febd9a0f |
1 | /* |
d2371c81 |
2 | * tree234.c: reasonably generic counted 2-3-4 tree routines. |
3 | * |
4 | * This file is copyright 1999-2001 Simon Tatham. |
5 | * |
6 | * Permission is hereby granted, free of charge, to any person |
7 | * obtaining a copy of this software and associated documentation |
8 | * files (the "Software"), to deal in the Software without |
9 | * restriction, including without limitation the rights to use, |
10 | * copy, modify, merge, publish, distribute, sublicense, and/or |
11 | * sell copies of the Software, and to permit persons to whom the |
12 | * Software is furnished to do so, subject to the following |
13 | * conditions: |
14 | * |
15 | * The above copyright notice and this permission notice shall be |
16 | * included in all copies or substantial portions of the Software. |
17 | * |
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
19 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
20 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
21 | * NONINFRINGEMENT. IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR |
22 | * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF |
23 | * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
24 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
25 | * SOFTWARE. |
febd9a0f |
26 | */ |
27 | |
28 | #include <stdio.h> |
29 | #include <stdlib.h> |
d2371c81 |
30 | #include <assert.h> |
dcbde236 |
31 | |
3d88e64d |
32 | #include "puttymem.h" |
febd9a0f |
33 | #include "tree234.h" |
34 | |
febd9a0f |
35 | #ifdef TEST |
36 | #define LOG(x) (printf x) |
37 | #else |
cdd6c586 |
38 | #define LOG(x) |
febd9a0f |
39 | #endif |
40 | |
d2371c81 |
41 | typedef struct node234_Tag node234; |
42 | |
febd9a0f |
43 | struct tree234_Tag { |
44 | node234 *root; |
45 | cmpfn234 cmp; |
46 | }; |
47 | |
48 | struct node234_Tag { |
49 | node234 *parent; |
50 | node234 *kids[4]; |
d2371c81 |
51 | int counts[4]; |
febd9a0f |
52 | void *elems[3]; |
53 | }; |
54 | |
55 | /* |
56 | * Create a 2-3-4 tree. |
57 | */ |
32874aea |
58 | tree234 *newtree234(cmpfn234 cmp) |
59 | { |
3d88e64d |
60 | tree234 *ret = snew(tree234); |
febd9a0f |
61 | LOG(("created tree %p\n", ret)); |
62 | ret->root = NULL; |
63 | ret->cmp = cmp; |
64 | return ret; |
65 | } |
66 | |
67 | /* |
68 | * Free a 2-3-4 tree (not including freeing the elements). |
69 | */ |
32874aea |
70 | static void freenode234(node234 * n) |
71 | { |
febd9a0f |
72 | if (!n) |
73 | return; |
74 | freenode234(n->kids[0]); |
75 | freenode234(n->kids[1]); |
76 | freenode234(n->kids[2]); |
77 | freenode234(n->kids[3]); |
78 | sfree(n); |
79 | } |
32874aea |
80 | |
81 | void freetree234(tree234 * t) |
82 | { |
febd9a0f |
83 | freenode234(t->root); |
84 | sfree(t); |
85 | } |
86 | |
87 | /* |
d2371c81 |
88 | * Internal function to count a node. |
89 | */ |
32874aea |
90 | static int countnode234(node234 * n) |
91 | { |
d2371c81 |
92 | int count = 0; |
93 | int i; |
c404e5b3 |
94 | if (!n) |
95 | return 0; |
d2371c81 |
96 | for (i = 0; i < 4; i++) |
97 | count += n->counts[i]; |
98 | for (i = 0; i < 3; i++) |
99 | if (n->elems[i]) |
100 | count++; |
101 | return count; |
102 | } |
103 | |
104 | /* |
105 | * Count the elements in a tree. |
106 | */ |
32874aea |
107 | int count234(tree234 * t) |
108 | { |
d2371c81 |
109 | if (t->root) |
110 | return countnode234(t->root); |
111 | else |
112 | return 0; |
113 | } |
114 | |
115 | /* |
febd9a0f |
116 | * Add an element e to a 2-3-4 tree t. Returns e on success, or if |
117 | * an existing element compares equal, returns that. |
118 | */ |
32874aea |
119 | static void *add234_internal(tree234 * t, void *e, int index) |
120 | { |
febd9a0f |
121 | node234 *n, **np, *left, *right; |
122 | void *orig_e = e; |
d2371c81 |
123 | int c, lcount, rcount; |
febd9a0f |
124 | |
125 | LOG(("adding node %p to tree %p\n", e, t)); |
126 | if (t->root == NULL) { |
3d88e64d |
127 | t->root = snew(node234); |
febd9a0f |
128 | t->root->elems[1] = t->root->elems[2] = NULL; |
129 | t->root->kids[0] = t->root->kids[1] = NULL; |
130 | t->root->kids[2] = t->root->kids[3] = NULL; |
d2371c81 |
131 | t->root->counts[0] = t->root->counts[1] = 0; |
132 | t->root->counts[2] = t->root->counts[3] = 0; |
febd9a0f |
133 | t->root->parent = NULL; |
134 | t->root->elems[0] = e; |
135 | LOG((" created root %p\n", t->root)); |
136 | return orig_e; |
137 | } |
138 | |
139 | np = &t->root; |
140 | while (*np) { |
d2371c81 |
141 | int childnum; |
febd9a0f |
142 | n = *np; |
d2371c81 |
143 | LOG((" node %p: %p/%d [%p] %p/%d [%p] %p/%d [%p] %p/%d\n", |
144 | n, |
145 | n->kids[0], n->counts[0], n->elems[0], |
146 | n->kids[1], n->counts[1], n->elems[1], |
147 | n->kids[2], n->counts[2], n->elems[2], |
148 | n->kids[3], n->counts[3])); |
149 | if (index >= 0) { |
150 | if (!n->kids[0]) { |
151 | /* |
152 | * Leaf node. We want to insert at kid position |
153 | * equal to the index: |
154 | * |
155 | * 0 A 1 B 2 C 3 |
156 | */ |
157 | childnum = index; |
158 | } else { |
159 | /* |
160 | * Internal node. We always descend through it (add |
161 | * always starts at the bottom, never in the |
162 | * middle). |
163 | */ |
32874aea |
164 | do { /* this is a do ... while (0) to allow `break' */ |
d2371c81 |
165 | if (index <= n->counts[0]) { |
166 | childnum = 0; |
167 | break; |
168 | } |
169 | index -= n->counts[0] + 1; |
170 | if (index <= n->counts[1]) { |
171 | childnum = 1; |
172 | break; |
173 | } |
174 | index -= n->counts[1] + 1; |
175 | if (index <= n->counts[2]) { |
176 | childnum = 2; |
177 | break; |
178 | } |
179 | index -= n->counts[2] + 1; |
180 | if (index <= n->counts[3]) { |
181 | childnum = 3; |
182 | break; |
183 | } |
184 | return NULL; /* error: index out of range */ |
185 | } while (0); |
186 | } |
187 | } else { |
188 | if ((c = t->cmp(e, n->elems[0])) < 0) |
189 | childnum = 0; |
190 | else if (c == 0) |
32874aea |
191 | return n->elems[0]; /* already exists */ |
192 | else if (n->elems[1] == NULL |
193 | || (c = t->cmp(e, n->elems[1])) < 0) childnum = 1; |
d2371c81 |
194 | else if (c == 0) |
32874aea |
195 | return n->elems[1]; /* already exists */ |
196 | else if (n->elems[2] == NULL |
197 | || (c = t->cmp(e, n->elems[2])) < 0) childnum = 2; |
d2371c81 |
198 | else if (c == 0) |
32874aea |
199 | return n->elems[2]; /* already exists */ |
d2371c81 |
200 | else |
201 | childnum = 3; |
202 | } |
203 | np = &n->kids[childnum]; |
204 | LOG((" moving to child %d (%p)\n", childnum, *np)); |
febd9a0f |
205 | } |
206 | |
207 | /* |
