   /* Copy a BINTERNAL entry to the page. */
   #define WR_BINTERNAL(p, size, pgno, flags) do {                         \
           _DBFIT(size, uint32_t);                                         \
           *(uint32_t *)(void *)p = (uint32_t)size;                        \
           p += sizeof(uint32_t);                                          \
           *(pgno_t *)(void *)p = pgno;                                    \
           p += sizeof(pgno_t);                                            \
           *(uint8_t *)(void *)p = flags;                                  \
           p += sizeof(uint8_t);                                           \
   } while (/*CONSTCOND*/0)
   
   /*
    * 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 *)(void *)((char *)(void *)(pg) + (pg)->linp[indx]))
   
   /* Get the number of bytes in the entry. */
   #define NRINTERNAL                                                      \
           BTLALIGN(sizeof(recno_t) + sizeof(pgno_t))
   
   /* Copy a RINTERAL entry to the page. */
   #define WR_RINTERNAL(p, nrecs, pgno) do {                               \
           *(recno_t *)(void *)p = nrecs;                                  \
           p += sizeof(recno_t);                                           \
           *(pgno_t *)(void *)p = pgno;                                    \
   } while (/*CONSTCOND*/0)
   
   /* For the btree leaf pages, the item is a key and data pair. */
   typedef struct _bleaf {
           uint32_t        ksize;          /* size of key */
           uint32_t        dsize;          /* size of data */
           uint8_t flags;                  /* P_BIGDATA, P_BIGKEY */
           char    bytes[1];               /* data */
   } BLEAF;
   
   /* Get the page's BLEAF structure at index indx. */
   #define GETBLEAF(pg, indx)                                              \
           ((BLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx]))
   
   
   /* Get the number of bytes in the user's key/data pair. */
   #define _NBLEAFDBT(ksize, dsize)                                        \
       BTLALIGN(sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uint8_t) +    \
               (ksize) + (dsize))
   #ifdef _DIAGNOSTIC
   static __inline uint32_t
   NBLEAFDBT(size_t k, size_t d) {
           size_t x = _NBLEAFDBT(k, d);
           _DBFIT(x, uint32_t);
           return (uint32_t)x;
   }
   #else
   #define NBLEAFDBT(p, q) (uint32_t)_NBLEAFDBT(p, q)
   #endif
   
   /* Get the number of bytes in the entry. */
   #define NBLEAF(p)       NBLEAFDBT((p)->ksize, (p)->dsize)
   
   /* Copy a BLEAF entry to the page. */
   #define WR_BLEAF(p, key, data, flags) do {                              \
           _DBFIT(key->size, uint32_t);                                    \
           *(uint32_t *)(void *)p = (uint32_t)key->size;                   \
           p += sizeof(uint32_t);                                          \
           _DBFIT(data->size, uint32_t);                                   \
           *(uint32_t *)(void *)p = (uint32_t)data->size;                  \
           p += sizeof(uint32_t);                                          \
           *(uint8_t *)(void *)p = flags;                                  \
           p += sizeof(uint8_t);                                           \
           (void)memmove(p, key->data, key->size);                         \
           p += key->size;                                                 \
           (void)memmove(p, data->data, data->size);                       \
   } while (/*CONSTCOND*/0)
   
   /* For the recno leaf pages, the item is a data entry. */
   typedef struct _rleaf {
           uint32_t        dsize;          /* size of data */
           uint8_t flags;                  /* P_BIGDATA */
           char    bytes[1];
   } RLEAF;
   
   /* Get the page's RLEAF structure at index indx. */
   #define GETRLEAF(pg, indx)                                              \
           ((RLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx]))
   
   #define _NRLEAFDBT(dsize)                                               \
           BTLALIGN(sizeof(uint32_t) + sizeof(uint8_t) + (dsize))
   
   #ifdef _DIAGNOSTIC
   static __inline uint32_t
   NRLEAFDBT(size_t d) {
           size_t x = _NRLEAFDBT(d);
           _DBFIT(x, uint32_t);
           return (uint32_t)x;
   }
   #else
   #define NRLEAFDBT(d)    (uint32_t)_NRLEAFDBT(d)
   #endif
   
   /* Get the number of bytes in the entry. */
   #define NRLEAF(p)       NRLEAFDBT((p)->dsize)
   
   /* Get the number of bytes from the user's data. */
   
   /* Copy a RLEAF entry to the page. */
   #define WR_RLEAF(p, data, flags) do {                                   \
           _DBFIT(data->size, uint32_t);                                   \
           *(uint32_t *)(void *)p = (uint32_t)data->size;                  \
           p += sizeof(uint32_t);                                          \
           *(uint8_t *)(void *)p = flags;                                  \
           p += sizeof(uint8_t);                                           \
           memmove(p, data->data, data->size);                             \
   } while (/*CONSTCOND*/0)
   
   /*
    * 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.
    */
   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;
   
   /*
    * 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. */
           uint8_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 {
           uint32_t        magic;          /* magic number */
           uint32_t        version;        /* version */
           uint32_t        psize;          /* page size */
           uint32_t        free;           /* page number of first free page */
           uint32_t        nrecs;          /* R: number of records */
   
   #define SAVEMETA        (B_NODUPS | R_RECNO)
           uint32_t        flags;          /* bt_flags & SAVEMETA */
   } 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 */
   
           CURSOR    bt_cursor;            /* cursor */
   
   #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 */
   
           DBT       bt_rkey;              /* returned key */
           DBT       bt_rdata;             /* returned data */
   
           int       bt_fd;                /* tree file descriptor */
   
           pgno_t    bt_free;              /* next free page */
           uint32_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)(const DBT *, const DBT *);
                                           /* B: prefix comparison function */
           size_t  (*bt_pfx)(const DBT *, const DBT *);
                                           /* R: recno input function */
           int     (*bt_irec)(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 */
           uint8_t   bt_bval;              /* R: delimiting byte/pad character */
   
   /*
    * NB:
    * B_NODUPS and R_RECNO are stored on disk, and may not be changed.
    */
   #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 R_RECNO         0x00080         /* record oriented tree */
   
   #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. */
           uint32_t flags;
   } BTREE;
   
   #include "extern.h"

Legend:
Removed from v.1.16.6.1  
changed lines
  Added in v.1.16.6.2

CVSweb <webmaster@jp.NetBSD.org>