internal static ExtendedTagHeaderV4 Create(bool updateFlag, bool crcPresent, bool restrictionPresent,
byte restriction, ReadOnlyCollection<byte> crc32)
{
var extendedHeader = new ExtendedTagHeaderV4();
extendedHeader.UpdateTag = updateFlag;
extendedHeader.CrcDataPresent = crcPresent;
extendedHeader.RestrictionPresent = restrictionPresent;
extendedHeader.Restriction = restriction;
extendedHeader.Crc32 = crc32;
return extendedHeader;
}
internal static ExtendedTagHeaderV4 Create(byte[] content)
{
var extendedHeader = new ExtendedTagHeaderV4();
// ignore content[0] ( always 01 )
byte flagByte = content[1];
bool updateFlag = (flagByte & 0x40) == 0x40;
bool crc32Flag = (flagByte & 0x20) == 0x020;
bool restrictionFlag = (flagByte & 0x10) == 0x10;
int startIndex = 2;
if (updateFlag)
{
// Read the update content
//TODO: The length is always 0. hm... better implementation here?
//var length = content[startIndex];
startIndex++;
extendedHeader.UpdateTag = true;
}
if (crc32Flag)
{
// Read the crc32
var crcBytes = new byte[5];
Array.Copy(content, startIndex + 1, crcBytes, 0, 5);
startIndex += 6;
extendedHeader.CrcDataPresent = true;
extendedHeader.Crc32 = new ReadOnlyCollection<byte>(crcBytes);
}
if (restrictionFlag)
{
// Read the restriction byte
byte restrictionByte = content[startIndex + 1];
extendedHeader.RestrictionPresent = true;
extendedHeader.Restriction = restrictionByte;
}
return extendedHeader;
}