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6973fc01 | 1 | /* Provide access to the collection of available transformation modules. |
8a0746ae | 2 | Copyright (C) 1997,98,99,2000,2001 Free Software Foundation, Inc. |
6973fc01 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Library General Public License as | |
8 | published by the Free Software Foundation; either version 2 of the | |
9 | License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Library General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Library General Public | |
17 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
18 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
2bd60880 | 21 | #include <limits.h> |
6973fc01 UD |
22 | #include <search.h> |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
2bd60880 | 25 | #include <sys/param.h> |
6973fc01 | 26 | #include <bits/libc-lock.h> |
816e6eb5 | 27 | |
b3fc5f84 | 28 | #include <dlfcn.h> |
e62c19f1 UD |
29 | #include <gconv_int.h> |
30 | ||
6973fc01 UD |
31 | |
32 | /* Simple data structure for alias mapping. We have two names, `from' | |
33 | and `to'. */ | |
34 | void *__gconv_alias_db; | |
35 | ||
36 | /* Array with available modules. */ | |
2bd60880 | 37 | struct gconv_module *__gconv_modules_db; |
6973fc01 | 38 | |
0d9f6793 UD |
39 | /* We modify global data. */ |
40 | __libc_lock_define_initialized (static, lock) | |
41 | ||
6973fc01 UD |
42 | |
43 | /* Function for searching alias. */ | |
44 | int | |
45 | __gconv_alias_compare (const void *p1, const void *p2) | |
46 | { | |
17427edd UD |
47 | const struct gconv_alias *s1 = (const struct gconv_alias *) p1; |
48 | const struct gconv_alias *s2 = (const struct gconv_alias *) p2; | |
bd4848fb | 49 | return strcmp (s1->fromname, s2->fromname); |
6973fc01 UD |
50 | } |
51 | ||
52 | ||
53 | /* To search for a derivation we create a list of intermediate steps. | |
54 | Each element contains a pointer to the element which precedes it | |
55 | in the derivation order. */ | |
56 | struct derivation_step | |
57 | { | |
58 | const char *result_set; | |
2bd60880 UD |
59 | size_t result_set_len; |
60 | int cost_lo; | |
61 | int cost_hi; | |
6973fc01 UD |
62 | struct gconv_module *code; |
63 | struct derivation_step *last; | |
64 | struct derivation_step *next; | |
65 | }; | |
66 | ||
2bd60880 | 67 | #define NEW_STEP(result, hi, lo, module, last_mod) \ |
6973fc01 UD |
68 | ({ struct derivation_step *newp = alloca (sizeof (struct derivation_step)); \ |
69 | newp->result_set = result; \ | |
2bd60880 UD |
70 | newp->result_set_len = strlen (result); \ |
71 | newp->cost_hi = hi; \ | |
72 | newp->cost_lo = lo; \ | |
6973fc01 UD |
73 | newp->code = module; \ |
74 | newp->last = last_mod; \ | |
75 | newp->next = NULL; \ | |
76 | newp; }) | |
77 | ||
78 | ||
79 | /* If a specific transformation is used more than once we should not need | |
80 | to start looking for it again. Instead cache each successful result. */ | |
81 | struct known_derivation | |
82 | { | |
83 | const char *from; | |
84 | const char *to; | |
d64b6ad0 | 85 | struct __gconv_step *steps; |
6973fc01 UD |
86 | size_t nsteps; |
87 | }; | |
88 | ||
89 | /* Compare function for database of found derivations. */ | |
90 | static int | |
91 | derivation_compare (const void *p1, const void *p2) | |
92 | { | |
17427edd UD |
93 | const struct known_derivation *s1 = (const struct known_derivation *) p1; |
94 | const struct known_derivation *s2 = (const struct known_derivation *) p2; | |
6973fc01 UD |
95 | int result; |
96 | ||
