70322ae3 |
1 | /* |
2 | * trie.c: implementation of trie.h. |
3 | */ |
4 | |
353bc75d |
5 | #include "agedu.h" |
995db599 |
6 | #include "alloc.h" |
70322ae3 |
7 | #include "trie.h" |
8 | |
9 | #define alignof(typ) ( offsetof(struct { char c; typ t; }, t) ) |
10 | |
11 | /* |
12 | * Compare functions for pathnames. Returns the relative order of |
13 | * the names, like strcmp; also passes back the offset of the |
14 | * first differing character if desired. |
15 | */ |
16 | static int trieccmp(unsigned char a, unsigned char b) |
17 | { |
2f23825b |
18 | int ia = (a == '\0' ? '\0' : a == pathsep ? '\1' : a+1); |
19 | int ib = (b == '\0' ? '\0' : b == pathsep ? '\1' : b+1); |
20 | return ia - ib; |
70322ae3 |
21 | } |
22 | |
23 | static int triencmp(const char *a, size_t alen, |
24 | const char *b, size_t blen, int *offset) |
25 | { |
26 | int off = 0; |
27 | while (off < alen && off < blen && a[off] == b[off]) |
28 | off++; |
29 | if (offset) |
30 | *offset = off; |
31 | if (off == alen || off == blen) return (off == blen) - (off == alen); |
32 | return trieccmp(a[off], b[off]); |
33 | } |
34 | |
35 | static int triecmp(const char *a, const char *b, int *offset) |
36 | { |
37 | return triencmp(a, strlen(a), b, strlen(b), offset); |
38 | } |
39 | |
40 | /* ---------------------------------------------------------------------- |
41 | * Trie node structures. |
42 | * |
43 | * The trie format stored in the file consists of three distinct |
44 | * node types, each with a distinguishing type field at the start. |
45 | * |
46 | * TRIE_LEAF is a leaf node; it contains an actual trie_file |
47 | * structure, and indicates that when you're searching down the |
48 | * trie with a string, you should now expect to encounter |
49 | * end-of-string. |
50 | * |
51 | * TRIE_SWITCH indicates that the set of strings in the trie |
52 | * include strings with more than one distinct character after the |
53 | * prefix leading up to this point. Hence, it stores multiple |
54 | * subnode pointers and a different single character for each one. |
55 | * |
56 | * TRIE_STRING indicates that at this point everything in the trie |
57 | * has the same next few characters; it stores a single mandatory |
58 | * string fragment and exactly one subnode pointer. |
59 | */ |
60 | enum { |
61 | TRIE_LEAF = 0x7fffe000, |
62 | TRIE_SWITCH, |
63 | TRIE_STRING |
64 | }; |
65 | |
66 | struct trie_common { |
67 | int type; |
68 | }; |
69 | |
70 | struct trie_switchentry { |
71 | off_t subnode; |
72 | int subcount; |
73 | }; |
74 | |
75 | struct trie_leaf { |
76 | struct trie_common c; |
77 | struct trie_file file; |
78 | }; |
79 | |
80 | struct trie_switch { |
81 | struct trie_common c; |
82 | /* |
83 | * sw[0] to sw[len-1] give the subnode pointers and element |
84 | * counts. At &sw[len] is stored len single bytes which are |
85 | * the characters corresponding to each subnode. |
86 | */ |
87 | int len; |
88 | struct trie_switchentry sw[]; |
89 | }; |
90 | |
91 | struct trie_string { |
92 | struct trie_common c; |
93 | int stringlen; |
94 | off_t subnode; |
95 | char string[]; |
96 | }; |
97 | |
98 | struct trie_header { |
99 | unsigned long magic; |
100 | off_t root, indexroot; |
101 | int count; |
102 | size_t maxpathlen; |
269fa2d1 |
103 | int pathsep; |
70322ae3 |
104 | }; |
105 | |
106 | /* Union only used for computing alignment */ |
107 | union trie_node { |
