1 /*- 2 * Copyright (c) 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Mike Olson. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)btree.h 8.11 (Berkeley) 8/17/94 37 * $DragonFly: src/lib/libc/db/btree/btree.h,v 1.3 2003/11/12 20:21:22 eirikn Exp $ 38 */ 39 40 /* Macros to set/clear/test flags. */ 41 #define F_SET(p, f) (p)->flags |= (f) 42 #define F_CLR(p, f) (p)->flags &= ~(f) 43 #define F_ISSET(p, f) ((p)->flags & (f)) 44 45 #include <mpool.h> 46 47 #define DEFMINKEYPAGE (2) /* Minimum keys per page */ 48 #define MINCACHE (5) /* Minimum cached pages */ 49 #define MINPSIZE (512) /* Minimum page size */ 50 51 /* 52 * Page 0 of a btree file contains a copy of the meta-data. This page is also 53 * used as an out-of-band page, i.e. page pointers that point to nowhere point 54 * to page 0. Page 1 is the root of the btree. 55 */ 56 #define P_INVALID 0 /* Invalid tree page number. */ 57 #define P_META 0 /* Tree metadata page number. */ 58 #define P_ROOT 1 /* Tree root page number. */ 59 60 /* 61 * There are five page layouts in the btree: btree internal pages (BINTERNAL), 62 * btree leaf pages (BLEAF), recno internal pages (RINTERNAL), recno leaf pages 63 * (RLEAF) and overflow pages. All five page types have a page header (PAGE). 64 * This implementation requires that values within structures NOT be padded. 65 * (ANSI C permits random padding.) If your compiler pads randomly you'll have 66 * to do some work to get this package to run. 67 */ 68 typedef struct _page { 69 pgno_t pgno; /* this page's page number */ 70 pgno_t prevpg; /* left sibling */ 71 pgno_t nextpg; /* right sibling */ 72 73 #define P_BINTERNAL 0x01 /* btree internal page */ 74 #define P_BLEAF 0x02 /* leaf page */ 75 #define P_OVERFLOW 0x04 /* overflow page */ 76 #define P_RINTERNAL 0x08 /* recno internal page */ 77 #define P_RLEAF 0x10 /* leaf page */ 78 #define P_TYPE 0x1f /* type mask */ 79 #define P_PRESERVE 0x20 /* never delete this chain of pages */ 80 u_int32_t flags; 81 82 indx_t lower; /* lower bound of free space on page */ 83 indx_t upper; /* upper bound of free space on page */ 84 indx_t linp[1]; /* indx_t-aligned VAR. LENGTH DATA */ 85 } PAGE; 86 87 /* First and next index. */ 88 #define BTDATAOFF \ 89 (sizeof(pgno_t) + sizeof(pgno_t) + sizeof(pgno_t) + \ 90 sizeof(u_int32_t) + sizeof(indx_t) + sizeof(indx_t)) 91 #define NEXTINDEX(p) (((p)->lower - BTDATAOFF) / sizeof(indx_t)) 92 93 /* 94 * For pages other than overflow pages, there is an array of offsets into the 95 * rest of the page immediately following the page header. Each offset is to 96 * an item which is unique to the type of page. The h_lower offset is just 97 * past the last filled-in index. The h_upper offset is the first item on the 98 * page. Offsets are from the beginning of the page. 99 * 100 * If an item is too big to store on a single page, a flag is set and the item 101 * is a { page, size } pair such that the page is the first page of an overflow 102 * chain with size bytes of item. Overflow pages are simply bytes without any 103 * external structure. 104 * 105 * The page number and size fields in the items are pgno_t-aligned so they can 106 * be manipulated without copying. (This presumes that 32 bit items can be 107 * manipulated on this system.) 