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1 | /* $Header: hash.c,v 3.0.1.3 90/03/27 15:59:09 lwall Locked $ |
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2 | * |
3 | * Copyright (c) 1989, Larry Wall |
4 | * |
5 | * You may distribute under the terms of the GNU General Public License |
6 | * as specified in the README file that comes with the perl 3.0 kit. |
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7 | * |
8 | * $Log: hash.c,v $ |
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9 | * Revision 3.0.1.3 90/03/27 15:59:09 lwall |
10 | * patch16: @dbmvalues{'foo','bar'} could use the same cache entry for both values |
11 | * |
663a0e37 |
12 | * Revision 3.0.1.2 89/12/21 20:03:39 lwall |
13 | * patch7: errno may now be a macro with an lvalue |
14 | * |
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15 | * Revision 3.0.1.1 89/11/11 04:34:18 lwall |
16 | * patch2: CX/UX needed to set the key each time in associative iterators |
17 | * |
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18 | * Revision 3.0 89/10/18 15:18:32 lwall |
19 | * 3.0 baseline |
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20 | * |
21 | */ |
22 | |
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23 | #include "EXTERN.h" |
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24 | #include "perl.h" |
25 | |
26 | STR * |
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27 | hfetch(tb,key,klen,lval) |
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28 | register HASH *tb; |
29 | char *key; |
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30 | int klen; |
31 | int lval; |
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32 | { |
33 | register char *s; |
34 | register int i; |
35 | register int hash; |
36 | register HENT *entry; |
a687059c |
37 | register int maxi; |
38 | STR *str; |
39 | #ifdef SOME_DBM |
40 | datum dkey,dcontent; |
41 | #endif |
8d063cd8 |
42 | |
43 | if (!tb) |
44 | return Nullstr; |
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45 | |
46 | /* The hash function we use on symbols has to be equal to the first |
47 | * character when taken modulo 128, so that str_reset() can be implemented |
48 | * efficiently. We throw in the second character and the last character |
49 | * (times 128) so that long chains of identifiers starting with the |
50 | * same letter don't have to be strEQ'ed within hfetch(), since it |
51 | * compares hash values before trying strEQ(). |
52 | */ |
53 | if (!tb->tbl_coeffsize) |
54 | hash = *key + 128 * key[1] + 128 * key[klen-1]; /* assuming klen > 0 */ |
55 | else { /* use normal coefficients */ |
56 | if (klen < tb->tbl_coeffsize) |
57 | maxi = klen; |
58 | else |
59 | maxi = tb->tbl_coeffsize; |
60 | for (s=key, i=0, hash = 0; |
61 | i < maxi; |
62 | s++, i++, hash *= 5) { |
63 | hash += *s * coeff[i]; |
64 | } |
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65 | } |
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66 | |
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67 | entry = tb->tbl_array[hash & tb->tbl_max]; |
68 | for (; entry; entry = entry->hent_next) { |
69 | if (entry->hent_hash != hash) /* strings can't be equal */ |
70 | continue; |
a687059c |
71 | if (entry->hent_klen != klen) |
72 | continue; |
73 | if (bcmp(entry->hent_key,key,klen)) /* is this it? */ |
8d063cd8 |
74 | continue; |
75 | return entry->hent_val; |
76 | } |
a687059c |
77 | #ifdef SOME_DBM |
78 | if (tb->tbl_dbm) { |
79 | dkey.dptr = key; |
80 | dkey.dsize = klen; |
81 | dcontent = dbm_fetch(tb->tbl_dbm,dkey); |
82 | if (dcontent.dptr) { /* found one */ |
83 | str = Str_new(60,dcontent.dsize); |
84 | str_nset(str,dcontent.dptr,dcontent.dsize); |
