juce::MemoryInputStream Class Reference

Allows a block of data to be accessed as a stream. More...

#include <juce_MemoryInputStream.h>

Inheritance diagram for juce::MemoryInputStream:

Collaboration diagram for juce::MemoryInputStream:

Public Member Functions
	MemoryInputStream (const MemoryBlock &data, bool keepInternalCopyOfData)
	Creates a MemoryInputStream. More...
	MemoryInputStream (const void *sourceData, size_t sourceDataSize, bool keepInternalCopyOfData)
	Creates a MemoryInputStream. More...
	MemoryInputStream (MemoryBlock &&blockToTake)
	Creates a stream by moving from a MemoryBlock. More...
	~MemoryInputStream () override
	Destructor. More...
const void *	getData () const noexcept
	Returns a pointer to the source data block from which this stream is reading. More...
size_t	getDataSize () const noexcept
	Returns the number of bytes of source data in the block from which this stream is reading. More...
int64	getNumBytesRemaining ()
	Returns the number of bytes available for reading, or a negative value if the remaining length is not known. More...
int64	getPosition () override
	Returns the offset of the next byte that will be read from the stream. More...
int64	getTotalLength () override
	Returns the total number of bytes available for reading in this stream. More...
bool	isExhausted () override
	Returns true if the stream has no more data to read. More...
int	read (void *destBuffer, int maxBytesToRead) override
	Reads some data from the stream into a memory buffer. More...
ssize_t	read (void *destBuffer, size_t maxBytesToRead)
virtual bool	readBool ()
	Reads a boolean from the stream. More...
virtual char	readByte ()
	Reads a byte from the stream. More...
virtual int	readCompressedInt ()
	Reads an encoded 32-bit number from the stream using a space-saving compressed format. More...
virtual double	readDouble ()
	Reads eight bytes as a 64-bit floating point value. More...
virtual double	readDoubleBigEndian ()
	Reads eight bytes as a 64-bit floating point value. More...
virtual String	readEntireStreamAsString ()
	Tries to read the whole stream and turn it into a string. More...
virtual float	readFloat ()
	Reads four bytes as a 32-bit floating point value. More...
virtual float	readFloatBigEndian ()
	Reads four bytes as a 32-bit floating point value. More...
virtual int	readInt ()
	Reads four bytes from the stream as a little-endian 32-bit value. More...
virtual int64	readInt64 ()
	Reads eight bytes from the stream as a little-endian 64-bit value. More...
virtual int64	readInt64BigEndian ()
	Reads eight bytes from the stream as a big-endian 64-bit value. More...
virtual int	readIntBigEndian ()
	Reads four bytes from the stream as a big-endian 32-bit value. More...
virtual size_t	readIntoMemoryBlock (MemoryBlock &destBlock, ssize_t maxNumBytesToRead=-1)
	Reads from the stream and appends the data to a MemoryBlock. More...
virtual String	readNextLine ()
	Reads a UTF-8 string from the stream, up to the next linefeed or carriage return. More...
virtual short	readShort ()
	Reads two bytes from the stream as a little-endian 16-bit value. More...
virtual short	readShortBigEndian ()
	Reads two bytes from the stream as a little-endian 16-bit value. More...
virtual String	readString ()
	Reads a zero-terminated UTF-8 string from the stream. More...
bool	setPosition (int64) override
	Tries to move the current read position of the stream. More...
void	skipNextBytes (int64 numBytesToSkip) override
	Reads and discards a number of bytes from the stream. More...

Private Attributes
const void *	data
size_t	dataSize
MemoryBlock	internalCopy
size_t	position = 0

Detailed Description

Allows a block of data to be accessed as a stream.

This can either be used to refer to a shared block of memory, or can make its own internal copy of the data when the MemoryInputStream is created.

@tags{Core}

Constructor & Destructor Documentation

MemoryInputStream() [1/3]

juce::MemoryInputStream::MemoryInputStream	(	const void *	sourceData,
		size_t	sourceDataSize,
		bool	keepInternalCopyOfData
	)

Creates a MemoryInputStream.

Parameters

sourceData	the block of data to use as the stream's source
sourceDataSize	the number of bytes in the source data block
keepInternalCopyOfData	if false, the stream will just keep a pointer to the source data, so this data shouldn't be changed for the lifetime of the stream; if this parameter is true, the stream will make its own copy of the data and use that.

MemoryInputStream() [2/3]

juce::MemoryInputStream::MemoryInputStream	(	const MemoryBlock &	data,
		bool	keepInternalCopyOfData
	)

Creates a MemoryInputStream.

