List of all members
BTranslator Class Referenceabstract

Abstract class that defines the necessary functionality of a translator. More...

Inherits BArchivable.

Public Member Functions

Constructor and reference counting
 BTranslator ()
 Creates a new BTranslator and sets its reference count to 1. More...
 
BTranslatorAcquire ()
 Increments the reference count by 1 and returns a pointer to itself. More...
 
BTranslatorRelease ()
 Decrements the reference count by 1. If the reference count is decreased to zero, the object is deleted. More...
 
int32 ReferenceCount ()
 Gets the current reference count. More...
 
Accessors
virtual const char * TranslatorName () const =0
 Pure virtual. Returns the name of the translator. More...
 
virtual const char * TranslatorInfo () const =0
 Pure virtual. Returns a brief description of the translator. More...
 
virtual int32 TranslatorVersion () const =0
 Pure virtual. Returns the version of the translator. More...
 
virtual const translation_format * InputFormats (int32 *_count) const =0
 Pure virtual. Returns an array containing information about all input formats the translator can handle. More...
 
virtual const translation_format * OutputFormats (int32 *_count) const =0
 Pure virtual. Returns an array containing information about all output formats the translator can produce. More...
 
Core methods
virtual status_t Identify (BPositionIO *source, const translation_format *format, BMessage *extension, translator_info *info, uint32 outType)=0
 Pure virtual. Analyzes source and decides whether this translator can work with the provided format. More...
 
virtual status_t Translate (BPositionIO *source, const translator_info *info, BMessage *extension, uint32 outType, BPositionIO *destination)=0
 Pure virtual. Reads the provided data and tries to translate it to a given format. More...
 
Configuration methods
virtual status_t MakeConfigurationView (BMessage *extension, BView **_view, BRect *_extent)
 Virtual. Creates a BView that contains information and configuration options for the translator. More...
 
virtual status_t GetConfigurationMessage (BMessage *extension)
 Populates a BMessage with the settings of the translator. More...
 
- Public Member Functions inherited from BArchivable
 BArchivable (BMessage *from)
 Constructor. Does important behind-the-scenes work in the unarchiving process. More...
 
 BArchivable ()
 Constructor. Does nothing. More...
 
virtual ~BArchivable ()
 Destructor. Does nothing. More...
 
virtual status_t AllArchived (BMessage *archive) const
 Method relating to the use of BArchiver. More...
 
virtual status_t AllUnarchived (const BMessage *archive)
 Method relating to the use of BUnarchiver. More...
 
virtual status_t Archive (BMessage *into, bool deep=true) const
 Archive the object into a BMessage. More...
 
virtual status_t Perform (perform_code d, void *arg)
 Perform some action (Internal method defined for binary compatibility purposes).
 

Additional Inherited Members

- Static Public Member Functions inherited from BArchivable
static BArchivableInstantiate (BMessage *archive)
 Static member to restore objects from messages. More...
 

Detailed Description

Abstract class that defines the necessary functionality of a translator.

BTranslator is the core class of the translation kit. Every translator defines input and output data types it can work with. A BTranslator uses BPositionIO as an abstraction for the data it operates on. It is able to decide wether incoming data is of any of its known input types and, upon successful identification, translate it to any of its output formats. It may also provide a config view that appears in the DataTranslations preference app.

Usually, a translator is very specific. It only offers translations between the format it was created for and the basic format for that media type. As an example, the translator for GIF images only translates between GIF images and bitmaps, the baseline format for images.

The function make_nth_translator enables add-ons to expose translators. Communication between applications and BTranslators is carried out by the BTranslatorRoster class.

Note
Another option to create a translator is using a BFuncTranslator.
Remarks
In most cases it is easier to derive from BaseTranslator instead of BTranslator. BaseTranslator provides a lot of functionality that is common for most translators as well as a unified method to save settings and routines for handling bitmaps.
Since
BeOS R3

Constructor & Destructor Documentation

◆ BTranslator()

BTranslator::BTranslator ( )

Creates a new BTranslator and sets its reference count to 1.

Since
BeOS R3

Member Function Documentation

◆ Acquire()

BTranslator * BTranslator::Acquire ( )

Increments the reference count by 1 and returns a pointer to itself.

Returns
this.
Since
BeOS R3

◆ GetConfigurationMessage()

status_t BTranslator::GetConfigurationMessage ( BMessage extension)
virtual

Populates a BMessage with the settings of the translator.

A standard set of possible fields is defined in TranslatorFormats.h. This method is optional. If the translator chose not to implement it, B_ERROR will be returned.

Parameters
extensionThe BMessage that is populated.
Return values
B_OKEverything went well.
B_ERRORAn error occurred or the method was not overriden by the translator.
B_BAD_VALUEextension was NULL.
Since
BeOS R3

◆ Identify()

status_t BTranslator::Identify ( BPositionIO source,
const translation_format *  format,
BMessage extension,
translator_info *  info,
uint32  outType 
)
pure virtual

Pure virtual. Analyzes source and decides whether this translator can work with the provided format.

