private static bool SpecialParseValue(ExifId id, ExifDataType type, byte[] data, out object temp)
{
temp = null;
switch (id)
{
// Convert to DateTime
case ExifId.ImageDateTime:
case ExifId.ImageDateTimeOriginal:
case ExifId.ImagePreviewDateTime:
case ExifId.PhotoDateTimeDigitized:
//case ExifId.PhotoDateTimeOriginal: // Same value as ImageDateTimeOriginal
case ExifId.ThumbnailDateTime:
string datestring = Encoding.ASCII.GetString(data).RemoveNullChars();
DateTime datetime;
if (DateTime.TryParse(datestring, out datetime))
{
temp = datetime;
return true;
}
// Handle special cases
if (DateTime.TryParseExact(datestring, "yyyy:MM:dd HH:mm:ss", CultureInfo.InvariantCulture, DateTimeStyles.None, out datetime))
{
temp = datetime;
return true;
}
return false;
// Convert to UCS-2
case ExifId.ImageXPAuthor:
case ExifId.ImageXPComment:
case ExifId.ImageXPSubject:
case ExifId.ImageXPTitle:
temp = Encoding.GetEncoding("ucs-2").GetString(data).RemoveNullChars();
return true;
case ExifId.ImageXPKeywords:
string keywords = Encoding.GetEncoding("ucs-2").GetString(data).RemoveNullChars();
if (keywords.Length > 0)
temp = keywords.Split(new char[] { TagsSeparator }, StringSplitOptions.RemoveEmptyEntries);
else
temp = new string[0];
return true;
default:
return false;
}
}
private static object ParseValue(ExifId id, ExifDataType type, byte[] data)
{
if (type != ExifDataType.Binary && type != ExifDataType.Undefined)
{
if (data == null)
throw new ArgumentNullException(nameof(data), String.Format("ID: {0}. Type: {1}.", id, type));
}
object temp;
if (SpecialParseValue(id, type, data, out temp))
return temp;
switch (type)
{
case ExifDataType.Binary:
return data;
case ExifDataType.ASCII:
return Encoding.ASCII.GetString(data).RemoveNullChars();
case ExifDataType.Int16:
return BitConverter.ToInt16(data, 0);
case ExifDataType.Int32:
return BitConverter.ToInt32(data, 0);
case ExifDataType.Long:
return BitConverter.ToInt64(data, 0);
case ExifDataType.Float:
case ExifDataType.Double:
return (double)BitConverter.ToInt32(data, 0) / (double)BitConverter.ToInt32(data, 4);
case ExifDataType.Undefined:
return data;
default:
throw new NotImplementedException(String.Format("Type not implemented: {0}", type));
}
}
