/// <summary>
/// Gets the header attributes for the given <paramref name="headerName"/>
/// using the information from the given <paramref name="attribute"/>.
/// This adds the header to the list of container headers if-and-only-if the
/// header is a container header.
/// </summary>
/// <param name="headerName">the header name</param>
/// <param name="attribute">the attribute for the given header name</param>
/// <param name="allContainerHeaders">the list of all container headers</param>
/// <returns>the header attributes</returns>
private static HeaderAttributes GetHeaderAttributes(Mpeg4HeaderName headerName, Mpeg4Attribute attribute, ICollection <Mpeg4HeaderName> allContainerHeaders)
{
// Retrieve list of header start codes
List <uint> headerStartCodes = new List <uint>();
if (attribute.HeaderStartCode != null)
{
const string SeparatorCharacter = "-";
if (attribute.HeaderStartCode.Contains(SeparatorCharacter))
{
Debug.Assert(attribute.HeaderStartCode.Length == 5); // Example: "40-5F"
string[] startCodes = attribute.HeaderStartCode.Split(SeparatorCharacter.ToCharArray());
uint firstStartCode = uint.Parse(startCodes[0], System.Globalization.NumberStyles.HexNumber, CultureInfo.InvariantCulture);
uint lastStartCode = uint.Parse(startCodes[1], System.Globalization.NumberStyles.HexNumber, CultureInfo.InvariantCulture);
Debug.Assert(firstStartCode < lastStartCode);
for (uint startCode = firstStartCode; startCode <= lastStartCode; startCode++)
{
headerStartCodes.Add(0x100 + startCode);
}
}
else
{
headerStartCodes.Add(0x100 + uint.Parse(attribute.HeaderStartCode, System.Globalization.NumberStyles.HexNumber, CultureInfo.InvariantCulture));
}
}
// Retrieve suitable parents, all container headers if empty list
ICollection <Mpeg4HeaderName> suitableParents = attribute.SuitableParents;
if (suitableParents.Count == 0)
{
suitableParents = allContainerHeaders;
}
// Update list of all container headers
if ((attribute.HeaderFlags & HeaderFlags.MasterHeader) == HeaderFlags.MasterHeader)
{
allContainerHeaders.Add(headerName);
}
return(new HeaderAttributes(headerStartCodes.AsReadOnly(), attribute.HeaderFlags, suitableParents));
}
/// <summary>
/// Gets the suitable parents for the given <paramref name="headerName"/>.
/// </summary>
/// <param name="headerName">the header name</param>
/// <returns>the suitable parents</returns>
public static ICollection <Mpeg4HeaderName> GetSuitableParents(this Mpeg4HeaderName headerName)
{
return(_headerAttributes[headerName].SuitableParents);
}
/// <summary>
/// Returns whether the given <paramref name="chunkName"/> is a top-level chunk type.
/// Top-level chunks are only allowed in the root. For example, the Movie chunk.
/// </summary>
/// <param name="chunkName">the chunk name</param>
/// <returns>true if it is a top-level chunk type, false otherwise</returns>
public static bool IsTopLevel(this Mpeg4HeaderName chunkName)
{
ICollection <Mpeg4HeaderName> suitableParents = chunkName.GetSuitableParents();
return(suitableParents.Count == 1 && suitableParents.Contains(Mpeg4HeaderName.Root));
}
/// <summary>
/// Gets the header flags for the given <paramref name="headerName"/>.
/// </summary>
/// <param name="headerName">the header name</param>
/// <returns>the header flags</returns>
public static HeaderFlags GetHeaderFlags(this Mpeg4HeaderName headerName)
{
return(_headerAttributes[headerName].HeaderFlags);
}
/// <summary>
/// Returns whether the given <paramref name="headerFlag"/> is set for
/// the given <paramref name="headerName"/>.
/// </summary>
/// <param name="headerName">the header name</param>
/// <param name="headerFlag">the flag to test</param>
/// <returns>true if the flag is set, false otherwise</returns>
public static bool IsFlagSet(this Mpeg4HeaderName headerName, HeaderFlags headerFlag)
{
return((headerName.GetHeaderFlags() & headerFlag) == headerFlag);
}
