Reduce memory usage and increase performance with a better data structure.

git-svn-id: http://svn.drobilla.net/sord/trunk@307 3d64ff67-21c5-427c-a301-fe4f08042e5a

1 files changed, 144 insertions, 0 deletions

diff --git a/src/zix/btree.h b/src/zix/btree.h
new file mode 100644
index 0000000..0cd549a
--- /dev/null
+++ b/src/zix/btree.h
@@ -0,0 +1,144 @@
+/*
+  Copyright 2011-2014 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#ifndef ZIX_BTREE_H
+#define ZIX_BTREE_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "zix/common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+   @addtogroup zix
+   @{
+   @name BTree
+   @{
+*/
+
+/**
+   A B-Tree.
+*/
+typedef struct ZixBTreeImpl ZixBTree;
+
+/**
+   A B-Tree node (opaque).
+*/
+typedef struct ZixBTreeNodeImpl ZixBTreeNode;
+
+/**
+   An iterator over a B-Tree.
+
+   Note that modifying the trees invalidates all iterators, so all iterators
+   are const iterators.
+*/
+typedef struct ZixBTreeIterImpl ZixBTreeIter;
+
+/**
+   Create a new (empty) B-Tree.
+*/
+ZIX_API ZixBTree*
+zix_btree_new(ZixComparator  cmp,
+              void*          cmp_data,
+              ZixDestroyFunc destroy);
+
+/**
+   Free `t`.
+*/
+ZIX_API void
+zix_btree_free(ZixBTree* t);
+
+/**
+   Return the number of elements in `t`.
+*/
+ZIX_API size_t
+zix_btree_size(const ZixBTree* t);
+
+/**
+   Insert the element `e` into `t`.
+*/
+ZIX_API ZixStatus
+zix_btree_insert(ZixBTree* t, void* e);
+
+/**
+   Remove the value `e` from `t`, set `removed` to the removed pointer.
+*/
+ZIX_API ZixStatus
+zix_btree_remove(ZixBTree* t, const void* e, void** removed);
+
+/**
+   Set `ti` to an element equal to `e` in `t`.
+   If no such item exists, `ti` is set to NULL.
+*/
+ZIX_API ZixStatus
+zix_btree_find(const ZixBTree* t, const void* e, ZixBTreeIter** ti);
+
+/**
+   Set `ti` to the smallest element in `t` that is not less than `e`.
+
+   Wildcards are supported, so if the search key `e` compares equal to many
+   values in the tree, `ti` will be set to the least such element.  The search
+   key `e` is always passed as the second argument to the comparator.
+*/
+ZIX_API ZixStatus
+zix_btree_lower_bound(const ZixBTree* t, const void* e, ZixBTreeIter** ti);
+
+/**
+   Return the data associated with the given tree item.
+*/
+ZIX_API void*
+zix_btree_get(const ZixBTreeIter* ti);
+
+/**
+   Return an iterator to the first (smallest) element in `t`.
+
+   The returned iterator must be freed with zix_btree_iter_free().
+*/
+ZIX_API ZixBTreeIter*
+zix_btree_begin(const ZixBTree* t);
+
+/**
+   Return true iff `i` is an iterator to the end of its tree.
+*/
+ZIX_API bool
+zix_btree_iter_is_end(const ZixBTreeIter* i);
+
+/**
+   Increment `i` to point to the next element in the tree.
+*/
+ZIX_API void
+zix_btree_iter_increment(ZixBTreeIter* i);
+
+/**
+   Free `i`.
+*/
+ZIX_API void
+zix_btree_iter_free(ZixBTreeIter* i);
+
+/**
+   @}
+   @}
+*/
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* ZIX_BTREE_H */