85 | hstore(tb,key,klen,str,hash); /* cache it */ |
86 | return str; |
87 | } |
88 | } |
89 | #endif |
90 | if (lval) { /* gonna assign to this, so it better be there */ |
91 | str = Str_new(61,0); |
92 | hstore(tb,key,klen,str,hash); |
93 | return str; |
94 | } |
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95 | return Nullstr; |
96 | } |
97 | |
98 | bool |
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99 | hstore(tb,key,klen,val,hash) |
8d063cd8 |
100 | register HASH *tb; |
101 | char *key; |
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102 | int klen; |
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103 | STR *val; |
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104 | register int hash; |
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105 | { |
106 | register char *s; |
107 | register int i; |
8d063cd8 |
108 | register HENT *entry; |
109 | register HENT **oentry; |
a687059c |
110 | register int maxi; |
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111 | |
112 | if (!tb) |
113 | return FALSE; |
a687059c |
114 | |
115 | if (hash) |
116 | ; |
117 | else if (!tb->tbl_coeffsize) |
118 | hash = *key + 128 * key[1] + 128 * key[klen-1]; |
119 | else { /* use normal coefficients */ |
120 | if (klen < tb->tbl_coeffsize) |
121 | maxi = klen; |
122 | else |
123 | maxi = tb->tbl_coeffsize; |
124 | for (s=key, i=0, hash = 0; |
125 | i < maxi; |
126 | s++, i++, hash *= 5) { |
127 | hash += *s * coeff[i]; |
128 | } |
8d063cd8 |
129 | } |
130 | |
131 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
132 | i = 1; |
133 | |
134 | for (entry = *oentry; entry; i=0, entry = entry->hent_next) { |
135 | if (entry->hent_hash != hash) /* strings can't be equal */ |
136 | continue; |
a687059c |
137 | if (entry->hent_klen != klen) |
138 | continue; |
139 | if (bcmp(entry->hent_key,key,klen)) /* is this it? */ |
8d063cd8 |
140 | continue; |
a687059c |
141 | Safefree(entry->hent_val); |
8d063cd8 |
142 | entry->hent_val = val; |
143 | return TRUE; |
144 | } |
a687059c |
145 | New(501,entry, 1, HENT); |
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146 | |
a687059c |
147 | entry->hent_klen = klen; |
148 | entry->hent_key = nsavestr(key,klen); |
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149 | entry->hent_val = val; |
150 | entry->hent_hash = hash; |
151 | entry->hent_next = *oentry; |
152 | *oentry = entry; |
153 | |
a687059c |
154 | /* hdbmstore not necessary here because it's called from stabset() */ |
155 | |
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156 | if (i) { /* initial entry? */ |
157 | tb->tbl_fill++; |
a687059c |
158 | #ifdef SOME_DBM |
159 | if (tb->tbl_dbm && tb->tbl_max >= DBM_CACHE_MAX) |
160 | return FALSE; |
161 | #endif |
162 | if (tb->tbl_fill > tb->tbl_dosplit) |
8d063cd8 |
163 | hsplit(tb); |
164 | } |
a687059c |
165 | #ifdef SOME_DBM |
166 | else if (tb->tbl_dbm) { /* is this just a cache for dbm file? */ |
b1248f16 |
167 | void hentdelayfree(); |
168 | |
a687059c |
169 | entry = tb->tbl_array[hash & tb->tbl_max]; |
170 | oentry = &entry->hent_next; |
171 | entry = *oentry; |
172 | while (entry) { /* trim chain down to 1 entry */ |
173 | *oentry = entry->hent_next; |
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174 | hentdelayfree(entry); /* no doubt they'll want this next. */ |
a687059c |
175 | entry = *oentry; |
176 | } |
177 | } |
178 | #endif |
8d063cd8 |
179 | |
180 | return FALSE; |
181 | } |
182 | |
378cc40b |
183 | STR * |
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184 | hdelete(tb,key,klen) |
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185 | register HASH *tb; |
186 | char *key; |
