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6b98979f | 1 | /* C string table handling. |
d614a753 | 2 | Copyright (C) 2000-2020 Free Software Foundation, Inc. |
6b98979f UD |
3 | Written by Ulrich Drepper <drepper@redhat.com>, 2000. |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 2, or (at your option) | |
8 | any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
5a82c748 | 16 | along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
6b98979f UD |
17 | |
18 | #ifdef HAVE_CONFIG_H | |
19 | # include <config.h> | |
20 | #endif | |
21 | ||
22 | #include <assert.h> | |
23 | #include <inttypes.h> | |
61c03724 | 24 | #include <stddef.h> |
6b98979f UD |
25 | #include <stdlib.h> |
26 | #include <string.h> | |
27 | #include <unistd.h> | |
0588dfe7 | 28 | #include <sys/cdefs.h> |
6b98979f UD |
29 | #include <sys/param.h> |
30 | ||
31 | ||
32 | struct Strent | |
33 | { | |
34 | const char *string; | |
35 | size_t len; | |
36 | struct Strent *next; | |
37 | struct Strent *left; | |
38 | struct Strent *right; | |
39 | size_t offset; | |
40 | char reverse[0]; | |
41 | }; | |
42 | ||
43 | ||
44 | struct memoryblock | |
45 | { | |
46 | struct memoryblock *next; | |
47 | char memory[0]; | |
48 | }; | |
49 | ||
50 | ||
51 | struct Strtab | |
52 | { | |
53 | struct Strent *root; | |
54 | struct memoryblock *memory; | |
55 | char *backp; | |
56 | size_t left; | |
57 | size_t total; | |
58 | ||
59 | struct Strent null; | |
60 | }; | |
61 | ||
62 | ||
63 | /* Cache for the pagesize. We correct this value a bit so that `malloc' | |
64 | is not allocating more than a page. */ | |
65 | static size_t ps; | |
66 | ||
67 | ||
6ff444c4 | 68 | #include <programs/xmalloc.h> |
6b98979f | 69 | |
f85a7105 AJ |
70 | /* Prototypes for our functions that are used from iconvconfig.c. If |
71 | you change these, change also iconvconfig.c. */ | |
72 | /* Create new C string table object in memory. */ | |
73 | extern struct Strtab *strtabinit (void); | |
74 | ||
75 | /* Free resources allocated for C string table ST. */ | |
76 | extern void strtabfree (struct Strtab *st); | |
77 | ||
78 | /* Add string STR (length LEN is != 0) to C string table ST. */ | |
79 | extern struct Strent *strtabadd (struct Strtab *st, const char *str, | |
80 | size_t len); | |
81 | ||
82 | /* Finalize string table ST and store size in *SIZE and return a pointer. */ | |
83 | extern void *strtabfinalize (struct Strtab *st, size_t *size); | |
84 | ||
85 | /* Get offset in string table for string associated with SE. */ | |
86 | extern size_t strtaboffset (struct Strent *se); | |
87 | ||
6b98979f UD |
88 | |
89 | struct Strtab * | |
90 | strtabinit (void) | |
91 | { | |
71ce28fd UD |
92 | struct Strtab *ret; |
93 | ||
6b98979f UD |
94 | if (ps == 0) |
95 | { | |
61c03724 | 96 | ps = sysconf (_SC_PAGESIZE) - 2 * sizeof (void *); |
6b98979f UD |
97 | assert (sizeof (struct memoryblock) < ps); |
98 | } | |
99 | ||
71ce28fd UD |
100 | ret = (struct Strtab *) calloc (1, sizeof (struct Strtab)); |
101 | if (ret != NULL) | |
102 | { | |
103 | ret->null.len = 1; | |
104 | ret->null.string = ""; | |
105 | } | |
106 | return ret; | |
6b98979f UD |
107 | } |
108 | ||
109 | ||
110 | static void | |
111 | morememory (struct Strtab *st, size_t len) | |
112 | { | |
113 | struct memoryblock *newmem; | |
114 | ||
115 | if (len < ps) | |
116 | len = ps; | |
117 | newmem = (struct memoryblock *) malloc (len); | |
118 | if (newmem == NULL) | |
119 | abort (); | |
120 | ||
121 | newmem->next = st->memory; | |
122 | st->memory = newmem; | |
