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compression.scala
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compression.scala
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/*
* Copyright (c) 2013 Functional Streams for Scala
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package fs2
import java.io.EOFException
import java.nio.charset.StandardCharsets
import java.time.Instant
import java.util.zip._
import cats.effect.Sync
/** Provides utilities for compressing/decompressing byte streams. */
object compression {
object ZLibParams {
sealed abstract class Header(private[compression] val juzDeflaterNoWrap: Boolean)
case object Header {
private[fs2] def apply(juzDeflaterNoWrap: Boolean): ZLibParams.Header =
if (juzDeflaterNoWrap) ZLibParams.Header.GZIP else ZLibParams.Header.ZLIB
case object ZLIB extends Header(juzDeflaterNoWrap = false)
case object GZIP extends Header(juzDeflaterNoWrap = true)
}
}
/**
* Deflate algorithm parameters.
*/
sealed trait DeflateParams {
/**
* Size of the internal buffer. Default size is 32 KB.
*/
val bufferSize: Int
/**
* Compression header. Defaults to [[ZLibParams.Header.ZLIB]].
*/
val header: ZLibParams.Header
/**
* Compression level. Default level is [[java.util.zip.Deflater.DEFAULT_COMPRESSION]].
*/
val level: DeflateParams.Level
/**
* Compression strategy. Default strategy is [[java.util.zip.Deflater.DEFAULT_STRATEGY]].
*/
val strategy: DeflateParams.Strategy
/**
* Compression flush mode. Default flush mode is [[java.util.zip.Deflater.NO_FLUSH]].
*/
val flushMode: DeflateParams.FlushMode
private[compression] val bufferSizeOrMinimum: Int = bufferSize.min(128)
}
object DeflateParams {
def apply(
bufferSize: Int = 1024 * 32,
header: ZLibParams.Header = ZLibParams.Header.ZLIB,
level: DeflateParams.Level = DeflateParams.Level.DEFAULT,
strategy: DeflateParams.Strategy = DeflateParams.Strategy.DEFAULT,
flushMode: DeflateParams.FlushMode = DeflateParams.FlushMode.DEFAULT
): DeflateParams =
DeflateParamsImpl(bufferSize, header, level, strategy, flushMode)
private case class DeflateParamsImpl(
bufferSize: Int,
header: ZLibParams.Header,
level: DeflateParams.Level,
strategy: DeflateParams.Strategy,
flushMode: DeflateParams.FlushMode
) extends DeflateParams
sealed abstract class Level(private[compression] val juzDeflaterLevel: Int)
case object Level {
private[fs2] def apply(level: Int): Level =
level match {
case DEFAULT.juzDeflaterLevel => Level.DEFAULT
case ZERO.juzDeflaterLevel => Level.ZERO
case ONE.juzDeflaterLevel => Level.ONE
case TWO.juzDeflaterLevel => Level.TWO
case THREE.juzDeflaterLevel => Level.THREE
case FOUR.juzDeflaterLevel => Level.FOUR
case FIVE.juzDeflaterLevel => Level.FIVE
case SIX.juzDeflaterLevel => Level.SIX
case SEVEN.juzDeflaterLevel => Level.SEVEN
case EIGHT.juzDeflaterLevel => Level.EIGHT
case NINE.juzDeflaterLevel => Level.NINE
}
case object DEFAULT extends Level(juzDeflaterLevel = Deflater.DEFAULT_COMPRESSION)
case object BEST_SPEED extends Level(juzDeflaterLevel = Deflater.BEST_SPEED)
