ByteReadChannel

expect interface ByteReadChannel

Channel for asynchronous reading of sequences of bytes. This is a single-reader channel.

Operations on this channel cannot be invoked concurrently.

Properties

availableForRead

abstract val availableForRead: Int

Returns number of bytes that can be read without suspension. Read operations do no suspend and return immediately when this number is at least the number of bytes requested for read.

isClosedForRead

abstract val isClosedForRead: Boolean

Returns true if the channel is closed and no remaining bytes are available for read. It implies that availableForRead is zero.

isClosedForWrite

abstract val isClosedForWrite: Boolean

readByteOrder

abstract var readByteOrder: ByteOrder

Byte order that is used for multi-byte read operations (such as readShort, readInt, readLong, readFloat, and readDouble).

totalBytesRead

abstract val totalBytesRead: Long

Number of bytes read from the channel. It is not guaranteed to be atomic so could be updated in the middle of long running read operation.

Functions

cancel

abstract fun cancel(cause: Throwable?): Boolean

Close channel with optional cause cancellation. Unlike ByteWriteChannel.close that could close channel normally, cancel does always close with error so any operations on this channel will always fail and all suspensions will be resumed with exception.

consumeEachBufferRange

open suspend fun consumeEachBufferRange(
    visitor: ConsumeEachBufferVisitor
): Unit

For every available bytes range invokes visitor function until it return false or end of stream encountered

discard

abstract suspend fun discard(max: Long): Long

Discard up to max bytes

lookAhead

abstract fun <R> lookAhead(
    visitor: LookAheadSession.() -> R
): R

lookAheadSuspend

abstract suspend fun <R> lookAheadSuspend(
    visitor: suspend LookAheadSuspendSession.() -> R
): R

peekTo

abstract suspend fun peekTo(
    destination: Memory,
    destinationOffset: Long,
    offset: Long = 0,
    min: Long = 1,
    max: Long = Long.MAX_VALUE
): Long

Try to copy at least min but up to max bytes to the specified destination buffer from this input skipping offset bytes. If there are not enough bytes available to provide min bytes after skipping offset bytes then it will trigger the underlying source reading first and after that will simply copy available bytes even if EOF encountered so min is not a requirement but a desired number of bytes. It is safe to specify max greater than the destination free space. min shouldn’t be bigger than the destination free space. This function could trigger the underlying source suspending reading. It is allowed to specify too big offset so in this case this function will always return 0 after prefetching all underlying bytes but note that it may lead to significant memory consumption. This function usually copy more bytes than min (unless max = min) but it is not guaranteed. When 0 is returned with offset = 0 then it makes sense to check isClosedForRead.

read

abstract suspend fun read(
    min: Int = 1,
    consumer: (ByteBuffer) -> Unit
): Unit

Invokes consumer when it will be possible to read at least min bytes providing byte buffer to it so lambda can read from the buffer up to ByteBuffer.remaining bytes. If there are no min bytes available then the invocation could suspend until the requirement will be met.

readAvailable

abstract suspend fun readAvailable(
    dst: ByteArray,
    offset: Int,
    length: Int
): Int

Reads all available bytes to dst buffer and returns immediately or suspends if no bytes available

abstract suspend fun readAvailable(dst: IoBuffer): Int
abstract suspend fun readAvailable(dst: ByteBuffer): Int

readBoolean

abstract suspend fun readBoolean(): Boolean

Reads a boolean value (suspending if no bytes available yet) or fails if channel has been closed and not enough bytes.

readByte

abstract suspend fun readByte(): Byte

Reads a byte (suspending if no bytes available yet) or fails if channel has been closed and not enough bytes.

readDouble

abstract suspend fun readDouble(): Double

Reads double number (suspending if not enough bytes available) or fails if channel has been closed and not enough bytes.

readFloat

abstract suspend fun readFloat(): Float

Reads float number (suspending if not enough bytes available) or fails if channel has been closed and not enough bytes.

readFully

abstract suspend fun readFully(
    dst: ByteArray,
    offset: Int,
    length: Int
): Unit

Reads all length bytes to dst buffer or fails if channel has been closed. Suspends if not enough bytes available.

abstract suspend fun readFully(dst: IoBuffer, n: Int): Unit
abstract suspend fun readFully(dst: ByteBuffer): Int

readInt

abstract suspend fun readInt(): Int

Reads an int number (suspending if not enough bytes available) or fails if channel has been closed and not enough bytes.

