| /* |
| * 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.lucene.codecs; |
| |
| |
| import java.io.IOException; |
| import java.nio.charset.StandardCharsets; |
| import java.util.Arrays; |
| |
| import org.apache.lucene.index.CorruptIndexException; |
| import org.apache.lucene.index.IndexFormatTooNewException; |
| import org.apache.lucene.index.IndexFormatTooOldException; |
| import org.apache.lucene.store.BufferedChecksumIndexInput; |
| import org.apache.lucene.store.ChecksumIndexInput; |
| import org.apache.lucene.store.DataInput; |
| import org.apache.lucene.store.DataOutput; |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.store.IndexOutput; |
| import org.apache.lucene.util.BytesRef; |
| import org.apache.lucene.util.IOUtils; |
| import org.apache.lucene.util.StringHelper; |
| |
| /** |
| * Utility class for reading and writing versioned headers. |
| * <p> |
| * Writing codec headers is useful to ensure that a file is in |
| * the format you think it is. |
| * |
| * @lucene.experimental |
| */ |
| |
| public final class CodecUtil { |
| private CodecUtil() {} // no instance |
| |
| /** |
| * Constant to identify the start of a codec header. |
| */ |
| public final static int CODEC_MAGIC = 0x3fd76c17; |
| /** |
| * Constant to identify the start of a codec footer. |
| */ |
| public final static int FOOTER_MAGIC = ~CODEC_MAGIC; |
| |
| /** |
| * Writes a codec header, which records both a string to |
| * identify the file and a version number. This header can |
| * be parsed and validated with |
| * {@link #checkHeader(DataInput, String, int, int) checkHeader()}. |
| * <p> |
| * CodecHeader --> Magic,CodecName,Version |
| * <ul> |
| * <li>Magic --> {@link DataOutput#writeInt Uint32}. This |
| * identifies the start of the header. It is always {@value #CODEC_MAGIC}. |
| * <li>CodecName --> {@link DataOutput#writeString String}. This |
| * is a string to identify this file. |
| * <li>Version --> {@link DataOutput#writeInt Uint32}. Records |
| * the version of the file. |
| * </ul> |
| * <p> |
| * Note that the length of a codec header depends only upon the |
| * name of the codec, so this length can be computed at any time |
| * with {@link #headerLength(String)}. |
| * |
| * @param out Output stream |
| * @param codec String to identify this file. It should be simple ASCII, |
| * less than 128 characters in length. |
| * @param version Version number |
| * @throws IOException If there is an I/O error writing to the underlying medium. |
| * @throws IllegalArgumentException If the codec name is not simple ASCII, or is more than 127 characters in length |
| */ |
| public static void writeHeader(DataOutput out, String codec, int version) throws IOException { |
| BytesRef bytes = new BytesRef(codec); |
| if (bytes.length != codec.length() || bytes.length >= 128) { |
| throw new IllegalArgumentException("codec must be simple ASCII, less than 128 characters in length [got " + codec + "]"); |
| } |
| out.writeInt(CODEC_MAGIC); |
| out.writeString(codec); |
| out.writeInt(version); |
| } |
| |
| /** |
| * Writes a codec header for an index file, which records both a string to |
| * identify the format of the file, a version number, and data to identify |
| * the file instance (ID and auxiliary suffix such as generation). |
| * <p> |
| * This header can be parsed and validated with |
| * {@link #checkIndexHeader(DataInput, String, int, int, byte[], String) checkIndexHeader()}. |
| * <p> |
| * IndexHeader --> CodecHeader,ObjectID,ObjectSuffix |
| * <ul> |
| * <li>CodecHeader --> {@link #writeHeader} |
| * <li>ObjectID --> {@link DataOutput#writeByte byte}<sup>16</sup> |
| * <li>ObjectSuffix --> SuffixLength,SuffixBytes |
| * <li>SuffixLength --> {@link DataOutput#writeByte byte} |
| * <li>SuffixBytes --> {@link DataOutput#writeByte byte}<sup>SuffixLength</sup> |
| * </ul> |
| * <p> |
| * Note that the length of an index header depends only upon the |
| * name of the codec and suffix, so this length can be computed at any time |
| * with {@link #indexHeaderLength(String,String)}. |
| * |
