Coverage Report

Created: 2026-04-01 07:49

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
/src/libzip/lib/zip_hash.c
Line
Count
Source
1
/*
2
  zip_hash.c -- hash table string -> uint64
3
  Copyright (C) 2015-2024 Dieter Baron and Thomas Klausner
4
5
  This file is part of libzip, a library to manipulate ZIP archives.
6
  The authors can be contacted at <info@libzip.org>
7
8
  Redistribution and use in source and binary forms, with or without
9
  modification, are permitted provided that the following conditions
10
  are met:
11
  1. Redistributions of source code must retain the above copyright
12
     notice, this list of conditions and the following disclaimer.
13
  2. Redistributions in binary form must reproduce the above copyright
14
     notice, this list of conditions and the following disclaimer in
15
     the documentation and/or other materials provided with the
16
     distribution.
17
  3. The names of the authors may not be used to endorse or promote
18
     products derived from this software without specific prior
19
     written permission.
20
21
  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
22
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
29
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
31
  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32
*/
33
34
#include "zipint.h"
35
#include <stdlib.h>
36
#include <string.h>
37
38
/* parameter for the string hash function */
39
0
#define HASH_MULTIPLIER 33
40
0
#define HASH_START 5381
41
42
/* hash table's fill ratio is kept between these by doubling/halfing its size as necessary */
43
0
#define HASH_MAX_FILL .75
44
0
#define HASH_MIN_FILL .01
45
46
/* but hash table size is kept between these */
47
0
#define HASH_MIN_SIZE 256
48
0
#define HASH_MAX_SIZE 0x80000000ul
49
50
struct zip_hash_entry {
51
    const zip_uint8_t *name;
52
    zip_int64_t orig_index;
53
    zip_int64_t current_index;
54
    struct zip_hash_entry *next;
55
    zip_uint32_t hash_value;
56
};
57
typedef struct zip_hash_entry zip_hash_entry_t;
58
59
struct zip_hash {
60
    zip_uint32_t table_size;
61
    zip_uint64_t nentries;
62
    zip_hash_entry_t **table;
63
};
64
65
66
/* free list of entries */
67
0
static void free_list(zip_hash_entry_t *entry) {
68
0
    while (entry != NULL) {
69
0
        zip_hash_entry_t *next = entry->next;
70
0
        free(entry);
71
0
        entry = next;
72
0
    }
73
0
}
74
75
76
/* compute hash of string, full 32 bit value */
77
0
static zip_uint32_t hash_string(const zip_uint8_t *name) {
78
0
    zip_uint64_t value = HASH_START;
79
80
0
    if (name == NULL) {
81
0
        return 0;
82
0
    }
83
84
0
    while (*name != 0) {
85
0
        value = (zip_uint64_t)(((value * HASH_MULTIPLIER) + (zip_uint8_t)*name) % 0x100000000ul);
86
0
        name++;
87
0
    }
88
89
0
    return (zip_uint32_t)value;
90
0
}
91
92
93
/* resize hash table; new_size must be a power of 2, can be larger or smaller than current size */
94
0
static bool hash_resize(zip_hash_t *hash, zip_uint32_t new_size, zip_error_t *error) {
95
0
    zip_hash_entry_t **new_table;
96
97
0
    if (new_size == hash->table_size) {
98
0
        return true;
99
0
    }
100
101
0
    if ((new_table = (zip_hash_entry_t **)calloc(new_size, sizeof(zip_hash_entry_t *))) == NULL) {
102
0
        zip_error_set(error, ZIP_ER_MEMORY, 0);
103
0
        return false;
104
0
    }
105
106
0
    if (hash->nentries > 0) {
107
0
        zip_uint32_t i;
108
109
0
        for (i = 0; i < hash->table_size; i++) {
110
0
            zip_hash_entry_t *entry = hash->table[i];
111
0
            while (entry) {
112
0
                zip_hash_entry_t *next = entry->next;
113
114
0
                zip_uint32_t new_index = entry->hash_value % new_size;
115
116
0
                entry->next = new_table[new_index];
117
0
                new_table[new_index] = entry;
118
119
0
                entry = next;
120
0
            }
121
0
        }
122
0
    }
123
124
0
    free(hash->table);
125
0
    hash->table = new_table;
126
0
    hash->table_size = new_size;
127
128
0
    return true;
129
0
}
130
131
132
0
static zip_uint32_t size_for_capacity(zip_uint64_t capacity) {
133
0
    double needed_size = capacity / HASH_MAX_FILL;
134
0
    zip_uint32_t v;
135
136
0
    if (needed_size > ZIP_UINT32_MAX) {
137
0
        v = ZIP_UINT32_MAX;
138
0
