CommandLineParser about weihanli.common HOT 2 CLOSED

public static IEnumerable<string> ParseLine(string line)
{
    if (string.IsNullOrEmpty(line))
    {
        yield break;
    }

    var tokenBuilder = new StringBuilder();

    var inToken= false;
    var inQuotes = false;

    // Iterate through every character in the line
    for (var i = 0; i < line.Length; i++)
    {
        var character = line[i];

        // If we are not currently inside a column
        if (!inToken)
        {
            // If the current character is a quote then the token value is contained within
            // quotes, otherwise append the next character
            inToken = true;
            if (character == '\'')
            {
                inQuotes = true;
                continue;
            }
        }

        // If we are in between quotes
        if (inQuotes)
        {
            if (i + 1 == line.Length)
            {
                break;
            }

            if (character == '\'' && line[i + 1] == ' ') // quotes end
            {
                inQuotes = false;
                inToken = false;
                i++; //skip next
            }
            else if (character == '\'' && line[i + 1] == '\'') // quotes
            {
                i++; //skip next
            }
            else if (character == '\'')
            {
                throw new ArgumentException($"unable to escape {line}");
            }
        }
        else if (character == ' ')
        {
            inToken = false;
        }

        // If we are no longer in the token clear the builder and add the columns to the list
        if (!inToken)
        {
            if (tokenBuilder.Length > 0)
            {
                yield return tokenBuilder.ToString();
                tokenBuilder.Clear();
            }
        }
        else
        {
            tokenBuilder.Append(character);
        }
    }

    if (tokenBuilder.Length > 0)
    {
        yield return tokenBuilder.ToString();
        tokenBuilder.Clear();
    }
}