108 */ 109 #define LALIGN(n) (((n) + sizeof(pgno_t) - 1) & ~(sizeof(pgno_t) - 1)) 110 #define NOVFLSIZE (sizeof(pgno_t) + sizeof(u_int32_t)) 111 112 /* 113 * For the btree internal pages, the item is a key. BINTERNALs are {key, pgno} 114 * pairs, such that the key compares less than or equal to all of the records 115 * on that page. For a tree without duplicate keys, an internal page with two 116 * consecutive keys, a and b, will have all records greater than or equal to a 117 * and less than b stored on the page associated with a. Duplicate keys are 118 * somewhat special and can cause duplicate internal and leaf page records and 119 * some minor modifications of the above rule. 120 */ 121 typedef struct _binternal { 122 u_int32_t ksize; /* key size */ 123 pgno_t pgno; /* page number stored on */ 124 #define P_BIGDATA 0x01 /* overflow data */ 125 #define P_BIGKEY 0x02 /* overflow key */ 126 u_char flags; 127 char bytes[1]; /* data */ 128 } BINTERNAL; 129 130 /* Get the page's BINTERNAL structure at index indx. */ 131 #define GETBINTERNAL(pg, indx) \ 132 ((BINTERNAL *)((char *)(pg) + (pg)->linp[indx])) 133 134 /* Get the number of bytes in the entry. */ 135 #define NBINTERNAL(len) \ 136 LALIGN(sizeof(u_int32_t) + sizeof(pgno_t) + sizeof(u_char) + (len)) 137 138 /* Copy a BINTERNAL entry to the page. */ 139 #define WR_BINTERNAL(p, size, pgno, flags) { \ 140 *(u_int32_t *)p = size; \ 141 p += sizeof(u_int32_t); \ 142 *(pgno_t *)p = pgno; \ 143 p += sizeof(pgno_t); \ 144 *(u_char *)p = flags; \ 145 p += sizeof(u_char); \ 146 } 147 148 /* 149 * For the recno internal pages, the item is a page number with the number of 150 * keys found on that page and below. 151 */ 152 typedef struct _rinternal { 153 recno_t nrecs; /* number of records */ 154 pgno_t pgno; /* page number stored below */ 155 } RINTERNAL; 156 157 /* Get the page's RINTERNAL structure at index indx. */ 158 #define GETRINTERNAL(pg, indx) \ 159 ((RINTERNAL *)((char *)(pg) + (pg)->linp[indx])) 160 161 /* Get the number of bytes in the entry. */ 162 #define NRINTERNAL \ 163 LALIGN(sizeof(recno_t) + sizeof(pgno_t)) 164 165 /* Copy a RINTERAL entry to the page. */ 166 #define WR_RINTERNAL(p, nrecs, pgno) { \ 167 *(recno_t *)p = nrecs; \ 168 p += sizeof(recno_t); \ 169 *(pgno_t *)p = pgno; \ 170 } 171 172 /* For the btree leaf pages, the item is a key and data pair. */ 173 typedef struct _bleaf { 174 u_int32_t ksize; /* size of key */ 175 u_int32_t dsize; /* size of data */ 176 u_char flags; /* P_BIGDATA, P_BIGKEY */ 177 char bytes[1]; /* data */ 178 } BLEAF; 179 180 /* Get the page's BLEAF structure at index indx. */ 181 #define GETBLEAF(pg, indx) \ 182 ((BLEAF *)((char *)(pg) + (pg)->linp[indx])) 183 184 /* Get the number of bytes in the entry. */ 185 #define NBLEAF(p) NBLEAFDBT((p)->ksize, (p)->dsize) 186 187 /* Get the number of bytes in the user's key/data pair. */ 188 #define NBLEAFDBT(ksize, dsize) \ 189 LALIGN(sizeof(u_int32_t) + sizeof(u_int32_t) + sizeof(u_char) + \ 190 (ksize) + (dsize)) 191 192 /* Copy a BLEAF entry to the page. */ 193 #define WR_BLEAF(p, key, data, flags) { \ 194 *(u_int32_t *)p = key->size; \ 195 p += sizeof(u_int32_t); \ 196 *(u_int32_t *)p = data->size; \ 197 p += sizeof(u_int32_t); \ 198 *(u_char *)p = flags; \ 199 p += sizeof(u_char); \ 200 memmove(p, key->data, key->size); \ 201 p += key->size; \ 202 memmove(p, data->data, data->size); \ 203 } 204 205 /* For the recno leaf pages, the item is a data entry. */ 206 typedef struct _rleaf { 207 u_int32_t dsize; /* size of