package jp.ac.kobe_u.cs.prolog.builtin;
import java.io.PushbackReader;
import jp.ac.kobe_u.cs.prolog.lang.DoubleTerm;
import jp.ac.kobe_u.cs.prolog.lang.ExistenceException;
import jp.ac.kobe_u.cs.prolog.lang.IllegalDomainException;
import jp.ac.kobe_u.cs.prolog.lang.IntegerTerm;
import jp.ac.kobe_u.cs.prolog.lang.JavaException;
import jp.ac.kobe_u.cs.prolog.lang.JavaObjectTerm;
import jp.ac.kobe_u.cs.prolog.lang.ListTerm;
import jp.ac.kobe_u.cs.prolog.lang.PInstantiationException;
import jp.ac.kobe_u.cs.prolog.lang.PermissionException;
import jp.ac.kobe_u.cs.prolog.lang.Predicate;
import jp.ac.kobe_u.cs.prolog.lang.Prolog;
import jp.ac.kobe_u.cs.prolog.lang.SymbolTerm;
import jp.ac.kobe_u.cs.prolog.lang.Term;
import jp.ac.kobe_u.cs.prolog.lang.Token;
/**
* <code>'$read_token0'/3</code><br>
*
* @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
* @author Naoyuki Tamura (tamura@kobe-u.ac.jp)
* @version 1.0
* @since 0.7
*/
class PRED_$read_token0_3 extends Predicate {
/**
*
*/
private static final long serialVersionUID = -6332608975014145565L;
private Term arg1, arg2, arg3;
public PRED_$read_token0_3(Term a1, Term a2, Term a3, Predicate cont) {
arg1 = a1;
arg2 = a2;
arg3 = a3;
this.cont = cont;
}
public PRED_$read_token0_3() {
}
@Override
public void setArgument(Term[] args, Predicate cont) {
arg1 = args[0];
arg2 = args[1];
arg3 = args[2];
this.cont = cont;
}
@Override
public int arity() {
return 3;
}
@Override
public String toString() {
return "$read_token0(" + arg1 + ", " + arg2 + "," + arg3 + ")";
}
/*
* The a1 must be user, user_input, and java.io.PushbackReader, otherwise
* fails.
*/
@Override
public Predicate exec(Prolog engine) {
engine.setB0();
Term a1, a2, a3;
a1 = arg1;
a2 = arg2;
a3 = arg3;
Object stream = null;
StringBuffer s;
int type;
Term token;
// S_or_a
a1 = a1.dereference();
if (a1.isVariable()) {
throw new PInstantiationException(this, 1);
} else if (a1.isSymbol()) {
if (!engine.getStreamManager().containsKey(a1)) {
throw new ExistenceException(this, 1, "stream", a1, "");
}
stream = ((JavaObjectTerm) engine.getStreamManager().get(a1))
.object();
} else if (a1.isJavaObject()) {
stream = ((JavaObjectTerm) a1).object();
} else {
throw new IllegalDomainException(this, 1, "stream_or_alias", a1);
}
if (!(stream instanceof PushbackReader)) {
throw new PermissionException(this, "input", "stream", a1, "");
}
// read token
s = new StringBuffer();
try {
type = Token.read_token(s, (PushbackReader) stream);
switch (type) {
case 'I':
token = new IntegerTerm(Integer.parseInt(s.toString()));
break;
case 'D':
token = new DoubleTerm(Double.parseDouble(s.toString()));
break;
case 'S':
char[] chars = s.toString().toCharArray();
token = Prolog.Nil;
for (int i = chars.length; i > 0; i--) {
token = new ListTerm(new IntegerTerm(chars[i - 1]), token);
}
break;
default:
token = SymbolTerm.makeSymbol(s.toString());
break;
}
} catch (Exception e) {
throw new JavaException(this, 1, e);
}
if (!a2.unify(new IntegerTerm(type), engine.trail)) {
return engine.fail();
}
if (!a3.unify(token, engine.trail)) {
return engine.fail();
}
return cont;
}
}