/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.google.gwt.dev.asm;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

/**
 * A Java type. This class can be used to make it easier to manipulate type and
 * method descriptors.
 * 
 * @author Eric Bruneton
 * @author Chris Nokleberg
 */
public class Type {

    /**
     * The sort of the <tt>void</tt> type. See {@link #getSort getSort}.
     */
    public static final int VOID = 0;

    /**
     * The sort of the <tt>boolean</tt> type. See {@link #getSort getSort}.
     */
    public static final int BOOLEAN = 1;

    /**
     * The sort of the <tt>char</tt> type. See {@link #getSort getSort}.
     */
    public static final int CHAR = 2;

    /**
     * The sort of the <tt>byte</tt> type. See {@link #getSort getSort}.
     */
    public static final int BYTE = 3;

    /**
     * The sort of the <tt>short</tt> type. See {@link #getSort getSort}.
     */
    public static final int SHORT = 4;

    /**
     * The sort of the <tt>int</tt> type. See {@link #getSort getSort}.
     */
    public static final int INT = 5;

    /**
     * The sort of the <tt>float</tt> type. See {@link #getSort getSort}.
     */
    public static final int FLOAT = 6;

    /**
     * The sort of the <tt>long</tt> type. See {@link #getSort getSort}.
     */
    public static final int LONG = 7;

    /**
     * The sort of the <tt>double</tt> type. See {@link #getSort getSort}.
     */
    public static final int DOUBLE = 8;

    /**
     * The sort of array reference types. See {@link #getSort getSort}.
     */
    public static final int ARRAY = 9;

    /**
     * The sort of object reference type. See {@link #getSort getSort}.
     */
    public static final int OBJECT = 10;

    /**
     * The <tt>void</tt> type.
     */
    public static final Type VOID_TYPE = new Type(VOID);

    /**
     * The <tt>boolean</tt> type.
     */
    public static final Type BOOLEAN_TYPE = new Type(BOOLEAN);

    /**
     * The <tt>char</tt> type.
     */
    public static final Type CHAR_TYPE = new Type(CHAR);

    /**
     * The <tt>byte</tt> type.
     */
    public static final Type BYTE_TYPE = new Type(BYTE);

    /**
     * The <tt>short</tt> type.
     */
    public static final Type SHORT_TYPE = new Type(SHORT);

    /**
     * The <tt>int</tt> type.
     */
    public static final Type INT_TYPE = new Type(INT);

    /**
     * The <tt>float</tt> type.
     */
    public static final Type FLOAT_TYPE = new Type(FLOAT);

    /**
     * The <tt>long</tt> type.
     */
    public static final Type LONG_TYPE = new Type(LONG);

    /**
     * The <tt>double</tt> type.
     */
    public static final Type DOUBLE_TYPE = new Type(DOUBLE);

    // ------------------------------------------------------------------------
    // Fields
    // ------------------------------------------------------------------------

    /**
     * The sort of this Java type.
     */
    private final int sort;

    /**
     * A buffer containing the internal name of this Java type. This field is
     * only used for reference types.
     */
    private final char[] buf;

    /**
     * The offset of the internal name of this Java type in {@link #buf buf}.
     * This field is only used for reference types.
     */
    private final int off;

    /**
     * The length of the internal name of this Java type. This field is only
     * used for reference types.
     */
    private final int len;

    // ------------------------------------------------------------------------
    // Constructors
    // ------------------------------------------------------------------------

    /**
     * Constructs a primitive type.
     * 
     * @param sort the sort of the primitive type to be constructed.
     */
    private Type(final int sort) {
        this(sort, null, 0, 1);
    }

    /**
     * Constructs a reference type.
     * 
     * @param sort the sort of the reference type to be constructed.
     * @param buf a buffer containing the descriptor of the previous type.
     * @param off the offset of this descriptor in the previous buffer.
     * @param len the length of this descriptor.
     */
    private Type(final int sort, final char[] buf, final int off, final int len)
    {
        this.sort = sort;
        this.buf = buf;
        this.off = off;
        this.len = len;
    }

