4 * Lookup table, implemented as a hash table, that maps dentries to file
9 * Copyright (C) 2012 Eric Biggers
11 * This file is part of wimlib, a library for working with WIM files.
13 * wimlib is free software; you can redistribute it and/or modify it under the
14 * terms of the GNU Lesser General Public License as published by the Free
15 * Software Foundation; either version 2.1 of the License, or (at your option)
18 * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
19 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
20 * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
23 * You should have received a copy of the GNU Lesser General Public License
24 * along with wimlib; if not, see http://www.gnu.org/licenses/.
27 #include "wimlib_internal.h"
28 #include "lookup_table.h"
32 struct lookup_table *new_lookup_table(size_t capacity)
34 struct lookup_table *table;
35 struct lookup_table_entry **array;
37 table = MALLOC(sizeof(struct lookup_table));
40 array = CALLOC(capacity, sizeof(array[0]));
45 table->num_entries = 0;
46 table->capacity = capacity;
50 ERROR("Failed to allocate memory for lookup table with capacity %zu",
55 struct lookup_table_entry *new_lookup_table_entry()
57 struct lookup_table_entry *lte;
59 lte = CALLOC(1, sizeof(struct lookup_table_entry));
61 ERROR("Out of memory (tried to allocate %zu bytes for "
62 "lookup table entry)",
63 sizeof(struct lookup_table_entry));
73 void free_lookup_table_entry(struct lookup_table_entry *lte)
76 if (lte->staging_list.next)
77 list_del(<e->staging_list);
78 FREE(lte->file_on_disk);
84 * Inserts an entry into the lookup table.
86 * @lookup_table: A pointer to the lookup table.
87 * @entry: A pointer to the entry to insert.
89 void lookup_table_insert(struct lookup_table *table,
90 struct lookup_table_entry *lte)
93 pos = lte->hash_short % table->capacity;
94 lte->next = table->array[pos];
95 table->array[pos] = lte;
96 /* XXX Make the table grow when too many entries have been inserted. */
101 /* Unlinks a lookup table entry from the table; does not free it. */
102 void lookup_table_unlink(struct lookup_table *table,
103 struct lookup_table_entry *lte)
106 struct lookup_table_entry *prev, *cur_entry, *next;
108 pos = lte->hash_short % table->capacity;
110 cur_entry = table->array[pos];
113 next = cur_entry->next;
114 if (cur_entry == lte) {
118 table->array[pos] = next;
119 table->num_entries--;
128 /* Decrement the reference count for the dentry having hash value @hash in the
129 * lookup table. The lookup table entry is unlinked and freed if there are no
130 * references to in remaining. */
131 struct lookup_table_entry *
132 lookup_table_decrement_refcnt(struct lookup_table* table, const u8 hash[])
134 size_t pos = *(size_t*)hash % table->capacity;
135 struct lookup_table_entry *prev = NULL;
136 struct lookup_table_entry *entry = table->array[pos];
137 struct lookup_table_entry *next;
140 if (memcmp(hash, entry->hash, WIM_HASH_SIZE) == 0) {
141 wimlib_assert(entry->refcnt != 0);
142 if (--entry->refcnt == 0) {
143 if (entry->num_opened_fds == 0) {
144 free_lookup_table_entry(entry);
150 table->array[pos] = next;
162 * Calls a function on all the entries in the lookup table. Stop early and
163 * return nonzero if any call to the function returns nonzero.
165 int for_lookup_table_entry(struct lookup_table *table,
166 int (*visitor)(struct lookup_table_entry *, void *),
169 struct lookup_table_entry *entry, *next;
173 for (i = 0; i < table->capacity; i++) {
174 entry = table->array[i];
177 ret = visitor(entry, arg);
188 * Reads the lookup table from a WIM file.
190 * @fp: The FILE* for the WIM file.
191 * @offset: The offset of the lookup table resource.
192 * @size: The size of the lookup table resource.
193 * @lookup_table_ret: A pointer to a struct lookup_table structure into which the
194 * lookup table will be returned.
195 * @return: True on success, false on failure.