97 | result = strcmp (s1->from, s2->from); | |
98 | if (result == 0) | |
99 | result = strcmp (s1->to, s2->to); | |
100 | return result; | |
101 | } | |
102 | ||
103 | /* The search tree for known derivations. */ | |
104 | static void *known_derivations; | |
105 | ||
106 | /* Look up whether given transformation was already requested before. */ | |
107 | static int | |
e62c19f1 | 108 | internal_function |
6973fc01 | 109 | derivation_lookup (const char *fromset, const char *toset, |
d64b6ad0 | 110 | struct __gconv_step **handle, size_t *nsteps) |
6973fc01 UD |
111 | { |
112 | struct known_derivation key = { fromset, toset, NULL, 0 }; | |
bd687f7a | 113 | struct known_derivation **result; |
6973fc01 | 114 | |
e34b0f29 | 115 | result = __tfind (&key, &known_derivations, derivation_compare); |
6973fc01 UD |
116 | |
117 | if (result == NULL) | |
d64b6ad0 | 118 | return __GCONV_NOCONV; |
6973fc01 | 119 | |
bd687f7a UD |
120 | *handle = (*result)->steps; |
121 | *nsteps = (*result)->nsteps; | |
6973fc01 UD |
122 | |
123 | /* Please note that we return GCONV_OK even if the last search for | |
124 | this transformation was unsuccessful. */ | |
d64b6ad0 | 125 | return __GCONV_OK; |
6973fc01 UD |
126 | } |
127 | ||
128 | /* Add new derivation to list of known ones. */ | |
129 | static void | |
e62c19f1 | 130 | internal_function |
6973fc01 | 131 | add_derivation (const char *fromset, const char *toset, |
d64b6ad0 | 132 | struct __gconv_step *handle, size_t nsteps) |
6973fc01 UD |
133 | { |
134 | struct known_derivation *new_deriv; | |
135 | size_t fromset_len = strlen (fromset) + 1; | |
136 | size_t toset_len = strlen (toset) + 1; | |
137 | ||
138 | new_deriv = (struct known_derivation *) | |
139 | malloc (sizeof (struct known_derivation) + fromset_len + toset_len); | |
140 | if (new_deriv != NULL) | |
141 | { | |
390500b1 UD |
142 | new_deriv->from = (char *) (new_deriv + 1); |
143 | new_deriv->to = memcpy (__mempcpy (new_deriv + 1, fromset, fromset_len), | |
6973fc01 UD |
144 | toset, toset_len); |
145 | ||
146 | new_deriv->steps = handle; | |
147 | new_deriv->nsteps = nsteps; | |
148 | ||
390500b1 UD |
149 | if (__tsearch (new_deriv, &known_derivations, derivation_compare) |
150 | == NULL) | |
151 | /* There is some kind of memory allocation problem. */ | |
152 | free (new_deriv); | |
6973fc01 UD |
153 | } |
154 | /* Please note that we don't complain if the allocation failed. This | |
155 | is not tragically but in case we use the memory debugging facilities | |
156 | not all memory will be freed. */ | |
157 | } | |
158 | ||
159 | static void | |
160 | free_derivation (void *p) | |
161 | { | |
162 | struct known_derivation *deriv = (struct known_derivation *) p; | |
0d9f6793 UD |
163 | size_t cnt; |
164 | ||
165 | for (cnt = 0; cnt < deriv->nsteps; ++cnt) | |
b79f74cd UD |
166 | if (deriv->steps[cnt].__counter > 0 |
167 | && deriv->steps[cnt].__end_fct != NULL) | |
94e365c6 | 168 | DL_CALL_FCT (deriv->steps[cnt].__end_fct, (&deriv->steps[cnt])); |
6973fc01 | 169 | |
74454183 | 170 | /* Free the name strings. */ |
d64b6ad0 UD |
171 | free ((char *) deriv->steps[0].__from_name); |
172 | free ((char *) deriv->steps[deriv->nsteps - 1].__to_name); | |
74454183 | 173 | |
d64b6ad0 | 174 | free ((struct __gconv_step *) deriv->steps); |
6973fc01 UD |
175 | free (deriv); |
176 | } | |
177 | ||
178 | ||
b79f74cd UD |
179 | /* Decrement the reference count for a single step in a steps array. */ |
180 | static inline void | |
181 | release_step (struct __gconv_step *step) | |
182 | { | |