| * @param out Output stream |
| * @param codec String to identify the format of this file. It should be simple ASCII, |
| * less than 128 characters in length. |
| * @param id Unique identifier for this particular file instance. |
| * @param suffix auxiliary suffix information for the file. It should be simple ASCII, |
| * less than 256 characters in length. |
| * @param version Version number |
| * @throws IOException If there is an I/O error writing to the underlying medium. |
| * @throws IllegalArgumentException If the codec name is not simple ASCII, or |
| * is more than 127 characters in length, or if id is invalid, |
| * or if the suffix is not simple ASCII, or more than 255 characters |
| * in length. |
| */ |
| public static void writeIndexHeader(DataOutput out, String codec, int version, byte[] id, String suffix) throws IOException { |
| if (id.length != StringHelper.ID_LENGTH) { |
| throw new IllegalArgumentException("Invalid id: " + StringHelper.idToString(id)); |
| } |
| writeHeader(out, codec, version); |
| out.writeBytes(id, 0, id.length); |
| BytesRef suffixBytes = new BytesRef(suffix); |
| if (suffixBytes.length != suffix.length() || suffixBytes.length >= 256) { |
| throw new IllegalArgumentException("suffix must be simple ASCII, less than 256 characters in length [got " + suffix + "]"); |
| } |
| out.writeByte((byte) suffixBytes.length); |
| out.writeBytes(suffixBytes.bytes, suffixBytes.offset, suffixBytes.length); |
| } |
| |
| /** |
| * Computes the length of a codec header. |
| * |
| * @param codec Codec name. |
| * @return length of the entire codec header. |
| * @see #writeHeader(DataOutput, String, int) |
| */ |
| public static int headerLength(String codec) { |
| return 9+codec.length(); |
| } |
| |
| /** |
| * Computes the length of an index header. |
| * |
| * @param codec Codec name. |
| * @return length of the entire index header. |
| * @see #writeIndexHeader(DataOutput, String, int, byte[], String) |
| */ |
| public static int indexHeaderLength(String codec, String suffix) { |
| return headerLength(codec) + StringHelper.ID_LENGTH + 1 + suffix.length(); |
| } |
| |
| /** |
| * Reads and validates a header previously written with |
| * {@link #writeHeader(DataOutput, String, int)}. |
| * <p> |
| * When reading a file, supply the expected <code>codec</code> and |
| * an expected version range (<code>minVersion to maxVersion</code>). |
| * |
| * @param in Input stream, positioned at the point where the |
| * header was previously written. Typically this is located |
| * at the beginning of the file. |
| * @param codec The expected codec name. |
| * @param minVersion The minimum supported expected version number. |
| * @param maxVersion The maximum supported expected version number. |
| * @return The actual version found, when a valid header is found |
| * that matches <code>codec</code>, with an actual version |
| * where {@code minVersion <= actual <= maxVersion}. |
| * Otherwise an exception is thrown. |
| * @throws CorruptIndexException If the first four bytes are not |
| * {@link #CODEC_MAGIC}, or if the actual codec found is |
| * not <code>codec</code>. |
| * @throws IndexFormatTooOldException If the actual version is less |
| * than <code>minVersion</code>. |
| * @throws IndexFormatTooNewException If the actual version is greater |
| * than <code>maxVersion</code>. |
| * @throws IOException If there is an I/O error reading from the underlying medium. |
| * @see #writeHeader(DataOutput, String, int) |
| */ |
| public static int checkHeader(DataInput in, String codec, int minVersion, int maxVersion) throws IOException { |
| // Safety to guard against reading a bogus string: |
| final int actualHeader = in.readInt(); |
| if (actualHeader != CODEC_MAGIC) { |
| throw new CorruptIndexException("codec header mismatch: actual header=" + actualHeader + " vs expected header=" + CODEC_MAGIC, in); |
| } |
| return checkHeaderNoMagic(in, codec, minVersion, maxVersion); |
| } |
| |
| /** Like {@link |
| * #checkHeader(DataInput,String,int,int)} except this |