Parameters

data	a block of data to use as the stream's source
keepInternalCopyOfData	if false, the stream will just keep a reference to the source data, so this data shouldn't be changed for the lifetime of the stream; if this parameter is true, the stream will make its own copy of the data and use that.

MemoryInputStream() [3/3]

juce::MemoryInputStream::MemoryInputStream

(

MemoryBlock &&

blockToTake

)

Creates a stream by moving from a MemoryBlock.

~MemoryInputStream()

juce::MemoryInputStream::~MemoryInputStream ( )

override

Destructor.

Member Function Documentation

getData()

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

inlinenoexcept

Returns a pointer to the source data block from which this stream is reading.

References juce::gl::data.

getDataSize()

size_t juce::MemoryInputStream::getDataSize ( ) const

inlinenoexcept

Returns the number of bytes of source data in the block from which this stream is reading.

References juce::gl::dataSize.

getNumBytesRemaining()

int64 juce::InputStream::getNumBytesRemaining ( )

inherited

Returns the number of bytes available for reading, or a negative value if the remaining length is not known.

See also

getTotalLength

getPosition()

int64 juce::MemoryInputStream::getPosition ( )

overridevirtual

Returns the offset of the next byte that will be read from the stream.

See also

setPosition

Implements juce::InputStream.

getTotalLength()

int64 juce::MemoryInputStream::getTotalLength ( )

overridevirtual

Returns the total number of bytes available for reading in this stream.

Note that this is the number of bytes available from the start of the stream, not from the current position.

If the size of the stream isn't actually known, this will return -1.

See also

getNumBytesRemaining

Implements juce::InputStream.

isExhausted()

bool juce::MemoryInputStream::isExhausted ( )

overridevirtual

Returns true if the stream has no more data to read.

Implements juce::InputStream.

read() [1/2]

int juce::MemoryInputStream::read ( void *  destBuffer, int  maxBytesToRead  )

overridevirtual

Reads some data from the stream into a memory buffer.

This is the only read method that subclasses actually need to implement, as the InputStream base class implements the other read methods in terms of this one (although it's often more efficient for subclasses to implement them directly).

Parameters

destBuffer	the destination buffer for the data. This must not be null.
maxBytesToRead	the maximum number of bytes to read - make sure the memory block passed in is big enough to contain this many bytes. This value must not be negative.

Returns

the actual number of bytes that were read, which may be less than maxBytesToRead if the stream is exhausted before it gets that far

Implements juce::InputStream.

read() [2/2]

ssize_t juce::InputStream::read ( void *  destBuffer, size_t  maxBytesToRead  )

inherited

readBool()

virtual bool juce::InputStream::readBool ( )

virtualinherited

Reads a boolean from the stream.

The bool is encoded as a single byte - non-zero for true, 0 for false. If the stream is exhausted, this will return false.

See also

OutputStream::writeBool

readByte()

virtual char juce::InputStream::readByte ( )

virtualinherited

Reads a byte from the stream.

If the stream is exhausted, this will return zero.

See also

OutputStream::writeByte

readCompressedInt()

virtual int juce::InputStream::readCompressedInt ( )

virtualinherited

Reads an encoded 32-bit number from the stream using a space-saving compressed format.

For small values, this is more space-efficient than using readInt() and OutputStream::writeInt() The format used is: number of significant bytes + up to 4 bytes in little-endian order.

See also

OutputStream::writeCompressedInt()

readDouble()

virtual double juce::InputStream::readDouble ( )

virtualinherited

Reads eight bytes as a 64-bit floating point value.

The raw 64-bit encoding of the double is read from the stream as a little-endian int64. If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeDouble, readFloat

readDoubleBigEndian()

virtual double juce::InputStream::readDoubleBigEndian ( )

virtualinherited

Reads eight bytes as a 64-bit floating point value.

The raw 64-bit encoding of the double is read from the stream as a big-endian int64. If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeDoubleBigEndian, readFloatBigEndian

readEntireStreamAsString()

virtual String juce::InputStream::readEntireStreamAsString ( )

virtualinherited

Tries to read the whole stream and turn it into a string.

This will read from the stream's current position until the end-of-stream. It can read from UTF-8 data, or UTF-16 if it detects suitable header-bytes.

readFloat()

virtual float juce::InputStream::readFloat ( )

virtualinherited

Reads four bytes as a 32-bit floating point value.

The raw 32-bit encoding of the float is read from the stream as a little-endian int. If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeFloat, readDouble

readFloatBigEndian()

virtual float juce::InputStream::readFloatBigEndian ( )

virtualinherited

Reads four bytes as a 32-bit floating point value.

