Reader class that reads files stored in the HIPO format. More...

#include <Reader.h>

Public Member Functions
	Reader ()
	Default constructor. More...

	Reader (std::string const &filename)
	Constructor with filename. More...

	Reader (std::string const &filename, bool forceScan)
	Constructor with filename. More...

	Reader (std::shared_ptr< ByteBuffer > &buffer, bool checkRecordNumSeq=false)
	Constructor for reading buffer with evio data. More...

	~Reader ()=default

void	open (std::string const &filename, bool scan=true)
	Opens an input stream in binary mode. More...

void	close ()
	This closes the file. More...

bool	isClosed () const
	Has close() been called (without reopening by calling setBuffer(std::shared_ptr<ByteBuffer> &))? More...

bool	isFile () const
	Is a file being read? More...

std::string	getFileName () const
	Get the name of the file being read. More...

size_t	getFileSize () const
	Get the size of the file being read, in bytes. More...

void	setBuffer (std::shared_ptr< ByteBuffer > &buf)
	This method can be used to avoid creating additional Reader objects by reusing this one with another buffer. More...

std::shared_ptr< ByteBuffer >	getBuffer ()
	Get the buffer being read, if any. More...

size_t	getBufferOffset () const
	Get the beginning position of the buffer being read. More...

FileHeader &	getFileHeader ()
	Get the file header from reading a file. More...

std::shared_ptr< RecordHeader > &	getFirstRecordHeader ()
	Get the first record header from reading a file/buffer. More...

ByteOrder &	getByteOrder ()
	Get the byte order of the file/buffer being read. More...

uint32_t	getVersion () const
	Get the Evio format version number of the file/buffer being read. More...

bool	isCompressed () const
	Is the data in the file/buffer compressed? More...

bool	isEvioFormat () const
	Does this file/buffer contain non-evio format events? More...

std::string	getDictionary ()
	Get the XML format dictionary if there is one. More...

bool	hasDictionary () const
	Does this evio file/buffer have an associated XML dictionary? More...

std::shared_ptr< uint8_t > &	getFirstEvent (uint32_t *size)
	Get a byte array representing the first event. More...

uint32_t	getFirstEventSize ()
	Get size, in bytes, of byte array representing the first event. More...

bool	hasFirstEvent () const
	Does this evio file/buffer have an associated first event? More...

uint32_t	getEventCount () const
	Get the number of events in file/buffer. More...

uint32_t	getRecordCount () const
	Get the number of records read from the file/buffer. More...

std::vector< RecordPosition > &	getRecordPositions ()
	Returns a reference to the list of record positions in the file. More...

std::vector< std::shared_ptr < EvioNode > > &	getEventNodes ()
	Get a reference to the list of EvioNode objects contained in the buffer being read. More...

bool	getCheckRecordNumberSequence () const
	Get whether or not record numbers are enforced to be sequential. More...

uint32_t	getNumEventsRemaining () const
	Get the number of events remaining in the file/buffer. More...

std::shared_ptr< uint8_t >	getNextEvent (uint32_t *len)
	Get a byte array representing the next event from the file/buffer while sequentially reading. More...

std::shared_ptr< uint8_t >	getPrevEvent (uint32_t *len)
	Get a byte array representing the previous event from the sequential queue. More...

std::shared_ptr< EvioNode >	getNextEventNode ()
	Get an EvioNode representing the next event from the buffer while sequentially reading. More...

std::shared_ptr< ByteBuffer >	readUserHeader ()
	Reads user header of the file header/first record header of buffer. More...

std::shared_ptr< uint8_t >	getEvent (uint32_t index, uint32_t *len)
	Get a byte array representing the specified event from the file/buffer. More...

