First iteration of hash table

include/ucore/htable.h

@@ -0,0 +1,214 @@
+#ifndef UC_HTABLE_H_
+#define UC_HTABLE_H_
+
+#include <stddef.h>
+
+/** Building block for hash table.
+ * The hash table is stored using a chained list of buckets.
+ * Nodes with different hash value can be stored in the same bucket.
+ *
+ *
+ * The hash table manages only the hash value, not the equality
+ * between nodes.
+ *
+ * It's up to the user to check for duplicate values
+ * before adding nodes if dublicates are not desired.
+ * 
+ * Finding a node must be done in a user specific way, 
+ * normally by iterating over all nodes with the desidred
+ * hash, and deciding in some other way whether it is the desidred
+ * node.
+ */
+
+/** Node the hashtable tracks.
+ * Will normally be embedded inside another struct
+ */
+struct UHNode {
+    //cached value of the hash
+    size_t hash;
+    //pointer to next in same bucket
+    struct UHNode *next;
+};
+
+/**
+ * The hash table struct
+ */
+struct UHTable {
+    size_t cnt_elements;
+    size_t cnt_buckets;
+    struct UHNode **buckets;
+};
+
+/**
+ * Initialize a hash table.
+ * @param table hash table to initialize
+ * @param buckets number of buckets
+ * @return 0 on success, errno if malloc fails or buckets == 0
+ */
+int uc_htable_init(struct UHTable *table, size_t buckets);
+
+/** 
+ * Frees resources of the hash table.
+ * @param table hash table to free (does not free @table itself
+ */
+void uc_htable_destroy(struct UHTable *table);
+
+
+/**
+ * @param table 
+ * @param hash find the bucket from this hash value
+ * @return the bucket number for the given hash
+ */
+static inline size_t uc_htable_bucket(const struct UHTable *table, size_t hash)
+{
+    return hash % table->cnt_buckets;
+}
+
+/**
+ * Get the first bucket node for the given hash.
+ * The returned node might not have the same hash, since different
+ * nodes can share the same bucket.
+ *
+ * @param table table
+ * @param hash hash
+ */
+static inline struct UHNode *uc_htable_first_bucket(const struct UHTable *table, size_t hash)
+{
+    size_t bucket = uc_htable_bucket(table, hash);
+
+    return table->buckets[bucket];
+}
+
+/**
+ * Get the next node in the bucket. 
+ * @return next node or NULL
+ */
+static inline struct UHNode *uc_htable_next_bucket(const struct UHNode *node)
+{
+    return node->next;
+}
+
+/**
+ * Get the first node that have the given hash
+ * @param table table
+ * @param hash hash
+ * @return first node with the given hash or NULL
+ */
+struct UHNode *uc_htable_first_hash(const struct UHTable *table, size_t hash);
+
+
+//internal helper
+struct UHNode *uc_htable_next_hash_hlp(struct UHNode *next, size_t hash);
+/**
+ * Get the next node with the same hash
+ * @param node previous node
+ * @return next node with the same hash as node or NULL
+ */
+static inline struct UHNode *uc_htable_next_hash(const struct UHNode *node)
+{
+    return uc_htable_next_hash_hlp(node->next, node->hash);
+}
+
+
+//internal helper
+struct UHNode *uc_htable_next_hlp(struct UHTable *table, size_t bucket);
+
+/** Get the first node in the hash table
+ *
+ * @param table table
+ * @return first node or NULL
+ */
+static inline struct UHNode *uc_htable_first(struct UHTable *table)
+{
+    return uc_htable_next_hlp(table, 0);
+}
+
+/** Get the next node in the hash table
+ *
+ * @param table table
+ * @param node previous node
+ * @return first node or NULL
+ */
+struct UHNode *uc_htable_next(struct UHTable *table, struct UHNode *node);
+
+/**
+ * Swap 2 hash tables.
+ *
+ * @param a first table
+ * @param b second table
+ */
+void uc_htable_swap(struct UHTable *a, struct UHTable *b);
+
+#define UC_HTABLE_FOREACH_BUCKET(table, node_iter, hash)\
+    for ((node_iter) = uc_htable_first_bucket((table), (hash));\
+         (node_iter) != NULL;\
+         (node_iter) = uc_htable_next_bucket((node_iter)))
+
+#define UC_HTABLE_FOREACH_HASH(table, node_iter, hash)\
+    for ((node_iter) = uc_htable_first_hash((table), (hash));\
+         (node_iter) != NULL;\
+         (node_iter) = uc_htable_next_hash((node_iter)))
+
+#define UC_HTABLE_FOREACH(table, node_iter, hash)\
+    for ((node_iter) = uc_htable_first((table));\
+         (node_iter) != NULL;\
+         (node_iter) = uc_htable_next((table), (node_iter)))
+
+
+/**
+ * Check if the given node pointer exists in the hash table
+ *
+ * @param table table
+ * @param node node to check for
+ * @return 0 if the node does not exist in table non-0 if it does
+ */
+int uc_htable_has_node(struct UHTable *table, struct UHNode *node);
+
+
+/**
+ *
+ * @return 0 if table is empty non-0 if it contains any nodes
+ */
+static inline int uc_htable_isempty(const struct UHTable *table)
+{
+    return table->cnt_elements == 0;
+}
+
+/**
+ * Get number of elements in the hash table.
+ *
+ * @rparam table table
+ * @return number of elements
+ */
+static inline size_t uc_htable_count(const struct UHTable *table)
+{
+    return table->cnt_elements;
+}
+
+/** Clears all nodes from the hash table, making it empty.
+ * No memory is released.
+ * @param table table to clear
+ */
+void uc_htable_clear(struct UHTable *table);
+
+/** Insert a new node.
+ * The new node pointer must exist as long as it is part of the 
+ * hash table. The hash table does not check for duplicates in any way.
+ *
+ * @param table table to insert into
+ * @param node new node to insert.
+ * @param hash hash value of the new node
+ */
+void uc_htable_insert(struct UHTable *table, struct UHNode *node, size_t hash);
+
+/** Resize the hash table. This changes the number of buckets, and re-inserts
+ * all nodes.
+ *
+ * @param table table to resize
+ * @param buckets new number of buckets, must be > 0
+ * @return 0 on success, errno if malloc fails or buckets == 0
+ */
+int uc_htable_resize(struct UHTable *table, size_t buckets);
+
+
+#endif

