package com.coderising.jvm.method;
import java.util.ArrayList;
import java.util.List;
import com.coderising.jvm.attr.AttributeInfo;
import com.coderising.jvm.attr.CodeAttr;
import com.coderising.jvm.clz.ClassFile;
import com.coderising.jvm.cmd.ByteCodeCommand;
import com.coderising.jvm.constant.ConstantPool;
import com.coderising.jvm.constant.UTF8Info;
import com.coderising.jvm.loader.ByteCodeIterator;
public class Method {
private int accessFlag;
private int nameIndex;
private int descriptorIndex;
private CodeAttr codeAttr;
private ClassFile clzFile;
public Method(ClassFile clzFile,int accessFlag, int nameIndex, int descriptorIndex) {
this.clzFile = clzFile;
this.accessFlag = accessFlag;
this.nameIndex = nameIndex;
this.descriptorIndex = descriptorIndex;
}
public static Method parse(ClassFile clzFile, ByteCodeIterator iter){
int access_flags = iter.nextU2ToInt();
int name_index = iter.nextU2ToInt();
int descriptor_index = iter.nextU2ToInt();
int attrbutes_count = iter.nextU2ToInt();
Method method = new Method(clzFile, access_flags,name_index,descriptor_index);
for (int i = 0; i < attrbutes_count; i++) {
int attr_nameIndex = iter.nextU2ToInt();
String att_name = clzFile.getConstantPool().getUTF8String(attr_nameIndex);
iter.back(2);
if (AttributeInfo.CODE.equalsIgnoreCase("Code")) {
CodeAttr codeAttr = CodeAttr.parse(clzFile, iter);
method.setCodeAttr(codeAttr);
} else {
throw new RuntimeException(att_name + " has not been implemented");
}
}
return method;
}
public ByteCodeCommand[] getCmds() {
return this.getCodeAttr().getCmds();
}
public ClassFile getClzFile() {
return clzFile;
}
public CodeAttr getCodeAttr() {
return codeAttr;
}
public int getDescriptorIndex() {
return descriptorIndex;
}
public int getNameIndex() {
return nameIndex;
}
public void setCodeAttr(CodeAttr code) {
this.codeAttr = code;
}
public String toString() {
ConstantPool pool = this.clzFile.getConstantPool();
StringBuilder buffer = new StringBuilder();
String name = ((UTF8Info)pool.getConstantInfo(this.nameIndex)).getValue();
String desc = ((UTF8Info)pool.getConstantInfo(this.descriptorIndex)).getValue();
buffer.append(name).append(":").append(desc).append("\n");
buffer.append(this.codeAttr.toString(pool));
return buffer.toString();
}
public List<String> getParameterList() {
// e.g. (Ljava/util/List;Ljava/lang/String;II)V
String paramAndType = getParamAndReturnType();
int first = paramAndType.indexOf("(");
int last = paramAndType.lastIndexOf(")");
// e.g. Ljava/util/List;Ljava/lang/String;II
String param = paramAndType.substring(first+1, last);
List<String> paramList = new ArrayList<String>();
if((null == param) || "".equals(param)){
return paramList;
}
while(!param.equals("")){
int pos = 0;
// 这是一个对象类型
if(param.charAt(pos) == 'L'){
int end = param.indexOf(";");
if(end == -1){
throw new RuntimeException("can't find the ; for a object type");
}
paramList.add(param.substring(pos+1,end));
pos = end + 1;
}
else if(param.charAt(pos) == 'I'){
// int
paramList.add("I");
pos ++;
}
else if(param.charAt(pos) == 'F'){
// float
paramList.add("F");
pos ++;
} else{
throw new RuntimeException("the param has unsupported type:" + param);
}
param = param.substring(pos);
}
return paramList;
}
private String getParamAndReturnType() {
UTF8Info nameAndTypeInfo = (UTF8Info)this.getClzFile()
.getConstantPool().getConstantInfo(this.getDescriptorIndex());
return nameAndTypeInfo.getValue();
}
}