usr/src/lib/krb5/plugins/kdb/db2/libdb2/btree/btree.h

   1 /*
   2  * Copyright (c) 1997-2000 by Sun Microsystems, Inc.
   3  * All rights reserved.
   4  */
   5
   6 #ifndef _KRB5_BTREE_H
   7 #define _KRB5_BTREE_H
   8
   9 #pragma ident   "%Z%%M% %I%     %E% SMI"
  10
  11 #ifdef  __cplusplus
  12 extern "C" {
  13 #endif
  14
  15
  16 /*-
  17  * Copyright (c) 1991, 1993, 1994
  18  *      The Regents of the University of California.  All rights reserved.
  19  *
  20  * This code is derived from software contributed to Berkeley by
  21  * Mike Olson.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the above copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *      This product includes software developed by the University of
  34  *      California, Berkeley and its contributors.
  35  * 4. Neither the name of the University nor the names of its contributors
  36  *    may be used to endorse or promote products derived from this software
  37  *    without specific prior written permission.
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  40  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  42  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  43  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  44  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  45  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  47  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  48  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  49  * SUCH DAMAGE.
  50  *
  51  *      @(#)btree.h     8.11 (Berkeley) 8/17/94
  52  */
  53
  54 /* Macros to set/clear/test flags. */
  55 #define F_SET(p, f)     (p)->flags |= (f)
  56 #define F_CLR(p, f)     (p)->flags &= ~(f)
  57 #define F_ISSET(p, f)   ((p)->flags & (f))
  58
  59 #include "mpool.h"
  60
  61 #define DEFMINKEYPAGE   (2)             /* Minimum keys per page */
  62 #define MINCACHE        (5)             /* Minimum cached pages */
  63 #define MINPSIZE        (512)           /* Minimum page size */
  64
  65 /*
  66  * Page 0 of a btree file contains a copy of the meta-data.  This page is also
  67  * used as an out-of-band page, i.e. page pointers that point to nowhere point
  68  * to page 0.  Page 1 is the root of the btree.
  69  */
  70 #define P_INVALID        0              /* Invalid tree page number. */
  71 #define P_META           0              /* Tree metadata page number. */
  72 #define P_ROOT           1              /* Tree root page number. */
  73
  74 /*
  75  * There are five page layouts in the btree: btree internal pages (BINTERNAL),
  76  * btree leaf pages (BLEAF), recno internal pages (RINTERNAL), recno leaf pages
  77  * (RLEAF) and overflow pages.  All five page types have a page header (PAGE).
  78  * This implementation requires that values within structures NOT be padded.
  79  * (ANSI C permits random padding.)  If your compiler pads randomly you'll have
  80  * to do some work to get this package to run.
  81  */
  82 typedef struct _page {
  83         db_pgno_t       pgno;                   /* this page's page number */
  84         db_pgno_t       prevpg;                 /* left sibling */
  85         db_pgno_t       nextpg;                 /* right sibling */
  86
  87 #define P_BINTERNAL     0x01            /* btree internal page */
  88 #define P_BLEAF         0x02            /* leaf page */
  89 #define P_OVERFLOW      0x04            /* overflow page */
  90 #define P_RINTERNAL     0x08            /* recno internal page */
  91 #define P_RLEAF         0x10            /* leaf page */
  92 #define P_TYPE          0x1f            /* type mask */
  93 #define P_PRESERVE      0x20            /* never delete this chain of pages */
  94         u_int32_t flags;
  95
  96         indx_t  lower;                  /* lower bound of free space on page */
  97         indx_t  upper;                  /* upper bound of free space on page */
  98         indx_t  linp[1];                /* indx_t-aligned VAR. LENGTH DATA */
  99 } PAGE;
 100
 101 /* First and next index. */
 102 #define BTDATAOFF                                                       \
 103         (sizeof(db_pgno_t) + sizeof(db_pgno_t) + sizeof(db_pgno_t) +            \
 104             sizeof(u_int32_t) + sizeof(indx_t) + sizeof(indx_t))
 105 #define NEXTINDEX(p)    (((p)->lower - BTDATAOFF) / sizeof(indx_t))
 106
 107 /*
 108  * For pages other than overflow pages, there is an array of offsets into the
 109  * rest of the page immediately following the page header.  Each offset is to
 110  * an item which is unique to the type of page.  The h_lower offset is just
 111  * past the last filled-in index.  The h_upper offset is the first item on the
 112  * page.  Offsets are from the beginning of the page.
 113  *
 114  * If an item is too big to store on a single page, a flag is set and the item
 115  * is a { page, size } pair such that the page is the first page of an overflow
 116  * chain with size bytes of item.  Overflow pages are simply bytes without any
 117  * external structure.
