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      1 /*
      2  * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
      3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      4  *
      5  * This code is free software; you can redistribute it and/or modify it
      6  * under the terms of the GNU General Public License version 2 only, as
      7  * published by the Free Software Foundation.  Oracle designates this
      8  * particular file as subject to the "Classpath" exception as provided
      9  * by Oracle in the LICENSE file that accompanied this code.
     10  *
     11  * This code is distributed in the hope that it will be useful, but WITHOUT
     12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     14  * version 2 for more details (a copy is included in the LICENSE file that
     15  * accompanied this code).
     16  *
     17  * You should have received a copy of the GNU General Public License version
     18  * 2 along with this work; if not, write to the Free Software Foundation,
     19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     20  *
     21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     22  * or visit www.oracle.com if you need additional information or have any
     23  * questions.
     24  */
     25 
     26 package sun.invoke.util;
     27 
     28 public enum Wrapper {
     29     //        wrapperType    primitiveType  char            zero         emptyArray          format
     30     BOOLEAN(  Boolean.class, boolean.class, 'Z',      (Boolean)false, new boolean[0], Format.unsigned( 1)),
     31     // These must be in the order defined for widening primitive conversions in JLS 5.1.2
     32     BYTE   (     Byte.class,    byte.class, 'B',       (Byte)(byte)0, new    byte[0], Format.signed(   8)),
     33     SHORT  (    Short.class,   short.class, 'S',     (Short)(short)0, new   short[0], Format.signed(  16)),
     34     CHAR   (Character.class,    char.class, 'C',  (Character)(char)0, new    char[0], Format.unsigned(16)),
     35     INT    (  Integer.class,     int.class, 'I', (Integer)/*(int)*/0, new     int[0], Format.signed(  32)),
     36     LONG   (     Long.class,    long.class, 'J',       (Long)(long)0, new    long[0], Format.signed(  64)),
     37     FLOAT  (    Float.class,   float.class, 'F',     (Float)(float)0, new   float[0], Format.floating(32)),
     38     DOUBLE (   Double.class,  double.class, 'D',   (Double)(double)0, new  double[0], Format.floating(64)),
     39     OBJECT (   Object.class,  Object.class, 'L',                null, new  Object[0], Format.other(    1)),
     40     // VOID must be the last type, since it is "assignable" from any other type:
     41     VOID   (     Void.class,    void.class, 'V',                null,           null, Format.other(    0)),
     42     ;
     43 
     44     private final Class<?> wrapperType;
     45     private final Class<?> primitiveType;
     46     private final char     basicTypeChar;
     47     private final Object   zero;
     48     private final Object   emptyArray;
     49     private final int      format;
     50     private final String   wrapperSimpleName;
     51     private final String   primitiveSimpleName;
     52 
     53     private Wrapper(Class<?> wtype, Class<?> ptype, char tchar, Object zero, Object emptyArray, int format) {
     54         this.wrapperType = wtype;
     55         this.primitiveType = ptype;
     56         this.basicTypeChar = tchar;
     57         this.zero = zero;
     58         this.emptyArray = emptyArray;
     59         this.format = format;
     60         this.wrapperSimpleName = wtype.getSimpleName();
     61         this.primitiveSimpleName = ptype.getSimpleName();
     62     }
     63 
     64     /** For debugging, give the details of this wrapper. */
     65     public String detailString() {
     66         return wrapperSimpleName+
     67                 java.util.Arrays.asList(wrapperType, primitiveType,
     68                 basicTypeChar, zero,
     69                 "0x"+Integer.toHexString(format));
     70     }
     71 
     72     private static abstract class Format {
     73         static final int SLOT_SHIFT = 0, SIZE_SHIFT = 2, KIND_SHIFT = 12;
