cz.vutbr.fit.xhriba01.bc.lib.Utils.java Source code

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Here is the source code for cz.vutbr.fit.xhriba01.bc.lib.Utils.java

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/*******************************************************************************
 * Copyright (c) 2014 Jaromr Hibal.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Jaromr Hibal <jaromirhribal@gmail.com> - initial API and implementation
 *******************************************************************************/
package cz.vutbr.fit.xhriba01.bc.lib;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.IOUtils;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.objectweb.asm.Opcodes;

/**
 * Contains useful utility methods.
 */
public class Utils {

    public static int INVALID_LINE = -1;
    public static int INVALID_OFFSET = -1;

    public static byte[] inputStreamToBytes(InputStream stream) {

        try {

            return IOUtils.toByteArray(stream);

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }

    public static String inputStreamToString(InputStream stream) {

        try {

            return IOUtils.toString(stream);

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }

    /**
     * Returns the package from full class name.
     * The className is always in format with slash as exists in .class files.
     * <b>Example:</b>
     * className: <code>java/util/ArrayList</code>
     * returns: <code>java.util</code>
     * 
     * @param className FQNT (for instance java/util/ArrayList)
     * @return the package from className (java.util from className example)
     */
    public static String getPackageFromClassName(String className) {
        IPath path = new Path(className);
        return convertClassPackageToJavaPackage(path.removeLastSegments(1).removeTrailingSeparator().toString());
    }

    /**
     * Converts package format used in .class files to package
     * format used in .java files (s/\//\./g).
     * <b>Example:</b>
     * classPackage: <code>java/util</code>
     * returns: <code>java.util</code>
     * 
     * @param path .class package format
     * @return package
     */
    public static String convertClassPackageToJavaPackage(String classPackage) {
        return classPackage.replace('/', '.');
    }

    /**
     * Returns the name of .class file from the .class file 
     * formatted class name.
     * <b>Example:</b>
     * className: <code>java/util/ArrayList</code>
     * returns: <code>ArrayList.class</code>
     * 
     * @param className .class formated class name (java/util/ArrayList)
     * @return .class file name 
     */
    public static String getClassFileFromClassName(String className) {
        IPath path = new Path(className);
        path = path.addFileExtension("class");
        return path.lastSegment();
    }

    /**
     * Creates text representation of asm method access flag.
     * 
     * @param flag asm method access flag
     * @return formatted string representing the access flag
     */
    public static String formatMethodAccessFlags(int flag) {
        List<String> accesses = new ArrayList<>();
        if ((flag & Opcodes.ACC_PUBLIC) != 0) {
            accesses.add("public");
        }
        if ((flag & Opcodes.ACC_PROTECTED) != 0) {
            accesses.add("protected");
        }
        if ((flag & Opcodes.ACC_PRIVATE) != 0) {
            accesses.add("private");
        }
        if ((flag & Opcodes.ACC_STATIC) != 0) {
            accesses.add("static");
        }
        if ((flag & Opcodes.ACC_ABSTRACT) != 0) {
            accesses.add("abstract");
        }
        if ((flag & Opcodes.ACC_FINAL) != 0) {
            accesses.add("final");
        }
        return join(accesses.toArray(new String[accesses.size()]), " ");
    }

    /**
     * Creates text representation of asm class access flag.
     * 
     * @param flag asm class access flag
     * @return formatted string representing the access flag
     */
    public static String formatClassAccessFlags(int flag) {
        List<String> accesses = new ArrayList<>();
        if ((flag & Opcodes.ACC_PUBLIC) != 0) {
            accesses.add("public");
        }
        if ((flag & Opcodes.ACC_PROTECTED) != 0) {
            accesses.add("protected");
        }
        if ((flag & Opcodes.ACC_PRIVATE) != 0) {
            accesses.add("private");
        }
        if ((flag & Opcodes.ACC_STATIC) != 0) {
            accesses.add("static");
        }
        if ((flag & Opcodes.ACC_ABSTRACT) != 0) {
            accesses.add("abstract");
        }
        if ((flag & Opcodes.ACC_FINAL) != 0) {
            accesses.add("final");
        }
        if ((flag & Opcodes.ACC_ENUM) != 0) {
            accesses.add("enum");
        } else if ((flag & Opcodes.ACC_INTERFACE) != 0) {
            accesses.add("interface");
        } else {
            accesses.add("class");
        }
        return join(accesses.toArray(new String[accesses.size()]), " ");
    }

    public static String join(String[] elements, String separator) {
        return join(elements, separator, 0);
    }

    /**
     * Join strings with separator.
     * <b>Example:</b>
     * elements: <code>java, util, ArrayList</code>
     * separator: <code>.</code>
     * returns: <code>java.util.ArrayList</code>
     * 
     * @param elements elements to join
     * @param separator placed between subsequent elements
     * @return joined string elements
     */
    public static String join(String[] elements, String separator, int startIndex) {

        StringBuilder sb = new StringBuilder();

        int len = elements.length;

        if (len - startIndex <= 0)
            return "";

        int cond = len - 1;

        for (int i = startIndex; i < cond; i++) {
            sb.append(elements[i]);
            sb.append(separator);
        }

        sb.append(elements[cond]);

        return sb.toString();
    }

}