Commit | Line | Data |
---|---|---|
463ee0b2 LW |
1 | /* |
2 | * sdbm - ndbm work-alike hashed database library | |
3 | * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). | |
4 | * author: oz@nexus.yorku.ca | |
5 | * status: public domain. | |
6 | * | |
7 | * core routines | |
8 | */ | |
9 | ||
17f28c40 | 10 | #include "INTERN.h" |
85e6fe83 | 11 | #include "config.h" |
4f63d024 GS |
12 | #ifdef WIN32 |
13 | #include "io.h" | |
14 | #endif | |
463ee0b2 LW |
15 | #include "sdbm.h" |
16 | #include "tune.h" | |
17 | #include "pair.h" | |
18 | ||
85e6fe83 LW |
19 | #ifdef I_FCNTL |
20 | # include <fcntl.h> | |
463ee0b2 | 21 | #endif |
85e6fe83 LW |
22 | #ifdef I_SYS_FILE |
23 | # include <sys/file.h> | |
463ee0b2 LW |
24 | #endif |
25 | ||
85e6fe83 | 26 | #ifdef I_STRING |
89e79dea JH |
27 | # ifndef __ultrix__ |
28 | # include <string.h> | |
29 | # endif | |
85e6fe83 LW |
30 | #else |
31 | # include <strings.h> | |
463ee0b2 LW |
32 | #endif |
33 | ||
34 | /* | |
35 | * externals | |
36 | */ | |
137443ea | 37 | #ifndef WIN32 |
463ee0b2 LW |
38 | #ifndef sun |
39 | extern int errno; | |
40 | #endif | |
a5b1c163 | 41 | #endif |
463ee0b2 | 42 | |
85e6fe83 | 43 | extern Malloc_t malloc proto((MEM_SIZE)); |
851efeba | 44 | extern Free_t free proto((Malloc_t)); |
bf0c440f | 45 | |
463ee0b2 LW |
46 | /* |
47 | * forward | |
48 | */ | |
49 | static int getdbit proto((DBM *, long)); | |
50 | static int setdbit proto((DBM *, long)); | |
51 | static int getpage proto((DBM *, long)); | |
52 | static datum getnext proto((DBM *)); | |
53 | static int makroom proto((DBM *, long, int)); | |
54 | ||
55 | /* | |
56 | * useful macros | |
57 | */ | |
58 | #define bad(x) ((x).dptr == NULL || (x).dsize < 0) | |
59 | #define exhash(item) sdbm_hash((item).dptr, (item).dsize) | |
60 | #define ioerr(db) ((db)->flags |= DBM_IOERR) | |
61 | ||
62 | #define OFF_PAG(off) (long) (off) * PBLKSIZ | |
63 | #define OFF_DIR(off) (long) (off) * DBLKSIZ | |
64 | ||
65 | static long masks[] = { | |
66 | 000000000000, 000000000001, 000000000003, 000000000007, | |
67 | 000000000017, 000000000037, 000000000077, 000000000177, | |
68 | 000000000377, 000000000777, 000000001777, 000000003777, | |
69 | 000000007777, 000000017777, 000000037777, 000000077777, | |
70 | 000000177777, 000000377777, 000000777777, 000001777777, | |
71 | 000003777777, 000007777777, 000017777777, 000037777777, | |
72 | 000077777777, 000177777777, 000377777777, 000777777777, | |
73 | 001777777777, 003777777777, 007777777777, 017777777777 | |
74 | }; | |
75 | ||
463ee0b2 | 76 | DBM * |
f0f333f4 | 77 | sdbm_open(register char *file, register int flags, register int mode) |
463ee0b2 LW |
78 | { |
79 | register DBM *db; | |
80 | register char *dirname; | |
81 | register char *pagname; | |
82 | register int n; | |
83 | ||
84 | if (file == NULL || !*file) | |
85 | return errno = EINVAL, (DBM *) NULL; | |
86 | /* | |
87 | * need space for two seperate filenames | |
88 | */ | |
89 | n = strlen(file) * 2 + strlen(DIRFEXT) + strlen(PAGFEXT) + 2; | |
90 | ||
f0f333f4 | 91 | if ((dirname = (char *) malloc((unsigned) n)) == NULL) |
463ee0b2 LW |
92 | return errno = ENOMEM, (DBM *) NULL; |
93 | /* | |
94 | * build the file names | |
95 | */ | |
96 | dirname = strcat(strcpy(dirname, file), DIRFEXT); | |
97 | pagname = strcpy(dirname + strlen(dirname) + 1, file); | |
98 | pagname = strcat(pagname, PAGFEXT); | |
99 | ||
100 | db = sdbm_prep(dirname, pagname, flags, mode); | |
101 | free((char *) dirname); | |
102 | return db; | |
103 | } | |
104 | ||
105 | DBM * | |
f0f333f4 | 106 | sdbm_prep(char *dirname, char *pagname, int flags, int mode) |
463ee0b2 LW |
107 | { |
108 | register DBM *db; | |
109 | struct stat dstat; | |
110 | ||
111 | if ((db = (DBM *) malloc(sizeof(DBM))) == NULL) | |
112 | return errno = ENOMEM, (DBM *) NULL; | |
113 | ||
114 | db->flags = 0; | |
115 | db->hmask = 0; | |
116 | db->blkptr = 0; | |
117 | db->keyptr = 0; | |
118 | /* | |
119 | * adjust user flags so that WRONLY becomes RDWR, | |
120 | * as required by this package. Also set our internal | |
121 | * flag for RDONLY if needed. | |
122 | */ | |
123 | if (flags & O_WRONLY) | |
124 | flags = (flags & ~O_WRONLY) | O_RDWR; | |
125 | ||
126 | else if ((flags & 03) == O_RDONLY) | |
127 | db->flags = DBM_RDONLY; | |
128 | /* | |
129 | * open the files in sequence, and stat the dirfile. | |
130 | * If we fail anywhere, undo everything, return NULL. | |
131 | */ | |
1761cee5 | 132 | #if defined(OS2) || defined(MSDOS) || defined(WIN32) || defined(__CYGWIN__) |
4633a7c4 LW |
133 | flags |= O_BINARY; |
134 | # endif | |
463ee0b2 LW |
135 | if ((db->pagf = open(pagname, flags, mode)) > -1) { |
136 | if ((db->dirf = open(dirname, flags, mode)) > -1) { | |
137 | /* | |
138 | * need the dirfile size to establish max bit number. | |
139 | */ | |
140 | if (fstat(db->dirf, &dstat) == 0) { | |
141 | /* | |
142 | * zero size: either a fresh database, or one with a single, | |
143 | * unsplit data page: dirpage is all zeros. | |
144 | */ | |
145 | db->dirbno = (!dstat.st_size) ? 0 : -1; | |
146 | db->pagbno = -1; | |
147 | db->maxbno = dstat.st_size * BYTESIZ; | |
148 | ||
149 | (void) memset(db->pagbuf, 0, PBLKSIZ); | |
150 | (void) memset(db->dirbuf, 0, DBLKSIZ); | |
151 | /* | |
152 | * success | |
153 | */ | |
154 | return db; | |
155 | } | |
156 | (void) close(db->dirf); | |
157 | } | |
158 | (void) close(db->pagf); | |
159 | } | |
160 | free((char *) db); | |
161 | return (DBM *) NULL; | |
162 | } | |
163 | ||
164 | void | |
f0f333f4 | 165 | sdbm_close(register DBM *db) |
463ee0b2 LW |
166 | { |
167 | if (db == NULL) | |
168 | errno = EINVAL; | |
169 | else { | |
170 | (void) close(db->dirf); | |
171 | (void) close(db->pagf); | |
172 | free((char *) db); | |
173 | } | |
174 | } | |
175 | ||
176 | datum | |
f0f333f4 | 177 | sdbm_fetch(register DBM *db, datum key) |
463ee0b2 LW |
178 | { |
179 | if (db == NULL || bad(key)) | |
180 | return errno = EINVAL, nullitem; | |
181 | ||
182 | if (getpage(db, exhash(key))) | |
183 | return getpair(db->pagbuf, key); | |
184 | ||
185 | return ioerr(db), nullitem; | |
186 | } | |
187 | ||
188 | int | |
f4b9d880 RA |
189 | sdbm_exists(register DBM *db, datum key) |
190 | { | |
191 | if (db == NULL || bad(key)) | |
192 | return errno = EINVAL, -1; | |
193 | ||
194 | if (getpage(db, exhash(key))) | |
195 | return exipair(db->pagbuf, key); | |
196 | ||
197 | return ioerr(db), -1; | |
198 | } | |
199 | ||
200 | int | |
f0f333f4 | 201 | sdbm_delete(register DBM *db, datum key) |
463ee0b2 LW |
202 | { |
203 | if (db == NULL || bad(key)) | |
204 | return errno = EINVAL, -1; | |
205 | if (sdbm_rdonly(db)) | |
206 | return errno = EPERM, -1; | |
207 | ||
208 | if (getpage(db, exhash(key))) { | |
209 | if (!delpair(db->pagbuf, key)) | |
210 | return -1; | |
211 | /* | |
212 | * update the page file | |
213 | */ | |
214 | if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 | |
215 | || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
216 | return ioerr(db), -1; | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
221 | return ioerr(db), -1; | |
222 | } | |
223 | ||
224 | int | |
f0f333f4 | 225 | sdbm_store(register DBM *db, datum key, datum val, int flags) |
463ee0b2 LW |
226 | { |
227 | int need; | |
228 | register long hash; | |
229 | ||
230 | if (db == NULL || bad(key)) | |
231 | return errno = EINVAL, -1; | |
232 | if (sdbm_rdonly(db)) | |
233 | return errno = EPERM, -1; | |
234 | ||
235 | need = key.dsize + val.dsize; | |
236 | /* | |
237 | * is the pair too big (or too small) for this database ?? | |
238 | */ | |
239 | if (need < 0 || need > PAIRMAX) | |
240 | return errno = EINVAL, -1; | |
241 | ||
242 | if (getpage(db, (hash = exhash(key)))) { | |
243 | /* | |
244 | * if we need to replace, delete the key/data pair | |
245 | * first. If it is not there, ignore. | |
246 | */ | |
247 | if (flags == DBM_REPLACE) | |
248 | (void) delpair(db->pagbuf, key); | |
249 | #ifdef SEEDUPS | |
250 | else if (duppair(db->pagbuf, key)) | |
251 | return 1; | |
252 | #endif | |
253 | /* | |
254 | * if we do not have enough room, we have to split. | |
255 | */ | |
256 | if (!fitpair(db->pagbuf, need)) | |
257 | if (!makroom(db, hash, need)) | |
258 | return ioerr(db), -1; | |
259 | /* | |
260 | * we have enough room or split is successful. insert the key, | |
261 | * and update the page file. | |
262 | */ | |
263 | (void) putpair(db->pagbuf, key, val); | |
264 | ||
265 | if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 | |
266 | || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
267 | return ioerr(db), -1; | |
268 | /* | |
269 | * success | |
270 | */ | |
271 | return 0; | |
272 | } | |
273 | ||
274 | return ioerr(db), -1; | |
275 | } | |
276 | ||
277 | /* | |
278 | * makroom - make room by splitting the overfull page | |
279 | * this routine will attempt to make room for SPLTMAX times before | |
280 | * giving up. | |
281 | */ | |
282 | static int | |
f0f333f4 | 283 | makroom(register DBM *db, long int hash, int need) |
463ee0b2 LW |
284 | { |
285 | long newp; | |
286 | char twin[PBLKSIZ]; | |
f6bbbfc7 NS |
287 | #if defined(DOSISH) || defined(WIN32) |
288 | char zer[PBLKSIZ]; | |
289 | long oldtail; | |
290 | #endif | |
463ee0b2 | 291 | char *pag = db->pagbuf; |
f0f333f4 | 292 | char *New = twin; |
463ee0b2 LW |
293 | register int smax = SPLTMAX; |
294 | ||
295 | do { | |
296 | /* | |
297 | * split the current page | |
298 | */ | |
f0f333f4 | 299 | (void) splpage(pag, New, db->hmask + 1); |
463ee0b2 LW |
300 | /* |
301 | * address of the new page | |
302 | */ | |
303 | newp = (hash & db->hmask) | (db->hmask + 1); | |
304 | ||
305 | /* | |
306 | * write delay, read avoidence/cache shuffle: | |
307 | * select the page for incoming pair: if key is to go to the new page, | |
308 | * write out the previous one, and copy the new one over, thus making | |
309 | * it the current page. If not, simply write the new page, and we are | |
310 | * still looking at the page of interest. current page is not updated | |
311 | * here, as sdbm_store will do so, after it inserts the incoming pair. | |
312 | */ | |
f6bbbfc7 NS |
313 | |
314 | #if defined(DOSISH) || defined(WIN32) | |
315 | /* | |
316 | * Fill hole with 0 if made it. | |
317 | * (hole is NOT read as 0) | |
318 | */ | |
319 | oldtail = lseek(db->pagf, 0L, SEEK_END); | |
320 | memset(zer, 0, PBLKSIZ); | |
321 | while (OFF_PAG(newp) > oldtail) { | |
322 | if (lseek(db->pagf, 0L, SEEK_END) < 0 || | |
323 | write(db->pagf, zer, PBLKSIZ) < 0) { | |
324 | ||
325 | return 0; | |
326 | } | |
327 | oldtail += PBLKSIZ; | |
328 | } | |
329 | #endif | |
463ee0b2 LW |
330 | if (hash & (db->hmask + 1)) { |
331 | if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 | |
332 | || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
333 | return 0; | |
334 | db->pagbno = newp; | |
f0f333f4 | 335 | (void) memcpy(pag, New, PBLKSIZ); |
463ee0b2 LW |
336 | } |
337 | else if (lseek(db->pagf, OFF_PAG(newp), SEEK_SET) < 0 | |
f0f333f4 | 338 | || write(db->pagf, New, PBLKSIZ) < 0) |
463ee0b2 LW |
339 | return 0; |
340 | ||
341 | if (!setdbit(db, db->curbit)) | |
342 | return 0; | |
343 | /* | |
344 | * see if we have enough room now | |
345 | */ | |
346 | if (fitpair(pag, need)) | |
347 | return 1; | |
348 | /* | |
349 | * try again... update curbit and hmask as getpage would have | |
350 | * done. because of our update of the current page, we do not | |
351 | * need to read in anything. BUT we have to write the current | |
352 | * [deferred] page out, as the window of failure is too great. | |
353 | */ | |
354 | db->curbit = 2 * db->curbit + | |
355 | ((hash & (db->hmask + 1)) ? 2 : 1); | |
356 | db->hmask |= db->hmask + 1; | |
357 | ||
358 | if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 | |
359 | || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
360 | return 0; | |
361 | ||
362 | } while (--smax); | |
363 | /* | |
364 | * if we are here, this is real bad news. After SPLTMAX splits, | |
365 | * we still cannot fit the key. say goodnight. | |
366 | */ | |
367 | #ifdef BADMESS | |
368 | (void) write(2, "sdbm: cannot insert after SPLTMAX attempts.\n", 44); | |
369 | #endif | |
370 | return 0; | |
371 | ||
372 | } | |
373 | ||
374 | /* | |
375 | * the following two routines will break if | |
376 | * deletions aren't taken into account. (ndbm bug) | |
377 | */ | |
378 | datum | |
f0f333f4 | 379 | sdbm_firstkey(register DBM *db) |
463ee0b2 LW |
380 | { |
381 | if (db == NULL) | |
382 | return errno = EINVAL, nullitem; | |
383 | /* | |
384 | * start at page 0 | |
385 | */ | |
386 | if (lseek(db->pagf, OFF_PAG(0), SEEK_SET) < 0 | |
387 | || read(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
388 | return ioerr(db), nullitem; | |
389 | db->pagbno = 0; | |
390 | db->blkptr = 0; | |
391 | db->keyptr = 0; | |
392 | ||
393 | return getnext(db); | |
394 | } | |
395 | ||
396 | datum | |
f0f333f4 | 397 | sdbm_nextkey(register DBM *db) |
463ee0b2 LW |
398 | { |
399 | if (db == NULL) | |
400 | return errno = EINVAL, nullitem; | |
401 | return getnext(db); | |
402 | } | |
403 | ||
404 | /* | |
405 | * all important binary trie traversal | |
406 | */ | |
407 | static int | |
f0f333f4 | 408 | getpage(register DBM *db, register long int hash) |
463ee0b2 LW |
409 | { |
410 | register int hbit; | |
411 | register long dbit; | |
412 | register long pagb; | |
413 | ||
414 | dbit = 0; | |
415 | hbit = 0; | |
416 | while (dbit < db->maxbno && getdbit(db, dbit)) | |
417 | dbit = 2 * dbit + ((hash & (1 << hbit++)) ? 2 : 1); | |
418 | ||
419 | debug(("dbit: %d...", dbit)); | |
420 | ||
421 | db->curbit = dbit; | |
422 | db->hmask = masks[hbit]; | |
423 | ||
424 | pagb = hash & db->hmask; | |
425 | /* | |
426 | * see if the block we need is already in memory. | |
427 | * note: this lookaside cache has about 10% hit rate. | |
428 | */ | |
429 | if (pagb != db->pagbno) { | |
430 | /* | |
431 | * note: here, we assume a "hole" is read as 0s. | |
432 | * if not, must zero pagbuf first. | |
433 | */ | |
434 | if (lseek(db->pagf, OFF_PAG(pagb), SEEK_SET) < 0 | |
435 | || read(db->pagf, db->pagbuf, PBLKSIZ) < 0) | |
436 | return 0; | |
437 | if (!chkpage(db->pagbuf)) | |
438 | return 0; | |
439 | db->pagbno = pagb; | |
440 | ||
441 | debug(("pag read: %d\n", pagb)); | |
442 | } | |
443 | return 1; | |
444 | } | |
445 | ||
446 | static int | |
f0f333f4 | 447 | getdbit(register DBM *db, register long int dbit) |
463ee0b2 LW |
448 | { |
449 | register long c; | |
450 | register long dirb; | |
451 | ||
452 | c = dbit / BYTESIZ; | |
453 | dirb = c / DBLKSIZ; | |
454 | ||
455 | if (dirb != db->dirbno) { | |
98627ae8 | 456 | int got; |
463ee0b2 | 457 | if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 |
98627ae8 | 458 | || (got=read(db->dirf, db->dirbuf, DBLKSIZ)) < 0) |
463ee0b2 | 459 | return 0; |
98627ae8 GS |
460 | if (got==0) |
461 | memset(db->dirbuf,0,DBLKSIZ); | |
463ee0b2 LW |
462 | db->dirbno = dirb; |
463 | ||
464 | debug(("dir read: %d\n", dirb)); | |
465 | } | |
466 | ||
467 | return db->dirbuf[c % DBLKSIZ] & (1 << dbit % BYTESIZ); | |
468 | } | |
469 | ||
470 | static int | |
f0f333f4 | 471 | setdbit(register DBM *db, register long int dbit) |
463ee0b2 LW |
472 | { |
473 | register long c; | |
474 | register long dirb; | |
475 | ||
476 | c = dbit / BYTESIZ; | |
477 | dirb = c / DBLKSIZ; | |
478 | ||
479 | if (dirb != db->dirbno) { | |
98627ae8 | 480 | int got; |
463ee0b2 | 481 | if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 |
98627ae8 | 482 | || (got=read(db->dirf, db->dirbuf, DBLKSIZ)) < 0) |
463ee0b2 | 483 | return 0; |
98627ae8 GS |
484 | if (got==0) |
485 | memset(db->dirbuf,0,DBLKSIZ); | |
463ee0b2 LW |
486 | db->dirbno = dirb; |
487 | ||
488 | debug(("dir read: %d\n", dirb)); | |
489 | } | |
490 | ||
491 | db->dirbuf[c % DBLKSIZ] |= (1 << dbit % BYTESIZ); | |
492 | ||
98627ae8 | 493 | #if 0 |
463ee0b2 LW |
494 | if (dbit >= db->maxbno) |
495 | db->maxbno += DBLKSIZ * BYTESIZ; | |
98627ae8 GS |
496 | #else |
497 | if (OFF_DIR((dirb+1))*BYTESIZ > db->maxbno) | |
498 | db->maxbno=OFF_DIR((dirb+1))*BYTESIZ; | |
499 | #endif | |
463ee0b2 LW |
500 | |
501 | if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 | |
502 | || write(db->dirf, db->dirbuf, DBLKSIZ) < 0) | |
503 | return 0; | |
504 | ||
505 | return 1; | |
506 | } | |
507 | ||
508 | /* | |
509 | * getnext - get the next key in the page, and if done with | |
510 | * the page, try the next page in sequence | |
511 | */ | |
512 | static datum | |
f0f333f4 | 513 | getnext(register DBM *db) |
463ee0b2 LW |
514 | { |
515 | datum key; | |
516 | ||
517 | for (;;) { | |
518 | db->keyptr++; | |
519 | key = getnkey(db->pagbuf, db->keyptr); | |
520 | if (key.dptr != NULL) | |
521 | return key; | |
522 | /* | |
523 | * we either run out, or there is nothing on this page.. | |
524 | * try the next one... If we lost our position on the | |
525 | * file, we will have to seek. | |
526 | */ | |
527 | db->keyptr = 0; | |
528 | if (db->pagbno != db->blkptr++) | |
529 | if (lseek(db->pagf, OFF_PAG(db->blkptr), SEEK_SET) < 0) | |
530 | break; | |
531 | db->pagbno = db->blkptr; | |
532 | if (read(db->pagf, db->pagbuf, PBLKSIZ) <= 0) | |
533 | break; | |
534 | if (!chkpage(db->pagbuf)) | |
535 | break; | |
536 | } | |
537 | ||
538 | return ioerr(db), nullitem; | |
539 | } | |
85e6fe83 | 540 |