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"
31 struct lookup_table *new_lookup_table(size_t capacity)
33 struct lookup_table *table;
34 struct lookup_table_entry **array;
36 table = MALLOC(sizeof(struct lookup_table));
39 array = CALLOC(capacity, sizeof(array[0]));
44 table->num_entries = 0;
45 table->capacity = capacity;
49 ERROR("Failed to allocate memory for lookup table with capacity %zu",
54 struct lookup_table_entry *new_lookup_table_entry()
56 struct lookup_table_entry *lte;
58 lte = CALLOC(1, sizeof(struct lookup_table_entry));
60 ERROR("Out of memory (tried to allocate %zu bytes for "
61 "lookup table entry)",
62 sizeof(struct lookup_table_entry));
74 * Inserts an entry into the lookup table.
76 * @lookup_table: A pointer to the lookup table.
77 * @entry: A pointer to the entry to insert.
79 void lookup_table_insert(struct lookup_table *table,
80 struct lookup_table_entry *lte)
83 pos = lte->hash_short % table->capacity;
84 lte->next = table->array[pos];
85 table->array[pos] = lte;
86 /* XXX Make the table grow when too many entries have been inserted. */
91 /* Unlinks a lookup table entry from the table; does not free it. */
92 void lookup_table_unlink(struct lookup_table *table,
93 struct lookup_table_entry *lte)
96 struct lookup_table_entry *prev, *cur_entry, *next;
98 pos = lte->hash_short % table->capacity;
100 cur_entry = table->array[pos];
103 next = cur_entry->next;
104 if (cur_entry == lte) {
108 table->array[pos] = next;
109 table->num_entries--;
118 /* Decrement the reference count for the dentry having hash value @hash in the
119 * lookup table. The lookup table entry is unlinked and freed if there are no
120 * references to in remaining. */
121 bool lookup_table_decrement_refcnt(struct lookup_table* table, const u8 hash[])
123 size_t pos = *(size_t*)hash % table->capacity;
124 struct lookup_table_entry *prev = NULL;
125 struct lookup_table_entry *entry = table->array[pos];
126 struct lookup_table_entry *next;
129 if (memcmp(hash, entry->hash, WIM_HASH_SIZE) == 0) {
130 wimlib_assert(entry->refcnt != 0);
131 if (--entry->refcnt == 0) {
132 if (entry->num_opened_fds == 0)
133 free_lookup_table_entry(entry);
137 table->array[pos] = next;
149 * Calls a function on all the entries in the lookup table. Stop early and
150 * return nonzero if any call to the function returns nonzero.
152 int for_lookup_table_entry(struct lookup_table *table,
153 int (*visitor)(struct lookup_table_entry *, void *),
156 struct lookup_table_entry *entry, *next;
160 for (i = 0; i < table->capacity; i++) {
161 entry = table->array[i];
164 ret = visitor(entry, arg);
175 * Reads the lookup table from a WIM file.
177 * @fp: The FILE* for the WIM file.
178 * @offset: The offset of the lookup table resource.
179 * @size: The size of the lookup table resource.
180 * @lookup_table_ret: A pointer to a struct lookup_table structure into which the
181 * lookup table will be returned.
182 * @return: True on success, false on failure.
184 int read_lookup_table(FILE *fp, u64 offset, u64 size,
185 struct lookup_table **table_ret)
188 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
190 struct lookup_table *table;
192 struct lookup_table_entry *cur_entry;
194 DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
197 if (fseeko(fp, offset, SEEK_SET) != 0) {
198 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
199 "lookup table", offset);
200 return WIMLIB_ERR_READ;
203 num_entries = size / WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
204 table = new_lookup_table(num_entries * 2 + 1);
206 return WIMLIB_ERR_NOMEM;
208 while (num_entries--) {
209 if (fread(buf, 1, sizeof(buf), fp) != sizeof(buf)) {
211 ERROR("Unexpected EOF in WIM lookup table!");
213 ERROR_WITH_ERRNO("Error reading WIM lookup "
216 ret = WIMLIB_ERR_READ;
219 cur_entry = new_lookup_table_entry();
221 ret = WIMLIB_ERR_NOMEM;
225 p = get_resource_entry(buf, &cur_entry->resource_entry);
226 p = get_u16(p, &cur_entry->part_number);
227 p = get_u32(p, &cur_entry->refcnt);
228 p = get_bytes(p, WIM_HASH_SIZE, cur_entry->hash);
229 lookup_table_insert(table, cur_entry);
231 DEBUG("Done reading lookup table.");
235 free_lookup_table(table);
241 * Writes a lookup table entry to the output file.
