The info about partitionable space will be provided by the userland disk

system add-ons. First work to make this class usable for them.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22539 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/storage/PartitioningInfo.h

@@ -12,25 +12,35 @@ struct partitionable_space_data;
 
 class BPartitioningInfo {
 public:
-	BPartitioningInfo();
-	virtual ~BPartitioningInfo();
+								BPartitioningInfo();
+	virtual						~BPartitioningInfo();
 
-	void Unset();
+			status_t			SetTo(off_t offset, off_t size);
+			void				Unset();
 
-	partition_id PartitionID() const;
+			status_t			ExcludeOccupiedSpace(off_t offset,
+									off_t size);
 
-	status_t GetPartitionableSpaceAt(int32 index, off_t *offset,
-									 off_t *size) const;
-	int32 CountPartitionableSpaces() const;
+// TODO: We don't need the partition ID.
+			partition_id		PartitionID() const;
+
+			status_t			GetPartitionableSpaceAt(int32 index,
+									off_t* offset, off_t*size) const;
+			int32				CountPartitionableSpaces() const;
 
 private:
-	status_t _SetTo(partition_id partition, int32 changeCounter);
+			status_t			_SetTo(partition_id partition,
+									int32 changeCounter);
+
+			status_t			_InsertSpaces(int32 index, int32 count);
+			void				_RemoveSpaces(int32 index, int32 count);
 
 	friend class BPartition;
 
-	partition_id				fPartitionID;
-	partitionable_space_data	*fSpaces;
-	int32						fCount;
+			partition_id		fPartitionID;
+			partitionable_space_data* fSpaces;
+			int32				fCount;
+			int32				fCapacity;
 };
 
 #endif	// _PARTITIONING_INFO_H

src/kits/storage/PartitioningInfo.cpp

@@ -3,6 +3,8 @@
 //  by the OpenBeOS license.
 //---------------------------------------------------------------------
 
+#include <string.h>
+
 #include <new>
 
 #include <PartitioningInfo.h>
@@ -10,22 +12,53 @@
 #include <syscalls.h>
 #include <disk_device_manager/ddm_userland_interface.h>
 
+
 using namespace std;
 
+
 // constructor
 BPartitioningInfo::BPartitioningInfo()
 	: fPartitionID(-1),
 	  fSpaces(NULL),
-	  fCount(0)
+	  fCount(0),
+	  fCapacity(0)
 {
 }
 
+
 // destructor
 BPartitioningInfo::~BPartitioningInfo()
 {
 	Unset();
 }
 
+
+// SetTo
+status_t
+BPartitioningInfo::SetTo(off_t offset, off_t size)
+{
+	fPartitionID = -1;
+	delete[] fSpaces;
+
+	if (size > 0) {
+		fSpaces = new(nothrow) partitionable_space_data[1];
+		if (!fSpaces)
+			return B_NO_MEMORY;
+
+		fCount = 1;
+		fSpaces[0].offset = offset;
+		fSpaces[0].size = size;
+	} else {
+		fSpaces = NULL;
+		fCount = 0;
+	}
+
+	fCapacity = fCount;
+
+	return B_OK;
+}
+
+
 // Unset
 void
 BPartitioningInfo::Unset()
@@ -34,8 +67,80 @@ BPartitioningInfo::Unset()
 	fPartitionID = -1;
 	fSpaces = NULL;
 	fCount = 0;
+	fCapacity = 0;
 }
 