case object BEST_COMPRESSION extends Level(juzDeflaterLevel = Deflater.BEST_COMPRESSION)
case object NO_COMPRESSION extends Level(juzDeflaterLevel = Deflater.NO_COMPRESSION)
case object ZERO extends Level(juzDeflaterLevel = 0)
case object ONE extends Level(juzDeflaterLevel = 1)
case object TWO extends Level(juzDeflaterLevel = 2)
case object THREE extends Level(juzDeflaterLevel = 3)
case object FOUR extends Level(juzDeflaterLevel = 4)
case object FIVE extends Level(juzDeflaterLevel = 5)
case object SIX extends Level(juzDeflaterLevel = 6)
case object SEVEN extends Level(juzDeflaterLevel = 7)
case object EIGHT extends Level(juzDeflaterLevel = 8)
case object NINE extends Level(juzDeflaterLevel = 9)
}
sealed abstract class Strategy(private[compression] val juzDeflaterStrategy: Int)
case object Strategy {
private[fs2] def apply(strategy: Int): Strategy =
strategy match {
case DEFAULT.juzDeflaterStrategy => Strategy.DEFAULT
case FILTERED.juzDeflaterStrategy => Strategy.FILTERED
case HUFFMAN_ONLY.juzDeflaterStrategy => Strategy.HUFFMAN_ONLY
}
case object DEFAULT extends Strategy(juzDeflaterStrategy = Deflater.DEFAULT_STRATEGY)
case object BEST_SPEED extends Strategy(juzDeflaterStrategy = Deflater.HUFFMAN_ONLY)
case object BEST_COMPRESSION extends Strategy(juzDeflaterStrategy = Deflater.DEFAULT_STRATEGY)
case object FILTERED extends Strategy(juzDeflaterStrategy = Deflater.FILTERED)
case object HUFFMAN_ONLY extends Strategy(juzDeflaterStrategy = Deflater.HUFFMAN_ONLY)
}
sealed abstract class FlushMode(private[compression] val juzDeflaterFlushMode: Int)
case object FlushMode {
private[fs2] def apply(flushMode: Int): FlushMode =
flushMode match {
case DEFAULT.juzDeflaterFlushMode => FlushMode.NO_FLUSH
case SYNC_FLUSH.juzDeflaterFlushMode => FlushMode.SYNC_FLUSH
case FULL_FLUSH.juzDeflaterFlushMode => FlushMode.FULL_FLUSH
}
case object DEFAULT extends FlushMode(juzDeflaterFlushMode = Deflater.NO_FLUSH)
case object BEST_SPEED extends FlushMode(juzDeflaterFlushMode = Deflater.FULL_FLUSH)
case object BEST_COMPRESSION extends FlushMode(juzDeflaterFlushMode = Deflater.NO_FLUSH)
case object NO_FLUSH extends FlushMode(juzDeflaterFlushMode = Deflater.NO_FLUSH)
case object SYNC_FLUSH extends FlushMode(juzDeflaterFlushMode = Deflater.SYNC_FLUSH)
case object FULL_FLUSH extends FlushMode(juzDeflaterFlushMode = Deflater.FULL_FLUSH)
}
/**
* Reasonable defaults for most applications.
*/
val DEFAULT: DeflateParams = DeflateParams()
/**
* Best speed for real-time, intermittent, fragmented, interactive or discontinuous streams.
*/
val BEST_SPEED: DeflateParams = DeflateParams(
level = Level.BEST_SPEED,
strategy = Strategy.BEST_SPEED,
flushMode = FlushMode.BEST_SPEED
)
/**
* Best compression for finite, complete, readily-available, continuous or file streams.
*/
val BEST_COMPRESSION: DeflateParams = DeflateParams(
bufferSize = 1024 * 128,
level = Level.BEST_COMPRESSION,
strategy = Strategy.BEST_COMPRESSION,
flushMode = FlushMode.BEST_COMPRESSION
)
}
/**
* Returns a `Pipe` that deflates (compresses) its input elements using
* the the Deflate algorithm.