| * version assumes the first int has already been read |
| * and validated from the input. */ |
| public static int checkHeaderNoMagic(DataInput in, String codec, int minVersion, int maxVersion) throws IOException { |
| final String actualCodec = in.readString(); |
| if (!actualCodec.equals(codec)) { |
| throw new CorruptIndexException("codec mismatch: actual codec=" + actualCodec + " vs expected codec=" + codec, in); |
| } |
| |
| final int actualVersion = in.readInt(); |
| if (actualVersion < minVersion) { |
| throw new IndexFormatTooOldException(in, actualVersion, minVersion, maxVersion); |
| } |
| if (actualVersion > maxVersion) { |
| throw new IndexFormatTooNewException(in, actualVersion, minVersion, maxVersion); |
| } |
| |
| return actualVersion; |
| } |
| |
| /** |
| * Reads and validates a header previously written with |
| * {@link #writeIndexHeader(DataOutput, String, int, byte[], String)}. |
| * <p> |
| * When reading a file, supply the expected <code>codec</code>, |
| * expected version range (<code>minVersion to maxVersion</code>), |
| * and object ID and suffix. |
| * |
| * @param in Input stream, positioned at the point where the |
| * header was previously written. Typically this is located |
| * at the beginning of the file. |
| * @param codec The expected codec name. |
| * @param minVersion The minimum supported expected version number. |
| * @param maxVersion The maximum supported expected version number. |
| * @param expectedID The expected object identifier for this file. |
| * @param expectedSuffix The expected auxiliary suffix for this file. |
| * @return The actual version found, when a valid header is found |
| * that matches <code>codec</code>, with an actual version |
| * where {@code minVersion <= actual <= maxVersion}, |
| * and matching <code>expectedID</code> and <code>expectedSuffix</code> |
| * Otherwise an exception is thrown. |
| * @throws CorruptIndexException If the first four bytes are not |
| * {@link #CODEC_MAGIC}, or if the actual codec found is |
| * not <code>codec</code>, or if the <code>expectedID</code> |
| * or <code>expectedSuffix</code> do not match. |
| * @throws IndexFormatTooOldException If the actual version is less |
| * than <code>minVersion</code>. |
| * @throws IndexFormatTooNewException If the actual version is greater |
| * than <code>maxVersion</code>. |
| * @throws IOException If there is an I/O error reading from the underlying medium. |
| * @see #writeIndexHeader(DataOutput, String, int, byte[],String) |
| */ |
| public static int checkIndexHeader(DataInput in, String codec, int minVersion, int maxVersion, byte[] expectedID, String expectedSuffix) throws IOException { |
| int version = checkHeader(in, codec, minVersion, maxVersion); |
| checkIndexHeaderID(in, expectedID); |
| checkIndexHeaderSuffix(in, expectedSuffix); |
| return version; |
| } |
| |
| /** |
| * Expert: verifies the incoming {@link IndexInput} has an index header |
| * and that its segment ID matches the expected one, and then copies |
| * that index header into the provided {@link DataOutput}. This is |
| * useful when building compound files. |
| * |
| * @param in Input stream, positioned at the point where the |
| * index header was previously written. Typically this is located |
| * at the beginning of the file. |
| * @param out Output stream, where the header will be copied to. |
| * @param expectedID Expected segment ID |
| * @throws CorruptIndexException If the first four bytes are not |
| * {@link #CODEC_MAGIC}, or if the <code>expectedID</code> |
| * does not match. |
| * @throws IOException If there is an I/O error reading from the underlying medium. |
| * |
| * @lucene.internal |
| */ |
| public static void verifyAndCopyIndexHeader(IndexInput in, DataOutput out, byte[] expectedID) throws IOException { |
| // make sure it's large enough to have a header and footer |
| if (in.length() < footerLength() + headerLength("")) { |
| throw new CorruptIndexException("compound sub-files must have a valid codec header and footer: file is too small (" + in.length() + " bytes)", in); |
