FX::QGZipDevice Class Reference
[File type i/o devices]

#include <QGZipDevice.h>

Inheritance diagram for FX::QGZipDevice:

[legend]

List of all members.

---

Detailed Description

Provides a filter i/o device which transparently translates .gz files.

This is a useful little class which shows the power of the TnFOX i/o class structure. Quite simply, it takes a QIODevice which accesses the .gz file and provides the decompressed version to anything using it. You can use it for reading or writing.

You can especially combine this with QTrans translation files to markedly reduce their size and loading time. Simply attach the i/o device accessing the translation file to an instance of this class using setGZData(). Then read from this instance instead.

Implementation notes:

Since the process of inflation and deflation is slow, the class internally decompresses to a QBuffer on open() and all work is done to and from this buffer. Only on close() or flush() is the data in the buffer gzipped back to the gzdata source.

The source if not already open is opened on open() - if being reopened it does not reset the file pointer so ensure it's at the right place. After open() it leaves the file pointer pointing after the .gz data.

On close() or flush(), the file pointer is first set to zero and after writing a truncate() is issued to the source to remove any extraneous data. If opened as read only or write only, the device behaves correctly and doesn't issue anything incorrect (or at least it shouldn't!). QGZipDevice never closes the source when you close() it.

Note:

You need the zlib library available for this to work. If it's missing an exception is generated if you try to use it.

This class uses the zlib library and hacked together parts of its sample code (C) 1995-1998 Jean-loup Gailly and Mark Adler

Public Types
enum	CRLFType { Default, Unix, MacOS, MSDOS }
enum	UnicodeType {   NoTranslation, UTF8, UTF16, UTF16LE,   UTF32, UTF32LE }
typedef FXfval	Offset
Public Member Functions
	QGZipDevice (QIODevice *gzdata=0)
QIODevice *	GZData () const
void	setGZData (QIODevice *gzdata)
virtual bool	open (FXuint mode)
virtual void	close ()
virtual void	flush ()
virtual FXfval	size () const
virtual void	truncate (FXfval size)
virtual FXfval	at () const
virtual bool	at (FXfval newpos)
virtual bool	atEnd () const
virtual FXuval	readBlock (char *data, FXuval maxlen)
virtual FXuval	writeBlock (const char *data, FXuval maxlen)
virtual FXuval	readBlockFrom (char *data, FXuval maxlen, FXfval pos)
virtual FXuval	writeBlockTo (FXfval pos, const char *data, FXuval maxlen)
virtual int	getch ()
virtual int	putch (int c)
virtual int	ungetch (int c)
FXuint	flags () const
FXuint	mode () const
FXuint	state () const
CRLFType	crlfFormat () const
void	setCRLFFormat (CRLFType type)
UnicodeType	unicodeTranslation () const
void	setUnicodeTranslation (UnicodeType type)
bool	isBuffered () const
bool	isRaw () const
bool	isTranslated () const
bool	isUTF16Translated () const
bool	isUTF32Translated () const
bool	isReadable () const
bool	isWriteable () const
bool	isWritable () const
bool	isReadWrite () const
bool	isClosed () const
bool	isInactive () const
bool	isOpen () const
virtual bool	isSynchronous () const
virtual const FXACL &	permissions () const
virtual void	setPermissions (const FXACL &)
FXuval	readBlock (FXuchar *data, FXuval maxlen)
FXuval	writeBlock (const FXuchar *data, FXuval maxlen)
virtual FXuval	readLine (char *data, FXuval maxlen)
FXuval	readBlockFrom (FXuchar *data, FXuval maxlen, FXfval pos)
FXuval	writeBlockTo (FXfval pos, const FXuchar *data, FXuval maxlen)
FXfval	shredData (FXfval offset, FXfval len=(FXfval)-1)
Static Public Member Functions
static UnicodeType	determineUnicodeType (FXuchar *data, FXuval len) throw ()
static FXuval	applyCRLF (FXuchar *FXRESTRICT output, const FXuchar *FXRESTRICT input, FXuval outputlen, FXuval &inputlen, CRLFType crlftype=Default, UnicodeType utftype=NoTranslation)
static FXuval	removeCRLF (FXuchar *FXRESTRICT output, const FXuchar *FXRESTRICT input, FXuval outputlen, FXuval &inputlen, UnicodeType utftype=NoTranslation)
Protected Member Functions
void	setFlags (int f)
void	setMode (int m)
void	setState (int s)
Protected Attributes
FXfval	ioIndex
Friends
FXAPI FXStream &	operator<< (FXStream &s, QIODevice &i)
FXAPI FXStream &	operator>> (FXStream &s, QIODevice &i)

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Member Enumeration Documentation

enum FX::QIODevice::CRLFType [inherited]

The type of CR/LF encoding you want.

