BinFileHelper Class Reference

#include <binfilehelper.h>

Public Types
enum	Errors {   ERR_NULL , ERR_FILEOPEN , ERR_FD_TRUNC , ERR_INDEX_TRUNC ,   ERR_INDEX_BADID , ERR_INDEX_IDMISMATCH , ERR_INDEX_BADOFFSET , ERR_BADSEEK }

Public Member Functions
	BinFileHelper ()
	~BinFileHelper ()
void	closeFile ()
bool	getByteSwap () const
long	getDataOffset () const
QString	getError ()
int	getErrorNumber ()
struct dataElement	getField (const QString &fieldName) const
int	getFieldCount () const
FILE *	getFileHandle () const
QString	getHeaderText () const
long	getIndexTableOffset () const
long	getOffset (int id) const
unsigned long	getRecordCount () const
unsigned int	getRecordCount (int id) const
int	guessRecordSize () const
bool	isField (const QString &FieldName) const
FILE *	openFile (const QString &fileName)
bool	propertiesUpdated () const
bool	readHeader ()
void	setRecordSize (int rs)

Static Public Member Functions
static bool	testFileExists (const QString &fileName)
static int	unsigned_KDE_fseek (FILE *stream, quint32 offset, int whence)

Detailed Description

This class provides utility functions to handle binary data files in the format prescribed by KStars.

The file format is designed specifically to support data that has the form of an array of structures. See data/README.fileformat for details. The methods use primitive C file I/O routines defined in stdio.h to obtain efficiency

Implements an interface to handle binary data files used by KStars

Author

Akarsh Simha

Version

1.0

Definition at line 38 of file binfilehelper.h.

Member Enumeration Documentation

Errors

enum BinFileHelper::Errors

An enum providing user-friendly names for errors encountered.

Enumerator
ERR_NULL	No error occurred
ERR_FILEOPEN	File could not be opened
ERR_FD_TRUNC	Field descriptor table is truncated
ERR_INDEX_TRUNC	File ends prematurely, before expected end of index table
ERR_INDEX_BADID	Index table has an invalid ID entry
ERR_INDEX_IDMISMATCH	Index table has a mismatched ID entry [ID found in the wrong place]
ERR_INDEX_BADOFFSET	Offset / Record count specified in the Index table is bad
ERR_BADSEEK	Premature end of file / bad seek while reading index table

Definition at line 201 of file binfilehelper.h.

Constructor & Destructor Documentation

BinFileHelper()

BinFileHelper::BinFileHelper

(

)

Constructor.

Definition at line 16 of file binfilehelper.cpp.

~BinFileHelper()

BinFileHelper::~BinFileHelper

(

)

Destructor.

Definition at line 21 of file binfilehelper.cpp.

Member Function Documentation

closeFile()

void BinFileHelper::closeFile

(

)

Close the binary data file.

Definition at line 276 of file binfilehelper.cpp.

getByteSwap()

bool BinFileHelper::getByteSwap ( ) const

inline

Should we do byte swapping?

Note

To be called only after the header has been parsed

Returns

true if we must do byte swapping, false if not

Definition at line 136 of file binfilehelper.h.

getDataOffset()

long BinFileHelper::getDataOffset ( ) const

inline

Returns the offset at which the data begins.

Returns

The value of dataOffset if indexUpdated, else zero

Definition at line 175 of file binfilehelper.h.

getError()

QString BinFileHelper::getError

(

)

Get error string.

Returns

A QString containing the error message to be displayed

Definition at line 289 of file binfilehelper.cpp.

getErrorNumber()

int BinFileHelper::getErrorNumber

(

)

Get error number.

Returns

A number corresponding to the error

Definition at line 282 of file binfilehelper.cpp.

getField()

struct dataElement BinFileHelper::getField

(

const QString &

fieldName

)

const

Get field by name.

Parameters

fieldName

Name of the field

Returns

A dataElement structure containing field data if the field exists, containing junk values if the field doesn't exist

Definition at line 296 of file binfilehelper.cpp.

getFieldCount()

int BinFileHelper::getFieldCount ( ) const

inline

Returns the number of fields as suggested by the field descriptor in the header.

Returns

Number of fields, or zero if the FD hasn't been read yet

Definition at line 163 of file binfilehelper.h.

getFileHandle()

FILE * BinFileHelper::getFileHandle ( ) const

inline

Get the file handle corresponding to the currently open file.