| } |
| |
| int actualHeader = in.readInt(); |
| if (actualHeader != CODEC_MAGIC) { |
| throw new CorruptIndexException("compound sub-files must have a valid codec header and footer: codec header mismatch: actual header=" + actualHeader + " vs expected header=" + CodecUtil.CODEC_MAGIC, in); |
| } |
| |
| // we can't verify these, so we pass-through: |
| String codec = in.readString(); |
| int version = in.readInt(); |
| |
| // verify id: |
| checkIndexHeaderID(in, expectedID); |
| |
| // we can't verify extension either, so we pass-through: |
| int suffixLength = in.readByte() & 0xFF; |
| byte[] suffixBytes = new byte[suffixLength]; |
| in.readBytes(suffixBytes, 0, suffixLength); |
| |
| // now write the header we just verified |
| out.writeInt(CodecUtil.CODEC_MAGIC); |
| out.writeString(codec); |
| out.writeInt(version); |
| out.writeBytes(expectedID, 0, expectedID.length); |
| out.writeByte((byte) suffixLength); |
| out.writeBytes(suffixBytes, 0, suffixLength); |
| } |
| |
| |
| /** Retrieves the full index header from the provided {@link IndexInput}. |
| * This throws {@link CorruptIndexException} if this file does |
| * not appear to be an index file. */ |
| public static byte[] readIndexHeader(IndexInput in) throws IOException { |
| in.seek(0); |
| final int actualHeader = in.readInt(); |
| if (actualHeader != CODEC_MAGIC) { |
| throw new CorruptIndexException("codec header mismatch: actual header=" + actualHeader + " vs expected header=" + CODEC_MAGIC, in); |
| } |
| String codec = in.readString(); |
| in.readInt(); |
| in.seek(in.getFilePointer() + StringHelper.ID_LENGTH); |
| int suffixLength = in.readByte() & 0xFF; |
| byte[] bytes = new byte[headerLength(codec) + StringHelper.ID_LENGTH + 1 + suffixLength]; |
| in.seek(0); |
| in.readBytes(bytes, 0, bytes.length); |
| return bytes; |
| } |
| |
| /** Retrieves the full footer from the provided {@link IndexInput}. This throws |
| * {@link CorruptIndexException} if this file does not have a valid footer. */ |
| public static byte[] readFooter(IndexInput in) throws IOException { |
| if (in.length() < footerLength()) { |
| throw new CorruptIndexException("misplaced codec footer (file truncated?): length=" + in.length() + " but footerLength==" + footerLength(), in); |
| } |
| in.seek(in.length() - footerLength()); |
| validateFooter(in); |
| in.seek(in.length() - footerLength()); |
| byte[] bytes = new byte[footerLength()]; |
| in.readBytes(bytes, 0, bytes.length); |
| return bytes; |
| } |
| |
| /** Expert: just reads and verifies the object ID of an index header */ |
| public static byte[] checkIndexHeaderID(DataInput in, byte[] expectedID) throws IOException { |
| byte id[] = new byte[StringHelper.ID_LENGTH]; |
| in.readBytes(id, 0, id.length); |
| if (!Arrays.equals(id, expectedID)) { |
| throw new CorruptIndexException("file mismatch, expected id=" + StringHelper.idToString(expectedID) |
| + ", got=" + StringHelper.idToString(id), in); |
| } |
| return id; |
| } |
| |
| /** Expert: just reads and verifies the suffix of an index header */ |
| public static String checkIndexHeaderSuffix(DataInput in, String expectedSuffix) throws IOException { |
| int suffixLength = in.readByte() & 0xFF; |
| byte suffixBytes[] = new byte[suffixLength]; |
| in.readBytes(suffixBytes, 0, suffixBytes.length); |
| String suffix = new String(suffixBytes, 0, suffixBytes.length, StandardCharsets.UTF_8); |
| if (!suffix.equals(expectedSuffix)) { |
| throw new CorruptIndexException("file mismatch, expected suffix=" + expectedSuffix |
| + ", got=" + suffix, in); |
| } |
| return suffix; |
| } |
| |
| /** |
| * Writes a codec footer, which records both a checksum |
| * algorithm ID and a checksum. This footer can |
| * be parsed and validated with |
| * {@link #checkFooter(ChecksumIndexInput) checkFooter()}. |
| * <p> |
| * CodecFooter --> Magic,AlgorithmID,Checksum |
| * <ul> |
| * <li>Magic --> {@link DataOutput#writeInt Uint32}. This |
| * identifies the start of the footer. It is always {@value #FOOTER_MAGIC}. |
| * <li>AlgorithmID --> {@link DataOutput#writeInt Uint32}. This |
