/* zip_hash.c -- hash table string -> uint64 Copyright (C) 2015-2016 Dieter Baron and Thomas Klausner This file is part of libzip, a library to manipulate ZIP archives. The authors can be contacted at <libzip@nih.at> Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The names of the authors may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <stdlib.h> #include <string.h> #include "zipint.h" struct zip_hash_entry { const zip_uint8_t *name; zip_int64_t orig_index; zip_int64_t current_index; struct zip_hash_entry *next; }; typedef struct zip_hash_entry zip_hash_entry_t; struct zip_hash { zip_uint16_t table_size; zip_hash_entry_t **table; }; zip_hash_t * _zip_hash_new(zip_uint16_t table_size, zip_error_t *error) { zip_hash_t *hash; if (table_size == 0) { zip_error_set(error, ZIP_ER_INTERNAL, 0); return NULL; } if ((hash=(zip_hash_t *)malloc(sizeof(zip_hash_t))) == NULL) { zip_error_set(error, ZIP_ER_MEMORY, 0); return NULL; } hash->table_size = table_size; if ((hash->table=(zip_hash_entry_t**)calloc(table_size, sizeof(zip_hash_entry_t *))) == NULL) { free(hash); zip_error_set(error, ZIP_ER_MEMORY, 0); return NULL; } return hash; } static void _free_list(zip_hash_entry_t *entry) { zip_hash_entry_t *next; do { next = entry->next; free(entry); entry = next; } while (entry != NULL); } void _zip_hash_free(zip_hash_t *hash) { zip_uint16_t i; if (hash == NULL) { return; } for (i=0; i<hash->table_size; i++) { if (hash->table[i] != NULL) { _free_list(hash->table[i]); } } free(hash->table); free(hash); } static zip_uint16_t _hash_string(const zip_uint8_t *name, zip_uint16_t size) { #define HASH_MULTIPLIER 33 zip_uint16_t value = 5381; if (name == NULL) return 0; while (*name != 0) { value = (zip_uint16_t)(((value * HASH_MULTIPLIER) + (zip_uint8_t)*name) % size); name++; } return value; } /* insert into hash, return error on existence or memory issues */ 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) { zip_uint16_t hash_value; zip_hash_entry_t *entry; if (hash == NULL || name == NULL || index > ZIP_INT64_MAX) { zip_error_set(error, ZIP_ER_INVAL, 0); return false; } hash_value = _hash_string(name, hash->table_size); for (entry = hash->table[hash_value]; entry != NULL; entry = entry->next) { if (strcmp((const char *)name, (const char *)entry->name) == 0) { if (((flags & ZIP_FL_UNCHANGED) && entry->orig_index != -1) || entry->current_index != -1) { zip_error_set(error, ZIP_ER_EXISTS, 0); return false; } else { break; } } } if (entry == NULL) { if ((entry=(zip_hash_entry_t *)malloc(sizeof(zip_hash_entry_t))) == NULL) { zip_error_set(error, ZIP_ER_MEMORY, 0); return false; } entry->name = name; entry->next = hash->table[hash_value]; hash->table[hash_value] = entry; entry->orig_index = -1; } if (flags & ZIP_FL_UNCHANGED) { entry->orig_index = (zip_int64_t)index; } entry->current_index = (zip_int64_t)index; return true; } /* remove entry from hash, error if not found */ bool _zip_hash_delete(zip_hash_t *hash, const zip_uint8_t *name, zip_error_t *error) { zip_uint16_t hash_value; zip_hash_entry_t *entry, *previous; if (hash == NULL || name == NULL) { zip_error_set(error, ZIP_ER_INVAL, 0); return false; } hash_value = _hash_string(name, hash->table_size); previous = NULL; entry = hash->table[hash_value]; while (entry) { if (strcmp((const char *)name, (const char *)entry->name) == 0) { if (entry->orig_index == -1) { if (previous) { previous->next = entry->next; } else { hash->table[hash_value] = entry->next; } free(entry); } else { entry->current_index = -1; } return true; } previous = entry; entry = entry->next; }; zip_error_set(error, ZIP_ER_NOENT, 0); return false; } /* find value for entry in hash, -1 if not found */ zip_int64_t _zip_hash_lookup(zip_hash_t *hash, const zip_uint8_t *name, zip_flags_t flags, zip_error_t *error) { zip_uint16_t hash_value; zip_hash_entry_t *entry; if (hash == NULL || name == NULL) { zip_error_set(error, ZIP_ER_INVAL, 0); return -1; } hash_value = _hash_string(name, hash->table_size); for (entry = hash->table[hash_value]; entry != NULL; entry = entry->next) { if (strcmp((const char *)name, (const char *)entry->name) == 0) { if (flags & ZIP_FL_UNCHANGED) { if (entry->orig_index != -1) { return entry->orig_index; } } else { if (entry->current_index != -1) { return entry->current_index; } } break; } } zip_error_set(error, ZIP_ER_NOENT, 0); return -1; } void _zip_hash_revert(zip_hash_t *hash) { zip_uint16_t i; zip_hash_entry_t *entry, *previous; for (i = 0; i < hash->table_size; i++) { previous = NULL; entry = hash->table[i]; while (entry) { if (entry->orig_index == -1) { zip_hash_entry_t *p; if (previous) { previous->next = entry->next; } else { hash->table[i] = entry->next; } p = entry; entry = entry->next; /* previous does not change */ free(p); } else { entry->current_index = entry->orig_index; previous = entry; entry = entry->next; } } } }