org.objectweb.asm.ClassReader Maven / Gradle / Ivy
/***
* 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;
import java.io.IOException;
import java.io.InputStream;
/**
* A Java class parser to make a {@link ClassVisitor} visit an existing class.
* This class parses a byte array conforming to the Java class file format and
* calls the appropriate visit methods of a given class visitor for each field,
* method and bytecode instruction encountered.
*
* @author Eric Bruneton
* @author Eugene Kuleshov
*/
public class ClassReader {
/**
* True to enable signatures support.
*/
static final boolean SIGNATURES = true;
/**
* True to enable annotations support.
*/
static final boolean ANNOTATIONS = true;
/**
* True to enable stack map frames support.
*/
static final boolean FRAMES = true;
/**
* True to enable bytecode writing support.
*/
static final boolean WRITER = true;
/**
* True to enable JSR_W and GOTO_W support.
*/
static final boolean RESIZE = true;
/**
* Flag to skip method code. If this class is set CODE
* attribute won't be visited. This can be used, for example, to retrieve
* annotations for methods and method parameters.
*/
public static final int SKIP_CODE = 1;
/**
* Flag to skip the debug information in the class. If this flag is set the
* debug information of the class is not visited, i.e. the
* {@link MethodVisitor#visitLocalVariable visitLocalVariable} and
* {@link MethodVisitor#visitLineNumber visitLineNumber} methods will not be
* called.
*/
public static final int SKIP_DEBUG = 2;
/**
* Flag to skip the stack map frames in the class. If this flag is set the
* stack map frames of the class is not visited, i.e. the
* {@link MethodVisitor#visitFrame visitFrame} method will not be called.
* This flag is useful when the {@link ClassWriter#COMPUTE_FRAMES} option is
* used: it avoids visiting frames that will be ignored and recomputed from
* scratch in the class writer.
*/
public static final int SKIP_FRAMES = 4;
/**
* Flag to expand the stack map frames. By default stack map frames are
* visited in their original format (i.e. "expanded" for classes whose
* version is less than V1_6, and "compressed" for the other classes). If
* this flag is set, stack map frames are always visited in expanded format
* (this option adds a decompression/recompression step in ClassReader and
* ClassWriter which degrades performances quite a lot).
*/
public static final int EXPAND_FRAMES = 8;
/**
* The class to be parsed. The content of this array must not be
* modified. This field is intended for {@link Attribute} sub classes, and
* is normally not needed by class generators or adapters.
*/
public final byte[] b;
/**
* The start index of each constant pool item in {@link #b b}, plus one. The
* one byte offset skips the constant pool item tag that indicates its type.
*/
private final int[] items;
/**
* The String objects corresponding to the CONSTANT_Utf8 items. This cache
* avoids multiple parsing of a given CONSTANT_Utf8 constant pool item,
* which GREATLY improves performances (by a factor 2 to 3). This caching
* strategy could be extended to all constant pool items, but its benefit
* would not be so great for these items (because they are much less
* expensive to parse than CONSTANT_Utf8 items).
*/
private final String[] strings;
/**
* Maximum length of the strings contained in the constant pool of the
* class.
*/
private final int maxStringLength;
/**
* Start index of the class header information (access, name...) in
* {@link #b b}.
*/
public final int header;
// ------------------------------------------------------------------------
// Constructors
// ------------------------------------------------------------------------
/**
* Constructs a new {@link ClassReader} object.
*
* @param b
* the bytecode of the class to be read.
*/
public ClassReader(final byte[] b) {
this(b, 0, b.length);
}
/**
* Constructs a new {@link ClassReader} object.
*
* @param b
* the bytecode of the class to be read.
* @param off
* the start offset of the class data.
* @param len
* the length of the class data.
*/
public ClassReader(final byte[] b, final int off, final int len) {
this.b = b;
// checks the class version
if (readShort(off + 6) > Opcodes.V1_8) {
throw new IllegalArgumentException();
}
// parses the constant pool
items = new int[readUnsignedShort(off + 8)];
int n = items.length;
strings = new String[n];
int max = 0;
int index = off + 10;
for (int i = 1; i < n; ++i) {
items[i] = index + 1;
int size;
switch (b[index]) {
case ClassWriter.FIELD:
case ClassWriter.METH:
case ClassWriter.IMETH:
case ClassWriter.INT:
case ClassWriter.FLOAT:
case ClassWriter.NAME_TYPE:
case ClassWriter.INDY:
size = 5;
break;
case ClassWriter.LONG:
case ClassWriter.DOUBLE:
size = 9;
++i;
break;
case ClassWriter.UTF8:
size = 3 + readUnsignedShort(index + 1);
if (size > max) {
max = size;
}
break;
case ClassWriter.HANDLE:
size = 4;
break;
// case ClassWriter.CLASS:
// case ClassWriter.STR:
// case ClassWriter.MTYPE
default:
size = 3;
break;
}
index += size;
}
maxStringLength = max;
// the class header information starts just after the constant pool
header = index;
}
/**
* Returns the class's access flags (see {@link Opcodes}). This value may
* not reflect Deprecated and Synthetic flags when bytecode is before 1.5
* and those flags are represented by attributes.
*
* @return the class access flags
*
* @see ClassVisitor#visit(int, int, String, String, String, String[])
*/
public int getAccess() {
return readUnsignedShort(header);
}
/**
* Returns the internal name of the class (see
* {@link Type#getInternalName() getInternalName}).
*
* @return the internal class name
*
* @see ClassVisitor#visit(int, int, String, String, String, String[])
*/
public String getClassName() {
return readClass(header + 2, new char[maxStringLength]);
}
/**
* Returns the internal of name of the super class (see
* {@link Type#getInternalName() getInternalName}). For interfaces, the
* super class is {@link Object}.
*
* @return the internal name of super class, or null for
* {@link Object} class.
*
* @see ClassVisitor#visit(int, int, String, String, String, String[])
*/
public String getSuperName() {
return readClass(header + 4, new char[maxStringLength]);
}
/**
* Returns the internal names of the class's interfaces (see
* {@link Type#getInternalName() getInternalName}).
*
* @return the array of internal names for all implemented interfaces or
* null.
*
* @see ClassVisitor#visit(int, int, String, String, String, String[])
*/
public String[] getInterfaces() {
int index = header + 6;
int n = readUnsignedShort(index);
String[] interfaces = new String[n];
if (n > 0) {
char[] buf = new char[maxStringLength];
for (int i = 0; i < n; ++i) {
index += 2;
interfaces[i] = readClass(index, buf);
}
}
return interfaces;
}
/**
* Copies the constant pool data into the given {@link ClassWriter}. Should
* be called before the {@link #accept(ClassVisitor,int)} method.
*
* @param classWriter
* the {@link ClassWriter} to copy constant pool into.
*/
void copyPool(final ClassWriter classWriter) {
char[] buf = new char[maxStringLength];
int ll = items.length;
Item[] items2 = new Item[ll];
for (int i = 1; i < ll; i++) {
int index = items[i];
int tag = b[index - 1];
Item item = new Item(i);
int nameType;
switch (tag) {
case ClassWriter.FIELD:
case ClassWriter.METH:
case ClassWriter.IMETH:
nameType = items[readUnsignedShort(index + 2)];
item.set(tag, readClass(index, buf), readUTF8(nameType, buf),
readUTF8(nameType + 2, buf));
break;
case ClassWriter.INT:
item.set(readInt(index));
break;
case ClassWriter.FLOAT:
item.set(Float.intBitsToFloat(readInt(index)));
break;
case ClassWriter.NAME_TYPE:
item.set(tag, readUTF8(index, buf), readUTF8(index + 2, buf),
null);
break;
case ClassWriter.LONG:
item.set(readLong(index));
++i;
break;
case ClassWriter.DOUBLE:
item.set(Double.longBitsToDouble(readLong(index)));
++i;
break;
case ClassWriter.UTF8: {
String s = strings[i];
if (s == null) {
index = items[i];
s = strings[i] = readUTF(index + 2,
readUnsignedShort(index), buf);
}
item.set(tag, s, null, null);
break;
}
case ClassWriter.HANDLE: {
int fieldOrMethodRef = items[readUnsignedShort(index + 1)];
nameType = items[readUnsignedShort(fieldOrMethodRef + 2)];
item.set(ClassWriter.HANDLE_BASE + readByte(index),
readClass(fieldOrMethodRef, buf),
readUTF8(nameType, buf), readUTF8(nameType + 2, buf));
break;
}
case ClassWriter.INDY:
if (classWriter.bootstrapMethods == null) {
copyBootstrapMethods(classWriter, items2, buf);
}
nameType = items[readUnsignedShort(index + 2)];
item.set(readUTF8(nameType, buf), readUTF8(nameType + 2, buf),
readUnsignedShort(index));
break;
// case ClassWriter.STR:
// case ClassWriter.CLASS:
// case ClassWriter.MTYPE
default:
item.set(tag, readUTF8(index, buf), null, null);
break;
}
int index2 = item.hashCode % items2.length;
item.next = items2[index2];
items2[index2] = item;
}
int off = items[1] - 1;
classWriter.pool.putByteArray(b, off, header - off);
classWriter.items = items2;
classWriter.threshold = (int) (0.75d * ll);
classWriter.index = ll;
}
/**
* Copies the bootstrap method data into the given {@link ClassWriter}.
