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Snappy-Java Source Code
Snappy-Java is a Java port of the "snappy", a fast C++ compresser/decompresser developed by Google.
Snappy-Java Source Code files are provided in the source packge (snappy-java-1.1.8.4-sources.jar). You can download it at Snappy Maven Website.
You can also browse Snappy-Java Source Code below:
✍: FYIcenter.com
⏎ org/xerial/snappy/SnappyOutputStream.java
/*-------------------------------------------------------------------------- * Copyright 2011 Taro L. Saito * * 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. *--------------------------------------------------------------------------*/ //-------------------------------------- // XerialJ // // SnappyOutputStream.java // Since: 2011/03/31 17:44:10 // // $URL$ // $Author$ //-------------------------------------- package org.xerial.snappy; import org.xerial.snappy.buffer.BufferAllocatorFactory; import org.xerial.snappy.buffer.BufferAllocator; import org.xerial.snappy.buffer.CachedBufferAllocator; import java.io.IOException; import java.io.OutputStream; /** * This class implements a stream filter for writing compressed data using * Snappy. * <p> * The input data is blocked into 32kb size (in default), and each block is * compressed and then passed to the given {@link OutputStream}. * </p> * The output data format is: * <ol> * <li>snappy codec header defined in {@link SnappyCodec} (8 bytes) * <li>codec version (4 bytes integer, at least 1) and compatible version (4 bytes integer) * <li>compressed block 1 : a pair of (compressed data size [4 byte integer. * Big-endian], compressed data...) * <li>compressed block 2 * <li>... * </ol> * <p/> * Note that the compressed data created by {@link SnappyOutputStream} cannot be * uncompressed by {@link Snappy#uncompress(byte[])} since the output formats of * {@link Snappy#compress(byte[])} and {@link SnappyOutputStream} are different. * Use {@link SnappyInputStream} for uncompress the data generated by * {@link SnappyOutputStream}. * * @author leo */ public class SnappyOutputStream extends OutputStream { static final int MIN_BLOCK_SIZE = 1 * 1024; static final int DEFAULT_BLOCK_SIZE = 32 * 1024; // Use 32kb for the default block size protected final OutputStream out; private final int blockSize; private final BufferAllocator inputBufferAllocator; private final BufferAllocator outputBufferAllocator; // The input and output buffer fields are set to null when closing this stream: protected byte[] inputBuffer; protected byte[] outputBuffer; private int inputCursor = 0; private int outputCursor = 0; private boolean headerWritten; private boolean closed; public SnappyOutputStream(OutputStream out) { this(out, DEFAULT_BLOCK_SIZE); } /** * @param out * @param blockSize byte size of the internal buffer size * @throws IOException */ public SnappyOutputStream(OutputStream out, int blockSize) { this(out, blockSize, CachedBufferAllocator.getBufferAllocatorFactory()); } public SnappyOutputStream(OutputStream out, int blockSize, BufferAllocatorFactory bufferAllocatorFactory) { this.out = out; this.blockSize = Math.max(MIN_BLOCK_SIZE, blockSize); int inputSize = blockSize; int outputSize = SnappyCodec.HEADER_SIZE + 4 + Snappy.maxCompressedLength(blockSize); this.inputBufferAllocator = bufferAllocatorFactory.getBufferAllocator(inputSize); this.outputBufferAllocator = bufferAllocatorFactory.getBufferAllocator(outputSize); inputBuffer = inputBufferAllocator.allocate(inputSize); outputBuffer = outputBufferAllocator.allocate(outputSize); } /* (non-Javadoc) * @see java.io.OutputStream#write(byte[], int, int) */ @Override public void write(byte[] b, int byteOffset, int byteLength) throws IOException { if (closed) { throw new IOException("Stream is closed"); } int cursor = 0; while (cursor < byteLength) { int readLen = Math.min(byteLength - cursor, blockSize - inputCursor); // copy the input data to uncompressed buffer if (readLen > 0) { System.arraycopy(b, byteOffset + cursor, inputBuffer, inputCursor, readLen); inputCursor += readLen; } if (inputCursor < blockSize) { return; } compressInput(); cursor += readLen; } } /** * Compress the input long array data * * @param d input array * @param off offset in the array * @param len the number of elements in the array to copy * @throws IOException */ public void write(long[] d, int off, int len) throws IOException { rawWrite(d, off * 8, len * 8); } /** * Compress the input double array data * * @param f input array * @param off offset in the array * @param len the number of elements in the array to copy * @throws IOException */ public void write(double[] f, int off, int len) throws IOException { rawWrite(f, off * 8, len * 8); } /** * Compress the input float array data * * @param f input array * @param off offset in the array * @param len the number of elements in the array to copy * @throws IOException */ public void write(float[] f, int off, int len) throws IOException { rawWrite(f, off * 4, len * 4); } /** * Compress the input int array data * * @param f input array * @param off offset in the array * @param len the