208 | * We need to insert the new element in n at position np. |
209 | */ |
32874aea |
210 | left = NULL; |
211 | lcount = 0; |
212 | right = NULL; |
213 | rcount = 0; |
febd9a0f |
214 | while (n) { |
d2371c81 |
215 | LOG((" at %p: %p/%d [%p] %p/%d [%p] %p/%d [%p] %p/%d\n", |
216 | n, |
217 | n->kids[0], n->counts[0], n->elems[0], |
218 | n->kids[1], n->counts[1], n->elems[1], |
219 | n->kids[2], n->counts[2], n->elems[2], |
220 | n->kids[3], n->counts[3])); |
221 | LOG((" need to insert %p/%d [%p] %p/%d at position %d\n", |
222 | left, lcount, e, right, rcount, np - n->kids)); |
febd9a0f |
223 | if (n->elems[1] == NULL) { |
224 | /* |
225 | * Insert in a 2-node; simple. |
226 | */ |
227 | if (np == &n->kids[0]) { |
228 | LOG((" inserting on left of 2-node\n")); |
32874aea |
229 | n->kids[2] = n->kids[1]; |
230 | n->counts[2] = n->counts[1]; |
febd9a0f |
231 | n->elems[1] = n->elems[0]; |
32874aea |
232 | n->kids[1] = right; |
233 | n->counts[1] = rcount; |
febd9a0f |
234 | n->elems[0] = e; |
32874aea |
235 | n->kids[0] = left; |
236 | n->counts[0] = lcount; |
237 | } else { /* np == &n->kids[1] */ |
febd9a0f |
238 | LOG((" inserting on right of 2-node\n")); |
32874aea |
239 | n->kids[2] = right; |
240 | n->counts[2] = rcount; |
febd9a0f |
241 | n->elems[1] = e; |
32874aea |
242 | n->kids[1] = left; |
243 | n->counts[1] = lcount; |
febd9a0f |
244 | } |
32874aea |
245 | if (n->kids[0]) |
246 | n->kids[0]->parent = n; |
247 | if (n->kids[1]) |
248 | n->kids[1]->parent = n; |
249 | if (n->kids[2]) |
250 | n->kids[2]->parent = n; |
febd9a0f |
251 | LOG((" done\n")); |
252 | break; |
253 | } else if (n->elems[2] == NULL) { |
254 | /* |
255 | * Insert in a 3-node; simple. |
256 | */ |
257 | if (np == &n->kids[0]) { |
258 | LOG((" inserting on left of 3-node\n")); |
32874aea |
259 | n->kids[3] = n->kids[2]; |
260 | n->counts[3] = n->counts[2]; |
febd9a0f |
261 | n->elems[2] = n->elems[1]; |
32874aea |
262 | n->kids[2] = n->kids[1]; |
263 | n->counts[2] = n->counts[1]; |
febd9a0f |
264 | n->elems[1] = n->elems[0]; |
32874aea |
265 | n->kids[1] = right; |
266 | n->counts[1] = rcount; |
febd9a0f |
267 | n->elems[0] = e; |
32874aea |
268 | n->kids[0] = left; |
269 | n->counts[0] = lcount; |
febd9a0f |
270 | } else if (np == &n->kids[1]) { |
271 | LOG((" inserting in middle of 3-node\n")); |
32874aea |
272 | n->kids[3] = n->kids[2]; |
273 | n->counts[3] = n->counts[2]; |
febd9a0f |
274 | n->elems[2] = n->elems[1]; |
32874aea |
275 | n->kids[2] = right; |
276 | n->counts[2] = rcount; |
febd9a0f |
277 | n->elems[1] = e; |
32874aea |
278 | n->kids[1] = left; |
279 | n->counts[1] = lcount; |
280 | } else { /* np == &n->kids[2] */ |
febd9a0f |
281 | LOG((" inserting on right of 3-node\n")); |
32874aea |
282 | n->kids[3] = right; |
283 | n->counts[3] = rcount; |
febd9a0f |
284 | n->elems[2] = e; |
32874aea |
285 | n->kids[2] = left; |
286 | n->counts[2] = lcount; |
febd9a0f |
287 | } |
32874aea |
288 | if (n->kids[0]) |
289 | n->kids[0]->parent = n; |
290 | if (n->kids[1]) |
291 | n->kids[1]->parent = n; |
292 | if (n->kids[2]) |
293 | n->kids[2]->parent = n; |
294 | if (n->kids[3]) |
295 | n->kids[3]->parent = n; |
febd9a0f |
296 | LOG((" done\n")); |
297 | break; |
298 | } else { |
3d88e64d |
299 | node234 *m = snew(node234); |
febd9a0f |
300 | m->parent = n->parent; |
301 | LOG((" splitting a 4-node; created new node %p\n", m)); |
302 | /* |
303 | * Insert in a 4-node; split into a 2-node and a |
304 | * 3-node, and move focus up a level. |
305 | * |
306 | * I don't think it matters which way round we put the |
307 | * 2 and the 3. For simplicity, we'll put the 3 first |
308 | * always. |
309 | */ |
310 | if (np == &n->kids[0]) { |
32874aea |
311 | m->kids[0] = left; |
312 | m->counts[0] = lcount; |
febd9a0f |
313 | m->elems[0] = e; |
32874aea |
314 | m->kids[1] = right; |
315 | m->counts[1] = rcount; |
febd9a0f |
316 | m->elems[1] = n->elems[0]; |
32874aea |
317 | m->kids[2] = n->kids[1]; |
318 | m->counts[2] = n->counts[1]; |
febd9a0f |
319 | e = n->elems[1]; |
32874aea |
320 | n->kids[0] = n->kids[2]; |
321 | n->counts[0] = n->counts[2]; |
febd9a0f |
322 | n->elems[0] = n->elems[2]; |
32874aea |
323 | n->kids[1] = n->kids[3]; |
324 | n->counts[1] = n->counts[3]; |
febd9a0f |
325 | } else if (np == &n->kids[1]) { |
32874aea |
326 | m->kids[0] = n->kids[0]; |
327 | m->counts[0] = n->counts[0]; |
febd9a0f |
328 | m->elems[0] = n->elems[0]; |
32874aea |
329 | m->kids[1] = left; |
330 | m->counts[1] = lcount; |
febd9a0f |
331 | m->elems[1] = e; |
32874aea |
332 | m->kids[2] = right; |
333 | m->counts[2] = rcount; |
febd9a0f |
334 | e = n->elems[1]; |
32874aea |
335 | n->kids[0] = n->kids[2]; |
336 | n->counts[0] = n->counts[2]; |
febd9a0f |
337 | n->elems[0] = n->elems[2]; |
32874aea |
338 | n->kids[1] = n->kids[3]; |
339 | n->counts[1] = n->counts[3]; |
febd9a0f |
340 | } else if (np == &n->kids[2]) { |
32874aea |
341 | m->kids[0] = n->kids[0]; |
342 | m->counts[0] = n->counts[0]; |
febd9a0f |
343 | m->elems[0] = n->elems[0]; |
32874aea |
344 | m->kids[1] = n->kids[1]; |
345 | m->counts[1] = n->counts[1]; |
febd9a0f |
346 | m->elems[1] = n->elems[1]; |
32874aea |
347 | m->kids[2] = left; |
348 | m->counts[2] = lcount; |
febd9a0f |
349 | /* e = e; */ |
32874aea |
350 | n->kids[0] = right; |
351 | n->counts[0] = rcount; |
febd9a0f |
352 | n->elems[0] = n->elems[2]; |
32874aea |
353 | n->kids[1] = n->kids[3]; |
354 | n->counts[1] = n->counts[3]; |
355 | } else { /* np == &n->kids[3] */ |
356 | m->kids[0] = n->kids[0]; |
357 | m->counts[0] = n->counts[0]; |
febd9a0f |
358 | m->elems[0] = n->elems[0]; |
32874aea |
359 | m->kids[1] = n->kids[1]; |
360 | m->counts[1] = n->counts[1]; |
febd9a0f |
361 | m->elems[1] = n->elems[1]; |
32874aea |
362 | m->kids[2] = n->kids[2]; |
363 | m->counts[2] = n->counts[2]; |
364 | n->kids[0] = left; |
365 | n->counts[0] = lcount; |
febd9a0f |
366 | n->elems[0] = e; |
32874aea |
367 | n->kids[1] = right; |
368 | n->counts[1] = rcount; |
febd9a0f |
369 | e = n->elems[2]; |
370 | } |
371 | m->kids[3] = n->kids[3] = n->kids[2] = NULL; |
d2371c81 |
372 | m->counts[3] = n->counts[3] = n->counts[2] = 0; |
febd9a0f |
373 | m->elems[2] = n->elems[2] = n->elems[1] = NULL; |
32874aea |
374 | if (m->kids[0]) |
375 | m->kids[0]->parent = m; |
376 | if (m->kids[1]) |
377 | m->kids[1]->parent = m; |
378 | if (m->kids[2]) |
379 | m->kids[2]->parent = m; |
380 | if (n->kids[0]) |
381 | n->kids[0]->parent = n; |
382 | if (n->kids[1]) |
383 | n->kids[1]->parent = n; |
d2371c81 |
