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 = CALLOC(1, 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 "
54 struct lookup_table_entry *new_lookup_table_entry()
56 struct lookup_table_entry *lte;
58 lte = MALLOC(sizeof(struct lookup_table_entry));
60 ERROR("Out of memory (tried to allocate %zu bytes for "
61 "lookup table entry)\n",
62 sizeof(struct lookup_table_entry));
66 lte->file_on_disk = NULL;
67 lte->other_wim_fp = NULL;
71 lte->staging_num_times_opened = 0;
78 * Inserts an entry into the lookup table.
80 * @lookup_table: A pointer to the lookup table.
81 * @entry: A pointer to the entry to insert.
83 void lookup_table_insert(struct lookup_table *table,
84 struct lookup_table_entry *lte)
87 pos = *(size_t*)lte->hash % table->capacity;
88 lte->next = table->array[pos];
89 table->array[pos] = lte;
90 /* XXX Make the table grow when too many entries have been inserted. */
95 /* Unlinks a lookup table entry from the table; does not free it. */
96 void lookup_table_unlink(struct lookup_table *table,
97 struct lookup_table_entry *lte)
100 struct lookup_table_entry *prev, *cur_entry, *next;
102 pos = *(size_t*)lte->hash % table->capacity;
104 cur_entry = table->array[pos];
107 next = cur_entry->next;
108 if (cur_entry == lte) {
112 table->array[pos] = next;
113 table->num_entries--;
122 /* Decrement the reference count for the dentry having hash value @hash in the
123 * lookup table. The lookup table entry is unlinked and freed if there are no
124 * references to in remaining. */
125 void lookup_table_decrement_refcnt(struct lookup_table* table, const u8 hash[])
127 size_t pos = *(size_t*)hash % table->capacity;
128 struct lookup_table_entry *prev = NULL;
129 struct lookup_table_entry *entry = table->array[pos];
130 struct lookup_table_entry *next;
133 if (memcmp(hash, entry->hash, WIM_HASH_SIZE) == 0) {
134 wimlib_assert(entry->refcnt != 0);
135 if (--entry->refcnt == 0) {
136 free_lookup_table_entry(entry);
140 table->array[pos] = next;
149 * Looks up an entry in the lookup table.
151 struct lookup_table_entry *lookup_resource(const struct lookup_table *lookup_table,
155 struct lookup_table_entry *lte;
157 pos = *(size_t*)hash % lookup_table->capacity;
158 lte = lookup_table->array[pos];
160 if (memcmp(hash, lte->hash, WIM_HASH_SIZE) == 0)
168 * Calls a function on all the entries in the lookup table. Stop early and
169 * return nonzero if any call to the function returns nonzero.
171 int for_lookup_table_entry(struct lookup_table *table,
172 int (*visitor)(struct lookup_table_entry *, void *), void *arg)
174 struct lookup_table_entry *entry, *next;
178 for (i = 0; i < table->capacity; i++) {
179 entry = table->array[i];
182 ret = visitor(entry, arg);
193 * Reads the lookup table from a WIM file.
195 * @fp: The FILE* for the WIM file.
196 * @offset: The offset of the lookup table resource.
197 * @size: The size of the lookup table resource.
198 * @lookup_table_ret: A pointer to a struct lookup_table structure into which the
199 * lookup table will be returned.
200 * @return: True on success, false on failure.
202 int read_lookup_table(FILE *fp, u64 offset, u64 size,
203 struct lookup_table **table_ret)
206 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
208 struct lookup_table *table;
210 struct lookup_table_entry *cur_entry;
212 DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"\n",
215 if (fseeko(fp, offset, SEEK_SET) != 0) {
216 ERROR("Failed to seek to byte %"PRIu64" to read lookup table: "
218 return WIMLIB_ERR_READ;
221 num_entries = size / WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
222 table = new_lookup_table(num_entries * 2 + 1);
224 return WIMLIB_ERR_NOMEM;
226 while (num_entries--) {
227 if (fread(buf, 1, sizeof(buf), fp) != sizeof(buf)) {
229 ERROR("Unexpected EOF in lookup table!\n");
231 ERROR("Stream read error while reading "
234 ret = WIMLIB_ERR_READ;
237 cur_entry = new_lookup_table_entry();
239 ret = WIMLIB_ERR_NOMEM;
243 p = get_resource_entry(buf, &cur_entry->resource_entry);
244 p = get_u16(p, &cur_entry->part_number);
245 p = get_u32(p, &cur_entry->refcnt);
246 p = get_bytes(p, sizeof(cur_entry->hash), cur_entry->hash);
247 lookup_table_insert(table, cur_entry);
249 DEBUG("Done reading lookup table.\n");
253 free_lookup_table(table);
259 * Writes a lookup table entry to the output file.
261 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
264 u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
269 /* do not write lookup table entries for empty files */
270 if (lte->output_resource_entry.original_size == 0)
273 /* Don't write entries that have not had file resources or metadata
274 * resources written for them. */
275 if (lte->out_refcnt == 0)
278 if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
279 DEBUG("Writing metadata entry at %lu\n", ftello(out));
281 p = put_resource_entry(buf, <e->output_resource_entry);
282 p = put_u16(p, lte->part_number);
283 p = put_u32(p, lte->out_refcnt);
284 p = put_bytes(p, WIM_HASH_SIZE, lte->hash);
285 if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
286 ERROR("Failed to write lookup table entry: %m\n");
287 return WIMLIB_ERR_WRITE;
292 static int do_free_lookup_table_entry(struct lookup_table_entry *entry, void *ignore)
294 free_lookup_table_entry(entry);
298 void free_lookup_table(struct lookup_table *table)
302 for_lookup_table_entry(table,
303 do_free_lookup_table_entry,
311 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
313 entry->out_refcnt = 0;
317 int print_lookup_table_entry(struct lookup_table_entry *entry, void *ignore)
319 printf("Offset = %"PRIu64" bytes\n",
320 entry->resource_entry.offset);
321 printf("Size = %"PRIu64" bytes\n",
322 (u64)entry->resource_entry.size);
323 printf("Original size = %"PRIu64" bytes\n",
324 entry->resource_entry.original_size);
325 printf("Part Number = %hu\n", entry->part_number);
326 printf("Reference Count = %u\n", entry->refcnt);
328 print_hash(entry->hash);
331 u8 flags = entry->resource_entry.flags;
332 if (flags & WIM_RESHDR_FLAG_COMPRESSED)
333 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
334 if (flags & WIM_RESHDR_FLAG_FREE)
335 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
336 if (flags & WIM_RESHDR_FLAG_METADATA)
337 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
338 if (flags & WIM_RESHDR_FLAG_SPANNED)
339 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
341 if (entry->file_on_disk)
342 printf("File on Disk = \"%s\"\n", entry->file_on_disk);
348 * Prints the lookup table of a WIM file.
350 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
352 for_lookup_table_entry(w->lookup_table,
353 print_lookup_table_entry, NULL);