code: private static int getLink(char ch) {
          if (ch >= '\u0622' && ch <= '\u06D3') {
              return araLink[ch - '\u0622'];
          } else if (ch == '\u200D') {
              return 3;
          } else if (ch >= '\u206D' && ch <= '\u206F') {
              return 4;
          } else if (ch >= '\uFE70' && ch <= '\uFEFC') {
              return presLink[ch - '\uFE70'];
          } else {
              return 0;
          }
      }
docs: /*
  Name    : getLink
  Function: Resolves the link between the characters as
  Arabic characters have four forms :
  Isolated, Initial, Middle and Final Form