number of elements in the array to copy * @throws IOException */ public void write(int[] f, int off, int len) throws IOException { rawWrite(f, off * 4, len * 4); } /** * Compress the input short array data * * @param f input array * @param off offset in the array * @param len the number of elements in the array to copy * @throws IOException */ public void write(short[] f, int off, int len) throws IOException { rawWrite(f, off * 2, len * 2); } /** * Compress the input array data * * @param d * @throws IOException */ public void write(long[] d) throws IOException { write(d, 0, d.length); } /** * Compress the input array data * * @param f * @throws IOException */ public void write(double[] f) throws IOException { write(f, 0, f.length); } /** * Compress the input array data * * @param f * @throws IOException */ public void write(float[] f) throws IOException { write(f, 0, f.length); } /** * Compress the input array data * * @param f * @throws IOException */ public void write(int[] f) throws IOException { write(f, 0, f.length); } /** * Compress the input array data * * @param f * @throws IOException */ public void write(short[] f) throws IOException { write(f, 0, f.length); } private boolean hasSufficientOutputBufferFor(int inputSize) { int maxCompressedSize = Snappy.maxCompressedLength(inputSize); return maxCompressedSize < outputBuffer.length - outputCursor - 4; } /** * Compress the raw byte array data. * * @param array array data of any type (e.g., byte[], float[], long[], ...) * @param byteOffset * @param byteLength * @throws IOException */ public void rawWrite(Object array, int byteOffset, int byteLength) throws IOException { if (closed) { throw new IOException("Stream is closed"); } int cursor = 0; while (cursor < byteLength) { int readLen = Math.min(byteLength - cursor, blockSize - inputCursor); // copy the input data to uncompressed buffer if (readLen > 0) { Snappy.arrayCopy(array, byteOffset + cursor, readLen, inputBuffer, inputCursor); inputCursor += readLen; } if (inputCursor < blockSize) { return; } compressInput(); cursor += readLen; } } /** * Writes the specified byte to this output stream. The general contract for * write is that one byte is written to the output stream. The byte to be * written is the eight low-order bits of the argument b. The 24 high-order * bits of b are ignored. */ /* (non-Javadoc) * @see java.io.OutputStream#write(int) */ @Override public void write(int b) throws IOException { if (closed) { throw new IOException("Stream is closed"); } if (inputCursor >= inputBuffer.length) { compressInput(); } inputBuffer[inputCursor++] = (byte) b; } /* (non-Javadoc) * @see java.io.OutputStream#flush() */ @Override public void flush() throws IOException { if (closed) { throw new IOException("Stream is closed"); } compressInput(); dumpOutput(); out.flush(); } static void writeInt(byte[] dst, int offset, int v) { dst[offset] = (byte) ((v >> 24) & 0xFF); dst[offset + 1] = (byte) ((v >> 16) & 0xFF); dst[offset + 2] = (byte) ((v >> 8) & 0xFF); dst[offset + 3] = (byte) ((v >> 0) & 0xFF); } static int readInt(byte[] buffer, int pos) { int b1 = (buffer[pos] & 0xFF) << 24; int b2 = (buffer[pos + 1] & 0xFF) << 16; int b3 = (buffer[pos + 2] & 0xFF) << 8; int b4 = buffer[pos + 3] & 0xFF; return b1 | b2 | b3 | b4; } protected void dumpOutput() throws IOException { if (outputCursor > 0) { out.write(outputBuffer, 0, outputCursor); outputCursor = 0; } } protected void compressInput() throws IOException { if (!headerWritten) { outputCursor = writeHeader(); headerWritten = true; } if (inputCursor <= 0) { return; // no need to dump } // Compress and dump the buffer content if (!hasSufficientOutputBufferFor(inputCursor)) { dumpOutput(); } writeBlockPreemble(); int compressedSize = Snappy.compress(inputBuffer, 0, inputCursor, outputBuffer, outputCursor + 4); // Write compressed data size writeInt(outputBuffer, outputCursor, compressedSize); outputCursor += 4 + compressedSize; inputCursor = 0; } protected int writeHeader(){ return SnappyCodec.currentHeader.writeHeader(outputBuffer, 0); } /** * Optionally write a preemble before a block. Hadoop requires the actual block data size being written. This base * implementation does nothing. Derive implementation can call {@code writeCurrentDataSize()}. */ protected void writeBlockPreemble() { // do nothing } protected void writeCurrentDataSize(){ writeInt(outputBuffer, outputCursor, inputCursor); outputCursor += 4; } /** * close the stream */ /* (non-Javadoc) * @see java.io.OutputStream#close() */ @Override public void close() throws IOException { if (closed) { return; } try { flush(); out.close(); } finally { closed = true; inputBufferAllocator.release(inputBuffer); outputBufferAllocator.release(outputBuffer); inputBuffer = null; outputBuffer = null; } } }
⏎ org/xerial/snappy/SnappyOutputStream.java
Or download all of them as a single archive file:
File name: snappy-java-1.1.8.4-sources.jar File size: 1962098 bytes Release date: 2021-01-25 Download
⇒ Download and Install Snappy-Java Binary Package
2021-07-13, 18960👍, 0💬
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