JUCE  v5.4.1-191-g0ab5e696f
JUCE API
Looking for a senior C++ dev?
I'm looking for work. Hire me!
juce::SubregionStream Class Reference

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

#include <juce_SubregionStream.h>

Inheritance diagram for juce::SubregionStream:
Collaboration diagram for juce::SubregionStream:

Public Member Functions

 SubregionStream (InputStream *sourceStream, int64 startPositionInSourceStream, int64 lengthOfSourceStream, bool deleteSourceWhenDestroyed)
 Creates a SubregionStream from an input source. More...
 
 ~SubregionStream () override
 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< InputStreamsource
 
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.

{Core}

Constructor & Destructor Documentation

◆ SubregionStream()

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

Creates a SubregionStream from an input source.

Parameters
sourceStreamthe source stream to read from
startPositionInSourceStreamthis is the position in the source stream that corresponds to position 0 in this stream
lengthOfSourceStreamthis 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.
deleteSourceWhenDestroyedwhether the sourceStream that is passed in should be deleted by this object when it is itself deleted.

◆ ~SubregionStream()

juce::SubregionStream::~SubregionStream ( )
override

Destructor.

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

Member Function Documentation

◆ 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::SubregionStream::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::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 juce::InputStream.

◆ isExhausted()

bool juce::SubregionStream::isExhausted ( )
overridevirtual

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

Implements juce::InputStream.

◆ read()

int juce::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
destBufferthe destination buffer for the data. This must not be null.
maxBytesToReadthe 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.

◆ 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
destBlockthe block to append the data onto
maxNumBytesToReadif 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::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 juce::InputStream.

◆ skipNextBytes()

virtual void juce::InputStream::skipNextBytes ( int64  numBytesToSkip)
virtualinherited

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 in juce::MemoryInputStream.

Member Data Documentation

◆ lengthOfSourceStream

const int64 juce::SubregionStream::lengthOfSourceStream
private

◆ source

OptionalScopedPointer<InputStream> juce::SubregionStream::source
private

◆ startPositionInSourceStream

const int64 juce::SubregionStream::startPositionInSourceStream
private

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