1 files changed, 477 insertions, 0 deletions
diff --git a/base/data-struct/hash.c b/base/data-struct/hash.c
new file mode 100644
index 0000000..db3dcd5
--- /dev/null
+++ b/base/data-struct/hash.c
@@ -0,0 +1,477 @@
+/*
+ * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
+ * Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of the device-mapper userspace tools.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "device_mapper/misc/dmlib.h"
+#include "base/memory/zalloc.h"
+#include "hash.h"
+
+struct dm_hash_node {
+	struct dm_hash_node *next;
+	void *data;
+	unsigned data_len;
+	unsigned keylen;
+	unsigned hash;
+	char key[0];
+};
+
+struct dm_hash_table {
+	unsigned num_nodes;
+	unsigned num_hint;
+	unsigned mask_slots;    /* (slots - 1) -> used as hash mask */
+	unsigned collisions;    /* Collissions of hash keys */
+	unsigned search;        /* How many keys were searched */
+	unsigned found;         /* How many nodes were found */
+	unsigned same_hash;     /* Was there a colision with same masked hash and len ? */
+	struct dm_hash_node **slots;
+};
+
+#if 0 /* TO BE REMOVED */
+static unsigned _hash(const void *key, unsigned len)
+{
+	/* Permutation of the Integers 0 through 255 */
+	static unsigned char _nums[] = {
+	1, 14, 110, 25, 97, 174, 132, 119, 138, 170, 125, 118, 27, 233, 140, 51,
+	87, 197, 177, 107, 234, 169, 56, 68, 30, 7, 173, 73, 188, 40, 36, 65,
+	49, 213, 104, 190, 57, 211, 148, 223, 48, 115, 15, 2, 67, 186, 210, 28,
+	12, 181, 103, 70, 22, 58, 75, 78, 183, 167, 238, 157, 124, 147, 172,
+	144,
+	176, 161, 141, 86, 60, 66, 128, 83, 156, 241, 79, 46, 168, 198, 41, 254,
+	178, 85, 253, 237, 250, 154, 133, 88, 35, 206, 95, 116, 252, 192, 54,
+	221,
+	102, 218, 255, 240, 82, 106, 158, 201, 61, 3, 89, 9, 42, 155, 159, 93,
+	166, 80, 50, 34, 175, 195, 100, 99, 26, 150, 16, 145, 4, 33, 8, 189,
+	121, 64, 77, 72, 208, 245, 130, 122, 143, 55, 105, 134, 29, 164, 185,
+	194,
+	193, 239, 101, 242, 5, 171, 126, 11, 74, 59, 137, 228, 108, 191, 232,
+	139,
+	6, 24, 81, 20, 127, 17, 91, 92, 251, 151, 225, 207, 21, 98, 113, 112,
+	84, 226, 18, 214, 199, 187, 13, 32, 94, 220, 224, 212, 247, 204, 196,
+	43,
+	249, 236, 45, 244, 111, 182, 153, 136, 129, 90, 217, 202, 19, 165, 231,
+	71,
+	230, 142, 96, 227, 62, 179, 246, 114, 162, 53, 160, 215, 205, 180, 47,
+	109,
+	44, 38, 31, 149, 135, 0, 216, 52, 63, 23, 37, 69, 39, 117, 146, 184,
+	163, 200, 222, 235, 248, 243, 219, 10, 152, 131, 123, 229, 203, 76, 120,
+	209
+	};
+
+	const uint8_t *str = key;
+	unsigned h = 0, g;
+	unsigned i;
+
+	for (i = 0; i < len; i++) {
+		h <<= 4;
+		h += _nums[*str++];
+		g = h & ((unsigned) 0xf << 16u);
+		if (g) {
+			h ^= g >> 16u;
+			h ^= g >> 5u;
+		}
+	}
+
+	return h;
+}
+
+/* In-kernel DM hashing, still lots of collisions */
+static unsigned _hash_in_kernel(const char *key, unsigned len)
+{
+	const unsigned char *str = (unsigned char *)key;
+	const unsigned hash_mult = 2654435387U;
+	unsigned hash = 0, i;
+
+	for (i = 0; i < len; ++i)
+		hash = (hash + str[i]) * hash_mult;
+
+	return hash;
+}
+#endif
+
+#undef get16bits
+#if (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
+#define get16bits(d) (*((const uint16_t *) (d)))
+#endif
+
+#if !defined (get16bits)
+#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)\
+                       +(uint32_t)(((const uint8_t *)(d))[0]) )
+#endif
+
+/*
+ * Adapted Bob Jenkins hash to read by 2 bytes if possible.