* Should be called before the {@link #accept(ClassVisitor,int)} method.
*
* @param classWriter
* the {@link ClassWriter} to copy bootstrap methods into.
*/
private void copyBootstrapMethods(final ClassWriter classWriter,
final Item[] items, final char[] c) {
// finds the "BootstrapMethods" attribute
int u = getAttributes();
boolean found = false;
for (int i = readUnsignedShort(u); i > 0; --i) {
String attrName = readUTF8(u + 2, c);
if ("BootstrapMethods".equals(attrName)) {
found = true;
break;
}
u += 6 + readInt(u + 4);
}
if (!found) {
return;
}
// copies the bootstrap methods in the class writer
int boostrapMethodCount = readUnsignedShort(u + 8);
for (int j = 0, v = u + 10; j < boostrapMethodCount; j++) {
int position = v - u - 10;
int hashCode = readConst(readUnsignedShort(v), c).hashCode();
for (int k = readUnsignedShort(v + 2); k > 0; --k) {
hashCode ^= readConst(readUnsignedShort(v + 4), c).hashCode();
v += 2;
}
v += 4;
Item item = new Item(j);
item.set(position, hashCode & 0x7FFFFFFF);
int index = item.hashCode % items.length;
item.next = items[index];
items[index] = item;
}
int attrSize = readInt(u + 4);
ByteVector bootstrapMethods = new ByteVector(attrSize + 62);
bootstrapMethods.putByteArray(b, u + 10, attrSize - 2);
classWriter.bootstrapMethodsCount = boostrapMethodCount;
classWriter.bootstrapMethods = bootstrapMethods;
}
/**
* Constructs a new {@link ClassReader} object.
*
* @param is
* an input stream from which to read the class.
* @throws IOException
* if a problem occurs during reading.
*/
public ClassReader(final InputStream is) throws IOException {
this(readClass(is, false));
}
/**
* Constructs a new {@link ClassReader} object.
*
* @param name
* the binary qualified name of the class to be read.
* @throws IOException
* if an exception occurs during reading.
*/
public ClassReader(final String name) throws IOException {
this(readClass(
ClassLoader.getSystemResourceAsStream(name.replace('.', '/')
+ ".class"), true));
}
/**
* Reads the bytecode of a class.
*
* @param is
* an input stream from which to read the class.
* @param close
* true to close the input stream after reading.
* @return the bytecode read from the given input stream.
* @throws IOException
* if a problem occurs during reading.
*/
private static byte[] readClass(final InputStream is, boolean close)
throws IOException {
if (is == null) {
throw new IOException("Class not found");
}
try {
byte[] b = new byte[is.available()];
int len = 0;
while (true) {
int n = is.read(b, len, b.length - len);
if (n == -1) {
if (len < b.length) {
byte[] c = new byte[len];
System.arraycopy(b, 0, c, 0, len);
b = c;
}
return b;
}
len += n;
if (len == b.length) {
int last = is.read();
if (last < 0) {
return b;
}
byte[] c = new byte[b.length + 1000];
System.arraycopy(b, 0, c, 0, len);
c[len++] = (byte) last;
b = c;
}
}
} finally {
if (close) {
is.close();
}
}
}
// ------------------------------------------------------------------------
// Public methods
// ------------------------------------------------------------------------
/**
* Makes the given visitor visit the Java class of this {@link ClassReader}
* . This class is the one specified in the constructor (see
* {@link #ClassReader(byte[]) ClassReader}).
*
* @param classVisitor
* the visitor that must visit this class.
* @param flags
* option flags that can be used to modify the default behavior
* of this class. See {@link #SKIP_DEBUG}, {@link #EXPAND_FRAMES}
* , {@link #SKIP_FRAMES}, {@link #SKIP_CODE}.
*/
public void accept(final ClassVisitor classVisitor, final int flags) {
accept(classVisitor, new Attribute[0], flags);
}
/**
* Makes the given visitor visit the Java class of this {@link ClassReader}.
* This class is the one specified in the constructor (see
* {@link #ClassReader(byte[]) ClassReader}).
*
* @param classVisitor
* the visitor that must visit this class.
* @param attrs
* prototypes of the attributes that must be parsed during the
* visit of the class. Any attribute whose type is not equal to
* the type of one the prototypes will not be parsed: its byte
* array value will be passed unchanged to the ClassWriter.
* This may corrupt it if this value contains references to
* the constant pool, or has syntactic or semantic links with a
* class element that has been transformed by a class adapter
* between the reader and the writer.
* @param flags
* option flags that can be used to modify the default behavior
* of this class. See {@link #SKIP_DEBUG}, {@link #EXPAND_FRAMES}
* , {@link #SKIP_FRAMES}, {@link #SKIP_CODE}.
*/
public void accept(final ClassVisitor classVisitor,
final Attribute[] attrs, final int flags) {
int u = header; // current offset in the class file
char[] c = new char[maxStringLength]; // buffer used to read strings
Context context = new Context();
context.attrs = attrs;
context.flags = flags;
context.buffer = c;
// reads the class declaration
int access = readUnsignedShort(u);
String name = readClass(u + 2, c);
String superClass = readClass(u + 4, c);
String[] interfaces = new String[readUnsignedShort(u + 6)];
u += 8;
for (int i = 0; i < interfaces.length; ++i) {
interfaces[i] = readClass(u, c);
u += 2;
}
// reads the class attributes
String signature = null;
String sourceFile = null;
String sourceDebug = null;
String enclosingOwner = null;
String enclosingName = null;
String enclosingDesc = null;
int anns = 0;
int ianns = 0;
int tanns = 0;
int itanns = 0;
int innerClasses = 0;
Attribute attributes = null;
u = getAttributes();
for (int i = readUnsignedShort(u); i > 0; --i) {
String attrName = readUTF8(u + 2, c);
// tests are sorted in decreasing frequency order
// (based on frequencies observed on typical classes)
if ("SourceFile".equals(attrName)) {
sourceFile = readUTF8(u + 8, c);
} else if ("InnerClasses".equals(attrName)) {
innerClasses = u + 8;
} else if ("EnclosingMethod".equals(attrName)) {
enclosingOwner = readClass(u + 8, c);
int item = readUnsignedShort(u + 10);
if (item != 0) {
enclosingName = readUTF8(items[item], c);
enclosingDesc = readUTF8(items[item] + 2, c);
}
} else if (SIGNATURES && "Signature".equals(attrName)) {
signature = readUTF8(u + 8, c);
} else if (ANNOTATIONS
&& "RuntimeVisibleAnnotations".equals(attrName)) {
anns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeVisibleTypeAnnotations".equals(attrName)) {
tanns = u + 8;
} else if ("Deprecated".equals(attrName)) {
access |= Opcodes.ACC_DEPRECATED;
} else if ("Synthetic".equals(attrName)) {
access |= Opcodes.ACC_SYNTHETIC
| ClassWriter.ACC_SYNTHETIC_ATTRIBUTE;
} else if ("SourceDebugExtension".equals(attrName)) {
int len = readInt(u + 4);
sourceDebug = readUTF(u + 8, len, new char[len]);
} else if (ANNOTATIONS
&& "RuntimeInvisibleAnnotations".equals(attrName)) {
ianns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeInvisibleTypeAnnotations".equals(attrName)) {
itanns = u + 8;
} else if ("BootstrapMethods".equals(attrName)) {
int[] bootstrapMethods = new int[readUnsignedShort(u + 8)];
for (int j = 0, v = u + 10; j < bootstrapMethods.length; j++) {
bootstrapMethods[j] = v;
v += 2 + readUnsignedShort(v + 2) << 1;
}
context.bootstrapMethods = bootstrapMethods;
} else {
Attribute attr = readAttribute(attrs, attrName, u + 8,
readInt(u + 4), c, -1, null);
if (attr != null) {
attr.next = attributes;
attributes = attr;
}
}
u += 6 + readInt(u + 4);
}
// visits the class declaration
classVisitor.visit(readInt(items[1] - 7), access, name, signature,
superClass, interfaces);
// visits the source and debug info
if ((flags & SKIP_DEBUG) == 0
&& (sourceFile != null || sourceDebug != null)) {
classVisitor.visitSource(sourceFile, sourceDebug);
}
// visits the outer class
if (enclosingOwner != null) {
classVisitor.visitOuterClass(enclosingOwner, enclosingName,
enclosingDesc);
}
// visits the class annotations and type annotations
if (ANNOTATIONS && anns != 0) {
for (int i = readUnsignedShort(anns), v = anns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
classVisitor.visitAnnotation(readUTF8(v, c), true));
}
}
if (ANNOTATIONS && ianns != 0) {
for (int i = readUnsignedShort(ianns), v = ianns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
classVisitor.visitAnnotation(readUTF8(v, c), false));
}
}
if (ANNOTATIONS && tanns != 0) {
for (int i = readUnsignedShort(tanns), v = tanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
classVisitor.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), true));
}
}
if (ANNOTATIONS && itanns != 0) {
for (int i = readUnsignedShort(itanns), v = itanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
classVisitor.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), false));
}
}
// visits the attributes
while (attributes != null) {
Attribute attr = attributes.next;
attributes.next = null;
classVisitor.visitAttribute(attributes);
attributes = attr;
}
// visits the inner classes
if (innerClasses != 0) {
int v = innerClasses + 2;
for (int i = readUnsignedShort(innerClasses); i > 0; --i) {
classVisitor.visitInnerClass(readClass(v, c),
readClass(v + 2, c), readUTF8(v + 4, c),
readUnsignedShort(v + 6));
v += 8;
}
}
// visits the fields and methods
u = header + 10 + 2 * interfaces.length;
for (int i = readUnsignedShort(u - 2); i > 0; --i) {
u = readField(classVisitor, context, u);
}
u += 2;
for (int i = readUnsignedShort(u - 2); i > 0; --i) {
u = readMethod(classVisitor, context, u);
}
// visits the end of the class
classVisitor.visitEnd();
}
/**
* Reads a field and makes the given visitor visit it.
