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ClassReader.java
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ClassReader.java
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package org.tinylcy;
import org.tinylcy.accessflags.AccessFlags;
import org.tinylcy.accessflags.ClassAccessFlags;
import org.tinylcy.attributeinfo.BasicAttributeInfo;
import org.tinylcy.basictype.U1;
import org.tinylcy.basictype.U2;
import org.tinylcy.basictype.U4;
import org.tinylcy.constantpool.*;
import java.io.InputStream;
import java.util.ArrayList;
/**
* Created by chenyangli.
*/
public class ClassReader {
public static void analyze(InputStream inputStream) {
ClassFile classFile = read(inputStream);
ConstantPool constantPool = new ConstantPool(classFile.constantPoolCount.getValue());
constantPool.setCpInfo(classFile.cpInfo);
System.out.println("magic = " + classFile.magic.getHexValue());
System.out.println("minorVersion = " + classFile.minorVersion.getValue());
System.out.println("majorVersion = " + classFile.majorVersion.getValue());
System.out.println("constantPoolCount = " + classFile.constantPoolCount.getValue());
for (int i = 0; classFile.cpInfo != null && i < classFile.cpInfo.length; i++) {
System.out.println("cpInfo[" + (i + 1) + "] = " + classFile.cpInfo[i]);
}
System.out.println("accessFlags = " + classFile.accessFlags.getHexValue() +
", " + AccessFlags.getFormattedAccessFlags(new ClassAccessFlags(), classFile.accessFlags.getValue()));
System.out.println("thisClass = " + classFile.thisClass.getValue() +
", this class name = " + getConstantClassInfoValue(constantPool, classFile.thisClass.getValue()));
System.out.println("superClass = " + classFile.superClass.getValue() +
", super class name = " + getConstantClassInfoValue(constantPool, classFile.superClass.getValue()));
System.out.println("interfacesCount = " + classFile.interfacesCount.getValue());
for (int i = 0; i < classFile.interfacesCount.getValue(); i++) {
System.out.println("interfaces[" + i + "] = " + classFile.interfaces[i].getValue() +
", interface name = " + getConstantClassInfoValue(constantPool, classFile.interfaces[i].getValue()));
}
System.out.println("fieldsCount = " + classFile.fieldsCount.getValue());
for (int i = 0; i < classFile.fieldsCount.getValue(); i++) {
System.out.println("fields[" + i + "] = " + classFile.fields[i]);
}
System.out.println("methodsCount = " + classFile.methodsCount.getValue());
for (int i = 0; i < classFile.methodsCount.getValue(); i++) {
System.out.println("methods[" + i + "] = " + classFile.methods[i]);
}
System.out.println("attributesCount = " + classFile.attributesCount.getValue());
for (int i = 0; i < classFile.attributesCount.getValue(); i++) {
System.out.println("attributes[" + i + "] = " + classFile.attributes[i]);
}
}
public static ClassFile read(InputStream inputStream) {
ClassFile classFile = new ClassFile();
classFile.magic = U4.read(inputStream);
classFile.minorVersion = U2.read(inputStream);
classFile.majorVersion = U2.read(inputStream);
classFile.constantPoolCount = U2.read(inputStream);
ConstantPool constantPool = readConstantPool(inputStream,
(short) (classFile.constantPoolCount.getValue() - 1));
classFile.cpInfo = constantPool == null ? null : constantPool.getCpInfo();
classFile.accessFlags = U2.read(inputStream);
classFile.thisClass = U2.read(inputStream);
classFile.superClass = U2.read(inputStream);
classFile.interfacesCount = U2.read(inputStream);
classFile.interfaces = new U2[classFile.interfacesCount.getValue()];
readInterfaces(inputStream, classFile, classFile.interfacesCount.getValue());
classFile.fieldsCount = U2.read(inputStream);
readFieldsInfo(constantPool, inputStream, classFile, classFile.fieldsCount.getValue());
classFile.methodsCount = U2.read(inputStream);
readMethodsInfo(constantPool, inputStream, classFile, classFile.methodsCount.getValue());
classFile.attributesCount = U2.read(inputStream);
readClassAttributesInfo(constantPool, inputStream, classFile, classFile.attributesCount.getValue());
return classFile;
}
public static ConstantPool readConstantPool(InputStream inputStream, short constantPoolCount) {
ConstantPool constantPool = new ConstantPool(constantPoolCount);
ArrayList<ConstantPoolInfo> infoList = new ArrayList<ConstantPoolInfo>();
for (short i = 0; i < constantPoolCount; i++) {
U1 tag = U1.read(inputStream);
ConstantPoolInfo info = newConstantPoolInfo(tag, inputStream);
infoList.add(info);
if (tag.getValue() == ConstantPoolInfo.CONSTANT_LONG_INFO ||
tag.getValue() == ConstantPoolInfo.CONSTANT_DOUBLE_INFO) {