ByteBuffer &	getEvent (ByteBuffer &buf, uint32_t index)
	Get a byte array representing the specified event from the file/buffer and place it in the given buf. More...

std::shared_ptr< ByteBuffer >	getEvent (std::shared_ptr< ByteBuffer > &buf, uint32_t index)
	Get a byte array representing the specified event from the file/buffer and place it in the given buf. More...

uint32_t	getEventLength (uint32_t index)
	Returns the length of the event with given index. More...

std::shared_ptr< EvioNode >	getEventNode (uint32_t index)
	Get an EvioNode representing the specified event from the buffer. More...

bool	hasNext () const
	Checks if the file has an event to read next. More...

bool	hasPrev () const
	Checks if the stream has previous event to be accessed through, getPrevEvent() More...

uint32_t	getRecordEventCount () const
	Get the number of events in current record. More...

uint32_t	getCurrentRecord () const
	Get the index of the current record. More...

RecordInput &	getCurrentRecordStream ()
	Get the current record stream. More...

bool	readRecord (uint32_t index)
	Reads record from the file/buffer at the given record index. More...

Protected Member Functions
void	extractDictionaryAndFirstEvent ()
	Extract dictionary and first event from file/buffer if possible, else do nothing. More...

void	extractDictionaryFromBuffer ()
	Extract dictionary and first event from buffer if possible, else do nothing. More...

void	extractDictionaryFromFile ()
	Extract dictionary and first event from file if possible, else do nothing. More...

std::shared_ptr< ByteBuffer >	scanBuffer ()
	This method scans a buffer to find all records and store their position, length, and event count. More...

void	scanUncompressedBuffer ()
	Scan buffer containing uncompressed data to find all records and store their position, length, and event count. More...

void	forceScanFile ()
	Scan file to find all records and store their position, length, and event count. More...

void	scanFile (bool force)
	Scans the file to index all the record positions. More...

std::shared_ptr< ByteBuffer > &	addStructure (uint32_t eventNumber, ByteBuffer &addBuffer)
	This method adds an evio container (bank, segment, or tag segment) as the last structure contained in an event. More...

std::shared_ptr< ByteBuffer > &	removeStructure (std::shared_ptr< EvioNode > &removeNode)
	This method removes the data, represented by the given node, from the buffer. More...

void	show () const
	Print out all record position information. More...

Static Protected Member Functions
static void	findRecordInfo (std::shared_ptr< ByteBuffer > &buf, uint32_t offset, uint32_t *info, uint32_t infoLen)
	Reads data from a record header in order to determine things like the bitInfo word, various lengths, etc. More...

static void	findRecordInfo (ByteBuffer &buf, uint32_t offset, uint32_t *info, uint32_t infoLen)
	Reads data from a record header in order to determine things like the bitInfo word, various lengths, etc. More...

Friends
class	EvioCompactReaderV6

Detailed Description

Reader class that reads files stored in the HIPO format.


File has this structure:

   +----------------------------------+
   |      General File Header         |
   +----------------------------------+
   +----------------------------------+
   |         Index (optional)         |
   +----------------------------------+
   +----------------------------------+
   |     User Header (optional)       |
   +----------------------------------+
   +----------------------------------+
   |                                  |
   |            Record 1              |
   |                                  |
   |                                  |
   |                                  |
   +----------------------------------+
                  ...
   +----------------------------------+
   |                                  |
   |            Record N              |
   |                                  |
   |                                  |
   |                                  |
   +----------------------------------+
   +----------------------------------+
   |       Trailer (optional)         |
   +----------------------------------+
   +----------------------------------+
   |    Trailer's Index (optional)    |
   +----------------------------------+

Buffer or streamed data has this structure:

   +----------------------------------+
   |                                  |
   |            Record 1              |
   |                                  |
   |                                  |
   |                                  |
   +----------------------------------+
                  ...
   +----------------------------------+
   |                                  |
   |            Record N              |
   |                                  |
   |                                  |
   |                                  |
   +----------------------------------+
   +----------------------------------+
   |       Trailer (optional)         |
   +----------------------------------+

The important thing with a buffer or streaming is for the last header or
trailer to set the "last record" bit.

