+++ /dev/null
-/* hash - implement simple hashing table where the keys are memory blocks.
- Copyright (C) 1994-2024 Free Software Foundation, Inc.
- Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, October 1994.
-
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <https://www.gnu.org/licenses/>. */
-
-#include <config.h>
-
-/* Specification. */
-#include "mem-hash-map.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <limits.h>
-#include <sys/types.h>
-
-/* Since this simple implementation of hash tables allows only insertion, no
- removal of entries, the right data structure for the memory holding all keys
- is an obstack. */
-#include "obstack.h"
-
-/* Use checked memory allocation. */
-#include "xalloc.h"
-
-#define obstack_chunk_alloc xmalloc
-#define obstack_chunk_free free
-
-
-typedef struct hash_entry
-{
- unsigned long used; /* Hash code of the key, or 0 for an unused entry. */
- const void *key; /* Key. */
- size_t keylen;
- void *data; /* Value. */
- struct hash_entry *next;
-}
-hash_entry;
-
-
-/* Given an odd CANDIDATE > 1, return true if it is a prime number. */
-static int
-is_prime (unsigned long int candidate)
-{
- /* No even number and none less than 10 will be passed here. */
- unsigned long int divn = 3;
- unsigned long int sq = divn * divn;
-
- while (sq < candidate && candidate % divn != 0)
- {
- ++divn;
- sq += 4 * divn;
- ++divn;
- }
-
- return candidate % divn != 0;
-}
-
-
-/* Given SEED > 1, return the smallest odd prime number >= SEED. */
-unsigned long
-next_prime (unsigned long int seed)
-{
- /* Make it definitely odd. */
- seed |= 1;
-
- while (!is_prime (seed))
- seed += 2;
-
- return seed;
-}
-
-
-/* Initialize a hash table. INIT_SIZE > 1 is the initial number of available
- entries.
- Return 0 always. */
-int
-hash_init (hash_table *htab, unsigned long int init_size)
-{
- /* We need the size to be a prime. */
- init_size = next_prime (init_size);
-
- /* Initialize the data structure. */
- htab->size = init_size;
- htab->filled = 0;
- htab->first = NULL;
- htab->table = XCALLOC (init_size + 1, hash_entry);
-
- obstack_init (&htab->mem_pool);
-
- return 0;
-}
-
-
-/* Delete a hash table's contents.
- Return 0 always. */
-int
-hash_destroy (hash_table *htab)
-{
- free (htab->table);
- obstack_free (&htab->mem_pool, NULL);
- return 0;
-}
-
-
-/* Compute a hash code for a key consisting of KEYLEN bytes starting at KEY
- in memory. */
-static unsigned long
-compute_hashval (const void *key, size_t keylen)
-{
- size_t cnt;
- unsigned long int hval;
-
- /* Compute the hash value for the given string. The algorithm
- is taken from [Aho,Sethi,Ullman], fixed according to
- https://haible.de/bruno/hashfunc.html. */
- cnt = 0;
- hval = keylen;
- while (cnt < keylen)
- {
- hval = (hval << 9) | (hval >> (sizeof (unsigned long) * CHAR_BIT - 9));
- hval += (unsigned long int) *(((const char *) key) + cnt++);
- }
- return hval != 0 ? hval : ~((unsigned long) 0);
-}
-
-
-/* References:
- [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
- [Knuth] The Art of Computer Programming, part3 (6.4) */
-
-/* Look up a given key in the hash table.
- Return the index of the entry, if present, or otherwise the index a free
- entry where it could be inserted. */
-static size_t
-lookup (const hash_table *htab,
- const void *key, size_t keylen,
- unsigned long int hval)
-{
- unsigned long int hash;
- size_t idx;
- hash_entry *table = htab->table;
-
- /* First hash function: simply take the modul but prevent zero. */
- hash = 1 + hval % htab->size;
-
- idx = hash;
-
- if (table[idx].used)
- {
- if (table[idx].used == hval && table[idx].keylen == keylen
- && memcmp (table[idx].key, key, keylen) == 0)
- return idx;
-
- /* Second hash function as suggested in [Knuth]. */
- hash = 1 + hval % (htab->size - 2);
-
- do
- {
- if (idx <= hash)
- idx = htab->size + idx - hash;
- else
- idx -= hash;
-
- /* If entry is found use it. */
- if (table[idx].used == hval && table[idx].keylen == keylen
- && memcmp (table[idx].key, key, keylen) == 0)
- return idx;
- }
- while (table[idx].used);
- }
- return idx;
-}
-
-
-/* Look up the value of a key in the given table.
