package miniJVM.cmd;
import miniJVM.clz.ClassFile;
import java.util.ArrayList;
import java.util.List;
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) {
CommandIterator ci = new CommandIterator(codes);
List<ByteCodeCommand> cmds = new ArrayList<ByteCodeCommand>();
while (ci.hasNext()){
String command = ci.next2CharAsString();
if(command.equalsIgnoreCase(new_object)){
NewObjectCmd cmd = new NewObjectCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(invokespecial)){
InvokeSpecialCmd cmd = new InvokeSpecialCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(invokevirtual)){
InvokeVirtualCmd cmd = new InvokeVirtualCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(getfield)){
GetFieldCmd cmd = new GetFieldCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(getstatic)){
GetStaticFieldCmd cmd = new GetStaticFieldCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(putfield)){
PutFieldCmd cmd = new PutFieldCmd(clzFile, command);
cmd.setOprand1(ci.next2CharAsInt());
cmd.setOprand2(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(ldc)){
LdcCmd cmd = new LdcCmd(clzFile, command);
cmd.setOperand(ci.next2CharAsInt());
cmds.add(cmd);
}else if(command.equalsIgnoreCase(bipush)){
BiPushCmd cmd = new BiPushCmd(clzFile, command);
cmd.setOperand(ci.next2CharAsInt());
cmds.add(cmd);
}else if (command.equalsIgnoreCase(dup) ||
command.equalsIgnoreCase(aload_0) ||
command.equalsIgnoreCase(aload_1) ||
command.equalsIgnoreCase(aload_2) ||
command.equalsIgnoreCase(iload_1) ||
command.equalsIgnoreCase(iload_2) ||
command.equalsIgnoreCase(iload_3) ||
command.equalsIgnoreCase(fload_3) ||
command.equalsIgnoreCase(voidreturn) ||
command.equalsIgnoreCase(astore_1)) {
NoOperandCmd cmd = new NoOperandCmd(clzFile, command);
cmds.add(cmd);
}else{
throw new RuntimeException("没有对指令=" + command + "进行处理");
}
}
calculateOffset(cmds);
ByteCodeCommand[] cmdArr = new ByteCodeCommand[cmds.size()];
cmds.toArray(cmdArr);
return cmdArr;
}
private static void calculateOffset(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();
}
}
}