redblack.c include/dns/redblack.h

Initial (committed) implementation of red/black tree of trees.

Makefile.in:
	add redblack.o to libdns.

lib/dns/Makefile.in

@@ -12,7 +12,8 @@ CINCLUDES =	-I${srcdir}/../isc/unix/include \
 CDEFINES =
 CWARNINGS =
 
-OBJS =		name.o rdatalist.o rdataset.o result.o version.o rdata.o
+OBJS =		name.o rdata.o rdatalist.o rdataset.o \
+		redblack.o result.o version.o
 
 SUBDIRS =	include
 TARGETS =	timestamp

lib/dns/include/dns/rbt.h

@@ -0,0 +1,115 @@
+#include <isc/result.h>
+#include <isc/region.h>
+
+#include <dns/types.h>
+#include <dns/name.h>
+
+/*
+ * This is the structure that is used for each node in the red/black
+ * tree of trees.  NOTE WELL:  the implementation manages this as a variable
+ * length structure, with the actual wire-format name being stored as
+ * a sequence of "name_length" bytes appended to this structure.  Allocating
+ * a contiguous block of memory for multiple dns_rbt_node structures is
+ * pretty much guaranteed to be useless.
+ *
+ * Note that the name_length variable will indicate how long just the length
+ * of the label(s) associated with this tree, not the length of the entire
+ * name the node is part of.
+ */
+
+typedef struct dns_rbt dns_rbt_t;
+
+typedef struct dns_rbt_node {
+	struct dns_rbt_node *parent;
+	struct dns_rbt_node *left;
+	struct dns_rbt_node *right;
+	struct dns_rbt_node *down;
+	enum { red, black } color;
+	void *data;
+	int name_length;
+} dns_rbt_node_t;
+
+isc_result_t dns_rbt_create(isc_mem_t *mctx, dns_rbt_t **rbtp);
+void dns_rbt_destroy(dns_rbt_t **rbtp);
+
+
+/*
+ * Add 'name' to the tree of trees, associated with 'data'.
+ *
+ * Notes:
+ *	'data' is never required to be non-NULL, but specifying it
+ *	when the name is added is faster than searching for 'name'
+ *	again and then setting the data pointer.
+ *
+ * Requires:
+ *	dns_name_isabsolute(name) == TRUE
+ *
+ * Ensures:
+ *
+ *	'name' is not altered in any way.
+ *
+ *	If result is success:
+ *		'name' is findable in the red/black tree of trees in O(log N).
+ *
+ * Returns:
+ *	Success
+ *	Resource Limit: Out of Memory
+ */
+isc_result_t dns_rbt_add_name(dns_rbt_t *rbt, dns_name_t *name, void *data);
+
+/*
+ * Delete 'name' from the tree of trees.
+ *
+ * Notes:
+ *	When 'name' is removed, all of its subnames are removed too.
+ *
+ * Requires:
+ *	dns_name_isabsolute(name) == TRUE
+ *
+ * Ensures:
+ *
+ *	'name' is not altered in any way.
+ *
+ *	'name' does not appear in the tree.
+ *
+ * Returns:
+ *	Success
+ *	Bad Form: Not Found
+ */
+isc_result_t dns_rbt_delete_name(dns_rbt_t *rbt, dns_name_t *name);
+
+/*
+ * Convert the sequence of labels stored at 'node' into a 'name'.
+ *
+ * Notes:
+ *	The name data pointed to by 'name' is the information stored
+ *	in the node, not a copy.  Altering the data at this pointer
+ *	will likely cause grief.
+ *
+ */
+void dns_rbt_namefromnode(dns_rbt_node_t *node, dns_name_t *name);
+
+/*
+ * Find the node for 'name'.
+ *
+ * Notes:
+ *	If 'up' is non-null, it will receive the value of the node
+ *	that has the down pointer to the found node.  If 'name' is
+ *	not found, then it '*up' is guaranteed to be NULL.  If
+ *	'name' is found in the top level tree of trees, '*up' will
+ *	also be NULL.
+ *
+ *	It is _not_ required that the node associated with 'name'
+ *	has a non-NULL data pointer.
+ */
+dns_rbt_node_t *dns_rbt_find_node(dns_rbt_t *rbt,
+				  dns_name_t *name, dns_rbt_node_t **up);
+
+/*
+ * Return the data pointer associated with 'name'.
+ *
+ * Notes:
+ *	Returns NULL if either the name could not be found, or
+ *	if the name is found but has a NULL data pointer.
+ */
+void *dns_rbt_find_name(dns_rbt_t *rbt, dns_name_t *name);