- If found, return 0 and set *RESULT to it. Otherwise return -1. */
-int
-hash_find_entry (const hash_table *htab, const void *key, size_t keylen,
- void **result)
-{
- hash_entry *table = htab->table;
- size_t idx = lookup (htab, key, keylen, compute_hashval (key, keylen));
-
- if (table[idx].used == 0)
- return -1;
-
- *result = table[idx].data;
- return 0;
-}
-
-
-/* Insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table at index IDX.
- HVAL is the key's hash code. IDX depends on it. The table entry at index
- IDX is known to be unused. */
-static void
-insert_entry_2 (hash_table *htab,
- const void *key, size_t keylen,
- unsigned long int hval, size_t idx, void *data)
-{
- hash_entry *table = htab->table;
-
- table[idx].used = hval;
- table[idx].key = key;
- table[idx].keylen = keylen;
- table[idx].data = data;
-
- /* List the new value in the list. */
- if (htab->first == NULL)
- {
- table[idx].next = &table[idx];
- htab->first = &table[idx];
- }
- else
- {
- table[idx].next = htab->first->next;
- htab->first->next = &table[idx];
- htab->first = &table[idx];
- }
-
- ++htab->filled;
-}
-
-
-/* Grow the hash table. */
-static void
-resize (hash_table *htab)
-{
- unsigned long int old_size = htab->size;
- hash_entry *table = htab->table;
- size_t idx;
-
- htab->size = next_prime (htab->size * 2);
- htab->filled = 0;
- htab->first = NULL;
- htab->table = XCALLOC (1 + htab->size, hash_entry);
-
- for (idx = 1; idx <= old_size; ++idx)
- if (table[idx].used)
- insert_entry_2 (htab, table[idx].key, table[idx].keylen,
- table[idx].used,
- lookup (htab, table[idx].key, table[idx].keylen,
- table[idx].used),
- table[idx].data);
-
- free (table);
-}
-
-
-/* Try to insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
- Return non-NULL (more precisely, the address of the KEY inside the table's
- memory pool) if successful, or NULL if there is already an entry with the
- given key. */
-const void *
-hash_insert_entry (hash_table *htab,
- const void *key, size_t keylen,
- void *data)
-{
- unsigned long int hval = compute_hashval (key, keylen);
- hash_entry *table = htab->table;
- size_t idx = lookup (htab, key, keylen, hval);
-
- if (table[idx].used)
- /* We don't want to overwrite the old value. */
- return NULL;
- else
- {
- /* An empty bucket has been found. */
- void *keycopy = obstack_copy (&htab->mem_pool, key, keylen);
- insert_entry_2 (htab, keycopy, keylen, hval, idx, data);
- if (100 * htab->filled > 75 * htab->size)
- /* Table is filled more than 75%. Resize the table. */
- resize (htab);
- return keycopy;
- }
-}
-
-
-/* Insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
- Return 0. */
-int
-hash_set_value (hash_table *htab,
- const void *key, size_t keylen,
- void *data)
-{
- unsigned long int hval = compute_hashval (key, keylen);
- hash_entry *table = htab->table;
- size_t idx = lookup (htab, key, keylen, hval);
-
- if (table[idx].used)
- {
- /* Overwrite the old value. */
- table[idx].data = data;
- return 0;
- }
- else
- {
- /* An empty bucket has been found. */
- void *keycopy = obstack_copy (&htab->mem_pool, key, keylen);
- insert_entry_2 (htab, keycopy, keylen, hval, idx, data);
- if (100 * htab->filled > 75 * htab->size)
- /* Table is filled more than 75%. Resize the table. */
- resize (htab);
- return 0;
- }
-}
-
-
-/* Steps *PTR forward to the next used entry in the given hash table. *PTR
- should be initially set to NULL. Store information about the next entry
- in *KEY, *KEYLEN, *DATA.
