/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
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*
* This class is not thread safe. * * @since 4.0 */ public class ExpandableBuffer { public final static int INPUT_MODE = 0; public final static int OUTPUT_MODE = 1; private int mode; private ByteBuffer buffer; /** * Allocates buffer of the given size using the given allocator. * * @param buffersize the buffer size. */ protected ExpandableBuffer(final int buffersize) { super(); this.buffer = ByteBuffer.allocate(buffersize); this.mode = INPUT_MODE; } /** * Returns the current mode: *
* {@link #INPUT_MODE}: the buffer is in the input mode. *
* {@link #OUTPUT_MODE}: the buffer is in the output mode. * * @return current input/output mode. */ public int mode() { return this.mode; } public ByteBuffer buffer() { return this.buffer; } /** * Sets output mode. The buffer can now be read from. */ protected void setOutputMode() { if (this.mode != OUTPUT_MODE) { this.buffer.flip(); this.mode = OUTPUT_MODE; } } /** * Sets input mode. The buffer can now be written into. */ protected void setInputMode() { if (this.mode != INPUT_MODE) { if (this.buffer.hasRemaining()) { this.buffer.compact(); } else { this.buffer.clear(); } this.mode = INPUT_MODE; } } private void expandCapacity(final int capacity) { final ByteBuffer oldbuffer = this.buffer; this.buffer = ByteBuffer.allocate(capacity); oldbuffer.flip(); this.buffer.put(oldbuffer); } /** * Expands buffer's capacity. */ protected void expand() { int newcapacity = (this.buffer.capacity() + 1) << 1; if (newcapacity < 0) { newcapacity = Integer.MAX_VALUE; } expandCapacity(newcapacity); } /** * Ensures the buffer can accommodate the required capacity. */ protected void ensureCapacity(final int requiredCapacity) { if (requiredCapacity > this.buffer.capacity()) { expandCapacity(requiredCapacity); } } /** * Determines if the buffer contains data. * * @return {@code true} if there is data in the buffer, * {@code false} otherwise. */ public boolean hasData() { setOutputMode(); return this.buffer.hasRemaining(); } /** * Returns the length of this buffer. * * @return buffer length. */ public int length() { setOutputMode(); return this.buffer.remaining(); } /** * Returns available capacity of this buffer. * * @return buffer length. */ public int capacity() { setInputMode(); return this.buffer.remaining(); } /** * Clears buffer. */ protected void clear() { this.buffer.clear(); this.mode = INPUT_MODE; } @Override public String toString() { final StringBuilder sb = new StringBuilder(); sb.append("[mode="); if (mode() == INPUT_MODE) { sb.append("in"); } else { sb.append("out"); } sb.append(" pos="); sb.append(this.buffer.position()); sb.append(" lim="); sb.append(this.buffer.limit()); sb.append(" cap="); sb.append(this.buffer.capacity()); sb.append("]"); return sb.toString(); } }