183 | if (--step->__counter == 0) | |
184 | { | |
185 | /* Call the destructor. */ | |
186 | if (step->__end_fct != NULL) | |
187 | DL_CALL_FCT (step->__end_fct, (step)); | |
188 | ||
189 | #ifndef STATIC_GCONV | |
190 | /* Skip builtin modules; they are not reference counted. */ | |
191 | if (step->__shlib_handle != NULL) | |
192 | { | |
193 | /* Release the loaded module. */ | |
194 | __gconv_release_shlib (step->__shlib_handle); | |
195 | step->__shlib_handle = NULL; | |
196 | } | |
197 | #endif | |
198 | } | |
199 | } | |
200 | ||
6973fc01 UD |
201 | static int |
202 | internal_function | |
203 | gen_steps (struct derivation_step *best, const char *toset, | |
d64b6ad0 | 204 | const char *fromset, struct __gconv_step **handle, size_t *nsteps) |
6973fc01 UD |
205 | { |
206 | size_t step_cnt = 0; | |
d64b6ad0 | 207 | struct __gconv_step *result; |
6973fc01 | 208 | struct derivation_step *current; |
d64b6ad0 | 209 | int status = __GCONV_NOMEM; |
6973fc01 UD |
210 | |
211 | /* First determine number of steps. */ | |
212 | for (current = best; current->last != NULL; current = current->last) | |
213 | ++step_cnt; | |
214 | ||
d64b6ad0 UD |
215 | result = (struct __gconv_step *) malloc (sizeof (struct __gconv_step) |
216 | * step_cnt); | |
6973fc01 UD |
217 | if (result != NULL) |
218 | { | |
e34b0f29 UD |
219 | int failed = 0; |
220 | ||
d64b6ad0 | 221 | status = __GCONV_OK; |
e34b0f29 | 222 | *nsteps = step_cnt; |
6973fc01 UD |
223 | current = best; |
224 | while (step_cnt-- > 0) | |
225 | { | |
d64b6ad0 UD |
226 | result[step_cnt].__from_name = (step_cnt == 0 |
227 | ? __strdup (fromset) | |
8a0746ae | 228 | : (char *)current->last->result_set); |
d64b6ad0 UD |
229 | result[step_cnt].__to_name = (step_cnt + 1 == *nsteps |
230 | ? __strdup (current->result_set) | |
231 | : result[step_cnt + 1].__from_name); | |
6973fc01 | 232 | |
8619129f | 233 | #ifndef STATIC_GCONV |
6973fc01 UD |
234 | if (current->code->module_name[0] == '/') |
235 | { | |
236 | /* Load the module, return handle for it. */ | |
d64b6ad0 | 237 | struct __gconv_loaded_object *shlib_handle = |
6973fc01 UD |
238 | __gconv_find_shlib (current->code->module_name); |
239 | ||
240 | if (shlib_handle == NULL) | |
e34b0f29 UD |
241 | { |
242 | failed = 1; | |
243 | break; | |
244 | } | |
6973fc01 | 245 | |
d64b6ad0 UD |
246 | result[step_cnt].__shlib_handle = shlib_handle; |
247 | result[step_cnt].__modname = shlib_handle->name; | |
d64b6ad0 UD |
248 | result[step_cnt].__fct = shlib_handle->fct; |
249 | result[step_cnt].__init_fct = shlib_handle->init_fct; | |
250 | result[step_cnt].__end_fct = shlib_handle->end_fct; | |
6973fc01 UD |
251 | } |
252 | else | |
8619129f | 253 | #endif |
6973fc01 UD |
254 | /* It's a builtin transformation. */ |
255 | __gconv_get_builtin_trans (current->code->module_name, | |
256 | &result[step_cnt]); | |
257 | ||
b79f74cd UD |
258 | result[step_cnt].__counter = 1; |
259 | ||
0d9f6793 | 260 | /* Call the init function. */ |
405b8c60 | 261 | result[step_cnt].__data = NULL; |
d64b6ad0 | 262 | if (result[step_cnt].__init_fct != NULL) |
c7ec9d75 | 263 | { |
94e365c6 | 264 | status = DL_CALL_FCT (result[step_cnt].__init_fct, |
c7ec9d75 | 265 | (&result[step_cnt])); |
2bd60880 | 266 | |
5ea1a82d | 267 | if (__builtin_expect (status, __GCONV_OK) != __GCONV_OK) |
c7ec9d75 UD |
268 | { |
269 | failed = 1; | |
270 | /* Make sure we unload this modules. */ | |
271 | --step_cnt; | |
b79f74cd | 272 | result[step_cnt].__end_fct = NULL; |
c7ec9d75 UD |
273 | break; |
274 | } | |
275 | } | |
0d9f6793 | 276 | |