     74         static final int
     75                 SIGNED   = (-1) << KIND_SHIFT,
     76                 UNSIGNED = 0    << KIND_SHIFT,
     77                 FLOATING = 1    << KIND_SHIFT;
     78         static final int
     79                 SLOT_MASK = ((1<<(SIZE_SHIFT-SLOT_SHIFT))-1),
     80                 SIZE_MASK = ((1<<(KIND_SHIFT-SIZE_SHIFT))-1);
     81         static int format(int kind, int size, int slots) {
     82             assert(((kind >> KIND_SHIFT) << KIND_SHIFT) == kind);
     83             assert((size & (size-1)) == 0); // power of two
     84             assert((kind == SIGNED)   ? (size > 0) :
     85                    (kind == UNSIGNED) ? (size > 0) :
     86                    (kind == FLOATING) ? (size == 32 || size == 64)  :
     87                    false);
     88             assert((slots == 2) ? (size == 64) :
     89                    (slots == 1) ? (size <= 32) :
     90                    false);
     91             return kind | (size << SIZE_SHIFT) | (slots << SLOT_SHIFT);
     92         }
     93         static final int
     94                 INT      = SIGNED   | (32 << SIZE_SHIFT) | (1 << SLOT_SHIFT),
     95                 SHORT    = SIGNED   | (16 << SIZE_SHIFT) | (1 << SLOT_SHIFT),
     96                 BOOLEAN  = UNSIGNED | (1  << SIZE_SHIFT) | (1 << SLOT_SHIFT),
     97                 CHAR     = UNSIGNED | (16 << SIZE_SHIFT) | (1 << SLOT_SHIFT),
     98                 FLOAT    = FLOATING | (32 << SIZE_SHIFT) | (1 << SLOT_SHIFT),
     99                 VOID     = UNSIGNED | (0  << SIZE_SHIFT) | (0 << SLOT_SHIFT),
    100                 NUM_MASK = (-1) << SIZE_SHIFT;
    101         static int signed(int size)   { return format(SIGNED,   size, (size > 32 ? 2 : 1)); }
    102         static int unsigned(int size) { return format(UNSIGNED, size, (size > 32 ? 2 : 1)); }
    103         static int floating(int size) { return format(FLOATING, size, (size > 32 ? 2 : 1)); }
    104         static int other(int slots)   { return slots << SLOT_SHIFT; }
    105     }
    106 
    107     /// format queries:
    108 
    109     /** How many bits are in the wrapped value?  Returns 0 for OBJECT or VOID. */
    110     public int     bitWidth()      { return (format >> Format.SIZE_SHIFT) & Format.SIZE_MASK; }
    111     /** How many JVM stack slots occupied by the wrapped value?  Returns 0 for VOID. */
    112     public int     stackSlots()    { return (format >> Format.SLOT_SHIFT) & Format.SLOT_MASK; }
    113     /** Does the wrapped value occupy a single JVM stack slot? */
    114     public boolean isSingleWord()  { return (format & (1 << Format.SLOT_SHIFT)) != 0; }
    115     /** Does the wrapped value occupy two JVM stack slots? */
    116     public boolean isDoubleWord()  { return (format & (2 << Format.SLOT_SHIFT)) != 0; }
    117     /** Is the wrapped type numeric (not void or object)? */
    118     public boolean isNumeric()     { return (format & Format.NUM_MASK) != 0; }
    119     /** Is the wrapped type a primitive other than float, double, or void? */
    120     public boolean isIntegral()    { return isNumeric() && format < Format.FLOAT; }
    121     /** Is the wrapped type one of int, boolean, byte, char, or short? */
    122     public boolean isSubwordOrInt() { return isIntegral() && isSingleWord(); }
    123     /* Is the wrapped value a signed integral type (one of byte, short, int, or long)? */
    124     public boolean isSigned()      { return format < Format.VOID; }
    125     /* Is the wrapped value an unsigned integral type (one of boolean or char)? */
    126     public boolean isUnsigned()    { return format >= Format.BOOLEAN && format < Format.FLOAT; }
    127     /** Is the wrapped type either float or double? */
    128     public boolean isFloating()    { return format >= Format.FLOAT; }
    129     /** Is the wrapped type either void or a reference? */
    130     public boolean isOther()       { return (format & ~Format.SLOT_MASK) == 0; }
    131 
    132     /** Does the JLS 5.1.2 allow a variable of this wrapper's
    133      *  primitive type to be assigned from a value of the given wrapper's primitive type?
