/*

  * 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

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  */

 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));

     }

     /**

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

      * @param ws 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));

     }

     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);

         }

     }

 }