lib/dns/include/dns/redblack.h

@@ -0,0 +1,115 @@
+#include <isc/result.h>
+#include <isc/region.h>
+
+#include <dns/types.h>
+#include <dns/name.h>
+
+/*
+ * This is the structure that is used for each node in the red/black
+ * tree of trees.  NOTE WELL:  the implementation manages this as a variable
+ * length structure, with the actual wire-format name being stored as
+ * a sequence of "name_length" bytes appended to this structure.  Allocating
+ * a contiguous block of memory for multiple dns_rbt_node structures is
+ * pretty much guaranteed to be useless.
+ *
+ * Note that the name_length variable will indicate how long just the length
+ * of the label(s) associated with this tree, not the length of the entire
+ * name the node is part of.
+ */
+
+typedef struct dns_rbt dns_rbt_t;
+
+typedef struct dns_rbt_node {
+	struct dns_rbt_node *parent;
+	struct dns_rbt_node *left;
+	struct dns_rbt_node *right;
+	struct dns_rbt_node *down;
+	enum { red, black } color;
+	void *data;
+	int name_length;
+} dns_rbt_node_t;
+
+isc_result_t dns_rbt_create(isc_mem_t *mctx, dns_rbt_t **rbtp);
+void dns_rbt_destroy(dns_rbt_t **rbtp);
+
+
+/*
+ * Add 'name' to the tree of trees, associated with 'data'.
+ *
+ * Notes:
+ *	'data' is never required to be non-NULL, but specifying it
+ *	when the name is added is faster than searching for 'name'
+ *	again and then setting the data pointer.
+ *
+ * Requires:
+ *	dns_name_isabsolute(name) == TRUE
+ *
+ * Ensures:
+ *
+ *	'name' is not altered in any way.
+ *
+ *	If result is success:
+ *		'name' is findable in the red/black tree of trees in O(log N).
+ *
+ * Returns:
+ *	Success
+ *	Resource Limit: Out of Memory
+ */
+isc_result_t dns_rbt_add_name(dns_rbt_t *rbt, dns_name_t *name, void *data);
+
+/*
+ * Delete 'name' from the tree of trees.
+ *
+ * Notes:
+ *	When 'name' is removed, all of its subnames are removed too.
+ *
+ * Requires:
+ *	dns_name_isabsolute(name) == TRUE
+ *
+ * Ensures:
+ *
+ *	'name' is not altered in any way.
+ *
+ *	'name' does not appear in the tree.
+ *
+ * Returns:
+ *	Success
+ *	Bad Form: Not Found
+ */
+isc_result_t dns_rbt_delete_name(dns_rbt_t *rbt, dns_name_t *name);
+
+/*
+ * Convert the sequence of labels stored at 'node' into a 'name'.
+ *
+ * Notes:
+ *	The name data pointed to by 'name' is the information stored
+ *	in the node, not a copy.  Altering the data at this pointer
+ *	will likely cause grief.
+ *
+ */
+void dns_rbt_namefromnode(dns_rbt_node_t *node, dns_name_t *name);
+
+/*
+ * Find the node for 'name'.
+ *
+ * Notes:
+ *	If 'up' is non-null, it will receive the value of the node
+ *	that has the down pointer to the found node.  If 'name' is
+ *	not found, then it '*up' is guaranteed to be NULL.  If
+ *	'name' is found in the top level tree of trees, '*up' will
+ *	also be NULL.
+ *
+ *	It is _not_ required that the node associated with 'name'
+ *	has a non-NULL data pointer.
+ */
+dns_rbt_node_t *dns_rbt_find_node(dns_rbt_t *rbt,
+				  dns_name_t *name, dns_rbt_node_t **up);
+
+/*
+ * Return the data pointer associated with 'name'.
+ *
+ * Notes:
+ *	Returns NULL if either the name could not be found, or
+ *	if the name is found but has a NULL data pointer.
+ */
+void *dns_rbt_find_name(dns_rbt_t *rbt, dns_name_t *name);