@UnstableApi
interface ExtractorInput : DataReader

Known direct subclasses
DefaultExtractorInput

An ExtractorInput that wraps a DataReader.

FakeExtractorInput

A fake ExtractorInput capable of simulating various scenarios.

ForwardingExtractorInput

An overridable ExtractorInput implementation forwarding all methods to another input.


Provides data to be consumed by an Extractor.

This interface provides two modes of accessing the underlying input. See the subheadings below for more info about each mode.

  • The read()/peek() and skip() methods provide InputStream-like byte-level access operations.
  • The read/skip/peekFully() and advancePeekPosition() methods assume the user wants to read an entire block/frame/header of known length.

InputStream-like methods

The read()/peek() and skip() methods provide InputStream-like byte-level access operations. The length parameter is a maximum, and each method returns the number of bytes actually processed. This may be less than length because the end of the input was reached, or the method was interrupted, or the operation was aborted early for another reason.

Block-based methods

The read/skip/peekFully() and advancePeekPosition() methods assume the user wants to read an entire block/frame/header of known length.

These methods all have a variant that takes a boolean allowEndOfInput parameter. This parameter is intended to be set to true when the caller believes the input might be fully exhausted before the call is made (i.e. they've previously read/skipped/peeked the final block/frame/header). It's not intended to allow a partial read (i.e. greater than 0 bytes, but less than length) to succeed - this will always throw an EOFException from these methods (a partial read is assumed to indicate a malformed block/frame/header - and therefore a malformed file).

The expected behaviour of the block-based methods is therefore:

  • Already at end-of-input and allowEndOfInput=false: Throw EOFException.
  • Already at end-of-input and allowEndOfInput=true: Return false.
  • Encounter end-of-input during read/skip/peek/advance: Throw EOFException (regardless of allowEndOfInput).

Summary

Public functions

Unit

Advances the peek position by length bytes.

Boolean
advancePeekPosition(length: Int, allowEndOfInput: Boolean)

Advances the peek position by length bytes.

Long

Returns the length of the source stream, or LENGTH_UNSET if it is unknown.

Long

Returns the current peek position (byte offset) in the stream.

Long

Returns the current read position (byte offset) in the stream.

Int
peek(target: ByteArray!, offset: Int, length: Int)

Peeks up to length bytes from the peek position.

Unit
peekFully(target: ByteArray!, offset: Int, length: Int)

Equivalent to peekFully(target, offset, length, false).

Boolean
peekFully(
    target: ByteArray!,
    offset: Int,
    length: Int,
    allowEndOfInput: Boolean
)

Like peek, but peeks the requested length in full.

Int
read(buffer: ByteArray!, offset: Int, length: Int)

Reads up to length bytes from the input and resets the peek position.

Unit
readFully(target: ByteArray!, offset: Int, length: Int)

Equivalent to readFully(target, offset, length, false).

Boolean
readFully(
    target: ByteArray!,
    offset: Int,
    length: Int,
    allowEndOfInput: Boolean
)

Like read, but reads the requested length in full.

Unit

Resets the peek position to equal the current read position.

Unit
<E : Throwable?> setRetryPosition(position: Long, e: E!)

Called when reading fails and the required retry position is different from the last position.

Int
skip(length: Int)

Like read, except the data is skipped instead of read.

Unit
skipFully(length: Int)

Like readFully, except the data is skipped instead of read.

Boolean
skipFully(length: Int, allowEndOfInput: Boolean)

Like readFully, except the data is skipped instead of read.

Public functions

advancePeekPosition

fun advancePeekPosition(length: Int): Unit

Advances the peek position by length bytes. Like peekFully except the data is skipped instead of read.

Parameters
length: Int

The number of bytes to peek from the input.

Throws
java.io.EOFException

If the end of input was encountered.

java.io.IOException

If an error occurs peeking from the input.

advancePeekPosition

fun advancePeekPosition(length: Int, allowEndOfInput: Boolean): Boolean

Advances the peek position by length bytes. Like peekFully except the data is skipped instead of read.

Parameters
length: Int

The number of bytes by which to advance the peek position.

allowEndOfInput: Boolean

True if encountering the end of the input before advancing is allowed, and should result in false being returned. False if it should be considered an error, causing an EOFException to be thrown. See note in class Javadoc.

Returns
Boolean

True if advancing the peek position was successful. False if allowEndOfInput=true and the end of the input was encountered before advancing over any data.

Throws
java.io.EOFException

If the end of input was encountered having partially advanced (i.e. having advanced by at least one byte, but fewer than length), or if the end of input was encountered before advancing and allowEndOfInput is false.

java.io.IOException

If an error occurs advancing the peek position.

getLength

fun getLength(): Long

Returns the length of the source stream, or LENGTH_UNSET if it is unknown.

Returns
Long

The length of the source stream, or LENGTH_UNSET.

getPeekPosition

fun getPeekPosition(): Long

Returns the current peek position (byte offset) in the stream.

Returns
Long

The peek position (byte offset) in the stream.

getPosition

fun getPosition(): Long

Returns the current read position (byte offset) in the stream.

Returns
Long

The read position (byte offset) in the stream.

peek

fun peek(target: ByteArray!, offset: Int, length: Int): Int

Peeks up to length bytes from the peek position. The current read position is left unchanged.

