/// <summary>
/// Using to decompress (parse bytes to Metadata type)
/// </summary>
internal Metadata(byte[] bytes, int metadataSize)
{
try
{
_magicWordBytes = Encoding.UTF8.GetBytes(_magicWord);
var byteList = bytes.ToList();
int offset = 0;
if (Encoding.UTF8.GetString(byteList.GetRange(offset, _magicWordBytes.Length).ToArray()) != _magicWord)
{
throw new WrongSourceFileException("File header has been corrupted or file has not been compressed by this compressor.");
}
offset += _magicWordBytes.Length;
MetadataSize = metadataSize;
offset += sizeof(int);
FileExtension = Encoding.UTF8.GetString(byteList.GetRange(offset, 8).ToArray()).Replace("\0", "");
offset += 8;
while (offset < byteList.Count)
{
var compressedOffset = BitConverter.ToInt64(byteList.GetRange(offset, sizeof(long)).ToArray(), 0);
offset += sizeof(long);
var decompressedOffset = BitConverter.ToInt64(byteList.GetRange(offset, sizeof(long)).ToArray(), 0);
offset += sizeof(long);
var chunk = new ChunkMetadata(compressedOffset, decompressedOffset);
ChunkList.Add(chunk);
}
}
catch (WrongSourceFileException ex)
{
throw new WrongSourceFileException(ex.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// Using to compress
/// </summary>
internal Metadata(string source, long sourceSize)
{
_magicWordBytes = Encoding.UTF8.GetBytes(_magicWord);
FileExtension = Helper.GetFileExtension(source);
MetadataSize = _magicWordBytes.Length
+ sizeof(int)
+ 8
+ (int)Math.Ceiling((double)sourceSize / Settings.ChunkSizeBytes) * ChunkMetadata.SizeOf();
}