243 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
246 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
251 /* do not write lookup table entries for empty files */
252 if (lte->output_resource_entry.original_size == 0)
255 /* Don't write entries that have not had file resources or metadata
256 * resources written for them. */
257 if (lte->out_refcnt == 0)
260 if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
261 DEBUG("Writing metadata entry at %lu", ftello(out));
263 p = put_resource_entry(buf, <e->output_resource_entry);
264 p = put_u16(p, lte->part_number);
265 p = put_u32(p, lte->out_refcnt);
266 p = put_bytes(p, WIM_HASH_SIZE, lte->hash);
267 if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
268 ERROR_WITH_ERRNO("Failed to write lookup table entry");
269 return WIMLIB_ERR_WRITE;
274 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
277 free_lookup_table_entry(entry);
281 void free_lookup_table(struct lookup_table *table)
286 for_lookup_table_entry(table, do_free_lookup_table_entry, NULL);
292 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
294 entry->out_refcnt = 0;
298 int print_lookup_table_entry(struct lookup_table_entry *entry, void *ignore)
300 printf("Offset = %"PRIu64" bytes\n",
301 entry->resource_entry.offset);
302 printf("Size = %"PRIu64" bytes\n",
303 (u64)entry->resource_entry.size);
304 printf("Original size = %"PRIu64" bytes\n",
305 entry->resource_entry.original_size);
306 printf("Part Number = %hu\n", entry->part_number);
307 printf("Reference Count = %u\n", entry->refcnt);
309 print_hash(entry->hash);
312 u8 flags = entry->resource_entry.flags;
313 if (flags & WIM_RESHDR_FLAG_COMPRESSED)
314 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
315 if (flags & WIM_RESHDR_FLAG_FREE)
316 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
317 if (flags & WIM_RESHDR_FLAG_METADATA)
318 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
319 if (flags & WIM_RESHDR_FLAG_SPANNED)
320 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
322 if (entry->file_on_disk)
323 printf("File on Disk = `%s'\n", entry->file_on_disk);
329 * Prints the lookup table of a WIM file.
331 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
333 for_lookup_table_entry(w->lookup_table,
334 print_lookup_table_entry, NULL);
338 * Looks up an entry in the lookup table.
340 struct lookup_table_entry *
341 __lookup_resource(const struct lookup_table *lookup_table, const u8 hash[])
344 struct lookup_table_entry *lte;
346 pos = *(size_t*)hash % lookup_table->capacity;
347 lte = lookup_table->array[pos];
349 if (memcmp(hash, lte->hash, WIM_HASH_SIZE) == 0)
356 int lookup_resource(WIMStruct *w, const char *path,
358 struct dentry **dentry_ret,
359 struct lookup_table_entry **lte_ret,
362 struct dentry *dentry = get_dentry(w, path);
363 struct lookup_table_entry *lte;
367 if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
368 && dentry_is_directory(dentry))
370 if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
371 const char *stream_name = path_stream_name(path);
373 for (u16 i = 0; i < dentry->num_ads; i++) {
374 if (strcmp(stream_name, dentry->ads_entries[i].stream_name) == 0) {
375 hash = dentry->ads_entries[i].hash;
384 lte = __lookup_resource(w->lookup_table, hash);
386 *dentry_ret = dentry;