Returns

The filehandle if a file is open, nullptr if no file is open

Definition at line 109 of file binfilehelper.h.

getHeaderText()

QString BinFileHelper::getHeaderText ( ) const

inline

Returns the header text.

Returns

QString containing the header text if header has been read, blank QString otherwise

Definition at line 169 of file binfilehelper.h.

getIndexTableOffset()

long BinFileHelper::getIndexTableOffset ( ) const

inline

Returns the offset at which the index table begins.

Returns

The value of itableOffset if FDUpdated, else zero

Definition at line 181 of file binfilehelper.h.

getOffset()

long BinFileHelper::getOffset ( int id ) const

inline

Returns the offset in the file corresponding to the given index ID.

Parameters

id	ID of the index entry whose offset is required

Returns

The offset corresponding to that index ID, 0 if the index hasn't been read

Definition at line 116 of file binfilehelper.h.

getRecordCount() [1/2]

unsigned long BinFileHelper::getRecordCount ( ) const

inline

Returns the total number of records in the file.

Returns

The number of records in the file, or 0 if the index has not been read

Definition at line 129 of file binfilehelper.h.

getRecordCount() [2/2]

unsigned int BinFileHelper::getRecordCount ( int id ) const

inline

Returns the number of records under the given index ID.

Parameters

id	ID of the index entry

Returns

The number of records under index that index ID, or 0 if the index has not been read

Definition at line 123 of file binfilehelper.h.

guessRecordSize()

int BinFileHelper::guessRecordSize ( ) const

inline

Return a guessed record size.

Note

The record size returned is guessed from the field descriptor table and may not be correct in many cases

Returns

A guessed size of the record, or zero if the FD hasn't been read yet

Definition at line 144 of file binfilehelper.h.

isField()

bool BinFileHelper::isField

(

const QString &

FieldName

)

const

Check whether a field exists.

Parameters

FieldName

Name of the field

Returns

True if the field exists, false if it does not or the FD hasn't been read yet

Definition at line 311 of file binfilehelper.cpp.

openFile()

FILE * BinFileHelper::openFile

(

const QString &

fileName

)

WARNING: This function may not be compatible in other locales, because it calls QString::toAscii.

Open a Binary data file and set the handle

Parameters

fileName

Reference to QString containing the name of the file

Returns

Handle to the file if successful, nullptr if an error occurred, sets the error.

Definition at line 72 of file binfilehelper.cpp.

propertiesUpdated()

bool BinFileHelper::propertiesUpdated ( ) const

inline

Check whether file properties are real or bogus.

Returns

The value of private variable indexUpdated, which is true if data has been updated

Definition at line 103 of file binfilehelper.h.

readHeader()

bool BinFileHelper::readHeader

(

)

Read the header and index table from the file and fill up the QVector s with the entries.

Returns

True if successful, false if an error occurred, sets the error.

Definition at line 250 of file binfilehelper.cpp.

setRecordSize()

void BinFileHelper::setRecordSize ( int rs )

inline

Override record size.

Note

To be used to override the guess in case the guess is wrong. This method should be called before calling readHeader(). Use this only if you are sure of the recordSize or are sure that the guess will not work.

Parameters

rs	The correct recordSize

Definition at line 153 of file binfilehelper.h.

testFileExists()

bool BinFileHelper::testFileExists ( const QString & fileName )

static

Checks if a file exists.

WARNING: Might be incompatible in other locales

Definition at line 57 of file binfilehelper.cpp.

unsigned_KDE_fseek()

int BinFileHelper::unsigned_KDE_fseek ( FILE * stream, quint32 offset, int whence )

static

Wrapper around fseek for large offsets.

fseek takes a signed long for the offset, since it can be either positive or negative. If the argument is a 32-bit unsigned integer, fseek will fail in most situations, since that will be interpreted as a number of the opposite sign. This wrapper circumvents that problem by repeatedly calling fseek twice if the offset is too large. Useful when 64-bit handling is really not necessary.

Returns

Zero on success. Else, error code of the first failing fseek call.

Note

Clearly, this method can move forward only. When we need one that goes back, we'll implement that.

Definition at line 321 of file binfilehelper.cpp.

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

• binfilehelper.h
• binfilehelper.cpp