/*

 * Copyright (c) 2012, 2013, 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 java.lang.invoke;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.internal.org.objectweb.asm.Opcodes;

import jdk.internal.org.objectweb.asm.Type;

import sun.invoke.util.BytecodeDescriptor;

import sun.invoke.util.Wrapper;

import static sun.invoke.util.Wrapper.*;

class TypeConvertingMethodAdapter extends MethodVisitor {

    TypeConvertingMethodAdapter(MethodVisitor mv) {

        super(Opcodes.ASM5, mv);

    }

    private static final int NUM_WRAPPERS = Wrapper.values().length;

    private static final String NAME_OBJECT = "java/lang/Object";

    private static final String WRAPPER_PREFIX = "Ljava/lang/";

    // Same for all primitives; name of the boxing method

    private static final String NAME_BOX_METHOD = "valueOf";

    // Table of opcodes for widening primitive conversions; NOP = no conversion

    private static final int[][] wideningOpcodes = new int[NUM_WRAPPERS][NUM_WRAPPERS];

    private static final Wrapper[] FROM_WRAPPER_NAME = new Wrapper[16];

    // Table of wrappers for primitives, indexed by ASM type sorts

    private static final Wrapper[] FROM_TYPE_SORT = new Wrapper[16];

    static {

        for (Wrapper w : Wrapper.values()) {

            if (w.basicTypeChar() != 'L') {

                int wi = hashWrapperName(w.wrapperSimpleName());

                assert (FROM_WRAPPER_NAME[wi] == null);

                FROM_WRAPPER_NAME[wi] = w;

            }

        }

        for (int i = 0; i < NUM_WRAPPERS; i++) {

            for (int j = 0; j < NUM_WRAPPERS; j++) {

                wideningOpcodes[i][j] = Opcodes.NOP;

            }

        }

        initWidening(LONG,   Opcodes.I2L, BYTE, SHORT, INT, CHAR);

        initWidening(LONG,   Opcodes.F2L, FLOAT);

        initWidening(FLOAT,  Opcodes.I2F, BYTE, SHORT, INT, CHAR);

        initWidening(FLOAT,  Opcodes.L2F, LONG);

        initWidening(DOUBLE, Opcodes.I2D, BYTE, SHORT, INT, CHAR);

        initWidening(DOUBLE, Opcodes.F2D, FLOAT);

        initWidening(DOUBLE, Opcodes.L2D, LONG);

        FROM_TYPE_SORT[Type.BYTE] = Wrapper.BYTE;

        FROM_TYPE_SORT[Type.SHORT] = Wrapper.SHORT;

        FROM_TYPE_SORT[Type.INT] = Wrapper.INT;

        FROM_TYPE_SORT[Type.LONG] = Wrapper.LONG;

        FROM_TYPE_SORT[Type.CHAR] = Wrapper.CHAR;

        FROM_TYPE_SORT[Type.FLOAT] = Wrapper.FLOAT;

        FROM_TYPE_SORT[Type.DOUBLE] = Wrapper.DOUBLE;

        FROM_TYPE_SORT[Type.BOOLEAN] = Wrapper.BOOLEAN;

    }

    private static void initWidening(Wrapper to, int opcode, Wrapper... from) {

        for (Wrapper f : from) {

            wideningOpcodes[f.ordinal()][to.ordinal()] = opcode;

        }

    }

    /**

     * Class name to Wrapper hash, derived from Wrapper.hashWrap()

     * @param xn

     * @return The hash code 0-15

     */

    private static int hashWrapperName(String xn) {

        if (xn.length() < 3) {

            return 0;

        }

        return (3 * xn.charAt(1) + xn.charAt(2)) % 16;

    }

    private Wrapper wrapperOrNullFromDescriptor(String desc) {

        if (!desc.startsWith(WRAPPER_PREFIX)) {

            // Not a class type (array or method), so not a boxed type

            // or not in the right package

            return null;

        }

        // Pare it down to the simple class name

        String cname = desc.substring(WRAPPER_PREFIX.length(), desc.length() - 1);

        // Hash to a Wrapper

        Wrapper w = FROM_WRAPPER_NAME[hashWrapperName(cname)];

        if (w == null || w.wrapperSimpleName().equals(cname)) {

            return w;

        } else {

            return null;

        }

    }

    private static String wrapperName(Wrapper w) {

        return "java/lang/" + w.wrapperSimpleName();

    }

    private static String unboxMethod(Wrapper w) {

        return w.primitiveSimpleName() + "Value";

    }

    private static String boxingDescriptor(Wrapper w) {

        return String.format("(%s)L%s;", w.basicTypeChar(), wrapperName(w));

    }

    private static String unboxingDescriptor(Wrapper w) {

        return "()" + w.basicTypeChar();

    }

    void boxIfTypePrimitive(Type t) {

        Wrapper w = FROM_TYPE_SORT[t.getSort()];

        if (w != null) {

            box(w);

        }

    }

    void widen(Wrapper ws, Wrapper wt) {

        if (ws != wt) {

            int opcode = wideningOpcodes[ws.ordinal()][wt.ordinal()];

            if (opcode != Opcodes.NOP) {

                visitInsn(opcode);

            }

        }

    }

    void box(Wrapper w) {

        visitMethodInsn(Opcodes.INVOKESTATIC,

                wrapperName(w),

                NAME_BOX_METHOD,

                boxingDescriptor(w), false);

    }

    /**

     * Convert types by unboxing. The source type is known to be a primitive wrapper.