108 | struct trie_leaf leaf; |
109 | struct { /* fake trie_switch with indeterminate array length filled in */ |
110 | struct trie_common c; |
111 | int len; |
112 | struct trie_switchentry sw[1]; |
113 | } sw; |
114 | struct { /* fake trie_string with indeterminate array length filled in */ |
115 | struct trie_common c; |
116 | int stringlen; |
117 | off_t subnode; |
118 | char string[1]; |
119 | } str; |
120 | }; |
121 | #define TRIE_MAGIC 0x75646761UL |
122 | #define TRIE_ALIGN alignof(union trie_node) |
123 | |
124 | /* ---------------------------------------------------------------------- |
125 | * Trie-building functions. |
126 | */ |
127 | |
128 | struct tbswitch { |
129 | int len; |
130 | char c[256]; |
131 | off_t off[256]; |
132 | int count[256]; |
133 | }; |
134 | |
135 | struct triebuild { |
136 | int fd; |
137 | off_t offset; |
138 | char *lastpath; |
139 | int lastlen, lastsize; |
140 | off_t lastoff; |
141 | struct tbswitch *switches; |
142 | int switchsize; |
143 | size_t maxpathlen; |
144 | }; |
145 | |
146 | static void tb_seek(triebuild *tb, off_t off) |
147 | { |
148 | tb->offset = off; |
149 | if (lseek(tb->fd, off, SEEK_SET) < 0) { |
bf53e756 |
150 | fprintf(stderr, PNAME ": lseek: %s\n", strerror(errno)); |
70322ae3 |
151 | exit(1); |
152 | } |
153 | } |
154 | |
155 | static void tb_write(triebuild *tb, const void *buf, size_t len) |
156 | { |
157 | tb->offset += len; |
158 | while (len > 0) { |
159 | int ret = write(tb->fd, buf, len); |
160 | if (ret < 0) { |
bf53e756 |
161 | fprintf(stderr, PNAME ": write: %s\n", strerror(errno)); |
70322ae3 |
162 | exit(1); |
163 | } |
164 | len -= ret; |
165 | buf = (const void *)((const char *)buf + ret); |
166 | } |
167 | } |
168 | |
169 | static char trie_align_zeroes[TRIE_ALIGN]; |
170 | |
171 | static void tb_align(triebuild *tb) |
172 | { |
173 | int off = (TRIE_ALIGN - ((tb)->offset % TRIE_ALIGN)) % TRIE_ALIGN; |
174 | tb_write(tb, trie_align_zeroes, off); |
175 | } |
176 | |
177 | triebuild *triebuild_new(int fd) |
178 | { |
179 | triebuild *tb = snew(triebuild); |
180 | struct trie_header th; |
181 | |
182 | tb->fd = fd; |
183 | tb->lastpath = NULL; |
184 | tb->lastlen = tb->lastsize = 0; |
185 | tb->lastoff = 0; |
186 | tb->switches = NULL; |
187 | tb->switchsize = 0; |
188 | tb->maxpathlen = 0; |
189 | |
190 | th.magic = TRIE_MAGIC; |
191 | th.root = th.count = 0; |
192 | th.indexroot = 0; |
193 | th.maxpathlen = 0; |
269fa2d1 |
194 | th.pathsep = (unsigned char)pathsep; |
70322ae3 |
195 | |
196 | tb_seek(tb, 0); |
197 | tb_write(tb, &th, sizeof(th)); |
198 | |
199 | return tb; |
200 | } |
201 | |
202 | static off_t triebuild_unwind(triebuild *tb, int targetdepth, int *outcount) |
203 | { |
204 | off_t offset; |
205 | int count, depth; |
206 | |
207 | if (tb->lastoff == 0) { |
208 | *outcount = 0; |
209 | return 0; |
210 | } |
211 | |
212 | offset = tb->lastoff; |
213 | count = 1; |
214 | depth = tb->lastlen + 1; |
215 | |
216 | assert(depth >= targetdepth); |
217 | |
218 | while (depth > targetdepth) { |
219 | int odepth = depth; |
220 | while (depth > targetdepth && |
cf39b588 |
221 | (depth-1 > tb->switchsize || !tb->switches || |
222 | tb->switches[depth-1].len == 0)) |
70322ae3 |
223 | depth--; |
224 | if (odepth > depth) { |
225 | /* |
226 | * Write out a string node. |
227 | */ |
228 | size_t nodesize = sizeof(struct trie_string) + odepth - depth; |