Something to keep in mind is one can intersperse sequential calls (getNextEvent, getPrevEvent, or getNextEventNode) with random access calls (getEvent or getEventNode), and the sequence remains unchanged after the random access.

Version: 6.0

Since: 6.0 08/10/2017

Author: gavalian (original Java); timmer

See Also: FileHeader; RecordInput

Constructor & Destructor Documentation

evio::Reader::Reader ( )

Default constructor.

Does nothing. The open(std::string const &, bool) method has to be called to open the input stream. Also forceScanFile() needs to be called to find records.

evio::Reader::Reader ( std::string const & filename )

explicit

Constructor with filename.

Creates instance and opens the input stream with given name. Uses existing indexes in file before scanning.

Parameters

filename input file name.

Exceptions

IOException	if error reading file
EvioException	if file is not in the proper format or earlier than version 6

References open().

evio::Reader::Reader	(	std::string const &	filename,
		bool	forceScan
	)

Constructor with filename.

Creates instance and opens the input stream with given name.

Parameters

filename	input file name.
forceScan	if true, force a scan of file, else use existing indexes first.

Exceptions

IOException	if error reading file
EvioException	if file is not in the proper format or earlier than version 6

References open(), and scanFile().

evio::Reader::Reader	(	std::shared_ptr< ByteBuffer > &	buffer,
		bool	checkRecordNumSeq = `false`
	)

explicit

Constructor for reading buffer with evio data.

Buffer must be ready to read with position and limit set properly. If the given buffer contains compressed data, it is uncompressed into another buffer. The buffer containing the newly uncompressed data then becomes the internal buffer of this object. It can be obtained by calling getBuffer.

Parameters

buffer	buffer with evio data.
checkRecordNumSeq	if true, check to see if all record numbers are in order, if not throw exception.

Exceptions

EvioException if buffer too small, not in the proper format, or earlier than version 6; if checkRecordNumSeq is true and records are out of sequence.

References scanBuffer().

evio::Reader::~Reader ( )

default

Member Function Documentation

std::shared_ptr< ByteBuffer > & evio::Reader::addStructure	(	uint32_t	eventNumber,
		ByteBuffer &	addBuffer
	)

protected

This method adds an evio container (bank, segment, or tag segment) as the last structure contained in an event.

It is the responsibility of the caller to make sure that the buffer argument contains valid evio data (only data representing the structure to be added - not in file format with record header and the like) which is compatible with the type of data stored in the given event.

To produce such evio data use EvioBank#write(ByteBuffer &), EvioSegment#write(ByteBuffer &) or EvioTagSegment#write(ByteBuffer &) depending on whether a bank, seg, or tagseg is being added.

The given buffer argument must be ready to read with its position and limit defining the limits of the data to copy.

Parameters

eventNumber	number of event to which addBuffer is to be added
addBuffer	buffer containing evio data to add (not evio file format, i.e. no record headers)

Returns: a new ByteBuffer object which is created and filled with all the data including what was just added.

Exceptions

EvioException if eventNumber out of bounds; if addBuffer arg is empty or has non-evio format; if addBuffer is opposite endian to current event buffer; if added data is not the proper length (i.e. multiple of 4 bytes); if the event number does not correspond to an existing event; if there is an internal programming error; if object closed

References evio::ByteBuffer::order(), evio::ByteBuffer::remaining(), scanBuffer(), and evio::RecordHeader::UNCOMPRESSED_LENGTH_OFFSET.

Referenced by evio::EvioCompactReaderV6::addStructure().

void evio::Reader::close ( )

This closes the file.

Referenced by setBuffer().

void evio::Reader::extractDictionaryAndFirstEvent ( )

protected

Extract dictionary and first event from file/buffer if possible, else do nothing.

References extractDictionaryFromBuffer(), and extractDictionaryFromFile().