    /**
     * Returns the Java type corresponding to the given type descriptor.
     * 
     * @param typeDescriptor a type descriptor.
     * @return the Java type corresponding to the given type descriptor.
     */
    public static Type getType(final String typeDescriptor) {
        return getType(typeDescriptor.toCharArray(), 0);
    }

    /**
     * Returns the Java type corresponding to the given internal name.
     * 
     * @param internalName an internal name.
     * @return the Java type corresponding to the given internal name.
     */
    public static Type getObjectType(final String internalName) {
        char[] buf = internalName.toCharArray();
        return new Type(buf[0] == '[' ? ARRAY : OBJECT, buf, 0, buf.length);
    }

    /**
     * Returns the Java type corresponding to the given class.
     * 
     * @param c a class.
     * @return the Java type corresponding to the given class.
     */
    public static Type getType(final Class c) {
        if (c.isPrimitive()) {
            if (c == Integer.TYPE) {
                return INT_TYPE;
            } else if (c == Void.TYPE) {
                return VOID_TYPE;
            } else if (c == Boolean.TYPE) {
                return BOOLEAN_TYPE;
            } else if (c == Byte.TYPE) {
                return BYTE_TYPE;
            } else if (c == Character.TYPE) {
                return CHAR_TYPE;
            } else if (c == Short.TYPE) {
                return SHORT_TYPE;
            } else if (c == Double.TYPE) {
                return DOUBLE_TYPE;
            } else if (c == Float.TYPE) {
                return FLOAT_TYPE;
            } else /* if (c == Long.TYPE) */{
                return LONG_TYPE;
            }
        } else {
            return getType(getDescriptor(c));
        }
    }

    /**
     * Returns the Java types corresponding to the argument types of the given
     * method descriptor.
     * 
     * @param methodDescriptor a method descriptor.
     * @return the Java types corresponding to the argument types of the given
     *         method descriptor.
     */
    public static Type[] getArgumentTypes(final String methodDescriptor) {
        char[] buf = methodDescriptor.toCharArray();
        int off = 1;
        int size = 0;
        while (true) {
            char car = buf[off++];
            if (car == ')') {
                break;
            } else if (car == 'L') {
                while (buf[off++] != ';') {
                }
                ++size;
            } else if (car != '[') {
                ++size;
            }
        }
        Type[] args = new Type[size];
        off = 1;
        size = 0;
        while (buf[off] != ')') {
            args[size] = getType(buf, off);
            off += args[size].len + (args[size].sort == OBJECT ? 2 : 0);
            size += 1;
        }
        return args;
    }

    /**
     * Returns the Java types corresponding to the argument types of the given
     * method.
     * 
     * @param method a method.
     * @return the Java types corresponding to the argument types of the given
     *         method.
     */
    public static Type[] getArgumentTypes(final Method method) {
        Class[] classes = method.getParameterTypes();
        Type[] types = new Type[classes.length];
        for (int i = classes.length - 1; i >= 0; --i) {
            types[i] = getType(classes[i]);
        }
        return types;
    }

    /**
     * Returns the Java type corresponding to the return type of the given
     * method descriptor.
     * 
     * @param methodDescriptor a method descriptor.
     * @return the Java type corresponding to the return type of the given
     *         method descriptor.
     */
    public static Type getReturnType(final String methodDescriptor) {
        char[] buf = methodDescriptor.toCharArray();
        return getType(buf, methodDescriptor.indexOf(')') + 1);
    }

    /**
     * Returns the Java type corresponding to the return type of the given
     * method.
     * 
     * @param method a method.
     * @return the Java type corresponding to the return type of the given
     *         method.
     */
    public static Type getReturnType(final Method method) {
        return getType(method.getReturnType());
    }

