/// <summary>
/// UrlDecodes a string except chars forbidden in Windows filepaths
/// </summary>
public static string DecodeURLForFilepath(this string url)
{
if (url == null)
{
return(null);
}
int length = url.Length;
UrlDecoder decoder = new UrlDecoder(length * 10, Encoding.UTF8);
decoder.forFilePaths = true;
// per char
for (int i = 0; i < length; i++)
{
char ch = url[i];
// PLUS char converts to SPACE
if (ch == '+')
{
ch = ' ';
// SPECIAL chars encoded in "%20" format
}
else if ((ch == '%') && (i < (length - 2)))
{
// unicode char (4 digit hex)
if ((url[i + 1] == 'u') && (i < (length - 5)))
{
int num3 = HexToInt(url[i + 2]);
int num4 = HexToInt(url[i + 3]);
int num5 = HexToInt(url[i + 4]);
int num6 = HexToInt(url[i + 5]);
if (((num3 < 0) || (num4 < 0)) || ((num5 < 0) || (num6 < 0)))
{
goto Label_010B;
}
ch = (char)((((num3 << 12) | (num4 << 8)) | (num5 << 4)) | num6);
i += 5;
decoder.FlushBytes(false); // dont check previous stuff
decoder.AddChar(ch, true); // CHECK IF CHAR OK WITH FILEPATH
continue;
}
// ascii char (2 digit hex)
int num7 = HexToInt(url[i + 1]);
int num8 = HexToInt(url[i + 2]);
if ((num7 >= 0) && (num8 >= 0))
{
byte b = (byte)((num7 << 4) | num8);
i += 2;
decoder.FlushBytes(false); // dont check previous stuff
decoder.AddByte(b);
// check if unicode char ("%11%11")
if (((i + 1) < (length - 2)) && (url[i + 1] == '%'))
{
// YES, unicode char
num7 = HexToInt(url[i + 1]);
num8 = HexToInt(url[i + 2]);
if ((num7 >= 0) && (num8 >= 0))
{
b = (byte)((num7 << 4) | num8);
i += 2;
decoder.AddByte(b);
decoder.FlushBytes(true); // CHECK IF CHARS OK WITH FILEPATHS
}
}
else
{
// NO, not unicode char
decoder.FlushBytes(true); // CHECK IF CHARS OK WITH FILEPATHS
}
continue;
}
}
Label_010B:
if ((ch & 0xff80) == 0)
{
decoder.AddByte((byte)ch);
}
else
{
decoder.AddChar(ch, false);
}
}
return(decoder.GetString());
}