384 | LOG((" left (%p): %p/%d [%p] %p/%d [%p] %p/%d\n", m, |
385 | m->kids[0], m->counts[0], m->elems[0], |
386 | m->kids[1], m->counts[1], m->elems[1], |
387 | m->kids[2], m->counts[2])); |
388 | LOG((" right (%p): %p/%d [%p] %p/%d\n", n, |
389 | n->kids[0], n->counts[0], n->elems[0], |
390 | n->kids[1], n->counts[1])); |
32874aea |
391 | left = m; |
392 | lcount = countnode234(left); |
393 | right = n; |
394 | rcount = countnode234(right); |
febd9a0f |
395 | } |
396 | if (n->parent) |
397 | np = (n->parent->kids[0] == n ? &n->parent->kids[0] : |
398 | n->parent->kids[1] == n ? &n->parent->kids[1] : |
399 | n->parent->kids[2] == n ? &n->parent->kids[2] : |
400 | &n->parent->kids[3]); |
401 | n = n->parent; |
402 | } |
403 | |
404 | /* |
405 | * If we've come out of here by `break', n will still be |
d2371c81 |
406 | * non-NULL and all we need to do is go back up the tree |
407 | * updating counts. If we've come here because n is NULL, we |
408 | * need to create a new root for the tree because the old one |
409 | * has just split into two. */ |
410 | if (n) { |
411 | while (n->parent) { |
412 | int count = countnode234(n); |
413 | int childnum; |
414 | childnum = (n->parent->kids[0] == n ? 0 : |
415 | n->parent->kids[1] == n ? 1 : |
416 | n->parent->kids[2] == n ? 2 : 3); |
417 | n->parent->counts[childnum] = count; |
418 | n = n->parent; |
419 | } |
420 | } else { |
febd9a0f |
421 | LOG((" root is overloaded, split into two\n")); |
3d88e64d |
422 | t->root = snew(node234); |
32874aea |
423 | t->root->kids[0] = left; |
424 | t->root->counts[0] = lcount; |
febd9a0f |
425 | t->root->elems[0] = e; |
32874aea |
426 | t->root->kids[1] = right; |
427 | t->root->counts[1] = rcount; |
febd9a0f |
428 | t->root->elems[1] = NULL; |
32874aea |
429 | t->root->kids[2] = NULL; |
430 | t->root->counts[2] = 0; |
febd9a0f |
431 | t->root->elems[2] = NULL; |
32874aea |
432 | t->root->kids[3] = NULL; |
433 | t->root->counts[3] = 0; |
febd9a0f |
434 | t->root->parent = NULL; |
32874aea |
435 | if (t->root->kids[0]) |
436 | t->root->kids[0]->parent = t->root; |
437 | if (t->root->kids[1]) |
438 | t->root->kids[1]->parent = t->root; |
d2371c81 |
439 | LOG((" new root is %p/%d [%p] %p/%d\n", |
440 | t->root->kids[0], t->root->counts[0], |
32874aea |
441 | t->root->elems[0], t->root->kids[1], t->root->counts[1])); |
febd9a0f |
442 | } |
443 | |
444 | return orig_e; |
445 | } |
446 | |
32874aea |
447 | void *add234(tree234 * t, void *e) |
448 | { |
d2371c81 |
449 | if (!t->cmp) /* tree is unsorted */ |
450 | return NULL; |
451 | |
452 | return add234_internal(t, e, -1); |
453 | } |
32874aea |
454 | void *addpos234(tree234 * t, void *e, int index) |
455 | { |
d2371c81 |
456 | if (index < 0 || /* index out of range */ |
457 | t->cmp) /* tree is sorted */ |
458 | return NULL; /* return failure */ |
459 | |
32874aea |
460 | return add234_internal(t, e, index); /* this checks the upper bound */ |
d2371c81 |
461 | } |
462 | |
febd9a0f |
463 | /* |
d2371c81 |
464 | * Look up the element at a given numeric index in a 2-3-4 tree. |
465 | * Returns NULL if the index is out of range. |
febd9a0f |
466 | */ |
32874aea |
467 | void *index234(tree234 * t, int index) |
468 | { |
febd9a0f |
469 | node234 *n; |
febd9a0f |
470 | |
d2371c81 |
471 | if (!t->root) |
472 | return NULL; /* tree is empty */ |
febd9a0f |
473 | |
d2371c81 |
474 | if (index < 0 || index >= countnode234(t->root)) |
475 | return NULL; /* out of range */ |
febd9a0f |
476 | |
477 | n = t->root; |
32874aea |
478 | |
febd9a0f |
479 | while (n) { |
d2371c81 |
480 | if (index < n->counts[0]) |
febd9a0f |
481 | n = n->kids[0]; |
d2371c81 |
482 | else if (index -= n->counts[0] + 1, index < 0) |
febd9a0f |
483 | return n->elems[0]; |
d2371c81 |
484 | else if (index < n->counts[1]) |
febd9a0f |
485 | n = n->kids[1]; |
d2371c81 |
486 | else if (index -= n->counts[1] + 1, index < 0) |
febd9a0f |
487 | return n->elems[1]; |
d2371c81 |
488 | else if (index < n->counts[2]) |
febd9a0f |
489 | n = n->kids[2]; |
d2371c81 |
490 | else if (index -= n->counts[2] + 1, index < 0) |
febd9a0f |
491 | return n->elems[2]; |
492 | else |
493 | n = n->kids[3]; |
494 | } |
495 | |
d2371c81 |
496 | /* We shouldn't ever get here. I wonder how we did. */ |
497 | return NULL; |
498 | } |
499 | |
500 | /* |
501 | * Find an element e in a sorted 2-3-4 tree t. Returns NULL if not |
502 | * found. e is always passed as the first argument to cmp, so cmp |
503 | * can be an asymmetric function if desired. cmp can also be passed |
504 | * as NULL, in which case the compare function from the tree proper |
505 | * will be used. |
506 | */ |
32874aea |
507 | void *findrelpos234(tree234 * t, void *e, cmpfn234 cmp, |
508 | int relation, int *index) |
509 | { |
d2371c81 |
510 | node234 *n; |
511 | void *ret; |
512 | int c; |
513 | int idx, ecount, kcount, cmpret; |
514 | |
515 | if (t->root == NULL) |
516 | return NULL; |
517 | |
518 | if (cmp == NULL) |
519 | cmp = t->cmp; |
520 | |
521 | n = t->root; |
febd9a0f |
522 | /* |
d2371c81 |
523 | * Attempt to find the element itself. |
febd9a0f |
524 | */ |
d2371c81 |
525 | idx = 0; |
526 | ecount = -1; |
527 | /* |
528 | * Prepare a fake `cmp' result if e is NULL. |
529 | */ |
530 | cmpret = 0; |
531 | if (e == NULL) { |
532 | assert(relation == REL234_LT || relation == REL234_GT); |
533 | if (relation == REL234_LT) |
534 | cmpret = +1; /* e is a max: always greater */ |
535 | else if (relation == REL234_GT) |
536 | cmpret = -1; /* e is a min: always smaller */ |
537 | } |
538 | while (1) { |
539 | for (kcount = 0; kcount < 4; kcount++) { |
540 | if (kcount >= 3 || n->elems[kcount] == NULL || |
541 | (c = cmpret ? cmpret : cmp(e, n->elems[kcount])) < 0) { |
542 | break; |
543 | } |
32874aea |
544 | if (n->kids[kcount]) |
545 | idx += n->counts[kcount]; |
d2371c81 |
546 | if (c == 0) { |
547 | ecount = kcount; |
548 | break; |
549 | } |
550 | idx++; |
551 | } |
552 | if (ecount >= 0) |
553 | break; |
554 | if (n->kids[kcount]) |
555 | n = n->kids[kcount]; |
556 | else |
557 | break; |
558 | } |
559 | |
560 | if (ecount >= 0) { |
561 | /* |
562 | * We have found the element we're looking for. It's |
563 | * n->elems[ecount], at tree index idx. If our search |
564 | * relation is EQ, LE or GE we can now go home. |
565 | */ |
566 | if (relation != REL234_LT && relation != REL234_GT) { |
32874aea |
567 | if (index) |
568 | *index = idx; |
d2371c81 |
569 | return n->elems[ecount]; |
570 | } |
571 | |
572 | /* |
573 | * Otherwise, we'll do an indexed lookup for the previous |