*
* @param classVisitor
* the visitor that must visit the field.
* @param context
* information about the class being parsed.
* @param u
* the start offset of the field in the class file.
* @return the offset of the first byte following the field in the class.
*/
private int readField(final ClassVisitor classVisitor,
final Context context, int u) {
// reads the field declaration
char[] c = context.buffer;
int access = readUnsignedShort(u);
String name = readUTF8(u + 2, c);
String desc = readUTF8(u + 4, c);
u += 6;
// reads the field attributes
String signature = null;
int anns = 0;
int ianns = 0;
int tanns = 0;
int itanns = 0;
Object value = null;
Attribute attributes = null;
for (int i = readUnsignedShort(u); i > 0; --i) {
String attrName = readUTF8(u + 2, c);
// tests are sorted in decreasing frequency order
// (based on frequencies observed on typical classes)
if ("ConstantValue".equals(attrName)) {
int item = readUnsignedShort(u + 8);
value = item == 0 ? null : readConst(item, c);
} else if (SIGNATURES && "Signature".equals(attrName)) {
signature = readUTF8(u + 8, c);
} else if ("Deprecated".equals(attrName)) {
access |= Opcodes.ACC_DEPRECATED;
} else if ("Synthetic".equals(attrName)) {
access |= Opcodes.ACC_SYNTHETIC
| ClassWriter.ACC_SYNTHETIC_ATTRIBUTE;
} else if (ANNOTATIONS
&& "RuntimeVisibleAnnotations".equals(attrName)) {
anns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeVisibleTypeAnnotations".equals(attrName)) {
tanns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeInvisibleAnnotations".equals(attrName)) {
ianns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeInvisibleTypeAnnotations".equals(attrName)) {
itanns = u + 8;
} else {
Attribute attr = readAttribute(context.attrs, attrName, u + 8,
readInt(u + 4), c, -1, null);
if (attr != null) {
attr.next = attributes;
attributes = attr;
}
}
u += 6 + readInt(u + 4);
}
u += 2;
// visits the field declaration
FieldVisitor fv = classVisitor.visitField(access, name, desc,
signature, value);
if (fv == null) {
return u;
}
// visits the field annotations and type annotations
if (ANNOTATIONS && anns != 0) {
for (int i = readUnsignedShort(anns), v = anns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
fv.visitAnnotation(readUTF8(v, c), true));
}
}
if (ANNOTATIONS && ianns != 0) {
for (int i = readUnsignedShort(ianns), v = ianns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
fv.visitAnnotation(readUTF8(v, c), false));
}
}
if (ANNOTATIONS && tanns != 0) {
for (int i = readUnsignedShort(tanns), v = tanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
fv.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), true));
}
}
if (ANNOTATIONS && itanns != 0) {
for (int i = readUnsignedShort(itanns), v = itanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
fv.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), false));
}
}
// visits the field attributes
while (attributes != null) {
Attribute attr = attributes.next;
attributes.next = null;
fv.visitAttribute(attributes);
attributes = attr;
}
// visits the end of the field
fv.visitEnd();
return u;
}
/**
* Reads a method and makes the given visitor visit it.
*
* @param classVisitor
* the visitor that must visit the method.
* @param context
* information about the class being parsed.
* @param u
* the start offset of the method in the class file.
* @return the offset of the first byte following the method in the class.
*/
private int readMethod(final ClassVisitor classVisitor,
final Context context, int u) {
// reads the method declaration
char[] c = context.buffer;
context.access = readUnsignedShort(u);
context.name = readUTF8(u + 2, c);
context.desc = readUTF8(u + 4, c);
u += 6;
// reads the method attributes
int code = 0;
int exception = 0;
String[] exceptions = null;
String signature = null;
int methodParameters = 0;
int anns = 0;
int ianns = 0;
int tanns = 0;
int itanns = 0;
int dann = 0;
int mpanns = 0;
int impanns = 0;
int firstAttribute = u;
Attribute attributes = null;
for (int i = readUnsignedShort(u); i > 0; --i) {
String attrName = readUTF8(u + 2, c);
// tests are sorted in decreasing frequency order
// (based on frequencies observed on typical classes)
if ("Code".equals(attrName)) {
if ((context.flags & SKIP_CODE) == 0) {
code = u + 8;
}
} else if ("Exceptions".equals(attrName)) {
exceptions = new String[readUnsignedShort(u + 8)];
exception = u + 10;
for (int j = 0; j < exceptions.length; ++j) {
exceptions[j] = readClass(exception, c);
exception += 2;
}
} else if (SIGNATURES && "Signature".equals(attrName)) {
signature = readUTF8(u + 8, c);
} else if ("Deprecated".equals(attrName)) {
context.access |= Opcodes.ACC_DEPRECATED;
} else if (ANNOTATIONS
&& "RuntimeVisibleAnnotations".equals(attrName)) {
anns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeVisibleTypeAnnotations".equals(attrName)) {
tanns = u + 8;
} else if (ANNOTATIONS && "AnnotationDefault".equals(attrName)) {
dann = u + 8;
} else if ("Synthetic".equals(attrName)) {
context.access |= Opcodes.ACC_SYNTHETIC
| ClassWriter.ACC_SYNTHETIC_ATTRIBUTE;
} else if (ANNOTATIONS
&& "RuntimeInvisibleAnnotations".equals(attrName)) {
ianns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeInvisibleTypeAnnotations".equals(attrName)) {
itanns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeVisibleParameterAnnotations".equals(attrName)) {
mpanns = u + 8;
} else if (ANNOTATIONS
&& "RuntimeInvisibleParameterAnnotations".equals(attrName)) {
impanns = u + 8;
} else if ("MethodParameters".equals(attrName)) {
methodParameters = u + 8;
} else {
Attribute attr = readAttribute(context.attrs, attrName, u + 8,
readInt(u + 4), c, -1, null);
if (attr != null) {
attr.next = attributes;
attributes = attr;
}
}
u += 6 + readInt(u + 4);
}
u += 2;
// visits the method declaration
MethodVisitor mv = classVisitor.visitMethod(context.access,
context.name, context.desc, signature, exceptions);
if (mv == null) {
return u;
}
/*
* if the returned MethodVisitor is in fact a MethodWriter, it means
* there is no method adapter between the reader and the writer. If, in
* addition, the writer's constant pool was copied from this reader
* (mw.cw.cr == this), and the signature and exceptions of the method
* have not been changed, then it is possible to skip all visit events
* and just copy the original code of the method to the writer (the
* access, name and descriptor can have been changed, this is not
* important since they are not copied as is from the reader).
*/
if (WRITER && mv instanceof MethodWriter) {
MethodWriter mw = (MethodWriter) mv;
if (mw.cw.cr == this && signature == mw.signature) {
boolean sameExceptions = false;
if (exceptions == null) {
sameExceptions = mw.exceptionCount == 0;
} else if (exceptions.length == mw.exceptionCount) {
sameExceptions = true;
for (int j = exceptions.length - 1; j >= 0; --j) {
exception -= 2;
if (mw.exceptions[j] != readUnsignedShort(exception)) {
sameExceptions = false;
break;
}
}
}
if (sameExceptions) {
/*
* we do not copy directly the code into MethodWriter to
* save a byte array copy operation. The real copy will be
* done in ClassWriter.toByteArray().
*/
mw.classReaderOffset = firstAttribute;
mw.classReaderLength = u - firstAttribute;
return u;
}
}
}
// visit the method parameters
if (methodParameters != 0) {
for (int i = b[methodParameters] & 0xFF, v = methodParameters + 1; i > 0; --i, v = v + 4) {
mv.visitParameter(readUTF8(v, c), readUnsignedShort(v + 2));
}
}
// visits the method annotations
if (ANNOTATIONS && dann != 0) {
AnnotationVisitor dv = mv.visitAnnotationDefault();
readAnnotationValue(dann, c, null, dv);
if (dv != null) {
dv.visitEnd();
}
}
if (ANNOTATIONS && anns != 0) {
for (int i = readUnsignedShort(anns), v = anns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
mv.visitAnnotation(readUTF8(v, c), true));
}
}
if (ANNOTATIONS && ianns != 0) {
for (int i = readUnsignedShort(ianns), v = ianns + 2; i > 0; --i) {
v = readAnnotationValues(v + 2, c, true,
mv.visitAnnotation(readUTF8(v, c), false));
}
}
if (ANNOTATIONS && tanns != 0) {
for (int i = readUnsignedShort(tanns), v = tanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
mv.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), true));
}
}
if (ANNOTATIONS && itanns != 0) {
for (int i = readUnsignedShort(itanns), v = itanns + 2; i > 0; --i) {
v = readAnnotationTarget(context, v);
v = readAnnotationValues(v + 2, c, true,
mv.visitTypeAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), false));
}
}
if (ANNOTATIONS && mpanns != 0) {
readParameterAnnotations(mv, context, mpanns, true);
}
if (ANNOTATIONS && impanns != 0) {
readParameterAnnotations(mv, context, impanns, false);
}
// visits the method attributes
while (attributes != null) {
Attribute attr = attributes.next;
attributes.next = null;
mv.visitAttribute(attributes);
attributes = attr;
}
// visits the method code
if (code != 0) {
mv.visitCode();
readCode(mv, context, code);
}
// visits the end of the method
mv.visitEnd();
return u;
}
/**
* Reads the bytecode of a method and makes the given visitor visit it.
