/*

 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package org.openjdk.tests.shapegen;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.io.IOException;

import java.io.StringReader;

import static java.lang.Character.isLetter;

import static java.lang.Character.isUpperCase;

import static java.lang.Character.isWhitespace;

/**

 * Parse a type template definition string

 *

 *   input     :: classDef

 *   classDef  :: letter [ ( classDef* ) ]

 *

 * @author Robert Field

 */

public class TTParser extends StringReader {

    private Map<Character, TTNode> letterMap = new HashMap<>();

    private char ch;

    private final String def;

    public TTParser(String s) {

        super(s);

        this.def = s;

    }

    private void advance() throws IOException {

        do {

            ch = (char)read();

        } while (isWhitespace(ch));

    }

    public TTNode parse() {

        try {

            advance();

            return classDef();

        } catch (IOException t) {

            throw new RuntimeException(t);

        }

    }

    private TTNode classDef() throws IOException {

        if (!isLetter(ch)) {

            if (ch == (char)-1) {

                throw new IOException("Unexpected end of type template in " + def);

            } else {

                throw new IOException("Unexpected character in type template: " + (Character)ch + " in " + def);

            }

        }

        char nodeCh = ch;

        TTNode node = letterMap.get(nodeCh);

        boolean canBeClass = isUpperCase(nodeCh);

        advance();

        if (node == null) {

            List<TTNode> subtypes = new ArrayList<>();

            if (ch == '(') {

                advance();

                while (ch != ')') {

                    subtypes.add(classDef());

                }

                advance();

            }

            node = new TTNode(subtypes, canBeClass);

            letterMap.put(nodeCh, node);

        }

        return node;

    }

}