juce::FileOutputStream Class Reference

An output stream that writes into a local file. More...

#include <juce_FileOutputStream.h>

Inheritance diagram for juce::FileOutputStream:

Collaboration diagram for juce::FileOutputStream:

Public Member Functions
	FileOutputStream (const File &fileToWriteTo, size_t bufferSizeToUse=16384)
	Creates a FileOutputStream. More...
	~FileOutputStream () override
	Destructor. More...
bool	failedToOpen () const noexcept
	Returns true if the stream couldn't be opened for some reason. More...
void	flush () override
	If the stream is using a buffer, this will ensure it gets written out to the destination. More...
const File &	getFile () const
	Returns the file that this stream is writing to. 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...
const Result &	getStatus () const noexcept
	Returns the status of the file stream. More...
bool	openedOk () const noexcept
	Returns true if the stream opened without problems. 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...
Result	truncate ()
	Attempts to truncate the file to the current write position. 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...
virtual int64	writeFromInputStream (InputStream &source, int64 maxNumBytesToWrite)
	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
void	closeHandle ()
bool	flushBuffer ()
void	flushInternal ()
void	openHandle ()
int64	setPositionInternal (int64)
ssize_t	writeInternal (const void *, size_t)

Private Attributes
HeapBlock< char >	buffer
size_t	bufferSize
size_t	bytesInBuffer = 0
int64	currentPosition = 0
File	file
void *	fileHandle = nullptr
String	newLineString
Result	status { Result::ok() }

Detailed Description

An output stream that writes into a local file.

See also

OutputStream, FileInputStream, File::createOutputStream

@tags{Core}

Constructor & Destructor Documentation

FileOutputStream()

juce::FileOutputStream::FileOutputStream	(	const File &	fileToWriteTo,
		size_t	bufferSizeToUse = 16384
	)

Creates a FileOutputStream.

If the file doesn't exist, it will first be created. If the file can't be created or opened (for example, because the parent directory of the file does not exist), the failedToOpen() method will return true.

If the file already exists when opened, the stream's write-position will be set to the end of the file. To overwrite an existing file, you can truncate it like this:

FileOutputStream stream (file);
 
if (stream.openedOk())
{
    stream.setPosition (0);
    stream.truncate();
    ...
}

Destroying a FileOutputStream object does not force the operating system to write the buffered data to disk immediately. If this is required you should call flush() before triggering the destructor.

See also

TemporaryFile

~FileOutputStream()

juce::FileOutputStream::~FileOutputStream ( )

override

Destructor.

Member Function Documentation

closeHandle()

void juce::FileOutputStream::closeHandle ( )

private

References fileHandle, and juce::anonymous_namespace{juce_posix_SharedCode.h}::getFD().

failedToOpen()

bool juce::FileOutputStream::failedToOpen ( ) const

inlinenoexcept

Returns true if the stream couldn't be opened for some reason.

See also

getResult()

flush()

void juce::FileOutputStream::flush ( )

overridevirtual

If the stream is using a buffer, this will ensure it gets written out to the destination.

Implements juce::OutputStream.

Referenced by truncate().

flushBuffer()

bool juce::FileOutputStream::flushBuffer ( )

private

flushInternal()

void juce::FileOutputStream::flushInternal ( )

private

getFile()

const File& juce::FileOutputStream::getFile ( ) const

inline

Returns the file that this stream is writing to.

getNewLineString()

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

inlinenoexceptinherited

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

getPosition()

int64 juce::FileOutputStream::getPosition ( )

overridevirtual

Returns the stream's current position.

See also

setPosition

Implements juce::OutputStream.

getStatus()

const Result& juce::FileOutputStream::getStatus ( ) const

inlinenoexcept

Returns the status of the file stream.

The result will be ok if the file opened successfully. If an error occurs while opening or writing to the file, this will contain an error message.

openedOk()

bool juce::FileOutputStream::openedOk ( ) const

inlinenoexcept

Returns true if the stream opened without problems.

See also

getResult()

openHandle()

void juce::FileOutputStream::openHandle ( )

private

References currentPosition, juce::File::exists(), juce::gl::f, juce::anonymous_namespace{juce_posix_SharedCode.h}::fdToVoidPointer(), file, fileHandle, juce::File::getFullPathName(), juce::anonymous_namespace{juce_posix_SharedCode.h}::getResultForErrno(), status, and juce::String::toUTF8().

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::FileOutputStream::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.

setPositionInternal()

int64 juce::FileOutputStream::setPositionInternal ( int64  )

private

truncate()

Result juce::FileOutputStream::truncate

(

)

Attempts to truncate the file to the current write position.

To truncate a file to a specific size, first use setPosition() to seek to the appropriate location, and then call this method.

References currentPosition, fileHandle, flush(), juce::anonymous_namespace{juce_posix_SharedCode.h}::getFD(), juce::anonymous_namespace{juce_posix_SharedCode.h}::getResultForReturnValue(), and status.

write()

bool juce::FileOutputStream::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.

Referenced by writeInternal().

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()

virtual int64 juce::OutputStream::writeFromInputStream ( InputStream &  source, int64  maxNumBytesToWrite  )

virtualinherited

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 in juce::MemoryOutputStream.

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

writeInternal()

ssize_t juce::FileOutputStream::writeInternal ( const void *  data, size_t  numBytes  )

private

References juce::gl::data, fileHandle, juce::anonymous_namespace{juce_posix_SharedCode.h}::getFD(), juce::anonymous_namespace{juce_posix_SharedCode.h}::getResultForErrno(), juce::gl::result, status, and write().

writeRepeatedByte()

bool juce::FileOutputStream::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

buffer

HeapBlock<char> juce::FileOutputStream::buffer

private

bufferSize

size_t juce::FileOutputStream::bufferSize

private

bytesInBuffer

size_t juce::FileOutputStream::bytesInBuffer = 0

private

currentPosition

int64 juce::FileOutputStream::currentPosition = 0

private

Referenced by openHandle(), and truncate().

file

File juce::FileOutputStream::file

private

Referenced by openHandle().

fileHandle

void* juce::FileOutputStream::fileHandle = nullptr

private

Referenced by closeHandle(), openHandle(), truncate(), and writeInternal().

newLineString

String juce::OutputStream::newLineString

privateinherited

status

Result juce::FileOutputStream::status { Result::ok() }

private

Referenced by openHandle(), truncate(), and writeInternal().

---

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

• juce_FileOutputStream.h
• juce_posix_SharedCode.h