data */ 208 u_char flags; /* P_BIGDATA */ 209 char bytes[1]; 210 } RLEAF; 211 212 /* Get the page's RLEAF structure at index indx. */ 213 #define GETRLEAF(pg, indx) \ 214 ((RLEAF *)((char *)(pg) + (pg)->linp[indx])) 215 216 /* Get the number of bytes in the entry. */ 217 #define NRLEAF(p) NRLEAFDBT((p)->dsize) 218 219 /* Get the number of bytes from the user's data. */ 220 #define NRLEAFDBT(dsize) \ 221 LALIGN(sizeof(u_int32_t) + sizeof(u_char) + (dsize)) 222 223 /* Copy a RLEAF entry to the page. */ 224 #define WR_RLEAF(p, data, flags) { \ 225 *(u_int32_t *)p = data->size; \ 226 p += sizeof(u_int32_t); \ 227 *(u_char *)p = flags; \ 228 p += sizeof(u_char); \ 229 memmove(p, data->data, data->size); \ 230 } 231 232 /* 233 * A record in the tree is either a pointer to a page and an index in the page 234 * or a page number and an index. These structures are used as a cursor, stack 235 * entry and search returns as well as to pass records to other routines. 236 * 237 * One comment about searches. Internal page searches must find the largest 238 * record less than key in the tree so that descents work. Leaf page searches 239 * must find the smallest record greater than key so that the returned index 240 * is the record's correct position for insertion. 241 */ 242 typedef struct _epgno { 243 pgno_t pgno; /* the page number */ 244 indx_t index; /* the index on the page */ 245 } EPGNO; 246 247 typedef struct _epg { 248 PAGE *page; /* the (pinned) page */ 249 indx_t index; /* the index on the page */ 250 } EPG; 251 252 /* 253 * About cursors. The cursor (and the page that contained the key/data pair 254 * that it referenced) can be deleted, which makes things a bit tricky. If 255 * there are no duplicates of the cursor key in the tree (i.e. B_NODUPS is set 256 * or there simply aren't any duplicates of the key) we copy the key that it 257 * referenced when it's deleted, and reacquire a new cursor key if the cursor 258 * is used again. If there are duplicates keys, we move to the next/previous 259 * key, and set a flag so that we know what happened. NOTE: if duplicate (to 260 * the cursor) keys are added to the tree during this process, it is undefined 261 * if they will be returned or not in a cursor scan. 262 * 263 * The flags determine the possible states of the cursor: 264 * 265 * CURS_INIT The cursor references *something*. 266 * CURS_ACQUIRE The cursor was deleted, and a key has been saved so that 267 * we can reacquire the right position in the tree. 268 * CURS_AFTER, CURS_BEFORE 269 * The cursor was deleted, and now references a key/data pair 270 * that has not yet been returned, either before or after the 271 * deleted key/data pair. 272 * XXX 273 * This structure is broken out so that we can eventually offer multiple 274 * cursors as part of the DB interface. 275 */ 276 typedef struct _cursor { 277 EPGNO pg; /* B: Saved tree reference. */ 278 DBT key; /* B: Saved key, or key.data == NULL. */ 279 recno_t rcursor; /* R: recno cursor (1-based) */ 280 281 #define CURS_ACQUIRE 0x01 /* B: Cursor needs to be reacquired. */ 282 #define CURS_AFTER 0x02 /* B: Unreturned cursor after key. */ 283 #define CURS_BEFORE 0x04 /* B: Unreturned cursor before key. */ 284 #define CURS_INIT 0x08 /* RB: Cursor initialized. */ 285 u_int8_t flags; 286 } CURSOR; 287 288 /* 289 * The metadata of the tree. The nrecs field is used only by the RECNO code. 290 * This is because the btree doesn't really need it and it requires that every 291 * put or delete call modify the metadata. 292 */ 293 typedef struct _btmeta { 294 u_int32_t magic; /* magic number */ 295 u_int32_t version; /* version */ 296 u_int32_t psize; /* page size */ 297 u_int32_t free; /* page number of first free page */ 298 u_int32_t nrecs; /* R: number of records */ 299 300 #define SAVEMETA (B_NODUPS | R_RECNO) 301 u_int32_t flags; /* bt_flags & SAVEMETA */ 302 } BTMETA; 303 304 /* The in-memory btree/recno data structure. */ 305 typedef struct _btree { 306 MPOOL *bt_mp; /* memory pool cookie */ 307 308 DB *bt_dbp; /* pointer to enclosing DB */ 309 310 EPG bt_cur; /* current (pinned) page */ 311 PAGE *bt_pinned; /* page pinned across calls */ 312 313 CURSOR bt_cursor; /* cursor */ 314 315 #define BT_PUSH(t, p, i) { \ 316 t->bt_sp->pgno = p; \ 317 t->bt_sp->index = i; \ 318 ++t->bt_sp; \ 319 } 320 #define BT_POP(t) (t->bt_sp == t->bt_stack ? NULL : --t->bt_sp) 321 #define BT_CLR(t) (t->bt_sp = t->bt_stack) 322 EPGNO bt_stack[50]; /* stack of parent pages */ 323 EPGNO *bt_sp; /* current stack pointer */ 324 325 DBT bt_rkey; /* returned key */ 326 DBT bt_rdata; /* returned data */ 327 328 int bt_fd; /* tree file descriptor */ 329 330 pgno_t bt_free; /* next free page */ 331 u_int32_t bt_psize; /* page size */ 332 indx_t bt_ovflsize; /* cut-off for key/data overflow */ 333 int bt_lorder; /* byte order */ 334 /* sorted order */ 335 enum { NOT, BACK, FORWARD } bt_order; 336 EPGNO bt_last; /* last insert */ 337 338 /* B: key comparison function */ 339 int (*bt_cmp) (const DBT *, const DBT *); 340 /* B: prefix comparison function */ 341 size_t (*bt_pfx) (const DBT *, const DBT *); 342 /* R: recno input function */ 343 int (*bt_irec) (struct _btree *, recno_t); 344 345 FILE *bt_rfp; /* R: record FILE pointer */ 346 int bt_rfd; /* R: record file descriptor */ 347 348 caddr_t bt_cmap; /* R: current point in mapped space */ 349 caddr_t bt_smap; /* R: start of mapped space */ 350 caddr_t bt_emap; /* R: end of mapped space */ 351 size_t bt_msize; /* R: size of mapped region. */ 352 353 recno_t bt_nrecs; /* R: number of records */ 354 size_t bt_reclen; /* R: fixed record length */ 355 u_char bt_bval; /* R: delimiting byte/pad character */ 356 357 /* 358 * NB: 359 * B_NODUPS and R_RECNO are stored on disk, and may not be changed. 360 */ 361 #define B_INMEM 0x00001 /* in-memory tree */ 362 #define B_METADIRTY 0x00002 /* need to write metadata */ 363 #define B_MODIFIED 0x00004 /* tree modified */ 364 #define B_NEEDSWAP 0x00008 /* if byte order requires swapping */ 365 #define B_RDONLY 0x00010 /* read-only tree */ 366 367 #define B_NODUPS 0x00020 /* no duplicate keys permitted */ 368 #define R_RECNO 0x00080 /* record oriented tree */ 369 370 #define R_CLOSEFP 0x00040 /* opened a file pointer */ 371 #define R_EOF 0x00100 /* end of input file reached. */ 372 #define R_FIXLEN 0x00200 /* fixed length records */ 373 #define R_MEMMAPPED 0x00400 /* memory mapped file. */ 374 #define R_INMEM 0x00800 /* in-memory file */ 375 #define R_MODIFIED 0x01000 /* modified file */ 376 #define R_RDONLY 0x02000 /* read-only file */ 377 378 #define B_DB_LOCK 0x04000 /* DB_LOCK specified. */ 379 #define B_DB_SHMEM 0x08000 /* DB_SHMEM specified. */ 380 #define B_DB_TXN 0x10000 /* DB_TXN specified. */ 381 u_int32_t flags; 382 } BTREE; 383 384 #include "extern.h" 385