149 lines
5.1 KiB
Java
149 lines
5.1 KiB
Java
// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
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// Licensed under the MIT License:
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package org.capnproto;
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import java.io.IOException;
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import java.nio.channels.ReadableByteChannel;
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import java.nio.ByteBuffer;
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public final class PackedInputStream implements ReadableByteChannel {
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final BufferedInputStream inner;
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public PackedInputStream(BufferedInputStream input) {
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this.inner = input;
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}
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public int read(ByteBuffer outBuf) throws IOException {
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int len = outBuf.remaining();
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if (len == 0) { return 0; }
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if (len % 8 != 0) {
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throw new DecodeException("PackedInputStream reads must be word-aligned");
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}
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int outPtr = outBuf.position();
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int outEnd = outPtr + len;
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ByteBuffer inBuf = this.inner.getReadBuffer();
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while (true) {
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byte tag = 0;
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if (inBuf.remaining() < 10) {
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if (outBuf.remaining() == 0) {
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return len;
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}
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if (inBuf.remaining() == 0) {
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inBuf = this.inner.getReadBuffer();
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continue;
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}
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//# We have at least 1, but not 10, bytes available. We need to read
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//# slowly, doing a bounds check on each byte.
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tag = inBuf.get();
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for (int i = 0; i < 8; ++i) {
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if ((tag & (1 << i)) != 0) {
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if (inBuf.remaining() == 0) {
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inBuf = this.inner.getReadBuffer();
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}
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outBuf.put(inBuf.get());
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} else {
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outBuf.put((byte)0);
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}
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}
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if (inBuf.remaining() == 0 && (tag == 0 || tag == (byte)0xff)) {
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inBuf = this.inner.getReadBuffer();
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}
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} else {
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tag = inBuf.get();
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for (int n = 0; n < 8; ++n) {
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boolean isNonzero = (tag & (1 << n)) != 0;
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outBuf.put((byte)(inBuf.get() & (isNonzero ? -1 : 0)));
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inBuf.position(inBuf.position() + (isNonzero ? 0 : -1));
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}
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}
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if (tag == 0) {
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if (inBuf.remaining() == 0) {
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throw new DecodeException("Should always have non-empty buffer here.");
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}
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int runLength = (0xff & (int)inBuf.get()) * 8;
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if (runLength > outEnd - outPtr) {
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throw new DecodeException("Packed input did not end cleanly on a segment boundary");
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}
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for (int i = 0; i < runLength; ++i) {
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outBuf.put((byte) 0);
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}
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} else if (tag == (byte)0xff) {
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int runLength = (0xff & (int)inBuf.get()) * 8;
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if (inBuf.remaining() >= runLength) {
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//# Fast path.
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ByteBuffer slice = inBuf.slice();
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slice.limit(runLength);
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outBuf.put(slice);
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inBuf.position(inBuf.position() + runLength);
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} else {
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//# Copy over the first buffer, then do one big read for the rest.
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runLength -= inBuf.remaining();
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outBuf.put(inBuf);
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ByteBuffer slice = outBuf.slice();
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slice.limit(runLength);
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this.inner.read(slice);
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outBuf.position(outBuf.position() + runLength);
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if (outBuf.remaining() == 0) {
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return len;
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} else {
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inBuf = this.inner.getReadBuffer();
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continue;
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}
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}
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}
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if (outBuf.remaining() == 0) {
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return len;
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}
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}
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}
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public void close() throws IOException {
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inner.close();
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}
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public boolean isOpen() {
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return inner.isOpen();
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}
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}
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