/// <summary>
/// Returns a random string, conforming to the provided regular expression pattern.
/// </summary>
/// <param name="regex">The regular expression, which the generated string should conform to.</param>
/// <param name="seed">The random number generator seed.</param>
/// <returns>A string, conforming to the provided regular expression pattern.</returns>
///
/// <example>
/// The following example demonstrates how to generate a random string from a Regex pattern:
/// <code lang="C#" >
/// // Using a custom regex pattern...
/// Regex emailAddress1 = new Regex(@"^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$");
/// string s1 = StringFactory.GenerateRandomString(emailAddress1, 1234);
///
/// // Using a standard regex pattern...
/// Regex emailAddress2 = CommonRegexPatterns.EmailAddress;
/// string s2 = StringFactory.GenerateRandomString(emailAddress2, 1234);
/// </code>
/// </example>
public static string GenerateRandomString(Regex regex, int seed)
{
Random random = new Random(seed);
//reset the static variables
RegexCompiler.IsInvalidSection = false;
RegexCompiler.InvalidNode = null;
RegexCompiler.InvalidableNodes.Clear();
//construct the RegEx tree
RegexCompiler compiler = new RegexCompiler();
RegexNode node = compiler.Compile(regex.ToString());
//search for a signal to invalidate a node
if (regex.ToString().IndexOf("\\i") != -1)
{
//something should have been invalidated
//select a node to invalidate
if (RegexCompiler.InvalidableNodes.Count == 0)
{
throw new ArgumentException("Asked to generate invalid: Impossible to invalidate");
}
RegexCompiler.InvalidNode = RegexCompiler.InvalidableNodes[random.Next(RegexCompiler.InvalidableNodes.Count)];
//Mark REOrNodes and RERepeatNodes to ensure that the invalid node will be part of the string
RegexCompiler.InvalidNode.ReservePath(null);
}
//generate and return the string
string result = node.Generate(random);
if (RegexCompiler.InvalidNode != null)
{
//confirm that the generated string is invalid (e.g. [a-z]|[^a-z] will always fail)
Regex compare = new Regex("^" + regex.Replace("\\i", "") + "$");
if (compare.IsMatch(result))
{
throw new ArgumentException(regex + ": Did not generate invalid string: " + result);
}
}
return(result);
}
//Compile [:alpha:] [:punct:] etc
public RegexNode CompileMacro(int index, int len)
{
AssertParse(len >= 0, "Cannot parse macro.");
string substr = mRegex.ToString().Substring(index, len);
string expanded = null;
switch (substr)
{
case "alnum": expanded = "[a-zA-Z0-9]"; break;
case "alpha": expanded = "[a-zA-Z]"; break;
case "upper": expanded = "[A-Z]"; break;
case "lower": expanded = "[a-z]"; break;
case "digit": expanded = "[0-9]"; break;
case "xdigit": expanded = "[A-F0-9a-f]"; break;
case "space": expanded = "[ \t]"; break;
case "print": expanded = "[\\x20-\\x7F]"; break;
case "punct": expanded = "[,;.!'\"]"; break;
case "graph": expanded = "[\\x80-\\xFF]"; break;
case "cntrl": expanded = "[\x00-\x1F\x7F]"; break;
case "blank": expanded = "[ \t\r\n\f]"; break;
case "guid": expanded = "[A-F0-9]{8}(-[A-F0-9]{4}){3}-[A-F0-9]{12}"; break;
default: AssertParse(false, "Cannot parse macro."); break;
}
RegexCompiler subcompiler = new RegexCompiler();
return(subcompiler.Compile(expanded));
}