6973fc01 UD |
277 | current = current->last; |
278 | } | |
279 | ||
5ea1a82d | 280 | if (__builtin_expect (failed, 0) != 0) |
6973fc01 UD |
281 | { |
282 | /* Something went wrong while initializing the modules. */ | |
e34b0f29 | 283 | while (++step_cnt < *nsteps) |
b79f74cd | 284 | release_step (&result[step_cnt]); |
6973fc01 | 285 | free (result); |
e34b0f29 | 286 | *nsteps = 0; |
7a68c94a | 287 | *handle = NULL; |
d64b6ad0 UD |
288 | if (status == __GCONV_OK) |
289 | status = __GCONV_NOCONV; | |
6973fc01 UD |
290 | } |
291 | else | |
c7ec9d75 | 292 | *handle = result; |
6973fc01 | 293 | } |
7a68c94a UD |
294 | else |
295 | { | |
296 | *nsteps = 0; | |
297 | *handle = NULL; | |
298 | } | |
6973fc01 UD |
299 | |
300 | return status; | |
301 | } | |
302 | ||
303 | ||
76a2102b UD |
304 | #ifndef STATIC_GCONV |
305 | static int | |
306 | internal_function | |
307 | increment_counter (struct __gconv_step *steps, size_t nsteps) | |
308 | { | |
309 | /* Increment the user counter. */ | |
310 | size_t cnt = nsteps; | |
311 | int result = __GCONV_OK; | |
312 | ||
313 | while (cnt-- > 0) | |
b79f74cd UD |
314 | { |
315 | struct __gconv_step *step = &steps[cnt]; | |
316 | ||
317 | if (step->__counter++ == 0) | |
318 | { | |
319 | /* Skip builtin modules. */ | |
320 | if (step->__modname != NULL) | |
321 | { | |
322 | /* Reopen a previously used module. */ | |
323 | step->__shlib_handle = __gconv_find_shlib (step->__modname); | |
324 | if (step->__shlib_handle == NULL) | |
325 | { | |
326 | /* Oops, this is the second time we use this module | |
327 | (after unloading) and this time loading failed!? */ | |
328 | --step->__counter; | |
329 | while (++cnt < nsteps) | |
330 | release_step (&steps[cnt]); | |
331 | result = __GCONV_NOCONV; | |
332 | break; | |
333 | } | |
334 | ||
335 | /* The function addresses defined by the module may | |
336 | have changed. */ | |
337 | step->__fct = step->__shlib_handle->fct; | |
338 | step->__init_fct = step->__shlib_handle->init_fct; | |
339 | step->__end_fct = step->__shlib_handle->end_fct; | |
340 | } | |
341 | ||
342 | if (step->__init_fct != NULL) | |
343 | DL_CALL_FCT (step->__init_fct, (step)); | |
344 | } | |
345 | } | |
76a2102b UD |
346 | return result; |
347 | } | |
348 | #endif | |
349 | ||
350 | ||
6973fc01 UD |
351 | /* The main function: find a possible derivation from the `fromset' (either |
352 | the given name or the alias) to the `toset' (again with alias). */ | |
353 | static int | |
e34b0f29 | 354 | internal_function |
6973fc01 UD |
355 | find_derivation (const char *toset, const char *toset_expand, |
356 | const char *fromset, const char *fromset_expand, | |
d64b6ad0 | 357 | struct __gconv_step **handle, size_t *nsteps) |
6973fc01 | 358 | { |
2bd60880 UD |
359 | struct derivation_step *first, *current, **lastp, *solution = NULL; |
360 | int best_cost_hi = INT_MAX; | |
361 | int best_cost_lo = INT_MAX; | |
6973fc01 UD |
362 | int result; |
363 | ||
b79f74cd UD |
364 | /* Look whether an earlier call to `find_derivation' has already |
365 | computed a possible derivation. If so, return it immediately. */ | |
6973fc01 UD |
366 | result = derivation_lookup (fromset_expand ?: fromset, toset_expand ?: toset, |
367 | handle, nsteps); | |
d64b6ad0 | 368 | if (result == __GCONV_OK) |
3c5edd4d | 369 | { |
76a2102b UD |
370 | #ifndef STATIC_GCONV |
371 | result = increment_counter (*handle, *nsteps); | |
372 | #endif | |
3c5edd4d UD |
373 | return result; |
374 | } | |
6973fc01 | 375 | |
b79f74cd UD |
376 | /* The task is to find a sequence of transformations, backed by the |