 118  *
 119  * The page number and size fields in the items are db_pgno_t-aligned so they can
 120  * be manipulated without copying.  (This presumes that 32 bit items can be
 121  * manipulated on this system.)
 122  */
 123 #define LALIGN(n)       (((n) + sizeof(db_pgno_t) - 1) & ~(sizeof(db_pgno_t) - 1))
 124 #define NOVFLSIZE       (sizeof(db_pgno_t) + sizeof(u_int32_t))
 125
 126 /*
 127  * For the btree internal pages, the item is a key.  BINTERNALs are {key, pgno}
 128  * pairs, such that the key compares less than or equal to all of the records
 129  * on that page.  For a tree without duplicate keys, an internal page with two
 130  * consecutive keys, a and b, will have all records greater than or equal to a
 131  * and less than b stored on the page associated with a.  Duplicate keys are
 132  * somewhat special and can cause duplicate internal and leaf page records and
 133  * some minor modifications of the above rule.
 134  */
 135 typedef struct _binternal {
 136         u_int32_t ksize;                /* key size */
 137         db_pgno_t       pgno;                   /* page number stored on */
 138 #define P_BIGDATA       0x01            /* overflow data */
 139 #define P_BIGKEY        0x02            /* overflow key */
 140         u_char  flags;
 141         char    bytes[1];               /* data */
 142 } BINTERNAL;
 143
 144 /* Get the page's BINTERNAL structure at index indx. */
 145 #define GETBINTERNAL(pg, indx)                                          \
 146         ((BINTERNAL *)((char *)(pg) + (pg)->linp[indx]))
 147
 148 /* Get the number of bytes in the entry. */
 149 #define NBINTERNAL(len)                                                 \
 150         LALIGN(sizeof(u_int32_t) + sizeof(db_pgno_t) + sizeof(u_char) + (len))
 151
 152 /* Copy a BINTERNAL entry to the page. */
 153 #define WR_BINTERNAL(p, size, pgno, flags) {                            \
 154         *(u_int32_t *)p = size;                                         \
 155         p += sizeof(u_int32_t);                                         \
 156         *(db_pgno_t *)p = pgno;                                         \
 157         p += sizeof(db_pgno_t);                                         \
 158         *(u_char *)p = flags;                                           \
 159         p += sizeof(u_char);                                            \
 160 }
 161
 162 /*
 163  * For the recno internal pages, the item is a page number with the number of
 164  * keys found on that page and below.
 165  */
 166 typedef struct _rinternal {
 167         recno_t nrecs;                  /* number of records */
 168         db_pgno_t       pgno;                   /* page number stored below */
 169 } RINTERNAL;
 170
 171 /* Get the page's RINTERNAL structure at index indx. */
 172 #define GETRINTERNAL(pg, indx)                                          \
 173         ((RINTERNAL *)((char *)(pg) + (pg)->linp[indx]))
 174
 175 /* Get the number of bytes in the entry. */
 176 #define NRINTERNAL                                                      \
 177         LALIGN(sizeof(recno_t) + sizeof(db_pgno_t))
 178
 179 /* Copy a RINTERAL entry to the page. */
 180 #define WR_RINTERNAL(p, nrecs, pgno) {                                  \
 181         *(recno_t *)p = nrecs;                                          \
 182         p += sizeof(recno_t);                                           \
 183         *(db_pgno_t *)p = pgno;                                         \
 184 }
 185
 186 /* For the btree leaf pages, the item is a key and data pair. */
 187 typedef struct _bleaf {
 188         u_int32_t       ksize;          /* size of key */
 189         u_int32_t       dsize;          /* size of data */
 190         u_char  flags;                  /* P_BIGDATA, P_BIGKEY */
 191         char    bytes[1];               /* data */
 192 } BLEAF;
 193
 194 /* Get the page's BLEAF structure at index indx. */
 195 #define GETBLEAF(pg, indx)                                              \
 196         ((BLEAF *)((char *)(pg) + (pg)->linp[indx]))
 197
 198 /* Get the number of bytes in the entry. */
 199 #define NBLEAF(p)       NBLEAFDBT((p)->ksize, (p)->dsize)
 200
 201 /* Get the number of bytes in the user's key/data pair. */
 202 #define NBLEAFDBT(ksize, dsize)                                         \
 203         LALIGN(sizeof(u_int32_t) + sizeof(u_int32_t) + sizeof(u_char) + \
 204             (ksize) + (dsize))
 205
 206 /* Copy a BLEAF entry to the page. */
 207 #define WR_BLEAF(p, key, data, flags) {                                 \
 208         *(u_int32_t *)p = key->size;                                    \
 209         p += sizeof(u_int32_t);                                         \
 210         *(u_int32_t *)p = data->size;                                   \
 211         p += sizeof(u_int32_t);                                         \
