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 void 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 free_lookup_table_entry(entry);
136 table->array[pos] = next;
145 * Looks up an entry in the lookup table.
147 struct lookup_table_entry *lookup_resource(const struct lookup_table *lookup_table,
151 struct lookup_table_entry *lte;
153 pos = *(size_t*)hash % lookup_table->capacity;
154 lte = lookup_table->array[pos];
156 if (memcmp(hash, lte->hash, WIM_HASH_SIZE) == 0)
164 * Calls a function on all the entries in the lookup table. Stop early and
165 * return nonzero if any call to the function returns nonzero.
167 int for_lookup_table_entry(struct lookup_table *table,
168 int (*visitor)(struct lookup_table_entry *, void *),
171 struct lookup_table_entry *entry, *next;
175 for (i = 0; i < table->capacity; i++) {
176 entry = table->array[i];
179 ret = visitor(entry, arg);
190 * Reads the lookup table from a WIM file.
192 * @fp: The FILE* for the WIM file.
193 * @offset: The offset of the lookup table resource.
194 * @size: The size of the lookup table resource.
195 * @lookup_table_ret: A pointer to a struct lookup_table structure into which the
196 * lookup table will be returned.
197 * @return: True on success, false on failure.
199 int read_lookup_table(FILE *fp, u64 offset, u64 size,
200 struct lookup_table **table_ret)
203 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
205 struct lookup_table *table;
207 struct lookup_table_entry *cur_entry;
209 DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
212 if (fseeko(fp, offset, SEEK_SET) != 0) {
213 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
214 "lookup table", offset);
215 return WIMLIB_ERR_READ;
218 num_entries = size / WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
219 table = new_lookup_table(num_entries * 2 + 1);
221 return WIMLIB_ERR_NOMEM;
223 while (num_entries--) {
224 if (fread(buf, 1, sizeof(buf), fp) != sizeof(buf)) {
226 ERROR("Unexpected EOF in WIM lookup table!");
228 ERROR_WITH_ERRNO("Error reading WIM lookup "
231 ret = WIMLIB_ERR_READ;
234 cur_entry = new_lookup_table_entry();
236 ret = WIMLIB_ERR_NOMEM;
240 p = get_resource_entry(buf, &cur_entry->resource_entry);
241 p = get_u16(p, &cur_entry->part_number);
242 p = get_u32(p, &cur_entry->refcnt);
243 p = get_bytes(p, WIM_HASH_SIZE, cur_entry->hash);
244 lookup_table_insert(table, cur_entry);
246 DEBUG("Done reading lookup table.");
250 free_lookup_table(table);
256 * Writes a lookup table entry to the output file.
258 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
261 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
266 /* do not write lookup table entries for empty files */
267 if (lte->output_resource_entry.original_size == 0)
270 /* Don't write entries that have not had file resources or metadata
271 * resources written for them. */
272 if (lte->out_refcnt == 0)
275 if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
276 DEBUG("Writing metadata entry at %lu", ftello(out));
278 p = put_resource_entry(buf, <e->output_resource_entry);
279 p = put_u16(p, lte->part_number);
280 p = put_u32(p, lte->out_refcnt);
281 p = put_bytes(p, WIM_HASH_SIZE, lte->hash);
282 if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
283 ERROR_WITH_ERRNO("Failed to write lookup table entry");
284 return WIMLIB_ERR_WRITE;
289 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
292 free_lookup_table_entry(entry);
296 void free_lookup_table(struct lookup_table *table)
301 for_lookup_table_entry(table, do_free_lookup_table_entry, NULL);
307 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
309 entry->out_refcnt = 0;
313 int print_lookup_table_entry(struct lookup_table_entry *entry, void *ignore)
315 printf("Offset = %"PRIu64" bytes\n",
316 entry->resource_entry.offset);
317 printf("Size = %"PRIu64" bytes\n",
318 (u64)entry->resource_entry.size);
319 printf("Original size = %"PRIu64" bytes\n",
320 entry->resource_entry.original_size);
321 printf("Part Number = %hu\n", entry->part_number);
322 printf("Reference Count = %u\n", entry->refcnt);
324 print_hash(entry->hash);
327 u8 flags = entry->resource_entry.flags;
328 if (flags & WIM_RESHDR_FLAG_COMPRESSED)
329 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
330 if (flags & WIM_RESHDR_FLAG_FREE)
331 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
332 if (flags & WIM_RESHDR_FLAG_METADATA)
333 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
334 if (flags & WIM_RESHDR_FLAG_SPANNED)
335 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
337 if (entry->file_on_disk)
338 printf("File on Disk = `%s'\n", entry->file_on_disk);
344 * Prints the lookup table of a WIM file.
346 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
348 for_lookup_table_entry(w->lookup_table,
349 print_lookup_table_entry, NULL);