package task5.jvm.loader;
import task5.jvm.clz.AccessFlag;
import task5.jvm.clz.ClassFile;
import task5.jvm.clz.ClassIndex;
import task5.jvm.constant.*;
public class ClassFileParser {
public ClassFile parse(byte[] codes) {
ClassFile classFile = new ClassFile();
ByteCodeIterator iterator = new ByteCodeIterator(codes);
System.out.println(iterator.getMagicNumber());
classFile.setMinorVersion(iterator.next2Bytes());
classFile.setMajorVersion(iterator.next2Bytes());
classFile.setConstPool(parseConstantPool(iterator));
classFile.setAccessFlag(parseAccessFlag(iterator));
classFile.setClassIndex(parseClassIndex(iterator));
return classFile;
}
private AccessFlag parseAccessFlag(ByteCodeIterator iter) {
return new AccessFlag(iter.next2Bytes());
}
private ClassIndex parseClassIndex(ByteCodeIterator iter) {
ClassIndex clazIndex = new ClassIndex();
clazIndex.setThisClassIndex(iter.next2Bytes());
clazIndex.setSuperClassIndex(iter.next2Bytes());
return clazIndex;
}
private ConstantPool parseConstantPool(ByteCodeIterator iter) {
int poolCount = iter.next2Bytes();
ConstantPool pool = new ConstantPool(poolCount);
for (int i = 0; i < poolCount; i++) {
int tag = iter.nextFlag();
if (tag == ConstantInfo.UTF8_INFO) { //utf-8
int length = iter.next2Bytes();
byte[] bytes = iter.getBytes(length);
UTF8Info utf8Info = new UTF8Info(pool);
utf8Info.setValue(new String(bytes));
utf8Info.setLength(length);
pool.addConstantInfo(utf8Info);
} else if (tag == ConstantInfo.STRING_INFO) {
StringInfo stringInfo = new StringInfo(pool);
stringInfo.setIndex(iter.next2Bytes());
pool.addConstantInfo(stringInfo);
} else if (tag == ConstantInfo.CLASS_INFO) {
ClassInfo classInfo = new ClassInfo(pool);
classInfo.setUtf8Index(iter.next2Bytes());
pool.addConstantInfo(classInfo);
} else if (tag == ConstantInfo.FIELD_INFO) {
FieldRefInfo fieldRefInfo = new FieldRefInfo(pool);
fieldRefInfo.setClassInfoIndex(iter.next2Bytes());
fieldRefInfo.setNameAndTypeIndex(iter.next2Bytes());
pool.addConstantInfo(fieldRefInfo);
} else if (tag == ConstantInfo.METHOD_INFO) {
MethodRefInfo methodRefInfo = new MethodRefInfo(pool);
methodRefInfo.setClassInfoIndex(iter.next2Bytes());
methodRefInfo.setNameAndTypeIndex(iter.next2Bytes());
pool.addConstantInfo(methodRefInfo);
} else if (tag == ConstantInfo.NAME_AND_TYPE_INFO) {
NameAndTypeInfo nameAndTypeInfo = new NameAndTypeInfo(pool);
nameAndTypeInfo.setIndex1(iter.next2Bytes());
nameAndTypeInfo.setIndex2(iter.next2Bytes());
pool.addConstantInfo(nameAndTypeInfo);
}
}
return pool;
}
}