1 files changed, 88 insertions, 0 deletions
diff --git a/layout/generic/nsIntervalSet.cpp b/layout/generic/nsIntervalSet.cpp
new file mode 100644
index 000000000..cc72a811e
--- /dev/null
+++ b/layout/generic/nsIntervalSet.cpp
@@ -0,0 +1,88 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+// vim:cindent:ts=8:et:sw=4:
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* a set of ranges on a number-line */
+
+#include "nsIntervalSet.h"
+#include <new>
+#include <algorithm>
+
+nsIntervalSet::nsIntervalSet(IntervalSetAlloc aAlloc, IntervalSetFree aFree,
+                             void* aAllocatorClosure)
+    : mList(nullptr),
+      mAlloc(aAlloc),
+      mFree(aFree),
+      mAllocatorClosure(aAllocatorClosure)
+{
+    NS_ASSERTION(mAlloc && mFree, "null callback params");
+}
+
+nsIntervalSet::~nsIntervalSet()
+{
+    Interval *current = mList;
+    while (current) {
+        Interval *trash = current;
+        current = current->mNext;
+        FreeInterval(trash);
+    }
+}
+
+void nsIntervalSet::FreeInterval(nsIntervalSet::Interval *aInterval)
+{
+    NS_ASSERTION(aInterval, "null interval");
+
+    aInterval->Interval::~Interval();
+    (*mFree)(sizeof(Interval), aInterval, mAllocatorClosure);
+}
+
+void nsIntervalSet::IncludeInterval(coord_type aBegin, coord_type aEnd)
+{
+    Interval *newInterval = static_cast<Interval*>
+                                       ((*mAlloc)(sizeof(Interval), mAllocatorClosure));
+    if (!newInterval) {
+        NS_NOTREACHED("allocation failure");
+        return;
+    }
+    new(newInterval) Interval(aBegin, aEnd);
+
+    Interval **current = &mList;
+    while (*current && (*current)->mEnd < aBegin)
+        current = &(*current)->mNext;
+
+    newInterval->mNext = *current;
+    *current = newInterval;
+
+    Interval *subsumed = newInterval->mNext;
+    while (subsumed && subsumed->mBegin <= aEnd) {
+        newInterval->mBegin = std::min(newInterval->mBegin, subsumed->mBegin);
+        newInterval->mEnd = std::max(newInterval->mEnd, subsumed->mEnd);
+        newInterval->mNext = subsumed->mNext;
+        FreeInterval(subsumed);
+        subsumed = newInterval->mNext;
+    }
+}
+
+bool nsIntervalSet::Intersects(coord_type aBegin, coord_type aEnd) const
+{
+    Interval *current = mList;
+    while (current && current->mBegin <= aEnd) {
+        if (current->mEnd >= aBegin)
+            return true;
+        current = current->mNext;
+    }
+    return false;
+}
+
+bool nsIntervalSet::Contains(coord_type aBegin, coord_type aEnd) const
+{
+    Interval *current = mList;
+    while (current && current->mBegin <= aBegin) {
+        if (current->mEnd >= aEnd)
+            return true;
+        current = current->mNext;
+    }
+    return false;
+}