/// <summary>
/// Gets the underlying buffer position for a StreamReader.
/// </summary>
///
/// <param name="reader">A StreamReader whose position will be retrieved.</param>
///
/// <returns>The current offset from the beginning of the
/// file that the StreamReader is currently located into.</returns>
///
public static long GetPosition(this StreamReader reader)
{
// http://stackoverflow.com/a/17457085/262032
#if NETSTANDARD1_4 || NETSTANDARD2_0
var type = typeof(StreamReader).GetTypeInfo();
char[] charBuffer = (char[])type.GetDeclaredField("_charBuffer").GetValue(reader);
int charPos = (int)type.GetDeclaredField("_charPos").GetValue(reader);
int byteLen = (int)type.GetDeclaredField("_byteLen").GetValue(reader);
#else
var type = typeof(StreamReader);
char[] charBuffer;
int charPos;
int byteLen;
if (SystemTools.IsRunningOnMono() && type.GetField("decoded_buffer") != null)
{
// Mono's StreamReader source code is at: https://searchcode.com/codesearch/view/26576619/
// The current buffer of decoded characters
charBuffer = (char[])GetField(reader, "decoded_buffer");
// The current position in the buffer of decoded characters
charPos = (int)GetField(reader, "decoded_count");
// The number of encoded bytes that are in the current buffer
byteLen = (int)GetField(reader, "buffer_size");
}
else
{
// The current buffer of decoded characters
charBuffer = (char[])GetField(reader, "charBuffer");
// The current position in the buffer of decoded characters
charPos = (int)GetField(reader, "charPos");
// The number of encoded bytes that are in the current buffer
byteLen = (int)GetField(reader, "byteLen");
}
#endif
// The number of bytes that the already-read characters need when encoded.
int numReadBytes = reader.CurrentEncoding.GetByteCount(charBuffer, 0, charPos);
return(reader.BaseStream.Position - byteLen + numReadBytes);
}
/// <summary>
/// Populates the dictionary with available decoders of a particular category by
/// inspecting types from all referenced assemblies. Note: calling this method
/// will force all referenced assemblies to be loaded into the current AppDomain.
/// </summary>
///
/// <typeparam name="T">The base type for the decoders. This should be an interface such as IImageDecoder or IAudioDecoder.</typeparam>
///
/// <param name="dictionary">The dictionary where the found decoders will be stored.</param>
/// <param name="extension">The extension we are interested in.</param>
///
public static void PopulateDictionaryWithDecodersFromAllAssemblies <T>(Dictionary <string, Type> dictionary, string extension)
{
lock (dictionary)
{
extension = extension.ToUpperInvariant();
if (dictionary.ContainsKey(extension))
{
return;
}
var decoderTypes = new List <Tuple <Type, FormatDecoderAttribute[]> >();
#if NETSTANDARD1_4
TypeInfo baseType = typeof(T).GetTypeInfo();
foreach (Type t in baseType.Assembly.ExportedTypes)
{
TypeInfo ti = t.GetTypeInfo();
var attributes = ti.GetCustomAttributes(typeof(FormatDecoderAttribute), true).ToArray();
if (attributes != null && attributes.Length > 0 && baseType.IsAssignableFrom(ti))
{
FormatDecoderAttribute[] at = attributes.Cast <FormatDecoderAttribute>().ToArray();
decoderTypes.Add(Tuple.Create(t, at));
}
}
#else
Type baseType = typeof(T);
if (SystemTools.IsRunningOnMono())
{
Console.WriteLine("FormatDecoderAttribute: Running on Mono ({0})", typeof(T));
foreach (Assembly a in AppDomain.CurrentDomain.GetAssemblies())
{
foreach (Type t in a.GetTypes())
{
var attributes = t.GetCustomAttributes(typeof(FormatDecoderAttribute), true);
if (attributes != null && attributes.Length > 0 && baseType.IsAssignableFrom(t))
{
FormatDecoderAttribute[] at = attributes.Cast <FormatDecoderAttribute>().ToArray();
decoderTypes.Add(Tuple.Create(t, at));
}
}
}
Console.WriteLine("FormatDecoderAttribute: Found {0} {1} decoders.", decoderTypes.Count, typeof(T));
}
else
{
foreach (Assembly a in AppDomain.CurrentDomain.GetAssemblies())
{
foreach (AssemblyName referencedName in a.GetReferencedAssemblies())
{
Assembly referencedAssembly = Assembly.Load(referencedName);
foreach (Type t in referencedAssembly.GetTypes())
{
var attributes = t.GetCustomAttributes(typeof(FormatDecoderAttribute), true);
if (attributes != null && attributes.Length > 0 && baseType.IsAssignableFrom(t))
{
FormatDecoderAttribute[] at = attributes.Cast <FormatDecoderAttribute>().ToArray();
decoderTypes.Add(Tuple.Create(t, at));
}
}
}
}
}
#endif
foreach (Tuple <Type, FormatDecoderAttribute[]> pair in decoderTypes)
{
foreach (FormatDecoderAttribute attr in pair.Item2)
{
extension = attr.Extension.ToUpperInvariant();
if (!dictionary.ContainsKey(extension))
{
dictionary.Add(extension, pair.Item1);
}
}
}
}
}
