/**
* Copyright (C) 2009 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.web.application.javascript;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.PushbackReader;
import java.io.Reader;
import java.io.Writer;
public class JSMin {
private static final int EOF = -1;
private PushbackReader in;
private Writer out;
private int theA;
private int theB;
public JSMin(Reader in, Writer out) {
this.in = new PushbackReader(in);
this.out = out;
}
/**
* isAlphanum -- return true if the character is a letter, digit, underscore, dollar sign, or non-ASCII character.
*/
static boolean isAlphanum(int c) {
return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || c == '_' || c == '$' || c == '\\' || c > 126);
}
/**
* get -- return the next character from stdin. Watch out for lookahead. If the character is a control character, translate
* it to a space or linefeed.
*/
int get() throws IOException {
int c = in.read();
if (c >= ' ' || c == '\n' || c == EOF) {
return c;
}
if (c == '\r') {
return '\n';
}
return ' ';
}
/**
* Get the next character without getting it.
*/
int peek() throws IOException {
int lookaheadChar = in.read();
in.unread(lookaheadChar);
return lookaheadChar;
}
/**
* next -- get the next character, excluding comments. peek() is used to see if a '/' is followed by a '/' or '*'.
*/
int next() throws IOException, UnterminatedCommentException {
int c = get();
if (c == '/') {
switch (peek()) {
case '/':
for (;;) {
c = get();
if (c <= '\n') {
return c;
}
}
case '*':
get();
for (;;) {
switch (get()) {
case '*':
if (peek() == '/') {
get();
return ' ';
}
break;
case EOF:
throw new UnterminatedCommentException();
}
}
default:
return c;
}
}
return c;
}
/**
* action -- do something! What you do is determined by the argument: <br/>
* 1. Output A. Copy B to A. Get the next B. <br/>
* 2. Copy B to A. Get the next B. (Delete A). <br/>
* 3. Get the next B. (Delete B). action treats a string as a single character. <br/>
* Wow! action recognizes a regular expression if it is preceded by ( or , or =.
*/
void action(int d) throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException,
UnterminatedStringLiteralException {
switch (d) {
case 1:
out.write(theA);
case 2:
theA = theB;
if (theA == '\'' || theA == '"') {
for (;;) {
out.write(theA);
theA = get();
if (theA == theB) {
break;
}
if (theA <= '\n') {
throw new UnterminatedStringLiteralException();
}
if (theA == '\\') {
out.write(theA);
theA = get();
}
}
}
case 3:
theB = next();
if (theB == '/'
&& (theA == '(' || theA == ',' || theA == '=' || theA == ':' || theA == '[' || theA == '!'
|| theA == '&' || theA == '|' || theA == '?' || theA == '{' || theA == '}' || theA == ';' || theA == '\n')) {
out.write(theA);
out.write(theB);
for (;;) {
theA = get();
if (theA == '/') {
break;
} else if (theA == '\\') {
out.write(theA);
theA = get();
} else if (theA <= '\n') {
throw new UnterminatedRegExpLiteralException();
}
out.write(theA);
}
theB = next();
}
}
}
/**
* jsmin -- Copy the input to the output, deleting the characters which are insignificant to JavaScript. Comments will be
* removed. Tabs will be replaced with spaces. Carriage returns will be replaced with linefeeds. Most spaces and linefeeds
* will be removed.
*/
public void jsmin() throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException,
UnterminatedStringLiteralException {
theA = '\n';
action(3);
while (theA != EOF) {
switch (theA) {
case ' ':
if (isAlphanum(theB)) {
action(1);
} else {
action(2);
}
break;
case '\n':
switch (theB) {
case '{':
case '[':
case '(':
case '+':
case '-':
action(1);
break;
case ' ':
action(3);
break;
default:
if (isAlphanum(theB)) {
action(1);
} else {
action(2);
}
}
break;
default:
switch (theB) {
case ' ':
if (isAlphanum(theA)) {
action(1);
break;
}
action(3);
break;
case '\n':
switch (theA) {
case '}':
case ']':
case ')':
case '+':
case '-':
case '"':
case '\'':
action(1);
break;
default:
if (isAlphanum(theA)) {
action(1);
} else {
action(3);
}
}
break;
default:
action(1);
break;
}
}
}
out.flush();
}
class UnterminatedCommentException extends Exception {
}
class UnterminatedStringLiteralException extends Exception {
}
class UnterminatedRegExpLiteralException extends Exception {
}
public static void main(String[] arg) throws IOException, UnterminatedRegExpLiteralException, UnterminatedCommentException, UnterminatedStringLiteralException {
JSMin jsmin = new JSMin(new FileReader(arg[0]), new PrintWriter(System.out));
jsmin.jsmin();
}
}