Referenced by getDictionary(), getFirstEvent(), and getFirstEventSize().

void evio::Reader::extractDictionaryFromBuffer ( )

protected

Extract dictionary and first event from buffer if possible, else do nothing.

References evio::RecordInput::getEvent(), and evio::RecordInput::readRecord().

Referenced by extractDictionaryAndFirstEvent().

void evio::Reader::extractDictionaryFromFile ( )

protected

Extract dictionary and first event from file if possible, else do nothing.

References evio::FileHeader::getByteOrder(), evio::RecordInput::getEvent(), evio::FileHeader::getHeaderLength(), evio::FileHeader::getIndexLength(), evio::FileHeader::getUserHeaderLength(), evio::FileHeader::hasDictionary(), evio::FileHeader::hasFirstEvent(), and evio::RecordInput::readRecord().

Referenced by extractDictionaryAndFirstEvent().

void evio::Reader::findRecordInfo	(	std::shared_ptr< ByteBuffer > &	buf,
		uint32_t	offset,
		uint32_t *	info,
		uint32_t	infoLen
	)

staticprotected

Reads data from a record header in order to determine things like the bitInfo word, various lengths, etc.

Does not change the position or limit of buffer.

Parameters

buf	buffer containing evio header.
offset	byte offset into buffer.
info	array in which to store header info. Elements are: bit info word record length in bytes (inclusive) compression type header length in bytes index array length in bytes user header length in bytes (no padding included) uncompressed data length in bytes (no padding, w/o record header)
infoLen	len in 32-bit words of array at info.

Exceptions

underflow_error	if not enough data in buffer.
EvioException	null info arg or info.length < 7.

void evio::Reader::findRecordInfo	(	ByteBuffer &	buf,
		uint32_t	offset,
		uint32_t *	info,
		uint32_t	infoLen
	)

staticprotected

Reads data from a record header in order to determine things like the bitInfo word, various lengths, etc.

Does not change the position or limit of buffer.

Parameters

buf	buffer containing evio header.
offset	byte offset into buffer.
info	array in which to store header info. Elements are: bit info word record length in bytes (inclusive) compression type header length in bytes index array length in bytes user header length in bytes (no padding included) uncompressed data length in bytes (no padding, w/o record header)
infoLen	len in 32-bit words of array at info.

Exceptions

underflow_error	if not enough data in buffer.
EvioException	null info arg or info.length < 7.

References evio::RecordHeader::BIT_INFO_OFFSET, evio::ByteBuffer::capacity(), evio::RecordHeader::COMPRESSION_TYPE_OFFSET, evio::RecordHeader::EVENT_COUNT_OFFSET, evio::ByteBuffer::getInt(), evio::RecordHeader::HEADER_LENGTH_OFFSET, evio::RecordHeader::INDEX_ARRAY_OFFSET, evio::ByteBuffer::limit(), evio::RecordHeader::RECORD_LENGTH_OFFSET, evio::RecordHeader::UNCOMPRESSED_LENGTH_OFFSET, and evio::RecordHeader::USER_LENGTH_OFFSET.

void evio::Reader::forceScanFile ( )

protected

Scan file to find all records and store their position, length, and event count.

Safe to call this method successively.

Exceptions

IOException	if error reading file
EvioException	if file is not in the proper format or earlier than version 6; if checkRecordNumberSequence is true and records are out of sequence.

References evio::FileEventIndex::addEventSize(), evio::FileEventIndex::clear(), evio::FileHeader::getByteOrder(), evio::RecordHeader::getEntries(), evio::FileHeader::getHeaderLength(), evio::FileHeader::getIndexLength(), evio::RecordHeader::getLength(), evio::RecordHeader::getRecordNumber(), evio::FileHeader::getUserHeaderLength(), evio::FileHeader::getUserHeaderLengthPadding(), evio::FileHeader::getVersion(), evio::RecordHeader::HEADER_SIZE_BYTES, evio::FileHeader::readHeader(), evio::RecordHeader::readHeader(), and evio::Compressor::UNCOMPRESSED.