574 | * or next element. (It would be perfectly possible to |
575 | * implement these search types in a non-counted tree by |
576 | * going back up from where we are, but far more fiddly.) |
577 | */ |
578 | if (relation == REL234_LT) |
579 | idx--; |
580 | else |
581 | idx++; |
582 | } else { |
583 | /* |
584 | * We've found our way to the bottom of the tree and we |
585 | * know where we would insert this node if we wanted to: |
586 | * we'd put it in in place of the (empty) subtree |
587 | * n->kids[kcount], and it would have index idx |
588 | * |
589 | * But the actual element isn't there. So if our search |
590 | * relation is EQ, we're doomed. |
591 | */ |
592 | if (relation == REL234_EQ) |
593 | return NULL; |
594 | |
595 | /* |
596 | * Otherwise, we must do an index lookup for index idx-1 |
597 | * (if we're going left - LE or LT) or index idx (if we're |
598 | * going right - GE or GT). |
599 | */ |
600 | if (relation == REL234_LT || relation == REL234_LE) { |
601 | idx--; |
602 | } |
603 | } |
604 | |
605 | /* |
606 | * We know the index of the element we want; just call index234 |
607 | * to do the rest. This will return NULL if the index is out of |
608 | * bounds, which is exactly what we want. |
609 | */ |
610 | ret = index234(t, idx); |
32874aea |
611 | if (ret && index) |
612 | *index = idx; |
d2371c81 |
613 | return ret; |
614 | } |
32874aea |
615 | void *find234(tree234 * t, void *e, cmpfn234 cmp) |
616 | { |
d2371c81 |
617 | return findrelpos234(t, e, cmp, REL234_EQ, NULL); |
618 | } |
32874aea |
619 | void *findrel234(tree234 * t, void *e, cmpfn234 cmp, int relation) |
620 | { |
d2371c81 |
621 | return findrelpos234(t, e, cmp, relation, NULL); |
622 | } |
32874aea |
623 | void *findpos234(tree234 * t, void *e, cmpfn234 cmp, int *index) |
624 | { |
d2371c81 |
625 | return findrelpos234(t, e, cmp, REL234_EQ, index); |
febd9a0f |
626 | } |
627 | |
628 | /* |
629 | * Delete an element e in a 2-3-4 tree. Does not free the element, |
630 | * merely removes all links to it from the tree nodes. |
631 | */ |
32874aea |
632 | static void *delpos234_internal(tree234 * t, int index) |
633 | { |
febd9a0f |
634 | node234 *n; |
d2371c81 |
635 | void *retval; |
febd9a0f |
636 | int ei = -1; |
637 | |
d2371c81 |
638 | retval = 0; |
639 | |
febd9a0f |
640 | n = t->root; |
d2371c81 |
641 | LOG(("deleting item %d from tree %p\n", index, t)); |
febd9a0f |
642 | while (1) { |
643 | while (n) { |
febd9a0f |
644 | int ki; |
645 | node234 *sub; |
646 | |
32874aea |
647 | LOG( |
648 | (" node %p: %p/%d [%p] %p/%d [%p] %p/%d [%p] %p/%d index=%d\n", |
649 | n, n->kids[0], n->counts[0], n->elems[0], n->kids[1], |
650 | n->counts[1], n->elems[1], n->kids[2], n->counts[2], |
651 | n->elems[2], n->kids[3], n->counts[3], index)); |
d2371c81 |
652 | if (index < n->counts[0]) { |
febd9a0f |
653 | ki = 0; |
32874aea |
654 | } else if (index -= n->counts[0] + 1, index < 0) { |
655 | ei = 0; |
656 | break; |
d2371c81 |
657 | } else if (index < n->counts[1]) { |
febd9a0f |
658 | ki = 1; |
32874aea |
659 | } else if (index -= n->counts[1] + 1, index < 0) { |
660 | ei = 1; |
661 | break; |
d2371c81 |
662 | } else if (index < n->counts[2]) { |
febd9a0f |
663 | ki = 2; |
32874aea |
664 | } else if (index -= n->counts[2] + 1, index < 0) { |
665 | ei = 2; |
666 | break; |
febd9a0f |
667 | } else { |
668 | ki = 3; |
669 | } |
670 | /* |
671 | * Recurse down to subtree ki. If it has only one element, |
672 | * we have to do some transformation to start with. |
673 | */ |
674 | LOG((" moving to subtree %d\n", ki)); |
675 | sub = n->kids[ki]; |
676 | if (!sub->elems[1]) { |
677 | LOG((" subtree has only one element!\n", ki)); |
32874aea |
678 | if (ki > 0 && n->kids[ki - 1]->elems[1]) { |
febd9a0f |
679 | /* |
680 | * Case 3a, left-handed variant. Child ki has |
681 | * only one element, but child ki-1 has two or |
682 | * more. So we need to move a subtree from ki-1 |
683 | * to ki. |
684 | * |
685 | * . C . . B . |
686 | * / \ -> / \ |
687 | * [more] a A b B c d D e [more] a A b c C d D e |
688 | */ |
32874aea |
689 | node234 *sib = n->kids[ki - 1]; |
febd9a0f |
690 | int lastelem = (sib->elems[2] ? 2 : |
691 | sib->elems[1] ? 1 : 0); |
692 | sub->kids[2] = sub->kids[1]; |
d2371c81 |
693 | sub->counts[2] = sub->counts[1]; |
febd9a0f |
694 | sub->elems[1] = sub->elems[0]; |
695 | sub->kids[1] = sub->kids[0]; |
d2371c81 |
696 | sub->counts[1] = sub->counts[0]; |
32874aea |
697 | sub->elems[0] = n->elems[ki - 1]; |
698 | sub->kids[0] = sib->kids[lastelem + 1]; |
699 | sub->counts[0] = sib->counts[lastelem + 1]; |
700 | if (sub->kids[0]) |
701 | sub->kids[0]->parent = sub; |
702 | n->elems[ki - 1] = sib->elems[lastelem]; |
703 | sib->kids[lastelem + 1] = NULL; |
704 | sib->counts[lastelem + 1] = 0; |
febd9a0f |
705 | sib->elems[lastelem] = NULL; |
d2371c81 |
706 | n->counts[ki] = countnode234(sub); |
febd9a0f |
707 | LOG((" case 3a left\n")); |
32874aea |
708 | LOG( |
709 | (" index and left subtree count before adjustment: %d, %d\n", |
710 | index, n->counts[ki - 1])); |
711 | index += n->counts[ki - 1]; |
712 | n->counts[ki - 1] = countnode234(sib); |
713 | index -= n->counts[ki - 1]; |
714 | LOG( |
715 | (" index and left subtree count after adjustment: %d, %d\n", |
716 | index, n->counts[ki - 1])); |
717 | } else if (ki < 3 && n->kids[ki + 1] |
718 | && n->kids[ki + 1]->elems[1]) { |
febd9a0f |
719 | /* |
720 | * Case 3a, right-handed variant. ki has only |
721 | * one element but ki+1 has two or more. Move a |
722 | * subtree from ki+1 to ki. |
723 | * |
724 | * . B . . C . |
725 | * / \ -> / \ |
726 | * a A b c C d D e [more] a A b B c d D e [more] |
727 | */ |
32874aea |
728 | node234 *sib = n->kids[ki + 1]; |
febd9a0f |
729 | int j; |
730 | sub->elems[1] = n->elems[ki]; |
731 | sub->kids[2] = sib->kids[0]; |
d2371c81 |
732 | sub->counts[2] = sib->counts[0]; |
32874aea |
733 | if (sub->kids[2]) |
734 | sub->kids[2]->parent = sub; |
febd9a0f |
735 | n->elems[ki] = sib->elems[0]; |
736 | sib->kids[0] = sib->kids[1]; |
d2371c81 |
737 | sib->counts[0] = sib->counts[1]; |
32874aea |
738 | for (j = 0; j < 2 && sib->elems[j + 1]; j++) { |
739 | sib->kids[j + 1] = sib->kids[j + 2]; |
740 | sib->counts[j + 1] = sib->counts[j + 2]; |
741 | sib->elems[j] = sib->elems[j + 1]; |
febd9a0f |
742 | } |
32874aea |
743 | sib->kids[j + 1] = NULL; |
744 | sib->counts[j + 1] = 0; |
febd9a0f |
745 | sib->elems[j] = NULL; |
d2371c81 |
746 | n->counts[ki] = countnode234(sub); |
32874aea |
