Antlr4.Runtime.Tree.Pattern.ParseTreePatternMatcher.Split C# (CSharp) Method

        internal virtual IList<Chunk> Split(string pattern)
        {
            int p = 0;
            int n = pattern.Length;
            IList<Chunk> chunks = new List<Chunk>();
            // find all start and stop indexes first, then collect
            IList<int> starts = new List<int>();
            IList<int> stops = new List<int>();
            while (p < n)
            {
                if (p == pattern.IndexOf(escape + start, p))
                {
                    p += escape.Length + start.Length;
                }
                else
                {
                    if (p == pattern.IndexOf(escape + stop, p))
                    {
                        p += escape.Length + stop.Length;
                    }
                    else
                    {
                        if (p == pattern.IndexOf(start, p))
                        {
                            starts.Add(p);
                            p += start.Length;
                        }
                        else
                        {
                            if (p == pattern.IndexOf(stop, p))
                            {
                                stops.Add(p);
                                p += stop.Length;
                            }
                            else
                            {
                                p++;
                            }
                        }
                    }
                }
            }
            //		System.out.println("");
            //		System.out.println(starts);
            //		System.out.println(stops);
            if (starts.Count > stops.Count)
            {
                throw new ArgumentException("unterminated tag in pattern: " + pattern);
            }
            if (starts.Count < stops.Count)
            {
                throw new ArgumentException("missing start tag in pattern: " + pattern);
            }
            int ntags = starts.Count;
            for (int i = 0; i < ntags; i++)
            {
                if (starts[i] >= stops[i])
                {
                    throw new ArgumentException("tag delimiters out of order in pattern: " + pattern);
                }
            }
            // collect into chunks now
            if (ntags == 0)
            {
                string text = Sharpen.Runtime.Substring(pattern, 0, n);
                chunks.Add(new TextChunk(text));
            }
            if (ntags > 0 && starts[0] > 0)
            {
                // copy text up to first tag into chunks
                string text = Sharpen.Runtime.Substring(pattern, 0, starts[0]);
                chunks.Add(new TextChunk(text));
            }
            for (int i_1 = 0; i_1 < ntags; i_1++)
            {
                // copy inside of <tag>
                string tag = Sharpen.Runtime.Substring(pattern, starts[i_1] + start.Length, stops[i_1]);
                string ruleOrToken = tag;
                string label = null;
                int colon = tag.IndexOf(':');
                if (colon >= 0)
                {
                    label = Sharpen.Runtime.Substring(tag, 0, colon);
                    ruleOrToken = Sharpen.Runtime.Substring(tag, colon + 1, tag.Length);
                }
                chunks.Add(new TagChunk(label, ruleOrToken));
                if (i_1 + 1 < ntags)
                {
                    // copy from end of <tag> to start of next
                    string text = Sharpen.Runtime.Substring(pattern, stops[i_1] + stop.Length, starts[i_1 + 1]);
                    chunks.Add(new TextChunk(text));
                }
            }
            if (ntags > 0)
            {
                int afterLastTag = stops[ntags - 1] + stop.Length;
                if (afterLastTag < n)
                {
                    // copy text from end of last tag to end
                    string text = Sharpen.Runtime.Substring(pattern, afterLastTag, n);
                    chunks.Add(new TextChunk(text));
                }
            }
            // strip out the escape sequences from text chunks but not tags
            for (int i_2 = 0; i_2 < chunks.Count; i_2++)
            {
                Chunk c = chunks[i_2];
                if (c is TextChunk)
                {
                    TextChunk tc = (TextChunk)c;
                    string unescaped = tc.Text.Replace(escape, string.Empty);
                    if (unescaped.Length < tc.Text.Length)
                    {
                        chunks.Set(i_2, new TextChunk(unescaped));
                    }
                }
            }
            return chunks;
        }