    134      *  Cases:
    135      *  <ul>
    136      *  <li>unboxing followed by widening primitive conversion
    137      *  <li>any type converted to {@code void} (i.e., dropping a method call's value)
    138      *  <li>boxing conversion followed by widening reference conversion to {@code Object}
    139      *  </ul>
    140      *  These are the cases allowed by MethodHandle.asType.
    141      */
    142     public boolean isConvertibleFrom(Wrapper source) {
    143         if (this == source)  return true;
    144         if (this.compareTo(source) < 0) {
    145             // At best, this is a narrowing conversion.
    146             return false;
    147         }
    148         // All conversions are allowed in the enum order between floats and signed ints.
    149         // First detect non-signed non-float types (boolean, char, Object, void).
    150         boolean floatOrSigned = (((this.format & source.format) & Format.SIGNED) != 0);
    151         if (!floatOrSigned) {
    152             if (this.isOther())  return true;
    153             // can convert char to int or wider, but nothing else
    154             if (source.format == Format.CHAR)  return true;
    155             // no other conversions are classified as widening
    156             return false;
    157         }
    158         // All signed and float conversions in the enum order are widening.
    159         assert(this.isFloating() || this.isSigned());
    160         assert(source.isFloating() || source.isSigned());
    161         return true;
    162     }
    163 
    164     static { assert(checkConvertibleFrom()); }
    165     private static boolean checkConvertibleFrom() {
    166         // Check the matrix for correct classification of widening conversions.
    167         for (Wrapper w : values()) {
    168             assert(w.isConvertibleFrom(w));
    169             assert(VOID.isConvertibleFrom(w));
    170             if (w != VOID) {
    171                 assert(OBJECT.isConvertibleFrom(w));
    172                 assert(!w.isConvertibleFrom(VOID));
    173             }
    174             // check relations with unsigned integral types:
    175             if (w != CHAR) {
    176                 assert(!CHAR.isConvertibleFrom(w));
    177                 if (!w.isConvertibleFrom(INT))
    178                     assert(!w.isConvertibleFrom(CHAR));
    179             }
    180             if (w != BOOLEAN) {
    181                 assert(!BOOLEAN.isConvertibleFrom(w));
    182                 if (w != VOID && w != OBJECT)
    183                     assert(!w.isConvertibleFrom(BOOLEAN));
    184             }
    185             // check relations with signed integral types:
    186             if (w.isSigned()) {
    187                 for (Wrapper x : values()) {
    188                     if (w == x)  continue;
    189                     if (x.isFloating())
    190                         assert(!w.isConvertibleFrom(x));
    191                     else if (x.isSigned()) {
    192                         if (w.compareTo(x) < 0)
    193                             assert(!w.isConvertibleFrom(x));
    194                         else
    195                             assert(w.isConvertibleFrom(x));
    196                     }
    197                 }
    198             }
    199             // check relations with floating types:
    200             if (w.isFloating()) {
    201                 for (Wrapper x : values()) {
    202                     if (w == x)  continue;
    203                     if (x.isSigned())
    204                         assert(w.isConvertibleFrom(x));
    205                     else if (x.isFloating()) {
    206                         if (w.compareTo(x) < 0)
    207                             assert(!w.isConvertibleFrom(x));
    208                         else
    209                             assert(w.isConvertibleFrom(x));
    210                     }
    211                 }
    212             }
    213         }
    214         return true;  // i.e., assert(true)
    215     }
    216 
    217     /** Produce a zero value for the given wrapper type.
    218      *  This will be a numeric zero for a number or character,
    219      *  false for a boolean, and null for a reference or void.
    220      *  The common thread is that this is what is contained
    221      *  in a default-initialized variable of the given primitive
    222      *  type.  (For void, it is what a reflective method returns
    223      *  instead of no value at all.)
    224      */
    225     public Object zero() { return zero; }
    226 
    227     /** Produce a zero value for the given wrapper type T.
    228      *  The optional argument must a type compatible with this wrapper.
    229      *  Equivalent to {@code this.cast(this.zero(), type)}.
    230      */
    231     public <T> T zero(Class<T> type) { return convert(zero, type); }
    232 
    233     /** Return the wrapper that wraps values of the given type.
    234      *  The type may be {@code Object}, meaning the {@code OBJECT} wrapper.