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187 | int klen; |
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188 | { |
189 | register char *s; |
190 | register int i; |
191 | register int hash; |
192 | register HENT *entry; |
193 | register HENT **oentry; |
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194 | STR *str; |
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195 | int maxi; |
196 | #ifdef SOME_DBM |
197 | datum dkey; |
198 | #endif |
8d063cd8 |
199 | |
200 | if (!tb) |
378cc40b |
201 | return Nullstr; |
a687059c |
202 | if (!tb->tbl_coeffsize) |
203 | hash = *key + 128 * key[1] + 128 * key[klen-1]; |
204 | else { /* use normal coefficients */ |
205 | if (klen < tb->tbl_coeffsize) |
206 | maxi = klen; |
207 | else |
208 | maxi = tb->tbl_coeffsize; |
209 | for (s=key, i=0, hash = 0; |
210 | i < maxi; |
211 | s++, i++, hash *= 5) { |
212 | hash += *s * coeff[i]; |
213 | } |
8d063cd8 |
214 | } |
215 | |
216 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
217 | entry = *oentry; |
218 | i = 1; |
378cc40b |
219 | for (; entry; i=0, oentry = &entry->hent_next, entry = *oentry) { |
8d063cd8 |
220 | if (entry->hent_hash != hash) /* strings can't be equal */ |
221 | continue; |
a687059c |
222 | if (entry->hent_klen != klen) |
223 | continue; |
224 | if (bcmp(entry->hent_key,key,klen)) /* is this it? */ |
8d063cd8 |
225 | continue; |
8d063cd8 |
226 | *oentry = entry->hent_next; |
378cc40b |
227 | str = str_static(entry->hent_val); |
228 | hentfree(entry); |
8d063cd8 |
229 | if (i) |
230 | tb->tbl_fill--; |
a687059c |
231 | #ifdef SOME_DBM |
232 | do_dbm_delete: |
233 | if (tb->tbl_dbm) { |
234 | dkey.dptr = key; |
235 | dkey.dsize = klen; |
236 | dbm_delete(tb->tbl_dbm,dkey); |
237 | } |
238 | #endif |
378cc40b |
239 | return str; |
8d063cd8 |
240 | } |
a687059c |
241 | #ifdef SOME_DBM |
242 | str = Nullstr; |
243 | goto do_dbm_delete; |
244 | #else |
378cc40b |
245 | return Nullstr; |
a687059c |
246 | #endif |
8d063cd8 |
247 | } |
8d063cd8 |
248 | |
249 | hsplit(tb) |
250 | HASH *tb; |
251 | { |
252 | int oldsize = tb->tbl_max + 1; |
253 | register int newsize = oldsize * 2; |
254 | register int i; |
255 | register HENT **a; |
256 | register HENT **b; |
257 | register HENT *entry; |
258 | register HENT **oentry; |
259 | |
a687059c |
260 | a = tb->tbl_array; |
261 | Renew(a, newsize, HENT*); |
262 | Zero(&a[oldsize], oldsize, HENT*); /* zero 2nd half*/ |
8d063cd8 |
263 | tb->tbl_max = --newsize; |
a687059c |
264 | tb->tbl_dosplit = tb->tbl_max * FILLPCT / 100; |
8d063cd8 |
265 | tb->tbl_array = a; |
266 | |
267 | for (i=0; i<oldsize; i++,a++) { |
268 | if (!*a) /* non-existent */ |
269 | continue; |
270 | b = a+oldsize; |
271 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
272 | if ((entry->hent_hash & newsize) != i) { |
273 | *oentry = entry->hent_next; |
274 | entry->hent_next = *b; |
275 | if (!*b) |
276 | tb->tbl_fill++; |
277 | *b = entry; |
278 | continue; |
279 | } |
280 | else |
281 | oentry = &entry->hent_next; |
282 | } |
283 | if (!*a) /* everything moved */ |
284 | tb->tbl_fill--; |
285 | } |
286 | } |
287 | |
288 | HASH * |
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289 | hnew(lookat) |
290 | unsigned int lookat; |
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291 | { |
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292 | register HASH *tb; |
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293 | |
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294 | Newz(502,tb, 1, HASH); |
295 | if (lookat) { |
296 | tb->tbl_coeffsize = lookat; |
297 | tb->tbl_max = 7; /* it's a normal associative array */ |
298 | tb->tbl_dosplit = tb->tbl_max * FILLPCT / 100; |