*
* @param deflateParams See [[compression.DeflateParams]]
*/
def deflate[F[_]](
deflateParams: DeflateParams
)(implicit SyncF: Sync[F]): Pipe[F, Byte, Byte] =
stream =>
Stream
.bracket(
SyncF.delay {
val deflater =
new Deflater(
deflateParams.level.juzDeflaterLevel,
deflateParams.header.juzDeflaterNoWrap
)
deflater.setStrategy(deflateParams.strategy.juzDeflaterStrategy)
deflater
}
)(deflater => SyncF.delay(deflater.end()))
.flatMap(deflater => _deflate(deflateParams, deflater, crc32 = None)(stream))
private def _deflate[F[_]](
deflateParams: DeflateParams,
deflater: Deflater,
crc32: Option[CRC32]
): Pipe[F, Byte, Byte] =
_deflate_stream(deflateParams, deflater, crc32)(_).stream
private def _deflate_chunk[F[_]](
deflateParams: DeflateParams,
deflater: Deflater,
crc32: Option[CRC32],
chunk: Chunk[Byte],
isFinalChunk: Boolean
): Pull[F, Byte, Unit] = {
val bytesChunk = chunk.toBytes
deflater.setInput(
bytesChunk.values,
bytesChunk.offset,
bytesChunk.length
)
if (isFinalChunk)
deflater.finish()
crc32.foreach(_.update(bytesChunk.values, bytesChunk.offset, bytesChunk.length))
def isDone: Boolean =
(isFinalChunk && deflater.finished) || (!isFinalChunk && deflater.needsInput)
def deflateInto(deflatedBuffer: Array[Byte]): Int =
if (isDone) 0
else
deflater.deflate(
deflatedBuffer,
0,
deflateParams.bufferSizeOrMinimum,
deflateParams.flushMode.juzDeflaterFlushMode
)
def pull(): Pull[F, Byte, Unit] = {
val deflatedBuffer = new Array[Byte](deflateParams.bufferSizeOrMinimum)
val deflatedBytes = deflateInto(deflatedBuffer)
if (isDone)
Pull.output(asChunkBytes(deflatedBuffer, deflatedBytes))
else
Pull.output(asChunkBytes(deflatedBuffer, deflatedBytes)) >> pull()
}
pull()
}
private def _deflate_stream[F[_]](
deflateParams: DeflateParams,
deflater: Deflater,
crc32: Option[CRC32]
): Stream[F, Byte] => Pull[F, Byte, Unit] =
_.pull.unconsNonEmpty.flatMap {
case Some((inflatedChunk, inflatedStream)) =>
_deflate_chunk(deflateParams, deflater, crc32, inflatedChunk, isFinalChunk = false) >>
_deflate_stream(deflateParams, deflater, crc32)(inflatedStream)
case None =>
_deflate_chunk(deflateParams, deflater, crc32, Chunk.empty[Byte], isFinalChunk = true)
}
/**
* Inflate algorithm parameters.
*/
sealed trait InflateParams {
/**
* Size of the internal buffer. Default size is 32 KB.
*/
val bufferSize: Int
/**
* Compression header. Defaults to [[ZLibParams.Header.ZLIB]]
*/
val header: ZLibParams.Header
private[compression] val bufferSizeOrMinimum: Int = bufferSize.min(128)
}
object InflateParams {
def apply(
bufferSize: Int = 1024 * 32,
header: ZLibParams.Header = ZLibParams.Header.ZLIB
): InflateParams =
InflateParamsImpl(bufferSize, header)
/**
* Reasonable defaults for most applications.
*/
val DEFAULT: InflateParams = InflateParams()
private case class InflateParamsImpl(
bufferSize: Int,
header: ZLibParams.Header
) extends InflateParams
}
/**
* Returns a `Pipe` that inflates (decompresses) its input elements using
* a `java.util.zip.Inflater` with the parameter `nowrap`.
* @param inflateParams See [[compression.InflateParams]]
*/
def inflate[F[_]](
inflateParams: InflateParams
)(implicit SyncF: Sync[F]): Pipe[F, Byte, Byte] =
stream =>
Stream
.bracket(SyncF.delay(new Inflater(inflateParams.header.juzDeflaterNoWrap)))(inflater =>
SyncF.delay(inflater.end())
)
.flatMap(inflater => _inflate(inflateParams, inflater, crc32 = None)(SyncF)(stream))
private def _inflate[F[_]](
inflateParams: InflateParams,
inflater: Inflater,
crc32: Option[CRC32]
)(implicit
SyncF: Sync[F]
): Pipe[F, Byte, Byte] =
_.pull.unconsNonEmpty.flatMap {
case Some((deflatedChunk, deflatedStream)) =>