377 | existing modules - whether builtin or dynamically loadable -, | |
378 | starting at `fromset' (or `fromset_expand') and ending at `toset' | |
379 | (or `toset_expand'), and with minimal cost. | |
380 | ||
381 | For computer scientists, this is a shortest path search in the | |
382 | graph where the nodes are all possible charsets and the edges are | |
383 | the transformations listed in __gconv_modules_db. | |
384 | ||
385 | For now we use a simple algorithm with quadratic runtime behaviour. | |
386 | A breadth-first search, starting at `fromset' and `fromset_expand'. | |
387 | The list starting at `first' contains all nodes that have been | |
388 | visited up to now, in the order in which they have been visited -- | |
389 | excluding the goal nodes `toset' and `toset_expand' which get | |
390 | managed in the list starting at `solution'. | |
391 | `current' walks through the list starting at `first' and looks | |
392 | which nodes are reachable from the current node, adding them to | |
393 | the end of the list [`first' or `solution' respectively] (if | |
394 | they are visited the first time) or updating them in place (if | |
395 | they have have already been visited). | |
396 | In each node of either list, cost_lo and cost_hi contain the | |
397 | minimum cost over any paths found up to now, starting at `fromset' | |
398 | or `fromset_expand', ending at that node. best_cost_lo and | |
399 | best_cost_hi represent the minimum over the elements of the | |
400 | `solution' list. */ | |
401 | ||
6973fc01 UD |
402 | if (fromset_expand != NULL) |
403 | { | |
2bd60880 UD |
404 | first = NEW_STEP (fromset_expand, 0, 0, NULL, NULL); |
405 | first->next = NEW_STEP (fromset, 0, 0, NULL, NULL); | |
e34b0f29 | 406 | lastp = &first->next->next; |
6973fc01 UD |
407 | } |
408 | else | |
409 | { | |
2bd60880 | 410 | first = NEW_STEP (fromset, 0, 0, NULL, NULL); |
e34b0f29 | 411 | lastp = &first->next; |
6973fc01 UD |
412 | } |
413 | ||
2bd60880 | 414 | for (current = first; current != NULL; current = current->next) |
6973fc01 UD |
415 | { |
416 | /* Now match all the available module specifications against the | |
417 | current charset name. If any of them matches check whether | |
418 | we already have a derivation for this charset. If yes, use the | |
419 | one with the lower costs. Otherwise add the new charset at the | |
2bd60880 UD |
420 | end. |
421 | ||
e8b1163e AJ |
422 | The module database is organized in a tree form which allows |
423 | searching for prefixes. So we search for the first entry with a | |
2bd60880 UD |
424 | matching prefix and any other matching entry can be found from |
425 | this place. */ | |
b79f74cd | 426 | struct gconv_module *node; |
2bd60880 UD |
427 | |
428 | /* Maybe it is not necessary anymore to look for a solution for | |
b79f74cd | 429 | this entry since the cost is already as high (or higher) as |
2bd60880 UD |
430 | the cost for the best solution so far. */ |
431 | if (current->cost_hi > best_cost_hi | |
432 | || (current->cost_hi == best_cost_hi | |
433 | && current->cost_lo >= best_cost_lo)) | |
434 | continue; | |
435 | ||
b79f74cd | 436 | node = __gconv_modules_db; |
2bd60880 UD |
437 | while (node != NULL) |
438 | { | |
d2dfc5de | 439 | int cmpres = strcmp (current->result_set, node->from_string); |
2bd60880 | 440 | if (cmpres == 0) |
6973fc01 | 441 | { |
2bd60880 UD |
442 | /* Walk through the list of modules with this prefix and |
443 | try to match the name. */ | |
444 | struct gconv_module *runp; | |