229 | struct trie_string *st = (struct trie_string *)smalloc(nodesize); |
230 | st->c.type = TRIE_STRING; |
231 | st->stringlen = odepth - depth; |
232 | st->subnode = offset; |
233 | memcpy(st->string, tb->lastpath + depth, odepth - depth); |
234 | tb_align(tb); |
235 | offset = tb->offset; |
236 | tb_write(tb, st, nodesize); |
237 | sfree(st); |
238 | } |
239 | |
240 | assert(depth >= targetdepth); |
241 | if (depth <= targetdepth) |
242 | break; |
243 | |
244 | /* |
245 | * Now we expect to be sitting just below a switch node. |
246 | * Add our final entry to it and write it out. |
247 | */ |
248 | depth--; |
249 | { |
250 | struct trie_switch *sw; |
251 | char *chars; |
252 | size_t nodesize; |
253 | int swlen = tb->switches[depth].len; |
254 | int i; |
255 | |
256 | assert(swlen > 0); |
257 | |
258 | tb->switches[depth].c[swlen] = tb->lastpath[depth]; |
259 | tb->switches[depth].off[swlen] = offset; |
260 | tb->switches[depth].count[swlen] = count; |
261 | swlen++; |
262 | |
263 | nodesize = sizeof(struct trie_switch) + |
264 | swlen * sizeof(struct trie_switchentry) + swlen; |
265 | sw = (struct trie_switch *)smalloc(nodesize); |
266 | chars = (char *)&sw->sw[swlen]; |
267 | |
268 | sw->c.type = TRIE_SWITCH; |
269 | sw->len = swlen; |
270 | count = 0; |
271 | for (i = 0; i < swlen; i++) { |
272 | sw->sw[i].subnode = tb->switches[depth].off[i]; |
273 | sw->sw[i].subcount = tb->switches[depth].count[i]; |
274 | chars[i] = tb->switches[depth].c[i]; |
275 | |
276 | count += tb->switches[depth].count[i]; |
277 | } |
278 | |
279 | tb_align(tb); |
280 | offset = tb->offset; |
281 | tb_write(tb, sw, nodesize); |
282 | sfree(sw); |
283 | |
284 | tb->switches[depth].len = 0; /* clear this node */ |
285 | } |
286 | } |
287 | |
288 | *outcount = count; |
289 | return offset; |
290 | } |
291 | |
292 | void triebuild_add(triebuild *tb, const char *pathname, |
293 | const struct trie_file *file) |
294 | { |
295 | int pathlen = strlen(pathname); |
296 | int depth; |
297 | |
298 | if (tb->maxpathlen < pathlen+1) |
299 | tb->maxpathlen = pathlen+1; |
300 | |
301 | if (tb->lastpath) { |
302 | off_t offset; |
303 | int count; |
304 | |
305 | /* |
306 | * Find the first differing character between this pathname |
307 | * and the previous one. |
308 | */ |
309 | int ret = triecmp(tb->lastpath, pathname, &depth); |
310 | assert(ret < 0); |
311 | |
312 | /* |
313 | * Finalise all nodes above this depth. |
314 | */ |
315 | offset = triebuild_unwind(tb, depth+1, &count); |
316 | |
317 | /* |
318 | * Add the final node we just acquired to the switch node |
319 | * at our chosen depth, creating it if it isn't already |
320 | * there. |
321 | */ |
322 | if (tb->switchsize <= depth) { |
323 | int oldsize = tb->switchsize; |
324 | tb->switchsize = depth * 3 / 2 + 64; |
325 | tb->switches = sresize(tb->switches, tb->switchsize, |
326 | struct tbswitch); |
327 | while (oldsize < tb->switchsize) |
328 | tb->switches[oldsize++].len = 0; |
329 | } |
330 | |
331 | tb->switches[depth].c[tb->switches[depth].len] = tb->lastpath[depth]; |
332 | tb->switches[depth].off[tb->switches[depth].len] = offset; |
333 | tb->switches[depth].count[tb->switches[depth].len] = count; |
334 | tb->switches[depth].len++; |
335 | } |
336 | |
337 | /* |
338 | * Write out a leaf node for the new file, and remember its |
339 | * file offset. |
340 | */ |
