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authorJinkun Jang <jinkun.jang@samsung.com>2013-03-12 15:14:36 +0900
committerJinkun Jang <jinkun.jang@samsung.com>2013-03-12 15:14:36 +0900
commit993d65531741fccf26fc10fc5789a5c9fca8c5ae (patch)
tree996be9095a97ff2aac0d98963b6044d47a0ec60c /hashtbl.c
parent65c26d26fb72cec0d43d199c72ed27513d17f4c9 (diff)
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+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 1996-2009 The NASM Authors - All Rights Reserved
+ * See the file AUTHORS included with the NASM distribution for
+ * the specific copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "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 COPYRIGHT OWNER OR
+ * CONTRIBUTORS 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * hashtbl.c
+ *
+ * Efficient dictionary hash table class.
+ */
+
+#include "compiler.h"
+
+#include <inttypes.h>
+#include <string.h>
+#include "nasm.h"
+#include "hashtbl.h"
+
+#define HASH_MAX_LOAD 2 /* Higher = more memory-efficient, slower */
+
+#define hash_calc(key) crc64(CRC64_INIT, (key))
+#define hash_calci(key) crc64i(CRC64_INIT, (key))
+#define hash_max_load(size) ((size) * (HASH_MAX_LOAD - 1) / HASH_MAX_LOAD)
+#define hash_expand(size) ((size) << 1)
+#define hash_mask(size) ((size) - 1)
+#define hash_pos(hash, mask) ((hash) & (mask))
+#define hash_inc(hash, mask) ((((hash) >> 32) & (mask)) | 1) /* always odd */
+#define hash_pos_next(pos, inc, mask) (((pos) + (inc)) & (mask))
+
+static struct hash_tbl_node *alloc_table(size_t newsize)
+{
+ size_t bytes = newsize * sizeof(struct hash_tbl_node);
+ return nasm_zalloc(bytes);
+}
+
+void hash_init(struct hash_table *head, size_t size)
+{
+ nasm_assert(is_power2(size));
+ head->table = alloc_table(size);
+ head->load = 0;
+ head->size = size;
+ head->max_load = hash_max_load(size);
+}
+
+/*
+ * Find an entry in a hash table.
+ *
+ * On failure, if "insert" is non-NULL, store data in that structure
+ * which can be used to insert that node using hash_add().
+ *
+ * WARNING: this data is only valid until the very next call of
+ * hash_add(); it cannot be "saved" to a later date.
+ *
+ * On success, return a pointer to the "data" element of the hash
+ * structure.
+ */
+void **hash_find(struct hash_table *head, const char *key,
+ struct hash_insert *insert)
+{
+ struct hash_tbl_node *np;
+ struct hash_tbl_node *tbl = head->table;
+ uint64_t hash = hash_calc(key);
+ size_t mask = hash_mask(head->size);
+ size_t pos = hash_pos(hash, mask);
+ size_t inc = hash_inc(hash, mask);
+
+ while ((np = &tbl[pos])->key) {
+ if (hash == np->hash && !strcmp(key, np->key))
+ return &np->data;
+ pos = hash_pos_next(pos, inc, mask);
+ }
+
+ /* Not found. Store info for insert if requested. */
+ if (insert) {
+ insert->head = head;
+ insert->hash = hash;
+ insert->where = np;
+ }
+ return NULL;
+}
+
+/*
+ * Same as hash_find, but for case-insensitive hashing.
+ */
+void **hash_findi(struct hash_table *head, const char *key,
+ struct hash_insert *insert)
+{
+ struct hash_tbl_node *np;
+ struct hash_tbl_node *tbl = head->table;
+ uint64_t hash = hash_calci(key);
+ size_t mask = hash_mask(head->size);
+ size_t pos = hash_pos(hash, mask);
+ size_t inc = hash_inc(hash, mask);
+
+ while ((np = &tbl[pos])->key) {
+ if (hash == np->hash && !nasm_stricmp(key, np->key))
+ return &np->data;
+ pos = hash_pos_next(pos, inc, mask);
+ }
+
+ /* Not found. Store info for insert if requested. */
+ if (insert) {
+ insert->head = head;
+ insert->hash = hash;
+ insert->where = np;
+ }
+ return NULL;
+}
+
+/*
+ * Insert node. Return a pointer to the "data" element of the newly
+ * created hash node.
+ */
+void **hash_add(struct hash_insert *insert, const char *key, void *data)
+{
+ struct hash_table *head = insert->head;
+ struct hash_tbl_node *np = insert->where;
+
+ /*
+ * Insert node. We can always do this, even if we need to
+ * rebalance immediately after.
+ */
+ np->hash = insert->hash;
+ np->key = key;
+ np->data = data;
+
+ if (++head->load > head->max_load) {
+ /* Need to expand the table */
+ size_t newsize = hash_expand(head->size);
+ struct hash_tbl_node *newtbl = alloc_table(newsize);
+ size_t mask = hash_mask(newsize);
+
+ if (head->table) {
+ struct hash_tbl_node *op, *xp;
+ size_t i;
+
+ /* Rebalance all the entries */
+ for (i = 0, op = head->table; i < head->size; i++, op++) {
+ if (op->key) {
+ size_t pos = hash_pos(op->hash, mask);
+ size_t inc = hash_inc(op->hash, mask);
+
+ while ((xp = &newtbl[pos])->key)
+ pos = hash_pos_next(pos, inc, mask);
+
+ *xp = *op;
+ if (op == np)
+ np = xp;
+ }
+ }
+ nasm_free(head->table);
+ }
+
+ head->table = newtbl;
+ head->size = newsize;
+ head->max_load = hash_max_load(newsize);
+ }
+
+ return &np->data;
+}
+
+/*
+ * Iterate over all members of a hash set. For the first call,
+ * iterator should be initialized to NULL. Returns the data pointer,
+ * or NULL on failure.
+ */
+void *hash_iterate(const struct hash_table *head,
+ struct hash_tbl_node **iterator,
+ const char **key)
+{
+ struct hash_tbl_node *np = *iterator;
+ struct hash_tbl_node *ep = head->table + head->size;
+
+ if (!np) {
+ np = head->table;
+ if (!np)
+ return NULL; /* Uninitialized table */
+ }
+
+ while (np < ep) {
+ if (np->key) {
+ *iterator = np + 1;
+ if (key)
+ *key = np->key;
+ return np->data;
+ }
+ np++;
+ }
+
+ *iterator = NULL;
+ if (key)
+ *key = NULL;
+ return NULL;
+}
+
+/*
+ * Free the hash itself. Doesn't free the data elements; use
+ * hash_iterate() to do that first, if needed.
+ */
+void hash_free(struct hash_table *head)
+{
+ void *p = head->table;
+ head->table = NULL;
+ nasm_free(p);
+}