_inflate_chunk(inflateParams, inflater, crc32, deflatedChunk) >> _inflate_stream(
inflateParams,
inflater,
crc32
)(SyncF)(deflatedStream)
case None =>
Pull.done
}.stream
private def _inflate_chunk[F[_]](
inflaterParams: InflateParams,
inflater: Inflater,
crc32: Option[CRC32],
chunk: Chunk[Byte]
): Pull[F, Byte, Unit] = {
val bytesChunk = chunk.toBytes
inflater.setInput(
bytesChunk.values,
bytesChunk.offset,
bytesChunk.length
)
def inflateInto(inflatedBuffer: Array[Byte]): Int =
if (inflater.finished()) -2
else if (inflater.needsInput()) -1
else {
val byteCount = inflater.inflate(inflatedBuffer)
crc32.foreach(_.update(inflatedBuffer, 0, byteCount))
byteCount
}
def pull(): Pull[F, Byte, Unit] = {
val inflatedBuffer = new Array[Byte](inflaterParams.bufferSizeOrMinimum)
inflateInto(inflatedBuffer) match {
case inflatedBytes if inflatedBytes <= -2 =>
inflater.getRemaining match {
case bytesRemaining if bytesRemaining > 0 =>
Pull.output(
Chunk.Bytes(
bytesChunk.values,
bytesChunk.offset + bytesChunk.length - bytesRemaining,
bytesRemaining
)
)
case _ =>
Pull.done
}
case inflatedBytes if inflatedBytes == -1 =>
Pull.done
case inflatedBytes if inflatedBytes < inflatedBuffer.length =>
if (inflater.finished())
inflater.getRemaining match {
case bytesRemaining if bytesRemaining > 0 =>
Pull.output(asChunkBytes(inflatedBuffer, inflatedBytes)) >>
Pull.output(
Chunk.Bytes(
bytesChunk.values,
bytesChunk.offset + bytesChunk.length - bytesRemaining,
bytesRemaining
)
)
case _ =>
Pull.output(asChunkBytes(inflatedBuffer, inflatedBytes))
}
else Pull.output(asChunkBytes(inflatedBuffer, inflatedBytes))
case inflatedBytes =>
Pull.output(asChunkBytes(inflatedBuffer, inflatedBytes)) >> pull()
}
}
pull()
}
private def _inflate_stream[F[_]](
inflateParams: InflateParams,
inflater: Inflater,
crc32: Option[CRC32]
)(implicit SyncF: Sync[F]): Stream[F, Byte] => Pull[F, Byte, Unit] =
_.pull.unconsNonEmpty.flatMap {
case Some((deflatedChunk, deflatedStream)) =>
_inflate_chunk(inflateParams, inflater, crc32, deflatedChunk) >> _inflate_stream(
inflateParams,
inflater,
crc32
)(SyncF)(deflatedStream)
case None =>
if (!inflater.finished)
Pull.raiseError[F](new DataFormatException("Insufficient data"))
else
Pull.done
}
/**
* Returns a pipe that incrementally compresses input into the GZIP format
* as defined by RFC 1952 at https://www.ietf.org/rfc/rfc1952.txt. Output is
* compatible with the GNU utils `gunzip` utility, as well as really anything
* else that understands GZIP. Note, however, that the GZIP format is not
* "stable" in the sense that all compressors will produce identical output
* given identical input. Part of the header seeding is arbitrary and chosen by
* the compression implementation. For this reason, the exact bytes produced
* by this pipe will differ in insignificant ways from the exact bytes produced
* by a tool like the GNU utils `gzip`.
*
* GZIP wraps a deflate stream with file attributes and stream integrity validation.
* Therefore, GZIP is a good choice for compressing finite, complete, readily-available,
* continuous or file streams. A simpler deflate stream may be better suited to
* real-time, intermittent, fragmented, interactive or discontinuous streams where
* network protocols typically provide stream integrity validation.
*
* @param bufferSize The buffer size which will be used to page data
* into chunks. This will be the chunk size of the
* output stream. You should set it to be equal to
* the size of the largest chunk in the input stream.
* Setting this to a size which is ''smaller'' than
* the chunks in the input stream will result in
* performance degradation of roughly 50-75%. Default
* size is 32 KB.
