package com.coding.basic.homework_04.jvm.cmd;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import com.coding.basic.homework_04.jvm.clz.ClassFile;
public class CommandParser {
public static final String aconst_null = "01";
public static final String new_object = "BB";
public static final String lstore = "37";
public static final String invokespecial = "B7";
public static final String invokevirtual = "B6";
public static final String getfield = "B4";
public static final String putfield = "B5";
public static final String getstatic = "B2";
public static final String ldc = "12";
public static final String dup = "59";
public static final String bipush = "10";
public static final String aload_0 = "2A";
public static final String aload_1 = "2B";
public static final String aload_2 = "2C";
public static final String iload = "15";
public static final String iload_1 = "1B";
public static final String iload_2 = "1C";
public static final String iload_3 = "1D";
public static final String fload_3 = "25";
public static final String voidreturn = "B1";
public static final String ireturn = "AC";
public static final String freturn = "AE";
public static final String astore_1 = "4C";
public static final String if_icmp_ge = "A2";
public static final String if_icmple = "A4";
public static final String goto_no_condition = "A7";
public static final String iconst_0 = "03";
public static final String iconst_1 = "04";
public static final String istore_1 = "3C";
public static final String istore_2 = "3D";
public static final String iadd = "60";
public static final String iinc = "84";
public static ByteCodeCommand[] parse(ClassFile clzFile, String codes) {
//?为啥是大写的
codes = codes.toUpperCase();
CommandIterator iterator = new CommandIterator(codes);
List<ByteCodeCommand> commands = new ArrayList<ByteCodeCommand>();
while(iterator.hasNext()){
String opCode = iterator.next2CharAsString();
if(new_object.equals(opCode)){
NewObjectCmd cmd = new NewObjectCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(ldc.equals(opCode)){
LdcCmd cmd = new LdcCmd(clzFile, opCode);
cmd.setOperand(iterator.next2CharAsInt());
commands.add(cmd);
}else if(bipush.equals(opCode)){
BiPushCmd cmd = new BiPushCmd(clzFile, opCode);
cmd.setOperand(iterator.next2CharAsInt());
commands.add(cmd);
}else if(invokespecial.equals(opCode)){
InvokeSpecialCmd cmd = new InvokeSpecialCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(invokevirtual.equals(opCode)){
InvokeVirtualCmd cmd = new InvokeVirtualCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(getfield.equals(opCode)){
GetFieldCmd cmd = new GetFieldCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(putfield.equals(opCode)){
PutFieldCmd cmd = new PutFieldCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(getstatic.equals(opCode)){
GetStaticFieldCmd cmd = new GetStaticFieldCmd(clzFile, opCode);
cmd.setOprand1(iterator.next2CharAsInt());
cmd.setOprand2(iterator.next2CharAsInt());
commands.add(cmd);
}else if(dup.equals(opCode) || astore_1.equals(opCode) || aload_0.equals(opCode) ||
aload_1.equals(opCode) || aload_2.equals(opCode) || iload.equals(opCode) || iload_1.equals(opCode)|| iload_2.equals(opCode) || iload_3.equals(opCode) || fload_3.equals(opCode) ||
voidreturn.equals(opCode)){
NoOperandCmd cmd = new NoOperandCmd(clzFile, opCode);
commands.add(cmd);
}else{
throw new RuntimeException("sorry , the java instruction " + opCode + "has not implemented");
}
}
//计算偏移量
calcuateOffset(commands);
ByteCodeCommand[] result = new ByteCodeCommand[commands.size()];
commands.toArray(result);
return result;
}
private static void calcuateOffset(List<ByteCodeCommand> cmds) {
int offset = 0;
for (ByteCodeCommand cmd : cmds) {
cmd.setOffset(offset);
offset += cmd.getLength();
}
}
private static class CommandIterator {
String codes = null;
int pos = 0;
CommandIterator(String codes) {
this.codes = codes;
}
public boolean hasNext() {
return pos < this.codes.length();
}
public String next2CharAsString() {
String result = codes.substring(pos, pos + 2);
pos += 2;
return result;
}
public int next2CharAsInt() {
String s = this.next2CharAsString();
return Integer.valueOf(s, 16).intValue();
}
}
}