    235      *  Otherwise, the type must be a primitive.
    236      *  @throws IllegalArgumentException for unexpected types
    237      */
    238     public static Wrapper forPrimitiveType(Class<?> type) {
    239         Wrapper w = findPrimitiveType(type);
    240         if (w != null)  return w;
    241         if (type.isPrimitive())
    242             throw new InternalError(); // redo hash function
    243         throw newIllegalArgumentException("not primitive: "+type);
    244     }
    245 
    246     static Wrapper findPrimitiveType(Class<?> type) {
    247         Wrapper w = FROM_PRIM[hashPrim(type)];
    248         if (w != null && w.primitiveType == type) {
    249             return w;
    250         }
    251         return null;
    252     }
    253 
    254     /** Return the wrapper that wraps values into the given wrapper type.
    255      *  If it is {@code Object}, return {@code OBJECT}.
    256      *  Otherwise, it must be a wrapper type.
    257      *  The type must not be a primitive type.
    258      *  @throws IllegalArgumentException for unexpected types
    259      */
    260     public static Wrapper forWrapperType(Class<?> type) {
    261         Wrapper w = findWrapperType(type);
    262         if (w != null)  return w;
    263         for (Wrapper x : values())
    264             if (x.wrapperType == type)
    265                 throw new InternalError(); // redo hash function
    266         throw newIllegalArgumentException("not wrapper: "+type);
    267     }
    268 
    269     static Wrapper findWrapperType(Class<?> type) {
    270         Wrapper w = FROM_WRAP[hashWrap(type)];
    271         if (w != null && w.wrapperType == type) {
    272             return w;
    273         }
    274         return null;
    275     }
    276 
    277     /** Return the wrapper that corresponds to the given bytecode
    278      *  signature character.  Return {@code OBJECT} for the character 'L'.
    279      *  @throws IllegalArgumentException for any non-signature character or {@code '['}.
    280      */
    281     public static Wrapper forBasicType(char type) {
    282         Wrapper w = FROM_CHAR[hashChar(type)];
    283         if (w != null && w.basicTypeChar == type) {
    284             return w;
    285         }
    286         for (Wrapper x : values())
    287             if (w.basicTypeChar == type)
    288                 throw new InternalError(); // redo hash function
    289         throw newIllegalArgumentException("not basic type char: "+type);
    290     }
    291 
    292     /** Return the wrapper for the given type, if it is
    293      *  a primitive type, else return {@code OBJECT}.
    294      */
    295     public static Wrapper forBasicType(Class<?> type) {
    296         if (type.isPrimitive())
    297             return forPrimitiveType(type);
    298         return OBJECT;  // any reference, including wrappers or arrays
    299     }
    300 
    301     // Note on perfect hashes:
    302     //   for signature chars c, do (c + (c >> 1)) % 16
    303     //   for primitive type names n, do (n[0] + n[2]) % 16
    304     // The type name hash works for both primitive and wrapper names.
    305     // You can add "java/lang/Object" to the primitive names.
    306     // But you add the wrapper name Object, use (n[2] + (3*n[1])) % 16.
    307     private static final Wrapper[] FROM_PRIM = new Wrapper[16];
    308     private static final Wrapper[] FROM_WRAP = new Wrapper[16];
    309     private static final Wrapper[] FROM_CHAR = new Wrapper[16];
    310     private static int hashPrim(Class<?> x) {
    311         String xn = x.getName();
    312         if (xn.length() < 3)  return 0;
    313         return (xn.charAt(0) + xn.charAt(2)) % 16;
    314     }
    315     private static int hashWrap(Class<?> x) {
    316         String xn = x.getName();
    317         final int offset = 10; assert(offset == "java.lang.".length());
    318         if (xn.length() < offset+3)  return 0;
    319         return (3*xn.charAt(offset+1) + xn.charAt(offset+2)) % 16;
    320     }
    321     private static int hashChar(char x) {
    322         return (x + (x >> 1)) % 16;
    323     }
    324     static {
    325         for (Wrapper w : values()) {
    326             int pi = hashPrim(w.primitiveType);
    327             int wi = hashWrap(w.wrapperType);
    328             int ci = hashChar(w.basicTypeChar);
    329             assert(FROM_PRIM[pi] == null);
    330             assert(FROM_WRAP[wi] == null);
    331             assert(FROM_CHAR[ci] == null);
    332             FROM_PRIM[pi] = w;
    333             FROM_WRAP[wi] = w;
    334             FROM_CHAR[ci] = w;
    335         }
    336         //assert(jdk.sun.invoke.util.WrapperTest.test(false));
    337     }
    338 
    339     /** What is the primitive type wrapped by this wrapper? */
    340     public Class<?> primitiveType() { return primitiveType; }
    341 
    342     /** What is the wrapper type for this wrapper? */
    343     public Class<?> wrapperType() { return wrapperType; }
    344 
    345     /** What is the wrapper type for this wrapper?