*
* @param mv
* the visitor that must visit the method's code.
* @param context
* information about the class being parsed.
* @param u
* the start offset of the code attribute in the class file.
*/
private void readCode(final MethodVisitor mv, final Context context, int u) {
// reads the header
byte[] b = this.b;
char[] c = context.buffer;
int maxStack = readUnsignedShort(u);
int maxLocals = readUnsignedShort(u + 2);
int codeLength = readInt(u + 4);
u += 8;
// reads the bytecode to find the labels
int codeStart = u;
int codeEnd = u + codeLength;
Label[] labels = context.labels = new Label[codeLength + 2];
readLabel(codeLength + 1, labels);
while (u < codeEnd) {
int offset = u - codeStart;
int opcode = b[u] & 0xFF;
switch (ClassWriter.TYPE[opcode]) {
case ClassWriter.NOARG_INSN:
case ClassWriter.IMPLVAR_INSN:
u += 1;
break;
case ClassWriter.LABEL_INSN:
readLabel(offset + readShort(u + 1), labels);
u += 3;
break;
case ClassWriter.LABELW_INSN:
readLabel(offset + readInt(u + 1), labels);
u += 5;
break;
case ClassWriter.WIDE_INSN:
opcode = b[u + 1] & 0xFF;
if (opcode == Opcodes.IINC) {
u += 6;
} else {
u += 4;
}
break;
case ClassWriter.TABL_INSN:
// skips 0 to 3 padding bytes
u = u + 4 - (offset & 3);
// reads instruction
readLabel(offset + readInt(u), labels);
for (int i = readInt(u + 8) - readInt(u + 4) + 1; i > 0; --i) {
readLabel(offset + readInt(u + 12), labels);
u += 4;
}
u += 12;
break;
case ClassWriter.LOOK_INSN:
// skips 0 to 3 padding bytes
u = u + 4 - (offset & 3);
// reads instruction
readLabel(offset + readInt(u), labels);
for (int i = readInt(u + 4); i > 0; --i) {
readLabel(offset + readInt(u + 12), labels);
u += 8;
}
u += 8;
break;
case ClassWriter.VAR_INSN:
case ClassWriter.SBYTE_INSN:
case ClassWriter.LDC_INSN:
u += 2;
break;
case ClassWriter.SHORT_INSN:
case ClassWriter.LDCW_INSN:
case ClassWriter.FIELDORMETH_INSN:
case ClassWriter.TYPE_INSN:
case ClassWriter.IINC_INSN:
u += 3;
break;
case ClassWriter.ITFMETH_INSN:
case ClassWriter.INDYMETH_INSN:
u += 5;
break;
// case MANA_INSN:
default:
u += 4;
break;
}
}
// reads the try catch entries to find the labels, and also visits them
for (int i = readUnsignedShort(u); i > 0; --i) {
Label start = readLabel(readUnsignedShort(u + 2), labels);
Label end = readLabel(readUnsignedShort(u + 4), labels);
Label handler = readLabel(readUnsignedShort(u + 6), labels);
String type = readUTF8(items[readUnsignedShort(u + 8)], c);
mv.visitTryCatchBlock(start, end, handler, type);
u += 8;
}
u += 2;
// reads the code attributes
int[] tanns = null; // start index of each visible type annotation
int[] itanns = null; // start index of each invisible type annotation
int tann = 0; // current index in tanns array
int itann = 0; // current index in itanns array
int ntoff = -1; // next visible type annotation code offset
int nitoff = -1; // next invisible type annotation code offset
int varTable = 0;
int varTypeTable = 0;
boolean zip = true;
boolean unzip = (context.flags & EXPAND_FRAMES) != 0;
int stackMap = 0;
int stackMapSize = 0;
int frameCount = 0;
Context frame = null;
Attribute attributes = null;
for (int i = readUnsignedShort(u); i > 0; --i) {
String attrName = readUTF8(u + 2, c);
if ("LocalVariableTable".equals(attrName)) {
if ((context.flags & SKIP_DEBUG) == 0) {
varTable = u + 8;
for (int j = readUnsignedShort(u + 8), v = u; j > 0; --j) {
int label = readUnsignedShort(v + 10);
if (labels[label] == null) {
readLabel(label, labels).status |= Label.DEBUG;
}
label += readUnsignedShort(v + 12);
if (labels[label] == null) {
readLabel(label, labels).status |= Label.DEBUG;
}
v += 10;
}
}
} else if ("LocalVariableTypeTable".equals(attrName)) {
varTypeTable = u + 8;
} else if ("LineNumberTable".equals(attrName)) {
if ((context.flags & SKIP_DEBUG) == 0) {
for (int j = readUnsignedShort(u + 8), v = u; j > 0; --j) {
int label = readUnsignedShort(v + 10);
if (labels[label] == null) {
readLabel(label, labels).status |= Label.DEBUG;
}
Label l = labels[label];
while (l.line > 0) {
if (l.next == null) {
l.next = new Label();
}
l = l.next;
}
l.line = readUnsignedShort(v + 12);
v += 4;
}
}
} else if (ANNOTATIONS
&& "RuntimeVisibleTypeAnnotations".equals(attrName)) {
tanns = readTypeAnnotations(mv, context, u + 8, true);
ntoff = tanns.length == 0 || readByte(tanns[0]) < 0x43 ? -1
: readUnsignedShort(tanns[0] + 1);
} else if (ANNOTATIONS
&& "RuntimeInvisibleTypeAnnotations".equals(attrName)) {
itanns = readTypeAnnotations(mv, context, u + 8, false);
nitoff = itanns.length == 0 || readByte(itanns[0]) < 0x43 ? -1
: readUnsignedShort(itanns[0] + 1);
} else if (FRAMES && "StackMapTable".equals(attrName)) {
if ((context.flags & SKIP_FRAMES) == 0) {
stackMap = u + 10;
stackMapSize = readInt(u + 4);
frameCount = readUnsignedShort(u + 8);
}
/*
* here we do not extract the labels corresponding to the
* attribute content. This would require a full parsing of the
* attribute, which would need to be repeated in the second
* phase (see below). Instead the content of the attribute is
* read one frame at a time (i.e. after a frame has been
* visited, the next frame is read), and the labels it contains
* are also extracted one frame at a time. Thanks to the
* ordering of frames, having only a "one frame lookahead" is
* not a problem, i.e. it is not possible to see an offset
* smaller than the offset of the current insn and for which no
* Label exist.
*/
/*
* This is not true for UNINITIALIZED type offsets. We solve
* this by parsing the stack map table without a full decoding
* (see below).
*/
} else if (FRAMES && "StackMap".equals(attrName)) {
if ((context.flags & SKIP_FRAMES) == 0) {
zip = false;
stackMap = u + 10;
stackMapSize = readInt(u + 4);
frameCount = readUnsignedShort(u + 8);
}
/*
* IMPORTANT! here we assume that the frames are ordered, as in
* the StackMapTable attribute, although this is not guaranteed
* by the attribute format.
*/
} else {
for (int j = 0; j < context.attrs.length; ++j) {
if (context.attrs[j].type.equals(attrName)) {
Attribute attr = context.attrs[j].read(this, u + 8,
readInt(u + 4), c, codeStart - 8, labels);
if (attr != null) {
attr.next = attributes;
attributes = attr;
}
}
}
}
u += 6 + readInt(u + 4);
}
u += 2;
// generates the first (implicit) stack map frame
if (FRAMES && stackMap != 0) {
/*
* for the first explicit frame the offset is not offset_delta + 1
* but only offset_delta; setting the implicit frame offset to -1
* allow the use of the "offset_delta + 1" rule in all cases
*/
frame = context;
frame.offset = -1;
frame.mode = 0;
frame.localCount = 0;
frame.localDiff = 0;
frame.stackCount = 0;
frame.local = new Object[maxLocals];
frame.stack = new Object[maxStack];
if (unzip) {
getImplicitFrame(context);
}
/*
* Finds labels for UNINITIALIZED frame types. Instead of decoding
* each element of the stack map table, we look for 3 consecutive
* bytes that "look like" an UNINITIALIZED type (tag 8, offset
* within code bounds, NEW instruction at this offset). We may find
* false positives (i.e. not real UNINITIALIZED types), but this
* should be rare, and the only consequence will be the creation of
* an unneeded label. This is better than creating a label for each
* NEW instruction, and faster than fully decoding the whole stack
* map table.