123 | st->backp = newmem->memory; | |
61c03724 | 124 | st->left = len - offsetof (struct memoryblock, memory); |
6b98979f UD |
125 | } |
126 | ||
127 | ||
128 | void | |
129 | strtabfree (struct Strtab *st) | |
130 | { | |
131 | struct memoryblock *mb = st->memory; | |
132 | ||
133 | while (mb != NULL) | |
134 | { | |
135 | void *old = mb; | |
136 | mb = mb->next; | |
137 | free (old); | |
138 | } | |
139 | ||
140 | free (st); | |
141 | } | |
142 | ||
143 | ||
144 | static struct Strent * | |
145 | newstring (struct Strtab *st, const char *str, size_t len) | |
146 | { | |
147 | struct Strent *newstr; | |
148 | size_t align; | |
149 | int i; | |
150 | ||
6b98979f UD |
151 | /* Compute the amount of padding needed to make the structure aligned. */ |
152 | align = ((__alignof__ (struct Strent) | |
153 | - (((uintptr_t) st->backp) | |
154 | & (__alignof__ (struct Strent) - 1))) | |
155 | & (__alignof__ (struct Strent) - 1)); | |
156 | ||
157 | /* Make sure there is enough room in the memory block. */ | |
158 | if (st->left < align + sizeof (struct Strent) + len) | |
159 | { | |
160 | morememory (st, sizeof (struct Strent) + len); | |
161 | align = 0; | |
162 | } | |
163 | ||
164 | /* Create the reserved string. */ | |
165 | newstr = (struct Strent *) (st->backp + align); | |
166 | newstr->string = str; | |
167 | newstr->len = len; | |
168 | newstr->next = NULL; | |
169 | newstr->left = NULL; | |
170 | newstr->right = NULL; | |
171 | newstr->offset = 0; | |
172 | for (i = len - 2; i >= 0; --i) | |
173 | newstr->reverse[i] = str[len - 2 - i]; | |
174 | newstr->reverse[len - 1] = '\0'; | |
175 | st->backp += align + sizeof (struct Strent) + len; | |
176 | st->left -= align + sizeof (struct Strent) + len; | |
177 | ||
178 | return newstr; | |
179 | } | |
180 | ||
181 | ||
182 | /* XXX This function should definitely be rewritten to use a balancing | |
c0c3f78a | 183 | tree algorithm (AVL, red-black trees). For now a simple, correct |
6b98979f UD |
184 | implementation is enough. */ |
185 | static struct Strent ** | |
186 | searchstring (struct Strent **sep, struct Strent *newstr) | |
187 | { | |
188 | int cmpres; | |
189 | ||
190 | /* More strings? */ | |
191 | if (*sep == NULL) | |
192 | { | |
193 | *sep = newstr; | |
194 | return sep; | |
195 | } | |
196 | ||
197 | /* Compare the strings. */ | |
198 | cmpres = memcmp ((*sep)->reverse, newstr->reverse, | |
c06a49c5 | 199 | MIN ((*sep)->len, newstr->len) - 1); |
6b98979f UD |
200 | if (cmpres == 0) |
201 | /* We found a matching string. */ | |
202 | return sep; | |
203 | else if (cmpres > 0) | |
204 | return searchstring (&(*sep)->left, newstr); | |
205 | else | |
206 | return searchstring (&(*sep)->right, newstr); | |
207 | } | |
208 | ||
209 | ||
210 | /* Add new string. The actual string is assumed to be permanent. */ | |
211 | struct Strent * | |
212 | strtabadd (struct Strtab *st, const char *str, size_t len) | |
213 | { | |
214 | struct Strent *newstr; | |
215 | struct Strent **sep; | |
216 | ||
71ce28fd UD |
217 | /* Compute the string length if the caller doesn't know it. */ |
218 | if (len == 0) | |
219 | len = strlen (str) + 1; | |
220 | ||
221 | /* Make sure all "" strings get offset 0. */ | |
222 | if (len == 1) | |
223 | return &st->null; | |
224 | ||
6b98979f UD |
225 | /* Allocate memory for the new string and its associated information. */ |
226 | newstr = newstring (st, str, len); | |
227 | ||
228 | /* Search in the array for the place to insert the string. If there | |
229 | is no string with matching prefix and no string with matching | |