Referenced by scanFile().

std::shared_ptr< ByteBuffer > evio::Reader::getBuffer ( )

Get the buffer being read, if any.

This may not be the buffer given in the constructor or in setBuffer if the original data was compressed. All data in the returned buffer is uncompressed.

Returns: buffer being read, if any.

Referenced by evio::EvioCompactReaderV6::close(), evio::EvioCompactReaderV6::getByteBuffer(), and evio::EvioCompactReaderV6::toFile().

size_t evio::Reader::getBufferOffset ( ) const

Get the beginning position of the buffer being read.

Returns: the beginning position of the buffer being read.

Referenced by evio::EvioCompactReaderV6::close().

ByteOrder & evio::Reader::getByteOrder ( )

Get the byte order of the file/buffer being read.

Returns: byte order of the file/buffer being read.

Referenced by evio::EvioCompactReaderV6::getByteOrder(), and evio::EvioCompactReaderV6::getFileByteOrder().

bool evio::Reader::getCheckRecordNumberSequence ( ) const

Get whether or not record numbers are enforced to be sequential.

Returns: true

if record numbers are enforced to be sequential.

uint32_t evio::Reader::getCurrentRecord ( ) const

Get the index of the current record.

Returns: index of the current record.

RecordInput & evio::Reader::getCurrentRecordStream ( )

Get the current record stream.

Returns: current record stream.

std::string evio::Reader::getDictionary ( )

Get the XML format dictionary if there is one.

Returns: XML format dictionary, else null.

References extractDictionaryAndFirstEvent().

Referenced by evio::EvioCompactReaderV6::getDictionary(), and evio::EvioCompactReaderV6::getDictionaryXML().

std::shared_ptr< uint8_t > evio::Reader::getEvent	(	uint32_t	index,
		uint32_t *	len
	)

Get a byte array representing the specified event from the file/buffer.

If index is out of bounds, null is returned.

Parameters

index	index of specified event within the entire file/buffer, contiguous starting at 0.
len	pointer to int that gets filled with the returned event's len in bytes.

Returns: byte array representing the specified event or null if index is out of bounds.

Exceptions

EvioException if file/buffer not in hipo format

References evio::RecordInput::getEntries(), evio::RecordInput::getEvent(), evio::FileEventIndex::getMaxEvents(), evio::FileEventIndex::getRecordEventNumber(), evio::FileEventIndex::getRecordNumber(), readRecord(), and evio::FileEventIndex::setEvent().

Referenced by getEvent(), getNextEvent(), and getPrevEvent().

ByteBuffer & evio::Reader::getEvent	(	ByteBuffer &	buf,
		uint32_t	index
	)

Get a byte array representing the specified event from the file/buffer and place it in the given buf.

If no buf is given (arg is null), create a buffer internally and return it. If index is out of bounds, null is returned.

Parameters

buf	buffer in which to place event data.
index	index of specified event within the entire file/buffer, contiguous starting at 0.

Returns: buf.

Exceptions

EvioException if file/buffer not in hipo format, if buf has insufficient space to contain event (buf.capacity() < event size), or index too large.

References evio::RecordInput::getEntries(), evio::RecordInput::getEvent(), evio::FileEventIndex::getMaxEvents(), evio::FileEventIndex::getRecordEventNumber(), evio::FileEventIndex::getRecordNumber(), readRecord(), and evio::FileEventIndex::setEvent().

std::shared_ptr< ByteBuffer > evio::Reader::getEvent	(	std::shared_ptr< ByteBuffer > &	buf,
		uint32_t	index
	)

Get a byte array representing the specified event from the file/buffer and place it in the given buf.

If no buf is given (arg is null), create a buffer internally and return it. If index is out of bounds, null is returned.

Parameters

buf	buffer in which to place event data.
index	index of specified event within the entire file/buffer, contiguous starting at 0.