747 | n->counts[ki + 1] = countnode234(sib); |
febd9a0f |
748 | LOG((" case 3a right\n")); |
749 | } else { |
750 | /* |
751 | * Case 3b. ki has only one element, and has no |
752 | * neighbour with more than one. So pick a |
753 | * neighbour and merge it with ki, taking an |
754 | * element down from n to go in the middle. |
755 | * |
756 | * . B . . |
757 | * / \ -> | |
758 | * a A b c C d a A b B c C d |
759 | * |
760 | * (Since at all points we have avoided |
761 | * descending to a node with only one element, |
762 | * we can be sure that n is not reduced to |
763 | * nothingness by this move, _unless_ it was |
764 | * the very first node, ie the root of the |
765 | * tree. In that case we remove the now-empty |
766 | * root and replace it with its single large |
767 | * child as shown.) |
768 | */ |
769 | node234 *sib; |
770 | int j; |
771 | |
d2371c81 |
772 | if (ki > 0) { |
febd9a0f |
773 | ki--; |
d2371c81 |
774 | index += n->counts[ki] + 1; |
775 | } |
febd9a0f |
776 | sib = n->kids[ki]; |
32874aea |
777 | sub = n->kids[ki + 1]; |
febd9a0f |
778 | |
779 | sub->kids[3] = sub->kids[1]; |
d2371c81 |
780 | sub->counts[3] = sub->counts[1]; |
febd9a0f |
781 | sub->elems[2] = sub->elems[0]; |
782 | sub->kids[2] = sub->kids[0]; |
d2371c81 |
783 | sub->counts[2] = sub->counts[0]; |
febd9a0f |
784 | sub->elems[1] = n->elems[ki]; |
785 | sub->kids[1] = sib->kids[1]; |
d2371c81 |
786 | sub->counts[1] = sib->counts[1]; |
32874aea |
787 | if (sub->kids[1]) |
788 | sub->kids[1]->parent = sub; |
febd9a0f |
789 | sub->elems[0] = sib->elems[0]; |
790 | sub->kids[0] = sib->kids[0]; |
d2371c81 |
791 | sub->counts[0] = sib->counts[0]; |
32874aea |
792 | if (sub->kids[0]) |
793 | sub->kids[0]->parent = sub; |
febd9a0f |
794 | |
32874aea |
795 | n->counts[ki + 1] = countnode234(sub); |
d2371c81 |
796 | |
febd9a0f |
797 | sfree(sib); |
798 | |
799 | /* |
800 | * That's built the big node in sub. Now we |
801 | * need to remove the reference to sib in n. |
802 | */ |
32874aea |
803 | for (j = ki; j < 3 && n->kids[j + 1]; j++) { |
804 | n->kids[j] = n->kids[j + 1]; |
805 | n->counts[j] = n->counts[j + 1]; |
806 | n->elems[j] = j < 2 ? n->elems[j + 1] : NULL; |
febd9a0f |
807 | } |
808 | n->kids[j] = NULL; |
d2371c81 |
809 | n->counts[j] = 0; |
32874aea |
810 | if (j < 3) |
811 | n->elems[j] = NULL; |
2d56b16f |
812 | LOG((" case 3b ki=%d\n", ki)); |
febd9a0f |
813 | |
814 | if (!n->elems[0]) { |
815 | /* |
816 | * The root is empty and needs to be |
817 | * removed. |
818 | */ |
819 | LOG((" shifting root!\n")); |
820 | t->root = sub; |
821 | sub->parent = NULL; |
822 | sfree(n); |
823 | } |
824 | } |
825 | } |
826 | n = sub; |
827 | } |
d2371c81 |
828 | if (!retval) |
829 | retval = n->elems[ei]; |
830 | |
32874aea |
831 | if (ei == -1) |
d2371c81 |
832 | return NULL; /* although this shouldn't happen */ |
febd9a0f |
833 | |
834 | /* |
835 | * Treat special case: this is the one remaining item in |
836 | * the tree. n is the tree root (no parent), has one |
837 | * element (no elems[1]), and has no kids (no kids[0]). |
838 | */ |
839 | if (!n->parent && !n->elems[1] && !n->kids[0]) { |
840 | LOG((" removed last element in tree\n")); |
841 | sfree(n); |
842 | t->root = NULL; |
d2371c81 |
843 | return retval; |
febd9a0f |
844 | } |
845 | |
846 | /* |
847 | * Now we have the element we want, as n->elems[ei], and we |
848 | * have also arranged for that element not to be the only |
849 | * one in its node. So... |
850 | */ |
851 | |
852 | if (!n->kids[0] && n->elems[1]) { |
853 | /* |
854 | * Case 1. n is a leaf node with more than one element, |
855 | * so it's _really easy_. Just delete the thing and |
856 | * we're done. |
857 | */ |
858 | int i; |
859 | LOG((" case 1\n")); |
32874aea |
860 | for (i = ei; i < 2 && n->elems[i + 1]; i++) |
861 | n->elems[i] = n->elems[i + 1]; |
febd9a0f |
862 | n->elems[i] = NULL; |
d2371c81 |
863 | /* |
864 | * Having done that to the leaf node, we now go back up |
865 | * the tree fixing the counts. |
866 | */ |
867 | while (n->parent) { |
868 | int childnum; |
869 | childnum = (n->parent->kids[0] == n ? 0 : |
870 | n->parent->kids[1] == n ? 1 : |
871 | n->parent->kids[2] == n ? 2 : 3); |
872 | n->parent->counts[childnum]--; |
873 | n = n->parent; |
874 | } |
875 | return retval; /* finished! */ |
febd9a0f |
876 | } else if (n->kids[ei]->elems[1]) { |
877 | /* |
878 | * Case 2a. n is an internal node, and the root of the |
879 | * subtree to the left of e has more than one element. |
880 | * So find the predecessor p to e (ie the largest node |
881 | * in that subtree), place it where e currently is, and |
882 | * then start the deletion process over again on the |
883 | * subtree with p as target. |
884 | */ |
885 | node234 *m = n->kids[ei]; |
886 | void *target; |
887 | LOG((" case 2a\n")); |
888 | while (m->kids[0]) { |
889 | m = (m->kids[3] ? m->kids[3] : |
890 | m->kids[2] ? m->kids[2] : |
32874aea |
891 | m->kids[1] ? m->kids[1] : m->kids[0]); |
febd9a0f |
892 | } |
893 | target = (m->elems[2] ? m->elems[2] : |
894 | m->elems[1] ? m->elems[1] : m->elems[0]); |
895 | n->elems[ei] = target; |
32874aea |
896 | index = n->counts[ei] - 1; |
febd9a0f |
897 | n = n->kids[ei]; |
32874aea |
898 | } else if (n->kids[ei + 1]->elems[1]) { |
febd9a0f |
899 | /* |
900 | * Case 2b, symmetric to 2a but s/left/right/ and |
901 | * s/predecessor/successor/. (And s/largest/smallest/). |
902 | */ |
32874aea |
903 | node234 *m = n->kids[ei + 1]; |
febd9a0f |
904 | void *target; |
905 | LOG((" case 2b\n")); |
906 | while (m->kids[0]) { |
907 | m = m->kids[0]; |
908 | } |
909 | target = m->elems[0]; |
910 | n->elems[ei] = target; |
32874aea |
911 | n = n->kids[ei + 1]; |
d2371c81 |
912 | index = 0; |
febd9a0f |
913 | } else { |
914 | /* |
915 | * Case 2c. n is an internal node, and the subtrees to |
916 | * the left and right of e both have only one element. |
917 | * So combine the two subnodes into a single big node |
918 | * with their own elements on the left and right and e |
919 | * in the middle, then restart the deletion process on |
920 | * that subtree, with e still as target. |
921 | */ |
32874aea |
922 | node234 *a = n->kids[ei], *b = n->kids[ei + 1]; |
febd9a0f |
923 | int j; |
924 | |
925 | LOG((" case 2c\n")); |
926 | a->elems[1] = n->elems[ei]; |
927 | a->kids[2] = b->kids[0]; |
d2371c81 |
928 | a->counts[2] = b->counts[0]; |
32874aea |
929 | if (a->kids[2]) |
930 | a->kids[2]->parent = a; |
febd9a0f |
931 | a->elems[2] = b->elems[0]; |
932 | a->kids[3] = b->kids[1]; |