The raw 32-bit encoding of the float is read from the stream as a big-endian int. If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeFloatBigEndian, readDoubleBigEndian

readInt()

virtual int juce::InputStream::readInt ( )

virtualinherited

Reads four bytes from the stream as a little-endian 32-bit value.

If the next four bytes are byte1 to byte4, this returns (byte1 | (byte2 << 8) | (byte3 << 16) | (byte4 << 24)).

If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeInt, readIntBigEndian

readInt64()

virtual int64 juce::InputStream::readInt64 ( )

virtualinherited

Reads eight bytes from the stream as a little-endian 64-bit value.

If the next eight bytes are byte1 to byte8, this returns (byte1 | (byte2 << 8) | (byte3 << 16) | (byte4 << 24) | (byte5 << 32) | (byte6 << 40) | (byte7 << 48) | (byte8 << 56)).

If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeInt64, readInt64BigEndian

readInt64BigEndian()

virtual int64 juce::InputStream::readInt64BigEndian ( )

virtualinherited

Reads eight bytes from the stream as a big-endian 64-bit value.

If the next eight bytes are byte1 to byte8, this returns (byte8 | (byte7 << 8) | (byte6 << 16) | (byte5 << 24) | (byte4 << 32) | (byte3 << 40) | (byte2 << 48) | (byte1 << 56)).

If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeInt64BigEndian, readInt64

readIntBigEndian()

virtual int juce::InputStream::readIntBigEndian ( )

virtualinherited

Reads four bytes from the stream as a big-endian 32-bit value.

If the next four bytes are byte1 to byte4, this returns (byte4 | (byte3 << 8) | (byte2 << 16) | (byte1 << 24)).

If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeIntBigEndian, readInt

readIntoMemoryBlock()

virtual size_t juce::InputStream::readIntoMemoryBlock ( MemoryBlock &  destBlock, ssize_t  maxNumBytesToRead = -1  )

virtualinherited

Reads from the stream and appends the data to a MemoryBlock.

Parameters

destBlock	the block to append the data onto
maxNumBytesToRead	if this is a positive value, it sets a limit to the number of bytes that will be read - if it's negative, data will be read until the stream is exhausted.

Returns

the number of bytes that were added to the memory block

readNextLine()

virtual String juce::InputStream::readNextLine ( )

virtualinherited

Reads a UTF-8 string from the stream, up to the next linefeed or carriage return.

This will read up to the next "\n" or "\r\n" or end-of-stream.

After this call, the stream's position will be left pointing to the next character following the line-feed, but the linefeeds aren't included in the string that is returned.

readShort()

virtual short juce::InputStream::readShort ( )

virtualinherited

Reads two bytes from the stream as a little-endian 16-bit value.

If the next two bytes read are byte1 and byte2, this returns (byte1 | (byte2 << 8)). If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeShort, readShortBigEndian

readShortBigEndian()

virtual short juce::InputStream::readShortBigEndian ( )

virtualinherited

Reads two bytes from the stream as a little-endian 16-bit value.

If the next two bytes read are byte1 and byte2, this returns (byte2 | (byte1 << 8)). If the stream is exhausted partway through reading the bytes, this will return zero.

See also

OutputStream::writeShortBigEndian, readShort

readString()

virtual String juce::InputStream::readString ( )

virtualinherited

Reads a zero-terminated UTF-8 string from the stream.

This will read characters from the stream until it hits a null character or end-of-stream.

See also

OutputStream::writeString, readEntireStreamAsString

Reimplemented in juce::BufferedInputStream.

setPosition()

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

overridevirtual

Tries to move the current read position of the stream.

The position is an absolute number of bytes from the stream's start.

Some streams might not be able to do this, in which case they should do nothing and return false. Others might be able to manage it by resetting themselves and skipping to the correct position, although this is obviously a bit slow.

Returns

true if the stream manages to reposition itself correctly

See also

getPosition

Implements juce::InputStream.

skipNextBytes()

void juce::MemoryInputStream::skipNextBytes ( int64  numBytesToSkip )

overridevirtual

Reads and discards a number of bytes from the stream.

Some input streams might implement this more efficiently, but the base class will just keep reading data until the requisite number of bytes have been done. For large skips it may be quicker to call setPosition() with the required position.

Reimplemented from juce::InputStream.

Member Data Documentation

data

const void* juce::MemoryInputStream::data

private

dataSize

size_t juce::MemoryInputStream::dataSize

private

internalCopy

MemoryBlock juce::MemoryInputStream::internalCopy

private

position

size_t juce::MemoryInputStream::position = 0

private

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

• juce_MemoryInputStream.h