/// <summary>Examines the a file's first bytes and estimates the file's type.</summary>
/// <exception cref="ArgumentException">Stream does not support seeking.</exception>
/// <exception cref="IOException">if an IO error occurred or the input stream ended unexpectedly.</exception>
public static FileType DetectFileType([NotNull] Stream stream)
{
if (!stream.CanSeek)
{
throw new ArgumentException("Must support seek", nameof(stream));
}
var maxByteCount = _root.MaxDepth;
var bytes = new byte[maxByteCount];
var bytesRead = stream.Read(bytes, 0, bytes.Length);
if (bytesRead == 0)
{
return(FileType.Unknown);
}
stream.Seek(-bytesRead, SeekOrigin.Current);
var fileType = _root.Find(bytes);
if (fileType == FileType.Unknown)
{
foreach (var fixedChecker in _fixedCheckers)
{
fileType = fixedChecker(bytes);
if (fileType != FileType.Unknown)
{
return(fileType);
}
}
}
return(fileType);
}
/// <summary>Examines the a file's first bytes and estimates the file's type.</summary>
/// <exception cref="ArgumentException">Stream does not support seeking.</exception>
/// <exception cref="IOException">An IO error occurred, or the input stream ended unexpectedly.</exception>
public static FileType DetectFileType([NotNull] Stream stream)
{
if (!stream.CanSeek)
{
throw new ArgumentException("Must support seek", nameof(stream));
}
var maxByteCount = _root.MaxDepth;
var bytes = new byte[maxByteCount];
var bytesRead = stream.Read(bytes, 0, bytes.Length);
if (bytesRead == 0)
{
return(FileType.Unknown);
}
stream.Seek(-bytesRead, SeekOrigin.Current);
var fileType = _root.Find(bytes);
if (fileType == FileType.Unknown)
{
foreach (var fixedChecker in _fixedCheckers)
{
fileType = fixedChecker(bytes);
if (fileType != FileType.Unknown)
{
return(fileType);
}
}
}
else if (fileType == FileType.Riff)
{
var fourCC = Encoding.UTF8.GetString(bytes, index: 8, count: 4);
switch (fourCC)
{
case "WAVE":
return(FileType.Wav);
case "AVI ":
return(FileType.Avi);
case "WEBP":
return(FileType.WebP);
}
}
return(fileType);
}