| /* |
| * 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 static org.apache.commons.io.IOUtils.EOF; |
| |
| 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; |
| import java.util.Objects; |
| |
| /** |
| * {@link InputStream} implementation that can read from String, StringBuffer, |
| * StringBuilder or CharBuffer. |
| * <p> |
| * <strong>Note:</strong> Supports {@link #mark(int)} and {@link #reset()}. |
| * |
| * @since 2.2 |
| */ |
| public class CharSequenceInputStream extends InputStream { |
| |
| private static final int BUFFER_SIZE = 2048; |
| |
| private static final int NO_MARK = -1; |
| |
| private final CharsetEncoder encoder; |
| private final CharBuffer cbuf; |
| private final ByteBuffer bbuf; |
| |
| private int mark_cbuf; // position in cbuf |
| private int mark_bbuf; // position in bbuf |
| |
| /** |
| * Constructor. |
| * |
| * @param cs the input character sequence |
| * @param charset the character set name to use |
| * @param bufferSize the buffer size to use. |
| * @throws IllegalArgumentException if the buffer is not large enough to hold a complete character |
| */ |
| public CharSequenceInputStream(final CharSequence cs, final Charset charset, final int bufferSize) { |
| super(); |
| this.encoder = charset.newEncoder() |
| .onMalformedInput(CodingErrorAction.REPLACE) |
| .onUnmappableCharacter(CodingErrorAction.REPLACE); |
| // Ensure that buffer is long enough to hold a complete character |
| final float maxBytesPerChar = encoder.maxBytesPerChar(); |
| if (bufferSize < maxBytesPerChar) { |
| throw new IllegalArgumentException("Buffer size " + bufferSize + " is less than maxBytesPerChar " + |
| maxBytesPerChar); |
| } |
| this.bbuf = ByteBuffer.allocate(bufferSize); |
| this.bbuf.flip(); |
| this.cbuf = CharBuffer.wrap(cs); |
| this.mark_cbuf = NO_MARK; |
| this.mark_bbuf = NO_MARK; |
| } |
| |
| /** |
| * Constructor, calls {@link #CharSequenceInputStream(CharSequence, Charset, int)}. |
| * |
| * @param cs the input character sequence |
| * @param charset the character set name to use |
| * @param bufferSize the buffer size to use. |
| * @throws IllegalArgumentException if the buffer is not large enough to hold a complete character |
| */ |
| public CharSequenceInputStream(final CharSequence cs, final String charset, final int bufferSize) { |
| this(cs, Charset.forName(charset), bufferSize); |
| } |
| |
| /** |
| * Constructor, calls {@link #CharSequenceInputStream(CharSequence, Charset, int)} |
| * with a buffer size of 2048. |
| * |
| * @param cs the input character sequence |
| * @param charset the character set name to use |
| * @throws IllegalArgumentException if the buffer is not large enough to hold a complete character |
| */ |
| public CharSequenceInputStream(final CharSequence cs, final Charset charset) { |
| this(cs, charset, BUFFER_SIZE); |
| } |
| |
| /** |
| * Constructor, calls {@link #CharSequenceInputStream(CharSequence, String, int)} |
| * with a buffer size of 2048. |
| * |
| * @param cs the input character sequence |
| * @param charset the character set name to use |
| * @throws IllegalArgumentException if the buffer is not large enough to hold a complete character |
| */ |
| public CharSequenceInputStream(final CharSequence cs, final String charset) { |
| this(cs, charset, BUFFER_SIZE); |
| } |
| |
| /** |
| * Fills the byte output buffer from the input char buffer. |
| * |
| * @throws CharacterCodingException |
| * an error encoding data |
| */ |
| private void fillBuffer() throws CharacterCodingException { |
| this.bbuf.compact(); |
| final CoderResult result = this.encoder.encode(this.cbuf, this.bbuf, true); |
| if (result.isError()) { |
| result.throwException(); |
| } |
| this.bbuf.flip(); |
| } |
| |
| @Override |
| public int read(final byte[] array, int off, int len) throws IOException { |
| Objects.requireNonNull(array, "array"); |
| if (len < 0 || (off + len) > array.length) { |