* @param deflateLevel level the compression level (0-9)
* @param deflateStrategy strategy compression strategy -- see `java.util.zip.Deflater` for details
* @param modificationTime optional file modification time
* @param fileName optional file name
* @param comment optional file comment
*/
def gzip[F[_]](
bufferSize: Int = 1024 * 32,
deflateLevel: Option[Int] = None,
deflateStrategy: Option[Int] = None,
modificationTime: Option[Instant] = None,
fileName: Option[String] = None,
comment: Option[String] = None
)(implicit SyncF: Sync[F]): Pipe[F, Byte, Byte] =
gzip[F](
fileName = fileName,
modificationTime = modificationTime,
comment = comment,
deflateParams = DeflateParams(
bufferSize = bufferSize,
header = ZLibParams.Header.GZIP,
level = deflateLevel
.map(DeflateParams.Level.apply)
.getOrElse(DeflateParams.Level.DEFAULT),
strategy = deflateStrategy
.map(DeflateParams.Strategy.apply)
.getOrElse(DeflateParams.Strategy.DEFAULT),
flushMode = DeflateParams.FlushMode.DEFAULT
)
)
/**
* Returns a pipe that incrementally compresses input into the GZIP format
* as defined by RFC 1952 at https://www.ietf.org/rfc/rfc1952.txt. Output is
* compatible with the GNU utils `gunzip` utility, as well as really anything
* else that understands GZIP. Note, however, that the GZIP format is not
* "stable" in the sense that all compressors will produce identical output
* given identical input. Part of the header seeding is arbitrary and chosen by
* the compression implementation. For this reason, the exact bytes produced
* by this pipe will differ in insignificant ways from the exact bytes produced
* by a tool like the GNU utils `gzip`.
*
* GZIP wraps a deflate stream with file attributes and stream integrity validation.
* Therefore, GZIP is a good choice for compressing finite, complete, readily-available,
* continuous or file streams. A simpler deflate stream may be better suited to
* real-time, intermittent, fragmented, interactive or discontinuous streams where
* network protocols typically provide stream integrity validation.
*
* @param fileName optional file name
* @param modificationTime optional file modification time
* @param comment optional file comment
* @param deflateParams see [[compression.DeflateParams]]
*/
def gzip[F[_]](
fileName: Option[String],
modificationTime: Option[Instant],
comment: Option[String],
deflateParams: DeflateParams
)(implicit SyncF: Sync[F]): Pipe[F, Byte, Byte] =
stream =>
deflateParams match {
case params: DeflateParams if params.header == ZLibParams.Header.GZIP =>
Stream
.bracket(
SyncF.delay {
val deflater = new Deflater(params.level.juzDeflaterLevel, true)
deflater.setStrategy(params.strategy.juzDeflaterStrategy)
(deflater, new CRC32())
}
) { case (deflater, _) => SyncF.delay(deflater.end()) }
.flatMap {
case (deflater, crc32) =>
_gzip_header(fileName, modificationTime, comment, params.level.juzDeflaterLevel) ++
_deflate(
params,
deflater,
Some(crc32)
)(stream) ++
_gzip_trailer(deflater, crc32)
}
case params: DeflateParams =>
Stream.raiseError(
new ZipException(
s"${ZLibParams.Header.GZIP} header type required, not ${params.header}."
)
)
}
private def _gzip_header[F[_]](
fileName: Option[String],
modificationTime: Option[Instant],
comment: Option[String],
deflateLevel: Int
): Stream[F, Byte] = {
// See RFC 1952: https://www.ietf.org/rfc/rfc1952.txt
val secondsSince197001010000: Long =
modificationTime.map(_.getEpochSecond).getOrElse(0)
val header = Array[Byte](
gzipMagicFirstByte, // ID1: Identification 1
gzipMagicSecondByte, // ID2: Identification 2
gzipCompressionMethod.DEFLATE, // CM: Compression Method
(gzipFlag.FHCRC + // FLG: Header CRC
fileName.map(_ => gzipFlag.FNAME).getOrElse(zeroByte) + // FLG: File name
comment.map(_ => gzipFlag.FCOMMENT).getOrElse(zeroByte)).toByte, // FLG: Comment
(secondsSince197001010000 & 0xff).toByte, // MTIME: Modification Time
