juce::MemoryOutputStream Class Reference

Writes data to an internal memory buffer, which grows as required. More...

#include <juce_MemoryOutputStream.h>

Inheritance diagram for juce::MemoryOutputStream:

Collaboration diagram for juce::MemoryOutputStream:

Public Member Functions
	MemoryOutputStream (MemoryBlock &memoryBlockToWriteTo, bool appendToExistingBlockContent)
	Creates a memory stream for writing into into a pre-existing MemoryBlock object. More...
	MemoryOutputStream (size_t initialSize=256)
	Creates an empty memory stream, ready to be written into. More...
	MemoryOutputStream (void *destBuffer, size_t destBufferSize)
	Creates a MemoryOutputStream that will write into a user-supplied, fixed-size block of memory. More...
	~MemoryOutputStream () override
	Destructor. More...
bool	appendUTF8Char (juce_wchar character)
	Appends the utf-8 bytes for a unicode character. More...
void	flush () override
	If the stream is writing to a user-supplied MemoryBlock, this will trim any excess capacity off the block, so that its length matches the amount of actual data that has been written so far. More...
const void *	getData () const noexcept
	Returns a pointer to the data that has been written to the stream. More...
size_t	getDataSize () const noexcept
	Returns the number of bytes of data that have been written to the stream. More...
MemoryBlock	getMemoryBlock () const
	Returns a copy of the stream's data as a memory block. More...
const String &	getNewLineString () const noexcept
	Returns the current new-line string that was set by setNewLineString(). More...
int64	getPosition () override
	Returns the stream's current position. More...
void	preallocate (size_t bytesToPreallocate)
	Increases the internal storage capacity to be able to contain at least the specified amount of data without needing to be resized. More...
void	reset () noexcept
	Resets the stream, clearing any data that has been written to it so far. More...
void	setNewLineString (const String &newLineString)
	Sets the string to write to the stream when a new line is written. More...
bool	setPosition (int64) override
	Tries to move the stream's output position. More...
String	toString () const
	Attempts to detect the encoding of the data and convert it to a string. More...
String	toUTF8 () const
	Returns a String created from the (UTF8) data that has been written to the stream. More...
bool	write (const void *, size_t) override
	Writes a block of data to the stream. More...
virtual bool	writeBool (bool boolValue)
	Writes a boolean to the stream as a single byte. More...
virtual bool	writeByte (char byte)
	Writes a single byte to the stream. More...
virtual bool	writeCompressedInt (int value)
	Writes a condensed binary encoding of a 32-bit integer. More...
virtual bool	writeDouble (double value)
	Writes a 64-bit floating point value to the stream in a binary format. More...
virtual bool	writeDoubleBigEndian (double value)
	Writes a 64-bit floating point value to the stream in a binary format. More...
virtual bool	writeFloat (float value)
	Writes a 32-bit floating point value to the stream in a binary format. More...
virtual bool	writeFloatBigEndian (float value)
	Writes a 32-bit floating point value to the stream in a binary format. More...
int64	writeFromInputStream (InputStream &, int64 maxNumBytesToWrite) override
	Reads data from an input stream and writes it to this stream. More...
virtual bool	writeInt (int value)
	Writes a 32-bit integer to the stream in a little-endian byte order. More...
virtual bool	writeInt64 (int64 value)
	Writes a 64-bit integer to the stream in a little-endian byte order. More...
virtual bool	writeInt64BigEndian (int64 value)
	Writes a 64-bit integer to the stream in a big-endian byte order. More...
virtual bool	writeIntBigEndian (int value)
	Writes a 32-bit integer to the stream in a big-endian byte order. More...
bool	writeRepeatedByte (uint8 byte, size_t numTimesToRepeat) override
	Writes a byte to the output stream a given number of times. More...
virtual bool	writeShort (short value)
	Writes a 16-bit integer to the stream in a little-endian byte order. More...
virtual bool	writeShortBigEndian (short value)
	Writes a 16-bit integer to the stream in a big-endian byte order. More...
virtual bool	writeString (const String &text)
	Stores a string in the stream in a binary format. More...
virtual bool	writeText (const String &text, bool asUTF16, bool writeUTF16ByteOrderMark, const char *lineEndings)
	Writes a string of text to the stream. More...