d2371c81 |
933 | a->counts[3] = b->counts[1]; |
32874aea |
934 | if (a->kids[3]) |
935 | a->kids[3]->parent = a; |
febd9a0f |
936 | sfree(b); |
d2371c81 |
937 | n->counts[ei] = countnode234(a); |
febd9a0f |
938 | /* |
939 | * That's built the big node in a, and destroyed b. Now |
940 | * remove the reference to b (and e) in n. |
941 | */ |
32874aea |
942 | for (j = ei; j < 2 && n->elems[j + 1]; j++) { |
943 | n->elems[j] = n->elems[j + 1]; |
944 | n->kids[j + 1] = n->kids[j + 2]; |
945 | n->counts[j + 1] = n->counts[j + 2]; |
febd9a0f |
946 | } |
947 | n->elems[j] = NULL; |
32874aea |
948 | n->kids[j + 1] = NULL; |
949 | n->counts[j + 1] = 0; |
950 | /* |
951 | * It's possible, in this case, that we've just removed |
952 | * the only element in the root of the tree. If so, |
953 | * shift the root. |
954 | */ |
955 | if (n->elems[0] == NULL) { |
956 | LOG((" shifting root!\n")); |
957 | t->root = a; |
958 | a->parent = NULL; |
959 | sfree(n); |
960 | } |
febd9a0f |
961 | /* |
962 | * Now go round the deletion process again, with n |
963 | * pointing at the new big node and e still the same. |
964 | */ |
965 | n = a; |
d2371c81 |
966 | index = a->counts[0] + a->counts[1] + 1; |
febd9a0f |
967 | } |
968 | } |
969 | } |
32874aea |
970 | void *delpos234(tree234 * t, int index) |
971 | { |
d2371c81 |
972 | if (index < 0 || index >= countnode234(t->root)) |
febd9a0f |
973 | return NULL; |
d2371c81 |
974 | return delpos234_internal(t, index); |
febd9a0f |
975 | } |
32874aea |
976 | void *del234(tree234 * t, void *e) |
977 | { |
d2371c81 |
978 | int index; |
979 | if (!findrelpos234(t, e, NULL, REL234_EQ, &index)) |
980 | return NULL; /* it wasn't in there anyway */ |
32874aea |
981 | return delpos234_internal(t, index); /* it's there; delete it. */ |
febd9a0f |
982 | } |
983 | |
984 | #ifdef TEST |
985 | |
2d56b16f |
986 | /* |
987 | * Test code for the 2-3-4 tree. This code maintains an alternative |
988 | * representation of the data in the tree, in an array (using the |
989 | * obvious and slow insert and delete functions). After each tree |
7aa7c43a |
990 | * operation, the verify() function is called, which ensures all |
d2371c81 |
991 | * the tree properties are preserved: |
992 | * - node->child->parent always equals node |
993 | * - tree->root->parent always equals NULL |
994 | * - number of kids == 0 or number of elements + 1; |
995 | * - tree has the same depth everywhere |
996 | * - every node has at least one element |
997 | * - subtree element counts are accurate |
998 | * - any NULL kid pointer is accompanied by a zero count |
999 | * - in a sorted tree: ordering property between elements of a |
1000 | * node and elements of its children is preserved |
1001 | * and also ensures the list represented by the tree is the same |
1002 | * list it should be. (This last check also doubly verifies the |
1003 | * ordering properties, because the `same list it should be' is by |
1004 | * definition correctly ordered. It also ensures all nodes are |
1005 | * distinct, because the enum functions would get caught in a loop |
1006 | * if not.) |
2d56b16f |
1007 | */ |
1008 | |
1009 | #include <stdarg.h> |
1010 | |
1011 | /* |
1012 | * Error reporting function. |
1013 | */ |
32874aea |
1014 | void error(char *fmt, ...) |
1015 | { |
2d56b16f |
1016 | va_list ap; |
1017 | printf("ERROR: "); |
1018 | va_start(ap, fmt); |
1019 | vfprintf(stdout, fmt, ap); |
1020 | va_end(ap); |
1021 | printf("\n"); |
1022 | } |
1023 | |
1024 | /* The array representation of the data. */ |
1025 | void **array; |
1026 | int arraylen, arraysize; |
1027 | cmpfn234 cmp; |
1028 | |
1029 | /* The tree representation of the same data. */ |
1030 | tree234 *tree; |
1031 | |
1032 | typedef struct { |
1033 | int treedepth; |
1034 | int elemcount; |
1035 | } chkctx; |
1036 | |
32874aea |
1037 | int chknode(chkctx * ctx, int level, node234 * node, |
1038 | void *lowbound, void *highbound) |
1039 | { |
2d56b16f |
1040 | int nkids, nelems; |
1041 | int i; |
d2371c81 |
1042 | int count; |
2d56b16f |
1043 | |
1044 | /* Count the non-NULL kids. */ |
1045 | for (nkids = 0; nkids < 4 && node->kids[nkids]; nkids++); |
1046 | /* Ensure no kids beyond the first NULL are non-NULL. */ |
1047 | for (i = nkids; i < 4; i++) |
32874aea |
1048 | if (node->kids[i]) { |
1049 | error("node %p: nkids=%d but kids[%d] non-NULL", |
1050 | node, nkids, i); |
1051 | } else if (node->counts[i]) { |
1052 | error("node %p: kids[%d] NULL but count[%d]=%d nonzero", |
1053 | node, i, i, node->counts[i]); |
d2371c81 |
1054 | } |
2d56b16f |
1055 | |
1056 | /* Count the non-NULL elements. */ |
1057 | for (nelems = 0; nelems < 3 && node->elems[nelems]; nelems++); |
1058 | /* Ensure no elements beyond the first NULL are non-NULL. */ |
1059 | for (i = nelems; i < 3; i++) |
32874aea |
1060 | if (node->elems[i]) { |
1061 | error("node %p: nelems=%d but elems[%d] non-NULL", |
1062 | node, nelems, i); |
1063 | } |
2d56b16f |
1064 | |
1065 | if (nkids == 0) { |
32874aea |
1066 | /* |
1067 | * If nkids==0, this is a leaf node; verify that the tree |
1068 | * depth is the same everywhere. |
1069 | */ |
1070 | if (ctx->treedepth < 0) |
1071 | ctx->treedepth = level; /* we didn't know the depth yet */ |
1072 | else if (ctx->treedepth != level) |
1073 | error("node %p: leaf at depth %d, previously seen depth %d", |
1074 | node, level, ctx->treedepth); |
2d56b16f |
1075 | } else { |
32874aea |
1076 | /* |
1077 | * If nkids != 0, then it should be nelems+1, unless nelems |
1078 | * is 0 in which case nkids should also be 0 (and so we |
1079 | * shouldn't be in this condition at all). |
1080 | */ |
1081 | int shouldkids = (nelems ? nelems + 1 : 0); |
1082 | if (nkids != shouldkids) { |
1083 | error("node %p: %d elems should mean %d kids but has %d", |
1084 | node, nelems, shouldkids, nkids); |
1085 | } |
2d56b16f |
1086 | } |
1087 | |
1088 | /* |
1089 | * nelems should be at least 1. |
1090 | */ |
1091 | if (nelems == 0) { |
32874aea |
1092 | error("node %p: no elems", node, nkids); |
2d56b16f |
1093 | } |
1094 | |
1095 | /* |
d2371c81 |
1096 | * Add nelems to the running element count of the whole tree. |
2d56b16f |
1097 | */ |
1098 | ctx->elemcount += nelems; |
1099 | |
1100 | /* |
1101 | * Check ordering property: all elements should be strictly > |
1102 | * lowbound, strictly < highbound, and strictly < each other in |
1103 | * sequence. (lowbound and highbound are NULL at edges of tree |
1104 | * - both NULL at root node - and NULL is considered to be < |
