1 files changed, 226 insertions, 0 deletions
diff --git a/ccan/htable/htable.h b/ccan/htable/htable.h
new file mode 100644
index 0000000..9845388
--- /dev/null
+++ b/ccan/htable/htable.h
@@ -0,0 +1,226 @@
+/* Licensed under LGPLv2+ - see LICENSE file for details */
+#ifndef CCAN_HTABLE_H
+#define CCAN_HTABLE_H
+#include "config.h"
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+/**
+ * struct htable - private definition of a htable.
+ *
+ * It's exposed here so you can put it in your structures and so we can
+ * supply inline functions.
+ */
+struct htable {
+	size_t (*rehash)(const void *elem, void *priv);
+	void *priv;
+	unsigned int bits;
+	size_t elems, deleted, max, max_with_deleted;
+	/* These are the bits which are the same in all pointers. */
+	uintptr_t common_mask, common_bits;
+	uintptr_t perfect_bit;
+	uintptr_t *table;
+};
+
+/**
+ * HTABLE_INITIALIZER - static initialization for a hash table.
+ * @name: name of this htable.
+ * @rehash: hash function to use for rehashing.
+ * @priv: private argument to @rehash function.
+ *
+ * This is useful for setting up static and global hash tables.
+ *
+ * Example:
+ *	// For simplicity's sake, say hash value is contents of elem.
+ *	static size_t rehash(const void *elem, void *unused)
+ *	{
+ *		(void)unused;
+ *		return *(size_t *)elem;
+ *	}
+ *	static struct htable ht = HTABLE_INITIALIZER(ht, rehash, NULL);
+ */
+#define HTABLE_INITIALIZER(name, rehash, priv)				\
+	{ rehash, priv, 0, 0, 0, 0, 0, -1, 0, 0, &name.perfect_bit }
+
+/**
+ * htable_init - initialize an empty hash table.
+ * @ht: the hash table to initialize
+ * @rehash: hash function to use for rehashing.
+ * @priv: private argument to @rehash function.
+ */
+void htable_init(struct htable *ht,
+		 size_t (*rehash)(const void *elem, void *priv), void *priv);
+
+/**
+ * htable_init_sized - initialize an empty hash table of given size.
+ * @ht: the hash table to initialize
+ * @rehash: hash function to use for rehashing.
+ * @priv: private argument to @rehash function.
+ * @size: the number of element.
+ *
+ * If this returns false, @ht is still usable, but may need to do reallocation
+ * upon an add.  If this returns true, it will not need to reallocate within
+ * @size htable_adds.
+ */
+bool htable_init_sized(struct htable *ht,
+		       size_t (*rehash)(const void *elem, void *priv),
+		       void *priv, size_t size);
+
+/**
+ * htable_clear - empty a hash table.
+ * @ht: the hash table to clear
+ *
+ * This doesn't do anything to any pointers left in it.
+ */
+void htable_clear(struct htable *ht);
+
+/**
+ * htable_copy - duplicate a hash table.
+ * @dst: the hash table to overwrite
+ * @src: the hash table to copy
+ *
+ * Only fails on out-of-memory.
+ *
+ * Equivalent to (but faster than):
+ *    if (!htable_init_sized(dst, src->rehash, src->priv, 1U << src->bits))
+ *	   return false;
+ *    v = htable_first(src, &i);
+ *    while (v) {
+ *		htable_add(dst, v);
+ *		v = htable_next(src, i);
+ *    }
+ *    return true;
+ */
+bool htable_copy(struct htable *dst, const struct htable *src);
+
+/**
+ * htable_rehash - use a hashtree's rehash function
+ * @elem: the argument to rehash()
+ *
+ */
+size_t htable_rehash(const void *elem);
+
+/**
+ * htable_add - add a pointer into a hash table.
+ * @ht: the htable
+ * @hash: the hash value of the object
+ * @p: the non-NULL pointer
+ *
+ * Also note that this can only fail due to allocation failure.  Otherwise, it
+ * returns true.
+ */
+bool htable_add(struct htable *ht, size_t hash, const void *p);
+
+/**
+ * htable_del - remove a pointer from a hash table
+ * @ht: the htable
+ * @hash: the hash value of the object
+ * @p: the pointer
+ *
+ * Returns true if the pointer was found (and deleted).
+ */
+bool htable_del(struct htable *ht, size_t hash, const void *p);
+
+/**
+ * struct htable_iter - iterator or htable_first or htable_firstval etc.
+ *
+ * This refers to a location inside the hashtable.
+ */
+struct htable_iter {
+	size_t off;
+};
+
+/**
+ * htable_firstval - find a candidate for a given hash value
+ * @htable: the hashtable
+ * @i: the struct htable_iter to initialize
+ * @hash: the hash value
+ *
+ * You'll need to check the value is what you want; returns NULL if none.
+ * See Also:
+ *	htable_delval()
+ */
+void *htable_firstval(const struct htable *htable,
+		      struct htable_iter *i, size_t hash);
+
+/**
+ * htable_nextval - find another candidate for a given hash value
+ * @htable: the hashtable
+ * @i: the struct htable_iter to initialize
+ * @hash: the hash value
+ *
+ * You'll need to check the value is what you want; returns NULL if no more.
+ */
+void *htable_nextval(const struct htable *htable,
+		     struct htable_iter *i, size_t hash);
+
+/**
+ * htable_get - find an entry in the hash table
+ * @ht: the hashtable
+ * @h: the hash value of the entry
+ * @cmp: the comparison function
+ * @ptr: the pointer to hand to the comparison function.
+ *
+ * Convenient inline wrapper for htable_firstval/htable_nextval loop.
+ */
+static inline void *htable_get(const struct htable *ht,
+			       size_t h,
+			       bool (*cmp)(const void *candidate, void *ptr),
+			       const void *ptr)
+{
+	struct htable_iter i;
+	void *c;
+
+	for (c = htable_firstval(ht,&i,h); c; c = htable_nextval(ht,&i,h)) {
+		if (cmp(c, (void *)ptr))
+			return c;
+	}
+	return NULL;
+}
+
+/**
+ * htable_first - find an entry in the hash table
+ * @ht: the hashtable
+ * @i: the struct htable_iter to initialize
+ *
+ * Get an entry in the hashtable; NULL if empty.
+ */
+void *htable_first(const struct htable *htable, struct htable_iter *i);
+
+/**
+ * htable_next - find another entry in the hash table
+ * @ht: the hashtable
+ * @i: the struct htable_iter to use
+ *
+ * Get another entry in the hashtable; NULL if all done.
+ * This is usually used after htable_first or prior non-NULL htable_next.
+ */
+void *htable_next(const struct htable *htable, struct htable_iter *i);
+
+/**
+ * htable_prev - find the previous entry in the hash table
+ * @ht: the hashtable
+ * @i: the struct htable_iter to use
+ *
+ * Get previous entry in the hashtable; NULL if all done.
+ *
+ * "previous" here only means the item that would have been returned by
+ * htable_next() before the item it returned most recently.
+ *
+ * This is usually used in the middle of (or after) a htable_next iteration and
+ * to "unwind" actions taken.
+ */
+void *htable_prev(const struct htable *htable, struct htable_iter *i);
+
+/**
+ * htable_delval - remove an iterated pointer from a hash table
+ * @ht: the htable
+ * @i: the htable_iter
+ *
+ * Usually used to delete a hash entry after it has been found with
+ * htable_firstval etc.
+ */
+void htable_delval(struct htable *ht, struct htable_iter *i);
+
+#endif /* CCAN_HTABLE_H */