This method blocks until at least one byte of data can be peeked, the end of the input is detected, or an exception is thrown.

Calling resetPeekPosition resets the peek position to equal the current read position, so the caller can peek the same data again. Reading or skipping also resets the peek position.

Parameters
target: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The maximum number of bytes to peek from the input.

Returns
Int

The number of bytes peeked, or RESULT_END_OF_INPUT if the input has ended.

Throws
java.io.IOException

If an error occurs peeking from the input.

peekFully

fun peekFully(target: ByteArray!, offset: Int, length: Int): Unit

Equivalent to peekFully(target, offset, length, false).

Parameters
target: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The number of bytes to peek from the input.

Throws
java.io.EOFException

If the end of input was encountered.

java.io.IOException

If an error occurs peeking from the input.

peekFully

fun peekFully(
    target: ByteArray!,
    offset: Int,
    length: Int,
    allowEndOfInput: Boolean
): Boolean

Like peek, but peeks the requested length in full.

Parameters
target: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The number of bytes to peek from the input.

allowEndOfInput: Boolean

True if encountering the end of the input having peeked no data is allowed, and should result in false being returned. False if it should be considered an error, causing an EOFException to be thrown. See note in class Javadoc.

Returns
Boolean

True if the peek was successful. False if allowEndOfInput=true and the end of the input was encountered having peeked no data.

Throws
java.io.EOFException

If the end of input was encountered having partially satisfied the peek (i.e. having peeked at least one byte, but fewer than length), or if no bytes were peeked and allowEndOfInput is false.

java.io.IOException

If an error occurs peeking from the input.

read

fun read(buffer: ByteArray!, offset: Int, length: Int): Int

Reads up to length bytes from the input and resets the peek position.

This method blocks until at least one byte of data can be read, the end of the input is detected, or an exception is thrown.

Parameters
buffer: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The maximum number of bytes to read from the input.

Returns
Int

The number of bytes read, or RESULT_END_OF_INPUT if the input has ended.

Throws
java.io.IOException

If an error occurs reading from the input.

readFully

fun readFully(target: ByteArray!, offset: Int, length: Int): Unit

Equivalent to readFully(target, offset, length, false).

Parameters
target: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The number of bytes to read from the input.

Throws
java.io.EOFException

If the end of input was encountered.

java.io.IOException

If an error occurs reading from the input.

readFully

fun readFully(
    target: ByteArray!,
    offset: Int,
    length: Int,
    allowEndOfInput: Boolean
): Boolean

Like read, but reads the requested length in full.

Parameters
target: ByteArray!

A target array into which data should be written.

offset: Int

The offset into the target array at which to write.

length: Int

The number of bytes to read from the input.

allowEndOfInput: Boolean

True if encountering the end of the input having read no data is allowed, and should result in false being returned. False if it should be considered an error, causing an EOFException to be thrown. See note in class Javadoc.

Returns
Boolean

True if the read was successful. False if allowEndOfInput=true and the end of the input was encountered having read no data.

Throws
java.io.EOFException

If the end of input was encountered having partially satisfied the read (i.e. having read at least one byte, but fewer than length), or if no bytes were read and allowEndOfInput is false.

java.io.IOException

If an error occurs reading from the input.

resetPeekPosition

fun resetPeekPosition(): Unit

Resets the peek position to equal the current read position.

setRetryPosition

fun <E : Throwable?> setRetryPosition(position: Long, e: E!): Unit

Called when reading fails and the required retry position is different from the last position. After setting the retry position it throws the given Throwable.

Parameters
<E : Throwable?>

Type of Throwable to be thrown.

position: Long

The required retry position.

e: E!

Throwable to be thrown.

Throws
E

The given Throwable object.

skip

fun skip(length: Int): Int

Like read, except the data is skipped instead of read.

Parameters
length: Int

The maximum number of bytes to skip from the input.

Returns
Int

The number of bytes skipped, or RESULT_END_OF_INPUT if the input has ended.

Throws
java.io.IOException

If an error occurs reading from the input.

skipFully

fun skipFully(length: Int): Unit

Like readFully, except the data is skipped instead of read.

Encountering the end of input is always considered an error, and will result in an being thrown.

Parameters
length: Int

The number of bytes to skip from the input.

Throws
java.io.EOFException

If the end of input was encountered.

java.io.IOException

If an error occurs reading from the input.

skipFully

fun skipFully(length: Int, allowEndOfInput: Boolean): Boolean

Like readFully, except the data is skipped instead of read.

Parameters
length: Int

The number of bytes to skip from the input.

allowEndOfInput: Boolean

True if encountering the end of the input having skipped no data is allowed, and should result in false being returned. False if it should be considered an error, causing an EOFException to be thrown. See note in class Javadoc.

Returns
Boolean

True if the skip was successful. False if allowEndOfInput=true and the end of the input was encountered having skipped no data.

Throws
java.io.EOFException

If the end of input was encountered having partially satisfied the skip (i.e. having skipped at least one byte, but fewer than length), or if no bytes were skipped and allowEndOfInput is false.

java.io.IOException

If an error occurs reading from the input.