Private Member Functions
char *	prepareToWrite (size_t)
void	trimExternalBlockSize ()

Private Attributes
size_t	availableSize = 0
MemoryBlock *const	blockToUse = nullptr
void *	externalData = nullptr
MemoryBlock	internalBlock
String	newLineString
size_t	position = 0
size_t	size = 0

Detailed Description

Writes data to an internal memory buffer, which grows as required.

The data that was written into the stream can then be accessed later as a contiguous block of memory.

@tags{Core}

Constructor & Destructor Documentation

MemoryOutputStream() [1/3]

juce::MemoryOutputStream::MemoryOutputStream

(

size_t

initialSize = 256

)

Creates an empty memory stream, ready to be written into.

Parameters

initialSize

the initial amount of capacity to allocate for writing into

MemoryOutputStream() [2/3]

juce::MemoryOutputStream::MemoryOutputStream	(	MemoryBlock &	memoryBlockToWriteTo,
		bool	appendToExistingBlockContent
	)

Creates a memory stream for writing into into a pre-existing MemoryBlock object.

Note that the destination block will always be larger than the amount of data that has been written to the stream, because the MemoryOutputStream keeps some spare capacity at its end. To trim the block's size down to fit the actual data, call flush(), or delete the MemoryOutputStream.

Parameters

memoryBlockToWriteTo	the block into which new data will be written.
appendToExistingBlockContent	if this is true, the contents of the block will be kept, and new data will be appended to it. If false, the block will be cleared before use

MemoryOutputStream() [3/3]

juce::MemoryOutputStream::MemoryOutputStream	(	void *	destBuffer,
		size_t	destBufferSize
	)

Creates a MemoryOutputStream that will write into a user-supplied, fixed-size block of memory.

When using this mode, the stream will write directly into this memory area until it's full, at which point write operations will fail.

~MemoryOutputStream()

juce::MemoryOutputStream::~MemoryOutputStream ( )

override

Destructor.

This will free any data that was written to it.

Member Function Documentation

appendUTF8Char()

bool juce::MemoryOutputStream::appendUTF8Char

(

juce_wchar

character

)

Appends the utf-8 bytes for a unicode character.

flush()

void juce::MemoryOutputStream::flush ( )

overridevirtual

If the stream is writing to a user-supplied MemoryBlock, this will trim any excess capacity off the block, so that its length matches the amount of actual data that has been written so far.

Implements juce::OutputStream.

getData()

const void* juce::MemoryOutputStream::getData ( ) const

noexcept

Returns a pointer to the data that has been written to the stream.

See also

getDataSize

getDataSize()

size_t juce::MemoryOutputStream::getDataSize ( ) const

inlinenoexcept

Returns the number of bytes of data that have been written to the stream.

See also

getData

References juce::gl::size.

getMemoryBlock()

MemoryBlock juce::MemoryOutputStream::getMemoryBlock

(

)

const

Returns a copy of the stream's data as a memory block.

getNewLineString()

const String& juce::OutputStream::getNewLineString ( ) const

inlinenoexceptinherited

Returns the current new-line string that was set by setNewLineString().

getPosition()

int64 juce::MemoryOutputStream::getPosition ( )

inlineoverridevirtual

Returns the stream's current position.

See also

setPosition

Implements juce::OutputStream.

preallocate()

void juce::MemoryOutputStream::preallocate

(

size_t

bytesToPreallocate

)

Increases the internal storage capacity to be able to contain at least the specified amount of data without needing to be resized.

prepareToWrite()

char* juce::MemoryOutputStream::prepareToWrite ( size_t  )

private

reset()

void juce::MemoryOutputStream::reset ( )

noexcept

Resets the stream, clearing any data that has been written to it so far.

setNewLineString()

void juce::OutputStream::setNewLineString ( const String &  newLineString )

inherited

Sets the string to write to the stream when a new line is written.