    346      * Otherwise, the example type must be the wrapper type,
    347      * or the corresponding primitive type.
    348      * (For {@code OBJECT}, the example type can be any non-primitive,
    349      * and is normalized to {@code Object.class}.)
    350      * The resulting class type has the same type parameter.
    351      */
    352     public <T> Class<T> wrapperType(Class<T> exampleType) {
    353         if (exampleType == wrapperType) {
    354             return exampleType;
    355         } else if (exampleType == primitiveType ||
    356                    wrapperType == Object.class ||
    357                    exampleType.isInterface()) {
    358             return forceType(wrapperType, exampleType);
    359         }
    360         throw newClassCastException(exampleType, primitiveType);
    361     }
    362 
    363     private static ClassCastException newClassCastException(Class<?> actual, Class<?> expected) {
    364         return new ClassCastException(actual + " is not compatible with " + expected);
    365     }
    366 
    367     /** If {@code type} is a primitive type, return the corresponding
    368      *  wrapper type, else return {@code type} unchanged.
    369      */
    370     public static <T> Class<T> asWrapperType(Class<T> type) {
    371         if (type.isPrimitive()) {
    372             return forPrimitiveType(type).wrapperType(type);
    373         }
    374         return type;
    375     }
    376 
    377     /** If {@code type} is a wrapper type, return the corresponding
    378      *  primitive type, else return {@code type} unchanged.
    379      */
    380     public static <T> Class<T> asPrimitiveType(Class<T> type) {
    381         Wrapper w = findWrapperType(type);
    382         if (w != null) {
    383             return forceType(w.primitiveType(), type);
    384         }
    385         return type;
    386     }
    387 
    388     /** Query:  Is the given type a wrapper, such as {@code Integer} or {@code Void}? */
    389     public static boolean isWrapperType(Class<?> type) {
    390         return findWrapperType(type) != null;
    391     }
    392 
    393     /** Query:  Is the given type a primitive, such as {@code int} or {@code void}? */
    394     public static boolean isPrimitiveType(Class<?> type) {
    395         return type.isPrimitive();
    396     }
    397 
    398     /** What is the bytecode signature character for this type?
    399      *  All non-primitives, including array types, report as 'L', the signature character for references.
    400      */
    401     public static char basicTypeChar(Class<?> type) {
    402         if (!type.isPrimitive())
    403             return 'L';
    404         else
    405             return forPrimitiveType(type).basicTypeChar();
    406     }
    407 
    408     /** What is the bytecode signature character for this wrapper's
    409      *  primitive type?
    410      */
    411     public char basicTypeChar() { return basicTypeChar; }
    412 
    413     /** What is the simple name of the wrapper type?
    414      */
    415     public String wrapperSimpleName() { return wrapperSimpleName; }
    416 
    417     /** What is the simple name of the primitive type?
    418      */
    419     public String primitiveSimpleName() { return primitiveSimpleName; }
    420 
    421 //    /** Wrap a value in the given type, which may be either a primitive or wrapper type.
    422 //     *  Performs standard primitive conversions, including truncation and float conversions.
    423 //     */
    424 //    public static <T> T wrap(Object x, Class<T> type) {
    425 //        return Wrapper.valueOf(type).cast(x, type);
    426 //    }
    427 
    428     /** Cast a wrapped value to the given type, which may be either a primitive or wrapper type.
