public IEnumerable <string> PatternMatches(string str, List <string> keywords)
{
var stack = new Stack <Tuple <int, int, IEnumerable <string> > >();
stack.Push(new Tuple <int, int, IEnumerable <string> >(0, 0, new List <string>()));
while (stack.Any())
{
var temp = stack.Pop();
if (temp.Item1 >= str.Length)
{
return(temp.Item3);
}
if (temp.Item2 >= keywords.Count)
{
continue;
}
var keyword = keywords[temp.Item2];
if (!keyword.IsPattern())
{
if (str.StartsWith(temp.Item1, keyword))
{
stack.Push(new Tuple <int, int, IEnumerable <string> >(temp.Item1 + keyword.Length, temp.Item2 + 1, temp.Item3.Append(keyword)));
}
}
else
{
if (PatternToPhrases.TryGetValue(keyword, out var phrases))
{
foreach (var phrase in phrases)
{
if (str.StartsWith(temp.Item1, phrase))
{
stack.Push(new Tuple <int, int, IEnumerable <string> >(temp.Item1 + phrase.Length, temp.Item2 + 1, temp.Item3.Append(phrase)));
}
}
}
}
}
return(new List <string>());
}
/// <summary>
/// Add matching rule
/// </summary>
/// <param name="matchingRuleItem"></param>
public void Add(MatchingRuleItem matchingRuleItem)
{
var keywords = matchingRuleItem.KeyWords.SplitPatterns().ToList();
switch (matchingRuleItem.Type)
{
case MatchingRuleType.Perfect:
var key = keywords.First();
if (!key.IsPattern())
{
if (!Perfect.TryGetValue(key, out var list))
{
list = new List <MatchingRuleItem>();
Perfect[key] = list;
}
list.Add(matchingRuleItem);
}
else if (PatternToPhrases.TryGetValue(key, out var phrases))
{
foreach (var phrase in phrases)
{
if (!Perfect.TryGetValue(phrase, out var list))
{
list = new List <MatchingRuleItem>();
Perfect[phrase] = list;
}
list.Add(matchingRuleItem);
}
}
else
{
throw new KeyNotFoundException($"Pattern={key} is not found");
}
break;
case MatchingRuleType.Pattern:
case MatchingRuleType.Contain:
var indexKeyWord = keywords.First();
foreach (var keyword in keywords.Skip(1))
{
if (!keyword.IsPattern())
{
if (indexKeyWord.IsPattern())
{
indexKeyWord = keyword;
}
else
{
if (indexKeyWord.Length < keyword.Length)
{
indexKeyWord = keyword;
}
}
}
}
if (!indexKeyWord.IsPattern())
{
var indexKey = indexKeyWord.Substring(0, Math.Min(indexKeyWord.Length, MaxIndexLen));
if (!RuleItems.TryGetValue(indexKey, out var containRuleItems))
{
containRuleItems = new List <MatchingRuleItem>();
RuleItems[indexKey] = containRuleItems;
}
containRuleItems.Add(matchingRuleItem);
}
else if (PatternToPhrases.TryGetValue(indexKeyWord, out var phrases))
{
foreach (var phrase in phrases)
{
var indexKey = phrase.Substring(0, Math.Min(phrase.Length, MaxIndexLen));
if (!RuleItems.TryGetValue(indexKey, out var list))
{
list = new List <MatchingRuleItem>();
RuleItems[indexKey] = list;
}
list.Add(matchingRuleItem);
}
}
else
{
throw new KeyNotFoundException($"Pattern={indexKeyWord} is not found");
}
break;
}
}
/// <summary>
/// Retrieve all rules that match this string
/// </summary>
/// <param name="str">input string</param>
/// <returns>list of rule items</returns>
public List <MatchingRuleOutput> Retrieve(string str)
{
if (string.IsNullOrEmpty(str))
{
throw new ArgumentNullException(nameof(str));
}
if (Perfect.TryGetValue(str, out var ret))
{
return(ret.ToRuleOutputs());
}
// Fetch rule candidates
var candidates = new List <MatchingRuleItem>();
for (var i = 0; i < str.Length; i++)
{
for (var j = 0; j < Math.Min(MaxIndexLen, str.Length - i); j++)
{
var key = str.Substring(i, j + 1);
if (RuleItems.TryGetValue(key, out var rules))
{
candidates.AddRange(rules);
}
}
}
candidates = candidates.OrderBy(x => { return(x.Type == MatchingRuleType.Pattern ? 0 : 1); }).ToList();
// Further check if rule matches or not
var matches = new List <MatchingRuleOutput>();
foreach (var candidate in candidates)
{
var keywords = candidate.KeyWords.SplitPatterns().ToList();
switch (candidate.Type)
{
case MatchingRuleType.Contain:
var patternMatches1 = keywords.Select(keyword =>
{
if (!keyword.IsPattern())
{
return(str.Contains(keyword) ? keyword : null);
}
else if (PatternToPhrases.TryGetValue(keyword, out var phrases))
{
return(phrases.FirstOrDefault(x => str.Contains(x)));
}
return(null);
});
if (!patternMatches1.Any(x => x == null))
{
matches.Add(candidate.ToRuleOutput(patternMatches1));
}
break;
case MatchingRuleType.Pattern:
var patternMatches2 = PatternMatches(str, keywords);
if (patternMatches2.Any())
{
matches.Add(candidate.ToRuleOutput(patternMatches2));
}
break;
default:
break;
}
}
return(matches);
}