((secondsSince197001010000 >> 8) & 0xff).toByte,
((secondsSince197001010000 >> 16) & 0xff).toByte,
((secondsSince197001010000 >> 24) & 0xff).toByte,
deflateLevel match { // XFL: Extra flags
case Deflater.BEST_COMPRESSION => gzipExtraFlag.DEFLATE_MAX_COMPRESSION_SLOWEST_ALGO
case Deflater.BEST_SPEED => gzipExtraFlag.DEFLATE_FASTEST_ALGO
case _ => zeroByte
},
gzipOperatingSystem.THIS
) // OS: Operating System
val crc32 = new CRC32()
crc32.update(header)
val fileNameEncoded = fileName.map { string =>
val bytes = string.replaceAll("\u0000", "_").getBytes(StandardCharsets.ISO_8859_1)
crc32.update(bytes)
crc32.update(zeroByte.toInt)
bytes
}
val commentEncoded = comment.map { string =>
val bytes = string.replaceAll("\u0000", " ").getBytes(StandardCharsets.ISO_8859_1)
crc32.update(bytes)
crc32.update(zeroByte.toInt)
bytes
}
val crc32Value = crc32.getValue
val crc16 = Array[Byte](
(crc32Value & 0xff).toByte,
((crc32Value >> 8) & 0xff).toByte
)
Stream.chunk(asChunkBytes(header)) ++
fileNameEncoded
.map(bytes => Stream.chunk(asChunkBytes(bytes)) ++ Stream.emit(zeroByte))
.getOrElse(Stream.empty) ++
commentEncoded
.map(bytes => Stream.chunk(asChunkBytes(bytes)) ++ Stream.emit(zeroByte))
.getOrElse(Stream.empty) ++
Stream.chunk(asChunkBytes(crc16))
}
private def _gzip_trailer[F[_]](deflater: Deflater, crc32: CRC32): Stream[F, Byte] = {
// See RFC 1952: https://www.ietf.org/rfc/rfc1952.txt
val crc32Value = crc32.getValue
val bytesIn = deflater.getTotalIn
val trailer = Array[Byte](
(crc32Value & 0xff).toByte, // CRC-32: Cyclic Redundancy Check
((crc32Value >> 8) & 0xff).toByte,
((crc32Value >> 16) & 0xff).toByte,
((crc32Value >> 24) & 0xff).toByte,
(bytesIn & 0xff).toByte, // ISIZE: Input size
((bytesIn >> 8) & 0xff).toByte,
((bytesIn >> 16) & 0xff).toByte,
((bytesIn >> 24) & 0xff).toByte
)
Stream.chunk(asChunkBytes(trailer))
}
/**
* Gunzip decompression results including file properties and
* decompressed content stream, used as follows:
* stream
* .through(gunzip[IO]())
* .flatMap { gunzipResult =>
* // Access properties here.
* gunzipResult.content
* }
*
* @param content Uncompressed content stream.
* @param modificationTime Modification time of compressed file.
* @param fileName File name.
* @param comment File comment.
*/
final case class GunzipResult[F[_]](
content: Stream[F, Byte],
modificationTime: Option[Instant] = None,
fileName: Option[String] = None,
comment: Option[String] = None
)
/**
* Returns a pipe that incrementally decompresses input according to the GZIP
* format as defined by RFC 1952 at https://www.ietf.org/rfc/rfc1952.txt. Any
* errors in decompression will be sequenced as exceptions into the output
* stream. Decompression is handled in a streaming and async fashion without
* any thread blockage.
*
* The chunk size here is actually really important. Matching the input stream
* largest chunk size, or roughly 8 KB (whichever is larger) is a good rule of
* thumb.
*
* @param bufferSize The bounding size of the input buffer. This should roughly
* match the size of the largest chunk in the input stream.
* This will also be the chunk size in the output stream.
* Default size is 32 KB.
* @return See [[compression.GunzipResult]]
*/
def gunzip[F[_]](
bufferSize: Int = 1024 * 32
)(implicit SyncF: Sync[F]): Stream[F, Byte] => Stream[F, GunzipResult[F]] =
gunzip(
InflateParams(
bufferSize = bufferSize,
header = ZLibParams.Header.GZIP
)
)
/**
* Returns a pipe that incrementally decompresses input according to the GZIP
* format as defined by RFC 1952 at https://www.ietf.org/rfc/rfc1952.txt. Any
* errors in decompression will be sequenced as exceptions into the output
* stream. Decompression is handled in a streaming and async fashion without
* any thread blockage.
*
* The chunk size here is actually really important. Matching the input stream
* largest chunk size, or roughly 8 KB (whichever is larger) is a good rule of
* thumb.
