Java example source code file (Mangle.java)

This example Java source code file (Mangle.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

elements, fieldstub, java_, mangle, method_jdk_1, method_jni_long, method_jni_short, string, stringbuilder, typeelement, types, typesignature, variableelement

The Mangle.java Java example source code

/*
 * Copyright (c) 2002, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package com.sun.tools.javah;

import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.util.Elements;
import javax.lang.model.util.Types;

/**
 * A utility for mangling java identifiers into C names.  Should make
 * this more fine grained and distribute the functionality to the
 * generators.
 *
 * <p>This is NOT part of any supported API.
 * If you write code that depends on this, you do so at your own
 * risk.  This code and its internal interfaces are subject to change
 * or deletion without notice.</b>

 *
 * @author  Sucheta Dambalkar(Revised)
 */
public class Mangle {

    public static class Type {
        public static final int CLASS            = 1;
        public static final int FIELDSTUB        = 2;
        public static final int FIELD            = 3;
        public static final int JNI              = 4;
        public static final int SIGNATURE        = 5;
        public static final int METHOD_JDK_1     = 6;
        public static final int METHOD_JNI_SHORT = 7;
        public static final int METHOD_JNI_LONG  = 8;
    };

    private Elements elems;
    private Types types;

    Mangle(Elements elems, Types types) {
        this.elems = elems;
        this.types = types;
    }

    public final String mangle(CharSequence name, int mtype) {
        StringBuilder result = new StringBuilder(100);
        int length = name.length();

        for (int i = 0; i < length; i++) {
            char ch = name.charAt(i);
            if (isalnum(ch)) {
                result.append(ch);
            } else if ((ch == '.') &&
                       mtype == Mangle.Type.CLASS) {
                result.append('_');
            } else if (( ch == '$') &&
                       mtype == Mangle.Type.CLASS) {
                result.append('_');
                result.append('_');
            } else if (ch == '_' && mtype == Mangle.Type.FIELDSTUB) {
                result.append('_');
            } else if (ch == '_' && mtype == Mangle.Type.CLASS) {
                result.append('_');
            } else if (mtype == Mangle.Type.JNI) {
                String esc = null;
                if (ch == '_')
                    esc = "_1";
                else if (ch == '.')
                    esc = "_";
                else if (ch == ';')
                    esc = "_2";
                else if (ch == '[')
                    esc = "_3";
                if (esc != null) {
                    result.append(esc);
                } else {
                    result.append(mangleChar(ch));
                }
            } else if (mtype == Mangle.Type.SIGNATURE) {
                if (isprint(ch)) {
                    result.append(ch);
                } else {
                    result.append(mangleChar(ch));
                }
            } else {
                result.append(mangleChar(ch));
            }
        }

        return result.toString();
    }

    public String mangleMethod(ExecutableElement method, TypeElement clazz,
                                      int mtype) throws TypeSignature.SignatureException {
        StringBuilder result = new StringBuilder(100);
        result.append("Java_");

        if (mtype == Mangle.Type.METHOD_JDK_1) {
            result.append(mangle(clazz.getQualifiedName(), Mangle.Type.CLASS));
            result.append('_');
            result.append(mangle(method.getSimpleName(),
                                 Mangle.Type.FIELD));
            result.append("_stub");
            return result.toString();
        }

        /* JNI */
        result.append(mangle(getInnerQualifiedName(clazz), Mangle.Type.JNI));
        result.append('_');
        result.append(mangle(method.getSimpleName(),
                             Mangle.Type.JNI));
        if (mtype == Mangle.Type.METHOD_JNI_LONG) {
            result.append("__");
            String typesig = signature(method);
            TypeSignature newTypeSig = new TypeSignature(elems);
            String sig = newTypeSig.getTypeSignature(typesig,  method.getReturnType());
            sig = sig.substring(1);
            sig = sig.substring(0, sig.lastIndexOf(')'));
            sig = sig.replace('/', '.');
            result.append(mangle(sig, Mangle.Type.JNI));
        }

        return result.toString();
    }
    //where
        private String getInnerQualifiedName(TypeElement clazz) {
            return elems.getBinaryName(clazz).toString();
        }

    public final String mangleChar(char ch) {
        String s = Integer.toHexString(ch);
        int nzeros = 5 - s.length();
        char[] result = new char[6];
        result[0] = '_';
        for (int i = 1; i <= nzeros; i++)
            result[i] = '0';
        for (int i = nzeros+1, j = 0; i < 6; i++, j++)
            result[i] = s.charAt(j);
        return new String(result);
    }

    // Warning: duplicated in Gen
    private String signature(ExecutableElement e) {
        StringBuilder sb = new StringBuilder();
        String sep = "(";
        for (VariableElement p: e.getParameters()) {
            sb.append(sep);
            sb.append(types.erasure(p.asType()).toString());
            sep = ",";
        }
        sb.append(")");
        return sb.toString();
    }

    /* Warning: Intentional ASCII operation. */
    private static final boolean isalnum(char ch) {
        return ch <= 0x7f && /* quick test */
            ((ch >= 'A' && ch <= 'Z') ||
             (ch >= 'a' && ch <= 'z') ||
             (ch >= '0' && ch <= '9'));
    }

    /* Warning: Intentional ASCII operation. */
    private static final boolean isprint(char ch) {
        return ch >= 32 && ch <= 126;
    }
}