    /**
     * Returns the Java type corresponding to the given type descriptor.
     * 
     * @param buf a buffer containing a type descriptor.
     * @param off the offset of this descriptor in the previous buffer.
     * @return the Java type corresponding to the given type descriptor.
     */
    private static Type getType(final char[] buf, final int off) {
        int len;
        switch (buf[off]) {
            case 'V':
                return VOID_TYPE;
            case 'Z':
                return BOOLEAN_TYPE;
            case 'C':
                return CHAR_TYPE;
            case 'B':
                return BYTE_TYPE;
            case 'S':
                return SHORT_TYPE;
            case 'I':
                return INT_TYPE;
            case 'F':
                return FLOAT_TYPE;
            case 'J':
                return LONG_TYPE;
            case 'D':
                return DOUBLE_TYPE;
            case '[':
                len = 1;
                while (buf[off + len] == '[') {
                    ++len;
                }
                if (buf[off + len] == 'L') {
                    ++len;
                    while (buf[off + len] != ';') {
                        ++len;
                    }
                }
                return new Type(ARRAY, buf, off, len + 1);
                // case 'L':
            default:
                len = 1;
                while (buf[off + len] != ';') {
                    ++len;
                }
                return new Type(OBJECT, buf, off + 1, len - 1);
        }
    }

    // ------------------------------------------------------------------------
    // Accessors
    // ------------------------------------------------------------------------

    /**
     * Returns the sort of this Java type.
     * 
     * @return {@link #VOID VOID}, {@link #BOOLEAN BOOLEAN},
     *         {@link #CHAR CHAR}, {@link #BYTE BYTE}, {@link #SHORT SHORT},
     *         {@link #INT INT}, {@link #FLOAT FLOAT}, {@link #LONG LONG},
     *         {@link #DOUBLE DOUBLE}, {@link #ARRAY ARRAY} or
     *         {@link #OBJECT OBJECT}.
     */
    public int getSort() {
        return sort;
    }

    /**
     * Returns the number of dimensions of this array type. This method should
     * only be used for an array type.
     * 
     * @return the number of dimensions of this array type.
     */
    public int getDimensions() {
        int i = 1;
        while (buf[off + i] == '[') {
            ++i;
        }
        return i;
    }

    /**
     * Returns the type of the elements of this array type. This method should
     * only be used for an array type.
     * 
     * @return Returns the type of the elements of this array type.
     */
    public Type getElementType() {
        return getType(buf, off + getDimensions());
    }

    /**
     * Returns the name of the class corresponding to this type.
     * 
     * @return the fully qualified name of the class corresponding to this type.
     */
    public String getClassName() {
        switch (sort) {
            case VOID:
                return "void";
            case BOOLEAN:
                return "boolean";
            case CHAR:
                return "char";
            case BYTE:
                return "byte";
            case SHORT:
                return "short";
            case INT:
                return "int";
            case FLOAT:
                return "float";
            case LONG:
                return "long";
            case DOUBLE:
                return "double";
            case ARRAY:
                StringBuffer b = new StringBuffer(getElementType().getClassName());
                for (int i = getDimensions(); i > 0; --i) {
                    b.append("[]");
                }
                return b.toString();
                // case OBJECT:
            default:
                return new String(buf, off, len).replace('/', '.');
        }
    }

    /**
     * Returns the internal name of the class corresponding to this object or
     * array type. The internal name of a class is its fully qualified name (as
     * returned by Class.getName(), where '.' are replaced by '/'. This method
     * should only be used for an object or array type.
     * 
     * @return the internal name of the class corresponding to this object type.
     */
    public String getInternalName() {
        return new String(buf, off, len);
    }

    // ------------------------------------------------------------------------
    // Conversion to type descriptors
    // ------------------------------------------------------------------------

    /**
     * Returns the descriptor corresponding to this Java type.
     * 
     * @return the descriptor corresponding to this Java type.
     */
    public String getDescriptor() {
        StringBuffer buf = new StringBuffer();
        getDescriptor(buf);
        return buf.toString();
    }