i++;
infoList.add(null);
}
}
constantPool.setCpInfo(infoList.toArray(new ConstantPoolInfo[0]));
return constantPool;
}
private static ConstantPoolInfo newConstantPoolInfo(U1 tag, InputStream inputStream) {
int tagValue = tag.getValue();
ConstantPoolInfo constantPoolInfo = null;
switch (tagValue) {
case ConstantPoolInfo.CONSTANT_UTF8_INFO:
constantPoolInfo = new ConstantUtf8Info(ConstantPoolInfo.CONSTANT_UTF8_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_INTEGER_INFO:
constantPoolInfo = new ConstantIntegerInfo(ConstantPoolInfo.CONSTANT_INTEGER_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_FLOAT_INFO:
constantPoolInfo = new ConstantFloatInfo(ConstantPoolInfo.CONSTANT_FLOAT_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_LONG_INFO:
constantPoolInfo = new ConstantLongInfo(ConstantPoolInfo.CONSTANT_LONG_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_DOUBLE_INFO:
constantPoolInfo = new ConstantDoubleInfo(ConstantPoolInfo.CONSTANT_DOUBLE_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_CLASS_INFO:
constantPoolInfo = new ConstantClassInfo(ConstantPoolInfo.CONSTANT_CLASS_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_STRING_INFO:
constantPoolInfo = new ConstantClassInfo(ConstantPoolInfo.CONSTANT_STRING_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_FIELDREF_INFO:
constantPoolInfo = new ConstantFieldRefInfo(ConstantPoolInfo.CONSTANT_FIELDREF_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_METHODREF_INFO:
constantPoolInfo = new ConstantMethodRefInfo(ConstantPoolInfo.CONSTANT_METHODREF_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_INTERFACEMETHODREF_INFO:
constantPoolInfo = new ConstantInterfaceMethodRefInfo(ConstantPoolInfo.CONSTANT_INTERFACEMETHODREF_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_NAMEANDTYPE_INFO:
constantPoolInfo = new ConstantNameAndTypeInfo(ConstantPoolInfo.CONSTANT_NAMEANDTYPE_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_METHODHANDLE_INFO:
constantPoolInfo = new ConstantMethodHandleInfo(ConstantPoolInfo.CONSTANT_METHODHANDLE_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_METHODTYPE_INFO:
constantPoolInfo = new ConstantMethodTypeInfo(ConstantPoolInfo.CONSTANT_METHODTYPE_INFO);
constantPoolInfo.read(inputStream);
break;
case ConstantPoolInfo.CONSTANT_INVOKEDYNAMIC_INFO:
constantPoolInfo = new ConstantInvokeDynamicInfo(ConstantPoolInfo.CONSTANT_INVOKEDYNAMIC_INFO);
constantPoolInfo.read(inputStream);
break;
}
return constantPoolInfo;
}
public static void readInterfaces(InputStream inputStream, ClassFile classFile, short interfacesCount) {
for (int i = 0; i < interfacesCount; i++) {
classFile.interfaces[i] = U2.read(inputStream);
}
}
public static void readFieldsInfo(ConstantPool constantPool, InputStream inputStream, ClassFile classFile, short fieldsCount) {
ArrayList<FieldInfo> fieldInfoList = new ArrayList<FieldInfo>();
for (int i = 0; i < fieldsCount; i++) {
FieldInfo fieldInfo = new FieldInfo(constantPool);
fieldInfo.read(inputStream);
fieldInfoList.add(fieldInfo);
}
classFile.fields = fieldInfoList.toArray(new FieldInfo[0]);
}
public static void readMethodsInfo(ConstantPool constantPool, InputStream inputStream,
ClassFile classFile, short methodsCount) {
classFile.methods = new MethodInfo[methodsCount];
for (int i = 0; i < methodsCount; i++) {
MethodInfo methodInfo = new MethodInfo(constantPool);
methodInfo.read(inputStream);
classFile.methods[i] = methodInfo;
}
}
public static void readClassAttributesInfo(ConstantPool constantPool, InputStream inputStream,
ClassFile classFile, short classAttributesCount) {
classFile.attributes = new BasicAttributeInfo[classAttributesCount];
for (int i = 0; i < classAttributesCount; i++) {
short attributeNameIndex = U2.read(inputStream).getValue();
BasicAttributeInfo attributeInfo = BasicAttributeInfo.newAttributeInfo(constantPool, attributeNameIndex);
attributeInfo.read(inputStream);
classFile.attributes[i] = attributeInfo;
}
}
private static String getConstantClassInfoValue(ConstantPool constantPool, short constantClassInfoIndex) {
if (constantClassInfoIndex == 0) { return "No super class"; } // If current class is `java.lang.Object.class`, this class doesn't have super class.
ConstantClassInfo constantClassInfo = (ConstantClassInfo) constantPool.getCpInfo()[constantClassInfoIndex - 1];
short index = constantClassInfo.getIndex();
ConstantUtf8Info constantUtf8Info = ((ConstantUtf8Info) (constantPool.getCpInfo()[index - 1]));
return constantUtf8Info.getValue();
}
}