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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 (size_t initialSize=256)
 Creates an empty memory stream, ready to be written into. More...
 
 MemoryOutputStream (MemoryBlock &memoryBlockToWriteTo, bool appendToExistingBlockContent)
 Creates a memory stream for writing into into a pre-existing MemoryBlock object. 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 StringgetNewLineString () 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
 
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.

{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
initialSizethe 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 capactity at its end. To trim the block's size down to fit the actual data, call flush(), or delete the MemoryOutputStream.

Parameters
memoryBlockToWriteTothe block into which new data will be written.
appendToExistingBlockContentif 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

◆ 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()

◆ 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
dataToWritethe target buffer to receive the data. This must not be null.
numberOfBytesthe 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
sourcethe stream to read from
maxNumBytesToWritethe 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

◆ position

size_t juce::MemoryOutputStream::position = 0
private

◆ size

size_t juce::MemoryOutputStream::size = 0
private

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