SubregionStream Class Reference

Wraps another input stream, and reads from a specific part of it. More...

#include <juce_SubregionStream.h>

Inheritance diagram for SubregionStream:

Collaboration diagram for SubregionStream:

Public Member Functions
	SubregionStream (InputStream *sourceStream, int64 startPositionInSourceStream, int64 lengthOfSourceStream, bool deleteSourceWhenDestroyed)
	Creates a SubregionStream from an input source. More...
	~SubregionStream ()
	Destructor. 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...
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 newPosition) override
	Tries to move the current read position of the stream. More...
virtual void	skipNextBytes (int64 numBytesToSkip)
	Reads and discards a number of bytes from the stream. More...

Private Attributes
const int64	lengthOfSourceStream
OptionalScopedPointer< InputStream >	source
const int64	startPositionInSourceStream

Detailed Description

Wraps another input stream, and reads from a specific part of it.

This lets you take a subsection of a stream and present it as an entire stream in its own right.

Constructor & Destructor Documentation

SubregionStream()

SubregionStream::SubregionStream	(	InputStream *	sourceStream,
		int64	startPositionInSourceStream,
		int64	lengthOfSourceStream,
		bool	deleteSourceWhenDestroyed
	)

Creates a SubregionStream from an input source.

Parameters

sourceStream	the source stream to read from
startPositionInSourceStream	this is the position in the source stream that corresponds to position 0 in this stream
lengthOfSourceStream	this specifies the maximum number of bytes from the source stream that will be passed through by this stream. When the position of this stream exceeds lengthOfSourceStream, it will cause an end-of-stream. If the length passed in here is greater than the length of the source stream (as returned by getTotalLength()), then the smaller value will be used. Passing a negative value for this parameter means it will keep reading until the source's end-of-stream.
deleteSourceWhenDestroyed	whether the sourceStream that is passed in should be deleted by this object when it is itself deleted.

~SubregionStream()

SubregionStream::~SubregionStream

(

)

Destructor.

This may also delete the source stream, if that option was chosen when the buffered stream was created.

Member Function Documentation

getNumBytesRemaining()

int64 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 SubregionStream::getPosition ( )

overridevirtual

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

See also

setPosition

Implements InputStream.

getTotalLength()

int64 SubregionStream::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 InputStream.

isExhausted()

bool SubregionStream::isExhausted ( )

overridevirtual

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

Implements InputStream.

read()

int SubregionStream::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 InputStream.

readBool()

virtual bool 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 BufferedInputStream.

setPosition()

bool SubregionStream::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 InputStream.

skipNextBytes()

virtual void InputStream::skipNextBytes ( int64  numBytesToSkip )

virtualinherited

Reads and discards a number of bytes from the stream.

Some input streams might implement this efficiently, but the base class will just keep reading data until the requisite number of bytes have been done.

Member Data Documentation

lengthOfSourceStream

const int64 SubregionStream::lengthOfSourceStream

private

source

OptionalScopedPointer<InputStream> SubregionStream::source

private

startPositionInSourceStream

const int64 SubregionStream::startPositionInSourceStream

private

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

• juce_SubregionStream.h