package com.coding.mini_jvm.src.com.coderising.jvm.method;
import com.coding.mini_jvm.src.com.coderising.jvm.attr.CodeAttr;
import com.coding.mini_jvm.src.com.coderising.jvm.clz.ClassFile;
import com.coding.mini_jvm.src.com.coderising.jvm.cmd.ByteCodeCommand;
import com.coding.mini_jvm.src.com.coderising.jvm.constant.UTF8Info;
import com.coding.mini_jvm.src.com.coderising.jvm.loader.ByteCodeIterator;
import java.util.ArrayList;
import java.util.List;
public class Method {
private int accessFlag;
private int nameIndex;
private int descriptorIndex;
private CodeAttr codeAttr;
private ClassFile clzFile;
public ClassFile getClzFile() {
return clzFile;
}
public int getNameIndex() {
return nameIndex;
}
public int getDescriptorIndex() {
return descriptorIndex;
}
public CodeAttr getCodeAttr() {
return codeAttr;
}
public void setCodeAttr(CodeAttr code) {
this.codeAttr = code;
}
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 accessFlag = iter.readTwoBytesToInt();
int nameIndex = iter.readTwoBytesToInt();
int descIndex = iter.readTwoBytesToInt();
Method method = new Method(clzFile, accessFlag, nameIndex, descIndex);
int attrCount = iter.readTwoBytesToInt();
if (attrCount > 1)
throw new RuntimeException("other attrbute not impl yet");
for (int i = 0; i < attrCount; i++) {
int attrNameIndex = iter.readTwoBytesToInt();
if ("Code".equals(clzFile.getConstantPool().getUTF8String(attrNameIndex))) {
CodeAttr codeAttr = CodeAttr.parse(clzFile, iter);
method.setCodeAttr(codeAttr);
} else
throw new RuntimeException(" attribute[ " + attrNameIndex + " ] not impl yet");
}
return method;
}
public ByteCodeCommand[] getCmds() {
return this.getCodeAttr().getCmds();
}
public List<String> getParameterList() {
String desc = clzFile.getConstantPool().getUTF8String(descriptorIndex);
int startIndex = desc.indexOf("(") + 1;
int endIndex = desc.lastIndexOf(")") ;
String paramStr = desc.substring(startIndex, endIndex);
List<String> params = new ArrayList<>();
if ("".equals(paramStr)) {
return params;
}
int pos = 0;
int length = paramStr.length();
while (pos < length) {
if ('L' == paramStr.charAt(pos) || '['== paramStr.charAt(pos)) {
for (int i = pos; i < length; i++) {
if (paramStr.charAt(i) == ';') {
params.add(paramStr.substring(pos, i));
pos = ++i;
break;
}
}
} else if ('I' == paramStr.charAt(pos)) {
params.add("int");
pos++;
} else if ('F' == paramStr.charAt(pos)) {
params.add("float");
pos++;
} else {
throw new RuntimeException("not impl param type ["+ paramStr.charAt(pos) +"] yet");
}
}
return params;
}
public boolean isStatic() {
return (accessFlag & 0x0004) != 0;
}
public String getName() {
UTF8Info utf8Info = (UTF8Info)clzFile.getConstantPool().getConstantInfo(nameIndex);
return utf8Info.getValue();
}
}