445 | ||
2bd60880 UD |
446 | /* Check all the modules with this prefix. */ |
447 | runp = node; | |
448 | do | |
6973fc01 | 449 | { |
d2dfc5de UD |
450 | const char *result_set = (strcmp (runp->to_string, "-") == 0 |
451 | ? (toset_expand ?: toset) | |
452 | : runp->to_string); | |
453 | int cost_hi = runp->cost_hi + current->cost_hi; | |
454 | int cost_lo = runp->cost_lo + current->cost_lo; | |
455 | struct derivation_step *step; | |
456 | ||
457 | /* We managed to find a derivation. First see whether | |
b79f74cd | 458 | we have reached one of the goal nodes. */ |
d2dfc5de UD |
459 | if (strcmp (result_set, toset) == 0 |
460 | || (toset_expand != NULL | |
461 | && strcmp (result_set, toset_expand) == 0)) | |
2bd60880 | 462 | { |
b79f74cd UD |
463 | /* Append to the `solution' list if there |
464 | is no entry with this name. */ | |
465 | for (step = solution; step != NULL; step = step->next) | |
466 | if (strcmp (result_set, step->result_set) == 0) | |
467 | break; | |
468 | ||
469 | if (step == NULL) | |
470 | { | |
471 | step = NEW_STEP (result_set, | |
472 | cost_hi, cost_lo, | |
473 | runp, current); | |
474 | step->next = solution; | |
475 | solution = step; | |
476 | } | |
477 | else if (step->cost_hi > cost_hi | |
478 | || (step->cost_hi == cost_hi | |
479 | && step->cost_lo > cost_lo)) | |
480 | { | |
481 | /* A better path was found for the node, | |
482 | on the `solution' list. */ | |
483 | step->code = runp; | |
484 | step->last = current; | |
485 | step->cost_hi = cost_hi; | |
486 | step->cost_lo = cost_lo; | |
487 | } | |
488 | ||
489 | /* Update best_cost accordingly. */ | |
490 | if (cost_hi < best_cost_hi | |
d2dfc5de UD |
491 | || (cost_hi == best_cost_hi |
492 | && cost_lo < best_cost_lo)) | |
2bd60880 | 493 | { |
d2dfc5de UD |
494 | best_cost_hi = cost_hi; |
495 | best_cost_lo = cost_lo; | |
2bd60880 | 496 | } |
6973fc01 | 497 | } |
d2dfc5de UD |
498 | else if (cost_hi < best_cost_hi |
499 | || (cost_hi == best_cost_hi | |
500 | && cost_lo < best_cost_lo)) | |
6973fc01 | 501 | { |
b79f74cd UD |
502 | /* Append at the end of the `first' list if there |
503 | is no entry with this name. */ | |
d2dfc5de UD |
504 | for (step = first; step != NULL; step = step->next) |
505 | if (strcmp (result_set, step->result_set) == 0) | |
506 | break; | |
2bd60880 | 507 | |
d2dfc5de UD |
508 | if (step == NULL) |
509 | { | |
510 | *lastp = NEW_STEP (result_set, | |
511 | cost_hi, cost_lo, | |
512 | runp, current); | |
513 | lastp = &(*lastp)->next; | |
2bd60880 | 514 | } |
d2dfc5de UD |
515 | else if (step->cost_hi > cost_hi |
516 | || (step->cost_hi == cost_hi | |
517 | && step->cost_lo > cost_lo)) | |
2bd60880 | 518 | { |
b79f74cd UD |
519 | /* A better path was found for the node, |
520 | on the `first' list. */ | |
d2dfc5de UD |
521 | step->code = runp; |
522 | step->last = current; | |
2bd60880 | 523 | |
d2dfc5de UD |
524 | /* Update the cost for all steps. */ |
525 | for (step = first; step != NULL; | |
526 | step = step->next) | |
b79f74cd UD |
527 | /* But don't update the start nodes. */ |
528 | if (step->code != NULL) | |
529 | { | |
530 | struct derivation_step *back; | |
531 | int hi, lo; | |
532 | ||
533 | hi = step->code->cost_hi; | |
534 | lo = step->code->cost_lo; | |
535 | ||
536 | for (back = step->last; back->code != NULL; | |
537 | back = back->last) | |
538 | { | |
539 | hi += back->code->cost_hi; | |
540 | lo += back->code->cost_lo; | |
541 | } | |
542 | ||
543 | step->cost_hi = hi; | |
544 | step->cost_lo = lo; | |
545 | } | |
546 | ||