1105 | * everything and > everything. IYSWIM.) |
1106 | */ |
d2371c81 |
1107 | if (cmp) { |
1108 | for (i = -1; i < nelems; i++) { |
1109 | void *lower = (i == -1 ? lowbound : node->elems[i]); |
32874aea |
1110 | void *higher = |
1111 | (i + 1 == nelems ? highbound : node->elems[i + 1]); |
d2371c81 |
1112 | if (lower && higher && cmp(lower, higher) >= 0) { |
1113 | error("node %p: kid comparison [%d=%s,%d=%s] failed", |
32874aea |
1114 | node, i, lower, i + 1, higher); |
d2371c81 |
1115 | } |
1116 | } |
2d56b16f |
1117 | } |
1118 | |
1119 | /* |
1120 | * Check parent pointers: all non-NULL kids should have a |
1121 | * parent pointer coming back to this node. |
1122 | */ |
1123 | for (i = 0; i < nkids; i++) |
32874aea |
1124 | if (node->kids[i]->parent != node) { |
1125 | error("node %p kid %d: parent ptr is %p not %p", |
1126 | node, i, node->kids[i]->parent, node); |
1127 | } |
2d56b16f |
1128 | |
1129 | |
1130 | /* |
1131 | * Now (finally!) recurse into subtrees. |
1132 | */ |
d2371c81 |
1133 | count = nelems; |
1134 | |
2d56b16f |
1135 | for (i = 0; i < nkids; i++) { |
32874aea |
1136 | void *lower = (i == 0 ? lowbound : node->elems[i - 1]); |
1137 | void *higher = (i >= nelems ? highbound : node->elems[i]); |
1138 | int subcount = |
1139 | chknode(ctx, level + 1, node->kids[i], lower, higher); |
d2371c81 |
1140 | if (node->counts[i] != subcount) { |
1141 | error("node %p kid %d: count says %d, subtree really has %d", |
1142 | node, i, node->counts[i], subcount); |
1143 | } |
32874aea |
1144 | count += subcount; |
2d56b16f |
1145 | } |
d2371c81 |
1146 | |
1147 | return count; |
2d56b16f |
1148 | } |
1149 | |
32874aea |
1150 | void verify(void) |
1151 | { |
2d56b16f |
1152 | chkctx ctx; |
2d56b16f |
1153 | int i; |
1154 | void *p; |
1155 | |
32874aea |
1156 | ctx.treedepth = -1; /* depth unknown yet */ |
1157 | ctx.elemcount = 0; /* no elements seen yet */ |
2d56b16f |
1158 | /* |
1159 | * Verify validity of tree properties. |
1160 | */ |
d2371c81 |
1161 | if (tree->root) { |
1162 | if (tree->root->parent != NULL) |
1163 | error("root->parent is %p should be null", tree->root->parent); |
32874aea |
1164 | chknode(&ctx, 0, tree->root, NULL, NULL); |
d2371c81 |
1165 | } |
2d56b16f |
1166 | printf("tree depth: %d\n", ctx.treedepth); |
1167 | /* |
1168 | * Enumerate the tree and ensure it matches up to the array. |
1169 | */ |
d2371c81 |
1170 | for (i = 0; NULL != (p = index234(tree, i)); i++) { |
32874aea |
1171 | if (i >= arraylen) |
1172 | error("tree contains more than %d elements", arraylen); |
1173 | if (array[i] != p) |
1174 | error("enum at position %d: array says %s, tree says %s", |
1175 | i, array[i], p); |
2d56b16f |
1176 | } |
d2371c81 |
1177 | if (ctx.elemcount != i) { |
32874aea |
1178 | error("tree really contains %d elements, enum gave %d", |
1179 | ctx.elemcount, i); |
2d56b16f |
1180 | } |
1181 | if (i < arraylen) { |
32874aea |
1182 | error("enum gave only %d elements, array has %d", i, arraylen); |
2d56b16f |
1183 | } |
d2371c81 |
1184 | i = count234(tree); |
1185 | if (ctx.elemcount != i) { |
32874aea |
1186 | error("tree really contains %d elements, count234 gave %d", |
d2371c81 |
1187 | ctx.elemcount, i); |
1188 | } |
2d56b16f |
1189 | } |
1190 | |
32874aea |
1191 | void internal_addtest(void *elem, int index, void *realret) |
1192 | { |
2d56b16f |
1193 | int i, j; |
d2371c81 |
1194 | void *retval; |
2d56b16f |
1195 | |
32874aea |
1196 | if (arraysize < arraylen + 1) { |
1197 | arraysize = arraylen + 1 + 256; |
3d88e64d |
1198 | array = sresize(array, arraysize, void *); |
2d56b16f |
1199 | } |
1200 | |
d2371c81 |
1201 | i = index; |
2d56b16f |
1202 | /* now i points to the first element >= elem */ |
32874aea |
1203 | retval = elem; /* expect elem returned (success) */ |
d2371c81 |
1204 | for (j = arraylen; j > i; j--) |
32874aea |
1205 | array[j] = array[j - 1]; |
1206 | array[i] = elem; /* add elem to array */ |
d2371c81 |
1207 | arraylen++; |
2d56b16f |
1208 | |
2d56b16f |
1209 | if (realret != retval) { |
32874aea |
1210 | error("add: retval was %p expected %p", realret, retval); |
2d56b16f |
1211 | } |
1212 | |
1213 | verify(); |
1214 | } |
1215 | |
32874aea |
1216 | void addtest(void *elem) |
1217 | { |
2d56b16f |
1218 | int i; |
d2371c81 |
1219 | void *realret; |
1220 | |
1221 | realret = add234(tree, elem); |
2d56b16f |
1222 | |
1223 | i = 0; |
1224 | while (i < arraylen && cmp(elem, array[i]) > 0) |
32874aea |
1225 | i++; |
d2371c81 |
1226 | if (i < arraylen && !cmp(elem, array[i])) { |
32874aea |
1227 | void *retval = array[i]; /* expect that returned not elem */ |
d2371c81 |
1228 | if (realret != retval) { |
1229 | error("add: retval was %p expected %p", realret, retval); |
1230 | } |
1231 | } else |
1232 | internal_addtest(elem, i, realret); |
1233 | } |
1234 | |
32874aea |
1235 | void addpostest(void *elem, int i) |
1236 | { |
d2371c81 |
1237 | void *realret; |
1238 | |
1239 | realret = addpos234(tree, elem, i); |
1240 | |
1241 | internal_addtest(elem, i, realret); |
1242 | } |
1243 | |
32874aea |
1244 | void delpostest(int i) |
1245 | { |
d2371c81 |
1246 | int index = i; |
1247 | void *elem = array[i], *ret; |
1248 | |
1249 | /* i points to the right element */ |
32874aea |
1250 | while (i < arraylen - 1) { |
1251 | array[i] = array[i + 1]; |
d2371c81 |
1252 | i++; |
2d56b16f |
1253 | } |
d2371c81 |
1254 | arraylen--; /* delete elem from array */ |
1255 | |
1256 | if (tree->cmp) |
1257 | ret = del234(tree, elem); |
1258 | else |
1259 | ret = delpos234(tree, index); |
2d56b16f |
1260 | |
d2371c81 |
1261 | if (ret != elem) { |
1262 | error("del returned %p, expected %p", ret, elem); |
1263 | } |
2d56b16f |
1264 | |
1265 | verify(); |
febd9a0f |
1266 | } |
2d56b16f |
1267 | |
32874aea |
1268 | void deltest(void *elem) |
1269 | { |
d2371c81 |
1270 | int i; |
1271 | |
1272 | i = 0; |
1273 | while (i < arraylen && cmp(elem, array[i]) > 0) |
32874aea |
1274 | i++; |
d2371c81 |
1275 | if (i >= arraylen || cmp(elem, array[i]) != 0) |
32874aea |
1276 | return; /* don't do it! */ |
d2371c81 |
1277 | delpostest(i); |
1278 | } |
1279 | |
2d56b16f |
1280 | /* A sample data set and test utility. Designed for pseudo-randomness, |
1281 | * and yet repeatability. */ |
1282 | |
1283 | /* |
1284 | * This random number generator uses the `portable implementation' |
1285 | * given in ANSI C99 draft N869. It assumes `unsigned' is 32 bits; |
1286 | * change it if not. |
1287 | */ |
32874aea |
1288 | int randomnumber(unsigned *seed) |
1289 | { |
2d56b16f |