*
* @param inflateParams See [[compression.InflateParams]]
* @return See [[compression.GunzipResult]]
*/
def gunzip[F[_]](
inflateParams: InflateParams
)(implicit SyncF: Sync[F]): Stream[F, Byte] => Stream[F, GunzipResult[F]] =
stream =>
inflateParams match {
case params: InflateParams if params.header == ZLibParams.Header.GZIP =>
Stream
.bracket(SyncF.delay((new Inflater(true), new CRC32(), new CRC32()))) {
case (inflater, _, _) => SyncF.delay(inflater.end())
}
.flatMap {
case (inflater, headerCrc32, contentCrc32) =>
stream.pull
.unconsN(gzipHeaderBytes)
.flatMap {
case Some((mandatoryHeaderChunk, streamAfterMandatoryHeader)) =>
_gunzip_matchMandatoryHeader(
params,
mandatoryHeaderChunk,
streamAfterMandatoryHeader,
headerCrc32,
contentCrc32,
inflater
)
case None =>
Pull.output1(GunzipResult(Stream.raiseError(new EOFException())))
}
.stream
}
case params: InflateParams =>
Stream.raiseError(
new ZipException(
s"${ZLibParams.Header.GZIP} header type required, not ${params.header}."
)
)
}
private def _gunzip_matchMandatoryHeader[F[_]](
inflateParams: InflateParams,
mandatoryHeaderChunk: Chunk[Byte],
streamAfterMandatoryHeader: Stream[F, Byte],
headerCrc32: CRC32,
contentCrc32: CRC32,
inflater: Inflater
)(implicit SyncF: Sync[F]) =
(mandatoryHeaderChunk.size, mandatoryHeaderChunk.toBytes.values) match {
case (
`gzipHeaderBytes`,
Array(
`gzipMagicFirstByte`,
`gzipMagicSecondByte`,
gzipCompressionMethod.DEFLATE,
flags,
_,
_,
_,
_,
_
)
) if gzipFlag.reserved5(flags) =>
Pull.output1(
GunzipResult(
Stream.raiseError(
new ZipException("Unsupported gzip flag reserved bit 5 is non-zero")
)
)
)
case (
`gzipHeaderBytes`,
Array(
`gzipMagicFirstByte`,
`gzipMagicSecondByte`,
gzipCompressionMethod.DEFLATE,
flags,
_,
_,
_,
_,
_
)
) if gzipFlag.reserved6(flags) =>
Pull.output1(
GunzipResult(
Stream.raiseError(
new ZipException("Unsupported gzip flag reserved bit 6 is non-zero")
)
)
)
case (
`gzipHeaderBytes`,
Array(
`gzipMagicFirstByte`,
`gzipMagicSecondByte`,
gzipCompressionMethod.DEFLATE,
flags,
_,
_,
_,
_,
_
)
) if gzipFlag.reserved7(flags) =>
Pull.output1(
GunzipResult(
Stream.raiseError(
new ZipException("Unsupported gzip flag reserved bit 7 is non-zero")
)
)
)
case (
`gzipHeaderBytes`,
header @ Array(
`gzipMagicFirstByte`,
`gzipMagicSecondByte`,
gzipCompressionMethod.DEFLATE,
flags,
_,
_,
_,
_,
_,
_
)
) =>
headerCrc32.update(header)
val secondsSince197001010000 =
unsignedToLong(header(4), header(5), header(6), header(7))
_gunzip_readOptionalHeader(
inflateParams,
streamAfterMandatoryHeader,
flags,
headerCrc32,
contentCrc32,
secondsSince197001010000,
inflater
).pull.uncons1
.flatMap {
case Some((gunzipResult, _)) =>
Pull.output1(gunzipResult)
case None =>
Pull.output1(GunzipResult(Stream.raiseError(new EOFException())))
}
case (
`gzipHeaderBytes`,
Array(
`gzipMagicFirstByte`,
`gzipMagicSecondByte`,
compressionMethod,
_,
_,
_,
_,
_,
_,
_
)
) =>
Pull.output1(
GunzipResult(
Stream.raiseError(
new ZipException(
s"Unsupported gzip compression method: $compressionMethod"
)
)
)
)
case _ =>
Pull.output1(
GunzipResult(Stream.raiseError(new ZipException("Not in gzip format")))
)
}
private def _gunzip_readOptionalHeader[F[_]](
inflateParams: InflateParams,
streamAfterMandatoryHeader: Stream[F, Byte],
flags: Byte,