547 | /* Likewise for the nodes on the solution list. | |
548 | Also update best_cost accordingly. */ | |
d2dfc5de UD |
549 | for (step = solution; step != NULL; |
550 | step = step->next) | |
551 | { | |
552 | step->cost_hi = (step->code->cost_hi | |
553 | + step->last->cost_hi); | |
554 | step->cost_lo = (step->code->cost_lo | |
555 | + step->last->cost_lo); | |
556 | ||
557 | if (step->cost_hi < best_cost_hi | |
558 | || (step->cost_hi == best_cost_hi | |
559 | && step->cost_lo < best_cost_lo)) | |
2bd60880 | 560 | { |
d2dfc5de UD |
561 | best_cost_hi = step->cost_hi; |
562 | best_cost_lo = step->cost_lo; | |
2bd60880 UD |
563 | } |
564 | } | |
565 | } | |
6973fc01 | 566 | } |
2bd60880 UD |
567 | |
568 | runp = runp->same; | |
6973fc01 | 569 | } |
2bd60880 | 570 | while (runp != NULL); |
e34b0f29 | 571 | |
d2dfc5de | 572 | break; |
6973fc01 | 573 | } |
2bd60880 UD |
574 | else if (cmpres < 0) |
575 | node = node->left; | |
576 | else | |
577 | node = node->right; | |
6973fc01 UD |
578 | } |
579 | } | |
580 | ||
2bd60880 | 581 | if (solution != NULL) |
b79f74cd UD |
582 | { |
583 | /* We really found a way to do the transformation. */ | |
584 | ||
585 | /* Choose the best solution. This is easy because we know that | |
586 | the solution list has at most length 2 (one for every possible | |
587 | goal node). */ | |
588 | if (solution->next != NULL) | |
589 | { | |
590 | struct derivation_step *solution2 = solution->next; | |
591 | ||
592 | if (solution2->cost_hi < solution->cost_hi | |
593 | || (solution2->cost_hi == solution->cost_hi | |
594 | && solution2->cost_lo < solution->cost_lo)) | |
595 | solution = solution2; | |
596 | } | |
597 | ||
598 | /* Now build a data structure describing the transformation steps. */ | |
599 | result = gen_steps (solution, toset_expand ?: toset, | |
600 | fromset_expand ?: fromset, handle, nsteps); | |
601 | } | |
6973fc01 UD |
602 | else |
603 | { | |
604 | /* We haven't found a transformation. Clear the result values. */ | |
605 | *handle = NULL; | |
606 | *nsteps = 0; | |
607 | } | |
608 | ||
609 | /* Add result in any case to list of known derivations. */ | |
610 | add_derivation (fromset_expand ?: fromset, toset_expand ?: toset, | |
611 | *handle, *nsteps); | |
612 | ||
6973fc01 UD |
613 | return result; |
614 | } | |
615 | ||
616 | ||
617 | int | |
e62c19f1 | 618 | internal_function |
6973fc01 | 619 | __gconv_find_transform (const char *toset, const char *fromset, |
60c53a12 UD |
620 | struct __gconv_step **handle, size_t *nsteps, |
621 | int flags) | |
6973fc01 UD |
622 | { |
623 | __libc_once_define (static, once); | |
624 | const char *fromset_expand = NULL; | |
625 | const char *toset_expand = NULL; | |
626 | int result; | |
627 | ||
628 | /* Ensure that the configuration data is read. */ | |
629 | __libc_once (once, __gconv_read_conf); | |
630 | ||
0d9f6793 UD |
631 | /* Acquire the lock. */ |
632 | __libc_lock_lock (lock); | |
633 | ||
6973fc01 UD |
634 | /* If we don't have a module database return with an error. */ |
635 | if (__gconv_modules_db == NULL) | |
3c5edd4d UD |
636 | { |
637 | __libc_lock_unlock (lock); | |
d64b6ad0 | 638 | return __GCONV_NOCONV; |
3c5edd4d | 639 | } |
6973fc01 UD |
640 | |
641 | /* See whether the names are aliases. */ | |
642 | if (__gconv_alias_db != NULL) | |
643 | { | |
644 | struct gconv_alias key; | |
e34b0f29 | 645 | struct gconv_alias **found; |
6973fc01 | 646 | |
8a0746ae | 647 | key.fromname = (char *) fromset; |
e34b0f29 UD |
648 | found = __tfind (&key, &__gconv_alias_db, __gconv_alias_compare); |