| * indicates the checksum algorithm used. Currently this is always 0, |
| * for zlib-crc32. |
| * <li>Checksum --> {@link DataOutput#writeLong Uint64}. The |
| * actual checksum value for all previous bytes in the stream, including |
| * the bytes from Magic and AlgorithmID. |
| * </ul> |
| * |
| * @param out Output stream |
| * @throws IOException If there is an I/O error writing to the underlying medium. |
| */ |
| public static void writeFooter(IndexOutput out) throws IOException { |
| out.writeInt(FOOTER_MAGIC); |
| out.writeInt(0); |
| writeCRC(out); |
| } |
| |
| /** |
| * Computes the length of a codec footer. |
| * |
| * @return length of the entire codec footer. |
| * @see #writeFooter(IndexOutput) |
| */ |
| public static int footerLength() { |
| return 16; |
| } |
| |
| /** |
| * Validates the codec footer previously written by {@link #writeFooter}. |
| * @return actual checksum value |
| * @throws IOException if the footer is invalid, if the checksum does not match, |
| * or if {@code in} is not properly positioned before the footer |
| * at the end of the stream. |
| */ |
| public static long checkFooter(ChecksumIndexInput in) throws IOException { |
| validateFooter(in); |
| long actualChecksum = in.getChecksum(); |
| long expectedChecksum = readCRC(in); |
| if (expectedChecksum != actualChecksum) { |
| throw new CorruptIndexException("checksum failed (hardware problem?) : expected=" + Long.toHexString(expectedChecksum) + |
| " actual=" + Long.toHexString(actualChecksum), in); |
| } |
| return actualChecksum; |
| } |
| |
| /** |
| * Validates the codec footer previously written by {@link #writeFooter}, optionally |
| * passing an unexpected exception that has already occurred. |
| * <p> |
| * When a {@code priorException} is provided, this method will add a suppressed exception |
| * indicating whether the checksum for the stream passes, fails, or cannot be computed, and |
| * rethrow it. Otherwise it behaves the same as {@link #checkFooter(ChecksumIndexInput)}. |
| * <p> |
| * Example usage: |
| * <pre class="prettyprint"> |
| * try (ChecksumIndexInput input = ...) { |
| * Throwable priorE = null; |
| * try { |
| * // ... read a bunch of stuff ... |
| * } catch (Throwable exception) { |
| * priorE = exception; |
| * } finally { |
| * CodecUtil.checkFooter(input, priorE); |
| * } |
| * } |
| * </pre> |
| */ |
| public static void checkFooter(ChecksumIndexInput in, Throwable priorException) throws IOException { |
| if (priorException == null) { |
| checkFooter(in); |
| } else { |
| try { |
| // If we have evidence of corruption then we return the corruption as the |
| // main exception and the prior exception gets suppressed. Otherwise we |
| // return the prior exception with a suppressed exception that notifies |
| // the user that checksums matched. |
| long remaining = in.length() - in.getFilePointer(); |
| if (remaining < footerLength()) { |
| // corruption caused us to read into the checksum footer already: we can't proceed |
| throw new CorruptIndexException("checksum status indeterminate: remaining=" + remaining + |
| "; please run checkindex for more details", in); |
| } else { |
| // otherwise, skip any unread bytes. |
| in.skipBytes(remaining - footerLength()); |
| |
| // now check the footer |
| long checksum = checkFooter(in); |
| priorException.addSuppressed(new CorruptIndexException("checksum passed (" + Long.toHexString(checksum) + |
| "). possibly transient resource issue, or a Lucene or JVM bug", in)); |
| } |
| } catch (CorruptIndexException corruptException) { |
| corruptException.addSuppressed(priorException); |
| throw corruptException; |
| } catch (Throwable t) { |
| // catch-all for things that shouldn't go wrong (e.g. OOM during readInt) but could... |
| priorException.addSuppressed(new CorruptIndexException("checksum status indeterminate: unexpected exception", in, t)); |
| } |
| throw IOUtils.rethrowAlways(priorException); |
| } |
| } |
| |
| /** |
| * Returns (but does not validate) the checksum previously written by {@link #checkFooter}. |