src/htable.c

@@ -0,0 +1,149 @@
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "ucore/htable.h"
+
+int uc_htable_init(struct UHTable *table, size_t buckets)
+{
+    if (buckets == 0) {
+        return EINVAL;
+    }
+
+    table->buckets = calloc(buckets, sizeof *table->buckets);
+    if (table->buckets == NULL) {
+        return ENOMEM; 
+    }
+
+    table->cnt_buckets = buckets;
+    table->cnt_elements = 0;
+
+    return 0;
+}
+
+void uc_htable_destroy(struct UHTable *table)
+{
+    free(table->buckets);
+    table->buckets = NULL;
+    table->cnt_elements = table->cnt_buckets = -1;
+}
+
+struct UHNode *uc_htable_first_hash(const struct UHTable *table, size_t hash)
+{
+    size_t bucket = uc_htable_bucket(table, hash);
+    struct UHNode *it = table->buckets[bucket];
+
+    while (it && it->hash != hash) {
+        it = it->next;
+    }
+
+    return it;
+}
+
+struct UHNode *uc_htable_next_hash_hlp(struct UHNode *next, size_t hash)
+{
+    while (next && next->hash != hash) {
+        next = next->next;
+    }
+
+    return next;
+}
+
+struct UHNode *uc_htable_next_hlp(struct UHTable *table, size_t bucket)
+{
+    size_t i;
+    struct UHNode *found = NULL;
+
+    for (i = bucket; i < table->cnt_buckets; i++) {
+        found = uc_htable_first_bucket(table, i);
+        if (found != NULL) {
+            break;
+        }
+    }
+    return found;
+}
+
+struct UHNode *uc_htable_next(struct UHTable *table, struct UHNode *node)
+{
+    struct UHNode *found;
+    
+    found = uc_htable_next_bucket(node);
+    if (found == NULL) {
+        found = uc_htable_next_hlp(table, node->hash + 1);
+    }
+
+    return found;
+}
+
+void uc_htable_swap(struct UHTable *a, struct UHTable *b)
+{
+    struct UHTable tmp;
+    
+    tmp = *a;
+    *a = *b;
+    *b = tmp;
+}
+
+int uc_htable_has_node(struct UHTable *table, struct UHNode *node)
+{
+    struct UHNode *iter;
+
+    UC_HTABLE_FOREACH_BUCKET(table, iter, node->hash) {
+        if (node == iter) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+void uc_htable_clear(struct UHTable *table)
+{
+    memset(table->buckets, 0 , sizeof *table->buckets * table->cnt_buckets);
+    table->cnt_elements = 0;
+}
+
+void uc_htable_insert(struct UHTable *table, struct UHNode *node, size_t hash)
+{
+    size_t bucket = uc_htable_bucket(table, hash);
+
+    node->next = table->buckets[bucket];
+    table->buckets[bucket] = node;
+    node->hash = hash;
+
+    table->cnt_elements++;
+}
+
+int uc_htable_resize(struct UHTable *table, size_t buckets)
+{
+    struct UHTable tmp_table;
+    int rc;
+    size_t h;
+
+    if (buckets == 0) {
+        return EINVAL;
+    }
+
+    rc = uc_htable_init(&tmp_table, buckets);
+    if (rc != 0) {
+        return rc;
+    }
+
+    for (h = 0; h < table->cnt_buckets; h++) {
+        struct UHNode *next;
+        struct UHNode *node;
+
+        for (node = uc_htable_first_bucket(table, h);
+                    node != NULL;
+                    node = next) {
+            next = node->next;
+            uc_htable_insert(&tmp_table, node, node->hash);
+        }
+    }
+
+    uc_htable_swap(&tmp_table, table);
+    uc_htable_destroy(&tmp_table);
+
+    return 0;
+}
+
+

test/test_runner.c

@@ -25,6 +25,7 @@ extern Suite *dbuf_suite(void);
 extern Suite *sprintb_suite(void);
 extern Suite *strv_suite(void);
 extern Suite *ratelimit_suite(void);
+extern Suite *htable_suite(void);
 
 static suite_func suites[] = {
     bitvec_suite,
@@ -44,6 +45,7 @@ static suite_func suites[] = {
     sprintb_suite,
     strv_suite,
     ratelimit_suite,
+    htable_suite,
     clock_suite,
     threadqueue_suite
 };