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/**
* Copyright (C) 2023 BonitaSoft S.A.
* BonitaSoft, 32 rue Gustave Eiffel - 38000 Grenoble
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2.0 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* http://www.crockford.com/javascript/jsmin.html
*/
@SuppressWarnings("serial")
public class JSMin {
private static final int EOF = -1;
private final PushbackInputStream in;
private final OutputStream out;
private int theA;
private int theB;
private int theX = EOF;
private int theY = EOF;
public JSMin(final InputStream in, final OutputStream out) {
this.in = new PushbackInputStream(in);
this.out = out;
}
/**
* isAlphanum -- return true if the character is a letter, digit, underscore,
* dollar sign, or non-ASCII character.
*/
static 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.
*/
int get() throws IOException {
final 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 {
final 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') {
break;
}
}
break;
case '*':
get();
while (c != ' ') {
switch (get()) {
case '*':
if (peek() == '/') {
get();
c = ' ';
}
break;
case EOF:
throw new UnterminatedCommentException();
}
}
break;
}
}
theY = theX;
theX = c;
return c;
}
/**
* action -- do something! What you do is determined by the argument:
*
* - 1 Output A. Copy B to A. Get the next B.
* - 2 Copy B to A. Get the next B. (Delete A).
* - 3 Get the next B. (Delete B).
*
* action treats a string as a single character. Wow!
* action recognizes a regular expression if it is preceded by ( or , or =.
*/
void action(final int d) throws IOException,
UnterminatedRegExpLiteralException, UnterminatedCommentException,
UnterminatedStringLiteralException {
switch (d) {
case 1:
out.write(theA);
if (theA == theB && (theA == '+' || theA == '-') && theY != theA) {
out.write(' ');
}
case 2:
theA = theB;
if (theA == '\'' || 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 == '*' || 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 <= '\n') {
throw new UnterminatedRegExpLiteralException();
}
}
} else if (theA == '/') {
switch (peek()) {
case '/':
case '*':
throw new UnterminatedRegExpLiteralException();
}
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 {
if (peek() == 0xEF) {
get();
get();
get();
}
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 '-':
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 '\'':
case '`':
action(1);
break;
default:
if (isAlphanum(theA)) {
action(1);
} else {
action(3);
}
}
break;
default:
action(1);
break;
}
}
}
out.flush();
}
public static class UnterminatedCommentException extends Exception {
}
public static class UnterminatedStringLiteralException extends Exception {
}
public static class UnterminatedRegExpLiteralException extends Exception {
}
}