    /**
     * Returns the descriptor corresponding to the given argument and return
     * types.
     * 
     * @param returnType the return type of the method.
     * @param argumentTypes the argument types of the method.
     * @return the descriptor corresponding to the given argument and return
     *         types.
     */
    public static String getMethodDescriptor(
        final Type returnType,
        final Type[] argumentTypes)
    {
        StringBuffer buf = new StringBuffer();
        buf.append('(');
        for (int i = 0; i < argumentTypes.length; ++i) {
            argumentTypes[i].getDescriptor(buf);
        }
        buf.append(')');
        returnType.getDescriptor(buf);
        return buf.toString();
    }

    /**
     * Appends the descriptor corresponding to this Java type to the given
     * string buffer.
     * 
     * @param buf the string buffer to which the descriptor must be appended.
     */
    private void getDescriptor(final StringBuffer buf) {
        switch (sort) {
            case VOID:
                buf.append('V');
                return;
            case BOOLEAN:
                buf.append('Z');
                return;
            case CHAR:
                buf.append('C');
                return;
            case BYTE:
                buf.append('B');
                return;
            case SHORT:
                buf.append('S');
                return;
            case INT:
                buf.append('I');
                return;
            case FLOAT:
                buf.append('F');
                return;
            case LONG:
                buf.append('J');
                return;
            case DOUBLE:
                buf.append('D');
                return;
            case ARRAY:
                buf.append(this.buf, off, len);
                return;
                // case OBJECT:
            default:
                buf.append('L');
                buf.append(this.buf, off, len);
                buf.append(';');
        }
    }

    // ------------------------------------------------------------------------
    // Direct conversion from classes to type descriptors,
    // without intermediate Type objects
    // ------------------------------------------------------------------------

    /**
     * Returns the internal name of the given class. The internal name of a
     * class is its fully qualified name, as returned by Class.getName(), where
     * '.' are replaced by '/'.
     * 
     * @param c an object or array class.
     * @return the internal name of the given class.
     */
    public static String getInternalName(final Class c) {
        return c.getName().replace('.', '/');
    }

    /**
     * Returns the descriptor corresponding to the given Java type.
     * 
     * @param c an object class, a primitive class or an array class.
     * @return the descriptor corresponding to the given class.
     */
    public static String getDescriptor(final Class c) {
        StringBuffer buf = new StringBuffer();
        getDescriptor(buf, c);
        return buf.toString();
    }

    /**
     * Returns the descriptor corresponding to the given constructor.
     * 
     * @param c a {@link Constructor Constructor} object.
     * @return the descriptor of the given constructor.
     */
    public static String getConstructorDescriptor(final Constructor c) {
        Class[] parameters = c.getParameterTypes();
        StringBuffer buf = new StringBuffer();
        buf.append('(');
        for (int i = 0; i < parameters.length; ++i) {
            getDescriptor(buf, parameters[i]);
        }
        return buf.append(")V").toString();
    }

    /**
     * Returns the descriptor corresponding to the given method.
     * 
     * @param m a {@link Method Method} object.
     * @return the descriptor of the given method.
     */
    public static String getMethodDescriptor(final Method m) {
        Class[] parameters = m.getParameterTypes();
        StringBuffer buf = new StringBuffer();
        buf.append('(');
        for (int i = 0; i < parameters.length; ++i) {
            getDescriptor(buf, parameters[i]);
        }
        buf.append(')');
        getDescriptor(buf, m.getReturnType());
        return buf.toString();
    }

