/// <summary>
/// Defines a new segment in the file.
/// </summary>
/// <param name="offset">The offset at which the segment starts.</param>
/// <param name="size">The size of the segment.</param>
/// <param name="offsetAlignment">A power of two which the offset must be a multiple of (e.g. 0x1000 = 4kb-aligned).</param>
/// <param name="sizeAlignment">A power of two which the size must be a multiple of (e.g. 0x1000 = 4kb-aligned).</param>
/// <param name="resizeOrigin">The origin at which to insert/remove data in the segment.</param>
/// <returns>The segment's ID number which can be used to retrieve information about it.</returns>
public int DefineSegment(int offset, int size, int offsetAlignment, int sizeAlignment,
SegmentResizeOrigin resizeOrigin)
{
if (offset != Align(offset, offsetAlignment))
{
throw new ArgumentException("The segment offset is not aligned to the given alignment.");
}
if (size != Align(size, sizeAlignment))
{
throw new ArgumentException("The segment size is not aligned to the given alignment.");
}
if (_segmentsByOffset.ContainsKey(offset))
{
throw new ArgumentException("A segment has already been defined at the given offset.");
}
// Create and add the segment definition
int id = _segmentsById.Count;
var segment = new InternalSegment
{
ID = id,
Offset = offset,
Size = size,
OffsetAlignment = offsetAlignment,
SizeAlignment = sizeAlignment,
ResizeOrigin = resizeOrigin
};
_segmentsById.Add(segment);
_segmentsByOffset[offset] = segment;
RecalculateActualSizes();
return(id);
}
/// <summary>
/// Resizes a segment in the file.
/// </summary>
/// <param name="id">The ID of the segment to resize.</param>
/// <param name="newSize">The minimum amount of space that the segment must occupy.</param>
/// <param name="stream">The stream to write padding to.</param>
/// <returns>The new size of the segment after alignment has been applied.</returns>
public int ResizeSegment(int id, int newSize, IStream stream)
{
InternalSegment segment = GetSegmentFromID(id);
int oldSize = segment.Size;
if (newSize == oldSize)
{
return(oldSize);
}
// Change the size of the segment
int oldActualSize = segment.ActualSize;
int oldSegmentEnd = segment.Offset + segment.ActualSize;
segment.Size = Align(newSize, segment.SizeAlignment);
segment.ActualSize = Math.Max(segment.Size, segment.ActualSize);
// Recalculate the segment offsets,
// and then use the recalculated offsets to recalculate the sizes
RecalculateOffsets();
RecalculateActualSizes();
int resizeOffset;
switch (segment.ResizeOrigin)
{
case SegmentResizeOrigin.Beginning:
resizeOffset = segment.Offset;
break;
case SegmentResizeOrigin.End:
resizeOffset = oldSegmentEnd;
break;
default:
throw new ArgumentException("The segment cannot be resized.");
}
// Insert/remove data into/from the stream
// FIXME: There's a bug here where changing the size of a SegmentResizeOrigin.Beginning segment won't move the data back if ActualSize doesn't change
// Some sort of StreamUtil.Copy() method is necessary for that
stream.SeekTo(resizeOffset);
if (oldActualSize < segment.ActualSize)
{
StreamUtil.Insert(stream, segment.ActualSize - oldActualSize, 0);
}
else if (segment.ActualSize < oldActualSize)
{
throw new NotImplementedException("Segment shrinking is not supported yet.");
}
OnSegmentResized(new SegmentResizedEventArgs(id, oldSize, segment.Size, segment.ResizeOrigin));
return(segment.Size);
}
/// <summary>
/// Recalculates the offset of each segment in the file after a segment's size has been changed.
/// </summary>
private void RecalculateOffsets()
{
IList <InternalSegment> segments = _segmentsByOffset.Values;
for (int i = 1; i < segments.Count; i++)
{
InternalSegment thisSegment = segments[i];
InternalSegment prevSegment = segments[i - 1];
thisSegment.Offset = Align(prevSegment.Offset + prevSegment.ActualSize, thisSegment.OffsetAlignment);
}
}
/// <summary>
/// Defines a new segment in the file.
/// </summary>
/// <param name="offset">The offset at which the segment starts.</param>
/// <param name="size">The size of the segment.</param>
/// <param name="offsetAlignment">A power of two which the offset must be a multiple of (e.g. 0x1000 = 4kb-aligned).</param>
/// <param name="sizeAlignment">A power of two which the size must be a multiple of (e.g. 0x1000 = 4kb-aligned).</param>
/// <param name="resizeOrigin">The origin at which to insert/remove data in the segment.</param>
/// <returns>The segment's ID number which can be used to retrieve information about it.</returns>
public int DefineSegment(int offset, int size, int offsetAlignment, int sizeAlignment, SegmentResizeOrigin resizeOrigin)
{
if (offset != Align(offset, offsetAlignment))
throw new ArgumentException("The segment offset is not aligned to the given alignment.");
if (size != Align(size, sizeAlignment))
throw new ArgumentException("The segment size is not aligned to the given alignment.");
if (_segmentsByOffset.ContainsKey(offset))
throw new ArgumentException("A segment has already been defined at the given offset.");
// Create and add the segment definition
int id = _segmentsById.Count;
var segment = new InternalSegment
{
ID = id,
Offset = offset,
Size = size,
OffsetAlignment = offsetAlignment,
SizeAlignment = sizeAlignment,
ResizeOrigin = resizeOrigin
};
_segmentsById.Add(segment);
_segmentsByOffset[offset] = segment;
RecalculateActualSizes();
return id;
}
