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package com.googlecode.prolog_cafe.builtin;
import com.googlecode.prolog_cafe.lang.*;
import java.io.*;
/**
<code>open/4</code><br>
@author Mutsunori Banbara (banbara@kobe-u.ac.jp)
@author Naoyuki Tamura (tamura@kobe-u.ac.jp)
@version 1.0
*/
public class PRED_open_4 extends Predicate.P4 {
private static final SymbolTerm SYM_NIL = SymbolTerm.makeSymbol("[]");
private static final SymbolTerm SYM_TEXT = SymbolTerm.makeSymbol("text");
private static final SymbolTerm SYM_READ = SymbolTerm.makeSymbol("read");
private static final SymbolTerm SYM_WRITE = SymbolTerm.makeSymbol("write");
private static final SymbolTerm SYM_APPEND = SymbolTerm.makeSymbol("append");
private static final SymbolTerm SYM_INPUT = SymbolTerm.makeSymbol("input");
private static final SymbolTerm SYM_OUTPUT = SymbolTerm.makeSymbol("output");
private static final SymbolTerm SYM_ALIAS_1 = SymbolTerm.makeSymbol("alias", 1);
private static final SymbolTerm SYM_MODE_1 = SymbolTerm.makeSymbol("mode", 1);
private static final SymbolTerm SYM_TYPE_1 = SymbolTerm.makeSymbol("type", 1);
private static final SymbolTerm SYM_FILE_NAME_1 = SymbolTerm.makeSymbol("file_name", 1);
public PRED_open_4(Term a1, Term a2, Term a3, Term a4, Operation cont) {
arg1 = a1;
arg2 = a2;
arg3 = a3;
arg4 = a4;
this.cont = cont;
}
public Operation exec(Prolog engine) {
engine.setB0();
File file;
Term alias = null;
Term opts = SYM_NIL;
JavaObjectTerm streamObject;
Term a1, a2, a3, a4;
a1 = arg1;
a2 = arg2;
a3 = arg3;
a4 = arg4;
// stream
a3 = a3.dereference();
if (! a3.isVariable())
throw new IllegalTypeException(this, 3, "variable", a3);
// source_sink
a1 = a1.dereference();
if (a1.isVariable())
throw new PInstantiationException(this, 1);
if (! a1.isSymbol())
throw new IllegalDomainException(this, 1, "source_sink", a1);
file = new File(((SymbolTerm) a1).name());
// io_mode
a2 = a2.dereference();
if (a2.isVariable())
throw new PInstantiationException(this, 2);
if (! a2.isSymbol())
throw new IllegalTypeException(this, 2, "atom", a2);
try {
if (a2.equals(SYM_READ)) {
if (! file.exists())
throw new ExistenceException(this, 1, "source_sink", a1, "");
PushbackReader in =
new PushbackReader(new BufferedReader(new FileReader(file)), engine.PUSHBACK_SIZE);
streamObject = new JavaObjectTerm(in);
opts = new ListTerm(SYM_INPUT, opts);
} else if (a2.equals(SYM_WRITE)) {
PrintWriter out =
new PrintWriter(new BufferedWriter(new FileWriter(file, false)));
streamObject = new JavaObjectTerm(out);
opts = new ListTerm(SYM_OUTPUT, opts);
} else if (a2.equals(SYM_APPEND)) {
PrintWriter out =
new PrintWriter(new BufferedWriter(new FileWriter(file, true)));
streamObject = new JavaObjectTerm(out);
opts = new ListTerm(SYM_OUTPUT, opts);
} else {
throw new IllegalDomainException(this, 2, "io_mode", a2);
}
} catch (IOException e) {
throw new PermissionException(this, "open", "source_sink", a1, "");
}
if (engine.getStreamManager().containsKey(streamObject))
throw new InternalException("stream object is duplicated");
// stream_options
a4 = a4.dereference();
Term tmp = a4;
while (! tmp.isNil()) {
if (tmp.isVariable())
throw new PInstantiationException(this, 4);
if (! tmp.isList())
throw new IllegalTypeException(this, 4, "list", a4);
Term car = ((ListTerm) tmp).car().dereference();
if (car.isVariable())
throw new PInstantiationException(this, 4);
if (car.isStructure()) {
SymbolTerm functor = ((StructureTerm) car).functor();
Term[] args = ((StructureTerm) car).args();
if (functor.equals(SYM_ALIAS_1)) {
alias = args[0].dereference();
if (! alias.isSymbol())
throw new IllegalDomainException(this, 4, "stream_option", car);
if (engine.getStreamManager().containsKey(alias))
throw new PermissionException(this, "open", "source_sink", car, "");
} else {
throw new IllegalDomainException(this, 4, "stream_option", car);
}
} else {
throw new IllegalDomainException(this, 4, "stream_option", car);
}
tmp = ((ListTerm) tmp).cdr().dereference();
}
opts = new ListTerm(new StructureTerm(SYM_TYPE_1, SYM_TEXT), opts);
opts = new ListTerm(new StructureTerm(SYM_MODE_1, a2), opts);
opts = new ListTerm(new StructureTerm(SYM_FILE_NAME_1, SymbolTerm.makeSymbol(file.getAbsolutePath())), opts);
if (alias != null) {
engine.getStreamManager().put(alias, streamObject);
opts = new ListTerm(new StructureTerm(SYM_ALIAS_1, alias), opts);
}
((VariableTerm)a3).bind(streamObject, engine.trail);
engine.getStreamManager().put(streamObject, opts);
return cont;
}
}
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