*/
for (int i = stackMap; i < stackMap + stackMapSize - 2; ++i) {
if (b[i] == 8) { // UNINITIALIZED FRAME TYPE
int v = readUnsignedShort(i + 1);
if (v >= 0 && v < codeLength) {
if ((b[codeStart + v] & 0xFF) == Opcodes.NEW) {
readLabel(v, labels);
}
}
}
}
}
// visits the instructions
u = codeStart;
while (u < codeEnd) {
int offset = u - codeStart;
// visits the label and line number for this offset, if any
Label l = labels[offset];
if (l != null) {
Label next = l.next;
l.next = null;
mv.visitLabel(l);
if ((context.flags & SKIP_DEBUG) == 0 && l.line > 0) {
mv.visitLineNumber(l.line, l);
while (next != null) {
mv.visitLineNumber(next.line, l);
next = next.next;
}
}
}
// visits the frame for this offset, if any
while (FRAMES && frame != null
&& (frame.offset == offset || frame.offset == -1)) {
// if there is a frame for this offset, makes the visitor visit
// it, and reads the next frame if there is one.
if (frame.offset != -1) {
if (!zip || unzip) {
mv.visitFrame(Opcodes.F_NEW, frame.localCount,
frame.local, frame.stackCount, frame.stack);
} else {
mv.visitFrame(frame.mode, frame.localDiff, frame.local,
frame.stackCount, frame.stack);
}
}
if (frameCount > 0) {
stackMap = readFrame(stackMap, zip, unzip, frame);
--frameCount;
} else {
frame = null;
}
}
// visits the instruction at this offset
int opcode = b[u] & 0xFF;
switch (ClassWriter.TYPE[opcode]) {
case ClassWriter.NOARG_INSN:
mv.visitInsn(opcode);
u += 1;
break;
case ClassWriter.IMPLVAR_INSN:
if (opcode > Opcodes.ISTORE) {
opcode -= 59; // ISTORE_0
mv.visitVarInsn(Opcodes.ISTORE + (opcode >> 2),
opcode & 0x3);
} else {
opcode -= 26; // ILOAD_0
mv.visitVarInsn(Opcodes.ILOAD + (opcode >> 2), opcode & 0x3);
}
u += 1;
break;
case ClassWriter.LABEL_INSN:
mv.visitJumpInsn(opcode, labels[offset + readShort(u + 1)]);
u += 3;
break;
case ClassWriter.LABELW_INSN:
mv.visitJumpInsn(opcode - 33, labels[offset + readInt(u + 1)]);
u += 5;
break;
case ClassWriter.WIDE_INSN:
opcode = b[u + 1] & 0xFF;
if (opcode == Opcodes.IINC) {
mv.visitIincInsn(readUnsignedShort(u + 2), readShort(u + 4));
u += 6;
} else {
mv.visitVarInsn(opcode, readUnsignedShort(u + 2));
u += 4;
}
break;
case ClassWriter.TABL_INSN: {
// skips 0 to 3 padding bytes
u = u + 4 - (offset & 3);
// reads instruction
int label = offset + readInt(u);
int min = readInt(u + 4);
int max = readInt(u + 8);
Label[] table = new Label[max - min + 1];
u += 12;
for (int i = 0; i < table.length; ++i) {
table[i] = labels[offset + readInt(u)];
u += 4;
}
mv.visitTableSwitchInsn(min, max, labels[label], table);
break;
}
case ClassWriter.LOOK_INSN: {
// skips 0 to 3 padding bytes
u = u + 4 - (offset & 3);
// reads instruction
int label = offset + readInt(u);
int len = readInt(u + 4);
int[] keys = new int[len];
Label[] values = new Label[len];
u += 8;
for (int i = 0; i < len; ++i) {
keys[i] = readInt(u);
values[i] = labels[offset + readInt(u + 4)];
u += 8;
}
mv.visitLookupSwitchInsn(labels[label], keys, values);
break;
}
case ClassWriter.VAR_INSN:
mv.visitVarInsn(opcode, b[u + 1] & 0xFF);
u += 2;
break;
case ClassWriter.SBYTE_INSN:
mv.visitIntInsn(opcode, b[u + 1]);
u += 2;
break;
case ClassWriter.SHORT_INSN:
mv.visitIntInsn(opcode, readShort(u + 1));
u += 3;
break;
case ClassWriter.LDC_INSN:
mv.visitLdcInsn(readConst(b[u + 1] & 0xFF, c));
u += 2;
break;
case ClassWriter.LDCW_INSN:
mv.visitLdcInsn(readConst(readUnsignedShort(u + 1), c));
u += 3;
break;
case ClassWriter.FIELDORMETH_INSN:
case ClassWriter.ITFMETH_INSN: {
int cpIndex = items[readUnsignedShort(u + 1)];
boolean itf = b[cpIndex - 1] == ClassWriter.IMETH;
String iowner = readClass(cpIndex, c);
cpIndex = items[readUnsignedShort(cpIndex + 2)];
String iname = readUTF8(cpIndex, c);
String idesc = readUTF8(cpIndex + 2, c);
if (opcode < Opcodes.INVOKEVIRTUAL) {
mv.visitFieldInsn(opcode, iowner, iname, idesc);
} else {
mv.visitMethodInsn(opcode, iowner, iname, idesc, itf);
}
if (opcode == Opcodes.INVOKEINTERFACE) {
u += 5;
} else {
u += 3;
}
break;
}
case ClassWriter.INDYMETH_INSN: {
int cpIndex = items[readUnsignedShort(u + 1)];
int bsmIndex = context.bootstrapMethods[readUnsignedShort(cpIndex)];
Handle bsm = (Handle) readConst(readUnsignedShort(bsmIndex), c);
int bsmArgCount = readUnsignedShort(bsmIndex + 2);
Object[] bsmArgs = new Object[bsmArgCount];
bsmIndex += 4;
for (int i = 0; i < bsmArgCount; i++) {
bsmArgs[i] = readConst(readUnsignedShort(bsmIndex), c);
bsmIndex += 2;
}
cpIndex = items[readUnsignedShort(cpIndex + 2)];
String iname = readUTF8(cpIndex, c);
String idesc = readUTF8(cpIndex + 2, c);
mv.visitInvokeDynamicInsn(iname, idesc, bsm, bsmArgs);
u += 5;
break;
}
case ClassWriter.TYPE_INSN:
mv.visitTypeInsn(opcode, readClass(u + 1, c));
u += 3;
break;
case ClassWriter.IINC_INSN:
mv.visitIincInsn(b[u + 1] & 0xFF, b[u + 2]);
u += 3;
break;
// case MANA_INSN:
default:
mv.visitMultiANewArrayInsn(readClass(u + 1, c), b[u + 3] & 0xFF);
u += 4;
break;
}
// visit the instruction annotations, if any
while (tanns != null && tann < tanns.length && ntoff <= offset) {
if (ntoff == offset) {
int v = readAnnotationTarget(context, tanns[tann]);
readAnnotationValues(v + 2, c, true,
mv.visitInsnAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), true));
}
ntoff = ++tann >= tanns.length || readByte(tanns[tann]) < 0x43 ? -1
: readUnsignedShort(tanns[tann] + 1);
}
while (itanns != null && itann < itanns.length && nitoff <= offset) {
if (nitoff == offset) {
int v = readAnnotationTarget(context, itanns[itann]);
readAnnotationValues(v + 2, c, true,
mv.visitInsnAnnotation(context.typeRef,
context.typePath, readUTF8(v, c), false));
}
nitoff = ++itann >= itanns.length
|| readByte(itanns[itann]) < 0x43 ? -1
: readUnsignedShort(itanns[itann] + 1);
}
}
if (labels[codeLength] != null) {
mv.visitLabel(labels[codeLength]);
}
// visits the local variable tables
if ((context.flags & SKIP_DEBUG) == 0 && varTable != 0) {
int[] typeTable = null;
if (varTypeTable != 0) {
u = varTypeTable + 2;
typeTable = new int[readUnsignedShort(varTypeTable) * 3];
for (int i = typeTable.length; i > 0;) {
typeTable[--i] = u + 6; // signature
typeTable[--i] = readUnsignedShort(u + 8); // index
typeTable[--i] = readUnsignedShort(u); // start
u += 10;
}
}
u = varTable + 2;
for (int i = readUnsignedShort(varTable); i > 0; --i) {
int start = readUnsignedShort(u);
int length = readUnsignedShort(u + 2);
int index = readUnsignedShort(u + 8);
String vsignature = null;
if (typeTable != null) {
for (int j = 0; j < typeTable.length; j += 3) {
if (typeTable[j] == start && typeTable[j + 1] == index) {
vsignature = readUTF8(typeTable[j + 2], c);
break;
}
}
}
mv.visitLocalVariable(readUTF8(u + 4, c), readUTF8(u + 6, c),
vsignature, labels[start], labels[start + length],
index);
u += 10;
}
}
// visits the local variables type annotations
if (tanns != null) {
for (int i = 0; i < tanns.length; ++i) {
if ((readByte(tanns[i]) >> 1) == (0x40 >> 1)) {
int v = readAnnotationTarget(context, tanns[i]);
v = readAnnotationValues(v + 2, c, true,
mv.visitLocalVariableAnnotation(context.typeRef,
context.typePath, context.start,
context.end, context.index, readUTF8(v, c),
true));
}
}
}
if (itanns != null) {
for (int i = 0; i < itanns.length; ++i) {
if ((readByte(itanns[i]) >> 1) == (0x40 >> 1)) {
int v = readAnnotationTarget(context, itanns[i]);
v = readAnnotationValues(v + 2, c, true,
mv.visitLocalVariableAnnotation(context.typeRef,
context.typePath, context.start,
context.end, context.index, readUTF8(v, c),
false));
}
}
}
// visits the code attributes
while (attributes != null) {
Attribute attr = attributes.next;
attributes.next = null;
mv.visitAttribute(attributes);
attributes = attr;
}
// visits the max stack and max locals values
mv.visitMaxs(maxStack, maxLocals);
}
/**
* Parses a type annotation table to find the labels, and to visit the try
* catch block annotations.