readLong

abstract suspend fun readLong(): Long

Reads a long number (suspending if not enough bytes available) or fails if channel has been closed and not enough bytes.

readPacket

abstract suspend fun readPacket(
    size: Int,
    headerSizeHint: Int
): ByteReadPacket

Reads the specified amount of bytes and makes a byte packet from them. Fails if channel has been closed and not enough bytes available. Accepts headerSizeHint to be provided, see BytePacketBuilder.

readRemaining

abstract suspend fun readRemaining(
    limit: Long,
    headerSizeHint: Int
): ByteReadPacket

Reads up to limit bytes and makes a byte packet or until end of stream encountered. Accepts headerSizeHint to be provided, see BytePacketBuilder.

readSession

abstract fun readSession(
    consumer: ReadSession.() -> Unit
): Unit

Starts non-suspendable read session. After channel preparation consumer lambda will be invoked immediately event if there are no bytes available for read yet.

readShort

abstract suspend fun readShort(): Short

Reads a short number (suspending if not enough bytes available) or fails if channel has been closed and not enough bytes.

readSuspendableSession

abstract suspend fun readSuspendableSession(
    consumer: suspend SuspendableReadSession.() -> Unit
): Unit

Starts a suspendable read session. After channel preparation consumer lambda will be invoked immediately even if there are no bytes available for read yet. consumer lambda could suspend as much as needed.

readUTF8Line

abstract suspend fun readUTF8Line(limit: Int): String?

Reads a line of UTF-8 characters up to limit characters. Supports both CR-LF and LF line endings. Throws an exception if the specified limit has been exceeded.

readUTF8LineTo

abstract suspend fun <A> readUTF8LineTo(
    out: A,
    limit: Int
): Boolean

Reads a line of UTF-8 characters to the specified out buffer up to limit characters. Supports both CR-LF and LF line endings. No line ending characters will be appended to out buffer. Throws an exception if the specified limit has been exceeded.

Companion Object Properties

Empty

val Empty: ByteReadChannel

Extension Functions

cancel

fun ByteReadChannel.cancel(): Boolean

consumeEachBufferRange

suspend fun ByteReadChannel.consumeEachBufferRange(
    visitor: ConsumeEachBufferVisitor
): Unit

For every available bytes range invokes visitor function until it return false or end of stream encountered

copyAndClose

suspend fun ByteReadChannel.copyAndClose(
    dst: ByteWriteChannel,
    limit: Long = Long.MAX_VALUE
): Long

Reads all the bytes from receiver channel and writes them to dst channel and then closes it. Closes dst channel if fails to read or write with cause exception.

copyTo

suspend expect fun ByteReadChannel.copyTo(
    dst: ByteWriteChannel,
    limit: Long = Long.MAX_VALUE
): Long

Reads up to limit bytes from receiver channel and writes them to dst channel. Closes dst channel if fails to read or write with cause exception.

copyTo

suspend fun ByteReadChannel.copyTo(
    out: OutputStream,
    limit: Long = Long.MAX_VALUE
): Long

Copies up to limit bytes from this byte channel to out stream suspending on read channel and blocking on output

copyTo

suspend fun ByteReadChannel.copyTo(
    channel: WritableByteChannel,
    limit: Long = Long.MAX_VALUE
): Long

Copy up to limit bytes to blocking NIO channel. Copying to non-blocking channel requires selection and not supported. It does suspend if no data available in byte channel but may block if destination NIO channel blocks.

suspend fun ByteReadChannel.copyTo(
    pipe: Pipe,
    limit: Long = Long.MAX_VALUE
): Long

Copy up to limit bytes to blocking pipe. A shortcut to copyTo function with NIO channel destination

copyToBoth

fun ByteReadChannel.copyToBoth(
    first: ByteWriteChannel,
    second: ByteWriteChannel
): Unit

Copy source channel to both output channels chunk by chunk.

deflated

fun ByteReadChannel.deflated(
    gzip: Boolean = true,
    pool: ObjectPool<ByteBuffer> = KtorDefaultPool,
    coroutineContext: <ERROR CLASS> = Dispatchers.Unconfined
): ByteReadChannel

Launch a coroutine on coroutineContext that does deflate compression optionally doing CRC and writing GZIP header and trailer if gzip = true

discard

suspend fun ByteReadChannel.discard(): Long

Discards all bytes in the channel and suspends until end of stream.