     * @param sname A primitive wrapper corresponding to wrapped reference source type

     * @param wt A primitive wrapper being converted to

     */

    void unbox(String sname, Wrapper wt) {

        visitMethodInsn(Opcodes.INVOKEVIRTUAL,

                sname,

                unboxMethod(wt),

                unboxingDescriptor(wt), false);

    }

    private String descriptorToName(String desc) {

        int last = desc.length() - 1;

        if (desc.charAt(0) == 'L' && desc.charAt(last) == ';') {

            // In descriptor form

            return desc.substring(1, last);

        } else {

            // Already in internal name form

            return desc;

        }

    }

    void cast(String ds, String dt) {

        String ns = descriptorToName(ds);

        String nt = descriptorToName(dt);

        if (!nt.equals(ns) && !nt.equals(NAME_OBJECT)) {

            visitTypeInsn(Opcodes.CHECKCAST, nt);

        }

    }

    private boolean isPrimitive(Wrapper w) {

        return w != OBJECT;

    }

    private Wrapper toWrapper(String desc) {

        char first = desc.charAt(0);

        if (first == '[' || first == '(') {

            first = 'L';

        }

        return Wrapper.forBasicType(first);

    }

    /**

     * Convert an argument of type 'arg' to be passed to 'target' assuring that it is 'functional'.

     * Insert the needed conversion instructions in the method code.

     * @param arg

     * @param target

     * @param functional

     */

    void convertType(Class<?> arg, Class<?> target, Class<?> functional) {

        if (arg.equals(target) && arg.equals(functional)) {

            return;

        }

        if (arg == Void.TYPE || target == Void.TYPE) {

            return;

        }

        if (arg.isPrimitive()) {

            Wrapper wArg = Wrapper.forPrimitiveType(arg);

            if (target.isPrimitive()) {

                // Both primitives: widening

                widen(wArg, Wrapper.forPrimitiveType(target));

            } else {

                // Primitive argument to reference target

                String dTarget = BytecodeDescriptor.unparse(target);

                Wrapper wPrimTarget = wrapperOrNullFromDescriptor(dTarget);

                if (wPrimTarget != null) {

                    // The target is a boxed primitive type, widen to get there before boxing

                    widen(wArg, wPrimTarget);

                    box(wPrimTarget);

                } else {

                    // Otherwise, box and cast

                    box(wArg);

                    cast(wrapperName(wArg), dTarget);

                }

            }

        } else {

            String dArg = BytecodeDescriptor.unparse(arg);

            String dSrc;

            if (functional.isPrimitive()) {

                dSrc = dArg;

            } else {

                // Cast to convert to possibly more specific type, and generate CCE for invalid arg

                dSrc = BytecodeDescriptor.unparse(functional);

                cast(dArg, dSrc);

            }

            String dTarget = BytecodeDescriptor.unparse(target);

            if (target.isPrimitive()) {

                Wrapper wTarget = toWrapper(dTarget);

                // Reference argument to primitive target

                Wrapper wps = wrapperOrNullFromDescriptor(dSrc);

                if (wps != null) {

                    if (wps.isSigned() || wps.isFloating()) {

                        // Boxed number to primitive

                        unbox(wrapperName(wps), wTarget);

                    } else {

                        // Character or Boolean

                        unbox(wrapperName(wps), wps);

                        widen(wps, wTarget);

                    }

                } else {

                    // Source type is reference type, but not boxed type,

                    // assume it is super type of target type

                    String intermediate;

                    if (wTarget.isSigned() || wTarget.isFloating()) {

                        // Boxed number to primitive

                        intermediate = "java/lang/Number";

                    } else {

                        // Character or Boolean

                        intermediate = wrapperName(wTarget);

                    }

                    cast(dSrc, intermediate);

                    unbox(intermediate, wTarget);

                }

            } else {

                // Both reference types: just case to target type

                cast(dSrc, dTarget);

            }

        }

    }

    /**

     * The following method is copied from

     * org.objectweb.asm.commons.InstructionAdapter. Part of ASM: a very small

     * and fast Java bytecode manipulation framework.

     * Copyright (c) 2000-2005 INRIA, France Telecom All rights reserved.

     */

    void iconst(final int cst) {

        if (cst >= -1 && cst <= 5) {

            mv.visitInsn(Opcodes.ICONST_0 + cst);

        } else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {

            mv.visitIntInsn(Opcodes.BIPUSH, cst);

        } else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {

            mv.visitIntInsn(Opcodes.SIPUSH, cst);

        } else {

            mv.visitLdcInsn(cst);

        }

    }

}