*
* @param u
* the start offset of a type annotation table.
* @param mv
* the method visitor to be used to visit the try catch block
* annotations.
* @param context
* information about the class being parsed.
* @param visible
* if the type annotation table to parse contains runtime visible
* annotations.
* @return the start offset of each type annotation in the parsed table.
*/
private int[] readTypeAnnotations(final MethodVisitor mv,
final Context context, int u, boolean visible) {
char[] c = context.buffer;
int[] offsets = new int[readUnsignedShort(u)];
u += 2;
for (int i = 0; i < offsets.length; ++i) {
offsets[i] = u;
int target = readInt(u);
switch (target >>> 24) {
case 0x00: // CLASS_TYPE_PARAMETER
case 0x01: // METHOD_TYPE_PARAMETER
case 0x16: // METHOD_FORMAL_PARAMETER
u += 2;
break;
case 0x13: // FIELD
case 0x14: // METHOD_RETURN
case 0x15: // METHOD_RECEIVER
u += 1;
break;
case 0x40: // LOCAL_VARIABLE
case 0x41: // RESOURCE_VARIABLE
for (int j = readUnsignedShort(u + 1); j > 0; --j) {
int start = readUnsignedShort(u + 3);
int length = readUnsignedShort(u + 5);
readLabel(start, context.labels);
readLabel(start + length, context.labels);
u += 6;
}
u += 3;
break;
case 0x47: // CAST
case 0x48: // CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
case 0x49: // METHOD_INVOCATION_TYPE_ARGUMENT
case 0x4A: // CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
case 0x4B: // METHOD_REFERENCE_TYPE_ARGUMENT
u += 4;
break;
// case 0x10: // CLASS_EXTENDS
// case 0x11: // CLASS_TYPE_PARAMETER_BOUND
// case 0x12: // METHOD_TYPE_PARAMETER_BOUND
// case 0x17: // THROWS
// case 0x42: // EXCEPTION_PARAMETER
// case 0x43: // INSTANCEOF
// case 0x44: // NEW
// case 0x45: // CONSTRUCTOR_REFERENCE
// case 0x46: // METHOD_REFERENCE
default:
u += 3;
break;
}
int pathLength = readByte(u);
if ((target >>> 24) == 0x42) {
TypePath path = pathLength == 0 ? null : new TypePath(b, u);
u += 1 + 2 * pathLength;
u = readAnnotationValues(u + 2, c, true,
mv.visitTryCatchAnnotation(target, path,
readUTF8(u, c), visible));
} else {
u = readAnnotationValues(u + 3 + 2 * pathLength, c, true, null);
}
}
return offsets;
}
/**
* Parses the header of a type annotation to extract its target_type and
* target_path (the result is stored in the given context), and returns the
* start offset of the rest of the type_annotation structure (i.e. the
* offset to the type_index field, which is followed by
* num_element_value_pairs and then the name,value pairs).
*
* @param context
* information about the class being parsed. This is where the
* extracted target_type and target_path must be stored.
* @param u
* the start offset of a type_annotation structure.
* @return the start offset of the rest of the type_annotation structure.
*/
private int readAnnotationTarget(final Context context, int u) {
int target = readInt(u);
switch (target >>> 24) {
case 0x00: // CLASS_TYPE_PARAMETER
case 0x01: // METHOD_TYPE_PARAMETER
case 0x16: // METHOD_FORMAL_PARAMETER
target &= 0xFFFF0000;
u += 2;
break;
case 0x13: // FIELD
case 0x14: // METHOD_RETURN
case 0x15: // METHOD_RECEIVER
target &= 0xFF000000;
u += 1;
break;
case 0x40: // LOCAL_VARIABLE
case 0x41: { // RESOURCE_VARIABLE
target &= 0xFF000000;
int n = readUnsignedShort(u + 1);
context.start = new Label[n];
context.end = new Label[n];
context.index = new int[n];
u += 3;
for (int i = 0; i < n; ++i) {
int start = readUnsignedShort(u);
int length = readUnsignedShort(u + 2);
context.start[i] = readLabel(start, context.labels);
context.end[i] = readLabel(start + length, context.labels);
context.index[i] = readUnsignedShort(u + 4);
u += 6;
}
break;
}
case 0x47: // CAST
case 0x48: // CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
case 0x49: // METHOD_INVOCATION_TYPE_ARGUMENT
case 0x4A: // CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
case 0x4B: // METHOD_REFERENCE_TYPE_ARGUMENT
target &= 0xFF0000FF;
u += 4;
break;
// case 0x10: // CLASS_EXTENDS
// case 0x11: // CLASS_TYPE_PARAMETER_BOUND
// case 0x12: // METHOD_TYPE_PARAMETER_BOUND
// case 0x17: // THROWS
// case 0x42: // EXCEPTION_PARAMETER
// case 0x43: // INSTANCEOF
// case 0x44: // NEW
// case 0x45: // CONSTRUCTOR_REFERENCE
// case 0x46: // METHOD_REFERENCE
default:
target &= (target >>> 24) < 0x43 ? 0xFFFFFF00 : 0xFF000000;
u += 3;
break;
}
int pathLength = readByte(u);
context.typeRef = target;
context.typePath = pathLength == 0 ? null : new TypePath(b, u);
return u + 1 + 2 * pathLength;
}
/**
* Reads parameter annotations and makes the given visitor visit them.
*
* @param mv
* the visitor that must visit the annotations.
* @param context
* information about the class being parsed.
* @param v
* start offset in {@link #b b} of the annotations to be read.
* @param visible
* true if the annotations to be read are visible at
* runtime.
*/
private void readParameterAnnotations(final MethodVisitor mv,
final Context context, int v, final boolean visible) {
int i;
int n = b[v++] & 0xFF;
// workaround for a bug in javac (javac compiler generates a parameter
// annotation array whose size is equal to the number of parameters in
// the Java source file, while it should generate an array whose size is
// equal to the number of parameters in the method descriptor - which
// includes the synthetic parameters added by the compiler). This work-
// around supposes that the synthetic parameters are the first ones.
int synthetics = Type.getArgumentTypes(context.desc).length - n;
AnnotationVisitor av;
for (i = 0; i < synthetics; ++i) {
// virtual annotation to detect synthetic parameters in MethodWriter
av = mv.visitParameterAnnotation(i, "Ljava/lang/Synthetic;", false);
if (av != null) {
av.visitEnd();
}
}
char[] c = context.buffer;
for (; i < n + synthetics; ++i) {
int j = readUnsignedShort(v);
v += 2;
for (; j > 0; --j) {
av = mv.visitParameterAnnotation(i, readUTF8(v, c), visible);
v = readAnnotationValues(v + 2, c, true, av);
}
}
}
/**
* Reads the values of an annotation and makes the given visitor visit them.
*
* @param v
* the start offset in {@link #b b} of the values to be read
* (including the unsigned short that gives the number of
* values).
* @param buf
* buffer to be used to call {@link #readUTF8 readUTF8},
* {@link #readClass(int,char[]) readClass} or {@link #readConst
* readConst}.
* @param named
* if the annotation values are named or not.
* @param av
* the visitor that must visit the values.
* @return the end offset of the annotation values.
*/
private int readAnnotationValues(int v, final char[] buf,
final boolean named, final AnnotationVisitor av) {
int i = readUnsignedShort(v);
v += 2;
if (named) {
for (; i > 0; --i) {
v = readAnnotationValue(v + 2, buf, readUTF8(v, buf), av);
}
} else {
for (; i > 0; --i) {
v = readAnnotationValue(v, buf, null, av);
}
}
if (av != null) {
av.visitEnd();
}
return v;
}
/**
* Reads a value of an annotation and makes the given visitor visit it.
*
* @param v
* the start offset in {@link #b b} of the value to be read
* (not including the value name constant pool index).
* @param buf
* buffer to be used to call {@link #readUTF8 readUTF8},
* {@link #readClass(int,char[]) readClass} or {@link #readConst
* readConst}.
* @param name
* the name of the value to be read.
* @param av
* the visitor that must visit the value.
* @return the end offset of the annotation value.
