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 */ 405