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// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 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 org.objectweb.asm;
/**
* The path to a type argument, wildcard bound, array element type, or static inner type within an
* enclosing type.
*
* @author Eric Bruneton
*/
public final class TypePath {
/** A type path step that steps into the element type of an array type. See {@link #getStep}. */
public static final int ARRAY_ELEMENT = 0;
/** A type path step that steps into the nested type of a class type. See {@link #getStep}. */
public static final int INNER_TYPE = 1;
/** A type path step that steps into the bound of a wildcard type. See {@link #getStep}. */
public static final int WILDCARD_BOUND = 2;
/** A type path step that steps into a type argument of a generic type. See {@link #getStep}. */
public static final int TYPE_ARGUMENT = 3;
/**
* The byte array where the 'type_path' structure - as defined in the Java Virtual Machine
* Specification (JVMS) - corresponding to this TypePath is stored. The first byte of the
* structure in this array is given by {@link #typePathOffset}.
*
* @see <a
* href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.20.2">JVMS
* 4.7.20.2</a>
*/
private final byte[] typePathContainer;
/** The offset of the first byte of the type_path JVMS structure in {@link #typePathContainer}. */
private final int typePathOffset;
/**
* Constructs a new TypePath.
*
* @param typePathContainer a byte array containing a type_path JVMS structure.
* @param typePathOffset the offset of the first byte of the type_path structure in
* typePathContainer.
*/
TypePath(final byte[] typePathContainer, final int typePathOffset) {
this.typePathContainer = typePathContainer;
this.typePathOffset = typePathOffset;
}
/**
* Returns the length of this path, i.e. its number of steps.
*
* @return the length of this path.
*/
public int getLength() {
// path_length is stored in the first byte of a type_path.
return typePathContainer[typePathOffset];
}
/**
* Returns the value of the given step of this path.
*
* @param index an index between 0 and {@link #getLength()}, exclusive.
* @return one of {@link #ARRAY_ELEMENT}, {@link #INNER_TYPE}, {@link #WILDCARD_BOUND}, or {@link
* #TYPE_ARGUMENT}.
*/
public int getStep(final int index) {
// Returns the type_path_kind of the path element of the given index.
return typePathContainer[typePathOffset + 2 * index + 1];
}
/**
* Returns the index of the type argument that the given step is stepping into. This method should
* only be used for steps whose value is {@link #TYPE_ARGUMENT}.
*
* @param index an index between 0 and {@link #getLength()}, exclusive.
* @return the index of the type argument that the given step is stepping into.
*/
public int getStepArgument(final int index) {
// Returns the type_argument_index of the path element of the given index.
return typePathContainer[typePathOffset + 2 * index + 2];
}
/**
* Converts a type path in string form, in the format used by {@link #toString()}, into a TypePath
* object.
*
* @param typePath a type path in string form, in the format used by {@link #toString()}. May be
* {@literal null} or empty.
* @return the corresponding TypePath object, or {@literal null} if the path is empty.
*/
public static TypePath fromString(final String typePath) {
if (typePath == null || typePath.length() == 0) {
return null;
}
int typePathLength = typePath.length();
ByteVector output = new ByteVector(typePathLength);
output.putByte(0);
int typePathIndex = 0;
while (typePathIndex < typePathLength) {
char c = typePath.charAt(typePathIndex++);
if (c == '[') {
output.put11(ARRAY_ELEMENT, 0);
} else if (c == '.') {
output.put11(INNER_TYPE, 0);
} else if (c == '*') {
output.put11(WILDCARD_BOUND, 0);
} else if (c >= '0' && c <= '9') {
int typeArg = c - '0';
while (typePathIndex < typePathLength) {
c = typePath.charAt(typePathIndex++);
if (c >= '0' && c <= '9') {
typeArg = typeArg * 10 + c - '0';
} else if (c == ';') {
break;
} else {
throw new IllegalArgumentException();
}
}
output.put11(TYPE_ARGUMENT, typeArg);
} else {
throw new IllegalArgumentException();
}
}
output.data[0] = (byte) (output.length / 2);
return new TypePath(output.data, 0);
}
/**
* Returns a string representation of this type path. {@link #ARRAY_ELEMENT} steps are represented
* with '[', {@link #INNER_TYPE} steps with '.', {@link #WILDCARD_BOUND} steps with '*' and {@link
* #TYPE_ARGUMENT} steps with their type argument index in decimal form followed by ';'.
*/
@Override
public String toString() {
int length = getLength();
StringBuilder result = new StringBuilder(length * 2);
for (int i = 0; i < length; ++i) {
switch (getStep(i)) {
case ARRAY_ELEMENT:
result.append('[');
break;
case INNER_TYPE:
result.append('.');
break;
case WILDCARD_BOUND:
result.append('*');
break;
case TYPE_ARGUMENT:
result.append(getStepArgument(i)).append(';');
break;
default:
throw new AssertionError();
}
}
return result.toString();
}
/**
* Puts the type_path JVMS structure corresponding to the given TypePath into the given
* ByteVector.
*
* @param typePath a TypePath instance, or {@literal null} for empty paths.
* @param output where the type path must be put.
*/
static void put(final TypePath typePath, final ByteVector output) {
if (typePath == null) {
output.putByte(0);
} else {
int length = typePath.typePathContainer[typePath.typePathOffset] * 2 + 1;
output.putByteArray(typePath.typePathContainer, typePath.typePathOffset, length);
}
}
}
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