299 | } |
300 | else { |
301 | tb->tbl_max = 127; /* it's a symbol table */ |
302 | tb->tbl_dosplit = 128; /* so never split */ |
303 | } |
304 | Newz(503,tb->tbl_array, tb->tbl_max + 1, HENT*); |
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305 | tb->tbl_fill = 0; |
a687059c |
306 | #ifdef SOME_DBM |
307 | tb->tbl_dbm = 0; |
308 | #endif |
309 | (void)hiterinit(tb); /* so each() will start off right */ |
8d063cd8 |
310 | return tb; |
311 | } |
312 | |
378cc40b |
313 | void |
314 | hentfree(hent) |
315 | register HENT *hent; |
316 | { |
317 | if (!hent) |
318 | return; |
319 | str_free(hent->hent_val); |
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320 | Safefree(hent->hent_key); |
321 | Safefree(hent); |
378cc40b |
322 | } |
323 | |
324 | void |
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325 | hentdelayfree(hent) |
326 | register HENT *hent; |
327 | { |
328 | if (!hent) |
329 | return; |
330 | str_2static(hent->hent_val); /* free between statements */ |
331 | Safefree(hent->hent_key); |
332 | Safefree(hent); |
333 | } |
334 | |
335 | void |
378cc40b |
336 | hclear(tb) |
337 | register HASH *tb; |
338 | { |
339 | register HENT *hent; |
340 | register HENT *ohent = Null(HENT*); |
341 | |
342 | if (!tb) |
343 | return; |
a687059c |
344 | (void)hiterinit(tb); |
378cc40b |
345 | while (hent = hiternext(tb)) { /* concise but not very efficient */ |
346 | hentfree(ohent); |
347 | ohent = hent; |
348 | } |
349 | hentfree(ohent); |
350 | tb->tbl_fill = 0; |
a687059c |
351 | #ifndef lint |
352 | (void)bzero((char*)tb->tbl_array, (tb->tbl_max + 1) * sizeof(HENT*)); |
353 | #endif |
378cc40b |
354 | } |
355 | |
378cc40b |
356 | void |
357 | hfree(tb) |
a687059c |
358 | register HASH *tb; |
378cc40b |
359 | { |
a687059c |
360 | register HENT *hent; |
361 | register HENT *ohent = Null(HENT*); |
362 | |
378cc40b |
363 | if (!tb) |
a687059c |
364 | return; |
365 | (void)hiterinit(tb); |
378cc40b |
366 | while (hent = hiternext(tb)) { |
367 | hentfree(ohent); |
368 | ohent = hent; |
369 | } |
370 | hentfree(ohent); |
a687059c |
371 | Safefree(tb->tbl_array); |
372 | Safefree(tb); |
378cc40b |
373 | } |
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374 | |
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375 | int |
8d063cd8 |
376 | hiterinit(tb) |
377 | register HASH *tb; |
378 | { |
379 | tb->tbl_riter = -1; |
380 | tb->tbl_eiter = Null(HENT*); |
381 | return tb->tbl_fill; |
382 | } |
383 | |
384 | HENT * |
385 | hiternext(tb) |
386 | register HASH *tb; |
387 | { |
388 | register HENT *entry; |
a687059c |
389 | #ifdef SOME_DBM |
390 | datum key; |
391 | #endif |
8d063cd8 |
392 | |
393 | entry = tb->tbl_eiter; |
a687059c |
394 | #ifdef SOME_DBM |
395 | if (tb->tbl_dbm) { |
396 | if (entry) { |
397 | #ifdef NDBM |
398 | #ifdef _CX_UX |
bf38876a |
399 | key.dptr = entry->hent_key; |
400 | key.dsize = entry->hent_klen; |
a687059c |
401 | key = dbm_nextkey(tb->tbl_dbm, key); |
402 | #else |
403 | key = dbm_nextkey(tb->tbl_dbm); |
404 | #endif /* _CX_UX */ |
405 | #else |
406 | key.dptr = entry->hent_key; |
407 | key.dsize = entry->hent_klen; |
408 | key = nextkey(key); |
409 | #endif |
410 | } |
411 | else { |
412 | Newz(504,entry, 1, HENT); |
413 | tb->tbl_eiter = entry; |
414 | key = dbm_firstkey(tb->tbl_dbm); |
415 | } |
416 | entry->hent_key = key.dptr; |
417 | entry->hent_klen = key.dsize; |
418 | if (!key.dptr) { |
419 | if (entry->hent_val) |
420 | str_free(entry->hent_val); |
421 | Safefree(entry); |
422 | tb->tbl_eiter = Null(HENT*); |
423 | return Null(HENT*); |
424 | } |
425 | return entry; |
426 | } |
427 | #endif |
8d063cd8 |
428 | do { |
429 | if (entry) |
430 | entry = entry->hent_next; |