+
+// ExcludeOccupiedSpace
+status_t
+BPartitioningInfo::ExcludeOccupiedSpace(off_t offset, off_t size)
+{
+	if (size <= 0)
+		return B_OK;
+
+	int32 leftIndex = -1;
+	int32 rightIndex = -1;
+	for (int32 i = 0; i < fCount; i++) {
+		if (leftIndex == -1
+			&& offset < fSpaces[i].offset + fSpaces[i].size) {
+			leftIndex = i;
+		}
+
+		if (fSpaces[i].offset < offset + size)
+			rightIndex = i;
+	}
+
+	// If there's no intersection with any free space, we're done.
+	if (leftIndex == -1 || rightIndex == -1 || leftIndex > rightIndex)
+		return B_OK;
+
+	partitionable_space_data& leftSpace = fSpaces[leftIndex];
+	partitionable_space_data& rightSpace = fSpaces[rightIndex];
+
+	off_t rightSpaceEnd = rightSpace.offset + rightSpace.size;
+
+	// special case: split a single space in two
+	if (leftIndex == rightIndex && leftSpace.offset < offset
+		&& rightSpaceEnd > offset + size) {
+		// add a space after this one
+		status_t error = _InsertSpaces(leftIndex + 1, 1);
+		if (error != B_OK)
+			return error;
+
+		partitionable_space_data& space = fSpaces[leftIndex];
+		partitionable_space_data& newSpace = fSpaces[leftIndex + 1];
+
+		space.size = offset - space.offset;
+
+		newSpace.offset = offset + size;
+		newSpace.size = rightSpaceEnd - newSpace.offset;
+
+		return B_OK;
+	}
+
+	// check whether the first affected space is eaten completely
+	int32 deleteFirst = leftIndex;
+	if (leftSpace.offset < offset) {
+		leftSpace.size = offset - leftSpace.offset;
+		deleteFirst++;
+	}
+
+	// check whether the last affected space is eaten completely
+	int32 deleteLast = rightIndex;
+	if (rightSpaceEnd > offset + size) {
+		rightSpace.offset = offset + size;
+		rightSpace.size = rightSpaceEnd - rightSpace.offset;
+		deleteLast--;
+	}
+
+	// remove all spaces that are completely eaten
+	if (deleteFirst <= deleteLast)
+		_RemoveSpaces(deleteFirst, deleteLast - deleteFirst + 1);
+
+	return B_OK;
+}
+
+
 // PartitionID
 partition_id
 BPartitioningInfo::PartitionID() const
@@ -43,6 +148,7 @@ BPartitioningInfo::PartitionID() const
 	return fPartitionID;
 }
 
+
 // GetPartitionableSpaceAt
 status_t
 BPartitioningInfo::GetPartitionableSpaceAt(int32 index, off_t *offset,
@@ -55,6 +161,7 @@ BPartitioningInfo::GetPartitionableSpaceAt(int32 index, off_t *offset,
 	return B_OK;
 }
 
+
 // CountPartitionableSpaces
 int32
 BPartitioningInfo::CountPartitionableSpaces() const
@@ -62,6 +169,7 @@ BPartitioningInfo::CountPartitionableSpaces() const
 	return fCount;
 }
 
+
 // _SetTo
 status_t
 BPartitioningInfo::_SetTo(partition_id partition, int32 changeCounter)
@@ -100,3 +208,55 @@ BPartitioningInfo::_SetTo(partition_id partition, int32 changeCounter)
 	return error;
 }
 
+
+// _InsertSpaces
+status_t
+BPartitioningInfo::_InsertSpaces(int32 index, int32 count)
+{
+	if (index <= 0 || index > fCount || count <= 0)
+		return B_BAD_VALUE;
+
+	// If the capacity is sufficient, we just need to copy the spaces to create
+	// a gap.
+	if (fCount + count <= fCapacity) {
+		memmove(fSpaces + index + count, fSpaces + index, fCount - index);
+		fCount += count;
+		return B_OK;
+	}
+
+	// alloc new array
+	int32 capacity = (fCount + count) * 2;
+		// add a bit room for further resizing
+
+	partitionable_space_data* spaces
+		= new(nothrow) partitionable_space_data[capacity];
+	if (!spaces)
+		return B_NO_MEMORY;
+
+	// copy items
+	memcpy(spaces, fSpaces, index);
+	memcpy(spaces + index + count, fSpaces + index, fCount - index);
+
+	delete[] fSpaces;
+	fSpaces = spaces;
+	fCapacity = capacity;
+	fCount += count;
+
+	return B_OK;
+}
+
+
+// _RemoveSpaces
+void
+BPartitioningInfo::_RemoveSpaces(int32 index, int32 count)
+{
+	if (index <= 0 || count <= 0 || index + count > fCount)
+		return;
+
+	if (count < fCount) {
+		int32 endIndex = index + count;
+		memmove(fSpaces + index, fSpaces + endIndex, fCount - endIndex);
+	}
+
+	fCount -= count;
+}