230 | leading substring, create a new entry. */ | |
231 | sep = searchstring (&st->root, newstr); | |
232 | if (*sep != newstr) | |
233 | { | |
234 | /* This is not the same entry. This means we have a prefix match. */ | |
235 | if ((*sep)->len > newstr->len) | |
236 | { | |
71ce28fd UD |
237 | struct Strent *subs; |
238 | ||
239 | for (subs = (*sep)->next; subs; subs = subs->next) | |
240 | if (subs->len == newstr->len) | |
241 | { | |
242 | /* We have an exact match with a substring. Free the memory | |
243 | we allocated. */ | |
244 | st->left += st->backp - (char *) newstr; | |
245 | st->backp = (char *) newstr; | |
246 | ||
247 | return subs; | |
248 | } | |
249 | ||
6b98979f UD |
250 | /* We have a new substring. This means we don't need the reverse |
251 | string of this entry anymore. */ | |
252 | st->backp -= newstr->len; | |
253 | st->left += newstr->len; | |
254 | ||
255 | newstr->next = (*sep)->next; | |
256 | (*sep)->next = newstr; | |
257 | } | |
258 | else if ((*sep)->len != newstr->len) | |
259 | { | |
260 | /* When we get here it means that the string we are about to | |
261 | add has a common prefix with a string we already have but | |
262 | it is longer. In this case we have to put it first. */ | |
c06a49c5 | 263 | st->total += newstr->len - (*sep)->len; |
6b98979f | 264 | newstr->next = *sep; |
71ce28fd UD |
265 | newstr->left = (*sep)->left; |
266 | newstr->right = (*sep)->right; | |
6b98979f | 267 | *sep = newstr; |
6b98979f UD |
268 | } |
269 | else | |
270 | { | |
271 | /* We have an exact match. Free the memory we allocated. */ | |
272 | st->left += st->backp - (char *) newstr; | |
273 | st->backp = (char *) newstr; | |
274 | ||
275 | newstr = *sep; | |
276 | } | |
277 | } | |
278 | else | |
279 | st->total += newstr->len; | |
280 | ||
281 | return newstr; | |
282 | } | |
283 | ||
284 | ||
285 | static void | |
286 | copystrings (struct Strent *nodep, char **freep, size_t *offsetp) | |
287 | { | |
288 | struct Strent *subs; | |
289 | ||
290 | if (nodep->left != NULL) | |
291 | copystrings (nodep->left, freep, offsetp); | |
292 | ||
293 | /* Process the current node. */ | |
294 | nodep->offset = *offsetp; | |
295 | *freep = (char *) mempcpy (*freep, nodep->string, nodep->len); | |
296 | *offsetp += nodep->len; | |
297 | ||
298 | for (subs = nodep->next; subs != NULL; subs = subs->next) | |
299 | { | |
300 | assert (subs->len < nodep->len); | |
301 | subs->offset = nodep->offset + nodep->len - subs->len; | |
302 | } | |
303 | ||
304 | if (nodep->right != NULL) | |
305 | copystrings (nodep->right, freep, offsetp); | |
306 | } | |
307 | ||
308 | ||
309 | void * | |
310 | strtabfinalize (struct Strtab *st, size_t *size) | |
311 | { | |
312 | size_t copylen; | |
313 | char *endp; | |
314 | char *retval; | |
315 | ||
316 | /* Fill in the information. */ | |
317 | endp = retval = (char *) xmalloc (st->total + 1); | |
318 | ||
319 | /* Always put an empty string at the beginning so that a zero offset | |
320 | can mean error. */ | |
321 | *endp++ = '\0'; | |
322 | ||
323 | /* Now run through the tree and add all the string while also updating | |
324 | the offset members of the elfstrent records. */ | |
325 | copylen = 1; | |
326 | copystrings (st->root, &endp, ©len); | |
327 | assert (copylen == st->total + 1); | |
f9f7fcbe | 328 | assert (endp == retval + st->total + 1); |
6b98979f UD |
329 | *size = copylen; |
330 | ||
331 | return retval; | |
332 | } | |
333 | ||
334 | ||
335 | size_t | |
336 | strtaboffset (struct Strent *se) | |
337 | { | |
338 | return se->offset; | |
339 | } |