    429      *  The given target type must be this wrapper's primitive or wrapper type.
    430      *  If this wrapper is OBJECT, the target type may also be an interface, perform no runtime check.
    431      *  Performs standard primitive conversions, including truncation and float conversions.
    432      *  The given type must be compatible with this wrapper.  That is, it must either
    433      *  be the wrapper type (or a subtype, in the case of {@code OBJECT}) or else
    434      *  it must be the wrapper's primitive type.
    435      *  Primitive conversions are only performed if the given type is itself a primitive.
    436      *  @throws ClassCastException if the given type is not compatible with this wrapper
    437      */
    438     public <T> T cast(Object x, Class<T> type) {
    439         return convert(x, type, true);
    440     }
    441 
    442     /** Convert a wrapped value to the given type.
    443      *  The given target type must be this wrapper's primitive or wrapper type.
    444      *  This is equivalent to {@link #cast}, except that it refuses to perform
    445      *  narrowing primitive conversions.
    446      */
    447     public <T> T convert(Object x, Class<T> type) {
    448         return convert(x, type, false);
    449     }
    450 
    451     private <T> T convert(Object x, Class<T> type, boolean isCast) {
    452         if (this == OBJECT) {
    453             // If the target wrapper is OBJECT, just do a reference cast.
    454             // If the target type is an interface, perform no runtime check.
    455             // (This loophole is safe, and is allowed by the JVM verifier.)
    456             // If the target type is a primitive, change it to a wrapper.
    457             assert(!type.isPrimitive());
    458             if (!type.isInterface())
    459                 type.cast(x);
    460             @SuppressWarnings("unchecked")
    461             T result = (T) x;  // unchecked warning is expected here
    462             return result;
    463         }
    464         Class<T> wtype = wrapperType(type);
    465         if (wtype.isInstance(x)) {
    466             return wtype.cast(x);
    467         }
    468         if (!isCast) {
    469             Class<?> sourceType = x.getClass();  // throw NPE if x is null
    470             Wrapper source = findWrapperType(sourceType);
    471             if (source == null || !this.isConvertibleFrom(source)) {
    472                 throw newClassCastException(wtype, sourceType);
    473             }
    474         } else if (x == null) {
    475             @SuppressWarnings("unchecked")
    476             T z = (T) zero;
    477             return z;
    478         }
    479         @SuppressWarnings("unchecked")
    480         T result = (T) wrap(x);  // unchecked warning is expected here
    481         assert (result == null ? Void.class : result.getClass()) == wtype;
    482         return result;
    483     }
    484 
    485     /** Cast a reference type to another reference type.
    486      * If the target type is an interface, perform no runtime check.
    487      * (This loophole is safe, and is allowed by the JVM verifier.)
    488      * If the target type is a primitive, change it to a wrapper.
    489      */
    490     static <T> Class<T> forceType(Class<?> type, Class<T> exampleType) {
    491         boolean z = (type == exampleType ||
    492                type.isPrimitive() && forPrimitiveType(type) == findWrapperType(exampleType) ||
    493                exampleType.isPrimitive() && forPrimitiveType(exampleType) == findWrapperType(type) ||
    494                type == Object.class && !exampleType.isPrimitive());
    495         if (!z)
    496             System.out.println(type+" <= "+exampleType);
    497         assert(type == exampleType ||
    498                type.isPrimitive() && forPrimitiveType(type) == findWrapperType(exampleType) ||
    499                exampleType.isPrimitive() && forPrimitiveType(exampleType) == findWrapperType(type) ||
    500                type == Object.class && !exampleType.isPrimitive());
    501         @SuppressWarnings("unchecked")
    502         Class<T> result = (Class<T>) type;  // unchecked warning is expected here
    503         return result;
    504     }
    505 
    506     /** Wrap a value in this wrapper's type.
    507      * Performs standard primitive conversions, including truncation and float conversions.
    508      * Performs returns the unchanged reference for {@code OBJECT}.
    509      * Returns null for {@code VOID}.
    510      * Returns a zero value for a null input.