197 int read_lookup_table(FILE *fp, u64 offset, u64 size,
198 struct lookup_table **table_ret)
201 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
203 struct lookup_table *table;
205 struct lookup_table_entry *cur_entry;
207 DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
210 if (fseeko(fp, offset, SEEK_SET) != 0) {
211 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
212 "lookup table", offset);
213 return WIMLIB_ERR_READ;
216 num_entries = size / WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
217 table = new_lookup_table(num_entries * 2 + 1);
219 return WIMLIB_ERR_NOMEM;
221 while (num_entries--) {
222 if (fread(buf, 1, sizeof(buf), fp) != sizeof(buf)) {
224 ERROR("Unexpected EOF in WIM lookup table!");
226 ERROR_WITH_ERRNO("Error reading WIM lookup "
229 ret = WIMLIB_ERR_READ;
232 cur_entry = new_lookup_table_entry();
234 ret = WIMLIB_ERR_NOMEM;
238 p = get_resource_entry(buf, &cur_entry->resource_entry);
239 p = get_u16(p, &cur_entry->part_number);
240 p = get_u32(p, &cur_entry->refcnt);
241 p = get_bytes(p, WIM_HASH_SIZE, cur_entry->hash);
242 lookup_table_insert(table, cur_entry);
244 DEBUG("Done reading lookup table.");
248 free_lookup_table(table);
254 * Writes a lookup table entry to the output file.
256 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
259 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
264 /* do not write lookup table entries for empty files */
265 if (lte->output_resource_entry.original_size == 0)
268 /* Don't write entries that have not had file resources or metadata
269 * resources written for them. */
270 if (lte->out_refcnt == 0)
273 if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
274 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
275 ftello(out), lte->output_resource_entry.original_size);
277 p = put_resource_entry(buf, <e->output_resource_entry);
278 p = put_u16(p, lte->part_number);
279 p = put_u32(p, lte->out_refcnt);
280 p = put_bytes(p, WIM_HASH_SIZE, lte->hash);
281 if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
282 ERROR_WITH_ERRNO("Failed to write lookup table entry");
283 return WIMLIB_ERR_WRITE;
288 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
291 free_lookup_table_entry(entry);
295 void free_lookup_table(struct lookup_table *table)
300 for_lookup_table_entry(table, do_free_lookup_table_entry, NULL);
306 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
308 entry->out_refcnt = 0;
312 int print_lookup_table_entry(struct lookup_table_entry *entry, void *ignore)
314 printf("Offset = %"PRIu64" bytes\n",
315 entry->resource_entry.offset);
316 printf("Size = %"PRIu64" bytes\n",
317 (u64)entry->resource_entry.size);
318 printf("Original size = %"PRIu64" bytes\n",
319 entry->resource_entry.original_size);
320 printf("Part Number = %hu\n", entry->part_number);
321 printf("Reference Count = %u\n", entry->refcnt);
323 print_hash(entry->hash);
326 u8 flags = entry->resource_entry.flags;
327 if (flags & WIM_RESHDR_FLAG_COMPRESSED)
328 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
329 if (flags & WIM_RESHDR_FLAG_FREE)
330 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
331 if (flags & WIM_RESHDR_FLAG_METADATA)
332 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
333 if (flags & WIM_RESHDR_FLAG_SPANNED)
334 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
336 if (entry->file_on_disk)
337 printf("File on Disk = `%s'\n", entry->file_on_disk);
343 * Prints the lookup table of a WIM file.
345 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
347 for_lookup_table_entry(w->lookup_table,
348 print_lookup_table_entry, NULL);
352 * Looks up an entry in the lookup table.
354 struct lookup_table_entry *
355 __lookup_resource(const struct lookup_table *lookup_table, const u8 hash[])
358 struct lookup_table_entry *lte;
360 pos = *(size_t*)hash % lookup_table->capacity;
361 lte = lookup_table->array[pos];
363 if (memcmp(hash, lte->hash, WIM_HASH_SIZE) == 0)
370 int lookup_resource(WIMStruct *w, const char *path,
372 struct dentry **dentry_ret,
373 struct lookup_table_entry **lte_ret,
374 unsigned *stream_idx_ret)
376 struct dentry *dentry = get_dentry(w, path);
377 struct lookup_table_entry *lte;
378 unsigned stream_idx = 0;
379 const u8 *hash = dentry->hash;
382 if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
383 && dentry_is_directory(dentry))
385 if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
386 const char *stream_name = path_stream_name(path);
388 size_t stream_name_len = strlen(stream_name);
389 for (u16 i = 0; i < dentry->num_ads; i++) {
390 if (ads_entry_has_name(&dentry->ads_entries[i],
395 hash = dentry->ads_entries[i].hash;
403 lte = __lookup_resource(w->lookup_table, hash);
405 *dentry_ret = dentry;
409 *stream_idx_ret = stream_idx;