/// <summary>
/// Resizes a block of tag data, updating relative pointers which do not point into the block.
/// </summary>
/// <param name="stream">The stream to write to.</param>
/// <param name="tag">The tag.</param>
/// <param name="startOffset">The offset, from the start of the tag's data, where the block to resize begins at.</param>
/// <param name="oldSize">The current size of the block to resize.</param>
/// <param name="newSize">The new size of the block.</param>
/// <param name="origin">The origin where data should be inserted or removed.</param>
public void ResizeTagData(Stream stream, TagInstance tag, long startOffset, long oldSize, long newSize, ResizeOrigin origin)
{
if (tag == null)
{
throw new ArgumentNullException("tag");
}
if (tag.HeaderOffset < 0)
{
throw new ArgumentException("The tag is not in the cache file");
}
if (oldSize < 0)
{
throw new ArgumentException("The old block size cannot be negative");
}
if (newSize < 0)
{
throw new ArgumentException("Cannot resize a block to a negative size");
}
if (newSize == tag.DataSize)
{
return;
}
// Correct offsets pointing after the block
var sizeDelta = newSize - oldSize;
var blockEndOffset = startOffset + oldSize;
tag.DataSize += sizeDelta;
foreach (var fixup in tag.DataFixups.Concat(tag.ResourceFixups))
{
if (fixup.WriteOffset >= blockEndOffset)
{
fixup.WriteOffset = (uint)(fixup.WriteOffset + sizeDelta);
}
if (fixup.TargetOffset >= blockEndOffset)
{
fixup.TargetOffset = (uint)(fixup.TargetOffset + sizeDelta);
}
}
if (tag.MainStructOffset >= blockEndOffset)
{
tag.MainStructOffset = (uint)(tag.MainStructOffset + sizeDelta);
}
FixTagOffsets(tag.DataOffset + blockEndOffset, sizeDelta, tag);
// Insert/remove the data
long editOffset;
if (origin == ResizeOrigin.Beginning)
{
editOffset = startOffset;
}
else if (sizeDelta > 0)
{
editOffset = blockEndOffset;
}
else
{
editOffset = blockEndOffset + sizeDelta;
}
stream.Position = tag.DataOffset + editOffset;
if (sizeDelta > 0)
{
StreamUtil.Insert(stream, (int)sizeDelta, 0);
}
else
{
StreamUtil.Remove(stream, (int)-sizeDelta);
}
UpdateTag(stream, tag);
}
/// <summary>
/// Inserts or removes data in a tag.
/// </summary>
/// <param name="stream">The stream to write to.</param>
/// <param name="tag">The tag.</param>
/// <param name="insertOffset">The offset, from the start of the tag's header, to insert data at.</param>
/// <param name="sizeDelta">The size of the data to insert or remove. If positive, data will be inserted. If negative, data will be removed.</param>
/// <param name="origin">The type of resize to perform. See <see cref="InsertOrigin"/>.</param>
/// <param name="mode">The resize mode. See <see cref="ResizeMode"/>.</param>
private void ResizeTag(Stream stream, HaloTag tag, uint insertOffset, int sizeDelta, InsertOrigin origin, ResizeMode mode)
{
if (sizeDelta == 0)
{
return;
}
var headerSize = GetHeaderSize(tag);
if (sizeDelta < 0 && ((origin == InsertOrigin.Before && -sizeDelta > insertOffset) || (origin == InsertOrigin.After && insertOffset + -sizeDelta > headerSize + tag.Size)))
{
throw new ArgumentException("Cannot remove more bytes than there are available in the tag");
}
// In insertion mode, correct relative offsets to account for inserted data
var relativeCompareOffset = (origin == InsertOrigin.Before) ? insertOffset : insertOffset + 1; // hack
if (headerSize < relativeCompareOffset)
{
tag.Size = (uint)(tag.Size + sizeDelta);
if (mode == ResizeMode.Insert)
{
foreach (var fixup in tag.DataFixups.Concat(tag.ResourceFixups))
{
if (fixup.WriteOffset + headerSize >= relativeCompareOffset)
{
fixup.WriteOffset = (uint)(fixup.WriteOffset + sizeDelta);
}
if (fixup.TargetOffset + headerSize >= relativeCompareOffset)
{
fixup.TargetOffset = (uint)(fixup.TargetOffset + sizeDelta);
}
}
if (tag.MainStructOffset + headerSize >= relativeCompareOffset)
{
tag.MainStructOffset = (uint)(tag.MainStructOffset + sizeDelta);
}
}
}
// Correct tag offsets
var absoluteOffset = _headerOffsets[tag.Index] + insertOffset;
var absoluteCompareOffset = (origin == InsertOrigin.Before) ? absoluteOffset : absoluteOffset + 1; // hack
for (var i = 0; i < _tags.Count; i++)
{
if (_tags[i] == null)
{
continue;
}
if (_headerOffsets[i] >= absoluteCompareOffset) // Header offset (absolute)
{
_headerOffsets[i] = (uint)(_headerOffsets[i] + sizeDelta);
}
if (_tags[i].Offset >= absoluteCompareOffset) // Data offset (absolute)
{
_tags[i].Offset = (uint)(_tags[i].Offset + sizeDelta);
}
}
// Insert/remove the data
if (sizeDelta < 0 && origin == InsertOrigin.Before)
{
absoluteOffset = (uint)(absoluteOffset + sizeDelta);
}
stream.Position = absoluteOffset;
if (sizeDelta > 0)
{
StreamUtil.Insert(stream, sizeDelta, 0);
}
else
{
StreamUtil.Remove(stream, -sizeDelta);
}
}