| * @return actual checksum value |
| * @throws IOException if the footer is invalid |
| */ |
| public static long retrieveChecksum(IndexInput in) throws IOException { |
| if (in.length() < footerLength()) { |
| throw new CorruptIndexException("misplaced codec footer (file truncated?): length=" + in.length() + " but footerLength==" + footerLength(), in); |
| } |
| in.seek(in.length() - footerLength()); |
| validateFooter(in); |
| return readCRC(in); |
| } |
| |
| /** |
| * Returns (but does not validate) the checksum previously written by {@link #checkFooter}. |
| * @return actual checksum value |
| * @throws IOException if the footer is invalid |
| */ |
| public static long retrieveChecksum(IndexInput in, long expectedLength) throws IOException { |
| if (expectedLength < footerLength()) { |
| throw new IllegalArgumentException("expectedLength cannot be less than the footer length"); |
| } |
| if (in.length() < expectedLength) { |
| throw new CorruptIndexException("truncated file: length=" + in.length() + " but expectedLength==" + expectedLength, in); |
| } else if (in.length() > expectedLength) { |
| throw new CorruptIndexException("file too long: length=" + in.length() + " but expectedLength==" + expectedLength, in); |
| } |
| |
| return retrieveChecksum(in); |
| } |
| |
| private static void validateFooter(IndexInput in) throws IOException { |
| long remaining = in.length() - in.getFilePointer(); |
| long expected = footerLength(); |
| if (remaining < expected) { |
| throw new CorruptIndexException("misplaced codec footer (file truncated?): remaining=" + remaining + ", expected=" + expected + ", fp=" + in.getFilePointer(), in); |
| } else if (remaining > expected) { |
| throw new CorruptIndexException("misplaced codec footer (file extended?): remaining=" + remaining + ", expected=" + expected + ", fp=" + in.getFilePointer(), in); |
| } |
| |
| final int magic = in.readInt(); |
| if (magic != FOOTER_MAGIC) { |
| throw new CorruptIndexException("codec footer mismatch (file truncated?): actual footer=" + magic + " vs expected footer=" + FOOTER_MAGIC, in); |
| } |
| |
| final int algorithmID = in.readInt(); |
| if (algorithmID != 0) { |
| throw new CorruptIndexException("codec footer mismatch: unknown algorithmID: " + algorithmID, in); |
| } |
| } |
| |
| /** |
| * Clones the provided input, reads all bytes from the file, and calls {@link #checkFooter} |
| * <p> |
| * Note that this method may be slow, as it must process the entire file. |
| * If you just need to extract the checksum value, call {@link #retrieveChecksum}. |
| */ |
| public static long checksumEntireFile(IndexInput input) throws IOException { |
| IndexInput clone = input.clone(); |
| clone.seek(0); |
| ChecksumIndexInput in = new BufferedChecksumIndexInput(clone); |
| assert in.getFilePointer() == 0; |
| if (in.length() < footerLength()) { |
| throw new CorruptIndexException("misplaced codec footer (file truncated?): length=" + in.length() + " but footerLength==" + footerLength(), input); |
| } |
| in.seek(in.length() - footerLength()); |
| return checkFooter(in); |
| } |
| |
| /** |
| * Reads CRC32 value as a 64-bit long from the input. |
| * @throws CorruptIndexException if CRC is formatted incorrectly (wrong bits set) |
| * @throws IOException if an i/o error occurs |
| */ |
| static long readCRC(IndexInput input) throws IOException { |
| long value = input.readLong(); |
| if ((value & 0xFFFFFFFF00000000L) != 0) { |
| throw new CorruptIndexException("Illegal CRC-32 checksum: " + value, input); |
| } |
| return value; |
| } |
| |
| /** |
| * Writes CRC32 value as a 64-bit long to the output. |
| * @throws IllegalStateException if CRC is formatted incorrectly (wrong bits set) |
| * @throws IOException if an i/o error occurs |
| */ |
| static void writeCRC(IndexOutput output) throws IOException { |
| long value = output.getChecksum(); |
| if ((value & 0xFFFFFFFF00000000L) != 0) { |
| throw new IllegalStateException("Illegal CRC-32 checksum: " + value + " (resource=" + output + ")"); |
| } |
| output.writeLong(value); |
| } |
| } |