*/
private int readAnnotationValue(int v, final char[] buf, final String name,
final AnnotationVisitor av) {
int i;
if (av == null) {
switch (b[v] & 0xFF) {
case 'e': // enum_const_value
return v + 5;
case '@': // annotation_value
return readAnnotationValues(v + 3, buf, true, null);
case '[': // array_value
return readAnnotationValues(v + 1, buf, false, null);
default:
return v + 3;
}
}
switch (b[v++] & 0xFF) {
case 'I': // pointer to CONSTANT_Integer
case 'J': // pointer to CONSTANT_Long
case 'F': // pointer to CONSTANT_Float
case 'D': // pointer to CONSTANT_Double
av.visit(name, readConst(readUnsignedShort(v), buf));
v += 2;
break;
case 'B': // pointer to CONSTANT_Byte
av.visit(name, (byte) readInt(items[readUnsignedShort(v)]));
v += 2;
break;
case 'Z': // pointer to CONSTANT_Boolean
av.visit(name,
readInt(items[readUnsignedShort(v)]) == 0 ? Boolean.FALSE
: Boolean.TRUE);
v += 2;
break;
case 'S': // pointer to CONSTANT_Short
av.visit(name, (short) readInt(items[readUnsignedShort(v)]));
v += 2;
break;
case 'C': // pointer to CONSTANT_Char
av.visit(name, (char) readInt(items[readUnsignedShort(v)]));
v += 2;
break;
case 's': // pointer to CONSTANT_Utf8
av.visit(name, readUTF8(v, buf));
v += 2;
break;
case 'e': // enum_const_value
av.visitEnum(name, readUTF8(v, buf), readUTF8(v + 2, buf));
v += 4;
break;
case 'c': // class_info
av.visit(name, Type.getType(readUTF8(v, buf)));
v += 2;
break;
case '@': // annotation_value
v = readAnnotationValues(v + 2, buf, true,
av.visitAnnotation(name, readUTF8(v, buf)));
break;
case '[': // array_value
int size = readUnsignedShort(v);
v += 2;
if (size == 0) {
return readAnnotationValues(v - 2, buf, false,
av.visitArray(name));
}
switch (this.b[v++] & 0xFF) {
case 'B':
byte[] bv = new byte[size];
for (i = 0; i < size; i++) {
bv[i] = (byte) readInt(items[readUnsignedShort(v)]);
v += 3;
}
av.visit(name, bv);
--v;
break;
case 'Z':
boolean[] zv = new boolean[size];
for (i = 0; i < size; i++) {
zv[i] = readInt(items[readUnsignedShort(v)]) != 0;
v += 3;
}
av.visit(name, zv);
--v;
break;
case 'S':
short[] sv = new short[size];
for (i = 0; i < size; i++) {
sv[i] = (short) readInt(items[readUnsignedShort(v)]);
v += 3;
}
av.visit(name, sv);
--v;
break;
case 'C':
char[] cv = new char[size];
for (i = 0; i < size; i++) {
cv[i] = (char) readInt(items[readUnsignedShort(v)]);
v += 3;
}
av.visit(name, cv);
--v;
break;
case 'I':
int[] iv = new int[size];
for (i = 0; i < size; i++) {
iv[i] = readInt(items[readUnsignedShort(v)]);
v += 3;
}
av.visit(name, iv);
--v;
break;
case 'J':
long[] lv = new long[size];
for (i = 0; i < size; i++) {
lv[i] = readLong(items[readUnsignedShort(v)]);
v += 3;
}
av.visit(name, lv);
--v;
break;
case 'F':
float[] fv = new float[size];
for (i = 0; i < size; i++) {
fv[i] = Float
.intBitsToFloat(readInt(items[readUnsignedShort(v)]));
v += 3;
}
av.visit(name, fv);
--v;
break;
case 'D':
double[] dv = new double[size];
for (i = 0; i < size; i++) {
dv[i] = Double
.longBitsToDouble(readLong(items[readUnsignedShort(v)]));
v += 3;
}
av.visit(name, dv);
--v;
break;
default:
v = readAnnotationValues(v - 3, buf, false, av.visitArray(name));
}
}
return v;
}
/**
* Computes the implicit frame of the method currently being parsed (as
* defined in the given {@link Context}) and stores it in the given context.
*
* @param frame
* information about the class being parsed.
*/
private void getImplicitFrame(final Context frame) {
String desc = frame.desc;
Object[] locals = frame.local;
int local = 0;
if ((frame.access & Opcodes.ACC_STATIC) == 0) {
if ("".equals(frame.name)) {
locals[local++] = Opcodes.UNINITIALIZED_THIS;
} else {
locals[local++] = readClass(header + 2, frame.buffer);
}
}
int i = 1;
loop: while (true) {
int j = i;
switch (desc.charAt(i++)) {
case 'Z':
case 'C':
case 'B':
case 'S':
case 'I':
locals[local++] = Opcodes.INTEGER;
break;
case 'F':
locals[local++] = Opcodes.FLOAT;
break;
case 'J':
locals[local++] = Opcodes.LONG;
break;
case 'D':
locals[local++] = Opcodes.DOUBLE;
break;
case '[':
while (desc.charAt(i) == '[') {
++i;
}
if (desc.charAt(i) == 'L') {
++i;
while (desc.charAt(i) != ';') {
++i;
}
}
locals[local++] = desc.substring(j, ++i);
break;
case 'L':
while (desc.charAt(i) != ';') {
++i;
}
locals[local++] = desc.substring(j + 1, i++);
break;
default:
break loop;
}
}
frame.localCount = local;
}
/**
* Reads a stack map frame and stores the result in the given
* {@link Context} object.
*
* @param stackMap
* the start offset of a stack map frame in the class file.
* @param zip
* if the stack map frame at stackMap is compressed or not.
* @param unzip
* if the stack map frame must be uncompressed.
* @param frame
* where the parsed stack map frame must be stored.
* @return the offset of the first byte following the parsed frame.
*/
private int readFrame(int stackMap, boolean zip, boolean unzip,
Context frame) {
char[] c = frame.buffer;
Label[] labels = frame.labels;
int tag;
int delta;
if (zip) {
tag = b[stackMap++] & 0xFF;
} else {
tag = MethodWriter.FULL_FRAME;
frame.offset = -1;
}
frame.localDiff = 0;
if (tag < MethodWriter.SAME_LOCALS_1_STACK_ITEM_FRAME) {
delta = tag;
frame.mode = Opcodes.F_SAME;
frame.stackCount = 0;
} else if (tag < MethodWriter.RESERVED) {
delta = tag - MethodWriter.SAME_LOCALS_1_STACK_ITEM_FRAME;
stackMap = readFrameType(frame.stack, 0, stackMap, c, labels);
frame.mode = Opcodes.F_SAME1;
frame.stackCount = 1;
} else {
delta = readUnsignedShort(stackMap);
stackMap += 2;
if (tag == MethodWriter.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
stackMap = readFrameType(frame.stack, 0, stackMap, c, labels);
frame.mode = Opcodes.F_SAME1;
frame.stackCount = 1;
} else if (tag >= MethodWriter.CHOP_FRAME
&& tag < MethodWriter.SAME_FRAME_EXTENDED) {
frame.mode = Opcodes.F_CHOP;
frame.localDiff = MethodWriter.SAME_FRAME_EXTENDED - tag;
frame.localCount -= frame.localDiff;
frame.stackCount = 0;
} else if (tag == MethodWriter.SAME_FRAME_EXTENDED) {
frame.mode = Opcodes.F_SAME;
frame.stackCount = 0;
} else if (tag < MethodWriter.FULL_FRAME) {
int local = unzip ? frame.localCount : 0;
for (int i = tag - MethodWriter.SAME_FRAME_EXTENDED; i > 0; i--) {
stackMap = readFrameType(frame.local, local++, stackMap, c,
labels);
}
frame.mode = Opcodes.F_APPEND;
frame.localDiff = tag - MethodWriter.SAME_FRAME_EXTENDED;
frame.localCount += frame.localDiff;
frame.stackCount = 0;
} else { // if (tag == FULL_FRAME) {
frame.mode = Opcodes.F_FULL;
int n = readUnsignedShort(stackMap);
stackMap += 2;
frame.localDiff = n;
frame.localCount = n;
for (int local = 0; n > 0; n--) {
stackMap = readFrameType(frame.local, local++, stackMap, c,
labels);
}
n = readUnsignedShort(stackMap);
stackMap += 2;
frame.stackCount = n;
for (int stack = 0; n > 0; n--) {
stackMap = readFrameType(frame.stack, stack++, stackMap, c,
labels);
}
}
}
frame.offset += delta + 1;
readLabel(frame.offset, labels);
return stackMap;
}
/**
* Reads a stack map frame type and stores it at the given index in the
* given array.
*
* @param frame
* the array where the parsed type must be stored.
* @param index
* the index in 'frame' where the parsed type must be stored.
* @param v
* the start offset of the stack map frame type to read.
* @param buf
* a buffer to read strings.
* @param labels
* the labels of the method currently being parsed, indexed by
* their offset. If the parsed type is an Uninitialized type, a
* new label for the corresponding NEW instruction is stored in
* this array if it does not already exist.
* @return the offset of the first byte after the parsed type.
*/
private int readFrameType(final Object[] frame, final int index, int v,
final char[] buf, final Label[] labels) {
int type = b[v++] & 0xFF;
switch (type) {
case 0:
frame[index] = Opcodes.TOP;
break;
case 1:
frame[index] = Opcodes.INTEGER;
break;
case 2:
frame[index] = Opcodes.FLOAT;
break;
case 3:
frame[index] = Opcodes.DOUBLE;
break;
case 4:
frame[index] = Opcodes.LONG;
break;
case 5:
frame[index] = Opcodes.NULL;
break;
case 6:
frame[index] = Opcodes.UNINITIALIZED_THIS;
break;
case 7: // Object
frame[index] = readClass(v, buf);
v += 2;
break;
default: // Uninitialized
frame[index] = readLabel(readUnsignedShort(v), labels);
v += 2;
}
return v;
}
/**
* Returns the label corresponding to the given offset. The default
* implementation of this method creates a label for the given offset if it
* has not been already created.