+ * https://secure.wikimedia.org/wikipedia/en/wiki/Jenkins_hash_function
+ *
+ * Reduces amount of hash collisions
+ */
+static unsigned _hash(const void *key, unsigned len)
+{
+	const uint8_t *str = (uint8_t*) key;
+	unsigned hash = 0, i;
+	unsigned sz = len / 2;
+
+	for(i = 0; i < sz; ++i) {
+		hash += get16bits(str + 2 * i);
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
+
+	if (len & 1) {
+		hash += str[len - 1];
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
+
+	hash += (hash << 3);
+	hash ^= (hash >> 11);
+	hash += (hash << 15);
+
+	return hash;
+}
+
+static struct dm_hash_node *_create_node(const void *key, unsigned len)
+{
+	struct dm_hash_node *n = malloc(sizeof(*n) + len);
+
+	if (n) {
+		memcpy(n->key, key, len);
+		n->keylen = len;
+	}
+
+	return n;
+}
+
+struct dm_hash_table *dm_hash_create(unsigned size_hint)
+{
+	size_t len;
+	unsigned new_size = 16u;
+	struct dm_hash_table *hc = zalloc(sizeof(*hc));
+
+	if (!hc) {
+		log_error("Failed to allocate memory for hash.");
+		return 0;
+	}
+
+	hc->num_hint = size_hint;
+
+	/* round size hint up to a power of two */
+	while (new_size < size_hint)
+		new_size = new_size << 1;
+
+	hc->mask_slots = new_size - 1;
+	len = sizeof(*(hc->slots)) * new_size;
+	if (!(hc->slots = zalloc(len))) {
+		free(hc);
+		log_error("Failed to allocate slots for hash.");
+		return 0;
+	}
+
+	return hc;
+}
+
+static void _free_nodes(struct dm_hash_table *t)
+{
+	struct dm_hash_node *c, *n;
+	unsigned i;
+
+#ifdef DEBUG
+	log_debug("Free hash hint:%d slots:%d nodes:%d (s:%d f:%d c:%d h:%d)",
+		  t->num_hint, t->mask_slots + 1, t->num_nodes,
+		  t->search, t->found, t->collisions, t->same_hash);
+#endif
+
+	if (!t->num_nodes)
+		return;
+
+	for (i = 0; i <= t->mask_slots; i++)
+		for (c = t->slots[i]; c; c = n) {
+			n = c->next;
+			free(c);
+		}
+}
+
+void dm_hash_destroy(struct dm_hash_table *t)
+{
+	_free_nodes(t);
+	free(t->slots);
+	free(t);
+}
+
+static struct dm_hash_node **_findh(struct dm_hash_table *t, const void *key,
+				    uint32_t len, unsigned hash)
+{
+	struct dm_hash_node **c;
+
+	++t->search;
+	for (c = &t->slots[hash & t->mask_slots]; *c; c = &((*c)->next)) {
+		if ((*c)->keylen == len && (*c)->hash == hash) {
+			if (!memcmp(key, (*c)->key, len)) {
+				++t->found;
+				break;
+			}
+			++t->same_hash;
+		}
+		++t->collisions;
+	}
+
+	return c;
+}
+
+static struct dm_hash_node **_find(struct dm_hash_table *t, const void *key,
+				   uint32_t len)
+{
+	return _findh(t, key, len, _hash(key, len));
+}
+
+void *dm_hash_lookup_binary(struct dm_hash_table *t, const void *key,
+			    uint32_t len)
+{
+	struct dm_hash_node **c = _find(t, key, len);
+
+	return *c ? (*c)->data : 0;
+}
+
+int dm_hash_insert_binary(struct dm_hash_table *t, const void *key,
+			  uint32_t len, void *data)
+{
+	unsigned hash = _hash(key, len);
+	struct dm_hash_node **c = _findh(t, key, len, hash);
+
+	if (*c)
+		(*c)->data = data;
+	else {
+		struct dm_hash_node *n = _create_node(key, len);
+
+		if (!n)
+			return 0;
+
+		n->data = data;
+		n->hash = hash;
+		n->next = 0;
+		*c = n;
+		t->num_nodes++;
+	}
+
+	return 1;
+}
+
+void dm_hash_remove_binary(struct dm_hash_table *t, const void *key,
+			uint32_t len)
+{
+	struct dm_hash_node **c = _find(t, key, len);
+
+	if (*c) {
+		struct dm_hash_node *old = *c;
+		*c = (*c)->next;
+		free(old);
+		t->num_nodes--;
+	}
+}
+
+void *dm_hash_lookup(struct dm_hash_table *t, const char *key)
+{
+	return dm_hash_lookup_binary(t, key, strlen(key) + 1);
+}
+
+int dm_hash_insert(struct dm_hash_table *t, const char *key, void *data)
+{
+	return dm_hash_insert_binary(t, key, strlen(key) + 1, data);
+}
+
+void dm_hash_remove(struct dm_hash_table *t, const char *key)
+{
+	dm_hash_remove_binary(t, key, strlen(key) + 1);
+}
+
+static struct dm_hash_node **_find_str_with_val(struct dm_hash_table *t,
+					        const void *key, const void *val,
+					        uint32_t len, uint32_t val_len)
+{
+	struct dm_hash_node **c;
+	unsigned h;
+       
+	h = _hash(key, len) & t->mask_slots;
+
+	for (c = &t->slots[h]; *c; c = &((*c)->next)) {
+		if ((*c)->keylen != len)
+			continue;
+
+		if (!memcmp(key, (*c)->key, len) && (*c)->data) {
+			if (((*c)->data_len == val_len) &&
+			    !memcmp(val, (*c)->data, val_len))
+				return c;
+		}
+	}
+
+	return NULL;
+}
+
+int dm_hash_insert_allow_multiple(struct dm_hash_table *t, const char *key,
+				  const void *val, uint32_t val_len)
+{
+	struct dm_hash_node *n;
+	struct dm_hash_node *first;
+	int len = strlen(key) + 1;
+	unsigned h;
+
+	n = _create_node(key, len);
+	if (!n)
+		return 0;
+
+	n->data = (void *)val;
+	n->data_len = val_len;
+
+	h = _hash(key, len) & t->mask_slots;
+
+	first = t->slots[h];
+
+	if (first)
+		n->next = first;
+	else
+		n->next = 0;
+	t->slots[h] = n;
+
+	t->num_nodes++;
+	return 1;
+}
+
+/*
+ * Look through multiple entries with the same key for one that has a
+ * matching val and return that.  If none have maching val, return NULL.
