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 * Copyright (c) 2020, 2020, Red Hat Inc. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * 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.
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package com.oracle.objectfile.debugentry;

import java.util.HashMap;
import java.util.Iterator;

Allows incoming strings to be reduced to unique (up to equals) instances and supports marking of
strings which need to be written to the debug_str section and retrieval of the location offset
after writing.
/**
 * Allows incoming strings to be reduced to unique (up to equals) instances and supports marking of
 * strings which need to be written to the debug_str section and retrieval of the location offset
 * after writing.
 */
public class StringTable implements Iterable<StringEntry> {

    private final HashMap<String, StringEntry> table;

    public StringTable() {
        this.table = new HashMap<>();
    }

    
Ensures a unique instance of a string exists in the table, inserting the supplied String if
no equivalent String is already present. This should only be called before the string section
has been written.
Params:
string – the string to be included in the table
Returns:
the unique instance of the String/**
     * Ensures a unique instance of a string exists in the table, inserting the supplied String if
     * no equivalent String is already present. This should only be called before the string section
     * has been written.
     *
     * @param string the string to be included in the table
     * @return the unique instance of the String
     */
    public String uniqueString(String string) {
        return ensureString(string, false);
    }

    
Ensures a unique instance of a string exists in the table and is marked for inclusion in the
debug_str section, inserting the supplied String if no equivalent String is already present.
This should only be called before the string section has been written.
Params:
string – the string to be included in the table and marked for inclusion in the
           debug_str section
Returns:
the unique instance of the String/**
     * Ensures a unique instance of a string exists in the table and is marked for inclusion in the
     * debug_str section, inserting the supplied String if no equivalent String is already present.
     * This should only be called before the string section has been written.
     *
     * @param string the string to be included in the table and marked for inclusion in the
     *            debug_str section
     * @return the unique instance of the String
     */
    public String uniqueDebugString(String string) {
        return ensureString(string, true);
    }

    private String ensureString(String string, boolean addToStrSection) {
        StringEntry stringEntry = table.get(string);
        if (stringEntry == null) {
            stringEntry = new StringEntry(string);
            table.put(string, stringEntry);
        }
        if (addToStrSection && !stringEntry.isAddToStrSection()) {
            stringEntry.setAddToStrSection();
        }
        return stringEntry.getString();
    }

    
Retrieves the offset at which a given string was written into the debug_str section. This
should only be called after the string section has been written.
Params:
string – the strng whose offset is to be retrieved
Returns:
the offset or -1 if the string does not define an entry or the entry has not been
        written to the debug_str section/**
     * Retrieves the offset at which a given string was written into the debug_str section. This
     * should only be called after the string section has been written.
     *
     * @param string the strng whose offset is to be retrieved
     * @return the offset or -1 if the string does not define an entry or the entry has not been
     *         written to the debug_str section
     */
    public int debugStringIndex(String string) {
        StringEntry stringEntry = table.get(string);
        assert stringEntry != null : "\"" + string + "\" not in string table";
        if (stringEntry == null) {
            return -1;
        }
        return stringEntry.getOffset();
    }

    @Override
    public Iterator<StringEntry> iterator() {
        return table.values().iterator();
    }
}