By default this will be set the value of NewLine::getDefault().

setPosition()

bool juce::MemoryOutputStream::setPosition ( int64  newPosition )

overridevirtual

Tries to move the stream's output position.

Not all streams will be able to seek to a new position - this will return false if it fails to work.

See also

getPosition

Implements juce::OutputStream.

toString()

String juce::MemoryOutputStream::toString

(

)

const

Attempts to detect the encoding of the data and convert it to a string.

See also

String::createStringFromData

Referenced by juce::CppTokeniserFunctions::addEscapeChars().

toUTF8()

String juce::MemoryOutputStream::toUTF8

(

)

const

Returns a String created from the (UTF8) data that has been written to the stream.

trimExternalBlockSize()

void juce::MemoryOutputStream::trimExternalBlockSize ( )

private

write()

bool juce::MemoryOutputStream::write ( const void *  dataToWrite, size_t  numberOfBytes  )

overridevirtual

Writes a block of data to the stream.

When creating a subclass of OutputStream, this is the only write method that needs to be overloaded - the base class has methods for writing other types of data which use this to do the work.

Parameters

dataToWrite	the target buffer to receive the data. This must not be null.
numberOfBytes	the number of bytes to write.

Returns

false if the write operation fails for some reason

Implements juce::OutputStream.

writeBool()

virtual bool juce::OutputStream::writeBool ( bool  boolValue )

virtualinherited

Writes a boolean to the stream as a single byte.

This is encoded as a binary byte (not as text) with a value of 1 or 0.

Returns

false if the write operation fails for some reason

See also

InputStream::readBool

writeByte()

virtual bool juce::OutputStream::writeByte ( char  byte )

virtualinherited

Writes a single byte to the stream.

Returns

false if the write operation fails for some reason

See also

InputStream::readByte

writeCompressedInt()

virtual bool juce::OutputStream::writeCompressedInt ( int  value )

virtualinherited

Writes a condensed binary encoding of a 32-bit integer.

If you're storing a lot of integers which are unlikely to have very large values, this can save a lot of space, because values under 0xff will only take up 2 bytes, under 0xffff only 3 bytes, etc.

The format used is: number of significant bytes + up to 4 bytes in little-endian order.

Returns

false if the write operation fails for some reason

See also

InputStream::readCompressedInt

writeDouble()

virtual bool juce::OutputStream::writeDouble ( double  value )

virtualinherited

Writes a 64-bit floating point value to the stream in a binary format.

The eight raw bytes of the double value are written out as a little-endian 64-bit int.

Returns

false if the write operation fails for some reason

See also

InputStream::readDouble

writeDoubleBigEndian()

virtual bool juce::OutputStream::writeDoubleBigEndian ( double  value )

virtualinherited

Writes a 64-bit floating point value to the stream in a binary format.

The eight raw bytes of the double value are written out as a big-endian 64-bit int.

See also

InputStream::readDoubleBigEndian

Returns

false if the write operation fails for some reason

writeFloat()

virtual bool juce::OutputStream::writeFloat ( float  value )

virtualinherited

Writes a 32-bit floating point value to the stream in a binary format.

The binary 32-bit encoding of the float is written as a little-endian int.

Returns

false if the write operation fails for some reason

See also

InputStream::readFloat

writeFloatBigEndian()

virtual bool juce::OutputStream::writeFloatBigEndian ( float  value )

virtualinherited

Writes a 32-bit floating point value to the stream in a binary format.

The binary 32-bit encoding of the float is written as a big-endian int.

Returns

false if the write operation fails for some reason

See also

InputStream::readFloatBigEndian

writeFromInputStream()

int64 juce::MemoryOutputStream::writeFromInputStream ( InputStream &  source, int64  maxNumBytesToWrite  )

overridevirtual

Reads data from an input stream and writes it to this stream.