Returns: buf or null if buf is null.

Exceptions

EvioException if file/buffer not in hipo format, if buf has insufficient space to contain event (buf.capacity() < event size), or index too large.

References getEvent().

uint32_t evio::Reader::getEventCount ( ) const

Get the number of events in file/buffer.

Returns: number of events in file/buffer.

References evio::FileEventIndex::getMaxEvents().

Referenced by evio::EvioCompactReaderV6::getEventCount(), and evio::EvioCompactReaderV6::searchEvent().

uint32_t evio::Reader::getEventLength ( uint32_t index )

Returns the length of the event with given index.

Parameters

index index of the event

Returns: length of the data in bytes or zero if index does not correspond to a valid event.

References evio::RecordInput::getEntries(), evio::RecordInput::getEventLength(), evio::FileEventIndex::getMaxEvents(), evio::FileEventIndex::getRecordEventNumber(), evio::FileEventIndex::getRecordNumber(), readRecord(), and evio::FileEventIndex::setEvent().

std::shared_ptr< EvioNode > evio::Reader::getEventNode ( uint32_t index )

Get an EvioNode representing the specified event from the buffer.

If index is out of bounds, nullptr is returned.

Parameters

index index of specified event within the entire buffer, starting at 0.

Returns: EvioNode representing the specified event or null if index is out of bounds, reading a file or data is compressed.

Exceptions

EvioException index too large or reading from file.

References evio::FileEventIndex::getMaxEvents().

Referenced by evio::EvioCompactReaderV6::getEvent(), evio::EvioCompactReaderV6::getEventBuffer(), and evio::EvioCompactReaderV6::removeEvent().

std::vector< std::shared_ptr< EvioNode > > & evio::Reader::getEventNodes ( )

Get a reference to the list of EvioNode objects contained in the buffer being read.

To be used internally to evio.

Returns: list of EvioNode objects contained in the buffer being read.

FileHeader & evio::Reader::getFileHeader ( )

Get the file header from reading a file.

Returns: file header from reading a file.

std::string evio::Reader::getFileName ( ) const

Get the name of the file being read.

Returns: name of the file being read or null if none.

size_t evio::Reader::getFileSize ( ) const

Get the size of the file being read, in bytes.

Returns: size of the file being read, in bytes, or 0 if none.

Referenced by evio::EvioCompactReaderV6::fileSize().

std::shared_ptr< uint8_t > & evio::Reader::getFirstEvent ( uint32_t * size )

Get a byte array representing the first event.

Parameters

size	pointer filled with the size, in bytes, of the first event (0 if none). If null, this is ignored.

Returns: byte array representing the first event. Null if none.

References extractDictionaryAndFirstEvent().

uint32_t evio::Reader::getFirstEventSize ( )

Get size, in bytes, of byte array representing the first event.

Returns: size, in bytes, of byte array representing the first event. 0 if none.

References extractDictionaryAndFirstEvent().

std::shared_ptr< RecordHeader > & evio::Reader::getFirstRecordHeader ( )

Get the first record header from reading a file/buffer.

Returns: first record header from reading a file/buffer.

Referenced by evio::EvioCompactReaderV6::getFirstBlockHeader().

std::shared_ptr< uint8_t > evio::Reader::getNextEvent ( uint32_t * len )

Get a byte array representing the next event from the file/buffer while sequentially reading.

If the previous call was to getPrevEvent, this will get the event past what that returned. Once the last event is returned, this will return null.

Parameters

len	pointer to int that gets filled with the returned event's len in bytes.

Returns: byte array representing the next event or null if there is none.

Exceptions

EvioException if file/buffer not in hipo format

References getEvent().

std::shared_ptr< EvioNode > evio::Reader::getNextEventNode ( )

Get an EvioNode representing the next event from the buffer while sequentially reading.

