System.Text.RegularExpressions.RegexCharClass.CharInCategoryGroup C# (CSharp) Method

        private static bool CharInCategoryGroup(char ch, UnicodeCategory chcategory, string category, ref int i) {
            i++;

            int curcat = (short) category[i];
            if (curcat > 0) {
                // positive case - the character must be in ANY of the categories in the group
                bool answer = false;

                while (curcat != 0) {
                    if (!answer) {
                        --curcat;
                        if (chcategory == (UnicodeCategory) curcat)
                            answer = true;
                    }
                    i++;
                    curcat = (short) category[i];
                }
                return answer;
            }
            else {

                // negative case - the character must be in NONE of the categories in the group
                bool answer = true;

                while (curcat != 0) {
                    if (answer) {
                        //curcat = -curcat;
                        //--curcat;
                        curcat = -1 - curcat;
                        if (chcategory == (UnicodeCategory) curcat)
                            answer = false;
                    }
                    i++;
                    curcat = (short) category[i];
                }
                return answer;
            }
        }