The translator examines the data in source and tries to identify its format (for instance by checking for magic numbers). It may use the hints provided by format. If it is successful, and it is able to translate the data at hand to outType, it populates info with information about the input format and returns B_OK. If it is unable to identify the data or cannot translate it to outType, it returns B_NO_TRANSLATOR.

Parameters
sourceRead and seek interface to the input data.
formatHints about the incoming data.
extensionA message containing configuration information for the translator. A standard set of possible fields is defined in TranslatorFormats.h.
infoWhere the translator will write information about the determined input format in case identification is successful.
outTypeIf outType is non-zero, identification will only be successful if the translator can transform the data in source to the format denoted by outType.
Warning
When creating a translator, be prepared for the information in format to be inaccurate or wrong.
Return values
B_OKThe translator has identified the data in source, has verified its ability to translate it to outType and has written information describing it to info.
B_NO_TRANSLATORThe translator does not know how to handle the data in source or cannot translate it to outType.
B_BAD_VALUEextension was NULL or contained bad data.
B_ERRORAn error occurred.
Since
BeOS R3

◆ InputFormats()

const translation_format * BTranslator::InputFormats ( int32 *  _count) const
pure virtual

Pure virtual. Returns an array containing information about all input formats the translator can handle.

Parameters
_countWhere the number of input formats that are returned will be written.
Returns
A pointer to the first element of the array of input formats.
Since
BeOS R3

◆ MakeConfigurationView()

status_t BTranslator::MakeConfigurationView ( BMessage extension,
BView **  _view,
BRect _extent 
)
virtual

Virtual. Creates a BView that contains information and configuration options for the translator.

This method is optional. If the translator chose not to implement it, B_ERROR will be returned.

Parameters
extensionA message containing configuration information for the translator. A standard set of possible fields is defined in TranslatorFormats.h.
_viewWhere a pointer to the newly created configuration view will be stored.
_extentWhere the size of the newly created configuration view will be stored.
Return values
B_OKEverything went well.
B_ERRORAn error occurred or the method was not overriden by the translator.
B_BAD_VALUE_view or _extent were NULL or extension was NULL or contained bad data.
Since
BeOS R3

◆ OutputFormats()

const translation_format * BTranslator::OutputFormats ( int32 *  _count) const
pure virtual

Pure virtual. Returns an array containing information about all output formats the translator can produce.

Parameters
_countWhere the number of output formats that are returned will be written.
Returns
A pointer to the first element of the array of output formats.
Since
BeOS R3

◆ ReferenceCount()

int32 BTranslator::ReferenceCount ( )

Gets the current reference count.

Returns
The current reference count.
Since
BeOS R3

◆ Release()

BTranslator * BTranslator::Release ( )

Decrements the reference count by 1. If the reference count is decreased to zero, the object is deleted.

Returns
this if the object was not destroyed, NULL if it was.
Since
BeOS R3

◆ Translate()

status_t BTranslator::Translate ( BPositionIO source,
const translator_info *  info,
BMessage extension,
uint32  outType,
BPositionIO destination 
)
pure virtual

Pure virtual. Reads the provided data and tries to translate it to a given format.

The translator attempts to translate the data in source, which may or may not have the format represented by info, to outType and then write the result to destination. Upon success, it returns B_OK.

Parameters
sourceRead and seek interface to the input data.
infoHints about the incoming data.
extensionA message containing configuration information for the translator. A standard set of possible fields is defined in TranslatorFormats.h.
outTypeThe identifier of the desired output format. An outType of 0 is equivalent to the defualt format for the media type if the translator.
destinationWrite interface for the destination of the data.
Warning
When creating a translator, be prepared for the information in format to be inaccurate or wrong.
Return values
B_OKThe translated data was successfully written to destination.
B_ERRORAn error occurred during memory allocation or the conversion itself.
B_BAD_VALUEextension was NULL or contained bad data.
B_NO_TRANSLATORThe translator cannot handle the input.
Since
BeOS R3

◆ TranslatorInfo()

const char * BTranslator::TranslatorInfo ( ) const
pure virtual

Pure virtual. Returns a brief description of the translator.

Returns
A brief description of the translator.
Since
BeOS R3

◆ TranslatorName()

const char * BTranslator::TranslatorName ( ) const
pure virtual

Pure virtual. Returns the name of the translator.

Amongst other uses, the name is used to populate Save as-dropdowns and for the preference window.

Returns
The name of the translator.
Since
BeOS R3

◆ TranslatorVersion()

int32 BTranslator::TranslatorVersion ( ) const
pure virtual

Pure virtual. Returns the version of the translator.

The correct way to format the version is using the B_TRANSLATION_MAKE_VERSION macro from TranslationDefs.h.

Returns
The version of the translator.
Since
BeOS R3