 212         *(u_char *)p = flags;                                           \
 213         p += sizeof(u_char);                                            \
 214         memmove(p, key->data, key->size);                               \
 215         p += key->size;                                                 \
 216         memmove(p, data->data, data->size);                             \
 217 }
 218
 219 /* For the recno leaf pages, the item is a data entry. */
 220 typedef struct _rleaf {
 221         u_int32_t       dsize;          /* size of data */
 222         u_char  flags;                  /* P_BIGDATA */
 223         char    bytes[1];
 224 } RLEAF;
 225
 226 /* Get the page's RLEAF structure at index indx. */
 227 #define GETRLEAF(pg, indx)                                              \
 228         ((RLEAF *)((char *)(pg) + (pg)->linp[indx]))
 229
 230 /* Get the number of bytes in the entry. */
 231 #define NRLEAF(p)       NRLEAFDBT((p)->dsize)
 232
 233 /* Get the number of bytes from the user's data. */
 234 #define NRLEAFDBT(dsize)                                                \
 235         LALIGN(sizeof(u_int32_t) + sizeof(u_char) + (dsize))
 236
 237 /* Copy a RLEAF entry to the page. */
 238 #define WR_RLEAF(p, data, flags) {                                      \
 239         *(u_int32_t *)p = data->size;                                   \
 240         p += sizeof(u_int32_t);                                         \
 241         *(u_char *)p = flags;                                           \
 242         p += sizeof(u_char);                                            \
 243         memmove(p, data->data, data->size);                             \
 244 }
 245
 246 /*
 247  * A record in the tree is either a pointer to a page and an index in the page
 248  * or a page number and an index.  These structures are used as a cursor, stack
 249  * entry and search returns as well as to pass records to other routines.
 250  *
 251  * One comment about searches.  Internal page searches must find the largest
 252  * record less than key in the tree so that descents work.  Leaf page searches
 253  * must find the smallest record greater than key so that the returned index
 254  * is the record's correct position for insertion.
 255  */
 256 typedef struct _epgno {
 257         db_pgno_t       pgno;                   /* the page number */
 258         indx_t  index;                  /* the index on the page */
 259 } EPGNO;
 260
 261 typedef struct _epg {
 262         PAGE    *page;                  /* the (pinned) page */
 263         indx_t   index;                 /* the index on the page */
 264 } EPG;
 265
 266 /*
 267  * About cursors.  The cursor (and the page that contained the key/data pair
 268  * that it referenced) can be deleted, which makes things a bit tricky.  If
 269  * there are no duplicates of the cursor key in the tree (i.e. B_NODUPS is set
 270  * or there simply aren't any duplicates of the key) we copy the key that it
 271  * referenced when it's deleted, and reacquire a new cursor key if the cursor
 272  * is used again.  If there are duplicates keys, we move to the next/previous
 273  * key, and set a flag so that we know what happened.  NOTE: if duplicate (to
 274  * the cursor) keys are added to the tree during this process, it is undefined
 275  * if they will be returned or not in a cursor scan.
 276  *
 277  * The flags determine the possible states of the cursor:
 278  *
 279  * CURS_INIT    The cursor references *something*.
 280  * CURS_ACQUIRE The cursor was deleted, and a key has been saved so that
 281  *              we can reacquire the right position in the tree.
 282  * CURS_AFTER, CURS_BEFORE
 283  *              The cursor was deleted, and now references a key/data pair
 284  *              that has not yet been returned, either before or after the
 285  *              deleted key/data pair.
 286  * XXX
 287  * This structure is broken out so that we can eventually offer multiple
 288  * cursors as part of the DB interface.
 289  */
 290 typedef struct _cursor {
 291         EPGNO    pg;                    /* B: Saved tree reference. */
 292         DBT      key;                   /* B: Saved key, or key.data == NULL. */
 293         recno_t  rcursor;               /* R: recno cursor (1-based) */
 294
 295 #define CURS_ACQUIRE    0x01            /*  B: Cursor needs to be reacquired. */
 296 #define CURS_AFTER      0x02            /*  B: Unreturned cursor after key. */
 297 #define CURS_BEFORE     0x04            /*  B: Unreturned cursor before key. */
 298 #define CURS_INIT       0x08            /* RB: Cursor initialized. */
 299         u_int8_t flags;
 300 } CURSOR;
 301
 302 /*
 303  * The metadata of the tree.  The nrecs field is used only by the RECNO code.
 304  * This is because the btree doesn't really need it and it requires that every
 305  * put or delete call modify the metadata.
