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InputStream Class Referenceabstract

The base class for streams that read data. More...

Inherited by BufferedInputStream, FileInputStream, GZIPDecompressorInputStream, MemoryInputStream, and SubregionStream.

Public Member Functions

virtual ~InputStream ()
 Destructor.
 
virtual int64 getTotalLength ()=0
 Returns the total number of bytes available for reading in this stream.
 
int64 getNumBytesRemaining ()
 Returns the number of bytes available for reading, or a negative value if the remaining length is not known.
 
virtual bool isExhausted ()=0
 Returns true if the stream has no more data to read.
 
virtual int read (void *destBuffer, int maxBytesToRead)=0
 Reads some data from the stream into a memory buffer.
 
virtual char readByte ()
 Reads a byte from the stream.
 
virtual bool readBool ()
 Reads a boolean from the stream.
 
virtual short readShort ()
 Reads two bytes from the stream as a little-endian 16-bit value.
 
virtual short readShortBigEndian ()
 Reads two bytes from the stream as a little-endian 16-bit value.
 
virtual int readInt ()
 Reads four bytes from the stream as a little-endian 32-bit value.
 
virtual int readIntBigEndian ()
 Reads four bytes from the stream as a big-endian 32-bit value.
 
virtual int64 readInt64 ()
 Reads eight bytes from the stream as a little-endian 64-bit value.
 
virtual int64 readInt64BigEndian ()
 Reads eight bytes from the stream as a big-endian 64-bit value.
 
virtual float readFloat ()
 Reads four bytes as a 32-bit floating point value.
 
virtual float readFloatBigEndian ()
 Reads four bytes as a 32-bit floating point value.
 
virtual double readDouble ()
 Reads eight bytes as a 64-bit floating point value.
 
virtual double readDoubleBigEndian ()
 Reads eight bytes as a 64-bit floating point value.
 
virtual int readCompressedInt ()
 Reads an encoded 32-bit number from the stream using a space-saving compressed format.
 
virtual String readNextLine ()
 Reads a UTF-8 string from the stream, up to the next linefeed or carriage return.
 
virtual String readString ()
 Reads a zero-terminated UTF-8 string from the stream.
 
virtual String readEntireStreamAsString ()
 Tries to read the whole stream and turn it into a string.
 
virtual int readIntoMemoryBlock (MemoryBlock &destBlock, ssize_t maxNumBytesToRead=-1)
 Reads from the stream and appends the data to a MemoryBlock.
 
virtual int64 getPosition ()=0
 Returns the offset of the next byte that will be read from the stream.
 
virtual bool setPosition (int64 newPosition)=0
 Tries to move the current read position of the stream.
 
virtual void skipNextBytes (int64 numBytesToSkip)
 Reads and discards a number of bytes from the stream.
 

Protected Member Functions

 InputStream () noexcept
 

Detailed Description

The base class for streams that read data.

Input and output streams are used throughout the library - subclasses can override some or all of the virtual functions to implement their behaviour.

See Also
OutputStream, MemoryInputStream, BufferedInputStream, FileInputStream

Constructor & Destructor Documentation

virtual InputStream::~InputStream ( )
virtual

Destructor.

InputStream::InputStream ( )
protectednoexcept

Member Function Documentation

virtual int64 InputStream::getTotalLength ( )
pure virtual

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

Implemented in MemoryInputStream, FileInputStream, GZIPDecompressorInputStream, SubregionStream, and BufferedInputStream.

int64 InputStream::getNumBytesRemaining ( )

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

See Also
getTotalLength
virtual bool InputStream::isExhausted ( )
pure virtual

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

Implemented in MemoryInputStream, FileInputStream, BufferedInputStream, SubregionStream, and GZIPDecompressorInputStream.

virtual int InputStream::read ( void *  destBuffer,
int  maxBytesToRead 
)
pure virtual

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

Implemented in MemoryInputStream, GZIPDecompressorInputStream, FileInputStream, SubregionStream, and BufferedInputStream.

virtual char InputStream::readByte ( )
virtual

Reads a byte from the stream.

If the stream is exhausted, this will return zero.

See Also
OutputStream::writeByte
virtual bool InputStream::readBool ( )
virtual

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
virtual short InputStream::readShort ( )
virtual

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
virtual short InputStream::readShortBigEndian ( )
virtual

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
virtual int InputStream::readInt ( )
virtual

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
virtual int InputStream::readIntBigEndian ( )
virtual

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
virtual int64 InputStream::readInt64 ( )
virtual

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
virtual int64 InputStream::readInt64BigEndian ( )
virtual

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
virtual float InputStream::readFloat ( )
virtual

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
virtual float InputStream::readFloatBigEndian ( )
virtual

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
virtual double InputStream::readDouble ( )
virtual

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
virtual double InputStream::readDoubleBigEndian ( )
virtual

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
virtual int InputStream::readCompressedInt ( )
virtual

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()
virtual String InputStream::readNextLine ( )
virtual

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.

virtual String InputStream::readString ( )
virtual

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.

virtual String InputStream::readEntireStreamAsString ( )
virtual

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 either UTF-16 or UTF-8 formats.

virtual int InputStream::readIntoMemoryBlock ( MemoryBlock destBlock,
ssize_t  maxNumBytesToRead = -1 
)
virtual

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
virtual int64 InputStream::getPosition ( )
pure virtual

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

See Also
setPosition

Implemented in MemoryInputStream, FileInputStream, SubregionStream, BufferedInputStream, and GZIPDecompressorInputStream.

virtual bool InputStream::setPosition ( int64  newPosition)
pure virtual

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

Implemented in MemoryInputStream, FileInputStream, SubregionStream, BufferedInputStream, and GZIPDecompressorInputStream.

virtual void InputStream::skipNextBytes ( int64  numBytesToSkip)
virtual

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.


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