    /**
     * Appends the descriptor of the given class to the given string buffer.
     * 
     * @param buf the string buffer to which the descriptor must be appended.
     * @param c the class whose descriptor must be computed.
     */
    private static void getDescriptor(final StringBuffer buf, final Class c) {
        Class d = c;
        while (true) {
            if (d.isPrimitive()) {
                char car;
                if (d == Integer.TYPE) {
                    car = 'I';
                } else if (d == Void.TYPE) {
                    car = 'V';
                } else if (d == Boolean.TYPE) {
                    car = 'Z';
                } else if (d == Byte.TYPE) {
                    car = 'B';
                } else if (d == Character.TYPE) {
                    car = 'C';
                } else if (d == Short.TYPE) {
                    car = 'S';
                } else if (d == Double.TYPE) {
                    car = 'D';
                } else if (d == Float.TYPE) {
                    car = 'F';
                } else /* if (d == Long.TYPE) */{
                    car = 'J';
                }
                buf.append(car);
                return;
            } else if (d.isArray()) {
                buf.append('[');
                d = d.getComponentType();
            } else {
                buf.append('L');
                String name = d.getName();
                int len = name.length();
                for (int i = 0; i < len; ++i) {
                    char car = name.charAt(i);
                    buf.append(car == '.' ? '/' : car);
                }
                buf.append(';');
                return;
            }
        }
    }

    // ------------------------------------------------------------------------
    // Corresponding size and opcodes
    // ------------------------------------------------------------------------

    /**
     * Returns the size of values of this type.
     * 
     * @return the size of values of this type, i.e., 2 for <tt>long</tt> and
     *         <tt>double</tt>, and 1 otherwise.
     */
    public int getSize() {
        return sort == LONG || sort == DOUBLE ? 2 : 1;
    }

    /**
     * Returns a JVM instruction opcode adapted to this Java type.
     * 
     * @param opcode a JVM instruction opcode. This opcode must be one of ILOAD,
     *        ISTORE, IALOAD, IASTORE, IADD, ISUB, IMUL, IDIV, IREM, INEG, ISHL,
     *        ISHR, IUSHR, IAND, IOR, IXOR and IRETURN.
     * @return an opcode that is similar to the given opcode, but adapted to
     *         this Java type. For example, if this type is <tt>float</tt> and
     *         <tt>opcode</tt> is IRETURN, this method returns FRETURN.
     */
    public int getOpcode(final int opcode) {
        if (opcode == Opcodes.IALOAD || opcode == Opcodes.IASTORE) {
            switch (sort) {
                case BOOLEAN:
                case BYTE:
                    return opcode + 5;
                case CHAR:
                    return opcode + 6;
                case SHORT:
                    return opcode + 7;
                case INT:
                    return opcode;
                case FLOAT:
                    return opcode + 2;
                case LONG:
                    return opcode + 1;
                case DOUBLE:
                    return opcode + 3;
                    // case ARRAY:
                    // case OBJECT:
                default:
                    return opcode + 4;
            }
        } else {
            switch (sort) {
                case VOID:
                    return opcode + 5;
                case BOOLEAN:
                case CHAR:
                case BYTE:
                case SHORT:
                case INT:
                    return opcode;
                case FLOAT:
                    return opcode + 2;
                case LONG:
                    return opcode + 1;
                case DOUBLE:
                    return opcode + 3;
                    // case ARRAY:
                    // case OBJECT:
                default:
                    return opcode + 4;
            }
        }
    }

    // ------------------------------------------------------------------------
    // Equals, hashCode and toString
    // ------------------------------------------------------------------------

    /**
     * Tests if the given object is equal to this type.
     * 
     * @param o the object to be compared to this type.
     * @return <tt>true</tt> if the given object is equal to this type.
     */
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (!(o instanceof Type)) {
            return false;
        }
        Type t = (Type) o;
        if (sort != t.sort) {
            return false;
        }
        if (sort == OBJECT || sort == ARRAY) {
            if (len != t.len) {
                return false;
            }
            for (int i = off, j = t.off, end = i + len; i < end; i++, j++) {
                if (buf[i] != t.buf[j]) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Returns a hash code value for this type.
     * 
     * @return a hash code value for this type.
     */
    public int hashCode() {
        int hc = 13 * sort;
        if (sort == OBJECT || sort == ARRAY) {
            for (int i = off, end = i + len; i < end; i++) {
                hc = 17 * (hc + buf[i]);
            }
        }
        return hc;
    }

    /**
     * Returns a string representation of this type.
     * 
     * @return the descriptor of this type.
     */
    public String toString() {
        return getDescriptor();
    }
}