org.apache.commons.io.input.CharSequenceInputStream Maven / Gradle / Ivy
Show all versions of commons-io Show documentation
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.io.input;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
/**
* {@link InputStream} implementation that can read from String, StringBuffer,
* StringBuilder or CharBuffer.
*
* Note: Supports {@link #mark(int)} and {@link #reset()}.
*
* @since 2.2
*/
public class CharSequenceInputStream extends InputStream {
private final CharsetEncoder encoder;
private final CharBuffer cbuf;
private final ByteBuffer bbuf;
private int mark;
/**
* Constructor.
*
* @param s the input character sequence
* @param charset the character set name to use
* @param bufferSize the buffer size to use.
*/
public CharSequenceInputStream(final CharSequence s, final Charset charset, int bufferSize) {
super();
this.encoder = charset.newEncoder()
.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE);
this.bbuf = ByteBuffer.allocate(bufferSize);
this.bbuf.flip();
this.cbuf = CharBuffer.wrap(s);
this.mark = -1;
}
/**
* Constructor, calls {@link #CharSequenceInputStream(CharSequence, Charset, int)}.
*
* @param s the input character sequence
* @param charset the character set name to use
* @param bufferSize the buffer size to use.
*/
public CharSequenceInputStream(final CharSequence s, final String charset, int bufferSize) {
this(s, Charset.forName(charset), bufferSize);
}
/**
* Constructor, calls {@link #CharSequenceInputStream(CharSequence, Charset, int)}
* with a buffer size of 2048.
*
* @param s the input character sequence
* @param charset the character set name to use
*/
public CharSequenceInputStream(final CharSequence s, final Charset charset) {
this(s, charset, 2048);
}
/**
* Constructor, calls {@link #CharSequenceInputStream(CharSequence, String, int)}
* with a buffer size of 2048.
*
* @param s the input character sequence
* @param charset the character set name to use
*/
public CharSequenceInputStream(final CharSequence s, final String charset) {
this(s, charset, 2048);
}
/**
* Fills the byte output buffer from the input char buffer.
*
* @throws CharacterCodingException
* an error encoding data
*/
private void fillBuffer() throws CharacterCodingException {
this.bbuf.compact();
CoderResult result = this.encoder.encode(this.cbuf, this.bbuf, true);
if (result.isError()) {
result.throwException();
}
this.bbuf.flip();
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (b == null) {
throw new NullPointerException("Byte array is null");
}
if (len < 0 || (off + len) > b.length) {
throw new IndexOutOfBoundsException("Array Size=" + b.length +
", offset=" + off + ", length=" + len);
}
if (len == 0) {
return 0; // must return 0 for zero length read
}
if (!this.bbuf.hasRemaining() && !this.cbuf.hasRemaining()) {
return -1;
}
int bytesRead = 0;
while (len > 0) {
if (this.bbuf.hasRemaining()) {
int chunk = Math.min(this.bbuf.remaining(), len);
this.bbuf.get(b, off, chunk);
off += chunk;
len -= chunk;
bytesRead += chunk;
} else {
fillBuffer();
if (!this.bbuf.hasRemaining() && !this.cbuf.hasRemaining()) {
break;
}
}
}
return bytesRead == 0 && !this.cbuf.hasRemaining() ? -1 : bytesRead;
}
@Override
public int read() throws IOException {
for (;;) {
if (this.bbuf.hasRemaining()) {
return this.bbuf.get() & 0xFF;
} else {
fillBuffer();
if (!this.bbuf.hasRemaining() && !this.cbuf.hasRemaining()) {
return -1;
}
}
}
}
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
@Override
public long skip(long n) throws IOException {
int skipped = 0;
while (n > 0 && this.cbuf.hasRemaining()) {
this.cbuf.get();
n--;
skipped++;
}
return skipped;
}
@Override
public int available() throws IOException {
return this.cbuf.remaining();
}
@Override
public void close() throws IOException {
}
/**
* {@inheritDoc}
* @param readlimit max read limit (ignored)
*/
@Override
public synchronized void mark(@SuppressWarnings("unused") int readlimit) {
this.mark = this.cbuf.position();
}
@Override
public synchronized void reset() throws IOException {
if (this.mark != -1) {
this.cbuf.position(this.mark);
this.mark = -1;
}
}
@Override
public boolean markSupported() {
return true;
}
}