/*
* Copyright (C) 2012 Wayne Meissner
*
* This file is part of the JNR project.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jnr.ffi.provider.converters;
import jnr.ffi.Pointer;
import jnr.ffi.annotations.Encoding;
import jnr.ffi.mapper.*;
import java.lang.annotation.Annotation;
import java.lang.ref.Reference;
import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.Arrays;
import java.util.Collection;
import static jnr.ffi.provider.converters.StringUtil.getDecoder;
/**
* Converts a native pointer result into a java String
*/
@FromNativeConverter.NoContext
@FromNativeConverter.Cacheable
public class StringResultConverter implements FromNativeConverter<String, Pointer> {
private static final FromNativeConverter<String, Pointer> DEFAULT = new StringResultConverter(Charset.defaultCharset());
private final ThreadLocal<Reference<CharsetDecoder>> localDecoder = new ThreadLocal<Reference<CharsetDecoder>>();
private final Charset charset;
private final int terminatorWidth;
private StringResultConverter(Charset charset) {
this.charset = charset;
this.terminatorWidth = StringUtil.terminatorWidth(charset);
}
public static FromNativeConverter<String, Pointer> getInstance(Charset cs) {
return Charset.defaultCharset().equals(cs) ? DEFAULT : new StringResultConverter(cs);
}
public static FromNativeConverter<String, Pointer> getInstance(FromNativeContext fromNativeContext) {
Charset charset = Charset.defaultCharset();
if (fromNativeContext instanceof MethodResultContext) {
// See if the interface class has a global @Encoding declaration
Encoding e = getEncoding(Arrays.asList(((MethodResultContext) fromNativeContext).getMethod().getDeclaringClass().getAnnotations()));
if (e != null) {
charset = Charset.forName(e.value());
}
}
// Allow each method to override the default
Encoding e = getEncoding(fromNativeContext.getAnnotations());
if (e != null) {
charset = Charset.forName(e.value());
}
return getInstance(charset);
}
@Override
public String fromNative(Pointer pointer, FromNativeContext context) {
if (pointer == null) {
return null;
}
Search: for (int idx = 0; ; ) {
idx += pointer.indexOf(idx, (byte) 0);
for (int tcount = 1; tcount < terminatorWidth; tcount++) {
if (pointer.getByte(idx + tcount) != 0) {
idx += tcount;
continue Search;
}
}
byte[] bytes = new byte[idx];
pointer.get(0, bytes, 0, bytes.length);
try {
return getDecoder(charset, localDecoder).reset().decode(ByteBuffer.wrap(bytes)).toString();
} catch (CharacterCodingException cce) {
throw new RuntimeException(cce);
}
}
}
@Override
public Class<Pointer> nativeType() {
return Pointer.class;
}
private static Encoding getEncoding(Collection<Annotation> annotations) {
for (Annotation a : annotations) {
if (a instanceof Encoding) {
return (Encoding) a;
}
}
return null;
}
}