/*
* Copyright (c) 1998-2010 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source 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 of the License, or
* (at your option) any later version.
*
* Resin Open Source 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, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
*
* Free Software Foundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Nam Nguyen
*/
package com.caucho.quercus.lib.gettext.expr;
/**
* Parses a gettext plural expression.
*/
class PluralExprParser {
final static int INTEGER = 256;
final static int EQ = 270;
final static int NEQ = 271;
final static int LE = 272;
final static int GE = 273;
final static int AND = 280;
final static int OR = 281;
final static int VARIABLE_N = 290;
final static int UNKNOWN = 291;
final static int UNSET = 292;
private CharSequence _expr;
private int _exprLength;
private int _parseIndex;
private Expr _npluralsExpr;
private Expr _pluralExpr;
private int _peekToken;
private int _integer;
private boolean _isError;
private boolean _isInitialized;
protected PluralExprParser(CharSequence expr) {
_expr = expr;
_exprLength = expr.length();
_isInitialized = false;
}
public Expr getNpluralsExpr() {
if (!_isInitialized) {
init();
}
if (_isError) {
return null;
}
return _npluralsExpr;
}
public Expr getPluralExpr() {
if (!_isInitialized) {
init();
}
if (_isError) {
return null;
}
return _pluralExpr;
}
private void init() {
_parseIndex = 0;
_peekToken = UNSET;
_isError = false;
parseAssignExpr();
parseAssignExpr();
_isInitialized = true;
}
private void parseAssignExpr() {
int ch = consumeWhiteSpace();
boolean isNplurals;
if (ch == 'n'
&& read() == 'p'
&& read() == 'l'
&& read() == 'u'
&& read() == 'r'
&& read() == 'a'
&& read() == 'l'
&& read() == 's') {
isNplurals = true;
} else if (ch == 'p'
&& read() == 'l'
&& read() == 'u'
&& read() == 'r'
&& read() == 'a'
&& read() == 'l') {
isNplurals = false;
} else {
return;
}
ch = consumeWhiteSpace();
if (ch != '=') {
return;
}
if (isNplurals) {
_npluralsExpr = parseIfExpr();
} else {
_pluralExpr = parseIfExpr();
}
// Read semicolon
parseToken();
}
private Expr parseLiteralExpr() {
int token = parseToken();
if (token == INTEGER) {
return new LiteralExpr(_integer);
} else if (token == VARIABLE_N) {
return NExpr.N_EXPR;
} else {
return error("Expected INTEGER");
}
}
private Expr parseParenExpr() {
int token = parseToken();
if (token != '(') {
_peekToken = token;
return parseLiteralExpr();
}
Expr expr = parseIfExpr();
if (parseToken() != ')') {
return error("Expected ')'");
}
return expr;
}
private Expr parseMulExpr() {
Expr expr = parseParenExpr();
while (true) {
int token = parseToken();
switch (token) {
case '%':
expr = new ModExpr(expr, parseParenExpr());
break;
case '*':
expr = new MulExpr(expr, parseParenExpr());
break;
case '/':
expr = new DivExpr(expr, parseParenExpr());
break;
default:
_peekToken = token;
return expr;
}
}
}
private Expr parseAddExpr() {
Expr expr = parseMulExpr();
while (true) {
int token = parseToken();
switch (token) {
case '+':
expr = new AddExpr(expr, parseMulExpr());
break;
case '-':
expr = new SubExpr(expr, parseMulExpr());
break;
default:
_peekToken = token;
return expr;
}
}
}
private Expr parseCmpExpr() {
Expr expr = parseAddExpr();
while (true) {
int token = parseToken();
switch (token) {
case '>':
expr = new GTExpr(expr, parseAddExpr());
break;
case '<':
expr = new LTExpr(expr, parseAddExpr());
break;
case GE:
expr = new GEExpr(expr, parseAddExpr());
break;
case LE:
expr = new LEExpr(expr, parseAddExpr());
break;
case EQ:
expr = new EQExpr(expr, parseAddExpr());
break;
case NEQ:
expr = new NEQExpr(expr, parseAddExpr());
break;
default:
_peekToken = token;
return expr;
}
}
}
private Expr parseAndExpr() {
Expr expr = parseCmpExpr();
while (true) {
int token = parseToken();
if (token != AND) {
_peekToken = token;
return expr;
}
expr = new AndExpr(expr, parseCmpExpr());
}
}
private Expr parseOrExpr() {
Expr expr = parseAndExpr();
while (true) {
int token = parseToken();
if (token != OR) {
_peekToken = token;
return expr;
}
expr = new OrExpr(expr, parseAndExpr());
}
}
private Expr parseIfExpr() {
Expr expr = parseOrExpr();
int token = parseToken();
if (token != '?') {
_peekToken = token;
return expr;
}
Expr trueExpr = parseIfExpr();
token = parseToken();
if (token != ':') {
return error("Expected ':'");
}
Expr falseExpr = parseIfExpr();
return new IfExpr(expr, trueExpr, falseExpr);
}
private int parseToken() {
if (_peekToken != UNSET) {
int toReturn = _peekToken;
_peekToken = UNSET;
return toReturn;
}
int ch = consumeWhiteSpace();
switch (ch) {
case '(':
case ')':
case '?':
case ':':
case ';':
case '+':
case '-':
case '%':
case '*':
case '/':
return ch;
case '>':
if (read() == '=') {
return GE;
}
unread();
return '>';
case '<':
if (read() == '=') {
return LE;
}
unread();
return '<';
case '=':
if (read() == '=') {
return EQ;
}
return UNKNOWN;
case '!':
if (read() == '=') {
return NEQ;
}
return UNKNOWN;
case '&':
if (read() == '&') {
return AND;
}
return UNKNOWN;
case '|':
if (read() == '|') {
return OR;
}
return UNKNOWN;
}
return parseIntegerToken(ch);
}
private int parseIntegerToken(int ch) {
if ('0' <= ch && ch <= '9') {
_integer = ch - '0';
for (ch = read(); '0' <= ch && ch <= '9'; ch = read()) {
_integer = _integer * 10 + ch - '0';
}
unread();
return INTEGER;
} else if (ch == 'n') {
if (Character.isLetter(read())) {
return UNKNOWN;
}
unread();
return VARIABLE_N;
}
return UNKNOWN;
}
/**
* Consumes whitespaces and returns the last non-whitespace character.
*/
private int consumeWhiteSpace() {
while (true) {
int ch = read();
switch (ch) {
case ' ':
case '\n':
case '\t':
case '\r':
continue;
default:
return ch;
}
}
}
private int read() {
if (_parseIndex < _exprLength) {
return _expr.charAt(_parseIndex++);
} else {
return -1;
}
}
private void unread() {
if (_parseIndex > 0 && _parseIndex < _exprLength) {
_parseIndex--;
}
}
private Expr error(String message) {
_isError = true;
return NExpr.N_EXPR;
}
}