341 | { |
342 | struct trie_leaf leaf; |
343 | |
344 | leaf.c.type = TRIE_LEAF; |
345 | leaf.file = *file; /* structure copy */ |
346 | |
347 | tb_align(tb); |
348 | tb->lastoff = tb->offset; |
349 | tb_write(tb, &leaf, sizeof(leaf)); |
350 | } |
351 | |
352 | /* |
353 | * Store this pathname for comparison with the next one. |
354 | */ |
355 | if (tb->lastsize < pathlen+1) { |
356 | tb->lastsize = pathlen * 3 / 2 + 64; |
357 | tb->lastpath = sresize(tb->lastpath, tb->lastsize, char); |
358 | } |
359 | strcpy(tb->lastpath, pathname); |
360 | tb->lastlen = pathlen; |
361 | } |
362 | |
363 | int triebuild_finish(triebuild *tb) |
364 | { |
365 | struct trie_header th; |
366 | |
367 | th.magic = TRIE_MAGIC; |
368 | th.root = triebuild_unwind(tb, 0, &th.count); |
369 | th.indexroot = 0; |
370 | th.maxpathlen = tb->maxpathlen; |
269fa2d1 |
371 | th.pathsep = (unsigned char)pathsep; |
70322ae3 |
372 | |
373 | tb_seek(tb, 0); |
374 | tb_write(tb, &th, sizeof(th)); |
375 | |
376 | return th.count; |
377 | } |
378 | |
379 | void triebuild_free(triebuild *tb) |
380 | { |
381 | sfree(tb->switches); |
382 | sfree(tb->lastpath); |
383 | sfree(tb); |
384 | } |
385 | |
386 | /* ---------------------------------------------------------------------- |
05b0f827 |
387 | * Memory-mapped trie modification. |
388 | */ |
389 | |
390 | #define MNODE(t, off, type) \ |
391 | ((struct type *)((char *)(t) + (off))) |
392 | |
393 | static unsigned long long fake_atime_recurse(void *t, struct trie_common *node, |
394 | int last_seen_pathsep) |
395 | { |
396 | while (node->type == TRIE_STRING) { |
397 | struct trie_string *st = (struct trie_string *)node; |
398 | last_seen_pathsep = (st->string[st->stringlen-1] == pathsep); |
399 | node = MNODE(t, st->subnode, trie_common); |
400 | } |
401 | |
402 | if (node->type == TRIE_LEAF) { |
403 | struct trie_leaf *leaf = (struct trie_leaf *)node; |
404 | return leaf->file.atime; |
405 | } else if (assert(node->type == TRIE_SWITCH), 1) { |
406 | struct trie_switch *sw = (struct trie_switch *)node; |
407 | const char *chars = (const char *)&sw->sw[sw->len]; |
408 | unsigned long long max = 0, subdir, ret; |
409 | int i; |
410 | int slashindex = -1, bareindex = -1; |
411 | |
412 | /* |
413 | * First, process all the children of this node whose |
414 | * switch characters are not \0 or pathsep. We do this in |
415 | * reverse order so as to maintain best cache locality |
416 | * (tracking generally backwards through the file), though |
417 | * it doesn't matter semantically. |
418 | * |
419 | * For each of these children, we're just recursing into |
420 | * it to do any fixups required below it, and amalgamating |
421 | * the max atimes we get back. |
422 | */ |
423 | for (i = sw->len; i-- > 0 ;) { |
424 | if (chars[i] == '\0') { |
425 | bareindex = i; |
426 | } else if (chars[i] == pathsep) { |
427 | slashindex = i; |
428 | } else { |
429 | ret = fake_atime_recurse(t, MNODE(t, sw->sw[i].subnode, |
430 | trie_common), 0); |
431 | if (max < ret) |
432 | max = ret; |
433 | } |
434 | } |
435 | |
436 | /* |
437 | * Now we have at most two child nodes left to deal with: |
438 | * one with a slash (or general pathsep) and one with \0. |
439 | * |
440 | * If there's a slash node and a bare node, then the slash |
441 | * node contains precisely everything inside the directory |
442 | * described by the bare node; so we must retrieve the max |