649 | fromset_expand = found != NULL ? (*found)->toname : NULL; | |
6973fc01 | 650 | |
8a0746ae | 651 | key.fromname = (char *) toset; |
e34b0f29 UD |
652 | found = __tfind (&key, &__gconv_alias_db, __gconv_alias_compare); |
653 | toset_expand = found != NULL ? (*found)->toname : NULL; | |
6973fc01 UD |
654 | } |
655 | ||
5ea1a82d | 656 | if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0) |
60c53a12 UD |
657 | /* We are not supposed to create a pseudo transformation (means |
658 | copying) when the input and output character set are the same. */ | |
659 | && (strcmp (toset, fromset) == 0 | |
660 | || (toset_expand != NULL && strcmp (toset_expand, fromset) == 0) | |
661 | || (fromset_expand != NULL | |
662 | && (strcmp (toset, fromset_expand) == 0 | |
663 | || (toset_expand != NULL | |
664 | && strcmp (toset_expand, fromset_expand) == 0))))) | |
665 | { | |
666 | /* Both character sets are the same. */ | |
667 | __libc_lock_unlock (lock); | |
668 | return __GCONV_NOCONV; | |
669 | } | |
670 | ||
6973fc01 UD |
671 | result = find_derivation (toset, toset_expand, fromset, fromset_expand, |
672 | handle, nsteps); | |
673 | ||
0d9f6793 UD |
674 | /* Release the lock. */ |
675 | __libc_lock_unlock (lock); | |
676 | ||
6973fc01 UD |
677 | /* The following code is necessary since `find_derivation' will return |
678 | GCONV_OK even when no derivation was found but the same request | |
679 | was processed before. I.e., negative results will also be cached. */ | |
d64b6ad0 UD |
680 | return (result == __GCONV_OK |
681 | ? (*handle == NULL ? __GCONV_NOCONV : __GCONV_OK) | |
6973fc01 UD |
682 | : result); |
683 | } | |
684 | ||
685 | ||
686 | /* Release the entries of the modules list. */ | |
687 | int | |
e62c19f1 | 688 | internal_function |
d64b6ad0 | 689 | __gconv_close_transform (struct __gconv_step *steps, size_t nsteps) |
6973fc01 | 690 | { |
d64b6ad0 | 691 | int result = __GCONV_OK; |
6973fc01 | 692 | |
8619129f | 693 | #ifndef STATIC_GCONV |
0d9f6793 UD |
694 | /* Acquire the lock. */ |
695 | __libc_lock_lock (lock); | |
696 | ||
6973fc01 | 697 | while (nsteps-- > 0) |
b79f74cd | 698 | release_step (&steps[nsteps]); |
6973fc01 | 699 | |
0d9f6793 UD |
700 | /* Release the lock. */ |
701 | __libc_lock_unlock (lock); | |
8619129f | 702 | #endif |
0d9f6793 | 703 | |
6973fc01 UD |
704 | return result; |
705 | } | |
706 | ||
707 | ||
2bd60880 UD |
708 | /* Free the modules mentioned. */ |
709 | static void | |
710 | internal_function | |
711 | free_modules_db (struct gconv_module *node) | |
712 | { | |
713 | if (node->left != NULL) | |
714 | free_modules_db (node->left); | |
715 | if (node->right != NULL) | |
716 | free_modules_db (node->right); | |
2bd60880 UD |
717 | do |
718 | { | |
719 | struct gconv_module *act = node; | |
d2dfc5de | 720 | node = node->same; |
8ce63ec0 UD |
721 | if (act->module_name[0] == '/') |
722 | free (act); | |
2bd60880 UD |
723 | } |
724 | while (node != NULL); | |
725 | } | |
726 | ||
727 | ||
6973fc01 UD |
728 | /* Free all resources if necessary. */ |
729 | static void __attribute__ ((unused)) | |
730 | free_mem (void) | |
731 | { | |
6973fc01 UD |
732 | if (__gconv_alias_db != NULL) |
733 | __tdestroy (__gconv_alias_db, free); | |
734 | ||
0dbbad29 UD |
735 | if (__gconv_modules_db != NULL) |
736 | free_modules_db (__gconv_modules_db); | |
6973fc01 UD |
737 | |
738 | if (known_derivations != NULL) | |
739 | __tdestroy (known_derivations, free_derivation); | |
740 | } | |
741 | ||
742 | text_set_element (__libc_subfreeres, free_mem); |