Calling this and calling getNextEvent() have the same effect in terms of advancing the same internal counter. If the previous call was to getPrevEvent, this will get the event past what that returned. Once the last event is returned, this will return null.

Returns: EvioNode representing the next event or null if no more events, reading a file or data is compressed.

References evio::FileEventIndex::getMaxEvents().

uint32_t evio::Reader::getNumEventsRemaining ( ) const

Get the number of events remaining in the file/buffer.

Useful only if doing a sequential read.

Returns: number of events remaining in the file/buffer

References evio::FileEventIndex::getMaxEvents().

std::shared_ptr< uint8_t > evio::Reader::getPrevEvent ( uint32_t * len )

Get a byte array representing the previous event from the sequential queue.

If the previous call was to getNextEvent, this will get the event previous to what that returned. If this is called before getNextEvent, it will always return null. Once the first event is returned, this will return null.

Parameters

len	pointer to int that gets filled with the returned event's len in bytes.

Returns: byte array representing the previous event or null if there is none.

Exceptions

EvioException if the file/buffer is not in HIPO format

References getEvent().

uint32_t evio::Reader::getRecordCount ( ) const

Get the number of records read from the file/buffer.

Returns: number of records read from the file/buffer.

Referenced by evio::EvioCompactReaderV6::getBlockCount().

uint32_t evio::Reader::getRecordEventCount ( ) const

Get the number of events in current record.

Returns: number of events in current record.

References evio::RecordInput::getEntries().

std::vector< Reader::RecordPosition > & evio::Reader::getRecordPositions ( )

Returns a reference to the list of record positions in the file.

Returns

uint32_t evio::Reader::getVersion ( ) const

Get the Evio format version number of the file/buffer being read.

Returns: Evio format version number of the file/buffer being read.

Referenced by evio::EvioCompactReaderV6::getEvioVersion().

bool evio::Reader::hasDictionary ( ) const

Does this evio file/buffer have an associated XML dictionary?

Returns: true if this evio file/buffer has an associated XML dictionary, else false.

References evio::FileHeader::hasDictionary().

Referenced by evio::EvioCompactReaderV6::hasDictionary().

bool evio::Reader::hasFirstEvent ( ) const

Does this evio file/buffer have an associated first event?

Returns: true if this evio file/buffer has an associated first event, else false.

References evio::FileHeader::hasFirstEvent().

bool evio::Reader::hasNext ( ) const

Checks if the file has an event to read next.

Returns: true if the next event is available, false otherwise

References evio::FileEventIndex::canAdvance().

bool evio::Reader::hasPrev ( ) const

Checks if the stream has previous event to be accessed through, getPrevEvent()

Returns: true if previous event is accessible, false otherwise

References evio::FileEventIndex::canRetreat().

bool evio::Reader::isClosed ( ) const

Has close() been called (without reopening by calling setBuffer(std::shared_ptr<ByteBuffer> &))?

Returns: true

if this object closed, else
false

.

bool evio::Reader::isCompressed ( ) const

Is the data in the file/buffer compressed?

Returns: true if data is compressed.

Referenced by evio::EvioCompactReaderV6::isCompressed().

bool evio::Reader::isEvioFormat ( ) const

Does this file/buffer contain non-evio format events?

Returns: true if all events are in evio format, else false.

Referenced by evio::EvioCompactReaderV6::EvioCompactReaderV6(), and evio::EvioCompactReaderV6::setBuffer().

bool evio::Reader::isFile ( ) const

Is a file being read?

Returns: true

if a file is being read,
false

if it's a buffer.

Referenced by evio::EvioCompactReaderV6::isFile().

void evio::Reader::open	(	std::string const &	filename,
		bool	scan = `true`
	)

Opens an input stream in binary mode.

Scans for records in the file and stores record information in internal array. Each record can be read from the file.

Parameters

filename	input file name
scan	if true, call scanFile(false).

Exceptions

EvioException if error handling file

References scanFile().