431 | if (!entry) { |
432 | tb->tbl_riter++; |
433 | if (tb->tbl_riter > tb->tbl_max) { |
434 | tb->tbl_riter = -1; |
435 | break; |
436 | } |
437 | entry = tb->tbl_array[tb->tbl_riter]; |
438 | } |
439 | } while (!entry); |
440 | |
441 | tb->tbl_eiter = entry; |
442 | return entry; |
443 | } |
444 | |
445 | char * |
a687059c |
446 | hiterkey(entry,retlen) |
8d063cd8 |
447 | register HENT *entry; |
a687059c |
448 | int *retlen; |
8d063cd8 |
449 | { |
a687059c |
450 | *retlen = entry->hent_klen; |
8d063cd8 |
451 | return entry->hent_key; |
452 | } |
453 | |
454 | STR * |
a687059c |
455 | hiterval(tb,entry) |
456 | register HASH *tb; |
8d063cd8 |
457 | register HENT *entry; |
458 | { |
a687059c |
459 | #ifdef SOME_DBM |
460 | datum key, content; |
461 | |
462 | if (tb->tbl_dbm) { |
463 | key.dptr = entry->hent_key; |
464 | key.dsize = entry->hent_klen; |
465 | content = dbm_fetch(tb->tbl_dbm,key); |
466 | if (!entry->hent_val) |
467 | entry->hent_val = Str_new(62,0); |
468 | str_nset(entry->hent_val,content.dptr,content.dsize); |
469 | } |
470 | #endif |
8d063cd8 |
471 | return entry->hent_val; |
472 | } |
a687059c |
473 | |
474 | #ifdef SOME_DBM |
475 | #if defined(FCNTL) && ! defined(O_CREAT) |
476 | #include <fcntl.h> |
477 | #endif |
478 | |
479 | #ifndef O_RDONLY |
480 | #define O_RDONLY 0 |
481 | #endif |
482 | #ifndef O_RDWR |
483 | #define O_RDWR 2 |
484 | #endif |
485 | #ifndef O_CREAT |
486 | #define O_CREAT 01000 |
487 | #endif |
488 | |
489 | #ifndef NDBM |
490 | static int dbmrefcnt = 0; |
491 | #endif |
492 | |
493 | bool |
494 | hdbmopen(tb,fname,mode) |
495 | register HASH *tb; |
496 | char *fname; |
497 | int mode; |
498 | { |
499 | if (!tb) |
500 | return FALSE; |
501 | #ifndef NDBM |
502 | if (tb->tbl_dbm) /* never really closed it */ |
503 | return TRUE; |
504 | #endif |
505 | if (tb->tbl_dbm) |
506 | hdbmclose(tb); |
507 | hclear(tb); |
508 | #ifdef NDBM |
509 | tb->tbl_dbm = dbm_open(fname, O_RDWR|O_CREAT, mode); |
510 | if (!tb->tbl_dbm) /* oops, just try reading it */ |
511 | tb->tbl_dbm = dbm_open(fname, O_RDONLY, mode); |
512 | #else |
513 | if (dbmrefcnt++) |
514 | fatal("Old dbm can only open one database"); |
515 | sprintf(buf,"%s.dir",fname); |
516 | if (stat(buf, &statbuf) < 0) { |
517 | if (close(creat(buf,mode)) < 0) |
518 | return FALSE; |
519 | sprintf(buf,"%s.pag",fname); |
520 | if (close(creat(buf,mode)) < 0) |
521 | return FALSE; |
522 | } |
523 | tb->tbl_dbm = dbminit(fname) >= 0; |
524 | #endif |
525 | return tb->tbl_dbm != 0; |
526 | } |
527 | |
528 | void |
529 | hdbmclose(tb) |
530 | register HASH *tb; |
531 | { |
532 | if (tb && tb->tbl_dbm) { |
533 | #ifdef NDBM |
534 | dbm_close(tb->tbl_dbm); |
535 | tb->tbl_dbm = 0; |
536 | #else |
537 | /* dbmrefcnt--; */ /* doesn't work, rats */ |
538 | #endif |
539 | } |
540 | else if (dowarn) |
541 | warn("Close on unopened dbm file"); |
542 | } |
543 | |
544 | bool |
545 | hdbmstore(tb,key,klen,str) |
546 | register HASH *tb; |
547 | char *key; |
548 | int klen; |
549 | register STR *str; |
550 | { |
551 | datum dkey, dcontent; |
552 | int error; |
553 | |
554 | if (!tb || !tb->tbl_dbm) |
555 | return FALSE; |
556 | dkey.dptr = key; |
557 | dkey.dsize = klen; |
558 | dcontent.dptr = str_get(str); |
559 | dcontent.dsize = str->str_cur; |
560 | error = dbm_store(tb->tbl_dbm, dkey, dcontent, DBM_REPLACE); |
561 | if (error) { |
562 | if (errno == EPERM) |
563 | fatal("No write permission to dbm file"); |
564 | warn("dbm store returned %d, errno %d, key \"%s\"",error,errno,key); |
565 | #ifdef NDBM |
566 | dbm_clearerr(tb->tbl_dbm); |
567 | #endif |
568 | } |
569 | return !error; |
570 | } |
571 | #endif /* SOME_DBM */ |