Enumerator:

Default	Uses the host OS format.
Unix	Uses ASCII 10 to delimit lines.
MacOS	Uses ASCII 13 to delimit lines.
MSDOS	Uses ASCII 13,10 to delimit lines.

enum FX::QIODevice::UnicodeType [inherited]

The type of unicode translation you want.

Enumerator:

NoTranslation	Performs no translation.
UTF8	Outputs in native UTF-8.
UTF16	Converts between native (UTF-8) and UTF-16 big endian.
UTF16LE	Converts between native (UTF-8) and UTF-16 little endian.
UTF32	Converts between native (UTF-8) and UTF-32 big endian.
UTF32LE	Converts between native (UTF-8) and UTF-32 little endian.

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Member Function Documentation

QIODevice* FX::QGZipDevice::GZData

(

)

const

Returns the device being used as .gz source.

void FX::QGZipDevice::setGZData

(

QIODevice *

gzdata

)

Sets the device being usied as .gz source.

virtual bool FX::QGZipDevice::open

(

FXuint

mode

)

[virtual]

Opens the device for the specified access.

Implements FX::QIODevice.

virtual void FX::QGZipDevice::close

(

)

[virtual]

Closes the device.

Implements FX::QIODevice.

virtual void FX::QGZipDevice::flush

(

)

[virtual]

Flushes the device's write buffer.

Implements FX::QIODevice.

virtual FXfval FX::QGZipDevice::size

(

)

const [virtual]

Returns the size of the data being accessed by the device.

Implements FX::QIODevice.

virtual void FX::QGZipDevice::truncate

(

FXfval

size

)

[virtual]

Truncates the data to the specified size. Extends the file if necessary & doesn't affect the current file pointer unless it is beyond the new file size, in which case it is moved to the end of the new file

Implements FX::QIODevice.

virtual FXfval FX::QGZipDevice::at

(

)

const [virtual]

Returns the current file pointer within the device

Note:

With IO_Translate enabled, this increments faster than the return values from either readBlock() or writeBlock()

Reimplemented from FX::QIODevice.

virtual bool FX::QGZipDevice::at

(

FXfval

newpos

)

[virtual]

Sets the current file pointer

Note:

With IO_Translate enabled, setting to anything other than a previously read at() can be hazardous.

Reimplemented from FX::QIODevice.

virtual bool FX::QGZipDevice::atEnd

(

)

const [virtual]

Returns true if there is no more data available to be read from the device.

Reimplemented from FX::QIODevice.

virtual FXuval FX::QGZipDevice::readBlock	(	char *	data,
		FXuval	maxlen
	)			[virtual]

Reads up to the specified quantity of bytes into the buffer, returning how much was actually read

Note:

With IO_Translate enabled, this routine regularly returns less read than maxlen (as the CR's are stripped out).

Implements FX::QIODevice.

virtual FXuval FX::QGZipDevice::writeBlock	(	const char *	data,
		FXuval	maxlen
	)			[virtual]

Writes up to the specified quantity of bytes from the buffer, returning how much was actually written. Note that less being written due to error is returned as an exception, but some devices may write less in a non-error situation.

Implements FX::QIODevice.

virtual FXuval FX::QGZipDevice::readBlockFrom	(	char *	data,
		FXuval	maxlen,
		FXfval	pos
	)			[virtual]

Combines an at() and readBlock() together. Can be much more efficient than those two operations individually with some i/o devices, plus it's synchronous and thus threadsafe

Implements FX::QIODevice.

virtual FXuval FX::QGZipDevice::writeBlockTo	(	FXfval	pos,
		const char *	data,
		FXuval	maxlen
	)			[virtual]

Combines an at() and writeBlock() together. Can be much more efficient than those two operations individually with some i/o devices, plus it's synchronous and thus threadsafe

Implements FX::QIODevice.

virtual int FX::QGZipDevice::getch

(

)

[virtual]

Reads a single byte. Returns -1 for no data found.

Reimplemented from FX::QIODevice.

virtual int FX::QGZipDevice::putch

(

int

c

)

[virtual]

Writes a single byte.

Reimplemented from FX::QIODevice.

virtual int FX::QGZipDevice::ungetch

(

int

c

)

[virtual]

Pushes back a byte to the read buffer.

Implements FX::QIODevice.

FXuint FX::QIODevice::flags

(

)

const [inline, inherited]

Returns the flags of this device.

FXuint FX::QIODevice::mode

(

)

const [inline, inherited]

Returns the mode of this device

See also:

QIODeviceOpenFlags

FXuint FX::QIODevice::state

(

)

const [inline, inherited]

Returns the state of this device

See also:

QIODeviceStateFlags

CRLFType FX::QIODevice::crlfFormat

(

)

const [inline, inherited]

Returns the CR/LF format of this device.

void FX::QIODevice::setCRLFFormat

(

CRLFType

type

)

[inline, inherited]

Sets the CR/LF format for output of this device.