    }
139
0
    else {
140
0
        v = (zip_uint32_t)needed_size;
141
0
    }
142
143
0
    if (v > HASH_MAX_SIZE) {
144
0
        return HASH_MAX_SIZE;
145
0
    }
146
147
    /* From Bit Twiddling Hacks by Sean Eron Anderson <seander@cs.stanford.edu>
148
     (http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2). */
149
150
0
    v--;
151
0
    v |= v >> 1;
152
0
    v |= v >> 2;
153
0
    v |= v >> 4;
154
0
    v |= v >> 8;
155
0
    v |= v >> 16;
156
0
    v++;
157
158
0
    return v;
159
0
}
160
161
162
0
zip_hash_t *_zip_hash_new(zip_error_t *error) {
163
0
    zip_hash_t *hash;
164
165
0
    if ((hash = (zip_hash_t *)malloc(sizeof(zip_hash_t))) == NULL) {
166
0
        zip_error_set(error, ZIP_ER_MEMORY, 0);
167
0
        return NULL;
168
0
    }
169
170
0
    hash->table_size = 0;
171
0
    hash->nentries = 0;
172
0
    hash->table = NULL;
173
174
0
    return hash;
175
0
}
176
177
178
0
void _zip_hash_free(zip_hash_t *hash) {
179
0
    zip_uint32_t i;
180
181
0
    if (hash == NULL) {
182
0
        return;
183
0
    }
184
185
0
    if (hash->table != NULL) {
186
0
        for (i = 0; i < hash->table_size; i++) {
187
0
            if (hash->table[i] != NULL) {
188
0
                free_list(hash->table[i]);
189
0
            }
190
0
        }
191
0
        free(hash->table);
192
0
    }
193
0
    free(hash);
194
0
}
195
196
197
/* insert into hash, return error on existence or memory issues */
198
0
bool _zip_hash_add(zip_hash_t *hash, const zip_uint8_t *name, zip_uint64_t index, zip_flags_t flags, zip_error_t *error) {
199
0
    zip_uint32_t hash_value, table_index;
200
0
    zip_hash_entry_t *entry;
201
202
0
    if (hash == NULL || name == NULL || index > ZIP_INT64_MAX) {
203
0
        zip_error_set(error, ZIP_ER_INVAL, 0);
204
0
        return false;
205
0
    }
206
207
0
    if (hash->table_size == 0) {
208
0
        if (!hash_resize(hash, HASH_MIN_SIZE, error)) {
209
0
            return false;
210
0
        }
211
0
    }
212
213
0
    hash_value = hash_string(name);
214
0
    table_index = hash_value % hash->table_size;
215
216
0
    for (entry = hash->table[table_index]; entry != NULL; entry = entry->next) {
217
0
        if (entry->hash_value == hash_value && strcmp((const char *)name, (const char *)entry->name) == 0) {
218
0
            if (((flags & ZIP_FL_UNCHANGED) && entry->orig_index != -1) || entry->current_index != -1) {
219
0
                zip_error_set(error, ZIP_ER_EXISTS, 0);
220
0
                return false;
221
0
            }
222
0
            else {
223
0
                break;
224
0
            }
225
0
        }
226
0
    }
227
228
0
    if (entry == NULL) {
229
0
        if ((entry = (zip_hash_entry_t *)malloc(sizeof(zip_hash_entry_t))) == NULL) {
230
0
            zip_error_set(error, ZIP_ER_MEMORY, 0);
231
0
            return false;
232
0
        }
233
0
        entry->name = name;
234
0
        entry->next = hash->table[table_index];
235
0
        hash->table[table_index] = entry;
236
0
        entry->hash_value = hash_value;
237
0
        entry->orig_index = -1;
238
0
        hash->nentries++;
239
0
        if (hash->nentries > hash->table_size * HASH_MAX_FILL && hash->table_size < HASH_MAX_SIZE) {
240
0
            if (!hash_resize(hash, hash->table_size * 2, error)) {
241
0
                return false;
242
0
            }
243
0
        }
244
0
    }
245
246
0
    if (flags & ZIP_FL_UNCHANGED) {
247
0
        entry->orig_index = (zip_int64_t)index;
248
0
    }
249
0
    entry->current_index = (zip_int64_t)index;
250
251
0
    return true;
252
0
}
253
254
255
/* remove entry from hash, error if not found */
256
0
bool _zip_hash_delete(zip_hash_t *hash, const zip_uint8_t *name, zip_error_t *error) {
257
0
    zip_uint32_t hash_value, index;
258
0
    zip_hash_entry_t *entry, *previous;
259
260
0
    if (hash == NULL || name == NULL) {
261
0
        zip_error_set(error, ZIP_ER_INVAL, 0);
262
0
        return false;
263
0
    }
264
265
0
    if (hash->nentries > 0) {
266
0
        hash_value = hash_string(name);
267
0
        index = hash_value % hash->table_size;
268
0
        previous = NULL;
269
0
        entry = hash->table[index];
270
0
        while (entry) {
271
0
            if (entry->hash_value == hash_value && strcmp((const char *)name, (const char *)entry->name) == 0) {
272
0
                if (entry->orig_index == -1) {
