package com.coderising.jvm.loader;
import com.coderising.jvm.util.Util;
import java.util.Arrays;
public class ByteCodeIterator {
byte[] codes;
int pos = 0;
public ByteCodeIterator(byte[] codes) {
this.codes = codes;
}
public byte[] getBytes(int len) {
if (pos + len >= codes.length) {
throw new ArrayIndexOutOfBoundsException();
}
byte[] data = Arrays.copyOfRange(codes, pos, pos + len);
pos = pos + len;
return data;
}
public int nextU1toInt() {
return Util.byteToInt(new byte[]{codes[pos++]});
}
public int nextU2toInt() {
return Util.byteToInt(new byte[]{codes[pos++], codes[pos++]});
}
public int nextU4toInt() {
return Util.byteToInt(new byte[]{codes[pos++], codes[pos++], codes[pos++], codes[pos++]});
}
public String nextU4ToHexString(){
return Util.byteToHexString(new byte[]{codes[pos++], codes[pos++], codes[pos++], codes[pos++]});
}
public String nextUxToHexString(int len){
byte[] temp = new byte[len];
for (int i = 0; i < len; i++) {
temp[i] = codes[pos++];
}
return Util.byteToHexString(temp).toLowerCase();
}
public void back(int n){
pos = pos - n;
}
}