/// <summary>
/// Searches the specified text and determines if it contains any occurrence of any keyword.
/// </summary>
/// <param name="text">The text to search.</param>
/// <param name="startIndex">The search starting position.</param>
/// <returns>
/// <c>true</c> if the text searched contains any occurrence of any keyword; otherwise, <c>false</c>.
/// </returns>
public bool ContainsAny(string text, int startIndex = 0)
{
InnerNode ptr = _root;
while (startIndex < text.Length)
{
InnerNode trans = null;
while (trans == null)
{
trans = ptr.GetTransition(text[startIndex]);
if (ptr == _root)
{
break;
}
if (trans == null)
{
ptr = ptr._failure;
}
}
if (trans != null)
{
ptr = trans;
}
if (ptr._results.Count > 0)
{
return(true);
}
++startIndex;
}
return(false);
}
/// <summary>
/// Searches the specified text and returns all occurrences of any keyword.
/// </summary>
/// <param name="text">The text to search.</param>
/// <param name="startIndex">The search starting position.</param>
/// <returns>
/// An array of <see cref="StringSearchResult" /> objects that store the search result; null if the search fails.
/// </returns>
public StringSearchResult[] FindAll(string text, int startIndex = 0)
{
var rlt = new List <StringSearchResult>();
InnerNode ptr = _root;
while (startIndex < text.Length)
{
InnerNode trans = null;
while (trans == null)
{
trans = ptr.GetTransition(text[startIndex]);
if (ptr == _root)
{
break;
}
if (trans == null)
{
ptr = ptr._failure;
}
}
if (trans != null)
{
ptr = trans;
}
foreach (var found in ptr._results)
{
rlt.Add(new StringSearchResult()
{
Position = startIndex - found.Key.Length + 1,
Value = found.Key,
HitIndex = found.Value
});
}
++startIndex;
}
if (rlt.Count == 0)
{
return(null);
}
return(rlt.ToArray());
}
void _buildTree(string[] keywords)
{
//build keyword tree and transition function
_root = new InnerNode(null, ' ');
var keywordCount = keywords.Length;
for (int i = 0; i < keywordCount; ++i)
{
var p = keywords[i];
// add pattern to tree
InnerNode nd = _root;
foreach (var c in p)
{
InnerNode ndNew = null;
foreach (InnerNode trans in nd._transitionsArr)
{
if (trans._char == c)
{
ndNew = trans; break;
}
}
if (ndNew == null)
{
ndNew = new InnerNode(nd, c);
nd.AddTransition(ndNew);
}
nd = ndNew;
}
nd.AddResult(p, i);
}
// Find failure functions
var nodes = new List <InnerNode>();
// level 1 nodes - fail to root node
foreach (InnerNode nd in _root._transitionsArr)
{
nd._failure = _root;
foreach (InnerNode trans in nd._transitionsArr)
{
nodes.Add(trans);
}
}
// other nodes - using BFS
while (nodes.Count != 0)
{
var newNodes = new List <InnerNode>();
foreach (InnerNode nd in nodes)
{
InnerNode r = nd._parent._failure;
char c = nd._char;
while (r != null && !r.ContainsTransition(c))
{
r = r._failure;
}
if (r == null)
{
nd._failure = _root;
}
else
{
nd._failure = r.GetTransition(c);
foreach (var result in nd._failure._results)
{
nd.AddResult(result.Key, result.Value);
}
}
// add child nodes to BFS list
foreach (InnerNode child in nd._transitionsArr)
{
newNodes.Add(child);
}
}
nodes = newNodes;
}
_root._failure = _root;
}