443 | * atime for the slash node and use it to fix up the bare |
444 | * node. |
445 | * |
446 | * If there's only a bare node but the pathname leading up |
447 | * to this point ends in a slash, then _all_ of the child |
448 | * nodes of this node contain stuff inside the directory |
449 | * described by the bare node; so we use the whole of the |
450 | * maximum value we've computed so far to update the bare |
451 | * node. |
452 | */ |
453 | if (slashindex >= 0) { |
454 | ret = fake_atime_recurse(t, MNODE(t, sw->sw[slashindex].subnode, |
455 | trie_common), 1); |
456 | if (max < ret) |
457 | max = ret; |
458 | |
459 | subdir = ret; |
460 | } else if (last_seen_pathsep) { |
461 | subdir = max; |
462 | } else { |
463 | /* Don't update the bare subnode at all. */ |
464 | subdir = 0; |
465 | } |
466 | |
467 | if (bareindex >= 0) { |
468 | struct trie_leaf *leaf; |
469 | |
470 | leaf = MNODE(t, sw->sw[bareindex].subnode, trie_leaf); |
471 | |
472 | if (leaf && leaf->c.type == TRIE_LEAF) { |
473 | if (leaf->file.atime < subdir) |
474 | leaf->file.atime = subdir; |
475 | ret = leaf->file.atime; |
476 | } else { |
477 | /* Shouldn't really happen, but be cautious anyway */ |
478 | ret = fake_atime_recurse(t, &leaf->c, 0); |
479 | } |
480 | |
481 | if (max < ret) |
482 | max = ret; |
483 | } |
484 | |
485 | return max; |
486 | } |
487 | } |
488 | |
489 | void trie_fake_dir_atimes(void *t) |
490 | { |
491 | struct trie_header *hdr = MNODE(t, 0, trie_header); |
492 | struct trie_common *node = MNODE(t, hdr->root, trie_common); |
493 | |
494 | fake_atime_recurse(t, node, 1); |
495 | } |
496 | |
497 | /* ---------------------------------------------------------------------- |
70322ae3 |
498 | * Querying functions. |
499 | */ |
500 | |
501 | #define NODE(t, off, type) \ |
502 | ((const struct type *)((const char *)(t) + (off))) |
503 | |
504 | size_t trie_maxpathlen(const void *t) |
505 | { |
506 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
507 | return hdr->maxpathlen; |
508 | } |
509 | |
510 | unsigned long trie_before(const void *t, const char *pathname) |
511 | { |
512 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
513 | int ret = 0, lastcount = hdr->count; |
514 | int len = 1 + strlen(pathname), depth = 0; |
515 | off_t off = hdr->root; |
516 | |
517 | while (1) { |
518 | const struct trie_common *node = NODE(t, off, trie_common); |
519 | if (node->type == TRIE_LEAF) { |
520 | if (depth < len) |
521 | ret += lastcount; /* _shouldn't_ happen, but in principle */ |
522 | return ret; |
523 | } else if (node->type == TRIE_STRING) { |
524 | const struct trie_string *st = NODE(t, off, trie_string); |
525 | |
526 | int offset; |
527 | int cmp = triencmp(st->string, st->stringlen, |
528 | pathname + depth, len-depth, &offset); |
529 | |
530 | if (offset < st->stringlen) { |
531 | if (cmp < 0) |
532 | ret += lastcount; |
533 | return ret; |
534 | } |
535 | |
536 | depth += st->stringlen; |
537 | off = st->subnode; |
538 | } else if (node->type == TRIE_SWITCH) { |
539 | const struct trie_switch *sw = NODE(t, off, trie_switch); |
540 | const char *chars = (const char *)&sw->sw[sw->len]; |
541 | int i; |
542 | |
543 | for (i = 0; i < sw->len; i++) { |
544 | int c = chars[i]; |
545 | int cmp = trieccmp(pathname[depth], c); |
546 | if (cmp > 0) |
547 | ret += sw->sw[i].subcount; |
548 | else if (cmp < 0) |