discardExact

suspend fun ByteReadChannel.discardExact(n: Long): Unit

Discards exactly n bytes or fails if not enough bytes in the channel

joinTo

suspend expect fun ByteReadChannel.joinTo(
    dst: ByteWriteChannel,
    closeOnEnd: Boolean
): Unit

pass

suspend fun ByteReadChannel.pass(
    buffer: ByteBuffer,
    block: (ByteBuffer) -> Unit
): Unit

Read data chunks from ByteReadChannel using buffer

read

suspend fun ByteReadChannel.read(
    desiredSize: Int = 1,
    block: (source: Memory, start: Long, endExclusive: Long) -> Int
): Int

Await until at least desiredSize is available for read or EOF and invoke block function. The block function should never capture a provided Memory instance outside otherwise an undefined behaviour may occur including accidental crash or data corruption. Block function should return number of bytes consumed or 0.

readAvailable

suspend fun ByteReadChannel.readAvailable(
    dst: ByteArray
): Int

readDouble

suspend fun ByteReadChannel.readDouble(
    byteOrder: ByteOrder
): Double

readDoubleLittleEndian

suspend fun ByteReadChannel.readDoubleLittleEndian(): Double

readFloat

suspend fun ByteReadChannel.readFloat(
    byteOrder: ByteOrder
): Float

readFloatLittleEndian

suspend fun ByteReadChannel.readFloatLittleEndian(): Float

readFully

suspend fun ByteReadChannel.readFully(dst: IoBuffer): Unit
suspend fun ByteReadChannel.readFully(dst: ByteArray): Unit

readInt

suspend fun ByteReadChannel.readInt(
    byteOrder: ByteOrder
): Int

readIntLittleEndian

suspend fun ByteReadChannel.readIntLittleEndian(): Int

readLong

suspend fun ByteReadChannel.readLong(
    byteOrder: ByteOrder
): Long

readLongLittleEndian

suspend fun ByteReadChannel.readLongLittleEndian(): Long

readPacket

suspend fun ByteReadChannel.readPacket(
    size: Int
): ByteReadPacket

Reads the specified amount of bytes and makes a byte packet from them. Fails if channel has been closed and not enough bytes available.

readRemaining

suspend fun ByteReadChannel.readRemaining(
    limit: Long
): ByteReadPacket

Reads up to limit bytes and makes a byte packet or until end of stream encountered.

suspend fun ByteReadChannel.readRemaining(): ByteReadPacket

Reads all remaining bytes and makes a byte packet

readShort

suspend fun ByteReadChannel.readShort(
    byteOrder: ByteOrder
): Short

readShortLittleEndian

suspend fun ByteReadChannel.readShortLittleEndian(): Short

readUTF8Line

suspend fun ByteReadChannel.readUTF8Line(): String?

readUTF8LineTo

suspend fun ByteReadChannel.readUTF8LineTo(
    out: Appendable
): Boolean

readUntilDelimiter

suspend fun ByteReadChannel.readUntilDelimiter(
    delimiter: ByteBuffer,
    dst: ByteBuffer
): Int

Reads from the channel to the specified dst byte buffer until one of the following:

skipDelimiter

suspend fun ByteReadChannel.skipDelimiter(
    delimiter: ByteBuffer
): Unit

split

fun ByteReadChannel.split(
    coroutineScope: CoroutineScope
): Pair<ByteReadChannel, ByteReadChannel>

Split source ByteReadChannel into 2 new one. Cancel of one channel in split(input or both outputs) cancels other channels.

toByteArray

suspend fun ByteReadChannel.toByteArray(): ByteArray

Read channel to byte array.

toByteArray

suspend fun ByteReadChannel.toByteArray(
    limit: Int = Int.MAX_VALUE
): ByteArray

Convert ByteReadChannel to ByteArray

toInputStream

fun ByteReadChannel.toInputStream(
    parent: Job? = null
): InputStream

Create blocking java.io.InputStream for this channel that does block every time the channel suspends at read Similar to do reading in runBlocking however you can pass it to regular blocking API

Inheritors

ByteChannel

interface ByteChannel : ByteReadChannel, ByteWriteChannel

Channel for asynchronous reading and writing of sequences of bytes. This is a buffered single-reader single-writer channel.

ByteChannelSequentialBase

abstract class ByteChannelSequentialBase : 
    ByteChannel,
    ByteReadChannel,
    ByteWriteChannel,
    SuspendableReadSession,
    HasReadSession,
    HasWriteSession

Sequential (non-concurrent) byte channel implementation