- Return 0 normally, -1 when the whole hash table has been traversed. */
-int
-hash_iterate (hash_table *htab, void **ptr, const void **key, size_t *keylen,
- void **data)
-{
- hash_entry *curr;
-
- if (*ptr == NULL)
- {
- if (htab->first == NULL)
- return -1;
- curr = htab->first;
- }
- else
- {
- if (*ptr == htab->first)
- return -1;
- curr = (hash_entry *) *ptr;
- }
- curr = curr->next;
- *ptr = (void *) curr;
-
- *key = curr->key;
- *keylen = curr->keylen;
- *data = curr->data;
- return 0;
-}
-
-
-/* Steps *PTR forward to the next used entry in the given hash table. *PTR
- should be initially set to NULL. Store information about the next entry
- in *KEY, *KEYLEN, *DATAP. *DATAP is set to point to the storage of the
- value; modifying **DATAP will modify the value of the entry.
- Return 0 normally, -1 when the whole hash table has been traversed. */
-int
-hash_iterate_modify (hash_table *htab, void **ptr,
- const void **key, size_t *keylen,
- void ***datap)
-{
- hash_entry *curr;
-
- if (*ptr == NULL)
- {
- if (htab->first == NULL)
- return -1;
- curr = htab->first;
- }
- else
- {
- if (*ptr == htab->first)
- return -1;
- curr = (hash_entry *) *ptr;
- }
- curr = curr->next;
- *ptr = (void *) curr;
-
- *key = curr->key;
- *keylen = curr->keylen;
- *datap = &curr->data;
- return 0;
-}
+++ /dev/null
-/* Copyright (C) 1995-2024 Free Software Foundation, Inc.
-
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <https://www.gnu.org/licenses/>. */
-
-#ifndef _HASH_H
-#define _HASH_H
-
-#include "obstack.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct hash_entry;
-
-typedef struct hash_table
-{
- unsigned long int size; /* Number of allocated entries. */
- unsigned long int filled; /* Number of used entries. */
- struct hash_entry *first; /* Pointer to head of list of entries. */
- struct hash_entry *table; /* Pointer to array of entries. */
- struct obstack mem_pool; /* Memory pool holding the keys. */
-}
-hash_table;
-
-/* Initialize a hash table. INIT_SIZE > 1 is the initial number of available
- entries.
- Return 0 always. */
-extern int hash_init (hash_table *htab, unsigned long int init_size);
-
-/* Delete a hash table's contents.
- Return 0 always. */
-extern int hash_destroy (hash_table *htab);
-
-/* Look up the value of a key in the given table.
- If found, return 0 and set *RESULT to it. Otherwise return -1. */
-extern int hash_find_entry (const hash_table *htab,
- const void *key, size_t keylen,
- void **result);
-
-/* Try to insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
- Return non-NULL (more precisely, the address of the KEY inside the table's
- memory pool) if successful, or NULL if there is already an entry with the
- given key. */
-extern const void * hash_insert_entry (hash_table *htab,
- const void *key, size_t keylen,
- void *data);
-
-/* Insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
- Return 0. */
-extern int hash_set_value (hash_table *htab,
- const void *key, size_t keylen,
- void *data);
-
-/* Steps *PTR forward to the next used entry in the given hash table. *PTR
- should be initially set to NULL. Store information about the next entry
- in *KEY, *KEYLEN, *DATA.
- Return 0 normally, -1 when the whole hash table has been traversed. */
-extern int hash_iterate (hash_table *htab, void **ptr,
- const void **key, size_t *keylen,
- void **data);
-
-/* Steps *PTR forward to the next used entry in the given hash table. *PTR
- should be initially set to NULL. Store information about the next entry
- in *KEY, *KEYLEN, *DATAP. *DATAP is set to point to the storage of the
- value; modifying **DATAP will modify the value of the entry.
- Return 0 normally, -1 when the whole hash table has been traversed. */
-extern int hash_iterate_modify (hash_table *htab, void **ptr,
- const void **key, size_t *keylen,
- void ***datap);
-
-/* Given SEED > 1, return the smallest odd prime number >= SEED. */
-extern unsigned long int next_prime (unsigned long int seed);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* not _HASH_H */
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