Parameters

source	the stream to read from
maxNumBytesToWrite	the number of bytes to read from the stream (if this is less than zero, it will keep reading until the input is exhausted)

Returns

the number of bytes written

Reimplemented from juce::OutputStream.

writeInt()

virtual bool juce::OutputStream::writeInt ( int  value )

virtualinherited

Writes a 32-bit integer to the stream in a little-endian byte order.

Returns

false if the write operation fails for some reason

See also

InputStream::readInt

writeInt64()

virtual bool juce::OutputStream::writeInt64 ( int64  value )

virtualinherited

Writes a 64-bit integer to the stream in a little-endian byte order.

Returns

false if the write operation fails for some reason

See also

InputStream::readInt64

writeInt64BigEndian()

virtual bool juce::OutputStream::writeInt64BigEndian ( int64  value )

virtualinherited

Writes a 64-bit integer to the stream in a big-endian byte order.

Returns

false if the write operation fails for some reason

See also

InputStream::readInt64BigEndian

writeIntBigEndian()

virtual bool juce::OutputStream::writeIntBigEndian ( int  value )

virtualinherited

Writes a 32-bit integer to the stream in a big-endian byte order.

Returns

false if the write operation fails for some reason

See also

InputStream::readIntBigEndian

writeRepeatedByte()

bool juce::MemoryOutputStream::writeRepeatedByte ( uint8  byte, size_t  numTimesToRepeat  )

overridevirtual

Writes a byte to the output stream a given number of times.

Returns

false if the write operation fails for some reason

Reimplemented from juce::OutputStream.

writeShort()

virtual bool juce::OutputStream::writeShort ( short  value )

virtualinherited

Writes a 16-bit integer to the stream in a little-endian byte order.

This will write two bytes to the stream: (value & 0xff), then (value >> 8).

Returns

false if the write operation fails for some reason

See also

InputStream::readShort

writeShortBigEndian()

virtual bool juce::OutputStream::writeShortBigEndian ( short  value )

virtualinherited

Writes a 16-bit integer to the stream in a big-endian byte order.

This will write two bytes to the stream: (value >> 8), then (value & 0xff).

Returns

false if the write operation fails for some reason

See also

InputStream::readShortBigEndian

writeString()

virtual bool juce::OutputStream::writeString ( const String &  text )

virtualinherited

Stores a string in the stream in a binary format.

This isn't the method to use if you're trying to append text to the end of a text-file! It's intended for storing a string so that it can be retrieved later by InputStream::readString().

It writes the string to the stream as UTF8, including the null termination character.

For appending text to a file, instead use writeText, or operator<<

Returns

false if the write operation fails for some reason

See also

InputStream::readString, writeText, operator<<

writeText()

virtual bool juce::OutputStream::writeText ( const String &  text, bool  asUTF16, bool  writeUTF16ByteOrderMark, const char *  lineEndings  )

virtualinherited

Writes a string of text to the stream.

It can either write the text as UTF-8 or UTF-16, and can also add the UTF-16 byte-order-mark bytes (0xff, 0xfe) to indicate the endianness (these should only be used at the start of a file).

If lineEndings is nullptr, then line endings in the text won't be modified. If you pass "\\n" or "\\r\\n" then this function will replace any existing line feeds.

Returns

false if the write operation fails for some reason

Member Data Documentation

availableSize

size_t juce::MemoryOutputStream::availableSize = 0

private

blockToUse

MemoryBlock* const juce::MemoryOutputStream::blockToUse = nullptr

private

externalData

void* juce::MemoryOutputStream::externalData = nullptr

private

internalBlock

MemoryBlock juce::MemoryOutputStream::internalBlock

private

newLineString

String juce::OutputStream::newLineString

privateinherited

position

size_t juce::MemoryOutputStream::position = 0

private

size

size_t juce::MemoryOutputStream::size = 0

private

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The documentation for this class was generated from the following file:

• juce_MemoryOutputStream.h