549 | return ret; |
550 | else { |
551 | off = sw->sw[i].subnode; |
552 | lastcount = sw->sw[i].subcount; |
553 | depth++; |
554 | break; |
555 | } |
556 | } |
557 | if (i == sw->len) |
558 | return ret; |
559 | } |
560 | } |
561 | } |
562 | |
563 | void trie_getpath(const void *t, unsigned long n, char *buf) |
564 | { |
565 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
566 | int depth = 0; |
567 | off_t off = hdr->root; |
568 | |
569 | while (1) { |
570 | const struct trie_common *node = NODE(t, off, trie_common); |
571 | if (node->type == TRIE_LEAF) { |
572 | assert(depth > 0 && buf[depth-1] == '\0'); |
573 | return; |
574 | } else if (node->type == TRIE_STRING) { |
575 | const struct trie_string *st = NODE(t, off, trie_string); |
576 | |
577 | memcpy(buf + depth, st->string, st->stringlen); |
578 | depth += st->stringlen; |
579 | off = st->subnode; |
580 | } else if (node->type == TRIE_SWITCH) { |
581 | const struct trie_switch *sw = NODE(t, off, trie_switch); |
582 | const char *chars = (const char *)&sw->sw[sw->len]; |
583 | int i; |
584 | |
585 | for (i = 0; i < sw->len; i++) { |
586 | if (n < sw->sw[i].subcount) { |
587 | buf[depth++] = chars[i]; |
588 | off = sw->sw[i].subnode; |
589 | break; |
590 | } else |
591 | n -= sw->sw[i].subcount; |
592 | } |
593 | assert(i < sw->len); |
594 | } |
595 | } |
16139d21 |
596 | } |
597 | |
598 | const struct trie_file *trie_getfile(const void *t, unsigned long n) |
599 | { |
600 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
601 | off_t off = hdr->root; |
602 | |
603 | while (1) { |
604 | const struct trie_common *node = NODE(t, off, trie_common); |
605 | if (node->type == TRIE_LEAF) { |
606 | const struct trie_leaf *leaf = NODE(t, off, trie_leaf); |
607 | return &leaf->file; |
608 | } else if (node->type == TRIE_STRING) { |
609 | const struct trie_string *st = NODE(t, off, trie_string); |
610 | off = st->subnode; |
611 | } else if (node->type == TRIE_SWITCH) { |
612 | const struct trie_switch *sw = NODE(t, off, trie_switch); |
613 | int i; |
614 | |
615 | for (i = 0; i < sw->len; i++) { |
616 | if (n < sw->sw[i].subcount) { |
617 | off = sw->sw[i].subnode; |
618 | break; |
619 | } else |
620 | n -= sw->sw[i].subcount; |
621 | } |
622 | assert(i < sw->len); |
623 | } |
624 | } |
625 | } |
70322ae3 |
626 | |
627 | unsigned long trie_count(const void *t) |
628 | { |
629 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
630 | return hdr->count; |
631 | } |
632 | |
269fa2d1 |
633 | char trie_pathsep(const void *t) |
634 | { |
635 | const struct trie_header *hdr = NODE(t, 0, trie_header); |
636 | return (char)hdr->pathsep; |
637 | } |
638 | |
70322ae3 |
639 | struct triewalk_switch { |
640 | const struct trie_switch *sw; |
641 | int pos, depth, count; |
642 | }; |
643 | struct triewalk { |
644 | const void *t; |
645 | struct triewalk_switch *switches; |
646 | int nswitches, switchsize; |
647 | int count; |
648 | }; |
649 | triewalk *triewalk_new(const void *vt) |
650 | { |
651 | triewalk *tw = snew(triewalk); |
652 | |
653 | tw->t = (const char *)vt; |
654 | tw->switches = NULL; |
655 | tw->switchsize = 0; |
656 | tw->nswitches = -1; |
657 | tw->count = 0; |
658 | |
659 | return tw; |
660 | } |
522edd92 |
661 | |
662 | void triewalk_rebase(triewalk *tw, const void *t) |
663 | { |
664 | ptrdiff_t diff = ((const unsigned char *)t - (const unsigned char *)(tw->t)); |
