Paddings.java

/*
 * Copyright (c) 2014, 2014, 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.jmh.generators.core;

import java.io.PrintWriter;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.StringJoiner;

public class Paddings {

    // This class is responsible for padding in generated code.
    // If padding needs to be adjusted, also change the manual paddings
    // in infra classes like Blackhole and various *Params.

    private static final Map<String, String> PADDING_CACHE =
            Collections.synchronizedMap(new HashMap<>());

    private static String generate(String prefix) {
        if (prefix.isEmpty()) {
            throw new IllegalArgumentException("prefix must not be empty");
        }
        StringJoiner sj = new StringJoiner("");
        sj.add("    byte ");
        for (int q = 0; q < 16; q++) {
            if (q != 0) {
                sj.add(", ");
            }
            sj.add(prefix);
            sj.add(String.format("%02x", q));
        }
        sj.add(";");
        sj.add(System.lineSeparator());

        // 32 longs * 8 bytes = 256 bytes
        for (int q = 0; q < 32; q++) {
            if (q % 16 == 0) {
                if (q > 0) {
                    sj.add(";");
                    sj.add(System.lineSeparator());
                }
                sj.add("    long ");
            } else {
                sj.add(", ");
            }
            sj.add(prefix);
            sj.add(String.format("%02x", 16 + q));
        }
        sj.add(";");
        sj.add(System.lineSeparator());

        return sj.toString();
    }

    public static void padding(PrintWriter writer, String prefix) {
        writer.print(PADDING_CACHE.computeIfAbsent(prefix, Paddings::generate));
    }
}