*
* @param offset
* a bytecode offset in a method.
* @param labels
* the already created labels, indexed by their offset. If a
* label already exists for offset this method must not create a
* new one. Otherwise it must store the new label in this array.
* @return a non null Label, which must be equal to labels[offset].
*/
protected Label readLabel(int offset, Label[] labels) {
if (labels[offset] == null) {
labels[offset] = new Label();
}
return labels[offset];
}
/**
* Returns the start index of the attribute_info structure of this class.
*
* @return the start index of the attribute_info structure of this class.
*/
private int getAttributes() {
// skips the header
int u = header + 8 + readUnsignedShort(header + 6) * 2;
// skips fields and methods
for (int i = readUnsignedShort(u); i > 0; --i) {
for (int j = readUnsignedShort(u + 8); j > 0; --j) {
u += 6 + readInt(u + 12);
}
u += 8;
}
u += 2;
for (int i = readUnsignedShort(u); i > 0; --i) {
for (int j = readUnsignedShort(u + 8); j > 0; --j) {
u += 6 + readInt(u + 12);
}
u += 8;
}
// the attribute_info structure starts just after the methods
return u + 2;
}
/**
* Reads an attribute in {@link #b b}.
*
* @param attrs
* prototypes of the attributes that must be parsed during the
* visit of the class. Any attribute whose type is not equal to
* the type of one the prototypes is ignored (i.e. an empty
* {@link Attribute} instance is returned).
* @param type
* the type of the attribute.
* @param off
* index of the first byte of the attribute's content in
* {@link #b b}. The 6 attribute header bytes, containing the
* type and the length of the attribute, are not taken into
* account here (they have already been read).
* @param len
* the length of the attribute's content.
* @param buf
* buffer to be used to call {@link #readUTF8 readUTF8},
* {@link #readClass(int,char[]) readClass} or {@link #readConst
* readConst}.
* @param codeOff
* index of the first byte of code's attribute content in
* {@link #b b}, or -1 if the attribute to be read is not a code
* attribute. The 6 attribute header bytes, containing the type
* and the length of the attribute, are not taken into account
* here.
* @param labels
* the labels of the method's code, or null if the
* attribute to be read is not a code attribute.
* @return the attribute that has been read, or null to skip this
* attribute.
*/
private Attribute readAttribute(final Attribute[] attrs, final String type,
final int off, final int len, final char[] buf, final int codeOff,
final Label[] labels) {
for (int i = 0; i < attrs.length; ++i) {
if (attrs[i].type.equals(type)) {
return attrs[i].read(this, off, len, buf, codeOff, labels);
}
}
return new Attribute(type).read(this, off, len, null, -1, null);
}
// ------------------------------------------------------------------------
// Utility methods: low level parsing
// ------------------------------------------------------------------------
/**
* Returns the number of constant pool items in {@link #b b}.
*
* @return the number of constant pool items in {@link #b b}.
*/
public int getItemCount() {
return items.length;
}
/**
* Returns the start index of the constant pool item in {@link #b b}, plus
* one. This method is intended for {@link Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param item
* the index a constant pool item.
* @return the start index of the constant pool item in {@link #b b}, plus
* one.
*/
public int getItem(final int item) {
return items[item];
}
/**
* Returns the maximum length of the strings contained in the constant pool
* of the class.
*
* @return the maximum length of the strings contained in the constant pool
* of the class.
*/
public int getMaxStringLength() {
return maxStringLength;
}
/**
* Reads a byte value in {@link #b b}. This method is intended for
* {@link Attribute} sub classes, and is normally not needed by class
* generators or adapters.
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
public int readByte(final int index) {
return b[index] & 0xFF;
}
/**
* Reads an unsigned short value in {@link #b b}. This method is intended
* for {@link Attribute} sub classes, and is normally not needed by class
* generators or adapters.
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
public int readUnsignedShort(final int index) {
byte[] b = this.b;
return ((b[index] & 0xFF) << 8) | (b[index + 1] & 0xFF);
}
/**
* Reads a signed short value in {@link #b b}. This method is intended
* for {@link Attribute} sub classes, and is normally not needed by class
* generators or adapters.
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
public short readShort(final int index) {
byte[] b = this.b;
return (short) (((b[index] & 0xFF) << 8) | (b[index + 1] & 0xFF));
}
/**
* Reads a signed int value in {@link #b b}. This method is intended for
* {@link Attribute} sub classes, and is normally not needed by class
* generators or adapters.
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
public int readInt(final int index) {
byte[] b = this.b;
return ((b[index] & 0xFF) << 24) | ((b[index + 1] & 0xFF) << 16)
| ((b[index + 2] & 0xFF) << 8) | (b[index + 3] & 0xFF);
}
/**
* Reads a signed long value in {@link #b b}. This method is intended for
* {@link Attribute} sub classes, and is normally not needed by class
* generators or adapters.
*
* @param index
* the start index of the value to be read in {@link #b b}.
* @return the read value.
*/
public long readLong(final int index) {
long l1 = readInt(index);
long l0 = readInt(index + 4) & 0xFFFFFFFFL;
return (l1 << 32) | l0;
}
/**
* Reads an UTF8 string constant pool item in {@link #b b}. This method
* is intended for {@link Attribute} sub classes, and is normally not needed
* by class generators or adapters.
*
* @param index
* the start index of an unsigned short value in {@link #b b},
* whose value is the index of an UTF8 constant pool item.
* @param buf
* buffer to be used to read the item. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the String corresponding to the specified UTF8 item.
*/
public String readUTF8(int index, final char[] buf) {
int item = readUnsignedShort(index);
if (index == 0 || item == 0) {
return null;
}
String s = strings[item];
if (s != null) {
return s;
}
index = items[item];
return strings[item] = readUTF(index + 2, readUnsignedShort(index), buf);
}
/**
* Reads UTF8 string in {@link #b b}.
*
* @param index
* start offset of the UTF8 string to be read.
* @param utfLen
* length of the UTF8 string to be read.
* @param buf
* buffer to be used to read the string. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the String corresponding to the specified UTF8 string.
*/
private String readUTF(int index, final int utfLen, final char[] buf) {
int endIndex = index + utfLen;
byte[] b = this.b;
int strLen = 0;
int c;
int st = 0;
char cc = 0;
while (index < endIndex) {
c = b[index++];
switch (st) {
case 0:
c = c & 0xFF;
if (c < 0x80) { // 0xxxxxxx
buf[strLen++] = (char) c;
} else if (c < 0xE0 && c > 0xBF) { // 110x xxxx 10xx xxxx
cc = (char) (c & 0x1F);
st = 1;
} else { // 1110 xxxx 10xx xxxx 10xx xxxx
cc = (char) (c & 0x0F);
st = 2;
}
break;
case 1: // byte 2 of 2-byte char or byte 3 of 3-byte char
buf[strLen++] = (char) ((cc << 6) | (c & 0x3F));
st = 0;
break;
case 2: // byte 2 of 3-byte char
cc = (char) ((cc << 6) | (c & 0x3F));
st = 1;
break;
}
}
return new String(buf, 0, strLen);
}
/**
* Reads a class constant pool item in {@link #b b}. This method is
* intended for {@link Attribute} sub classes, and is normally not needed by
* class generators or adapters.
*
* @param index
* the start index of an unsigned short value in {@link #b b},
* whose value is the index of a class constant pool item.
* @param buf
* buffer to be used to read the item. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the String corresponding to the specified class item.
*/
public String readClass(final int index, final char[] buf) {
// computes the start index of the CONSTANT_Class item in b
// and reads the CONSTANT_Utf8 item designated by
// the first two bytes of this CONSTANT_Class item
return readUTF8(items[readUnsignedShort(index)], buf);
}
/**
* Reads a numeric or string constant pool item in {@link #b b}. This
* method is intended for {@link Attribute} sub classes, and is normally not
* needed by class generators or adapters.
*
* @param item
* the index of a constant pool item.
* @param buf
* buffer to be used to read the item. This buffer must be
* sufficiently large. It is not automatically resized.
* @return the {@link Integer}, {@link Float}, {@link Long}, {@link Double},
* {@link String}, {@link Type} or {@link Handle} corresponding to
* the given constant pool item.
*/
public Object readConst(final int item, final char[] buf) {
int index = items[item];
switch (b[index - 1]) {
case ClassWriter.INT:
return readInt(index);
case ClassWriter.FLOAT:
return Float.intBitsToFloat(readInt(index));
case ClassWriter.LONG:
return readLong(index);
case ClassWriter.DOUBLE:
return Double.longBitsToDouble(readLong(index));
case ClassWriter.CLASS:
return Type.getObjectType(readUTF8(index, buf));
case ClassWriter.STR:
return readUTF8(index, buf);
case ClassWriter.MTYPE:
return Type.getMethodType(readUTF8(index, buf));
default: // case ClassWriter.HANDLE_BASE + [1..9]:
int tag = readByte(index);
int[] items = this.items;
int cpIndex = items[readUnsignedShort(index + 1)];
String owner = readClass(cpIndex, buf);
cpIndex = items[readUnsignedShort(cpIndex + 2)];
String name = readUTF8(cpIndex, buf);
String desc = readUTF8(cpIndex + 2, buf);
return new Handle(tag, owner, name, desc);
}
}
}
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