1 files changed, 98 insertions, 0 deletions
diff --git a/hashmap.h b/hashmap.h
new file mode 100644
index 0000000000..ab7958ae33
--- /dev/null
+++ b/hashmap.h
@@ -0,0 +1,98 @@
+#ifndef HASHMAP_H
+#define HASHMAP_H
+
+/*
+ * Generic implementation of hash-based key-value mappings.
+ * See Documentation/technical/api-hashmap.txt.
+ */
+
+/* FNV-1 functions */
+
+extern unsigned int strhash(const char *buf);
+extern unsigned int strihash(const char *buf);
+extern unsigned int memhash(const void *buf, size_t len);
+extern unsigned int memihash(const void *buf, size_t len);
+
+static inline unsigned int sha1hash(const unsigned char *sha1)
+{
+	/*
+	 * Equivalent to 'return *(unsigned int *)sha1;', but safe on
+	 * platforms that don't support unaligned reads.
+	 */
+	unsigned int hash;
+	memcpy(&hash, sha1, sizeof(hash));
+	return hash;
+}
+
+/* data structures */
+
+struct hashmap_entry {
+	struct hashmap_entry *next;
+	unsigned int hash;
+};
+
+typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
+		const void *keydata);
+
+struct hashmap {
+	struct hashmap_entry **table;
+	hashmap_cmp_fn cmpfn;
+	unsigned int size, tablesize, grow_at, shrink_at;
+};
+
+struct hashmap_iter {
+	struct hashmap *map;
+	struct hashmap_entry *next;
+	unsigned int tablepos;
+};
+
+/* hashmap functions */
+
+extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
+		size_t initial_size);
+extern void hashmap_free(struct hashmap *map, int free_entries);
+
+/* hashmap_entry functions */
+
+static inline void hashmap_entry_init(void *entry, unsigned int hash)
+{
+	struct hashmap_entry *e = entry;
+	e->hash = hash;
+	e->next = NULL;
+}
+extern void *hashmap_get(const struct hashmap *map, const void *key,
+		const void *keydata);
+extern void *hashmap_get_next(const struct hashmap *map, const void *entry);
+extern void hashmap_add(struct hashmap *map, void *entry);
+extern void *hashmap_put(struct hashmap *map, void *entry);
+extern void *hashmap_remove(struct hashmap *map, const void *key,
+		const void *keydata);
+
+static inline void *hashmap_get_from_hash(const struct hashmap *map,
+		unsigned int hash, const void *keydata)
+{
+	struct hashmap_entry key;
+	hashmap_entry_init(&key, hash);
+	return hashmap_get(map, &key, keydata);
+}
+
+/* hashmap_iter functions */
+
+extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
+extern void *hashmap_iter_next(struct hashmap_iter *iter);
+static inline void *hashmap_iter_first(struct hashmap *map,
+		struct hashmap_iter *iter)
+{
+	hashmap_iter_init(map, iter);
+	return hashmap_iter_next(iter);
+}
+
+/* string interning */
+
+extern const void *memintern(const void *data, size_t len);
+static inline const char *strintern(const char *string)
+{
+	return memintern(string, strlen(string));
+}
+
+#endif