1290 | *seed *= 1103515245; |
1291 | *seed += 12345; |
1292 | return ((*seed) / 65536) % 32768; |
febd9a0f |
1293 | } |
1294 | |
32874aea |
1295 | int mycmp(void *av, void *bv) |
1296 | { |
1297 | char const *a = (char const *) av; |
1298 | char const *b = (char const *) bv; |
febd9a0f |
1299 | return strcmp(a, b); |
1300 | } |
1301 | |
2d56b16f |
1302 | #define lenof(x) ( sizeof((x)) / sizeof(*(x)) ) |
1303 | |
1304 | char *strings[] = { |
1305 | "a", "ab", "absque", "coram", "de", |
1306 | "palam", "clam", "cum", "ex", "e", |
1307 | "sine", "tenus", "pro", "prae", |
1308 | "banana", "carrot", "cabbage", "broccoli", "onion", "zebra", |
1309 | "penguin", "blancmange", "pangolin", "whale", "hedgehog", |
1310 | "giraffe", "peanut", "bungee", "foo", "bar", "baz", "quux", |
1311 | "murfl", "spoo", "breen", "flarn", "octothorpe", |
1312 | "snail", "tiger", "elephant", "octopus", "warthog", "armadillo", |
1313 | "aardvark", "wyvern", "dragon", "elf", "dwarf", "orc", "goblin", |
1314 | "pixie", "basilisk", "warg", "ape", "lizard", "newt", "shopkeeper", |
1315 | "wand", "ring", "amulet" |
1316 | }; |
1317 | |
1318 | #define NSTR lenof(strings) |
1319 | |
32874aea |
1320 | int findtest(void) |
1321 | { |
d2371c81 |
1322 | const static int rels[] = { |
1323 | REL234_EQ, REL234_GE, REL234_LE, REL234_LT, REL234_GT |
1324 | }; |
1325 | const static char *const relnames[] = { |
1326 | "EQ", "GE", "LE", "LT", "GT" |
1327 | }; |
1328 | int i, j, rel, index; |
1329 | char *p, *ret, *realret, *realret2; |
1330 | int lo, hi, mid, c; |
1331 | |
1332 | for (i = 0; i < NSTR; i++) { |
1333 | p = strings[i]; |
32874aea |
1334 | for (j = 0; j < sizeof(rels) / sizeof(*rels); j++) { |
d2371c81 |
1335 | rel = rels[j]; |
1336 | |
32874aea |
1337 | lo = 0; |
1338 | hi = arraylen - 1; |
d2371c81 |
1339 | while (lo <= hi) { |
1340 | mid = (lo + hi) / 2; |
1341 | c = strcmp(p, array[mid]); |
1342 | if (c < 0) |
32874aea |
1343 | hi = mid - 1; |
d2371c81 |
1344 | else if (c > 0) |
32874aea |
1345 | lo = mid + 1; |
d2371c81 |
1346 | else |
1347 | break; |
1348 | } |
1349 | |
1350 | if (c == 0) { |
1351 | if (rel == REL234_LT) |
1352 | ret = (mid > 0 ? array[--mid] : NULL); |
1353 | else if (rel == REL234_GT) |
32874aea |
1354 | ret = (mid < arraylen - 1 ? array[++mid] : NULL); |
d2371c81 |
1355 | else |
1356 | ret = array[mid]; |
1357 | } else { |
32874aea |
1358 | assert(lo == hi + 1); |
d2371c81 |
1359 | if (rel == REL234_LT || rel == REL234_LE) { |
1360 | mid = hi; |
1361 | ret = (hi >= 0 ? array[hi] : NULL); |
1362 | } else if (rel == REL234_GT || rel == REL234_GE) { |
1363 | mid = lo; |
1364 | ret = (lo < arraylen ? array[lo] : NULL); |
1365 | } else |
1366 | ret = NULL; |
1367 | } |
1368 | |
1369 | realret = findrelpos234(tree, p, NULL, rel, &index); |
1370 | if (realret != ret) { |
1371 | error("find(\"%s\",%s) gave %s should be %s", |
1372 | p, relnames[j], realret, ret); |
1373 | } |
1374 | if (realret && index != mid) { |
1375 | error("find(\"%s\",%s) gave %d should be %d", |
1376 | p, relnames[j], index, mid); |
1377 | } |
1378 | if (realret && rel == REL234_EQ) { |
1379 | realret2 = index234(tree, index); |
1380 | if (realret2 != realret) { |
1381 | error("find(\"%s\",%s) gave %s(%d) but %d -> %s", |
1382 | p, relnames[j], realret, index, index, realret2); |
1383 | } |
1384 | } |
1385 | #if 0 |
1386 | printf("find(\"%s\",%s) gave %s(%d)\n", p, relnames[j], |
1387 | realret, index); |
1388 | #endif |
1389 | } |
1390 | } |
1391 | |
1392 | realret = findrelpos234(tree, NULL, NULL, REL234_GT, &index); |
1393 | if (arraylen && (realret != array[0] || index != 0)) { |
1394 | error("find(NULL,GT) gave %s(%d) should be %s(0)", |
1395 | realret, index, array[0]); |
1396 | } else if (!arraylen && (realret != NULL)) { |
32874aea |
1397 | error("find(NULL,GT) gave %s(%d) should be NULL", realret, index); |
d2371c81 |
1398 | } |
1399 | |
1400 | realret = findrelpos234(tree, NULL, NULL, REL234_LT, &index); |
32874aea |
1401 | if (arraylen |
1402 | && (realret != array[arraylen - 1] || index != arraylen - 1)) { |
1403 | error("find(NULL,LT) gave %s(%d) should be %s(0)", realret, index, |
1404 | array[arraylen - 1]); |
d2371c81 |
1405 | } else if (!arraylen && (realret != NULL)) { |
32874aea |
1406 | error("find(NULL,LT) gave %s(%d) should be NULL", realret, index); |
d2371c81 |
1407 | } |
1408 | } |
1409 | |
32874aea |
1410 | int main(void) |
1411 | { |
2d56b16f |
1412 | int in[NSTR]; |
d2371c81 |
1413 | int i, j, k; |
2d56b16f |
1414 | unsigned seed = 0; |
1415 | |
32874aea |
1416 | for (i = 0; i < NSTR; i++) |
1417 | in[i] = 0; |
2d56b16f |
1418 | array = NULL; |
1419 | arraylen = arraysize = 0; |
1420 | tree = newtree234(mycmp); |
1421 | cmp = mycmp; |
1422 | |
1423 | verify(); |
1424 | for (i = 0; i < 10000; i++) { |
32874aea |
1425 | j = randomnumber(&seed); |
1426 | j %= NSTR; |
1427 | printf("trial: %d\n", i); |
1428 | if (in[j]) { |
1429 | printf("deleting %s (%d)\n", strings[j], j); |
1430 | deltest(strings[j]); |
1431 | in[j] = 0; |
1432 | } else { |
1433 | printf("adding %s (%d)\n", strings[j], j); |
1434 | addtest(strings[j]); |
1435 | in[j] = 1; |
1436 | } |
d2371c81 |
1437 | findtest(); |
2d56b16f |
1438 | } |
1439 | |
1440 | while (arraylen > 0) { |
32874aea |
1441 | j = randomnumber(&seed); |
1442 | j %= arraylen; |
1443 | deltest(array[j]); |
2d56b16f |
1444 | } |
1445 | |
d2371c81 |
1446 | freetree234(tree); |
1447 | |
1448 | /* |
1449 | * Now try an unsorted tree. We don't really need to test |
1450 | * delpos234 because we know del234 is based on it, so it's |
1451 | * already been tested in the above sorted-tree code; but for |
1452 | * completeness we'll use it to tear down our unsorted tree |
1453 | * once we've built it. |
1454 | */ |
1455 | tree = newtree234(NULL); |
1456 | cmp = NULL; |
1457 | verify(); |
1458 | for (i = 0; i < 1000; i++) { |
1459 | printf("trial: %d\n", i); |
1460 | j = randomnumber(&seed); |
1461 | j %= NSTR; |
1462 | k = randomnumber(&seed); |
32874aea |
1463 | k %= count234(tree) + 1; |
d2371c81 |
1464 | printf("adding string %s at index %d\n", strings[j], k); |
1465 | addpostest(strings[j], k); |
1466 | } |
1467 | while (count234(tree) > 0) { |
1468 | printf("cleanup: tree size %d\n", count234(tree)); |
1469 | j = randomnumber(&seed); |
1470 | j %= count234(tree); |
1471 | printf("deleting string %s from index %d\n", array[j], j); |
1472 | delpostest(j); |
1473 | } |
1474 | |
2d56b16f |
1475 | return 0; |
febd9a0f |
1476 | } |
2d56b16f |
1477 | |
febd9a0f |
1478 | #endif |