// Converts %XX and %uYYYY to the actual characters (I.e. Unesacpes any escape characters present in the URL)
private String UnescapeURL(String url)
{
StringBuilder intermediate = StringBuilderCache.Acquire(url.Length);
int Rindex = 0; // index into temp that gives the rest of the string to be processed
int index;
int braIndex = -1;
int ketIndex = -1;
braIndex = url.IndexOf('[', Rindex);
if (braIndex != -1)
{
ketIndex = url.IndexOf(']', braIndex);
}
do
{
index = url.IndexOf('%', Rindex);
if (index == -1)
{
intermediate = intermediate.Append(url, Rindex, (url.Length - Rindex));
break;
}
// if we hit a '%' in the middle of an IPv6 address, dont process that
if (index > braIndex && index < ketIndex)
{
intermediate = intermediate.Append(url, Rindex, (ketIndex - Rindex + 1));
Rindex = ketIndex + 1;
continue;
}
if (url.Length - index < 2) // Check that there is at least 1 char after the '%'
{
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidUrl"));
}
if (url[index + 1] == 'u' || url[index + 1] == 'U')
{
if (url.Length - index < 6) // example: "%u004d" is 6 chars long
{
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidUrl"));
}
// We have a unicode character specified in hex
try
{
char c = (char)(Hex.ConvertHexDigit(url[index + 2]) << 12 |
Hex.ConvertHexDigit(url[index + 3]) << 8 |
Hex.ConvertHexDigit(url[index + 4]) << 4 |
Hex.ConvertHexDigit(url[index + 5]));
intermediate = intermediate.Append(url, Rindex, index - Rindex);
intermediate = intermediate.Append(c);
}
catch (ArgumentException) // Hex.ConvertHexDigit can throw an "out of range" ArgumentException
{
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidUrl"));
}
Rindex = index + 6; //update the 'seen' length
}
else
{
// we have a hex character.
if (url.Length - index < 3) // example: "%4d" is 3 chars long
{
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidUrl"));
}
try
{
char c = (char)(Hex.ConvertHexDigit(url[index + 1]) << 4 | Hex.ConvertHexDigit(url[index + 2]));
intermediate = intermediate.Append(url, Rindex, index - Rindex);
intermediate = intermediate.Append(c);
}
catch (ArgumentException) // Hex.ConvertHexDigit can throw an "out of range" ArgumentException
{
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidUrl"));
}
Rindex = index + 3; // update the 'seen' length
}
}while (true);
return(StringBuilderCache.GetStringAndRelease(intermediate));
}