FST::Data_File_TRN< DATATYPE, IDXTYPE > Class Template Reference

TRN data format filter. More...

#include <data_file_TRN.hpp>

Public Member Functions
void	open (const std::string &filename)
	opens TRN file and reads header
void	close ()
	closes TRN file if it is open
const unsigned int	getNoOfFeatures () const
	data dimensionality, as read from the header's #features line
const unsigned int	getNoOfClasses () const
	number of classes, as read from the header's #classes line
const IDXTYPE	getClassSize (const unsigned int cidx) const
bool	read_val (DATATYPE &target)
	Reads the next value from the data section into target; returns false (without throwing) on EOF/parse failure, or if the header was never successfully read (open() failed or was not called).
DATATYPE	read_val ()
	Reads and returns the next value from the data section; throws fst_error on EOF/parse failure, or if the header was never successfully read.

Protected Member Functions
void	GetFileParams ()
	parses the TRN header (opens _filename, reads #datafile/#title/#features/#classes keywords, leaves the file positioned at the start of the data section in _datastart); throws fst_error on any malformed header

Protected Attributes
std::string	_filename
	input data file name, as passed to open()
std::string	_title
	optional data title (part of the data file); defaults to "no title" if the header omits #title
unsigned int	_no_of_features
	number of features (read from the header)
unsigned int	_no_of_classes
	number of classes (read from the header)
std::vector< IDXTYPE >	_class_sizes
	per-class sample counts, indexed by class index
IDXTYPE	_datastart
	file offset of the start of data past the header
int	_valid
	indicates the state, when header is successfully read and file open and ready to be read for actual data.
FILE *	_file
	the open TRN file handle, or nullptr if none is open

Private Member Functions
	Data_File_TRN (const Data_File_TRN &)
	declared, not defined -> prevents pass-by-value/copy (predates the C++11 =delete idiom used elsewhere in FST4)

Detailed Description

template<typename DATATYPE, typename IDXTYPE>
class FST::Data_File_TRN< DATATYPE, IDXTYPE >

TRN data format filter.

Reads FST's own plain-text data format. A TRN file is a header followed by a data section.

Header. One keyword per line, the keyword being the line's first word:

• #datafile – file-type marker, takes no argument. REQUIRED, and must precede every other keyword.
• #title <text> – optional; the rest of the line is the data set's title. Longer than 499 characters it is truncated. Omitted, the title reads "no title".
• #features <N> – REQUIRED; N is the data dimensionality, at least 1.
• #classes <K> <n1>,<n2>,... – REQUIRED; K is the number of classes, followed by exactly K per-class sample counts. Commas and whitespace separate the counts interchangeably. Every count must be at least 1.
• #data – optional; marks the end of the header. If it is absent, the header ends at the first line that is neither blank, a comment, nor a keyword, and that line is read as the first row of data.

A line whose first non-blank character is a semicolon is a comment, and blank lines are ignored; both may appear anywhere in the header. No keyword may appear twice. Keyword order is otherwise free, except that #datafile comes first.

Data section. Whitespace-separated decimal numbers, read strictly in order: all samples of class 1, then all samples of class 2, and so on; within a class, one sample after another, each sample being #features consecutive values. Line breaks carry no meaning – only the sequence of numbers matters, although one sample per line is the usual layout. There is NO class-label column: class membership is positional and comes entirely from the counts on the #classes line, so the file must hold at least features * (n1+n2+...+nK) values.

A minimal example (2 features, 2 classes of 3 and 2 samples):

#datafile
#title A tiny example
; comments start with a semicolon
#features 2
#classes  2  3,2
#data
0.1 0.4
0.2 0.5
0.3 0.6
1.1 1.4
1.2 1.5

Note

The reader is written around C stdio and fixed-size line buffers: a header line longer than 999 characters is truncated, and the per-class counts are parsed through int, so a class larger than INT_MAX is not representable. Neither limit is reachable with realistic data. Malformed headers throw fst_error; see GetFileParams() for what each error code means.

Member Function Documentation

getClassSize()

template<typename DATATYPE, typename IDXTYPE>

const IDXTYPE FST::Data_File_TRN< DATATYPE, IDXTYPE >::getClassSize ( const unsigned int cidx ) const

inline

size of class cidx, as read from the header's #classes line; 0 if cidx is out of range

GetFileParams()

template<typename DATATYPE, typename IDXTYPE>

void FST::Data_File_TRN< DATATYPE, IDXTYPE >::GetFileParams ( )

protected

parses the TRN header (opens _filename, reads #datafile/#title/#features/#classes keywords, leaves the file positioned at the start of the data section in _datastart); throws fst_error on any malformed header

Every failure throws fst_error with the same message text and a distinguishing code: 1 the file cannot be opened; 5 a keyword occurs twice; 6 a keyword or a data row appears before #datafile and #features have both been seen; 7 the #features argument is not a number; 8 the #classes argument is not a number, or the #classes line is missing altogether; 9 one of the per-class counts is not a number; 10 an unrecognized line appears before the header is complete; 11 the file holds nothing but blank and comment lines; 12 the file ends inside the header (neither a data row nor a #data line follows it); 88 the number of per-class counts differs from the declared class count; 100 fewer than one class; 101 fewer than one feature; 102 a class with fewer than one sample.

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

• /Users/psms/dev/devtest1/_src_dataio/data_file_TRN.hpp