665 | int i; |
666 | |
667 | tw->t = t; |
668 | |
669 | for (i = 0; i < tw->nswitches; i++) |
670 | tw->switches[i].sw = (const struct trie_switch *) |
671 | ((const unsigned char *)(tw->switches[i].sw) + diff); |
672 | } |
673 | |
70322ae3 |
674 | const struct trie_file *triewalk_next(triewalk *tw, char *buf) |
675 | { |
676 | off_t off; |
677 | int depth; |
678 | |
679 | if (tw->nswitches < 0) { |
680 | const struct trie_header *hdr = NODE(tw->t, 0, trie_header); |
681 | off = hdr->root; |
682 | depth = 0; |
683 | tw->nswitches = 0; |
684 | } else { |
685 | while (1) { |
686 | int swpos; |
687 | const struct trie_switch *sw; |
688 | const char *chars; |
689 | |
690 | if (tw->nswitches == 0) { |
691 | assert(tw->count == NODE(tw->t, 0, trie_header)->count); |
692 | return NULL; /* run out of trie */ |
693 | } |
694 | |
695 | swpos = tw->switches[tw->nswitches-1].pos; |
696 | sw = tw->switches[tw->nswitches-1].sw; |
697 | chars = (const char *)&sw->sw[sw->len]; |
698 | |
699 | if (swpos < sw->len) { |
700 | depth = tw->switches[tw->nswitches-1].depth; |
701 | off = sw->sw[swpos].subnode; |
702 | if (buf) |
703 | buf[depth++] = chars[swpos]; |
704 | assert(tw->count == tw->switches[tw->nswitches-1].count); |
705 | tw->switches[tw->nswitches-1].count += sw->sw[swpos].subcount; |
706 | tw->switches[tw->nswitches-1].pos++; |
707 | break; |
708 | } |
709 | |
710 | tw->nswitches--; |
711 | } |
712 | } |
713 | |
714 | while (1) { |
715 | const struct trie_common *node = NODE(tw->t, off, trie_common); |
716 | if (node->type == TRIE_LEAF) { |
717 | const struct trie_leaf *lf = NODE(tw->t, off, trie_leaf); |
718 | if (buf) |
719 | assert(depth > 0 && buf[depth-1] == '\0'); |
720 | tw->count++; |
721 | return &lf->file; |
722 | } else if (node->type == TRIE_STRING) { |
723 | const struct trie_string *st = NODE(tw->t, off, trie_string); |
724 | |
725 | if (buf) |
726 | memcpy(buf + depth, st->string, st->stringlen); |
727 | depth += st->stringlen; |
728 | off = st->subnode; |
729 | } else if (node->type == TRIE_SWITCH) { |
730 | const struct trie_switch *sw = NODE(tw->t, off, trie_switch); |
731 | const char *chars = (const char *)&sw->sw[sw->len]; |
732 | |
733 | if (tw->nswitches >= tw->switchsize) { |
734 | tw->switchsize = tw->nswitches * 3 / 2 + 32; |
735 | tw->switches = sresize(tw->switches, tw->switchsize, |
736 | struct triewalk_switch); |
737 | } |
738 | |
739 | tw->switches[tw->nswitches].sw = sw; |
740 | tw->switches[tw->nswitches].pos = 1; |
741 | tw->switches[tw->nswitches].depth = depth; |
742 | tw->switches[tw->nswitches].count = tw->count + sw->sw[0].subcount; |
743 | off = sw->sw[0].subnode; |
744 | if (buf) |
745 | buf[depth++] = chars[0]; |
746 | tw->nswitches++; |
747 | } |
748 | } |
749 | } |
750 | void triewalk_free(triewalk *tw) |
751 | { |
752 | sfree(tw->switches); |
753 | sfree(tw); |
754 | } |
755 | |
756 | void trie_set_index_offset(void *t, off_t ptr) |
757 | { |
758 | ((struct trie_header *)t)->indexroot = ptr; |
759 | } |
760 | off_t trie_get_index_offset(const void *t) |
761 | { |
762 | return ((const struct trie_header *)t)->indexroot; |
763 | } |
256c29a2 |
764 | |
765 | void make_successor(char *pathbuf) |
766 | { |
767 | int len = strlen(pathbuf); |
768 | if (len > 0 && pathbuf[len-1] == pathsep) |
769 | len--; |
770 | pathbuf[len] = '\001'; |
771 | pathbuf[len+1] = '\0'; |
772 | } |