Add ut0bh.h and ut0bh.c.

1 files changed, 164 insertions, 0 deletions

diff --git a/storage/innobase/ut/ut0bh.c b/storage/innobase/ut/ut0bh.c
new file mode 100644
index 00000000000..ae0b1aff207
--- /dev/null
+++ b/storage/innobase/ut/ut0bh.c
@@ -0,0 +1,164 @@
+/***************************************************************************//**
+Copyright (c) 2010, 2011, Oracle Corpn. All Rights Reserved.
+
+Portions of this file contain modifications contributed and copyrighted by
+Sun Microsystems, Inc. Those modifications are gratefully acknowledged and
+are described briefly in the InnoDB documentation. The contributions by
+Sun Microsystems are incorporated with their permission, and subject to the
+conditions contained in the file COPYING.Sun_Microsystems.
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+
+*****************************************************************************/
+
+/******************************************************************//**
+@file ut/ut0bh.c
+Binary min-heap implementation.
+
+Created 2010-05-28 by Sunny Bains
+*******************************************************/
+
+#include "ut0bh.h"
+#include "ut0mem.h"
+
+#ifdef UNIV_NONINL
+#include "ut0bh.ic"
+#endif
+
+#include <string.h>
+
+/**********************************************************************//**
+Create a binary heap.
+@return a new binary heap */
+UNIV_INTERN
+ib_bh_t*
+ib_bh_create(
+/*=========*/
+	ib_bh_cmp_t	compare,		/*!< in: comparator */
+	ulint		sizeof_elem,		/*!< in: size of one element */
+	ulint		max_elems)		/*!< in: max elements allowed */
+{
+	ulint		sz;
+	ib_bh_t*	ib_bh;
+
+	sz = sizeof(*ib_bh) + (sizeof_elem * max_elems);
+
+	ib_bh = (ib_bh_t*) ut_malloc(sz);
+	memset(ib_bh, 0x0, sz);
+
+	ib_bh->compare = compare;
+	ib_bh->max_elems = max_elems;
+	ib_bh->sizeof_elem = sizeof_elem;
+
+	return(ib_bh);
+}
+
+/**********************************************************************//**
+Free a binary heap.
+@return a new binary heap */
+UNIV_INTERN
+void
+ib_bh_free(
+/*=======*/
+	ib_bh_t*	ib_bh)			/*!< in/own: instance */
+{
+	ut_free(ib_bh);
+}
+
+/**********************************************************************//**
+Add an element to the binary heap. Note: The element is copied.
+@return pointer to added element or NULL if full. */
+UNIV_INTERN
+void*
+ib_bh_push(
+/*=======*/
+	ib_bh_t*	ib_bh,			/*!< in/out: instance */
+	const void*	elem)			/*!< in: element to add */
+{
+	void*		ptr;
+
+	if (ib_bh_is_full(ib_bh)) {
+		return(NULL);
+	} else if (ib_bh_is_empty(ib_bh)) {
+		++ib_bh->n_elems;
+		return(ib_bh_set(ib_bh, 0, elem));
+	} else {
+		ulint	i;
+
+		i = ib_bh->n_elems;
+
+		++ib_bh->n_elems;
+
+		for (ptr = ib_bh_get(ib_bh, i >> 1);
+		     i > 0 && ib_bh->compare(ptr, elem) > 0;
+		     i >>= 1, ptr = ib_bh_get(ib_bh, i >> 1)) {
+
+			ib_bh_set(ib_bh, i, ptr);
+		}
+
+		ptr = ib_bh_set(ib_bh, i, elem);
+	}
+
+	return(ptr);
+}
+
+/**********************************************************************//**
+Remove the first element from the binary heap. */
+UNIV_INTERN
+void
+ib_bh_pop(
+/*======*/
+	ib_bh_t*	ib_bh)			/*!< in/out: instance */
+{
+	byte*		ptr;
+	byte*		last;
+	ulint		parent = 0;
+
+	if (ib_bh_is_empty(ib_bh)) {
+		return;
+	} else if (ib_bh_size(ib_bh) == 1) {
+		--ib_bh->n_elems;
+		return;
+	}
+
+	last = (byte*) ib_bh_last(ib_bh);
+
+	/* Start from the child node */
+	ptr = (byte*) ib_bh_get(ib_bh, 1);
+
+	while (ptr < last) {
+		/* If the "right" child node is < "left" child node */
+		if (ib_bh->compare(ptr + ib_bh->sizeof_elem, ptr) < 0) {
+			ptr += ib_bh->sizeof_elem;
+		}
+
+		if (ib_bh->compare(last, ptr) <= 0) {
+			break;
+		}
+
+		ib_bh_set(ib_bh, parent, ptr);
+
+		parent = (ptr - (byte*) ib_bh_first(ib_bh))
+		       / ib_bh->sizeof_elem;
+
+		if ((parent << 1) >= ib_bh_size(ib_bh)) {
+			break;
+		}
+
+		ptr = (byte*) ib_bh_get(ib_bh, parent << 1);
+	}
+
+	--ib_bh->n_elems;
+
+	ib_bh_set(ib_bh, parent, last);
+}