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/*
* Copyright (c) 1998-2012 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;
}
}