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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/SnappyInputStream.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 // // SnappyInputStream.java // Since: 2011/03/31 20:14:56 // // $URL$ // $Author$ //-------------------------------------- package org.xerial.snappy; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; /** * A stream filter for reading data compressed by {@link SnappyOutputStream}. * * @author leo */ public class SnappyInputStream extends InputStream { private boolean finishedReading = false; protected final InputStream in; private byte[] compressed; private byte[] uncompressed; private int uncompressedCursor = 0; private int uncompressedLimit = 0; private byte[] header = new byte[SnappyCodec.headerSize()]; /** * Create a filter for reading compressed data as a uncompressed stream * * @param input * @throws IOException */ public SnappyInputStream(InputStream input) throws IOException { this.in = input; readHeader(); } /** * Close the stream */ /* (non-Javadoc) * @see java.io.InputStream#close() */ @Override public void close() throws IOException { compressed = null; uncompressed = null; if (in != null) { in.close(); } } protected void readHeader() throws IOException { int readBytes = 0; while (readBytes < header.length) { int ret = in.read(header, readBytes, header.length - readBytes); if (ret == -1) { break; } readBytes += ret; } // Quick test of the header if (readBytes == 0) { // Snappy produces at least 1-byte result. So the empty input is not a valid input throw new SnappyIOException(SnappyErrorCode.EMPTY_INPUT, "Cannot decompress empty stream"); } if (readBytes < header.length || !SnappyCodec.hasMagicHeaderPrefix(header)) { // do the default uncompression // (probably) compressed by Snappy.compress(byte[]) readFully(header, readBytes); return; } } private static boolean isValidHeader(byte[] header) throws IOException { SnappyCodec codec = SnappyCodec.readHeader(new ByteArrayInputStream(header)); if (codec.isValidMagicHeader()) { // The input data is compressed by SnappyOutputStream if (codec.version < SnappyCodec.MINIMUM_COMPATIBLE_VERSION) { throw new SnappyIOException(SnappyErrorCode.INCOMPATIBLE_VERSION, String.format( "Compressed with an incompatible codec version %d. At least version %d is required", codec.version, SnappyCodec.MINIMUM_COMPATIBLE_VERSION)); } return true; } else { return false; } } protected void readFully(byte[] fragment, int fragmentLength) throws IOException { if (fragmentLength == 0) { finishedReading = true; return; } // read the entire input data to the buffer compressed = new byte[Math.max(8 * 1024, fragmentLength)]; // 8K System.arraycopy(fragment, 0, compressed, 0, fragmentLength); int cursor = fragmentLength; for (int readBytes = 0; (readBytes = in.read(compressed, cursor, compressed.length - cursor)) != -1; ) { cursor += readBytes; if (cursor >= compressed.length) { byte[] newBuf = new byte[(compressed.length * 2)]; System.arraycopy(compressed, 0, newBuf, 0, compressed.length); compressed = newBuf; } } finishedReading = true; // Uncompress int uncompressedLength = Snappy.uncompressedLength(compressed, 0, cursor); uncompressed = new byte[uncompressedLength]; Snappy.uncompress(compressed, 0, cursor, uncompressed, 0); this.uncompressedCursor = 0; this.uncompressedLimit = uncompressedLength; } /** * Reads up to len bytes of data from the input stream into an array of * bytes. */ /* (non-Javadoc) * @see java.io.InputStream#read(byte[], int, int) */ @Override public int read(byte[] b, int byteOffset, int byteLength) throws IOException { int writtenBytes = 0; for (; writtenBytes < byteLength; ) { if (uncompressedCursor >= uncompressedLimit) { if (hasNextChunk()) { continue; } else { return writtenBytes == 0 ? -1 : writtenBytes; } } int bytesToWrite = Math.min(uncompressedLimit - uncompressedCursor, byteLength - writtenBytes); System.arraycopy(uncompressed, uncompressedCursor, b, byteOffset + writtenBytes, bytesToWrite); writtenBytes += bytesToWrite; uncompressedCursor += bytesToWrite; } return writtenBytes; } /** * Read uncompressed data into the specified array * * @param array * @param byteOffset * @param byteLength * @return written bytes * @throws IOException */ public int rawRead(Object array, int byteOffset, int byteLength) throws IOException { int writtenBytes = 0; for (; writtenBytes < byteLength; ) { if (uncompressedCursor >= uncompressedLimit) { if (hasNextChunk()) { continue; } else { return writtenBytes == 0 ? -1 : writtenBytes; } } int bytesToWrite = Math.min(uncompressedLimit - uncompressedCursor, byteLength - writtenBytes); Snappy.arrayCopy(uncompressed, uncompressedCursor, bytesToWrite, array, byteOffset + writtenBytes); writtenBytes += bytesToWrite; uncompressedCursor += bytesToWrite; } return writtenBytes; } /** * Read long array from the stream * * @param d input * @param off offset * @param len the number of long elements to read * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(long[] d, int off, int len) throws IOException { return rawRead(d, off * 8, len * 8); } /** * Read long array from the stream * * @param d * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(long[] d) throws IOException { return read(d, 0, d.length); } /** * Read double array from the stream * * @param d input * @param off offset * @param len the number of double elements to read * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(double[] d, int off, int len) throws IOException { return rawRead(d, off * 8, len * 8); } /** * Read double array from the stream * * @param d * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(double[] d) throws IOException { return read(d, 0, d.length); } /** * Read int array from the stream * * @param d * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(int[] d) throws IOException { return read(d, 0, d.length); } /** * Read int array from the stream * * @param d input * @param off offset * @param len the number of int elements to read * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(int[] d, int off, int len) throws IOException { return rawRead(d, off * 4, len * 4); } /** * Read float array from the stream * * @param d input * @param off offset * @param len the number of float elements to read * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(float[] d, int off, int len) throws IOException { return rawRead(d, off * 4, len * 4); } /** * Read float array from the stream * * @param d * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(float[] d) throws IOException { return read(d, 0, d.length); } /** * Read short array from the stream * * @param d input * @param off offset * @param len the number of short elements to read * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(short[] d, int off, int len) throws IOException { return rawRead(d, off * 2, len * 2); } /** * Read short array from the stream * * @param d * @return the total number of bytes read into the buffer, or -1 if there is * no more data because the end of the stream has been reached. * @throws IOException */ public int read(short[] d) throws IOException { return read(d, 0, d.length); } /** * Read next len bytes * * @param dest * @param offset * @param len * @return read bytes */ private int readNext(byte[] dest, int offset, int len) throws IOException { int readBytes = 0; while (readBytes < len) { int ret = in.read(dest, readBytes + offset, len - readBytes); if (ret == -1) { finishedReading = true; return readBytes; } readBytes += ret; } return readBytes; } protected boolean hasNextChunk() throws IOException { if (finishedReading) { return false; } uncompressedCursor = 0; uncompressedLimit = 0; int readBytes = readNext(header, 0, 4); if (readBytes < 4) { return false; } int chunkSize = SnappyOutputStream.readInt(header, 0); if (chunkSize == SnappyCodec.MAGIC_HEADER_HEAD) { // Concatenated data int remainingHeaderSize = SnappyCodec.headerSize() - 4; readBytes = readNext(header, 4, remainingHeaderSize); if(readBytes < remainingHeaderSize) { throw new SnappyIOException(SnappyErrorCode.FAILED_TO_UNCOMPRESS, String.format("Insufficient header size in a concatenated block")); } if (isValidHeader(header)) { return hasNextChunk(); } else { return false; } } // extend the compressed data buffer size if (compressed == null || chunkSize > compressed.length) { compressed = new byte[chunkSize]; } readBytes = 0; while (readBytes < chunkSize) { int ret = in.read(compressed, readBytes, chunkSize - readBytes); if (ret == -1) { break; } readBytes += ret; } if (readBytes < chunkSize) { throw new IOException("failed to read chunk"); } int uncompressedLength = Snappy.uncompressedLength(compressed, 0, chunkSize); if (uncompressed == null || uncompressedLength > uncompressed.length) { uncompressed = new byte[uncompressedLength]; } int actualUncompressedLength = Snappy.uncompress(compressed, 0, chunkSize, uncompressed, 0); if (uncompressedLength != actualUncompressedLength) { throw new SnappyIOException(SnappyErrorCode.INVALID_CHUNK_SIZE, String.format("expected %,d bytes, but decompressed chunk has %,d bytes", uncompressedLength, actualUncompressedLength)); } uncompressedLimit = actualUncompressedLength; return true; } /** * Reads the next byte of uncompressed data from the input stream. The value * byte is returned as an int in the range 0 to 255. If no byte is available * because the end of the stream has been reached, the value -1 is returned. * This method blocks until input data is available, the end of the stream * is detected, or an exception is thrown. */ /* (non-Javadoc) * @see java.io.InputStream#read() */ @Override public int read() throws IOException { if (uncompressedCursor < uncompressedLimit) { return uncompressed[uncompressedCursor++] & 0xFF; } else { if (hasNextChunk()) { return read(); } else { return -1; } } } /* (non-Javadoc) * @see java.io.InputStream#available() */ @Override public int available() throws IOException { if (uncompressedCursor < uncompressedLimit) { return uncompressedLimit - uncompressedCursor; } else { if (hasNextChunk()) { return uncompressedLimit - uncompressedCursor; } else { return 0; } } } }
⏎ org/xerial/snappy/SnappyInputStream.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, 18966👍, 0💬
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