From 8a9423ee95f61b613cfe961e1a5cbbf54d558bfc Mon Sep 17 00:00:00 2001
From: Rene Gollent <anevilyak@gmail.com>
Date: Sat, 27 Apr 2013 13:57:00 -0400
Subject: [PATCH] Add RangeList utility class.

- Tracks a set of ranges. Implicitly deals with collapsing overlapping
  ranges as they're added.
---
 src/apps/debugger/Jamfile            |   1 +
 src/apps/debugger/util/RangeList.cpp | 142 +++++++++++++++++++++++++++
 src/apps/debugger/util/RangeList.h   |  55 +++++++++++
 3 files changed, 198 insertions(+)
 create mode 100644 src/apps/debugger/util/RangeList.cpp
 create mode 100644 src/apps/debugger/util/RangeList.h

diff --git a/src/apps/debugger/Jamfile b/src/apps/debugger/Jamfile
index 6f90e1b418..caa8f1caef 100644
--- a/src/apps/debugger/Jamfile
+++ b/src/apps/debugger/Jamfile
@@ -266,6 +266,7 @@ Application Debugger :
 	ArchivingUtils.cpp
 	BitBuffer.cpp
 	IntegerFormatter.cpp
+	RangeList.cpp
 	StringUtils.cpp
 	Worker.cpp
 
diff --git a/src/apps/debugger/util/RangeList.cpp b/src/apps/debugger/util/RangeList.cpp
new file mode 100644
index 0000000000..8ab7f80bac
--- /dev/null
+++ b/src/apps/debugger/util/RangeList.cpp
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2013, Rene Gollent, rene@gollent.com.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include "RangeList.h"
+
+#include <AutoDeleter.h>
+
+
+RangeList::RangeList()
+	: BObjectList<Range>(20, true)
+{
+}
+
+
+RangeList::~RangeList()
+{
+}
+
+
+status_t
+RangeList::AddRange(int32 lowValue, int32 highValue)
+{
+	if (lowValue > highValue)
+		return B_BAD_VALUE;
+
+	int32 i = 0;
+	if (CountItems() != 0) {
+		for (; i < CountItems(); i++) {
+			Range* range = ItemAt(i);
+			if (lowValue < range->lowerBound) {
+				if (highValue < range->lowerBound) {
+					// the new range is completely below the bounds
+					// of the ranges we currently contain,
+					// insert it here.
+					break;
+				} else if (highValue <= range->upperBound) {
+					// the new range partly overlaps the lower
+					// current range
+					range->lowerBound = lowValue;
+					return B_OK;
+				} else {
+					// the new range completely encompasses
+					// the current range
+					range->lowerBound = lowValue;
+					range->upperBound = highValue;
+					_CollapseOverlappingRanges(i +1, highValue);
+				}
+
+			} else if (lowValue < range->upperBound) {
+				if (highValue <= range->upperBound) {
+					// the requested range is already completely contained
+					// within our existing range list
+					return B_OK;
+				} else {
+					range->upperBound = highValue;
+					_CollapseOverlappingRanges(i + 1, highValue);
+					return B_OK;
+				}
+			}
+		}
+	}
+
+	Range* range = new(std::nothrow) Range(lowValue, highValue);
+	if (range == NULL)
+		return B_NO_MEMORY;
+
+	BPrivate::ObjectDeleter<Range> rangeDeleter(range);
+	if (!AddItem(range, i))
+		return B_NO_MEMORY;
+
+	rangeDeleter.Detach();
+	return B_OK;
+}
+
+
+status_t
+RangeList::AddRange(const Range& range)
+{
+	return AddRange(range.lowerBound, range.upperBound);
+}
+
+
+void
+RangeList::RemoveRangeAt(int32 index)
+{
+	if (index < 0 || index >= CountItems())
+		return;
+
+	RemoveItem(ItemAt(index));
+}
+
+
+bool
+RangeList::Contains(int32 value) const
+{
+	for (int32 i = 0; i < CountItems(); i++) {
+		const Range* range = ItemAt(i);
+		if (value < range->lowerBound || value > range->upperBound)
+			break;
+		else if (value >= range->lowerBound && value <= range->upperBound)
+			return true;
+	}
+
+	return false;
+}
+
+
+int32
+RangeList::CountRanges() const
+{
+	return CountItems();
+}
+
+
+const Range*
+RangeList::RangeAt(int32 index) const
+{
+	return ItemAt(index);
+}
+
+
+void
+RangeList::_CollapseOverlappingRanges(int32 startIndex, int32 highValue)
+{
+	for (int32 i = startIndex; i < CountItems();) {
+		// check if it also overlaps any of the following
+		// ranges.
+		Range* nextRange = ItemAt(i);
+		if (nextRange->lowerBound > highValue)
+			return;
+		else if (nextRange->upperBound < highValue) {
+			RemoveItem(nextRange);
+			continue;
+		} else {
+			nextRange->lowerBound = highValue + 1;
+			return;
+		}
+	}
+}
diff --git a/src/apps/debugger/util/RangeList.h b/src/apps/debugger/util/RangeList.h
new file mode 100644
index 0000000000..b37fc1ba50
--- /dev/null
+++ b/src/apps/debugger/util/RangeList.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013, Rene Gollent, rene@gollent.com.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef RANGE_LIST_H
+#define RANGE_LIST_H
+
+
+#include <ObjectList.h>
+#include <SupportDefs.h>
+
+
+struct Range {
+	int32 lowerBound;
+	int32 upperBound;
+
+	Range()
+		:
+		lowerBound(-1),
+		upperBound(-1)
+	{
+	}
+
+	Range(int32 lowValue, int32 highValue)
+		:
+		lowerBound(lowValue),
+		upperBound(highValue)
+	{
+	}
+};
+
+
+class RangeList : private BObjectList<Range>
+{
+public:
+							RangeList();
+	virtual					~RangeList();
+
+
+			status_t		AddRange(int32 lowValue, int32 highValue);
+			status_t		AddRange(const Range& range);
+
+			void			RemoveRangeAt(int32 index);
+
+			int32			CountRanges() const;
+			const Range*	RangeAt(int32 index) const;
+
+			bool			Contains(int32 value) const;
+
+private:
+			void			_CollapseOverlappingRanges(int32 startIndex,
+								int32 highValue);
+};
+
+#endif // RANGE_LIST_H