    511      * @throws ClassCastException if this wrapper is numeric and the operand
    512      *                            is not a number, character, boolean, or null
    513      */
    514     public Object wrap(Object x) {
    515         // do non-numeric wrappers first
    516         switch (basicTypeChar) {
    517             case 'L': return x;
    518             case 'V': return null;
    519         }
    520         Number xn = numberValue(x);
    521         switch (basicTypeChar) {
    522             case 'I': return Integer.valueOf(xn.intValue());
    523             case 'J': return Long.valueOf(xn.longValue());
    524             case 'F': return Float.valueOf(xn.floatValue());
    525             case 'D': return Double.valueOf(xn.doubleValue());
    526             case 'S': return Short.valueOf((short) xn.intValue());
    527             case 'B': return Byte.valueOf((byte) xn.intValue());
    528             case 'C': return Character.valueOf((char) xn.intValue());
    529             case 'Z': return Boolean.valueOf(boolValue(xn.byteValue()));
    530         }
    531         throw new InternalError("bad wrapper");
    532     }
    533 
    534     /** Wrap a value (an int or smaller value) in this wrapper's type.
    535      * Performs standard primitive conversions, including truncation and float conversions.
    536      * Produces an {@code Integer} for {@code OBJECT}, although the exact type
    537      * of the operand is not known.
    538      * Returns null for {@code VOID}.
    539      */
    540     public Object wrap(int x) {
    541         if (basicTypeChar == 'L')  return (Integer)x;
    542         switch (basicTypeChar) {
    543             case 'L': throw newIllegalArgumentException("cannot wrap to object type");
    544             case 'V': return null;
    545             case 'I': return Integer.valueOf(x);
    546             case 'J': return Long.valueOf(x);
    547             case 'F': return Float.valueOf(x);
    548             case 'D': return Double.valueOf(x);
    549             case 'S': return Short.valueOf((short) x);
    550             case 'B': return Byte.valueOf((byte) x);
    551             case 'C': return Character.valueOf((char) x);
    552             case 'Z': return Boolean.valueOf(boolValue((byte) x));
    553         }
    554         throw new InternalError("bad wrapper");
    555     }
    556 
    557     private static Number numberValue(Object x) {
    558         if (x instanceof Number)     return (Number)x;
    559         if (x instanceof Character)  return (int)(Character)x;
    560         if (x instanceof Boolean)    return (Boolean)x ? 1 : 0;
    561         // Remaining allowed case of void:  Must be a null reference.
    562         return (Number)x;
    563     }
    564 
    565     // Parameter type of boolValue must be byte, because
    566     // MethodHandles.explicitCastArguments defines boolean
    567     // conversion as first converting to byte.
    568     private static boolean boolValue(byte bits) {
    569         bits &= 1;  // simple 31-bit zero extension
    570         return (bits != 0);
    571     }
    572 
    573     private static RuntimeException newIllegalArgumentException(String message, Object x) {
    574         return newIllegalArgumentException(message + x);
    575     }
    576     private static RuntimeException newIllegalArgumentException(String message) {
    577         return new IllegalArgumentException(message);
    578     }
    579 
    580     // primitive array support
    581     public Object makeArray(int len) {
    582         return java.lang.reflect.Array.newInstance(primitiveType, len);
    583     }
    584     public Class<?> arrayType() {
    585         return emptyArray.getClass();
    586     }
    587     public void copyArrayUnboxing(Object[] values, int vpos, Object a, int apos, int length) {
    588         if (a.getClass() != arrayType())
    589             arrayType().cast(a);  // throw NPE or CCE if bad type
    590         for (int i = 0; i < length; i++) {
    591             Object value = values[i+vpos];
    592             value = convert(value, primitiveType);
    593             java.lang.reflect.Array.set(a, i+apos, value);
    594         }
    595     }
    596     public void copyArrayBoxing(Object a, int apos, Object[] values, int vpos, int length) {
    597         if (a.getClass() != arrayType())
    598             arrayType().cast(a);  // throw NPE or CCE if bad type
    599         for (int i = 0; i < length; i++) {
    600             Object value = java.lang.reflect.Array.get(a, i+apos);
    601             //Already done: value = convert(value, primitiveType);
    602             assert(value.getClass() == wrapperType);
    603             values[i+vpos] = value;
    604         }
    605     }
    606 }
    607