273
0
                    if (previous) {
274
0
                        previous->next = entry->next;
275
0
                    }
276
0
                    else {
277
0
                        hash->table[index] = entry->next;
278
0
                    }
279
0
                    free(entry);
280
0
                    hash->nentries--;
281
0
                    if (hash->nentries < hash->table_size * HASH_MIN_FILL && hash->table_size > HASH_MIN_SIZE) {
282
0
                        if (!hash_resize(hash, hash->table_size / 2, error)) {
283
0
                            return false;
284
0
                        }
285
0
                    }
286
0
                }
287
0
                else {
288
0
                    entry->current_index = -1;
289
0
                }
290
0
                return true;
291
0
            }
292
0
            previous = entry;
293
0
            entry = entry->next;
294
0
        }
295
0
    }
296
297
0
    zip_error_set(error, ZIP_ER_NOENT, 0);
298
0
    return false;
299
0
}
300
301
302
/* find value for entry in hash, -1 if not found */
303
0
zip_int64_t _zip_hash_lookup(zip_hash_t *hash, const zip_uint8_t *name, zip_flags_t flags, zip_error_t *error) {
304
0
    zip_uint32_t hash_value, index;
305
0
    zip_hash_entry_t *entry;
306
307
0
    if (hash == NULL || name == NULL) {
308
0
        zip_error_set(error, ZIP_ER_INVAL, 0);
309
0
        return -1;
310
0
    }
311
312
0
    if (hash->nentries > 0) {
313
0
        hash_value = hash_string(name);
314
0
        index = hash_value % hash->table_size;
315
0
        for (entry = hash->table[index]; entry != NULL; entry = entry->next) {
316
0
            if (strcmp((const char *)name, (const char *)entry->name) == 0) {
317
0
                if (flags & ZIP_FL_UNCHANGED) {
318
0
                    if (entry->orig_index != -1) {
319
0
                        return entry->orig_index;
320
0
                    }
321
0
                }
322
0
                else {
323
0
                    if (entry->current_index != -1) {
324
0
                        return entry->current_index;
325
0
                    }
326
0
                }
327
0
                break;
328
0
            }
329
0
        }
330
0
    }
331
332
0
    zip_error_set(error, ZIP_ER_NOENT, 0);
333
0
    return -1;
334
0
}
335
336
337
0
bool _zip_hash_reserve_capacity(zip_hash_t *hash, zip_uint64_t capacity, zip_error_t *error) {
338
0
    zip_uint32_t new_size;
339
340
0
    if (capacity == 0) {
341
0
        return true;
342
0
    }
343
344
0
    new_size = size_for_capacity(capacity);
345
346
0
    if (new_size <= hash->table_size) {
347
0
        return true;
348
0
    }
349
350
0
    if (!hash_resize(hash, new_size, error)) {
351
0
        return false;
352
0
    }
353
354
0
    return true;
355
0
}
356
357
358
0
bool _zip_hash_revert(zip_hash_t *hash, zip_error_t *error) {
359
0
    zip_uint32_t i;
360
0
    zip_hash_entry_t *entry, *previous;
361
362
0
    for (i = 0; i < hash->table_size; i++) {
363
0
        previous = NULL;
364
0
        entry = hash->table[i];
365
0
        while (entry) {
366
0
            if (entry->orig_index == -1) {
367
0
                zip_hash_entry_t *p;
368
0
                if (previous) {
369
0
                    previous->next = entry->next;
370
0
                }
371
0
                else {
372
0
                    hash->table[i] = entry->next;
373
0
                }
374
0
                p = entry;
375
0
                entry = entry->next;
376
                /* previous does not change */
377
0
                free(p);
378
0
                hash->nentries--;
379
0
            }
380
0
            else {
381
0
                entry->current_index = entry->orig_index;
382
0
                previous = entry;
383
0
                entry = entry->next;
384
0
            }
385
0
        }
386
0
    }
387
388
0
    if (hash->nentries < hash->table_size * HASH_MIN_FILL && hash->table_size > HASH_MIN_SIZE) {
389
0
        zip_uint32_t new_size = hash->table_size / 2;
390
0
        while (hash->nentries < new_size * HASH_MIN_FILL && new_size > HASH_MIN_SIZE) {
391
0
            new_size /= 2;
392
0
        }
393
0
        if (!hash_resize(hash, new_size, error)) {
394
0
            return false;
395
0
        }
396
0
    }
397
398
0
    return true;
399
0
}