/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
* <p>
* Copyright (c) 2006 John Reilly (www.inconspicuous.org) This work is a
* translation from C to Java of jsmin.c published by Douglas Crockford.
* Permission is hereby granted to use the Java version under the same
* conditions as the jsmin.c on which it is based.
* <p>
* http://www.crockford.com/javascript/jsmin.html
*/
package org.apache.felix.configurator.impl.json;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.io.Writer;
public class JSMin {
private static final int EOF = -1;
private final PushbackReader in;
private final Writer out;
private int theA;
private int theB;
private int theLookahead = EOF;
private int theX = EOF;
private int theY = EOF;
public JSMin(final Reader in, final 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.
*/
private boolean isAlphanum(final 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.
*/
private int get() throws IOException {
int c = theLookahead;
theLookahead = EOF;
if ( c == EOF ) {
c = in.read();
}
if (c >= ' ' || c == '\n' || c == EOF) {
return c;
}
if (c == '\r') {
return '\n';
}
return ' ';
}
/**
* peek -- get the next character without getting it.
*/
private int peek() throws IOException {
theLookahead = get();
return theLookahead;
}
/**
* next -- get the next character, excluding comments. peek() is used to see
* if a '/' is followed by a '/' or '*'.
*/
private int next() throws IOException {
int c = get();
if (c == '/') {
switch (peek()) {
case '/':
for (;;) {
c = get();
if (c <= '\n') {
break;
}
}
break;
case '*':
get();
while (c != ' ') {
switch (get()) {
case '*':
if (peek() == '/') {
get();
c = ' ';
}
break;
case EOF:
throw new IOException("Unterminated comment.");
}
}
break;
}
}
theY = theX;
theX = c;
return c;
}
/**
* action -- do something! What you do is determined by the argument:
* <ul>
* <li>1 Output A. Copy B to A. Get the next B.</li>
* <li>2 Copy B to A. Get the next B. (Delete A).</li>
* <li>3 Get the next B. (Delete B).</li>
* </ul>
* action treats a string as a single character. Wow!<br/>
* action recognizes a regular expression if it is preceded by ( or , or =.
*/
void action(final int d) throws IOException {
switch (d) {
case 1:
out.write(theA);
if ((theY == '\n' || theY == ' ') &&
(theA == '+' || theA == '-' || theA == '*' || theA == '/') &&
(theB == '+' || theB == '-' || theB == '*' || theB == '/')) {
out.write(theY);
}
case 2:
theA = theB;
if (theA == '\'' || theA == '"' || theA == '`') {
for (;;) {
out.write(theA);
theA = get();
if (theA == theB) {
break;
}
if (theA == '\\') {
out.write(theA);
theA = get();
}
if ( theA == EOF) {
throw new IOException("Unterminated string literal.");
}
}
}
case 3:
theB = next();
if (theB == '/'
&& (theA == '(' || theA == ',' || theA == '=' || theA == ':'
|| theA == '[' || theA == '!' || theA == '&' || theA == '|'
|| theA == '?' || theA == '+' || theA == '-' || theA == '~'
|| theA == '*' || theA == '/' || theA == '{' || theA == '\n')) {
out.write(theA);
if (theA == '/' || theA == '*') {
out.write(' ');
}
out.write(theB);
for (;;) {
theA = get();
if (theA == '[') {
for (;;) {
out.write(theA);
theA = get();
if (theA == ']') {
break;
}
if (theA == '\\') {
out.write(theA);
theA = get();
}
if (theA == EOF) {
throw new IOException("Unterminated set in Regular Expression literal.");
}
}
} else if (theA == '/') {
switch (peek()) {
case '/':
case '*':
throw new IOException("Unterminated set in Regular Expression literal.");
}
break;
} else if (theA == '\\') {
out.write(theA);
theA = get();
} else if (theA == EOF) {
throw new IOException("Unterminated Regular Expression literal.");
}
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 {
if (peek() == 0xEF) {
get();
get();
get();
}
theA = '\n';
action(3);
while (theA != EOF) {
switch (theA) {
case ' ':
action(isAlphanum(theB) ? 1: 2);
break;
case '\n':
switch (theB) {
case '{':
case '[':
case '(':
case '+':
case '-':
case '!':
case '~':
action(1);
break;
case ' ':
action(3);
break;
default:
action(isAlphanum(theB) ? 1: 2);
}
break;
default:
switch (theB) {
case ' ':
action(isAlphanum(theB) ? 1: 3);
break;
case '\n':
switch (theA) {
case '}':
case ']':
case ')':
case '+':
case '-':
case '"':
case '\'':
case '`':
action(1);
break;
default:
action(isAlphanum(theB) ? 1: 3);
}
break;
default:
action(1);
break;
}
}
}
out.flush();
}
}