/// <summary>
/// Tries to read a buffer and parse out an IRC statement.
/// </summary>
/// <param name="buffer">The buffer to read from.</param>
/// <param name="offset">The offset to begin reading. The parser may advance this, even if parsing fails.</param>
/// <param name="count">The maximum number of bytes to read.</param>
/// <param name="statement">The statement, if parsing succeeds, or <c>null</c>.</param>
/// <returns><c>true</c> if parsing succeeded.</returns>
public static bool TryParse(byte[] buffer, ref int offset, int count,
out IrcStatement statement)
{
IrcStatementParseResult parseResult;
return(TryParse(buffer, ref offset, count, out statement, out parseResult));
}
bool TryReceiveFromBuffer(out IrcStatement statement, out IrcStatementParseResult parseResult)
{
int offset = 0;
bool gotStatement = IrcStatement.TryParse(_buffer, ref offset, _count, out statement, out parseResult);
Debug.Assert(offset <= _count);
if (offset != 0)
{
Array.Copy(_buffer, offset, _buffer, 0, _count - offset); _count -= offset;
}
return(gotStatement);
}
internal static bool ValidateStatement(IrcStatement statement, out string errorMessage)
{
errorMessage = null;
if (statement.Source != null && !ValidateIdentity(statement.Source, out errorMessage))
{
return(false);
}
if (statement.Command == null)
{
errorMessage = "Command is not set."; return(false);
}
if (statement.Command.Length == 3 && statement.Command.All(x => x >= (byte)'0' && x <= (byte)'9'))
{
// Command is a number.
}
else if (statement.Command.Length > 0 && statement.Command.All(x => x >= (byte)'A' && x <= (byte)'Z'))
{
// Command is letters.
}
else
{
errorMessage = "Command is invalid."; return(false);
}
if (statement.Parameters.Count > IrcConstants.MaxParameters)
{
errorMessage = string.Format("IRC only allows up to {0} parameters.", IrcConstants.MaxParameters);
return(false);
}
for (int i = 0; i < statement.Parameters.Count; i++)
{
var parameter = statement.Parameters[i];
if (parameter == null)
{
errorMessage = "No parameters may be null."; return(false);
}
if (!ValidateParameter(parameter, i == statement.Parameters.Count - 1, out errorMessage))
{
return(false);
}
}
return(true);
}
/// <summary>
/// Tries to receive an IRC statement.
///
/// A blocking read is used.
/// If you have a timeout set, <paramref name="parseResult"/> may be <see cref="IrcStatementParseResult.TimedOut"/>.
/// </summary>
/// <param name="statement">The statement.</param>
/// <param name="parseResult">The parse result.</param>
/// <returns><c>true</c> if a complete IRC statement was received.</returns>
public bool TryReceive(out IrcStatement statement, out IrcStatementParseResult parseResult)
{
if (TryReceiveFromBuffer(out statement, out parseResult))
{
return(true);
}
var receiveResult = TryReceiveFromStream();
if (receiveResult != IrcStatementParseResult.OK)
{
statement = null; parseResult = receiveResult;
return(false);
}
return(TryReceiveFromBuffer(out statement, out parseResult));
}
/// <summary>
/// Tries to read a buffer and parse out an IRC statement.
/// Additionally, on failure, the reason for failure is returned.
/// </summary>
/// <param name="buffer">The buffer to read from.</param>
/// <param name="offset">The offset to begin reading. The parser may advance this, even if parsing fails.</param>
/// <param name="count">The maximum number of bytes to read.</param>
/// <param name="statement">The statement, if parsing succeeds, or <c>null</c>.</param>
/// <param name="parseResult">The result of parsing. On failure, this is the reason for the failure.</param>
/// <returns><c>true</c> if parsing succeeded.</returns>
public static bool TryParse(byte[] buffer, ref int offset, int count,
out IrcStatement statement, out IrcStatementParseResult parseResult)
{
Throw.If.Null(buffer, "buffer");
string errorMessage = null;
IrcString[] parts;
statement = null; parseResult = IrcStatementParseResult.NothingToParse;
// First, skip all initial CR/LF.
SkipCrlf(buffer, ref offset, ref count);
// See if we've got a CR or LF anywhere.
int crlfIndex = IrcString.IndexOf(buffer, @byte => @byte == 13 || @byte == 10, offset, count);
if (crlfIndex == -1)
{
if (count >= IrcConstants.MaxStatementLength)
{
parseResult = IrcStatementParseResult.StatementTooLong;
}
return(false);
}
// OK, let's get our string.
var @string = new IrcString(buffer, offset, crlfIndex - offset);
#if DEBUG
var debugString = @string;
#endif
offset += @string.Length + 1; count -= @string.Length + 1;
SkipCrlf(buffer, ref offset, ref count);
if (crlfIndex >= IrcConstants.MaxStatementLength)
{
parseResult = IrcStatementParseResult.StatementTooLong; return(false);
}
// Do we have a prefix?
statement = new IrcStatement();
if (@string.Length >= 1 && @string[0] == (byte)':')
{
parts = @string.Split((byte)' ', 2);
var sourceString = parts[0].Substring(1); IrcIdentity source;
if (!IrcIdentity.TryParse(sourceString, out source))
{
goto invalid;
}
statement.Source = source;
@string = parts.Length >= 2 ? parts[1] : IrcString.Empty;
}
// Now get the command.
parts = @string.Split((byte)' ', 2);
statement.Command = parts[0];
@string = parts.Length >= 2 ? parts[1] : IrcString.Empty;
// Parameters, now...
while (@string.Length > 0)
{
if (@string[0] == (byte)':')
{
statement.Parameters.Add(@string.Substring(1));
break;
}
else
{
parts = @string.Split((byte)' ', 2);
statement.Parameters.Add(parts[0]);
if (parts.Length == 1)
{
break;
}
@string = parts[1];
}
}
// We're done. If everything's kosher, we'll return true.
if (!IrcValidation.ValidateStatement(statement, out errorMessage))
{
goto invalid;
}
parseResult = IrcStatementParseResult.OK;
return(true);
invalid:
#if DEBUG
Console.WriteLine("Invalid statement '{0}' (error '{1}').", debugString, errorMessage);
#endif
statement = null; parseResult = IrcStatementParseResult.InvalidStatement;
return(false);
}