| throw new IndexOutOfBoundsException("Array Size=" + array.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 EOF; |
| } |
| int bytesRead = 0; |
| while (len > 0) { |
| if (this.bbuf.hasRemaining()) { |
| final int chunk = Math.min(this.bbuf.remaining(), len); |
| this.bbuf.get(array, off, chunk); |
| off += chunk; |
| len -= chunk; |
| bytesRead += chunk; |
| } else { |
| fillBuffer(); |
| if (!this.bbuf.hasRemaining() && !this.cbuf.hasRemaining()) { |
| break; |
| } |
| } |
| } |
| return bytesRead == 0 && !this.cbuf.hasRemaining() ? EOF : bytesRead; |
| } |
| |
| @Override |
| public int read() throws IOException { |
| for (;;) { |
| if (this.bbuf.hasRemaining()) { |
| return this.bbuf.get() & 0xFF; |
| } |
| fillBuffer(); |
| if (!this.bbuf.hasRemaining() && !this.cbuf.hasRemaining()) { |
| return EOF; |
| } |
| } |
| } |
| |
| @Override |
| public int read(final byte[] b) throws IOException { |
| return read(b, 0, b.length); |
| } |
| |
| @Override |
| public long skip(long n) throws IOException { |
| /* |
| * This could be made more efficient by using position to skip within the current buffer. |
| */ |
| long skipped = 0; |
| while (n > 0 && available() > 0) { |
| this.read(); |
| n--; |
| skipped++; |
| } |
| return skipped; |
| } |
| |
| /** |
| * Return an estimate of the number of bytes remaining in the byte stream. |
| * @return the count of bytes that can be read without blocking (or returning EOF). |
| * |
| * @throws IOException if an error occurs (probably not possible) |
| */ |
| @Override |
| public int available() throws IOException { |
| // The cached entries are in bbuf; since encoding always creates at least one byte |
| // per character, we can add the two to get a better estimate (e.g. if bbuf is empty) |
| // Note that the previous implementation (2.4) could return zero even though there were |
| // encoded bytes still available. |
| return this.bbuf.remaining() + this.cbuf.remaining(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| // noop |
| } |
| |
| /** |
| * {@inheritDoc} |
| * @param readlimit max read limit (ignored) |
| */ |
| @Override |
| public synchronized void mark(final int readlimit) { |
| this.mark_cbuf = this.cbuf.position(); |
| this.mark_bbuf = this.bbuf.position(); |
| this.cbuf.mark(); |
| this.bbuf.mark(); |
| // It would be nice to be able to use mark & reset on the cbuf and bbuf; |
| // however the bbuf is re-used so that won't work |
| } |
| |
| @Override |
| public synchronized void reset() throws IOException { |
| /* |
| * This is not the most efficient implementation, as it re-encodes from the beginning. |
| * |
| * Since the bbuf is re-used, in general it's necessary to re-encode the data. |
| * |
| * It should be possible to apply some optimisations however: |
| * + use mark/reset on the cbuf and bbuf. This would only work if the buffer had not been (re)filled since |
| * the mark. The code would have to catch InvalidMarkException - does not seem possible to check if mark is |
| * valid otherwise. + Try saving the state of the cbuf before each fillBuffer; it might be possible to |
| * restart from there. |
| */ |
| if (this.mark_cbuf != NO_MARK) { |
| // if cbuf is at 0, we have not started reading anything, so skip re-encoding |
| if (this.cbuf.position() != 0) { |
| this.encoder.reset(); |
| this.cbuf.rewind(); |
| this.bbuf.rewind(); |
| this.bbuf.limit(0); // rewind does not clear the buffer |
| while(this.cbuf.position() < this.mark_cbuf) { |
| this.bbuf.rewind(); // empty the buffer (we only refill when empty during normal processing) |
| this.bbuf.limit(0); |
| fillBuffer(); |
| } |
| } |
| if (this.cbuf.position() != this.mark_cbuf) { |
| throw new IllegalStateException("Unexpected CharBuffer postion: actual=" + cbuf.position() + " " + |
| "expected=" + this.mark_cbuf); |
| } |
| this.bbuf.position(this.mark_bbuf); |
| this.mark_cbuf = NO_MARK; |
| this.mark_bbuf = NO_MARK; |
| } |
| } |
| |
| @Override |
| public boolean markSupported() { |
| return true; |
| } |
| |
| } |