/// <summary>
/// Estimates the file size of the resulting archive.
/// </summary>
public int EstimateFileSize(ArchiveWriterOptions options)
{
int result = 0;
result += sizeof(int); // Number of items.
result += Groups.Count; // Number of items for each id.
result = Utilities.RoundUp(result, 4); // Alignment
result += Groups.Keys.Count * sizeof(int); // First item index for each group & ID for each group.
// Calculate number of total items.
int totalItems = 0;
foreach (var group in Groups)
{
totalItems += group.Value.Files.Count;
}
// Align starting offset.
result = Utilities.RoundUp((int)result + (sizeof(int) * totalItems), options.Alignment);
foreach (var group in Groups)
{
foreach (var file in group.Value.Files)
{
result += file.Data.Length;
result = Utilities.RoundUp(result, options.Alignment);
}
}
return(result);
}
/// <summary>
/// Writes the contents of the archive to be generated to the stream.
/// </summary>
/// <param name="writeStream">The stream to write to.</param>
/// <param name="options">The options for packing this archive.</param>
public void Write(Stream writeStream, ArchiveWriterOptions options)
{
using var stream = new ExtendedMemoryStream(EstimateFileSize(options) + 1);
using EndianMemoryStream endianStream = options.BigEndian ? (EndianMemoryStream) new BigEndianMemoryStream(stream) : new LittleEndianMemoryStream(stream);
// Number of items.
endianStream.Write <int>(Groups.Keys.Count);
// Number of items for each id.
foreach (var group in Groups)
{
endianStream.Write <byte>((byte)group.Value.Files.Count);
}
endianStream.AddPadding(0x00, 4);
// Write first item index for each group.
ushort totalItems = 0;
foreach (var group in Groups)
{
endianStream.Write <ushort>(totalItems);
totalItems += (ushort)group.Value.Files.Count;
}
// Write ID for each group.
foreach (var group in Groups)
{
endianStream.Write <ushort>(group.Value.Id);
}
// Write offsets for each file and pad.
int firstWriteOffset = Utilities.RoundUp((int)endianStream.Stream.Position + (sizeof(int) * totalItems), options.Alignment);
if (firstWriteOffset < options.MinOffset)
{
firstWriteOffset = options.MinOffset;
}
int fileWriteOffset = firstWriteOffset;
foreach (var group in Groups)
{
foreach (var file in group.Value.Files)
{
endianStream.Write <int>(file.Data.Length <= 0 ? 0 : fileWriteOffset);
fileWriteOffset += file.Data.Length;
fileWriteOffset = Utilities.RoundUp(fileWriteOffset, options.Alignment);
}
}
// Write files.
endianStream.Write(new byte[(int)(firstWriteOffset - endianStream.Stream.Position)]); // Alignment
foreach (var file in Groups.SelectMany(x => x.Value.Files))
{
endianStream.Write(file.Data);
endianStream.AddPadding(options.Alignment);
}
writeStream.Write(endianStream.ToArray());
}