+ */
+void *dm_hash_lookup_with_val(struct dm_hash_table *t, const char *key,
+			      const void *val, uint32_t val_len)
+{
+	struct dm_hash_node **c;
+
+	c = _find_str_with_val(t, key, val, strlen(key) + 1, val_len);
+
+	return (c && *c) ? (*c)->data : 0;
+}
+
+/*
+ * Look through multiple entries with the same key for one that has a
+ * matching val and remove that.
+ */
+void dm_hash_remove_with_val(struct dm_hash_table *t, const char *key,
+			     const void *val, uint32_t val_len)
+{
+	struct dm_hash_node **c;
+
+	c = _find_str_with_val(t, key, val, strlen(key) + 1, val_len);
+
+	if (c && *c) {
+		struct dm_hash_node *old = *c;
+		*c = (*c)->next;
+		free(old);
+		t->num_nodes--;
+	}
+}
+
+/*
+ * Look up the value for a key and count how many
+ * entries have the same key.
+ *
+ * If no entries have key, return NULL and set count to 0.
+ *
+ * If one entry has the key, the function returns the val,
+ * and sets count to 1.
+ *
+ * If N entries have the key, the function returns the val
+ * from the first entry, and sets count to N.
+ */
+void *dm_hash_lookup_with_count(struct dm_hash_table *t, const char *key, int *count)
+{
+	struct dm_hash_node **c;
+	struct dm_hash_node **c1 = NULL;
+	uint32_t len = strlen(key) + 1;
+	unsigned h;
+
+	*count = 0;
+
+	h = _hash(key, len) & t->mask_slots;
+
+	for (c = &t->slots[h]; *c; c = &((*c)->next)) {
+		if ((*c)->keylen != len)
+			continue;
+
+		if (!memcmp(key, (*c)->key, len)) {
+			(*count)++;
+			if (!c1)
+				c1 = c;
+		}
+	}
+
+	if (!c1)
+		return NULL;
+	else
+		return *c1 ? (*c1)->data : 0;
+}
+
+unsigned dm_hash_get_num_entries(struct dm_hash_table *t)
+{
+	return t->num_nodes;
+}
+
+void dm_hash_iter(struct dm_hash_table *t, dm_hash_iterate_fn f)
+{
+	struct dm_hash_node *c, *n;
+	unsigned i;
+
+	for (i = 0; i <= t->mask_slots; i++)
+		for (c = t->slots[i]; c; c = n) {
+			n = c->next;
+			f(c->data);
+		}
+}
+
+void dm_hash_wipe(struct dm_hash_table *t)
+{
+	_free_nodes(t);
+	memset(t->slots, 0, sizeof(struct dm_hash_node *) * (t->mask_slots + 1));
+	t->num_nodes = t->collisions = t->search = t->same_hash = 0u;
+}
+
+char *dm_hash_get_key(struct dm_hash_table *t __attribute__((unused)),
+		      struct dm_hash_node *n)
+{
+	return n->key;
+}
+
+void *dm_hash_get_data(struct dm_hash_table *t __attribute__((unused)),
+		       struct dm_hash_node *n)
+{
+	return n->data;
+}
+
+static struct dm_hash_node *_next_slot(struct dm_hash_table *t, unsigned s)
+{
+	struct dm_hash_node *c = NULL;
+	unsigned i;
+
+	for (i = s; i <= t->mask_slots && !c; i++)
+		c = t->slots[i];
+
+	return c;
+}
+
+struct dm_hash_node *dm_hash_get_first(struct dm_hash_table *t)
+{
+	return _next_slot(t, 0);
+}
+
+struct dm_hash_node *dm_hash_get_next(struct dm_hash_table *t, struct dm_hash_node *n)
+{
+	return n->next ? n->next : _next_slot(t, (n->hash & t->mask_slots) + 1);
+}