UnicodeType FX::QIODevice::unicodeTranslation

(

)

const [inline, inherited]

Returns the unicode translation of this device.

void FX::QIODevice::setUnicodeTranslation

(

UnicodeType

type

)

[inline, inherited]

Sets the unicode translation of this device.

bool FX::QIODevice::isBuffered

(

)

const [inline, inherited]

Returns true if the device is buffered.

bool FX::QIODevice::isRaw

(

)

const [inline, inherited]

Returns true if the device is unbuffered.

bool FX::QIODevice::isTranslated

(

)

const [inline, inherited]

Returns true if the device is LR/CF translated.

bool FX::QIODevice::isUTF16Translated

(

)

const [inline, inherited]

Returns true if the device is UTF-16 translated.

bool FX::QIODevice::isUTF32Translated

(

)

const [inline, inherited]

Returns true if the device is UTF-32 translated.

bool FX::QIODevice::isReadable

(

)

const [inline, inherited]

Returns true if the device is readable.

bool FX::QIODevice::isWriteable

(

)

const [inline, inherited]

Returns true if the device is writeable.

bool FX::QIODevice::isReadWrite

(

)

const [inline, inherited]

Returns true if the device is readable & writeable.

bool FX::QIODevice::isClosed

(

)

const [inline, inherited]

Returns true if the device is closed.

bool FX::QIODevice::isOpen

(

)

const [inline, inherited]

Returns true if the device is opened.

virtual bool FX::QIODevice::isSynchronous

(

)

const [inline, virtual, inherited]

Returns true if this device is a synchronous device.

Reimplemented in FX::QIODeviceS, and FX::QSSLDevice.

virtual const FXACL& FX::QIODevice::permissions

(

)

const [virtual, inherited]

Returns the ACL for this device.

Reimplemented in FX::QBlkSocket, FX::QFile, FX::QMemMap, FX::QPipe, and FX::QSSLDevice.

virtual void FX::QIODevice::setPermissions

(

const FXACL &

)

[virtual, inherited]

Sets the ACL for this device.

Reimplemented in FX::QFile, FX::QMemMap, FX::QPipe, and FX::QSSLDevice.

virtual FXuval FX::QIODevice::readLine	(	char *	data,
		FXuval	maxlen
	)			[virtual, inherited]

Reads data until an end-of-line or maxlen is exceeded.

static UnicodeType FX::QIODevice::determineUnicodeType	(	FXuchar *	data,
		FXuval	len
	)			throw () [static, inherited]

Looks at a sample of data and determines what kind of Unicode text it is, returning UnicodeType::NoTranslation if it isn't text. This routine isn't foolproof, but it's a good guess

static FXuval FX::QIODevice::applyCRLF	(	FXuchar *FXRESTRICT	output,
		const FXuchar *FXRESTRICT	input,
		FXuval	outputlen,
		FXuval &	inputlen,
		CRLFType	crlftype = Default,
		UnicodeType	utftype = NoTranslation
	)			[static, inherited]

Applies CR/LF and optional UTF-x translation returning bytes output. If outputlen would run out before inputlen can be exhausted it will return early (eg; if mid newline, or mid UTF-x sequence). You should rewind processing to the difference between entrant inputlen and returned inputlen.

static FXuval FX::QIODevice::removeCRLF	(	FXuchar *FXRESTRICT	output,
		const FXuchar *FXRESTRICT	input,
		FXuval	outputlen,
		FXuval &	inputlen,
		UnicodeType	utftype = NoTranslation
	)			[static, inherited]

Removes CR/LF translation intelligently (ie; self-adjusts to MS-DOS, Unix and MacOS formats or any mixture of these) and can perform optional UTF-x translation, returning bytes output. If outputlen would run out before inputlen can be exhausted it will return early (eg; if mid newline, or mid UTF-x sequence). You should rewind processing to the difference between entrant inputlen and returned inputlen.

FXfval FX::QIODevice::shredData	(	FXfval	offset,
		FXfval	len = (FXfval)-1
	)			[inherited]

Destroys the len bytes of data from offset offset into the file. Restores the file pointer afterwards and returns how much data was shredded before end of file if encountered. You must have the device open for both reading and writing for this call to succeed.

void FX::QIODevice::setFlags

(

int

f

)

[inline, protected, inherited]

Sets the flags.

void FX::QIODevice::setMode

(

int

m

)

[inline, protected, inherited]

Sets the mode.

void FX::QIODevice::setState

(

int

s

)

[inline, protected, inherited]

Sets the state.

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Friends And Related Function Documentation

FXAPI FXStream& operator<<	(	FXStream &	s,
		QIODevice &	i
	)			[friend, inherited]

Appends the contents of an i/o device to stream s

Warning:

This operation is not thread-safe

FXAPI FXStream& operator>>	(	FXStream &	s,
		QIODevice &	i
	)			[friend, inherited]

Reads all available contents of the stream s to an i/o device, replacing its current contents and resetting the file pointer to the start

Warning:

This operation is not thread-safe

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

• QGZipDevice.h