 306  */
 307 typedef struct _btmeta {
 308         u_int32_t       magic;          /* magic number */
 309         u_int32_t       version;        /* version */
 310         u_int32_t       psize;          /* page size */
 311         u_int32_t       free;           /* page number of first free page */
 312         u_int32_t       nrecs;          /* R: number of records */
 313
 314 #define SAVEMETA        (B_NODUPS | R_RECNO)
 315         u_int32_t       flags;          /* bt_flags & SAVEMETA */
 316 } BTMETA;
 317
 318 /* The in-memory btree/recno data structure. */
 319 typedef struct _btree {
 320         MPOOL    *bt_mp;                /* memory pool cookie */
 321
 322         DB       *bt_dbp;               /* pointer to enclosing DB */
 323
 324         EPG       bt_cur;               /* current (pinned) page */
 325         PAGE     *bt_pinned;            /* page pinned across calls */
 326
 327         CURSOR    bt_cursor;            /* cursor */
 328
 329 #define BT_PUSH(t, p, i) {                                              \
 330         t->bt_sp->pgno = p;                                             \
 331         t->bt_sp->index = i;                                            \
 332         ++t->bt_sp;                                                     \
 333 }
 334 #define BT_POP(t)       (t->bt_sp == t->bt_stack ? NULL : --t->bt_sp)
 335 #define BT_CLR(t)       (t->bt_sp = t->bt_stack)
 336         EPGNO     bt_stack[50];         /* stack of parent pages */
 337         EPGNO    *bt_sp;                /* current stack pointer */
 338
 339         DBT       bt_rkey;              /* returned key */
 340         DBT       bt_rdata;             /* returned data */
 341
 342         int       bt_fd;                /* tree file descriptor */
 343
 344         db_pgno_t         bt_free;              /* next free page */
 345         u_int32_t bt_psize;             /* page size */
 346         indx_t    bt_ovflsize;          /* cut-off for key/data overflow */
 347         int       bt_lorder;            /* byte order */
 348                                         /* sorted order */
 349         enum { NOT, BACK, FORWARD } bt_order;
 350         EPGNO     bt_last;              /* last insert */
 351
 352                                         /* B: key comparison function */
 353         int     (*bt_cmp) __P((const DBT *, const DBT *));
 354                                         /* B: prefix comparison function */
 355         size_t  (*bt_pfx) __P((const DBT *, const DBT *));
 356                                         /* R: recno input function */
 357         int     (*bt_irec) __P((struct _btree *, recno_t));
 358
 359         FILE     *bt_rfp;               /* R: record FILE pointer */
 360         int       bt_rfd;               /* R: record file descriptor */
 361
 362         caddr_t   bt_cmap;              /* R: current point in mapped space */
 363         caddr_t   bt_smap;              /* R: start of mapped space */
 364         caddr_t   bt_emap;              /* R: end of mapped space */
 365         size_t    bt_msize;             /* R: size of mapped region. */
 366
 367         recno_t   bt_nrecs;             /* R: number of records */
 368         size_t    bt_reclen;            /* R: fixed record length */
 369         u_char    bt_bval;              /* R: delimiting byte/pad character */
 370
 371 /*
 372  * NB:
 373  * B_NODUPS and R_RECNO are stored on disk, and may not be changed.
 374  */
 375 #define B_INMEM         0x00001         /* in-memory tree */
 376 #define B_METADIRTY     0x00002         /* need to write metadata */
 377 #define B_MODIFIED      0x00004         /* tree modified */
 378 #define B_NEEDSWAP      0x00008         /* if byte order requires swapping */
 379 #define B_RDONLY        0x00010         /* read-only tree */
 380
 381 #define B_NODUPS        0x00020         /* no duplicate keys permitted */
 382 #define R_RECNO         0x00080         /* record oriented tree */
 383
 384 #define R_CLOSEFP       0x00040         /* opened a file pointer */
 385 #define R_EOF           0x00100         /* end of input file reached. */
 386 #define R_FIXLEN        0x00200         /* fixed length records */
 387 #define R_MEMMAPPED     0x00400         /* memory mapped file. */
 388 #define R_INMEM         0x00800         /* in-memory file */
 389 #define R_MODIFIED      0x01000         /* modified file */
 390 #define R_RDONLY        0x02000         /* read-only file */
 391
 392 #define B_DB_LOCK       0x04000         /* DB_LOCK specified. */
 393 #define B_DB_SHMEM      0x08000         /* DB_SHMEM specified. */
 394 #define B_DB_TXN        0x10000         /* DB_TXN specified. */
 395         u_int32_t flags;
 396 } BTREE;
 397
 398 #include "extern.h"
 399
 400 #ifdef  __cplusplus
 401 }
 402 #endif
 403
 404 #endif  /* !_KRB5_BTREE_H */