Referenced by evio::EvioCompactReaderV6::EvioCompactReaderV6(), and Reader().

bool evio::Reader::readRecord ( uint32_t index )

Reads record from the file/buffer at the given record index.

Parameters

index record index (starting at 0).

Returns: true if valid index and successful reading record, else false.

Exceptions

EvioException if file/buffer not in hipo format

References evio::RecordInput::readRecord().

Referenced by getEvent(), and getEventLength().

std::shared_ptr< ByteBuffer > evio::Reader::readUserHeader ( )

Reads user header of the file header/first record header of buffer.

The returned ByteBuffer also contains endianness of the file/buffer.

Returns: ByteBuffer containing the user header of the file/buffer.

Exceptions

IOException if error reading file

References evio::FileHeader::getByteOrder(), evio::FileHeader::getHeaderLength(), evio::FileHeader::getIndexLength(), and evio::FileHeader::getUserHeaderLength().

std::shared_ptr< ByteBuffer > & evio::Reader::removeStructure ( std::shared_ptr< EvioNode > & removeNode )

protected

This method removes the data, represented by the given node, from the buffer.

It also marks all nodes taken from that buffer as obsolete. They must not be used anymore.

Parameters

removeNode evio structure to remove from buffer

Returns: ByteBuffer updated to reflect the node removal

Exceptions

EvioException if object closed; if node was not found in any event; if internal programming error; if buffer has compressed data;

References evio::ByteBuffer::limit(), scanBuffer(), evio::Compressor::UNCOMPRESSED, and evio::RecordHeader::UNCOMPRESSED_LENGTH_OFFSET.

Referenced by evio::EvioCompactReaderV6::removeStructure().

std::shared_ptr< ByteBuffer > evio::Reader::scanBuffer ( )

protected

This method scans a buffer to find all records and store their position, length, and event count.

It also finds all events and creates & stores their associated EvioNode objects. The difficulty with doing this is that the buffer may contain compressed data. It must then be uncompressed into a different buffer.

Returns: buffer containing uncompressed data. This buffer is different than the internal buffer. Ready to read.

Exceptions

EvioException	if buffer not in the proper format or earlier than version 6; if checkRecordNumberSequence is true and records are out of sequence.
underflow_error	if not enough data in buffer.

Referenced by addStructure(), Reader(), removeStructure(), and setBuffer().

void evio::Reader::scanFile ( bool force )

protected

Scans the file to index all the record positions.

It takes advantage of any existing indexes in file.

Parameters

force if true, force a file scan even if header or trailer have index info.

Exceptions

IOException	if error reading file
EvioException	if file is not in the proper format or earlier than version 6

Referenced by open(), and Reader().

void evio::Reader::scanUncompressedBuffer ( )

protected

Scan buffer containing uncompressed data to find all records and store their position, length, and event count.

Also finds all events and creates & stores their associated EvioNode objects.

Exceptions

EvioException if buffer too small, not in the proper format, or earlier than version 6; if checkRecordNumberSequence is true and records are out of sequence.

Referenced by scanBuffer().

void evio::Reader::setBuffer ( std::shared_ptr< ByteBuffer > & buf )

This method can be used to avoid creating additional Reader objects by reusing this one with another buffer.

If the given buffer contains compressed data, it is uncompressed into another buffer. The buffer containing the newly uncompressed data then becomes the internal buffer of this object. It can be obtained by calling getBuffer.

Parameters

buf	ByteBuffer to be read

Exceptions

underflow_error	if not enough data in buffer.
EvioException	if buf arg is null, not in the proper format, or earlier than version 6

References evio::FileEventIndex::clear(), close(), and scanBuffer().

Referenced by evio::EvioCompactReaderV6::EvioCompactReaderV6(), and evio::EvioCompactReaderV6::setBuffer().

void evio::Reader::show ( ) const

protected

Print out all record position information.

Friends And Related Function Documentation

friend class EvioCompactReaderV6

friend

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

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation