1 /* $NetBSD: btree.h,v 1.18 2022/04/19 20:32:15 rillig Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Mike Olson. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)btree.h 8.11 (Berkeley) 8/17/94 35 */ 36 37 #if HAVE_NBTOOL_CONFIG_H 38 #include "nbtool_config.h" 39 #endif 40 41 /* Macros to set/clear/test flags. */ 42 #define F_SET(p, f) (p)->flags |= (f) 43 #define F_CLR(p, f) (p)->flags &= ~(f) 44 #define F_ISSET(p, f) ((p)->flags & (f)) 45 46 #include <mpool.h> 47 48 #define DEFMINKEYPAGE (2) /* Minimum keys per page */ 49 #define MINCACHE (5) /* Minimum cached pages */ 50 #define MINPSIZE (512) /* Minimum page size */ 51 52 /* 53 * Page 0 of a btree file contains a copy of the meta-data. This page is also 54 * used as an out-of-band page, i.e. page pointers that point to nowhere point 55 * to page 0. Page 1 is the root of the btree. 56 */ 57 #define P_INVALID 0 /* Invalid tree page number. */ 58 #define P_META 0 /* Tree metadata page number. */ 59 #define P_ROOT 1 /* Tree root page number. */ 60 61 /* 62 * There are five page layouts in the btree: btree internal pages (BINTERNAL), 63 * btree leaf pages (BLEAF), recno internal pages (RINTERNAL), recno leaf pages 64 * (RLEAF) and overflow pages. All five page types have a page header (PAGE). 65 * This implementation requires that values within structures NOT be padded. 66 * (ANSI C permits random padding.) If your compiler pads randomly you'll have 67 * to do some work to get this package to run. 68 */ 69 typedef struct _page { 70 pgno_t pgno; /* this page's page number */ 71 pgno_t prevpg; /* left sibling */ 72 pgno_t nextpg; /* right sibling */ 73 74 #define P_BINTERNAL 0x01 /* btree internal page */ 75 #define P_BLEAF 0x02 /* leaf page */ 76 #define P_OVERFLOW 0x04 /* overflow page */ 77 #define P_RINTERNAL 0x08 /* recno internal page */ 78 #define P_RLEAF 0x10 /* leaf page */ 79 #define P_TYPE 0x1f /* type mask */ 80 #define P_PRESERVE 0x20 /* never delete this chain of pages */ 81 uint32_t flags; 82 83 indx_t lower; /* lower bound of free space on page */ 84 indx_t upper; /* upper bound of free space on page */ 85 indx_t linp[1]; /* indx_t-aligned VAR. LENGTH DATA */ 86 } PAGE; 87 88 /* First and next index. */ 89 #define BTDATAOFF \ 90 (sizeof(pgno_t) + sizeof(pgno_t) + sizeof(pgno_t) + \ 91 sizeof(uint32_t) + sizeof(indx_t) + sizeof(indx_t)) 92 93 #define _NEXTINDEX(p) (((p)->lower - BTDATAOFF) / sizeof(indx_t)) 94 #ifdef _DIAGNOSTIC 95 static __inline indx_t 96 NEXTINDEX(const PAGE *p) { 97 size_t x = _NEXTINDEX(p); 98 _DBFIT(x, indx_t); 99 return (indx_t)x; 100 } 101 #else 102 #define NEXTINDEX(p) (indx_t)_NEXTINDEX(p) 103 #endif 104 105 /* 106 * For pages other than overflow pages, there is an array of offsets into the 107 * rest of the page immediately following the page header. Each offset is to 108 * an item which is unique to the type of page. The h_lower offset is just 109 * past the last filled-in index. The h_upper offset is the first item on the 110 * page. Offsets are from the beginning of the page. 111 * 112 * If an item is too big to store on a single page, a flag is set and the item 113 * is a { page, size } pair such that the page is the first page of an overflow 114 * chain with size bytes of item. Overflow pages are simply bytes without any 115 * external structure. 116 * 117 * The page number and size fields in the items are pgno_t-aligned so they can 118 * be manipulated without copying. (This presumes that 32 bit items can be 119 * manipulated on this system.) 120 */ 121 #define BTLALIGN(n) (((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1)) 122 #define NOVFLSIZE (sizeof(pgno_t) + sizeof(uint32_t)) 123 124 /* 125 * For the btree internal pages, the item is a key. BINTERNALs are {key, pgno} 126 * pairs, such that the key compares less than or equal to all of the records 127 * on that page. For a tree without duplicate keys, an internal page with two 128 * consecutive keys, a and b, will have all records greater than or equal to a 129 * and less than b stored on the page associated with a. Duplicate keys are 130 * somewhat special and can cause duplicate internal and leaf page records and 131 * some minor modifications of the above rule. 132 */ 133 typedef struct _binternal { 134 uint32_t ksize; /* key size */ 135 pgno_t pgno; /* page number stored on */ 136 #define P_BIGDATA 0x01 /* overflow data */ 137 #define P_BIGKEY 0x02 /* overflow key */ 138 uint8_t flags; 139 char bytes[1]; /* data */ 140 } BINTERNAL; 141 142 /* Get the page's BINTERNAL structure at index indx. */ 143 #define GETBINTERNAL(pg, indx) \ 144 ((BINTERNAL *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) 145 146 /* Get the number of bytes in the entry. */ 147 #define _NBINTERNAL(len) \ 148 BTLALIGN(sizeof(uint32_t) + sizeof(pgno_t) + sizeof(uint8_t) + (len)) 149 #ifdef _DIAGNOSTIC 150 static __inline uint32_t 151 NBINTERNAL(uint32_t len) { 152 size_t x = _NBINTERNAL(len); 153 _DBFIT(x, uint32_t); 154 return (uint32_t)x; 155 } 156 #else 157 #define NBINTERNAL(len) (uint32_t)_NBINTERNAL(len) 158 #endif 159 160 /* Copy a BINTERNAL entry to the page. */ 161 #define WR_BINTERNAL(p, size, pgno, flags) do { \ 162 _DBFIT(size, uint32_t); \ 163 *(uint32_t *)(void *)p = (uint32_t)size; \ 164 p += sizeof(uint32_t); \ 165 *(pgno_t *)(void *)p = pgno; \ 166 p += sizeof(pgno_t); \ 167 *(uint8_t *)(void *)p = flags; \ 168 p += sizeof(uint8_t); \ 169 } while (0) 170 171 /* 172 * For the recno internal pages, the item is a page number with the number of 173 * keys found on that page and below. 174 */ 175 typedef struct _rinternal { 176 recno_t nrecs; /* number of records */ 177 pgno_t pgno; /* page number stored below */ 178 } RINTERNAL; 179 180 /* Get the page's RINTERNAL structure at index indx. */ 181 #define GETRINTERNAL(pg, indx) \ 182 ((RINTERNAL *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) 183 184 /* Get the number of bytes in the entry. */ 185 #define NRINTERNAL \ 186 BTLALIGN(sizeof(recno_t) + sizeof(pgno_t)) 187 188 /* Copy a RINTERNAL entry to the page. */ 189 #define WR_RINTERNAL(p, nrecs, pgno) do { \ 190 *(recno_t *)(void *)p = nrecs; \ 191 p += sizeof(recno_t); \ 192 *(pgno_t *)(void *)p = pgno; \ 193 } while (0) 194 195 /* For the btree leaf pages, the item is a key and data pair. */ 196 typedef struct _bleaf { 197 uint32_t ksize; /* size of key */ 198 uint32_t dsize; /* size of data */ 199 uint8_t flags; /* P_BIGDATA, P_BIGKEY */ 200 char bytes[1]; /* data */ 201 } BLEAF; 202 203 /* Get the page's BLEAF structure at index indx. */ 204 #define GETBLEAF(pg, indx) \ 205 ((BLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) 206 207 208 /* Get the number of bytes in the user's key/data pair. */ 209 #define _NBLEAFDBT(ksize, dsize) \ 210 BTLALIGN(sizeof(uint32_t) + sizeof(uint32_t) + sizeof(uint8_t) + \ 211 (ksize) + (dsize)) 212 #ifdef _DIAGNOSTIC 213 static __inline uint32_t 214 NBLEAFDBT(size_t k, size_t d) { 215 size_t x = _NBLEAFDBT(k, d); 216 _DBFIT(x, uint32_t); 217 return (uint32_t)x; 218 } 219 #else 220 #define NBLEAFDBT(p, q) (uint32_t)_NBLEAFDBT(p, q) 221 #endif 222 223 /* Get the number of bytes in the entry. */ 224 #define NBLEAF(p) NBLEAFDBT((p)->ksize, (p)->dsize) 225 226 /* Copy a BLEAF entry to the page. */ 227 #define WR_BLEAF(p, key, data, flags) do { \ 228 _DBFIT(key->size, uint32_t); \ 229 *(uint32_t *)(void *)p = (uint32_t)key->size; \ 230 p += sizeof(uint32_t); \ 231 _DBFIT(data->size, uint32_t); \ 232 *(uint32_t *)(void *)p = (uint32_t)data->size; \ 233 p += sizeof(uint32_t); \ 234 *(uint8_t *)(void *)p = flags; \ 235 p += sizeof(uint8_t); \ 236 (void)memmove(p, key->data, key->size); \ 237 p += key->size; \ 238 (void)memmove(p, data->data, data->size); \ 239 } while (0) 240 241 /* For the recno leaf pages, the item is a data entry. */ 242 typedef struct _rleaf { 243 uint32_t dsize; /* size of data */ 244 uint8_t flags; /* P_BIGDATA */ 245 char bytes[1]; 246 } RLEAF; 247 248 /* Get the page's RLEAF structure at index indx. */ 249 #define GETRLEAF(pg, indx) \ 250 ((RLEAF *)(void *)((char *)(void *)(pg) + (pg)->linp[indx])) 251 252 #define _NRLEAFDBT(dsize) \ 253 BTLALIGN(sizeof(uint32_t) + sizeof(uint8_t) + (dsize)) 254 255 #ifdef _DIAGNOSTIC 256 static __inline uint32_t 257 NRLEAFDBT(size_t d) { 258 size_t x = _NRLEAFDBT(d); 259 _DBFIT(x, uint32_t); 260 return (uint32_t)x; 261 } 262 #else 263 #define NRLEAFDBT(d) (uint32_t)_NRLEAFDBT(d) 264 #endif 265 266 /* Get the number of bytes in the entry. */ 267 #define NRLEAF(p) NRLEAFDBT((p)->dsize) 268 269 /* Get the number of bytes from the user's data. */ 270 271 /* Copy a RLEAF entry to the page. */ 272 #define WR_RLEAF(p, data, flags) do { \ 273 _DBFIT(data->size, uint32_t); \ 274 *(uint32_t *)(void *)p = (uint32_t)data->size; \ 275 p += sizeof(uint32_t); \ 276 *(uint8_t *)(void *)p = flags; \ 277 p += sizeof(uint8_t); \ 278 memmove(p, data->data, data->size); \ 279 } while (0) 280 281 /* 282 * A record in the tree is either a pointer to a page and an index in the page 283 * or a page number and an index. These structures are used as a cursor, stack 284 * entry and search returns as well as to pass records to other routines. 285 * 286 * One comment about searches. Internal page searches must find the largest 287 * record less than key in the tree so that descents work. Leaf page searches 288 * must find the smallest record greater than key so that the returned index 289 * is the record's correct position for insertion. 290 */ 291 typedef struct _epgno { 292 pgno_t pgno; /* the page number */ 293 indx_t index; /* the index on the page */ 294 } EPGNO; 295 296 typedef struct _epg { 297 PAGE *page; /* the (pinned) page */ 298 indx_t index; /* the index on the page */ 299 } EPG; 300 301 /* 302 * About cursors. The cursor (and the page that contained the key/data pair 303 * that it referenced) can be deleted, which makes things a bit tricky. If 304 * there are no duplicates of the cursor key in the tree (i.e. B_NODUPS is set 305 * or there simply aren't any duplicates of the key) we copy the key that it 306 * referenced when it's deleted, and reacquire a new cursor key if the cursor 307 * is used again. If there are duplicates keys, we move to the next/previous 308 * key, and set a flag so that we know what happened. NOTE: if duplicate (to 309 * the cursor) keys are added to the tree during this process, it is undefined 310 * if they will be returned or not in a cursor scan. 311 * 312 * The flags determine the possible states of the cursor: 313 * 314 * CURS_INIT The cursor references *something*. 315 * CURS_ACQUIRE The cursor was deleted, and a key has been saved so that 316 * we can reacquire the right position in the tree. 317 * CURS_AFTER, CURS_BEFORE 318 * The cursor was deleted, and now references a key/data pair 319 * that has not yet been returned, either before or after the 320 * deleted key/data pair. 321 * XXX 322 * This structure is broken out so that we can eventually offer multiple 323 * cursors as part of the DB interface. 324 */ 325 typedef struct _cursor { 326 EPGNO pg; /* B: Saved tree reference. */ 327 DBT key; /* B: Saved key, or key.data == NULL. */ 328 recno_t rcursor; /* R: recno cursor (1-based) */ 329 330 #define CURS_ACQUIRE 0x01 /* B: Cursor needs to be reacquired. */ 331 #define CURS_AFTER 0x02 /* B: Unreturned cursor after key. */ 332 #define CURS_BEFORE 0x04 /* B: Unreturned cursor before key. */ 333 #define CURS_INIT 0x08 /* RB: Cursor initialized. */ 334 uint8_t flags; 335 } CURSOR; 336 337 /* 338 * The metadata of the tree. The nrecs field is used only by the RECNO code. 339 * This is because the btree doesn't really need it and it requires that every 340 * put or delete call modify the metadata. 341 */ 342 typedef struct _btmeta { 343 uint32_t magic; /* magic number */ 344 uint32_t version; /* version */ 345 uint32_t psize; /* page size */ 346 uint32_t free; /* page number of first free page */ 347 uint32_t nrecs; /* R: number of records */ 348 349 #define SAVEMETA (B_NODUPS | R_RECNO) 350 uint32_t flags; /* bt_flags & SAVEMETA */ 351 } BTMETA; 352 353 /* The in-memory btree/recno data structure. */ 354 typedef struct _btree { 355 MPOOL *bt_mp; /* memory pool cookie */ 356 357 DB *bt_dbp; /* pointer to enclosing DB */ 358 359 EPG bt_cur; /* current (pinned) page */ 360 PAGE *bt_pinned; /* page pinned across calls */ 361 362 CURSOR bt_cursor; /* cursor */ 363 364 #define BT_PUSH(t, p, i) { \ 365 t->bt_sp->pgno = p; \ 366 t->bt_sp->index = i; \ 367 ++t->bt_sp; \ 368 } 369 #define BT_POP(t) (t->bt_sp == t->bt_stack ? NULL : --t->bt_sp) 370 #define BT_CLR(t) (t->bt_sp = t->bt_stack) 371 EPGNO bt_stack[50]; /* stack of parent pages */ 372 EPGNO *bt_sp; /* current stack pointer */ 373 374 DBT bt_rkey; /* returned key */ 375 DBT bt_rdata; /* returned data */ 376 377 int bt_fd; /* tree file descriptor */ 378 379 pgno_t bt_free; /* next free page */ 380 uint32_t bt_psize; /* page size */ 381 indx_t bt_ovflsize; /* cut-off for key/data overflow */ 382 int bt_lorder; /* byte order */ 383 /* sorted order */ 384 enum { NOT, BACK, FORWARD } bt_order; 385 EPGNO bt_last; /* last insert */ 386 387 /* B: key comparison function */ 388 int (*bt_cmp)(const DBT *, const DBT *); 389 /* B: prefix comparison function */ 390 size_t (*bt_pfx)(const DBT *, const DBT *); 391 /* R: recno input function */ 392 int (*bt_irec)(struct _btree *, recno_t); 393 394 FILE *bt_rfp; /* R: record FILE pointer */ 395 int bt_rfd; /* R: record file descriptor */ 396 397 caddr_t bt_cmap; /* R: current point in mapped space */ 398 caddr_t bt_smap; /* R: start of mapped space */ 399 caddr_t bt_emap; /* R: end of mapped space */ 400 size_t bt_msize; /* R: size of mapped region. */ 401 402 recno_t bt_nrecs; /* R: number of records */ 403 size_t bt_reclen; /* R: fixed record length */ 404 uint8_t bt_bval; /* R: delimiting byte/pad character */ 405 406 /* 407 * NB: 408 * B_NODUPS and R_RECNO are stored on disk, and may not be changed. 409 */ 410 #define B_INMEM 0x00001 /* in-memory tree */ 411 #define B_METADIRTY 0x00002 /* need to write metadata */ 412 #define B_MODIFIED 0x00004 /* tree modified */ 413 #define B_NEEDSWAP 0x00008 /* if byte order requires swapping */ 414 #define B_RDONLY 0x00010 /* read-only tree */ 415 416 #define B_NODUPS 0x00020 /* no duplicate keys permitted */ 417 #define R_RECNO 0x00080 /* record oriented tree */ 418 419 #define R_CLOSEFP 0x00040 /* opened a file pointer */ 420 #define R_EOF 0x00100 /* end of input file reached. */ 421 #define R_FIXLEN 0x00200 /* fixed length records */ 422 #define R_MEMMAPPED 0x00400 /* memory mapped file. */ 423 #define R_INMEM 0x00800 /* in-memory file */ 424 #define R_MODIFIED 0x01000 /* modified file */ 425 #define R_RDONLY 0x02000 /* read-only file */ 426 427 #define B_DB_LOCK 0x04000 /* DB_LOCK specified. */ 428 #define B_DB_SHMEM 0x08000 /* DB_SHMEM specified. */ 429 #define B_DB_TXN 0x10000 /* DB_TXN specified. */ 430 uint32_t flags; 431 } BTREE; 432 433 #include "extern.h" 434
Indexes created Sat Sep 20 22:09:52 GMT 2025