core/org.gnit.lucenekmp.codecs/CodecUtil

CodecUtil

object CodecUtil

Utility class for reading and writing versioned headers.

Writing codec headers is useful to ensure that a file is in the format you think it is.

Properties

const val CODEC_MAGIC: Int = 1071082519

Constant to identify the start of a codec header.

const val FOOTER_MAGIC: Int

Constant to identify the start of a codec footer.

Functions

fun checkFooter(in: ChecksumIndexInput): Long

Validates the codec footer previously written by .writeFooter.

fun checkFooter(in: ChecksumIndexInput, priorException: Throwable?)

Validates the codec footer previously written by .writeFooter, optionally passing an unexpected exception that has already occurred.

fun checkHeader(in: DataInput, codec: String?, minVersion: Int, maxVersion: Int): Int

Reads and validates a header previously written with .writeHeader.

checkHeaderNoMagic

fun checkHeaderNoMagic(in: DataInput, codec: String?, minVersion: Int, maxVersion: Int): Int

Like .checkHeader except this version assumes the first int has already been read and validated from the input.

checkIndexHeader

fun checkIndexHeader(in: DataInput, codec: String?, minVersion: Int, maxVersion: Int, expectedID: ByteArray?, expectedSuffix: String?): Int

Reads and validates a header previously written with .writeIndexHeader.

checkIndexHeaderID

fun checkIndexHeaderID(in: DataInput, expectedID: ByteArray?): ByteArray

Expert: just reads and verifies the object ID of an index header

checkIndexHeaderSuffix

fun checkIndexHeaderSuffix(in: DataInput, expectedSuffix: String?): String

Expert: just reads and verifies the suffix of an index header

checksumEntireFile

fun checksumEntireFile(input: IndexInput): Long

Clones the provided input, reads all bytes from the file, and calls .checkFooter

fun footerLength(): Int

Computes the length of a codec footer.

fun headerLength(codec: String): Int

Computes the length of a codec header.

indexHeaderLength

fun indexHeaderLength(codec: String, suffix: String): Int

Computes the length of an index header.

fun readBEInt(in: DataInput): Int

read int value from header / footer with big endian order

fun readBELong(in: DataInput): Long

read long value from header / footer with big endian order

fun readCRC(input: IndexInput): Long

Reads CRC32 value as a 64-bit long from the input.

fun readFooter(in: IndexInput): ByteArray

Retrieves the full footer from the provided IndexInput. This throws [ ] if this file does not have a valid footer.

readIndexHeader

fun readIndexHeader(in: IndexInput): ByteArray

Retrieves the full index header from the provided IndexInput. This throws [ ] if this file does not appear to be an index file.

retrieveChecksum

fun retrieveChecksum(in: IndexInput): Long

fun retrieveChecksum(in: IndexInput, expectedLength: Long): Long

Returns (but does not validate) the checksum previously written by .checkFooter.

verifyAndCopyIndexHeader

fun verifyAndCopyIndexHeader(in: IndexInput, out: DataOutput, expectedID: ByteArray)

Expert: verifies the incoming IndexInput has an index header and that its segment ID matches the expected one, and then copies that index header into the provided [ ]. This is useful when building compound files.

fun writeBEInt(out: DataOutput, i: Int)

write int value on header / footer with big endian order

fun writeBELong(out: DataOutput, l: Long)

write long value on header / footer with big endian order

fun writeCRC(output: IndexOutput)

Writes CRC32 value as a 64-bit long to the output.

fun writeFooter(out: IndexOutput)

Writes a codec footer, which records both a checksum algorithm ID and a checksum. This footer can be parsed and validated with .checkFooter.

fun writeHeader(out: DataOutput, codec: String, version: Int)

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 .checkHeader.

writeIndexHeader

fun writeIndexHeader(out: DataOutput, codec: String, version: Int, id: ByteArray, suffix: String)

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).