1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/memRegion.cpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,100 @@
1.4 +/*
1.5 + * Copyright 2000-2004 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// A very simple data structure representing a contigous word-aligned
1.29 +// region of address space.
1.30 +
1.31 +#include "incls/_precompiled.incl"
1.32 +#include "incls/_memRegion.cpp.incl"
1.33 +
1.34 +MemRegion MemRegion::intersection(const MemRegion mr2) const {
1.35 + MemRegion res;
1.36 + HeapWord* res_start = MAX2(start(), mr2.start());
1.37 + HeapWord* res_end = MIN2(end(), mr2.end());
1.38 + if (res_start < res_end) {
1.39 + res.set_start(res_start);
1.40 + res.set_end(res_end);
1.41 + }
1.42 + return res;
1.43 +}
1.44 +
1.45 +MemRegion MemRegion::_union(const MemRegion mr2) const {
1.46 + // If one region is empty, return the other
1.47 + if (is_empty()) return mr2;
1.48 + if (mr2.is_empty()) return MemRegion(start(), end());
1.49 +
1.50 + // Otherwise, regions must overlap or be adjacent
1.51 + assert(((start() <= mr2.start()) && (end() >= mr2.start())) ||
1.52 + ((mr2.start() <= start()) && (mr2.end() >= start())),
1.53 + "non-adjacent or overlapping regions");
1.54 + MemRegion res;
1.55 + HeapWord* res_start = MIN2(start(), mr2.start());
1.56 + HeapWord* res_end = MAX2(end(), mr2.end());
1.57 + res.set_start(res_start);
1.58 + res.set_end(res_end);
1.59 + return res;
1.60 +}
1.61 +
1.62 +MemRegion MemRegion::minus(const MemRegion mr2) const {
1.63 + // There seem to be 6 cases:
1.64 + // |this MemRegion|
1.65 + // |strictly below|
1.66 + // |overlap beginning|
1.67 + // |interior|
1.68 + // |overlap ending|
1.69 + // |strictly above|
1.70 + // |completely overlapping|
1.71 + // We can't deal with an interior case because it would
1.72 + // produce two disjoint regions as a result.
1.73 + // We aren't trying to be optimal in the number of tests below,
1.74 + // but the order is important to distinguish the strictly cases
1.75 + // from the overlapping cases.
1.76 + if (mr2.end() <= start()) {
1.77 + // strictly below
1.78 + return MemRegion(start(), end());
1.79 + }
1.80 + if (mr2.start() <= start() && mr2.end() <= end()) {
1.81 + // overlap beginning
1.82 + return MemRegion(mr2.end(), end());
1.83 + }
1.84 + if (mr2.start() >= end()) {
1.85 + // strictly above
1.86 + return MemRegion(start(), end());
1.87 + }
1.88 + if (mr2.start() >= start() && mr2.end() >= end()) {
1.89 + // overlap ending
1.90 + return MemRegion(start(), mr2.start());
1.91 + }
1.92 + if (mr2.start() <= start() && mr2.end() >= end()) {
1.93 + // completely overlapping
1.94 + return MemRegion();
1.95 + }
1.96 + if (mr2.start() > start() && mr2.end() < end()) {
1.97 + // interior
1.98 + guarantee(false, "MemRegion::minus, but interior");
1.99 + return MemRegion();
1.100 + }
1.101 + ShouldNotReachHere();
1.102 + return MemRegion();
1.103 +}