headerCrc32: CRC32,
contentCrc32: CRC32,
secondsSince197001010000: Long,
inflater: Inflater
)(implicit SyncF: Sync[F]): Stream[F, GunzipResult[F]] =
streamAfterMandatoryHeader
.through(_gunzip_skipOptionalExtraField(gzipFlag.fextra(flags), headerCrc32))
.through(
_gunzip_readOptionalStringField(
gzipFlag.fname(flags),
headerCrc32,
"file name",
fileNameBytesSoftLimit
)
)
.flatMap {
case (fileName, streamAfterFileName) =>
streamAfterFileName
.through(
_gunzip_readOptionalStringField(
gzipFlag.fcomment(flags),
headerCrc32,
"file comment",
fileCommentBytesSoftLimit
)
)
.flatMap {
case (comment, streamAfterComment) =>
Stream.emit(
GunzipResult(
modificationTime =
if (secondsSince197001010000 != 0)
Some(Instant.ofEpochSecond(secondsSince197001010000))
else None,
fileName = fileName,
comment = comment,
content = streamAfterComment
.through(
_gunzip_validateHeader(
(flags & gzipFlag.FHCRC) == gzipFlag.FHCRC,
headerCrc32
)
)
.through(
_inflate(
inflateParams = inflateParams,
inflater = inflater,
crc32 = Some(contentCrc32)
)
)
.through(_gunzip_validateTrailer(contentCrc32, inflater))
)
)
}
}
private def _gunzip_skipOptionalExtraField[F[_]](
isPresent: Boolean,
crc32: CRC32
)(implicit Sync: Sync[F]): Pipe[F, Byte, Byte] =
stream =>
if (isPresent)
stream.pull
.unconsN(gzipOptionalExtraFieldLengthBytes)
.flatMap {
case Some((optionalExtraFieldLengthChunk, streamAfterOptionalExtraFieldLength)) =>
(
optionalExtraFieldLengthChunk.size,
optionalExtraFieldLengthChunk.toBytes.values
) match {
case (
`gzipOptionalExtraFieldLengthBytes`,
lengthBytes @ Array(firstByte, secondByte)
) =>
crc32.update(lengthBytes)
val optionalExtraFieldLength = unsignedToInt(firstByte, secondByte)
streamAfterOptionalExtraFieldLength.pull
.unconsN(optionalExtraFieldLength)
.flatMap {
case Some((optionalExtraFieldChunk, streamAfterOptionalExtraField)) =>
val fieldBytes = optionalExtraFieldChunk.toBytes
crc32.update(fieldBytes.values, fieldBytes.offset, fieldBytes.length)
Pull.output1(streamAfterOptionalExtraField)
case None =>
Pull.raiseError(
new ZipException("Failed to read optional extra field header")
)
}
case _ =>
Pull.raiseError(
new ZipException("Failed to read optional extra field header length")
)
}
case None =>
Pull.raiseError(new EOFException())
}
.stream
.flatten
else stream
private def _gunzip_readOptionalStringField[F[_]](
isPresent: Boolean,
crc32: CRC32,
fieldName: String,
fieldBytesSoftLimit: Int
)(implicit
SyncF: Sync[F]
): Stream[F, Byte] => Stream[F, (Option[String], Stream[F, Byte])] =
stream =>
if (isPresent)
unconsUntil[F, Byte](_ == zeroByte, fieldBytesSoftLimit)(stream).flatMap {
case Some((chunk, rest)) =>
Pull.output1(
(
if (chunk.isEmpty)
Some("")
else {
val bytesChunk = chunk.toBytes
crc32.update(bytesChunk.values, bytesChunk.offset, bytesChunk.length)
Some(
new String(
bytesChunk.values,
bytesChunk.offset,
bytesChunk.length,
StandardCharsets.ISO_8859_1
)
)
},
rest
.dropWhile { byte =>
// Will also call crc32.update(byte) for the zeroByte dropped hereafter.
crc32.update(byte.toInt)
byte != zeroByte
}
.drop(1)
)
)
case None =>
Pull.output1(
(
Option.empty[String],
Stream.raiseError(new ZipException(s"Failed to read $fieldName field"))
)
)
}.stream
else Stream.emit((Option.empty[String], stream))