package util;

public class EscapeUnescape {

	public static String escape(String src) {

		int i;

		char j;

		StringBuffer tmp = new StringBuffer();

		tmp.ensureCapacity(src.length() * 6);

		for (i = 0; i < src.length(); i++) {

			j = src.charAt(i);

			if (Character.isDigit(j) || Character.isLowerCase(j)

					|| Character.isUpperCase(j))

				tmp.append(j);

			else if (j < 256) {

				tmp.append("%");

				if (j < 16)

					tmp.append("0");

				tmp.append(Integer.toString(j, 16));

			} else {

				tmp.append("%u");

				tmp.append(Integer.toString(j, 16));

			}

		}

		return tmp.toString();

	}

	public static String unescape(String src) {

		StringBuffer tmp = new StringBuffer();

		tmp.ensureCapacity(src.length());

		int lastPos = 0, pos = 0;

		char ch;

		while (lastPos < src.length()) {

			pos = src.indexOf("%", lastPos);

			if (pos == lastPos) {

				if (src.charAt(pos + 1) == 'u') {

					ch = (char) Integer.parseInt(src

							.substring(pos + 2, pos + 6), 16);

					tmp.append(ch);

					lastPos = pos + 6;

				} else {

					ch = (char) Integer.parseInt(src

							.substring(pos + 1, pos + 3), 16);

					tmp.append(ch);

					lastPos = pos + 3;

				}

			} else {

				if (pos == -1) {

					tmp.append(src.substring(lastPos));

					lastPos = src.length();

				} else {

					tmp.append(src.substring(lastPos, pos));

					lastPos = pos;

				}

			}

		}

		return tmp.toString();

	}

	public static void main(String[] args) {

		String tmp = "~!@#$%^&*()_+|\\=-,./?><;'][{}\"";

		System.out.println("testing escape : " + tmp);

		tmp = escape(tmp);

		System.out.println(tmp);

		System.out.println("testing unescape :" + tmp);

		System.out.println(unescape(tmp));

	}

}