lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* C string table handling. |
| 2 | Copyright (C) 2000-2015 Free Software Foundation, Inc. |
| 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 |
| 16 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #ifdef HAVE_CONFIG_H |
| 19 | # include <config.h> |
| 20 | #endif |
| 21 | |
| 22 | #include <assert.h> |
| 23 | #include <inttypes.h> |
| 24 | #include <stddef.h> |
| 25 | #include <stdlib.h> |
| 26 | #include <string.h> |
| 27 | #include <unistd.h> |
| 28 | #include <sys/cdefs.h> |
| 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 | |
| 68 | #include <programs/xmalloc.h> |
| 69 | |
| 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 | |
| 88 | |
| 89 | struct Strtab * |
| 90 | strtabinit (void) |
| 91 | { |
| 92 | struct Strtab *ret; |
| 93 | |
| 94 | if (ps == 0) |
| 95 | { |
| 96 | ps = sysconf (_SC_PAGESIZE) - 2 * sizeof (void *); |
| 97 | assert (sizeof (struct memoryblock) < ps); |
| 98 | } |
| 99 | |
| 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; |
| 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; |
| 124 | st->left = len - offsetof (struct memoryblock, memory); |
| 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 | |
| 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 |
| 183 | tree algorithm (AVL, red-black trees). For now a simple, correct |
| 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, |
| 199 | MIN ((*sep)->len, newstr->len) - 1); |
| 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 | |
| 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 | |
| 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 | { |
| 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 | |
| 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. */ |
| 263 | st->total += newstr->len - (*sep)->len; |
| 264 | newstr->next = *sep; |
| 265 | newstr->left = (*sep)->left; |
| 266 | newstr->right = (*sep)->right; |
| 267 | *sep = newstr; |
| 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); |
| 328 | assert (endp == retval + st->total + 1); |
| 329 | *size = copylen; |
| 330 | |
| 331 | return retval; |
| 332 | } |
| 333 | |
| 334 | |
| 335 | size_t |
| 336 | strtaboffset (struct Strent *se) |
| 337 | { |
| 338 | return se->offset; |
| 339 | } |