A class for managing and converting between different DICOM character sets. More...

Public Member Functions
	DcmSpecificCharacterSet ()
	constructor.
virtual	~DcmSpecificCharacterSet ()
	destructor
virtual void	clear ()
	clear the internal state.
virtual	operator OFBool () const
	query whether selectCharacterSet() has successfully been called for this object, i.e. whether convertString() may be called.
virtual OFBool	operator! () const
	query whether selectCharacterSet() has not been called before, i.e. convertString() would fail.
virtual const OFString &	getSourceCharacterSet () const
	get currently selected source DICOM character set(s).
virtual const OFString &	getDestinationCharacterSet () const
	get currently selected destination DICOM character set.
virtual const OFString &	getDestinationEncoding () const
	get currently selected destination encoding, i.e. the name of the character set as used by the underlying character encoding library for the conversion.
virtual unsigned	getConversionFlags () const
	get flags controlling converter behavior, e.g. specifying how illegal character sequences should be handled during conversion.
virtual OFCondition	setConversionFlags (const unsigned flags)
	set flags controlling converter behavior, e.g. illegal character sequences should be handled during conversion.
virtual OFCondition	selectCharacterSet (const OFString &fromCharset, const OFString &toCharset="ISO_IR 192")
	select DICOM character sets for the input and output string, between which subsequent calls of convertString() convert.
virtual OFCondition	selectCharacterSet (DcmItem &dataset, const OFString &toCharset="ISO_IR 192")
	select DICOM character sets for the input and output string, between which subsequent calls of convertString() convert.
virtual OFCondition	convertString (const OFString &fromString, OFString &toString, const OFString &delimiters="")
	convert the given string from the selected source character set(s) to the selected destination character set.
virtual OFCondition	convertString (const char *fromString, const size_t fromLength, OFString &toString, const OFString &delimiters="")
	convert the given string from the selected source character set(s) to the selected destination character set.

Static Public Member Functions
static OFBool	isConversionAvailable ()
	check whether the underlying character set conversion library is available.
static size_t	countCharactersInUTF8String (const OFString &utf8String)
	count characters in given UTF-8 string and return the resulting number of so-called "code points".

Protected Member Functions
virtual OFCondition	determineDestinationEncoding (const OFString &toCharset)
	determine the destination character encoding (as used by the underlying character encoding library) from the given DICOM defined term (specific character set), and set the member variables accordingly.
virtual OFCondition	selectCharacterSetWithoutCodeExtensions ()
	select a particular DICOM character set without code extensions for subsequent conversions.
virtual OFCondition	selectCharacterSetWithCodeExtensions (const unsigned long sourceVM)
	select a particular DICOM character set with code extensions for subsequent conversions.
virtual OFCondition	convertStringWithoutCodeExtensions (const char *fromString, const size_t fromLength, OFString &toString, const OFString &delimiters)
	convert the given string from the selected source character set (without code extensions) to the selected destination character set
virtual OFCondition	convertStringWithCodeExtensions (const char *fromString, const size_t fromLength, OFString &toString, const OFString &delimiters, const OFBool hasEscapeChar)
	convert the given string from the selected source character set(s) to the selected destination character set.
virtual OFBool	checkForEscapeCharacter (const char *strValue, const size_t strLength) const
	check whether the given string contains at least one escape character (ESC), because it is used for code extension techniques like ISO 2022
virtual OFString	convertToLengthLimitedOctalString (const char *strValue, const size_t strLength) const
	convert given string to octal format, i.e. all non-ASCII and control characters are converted to their octal representation.

Private Types
typedef OFMap< OFString, OFCharacterEncoding >	T_EncodingConvertersMap
	type definition of a map storing the identifier (key) of a character set and the associated character set converter

Private Attributes
OFString	SourceCharacterSet
	selected source character set(s) based on one or more DICOM defined terms
OFString	DestinationCharacterSet
	selected destination character set based on a single DICOM defined term
OFString	DestinationEncoding
	selected destination encoding based on names supported by the underlying character encoding library
OFCharacterEncoding	DefaultEncodingConverter
	character encoding converter
T_EncodingConvertersMap	EncodingConverters
	map of character set conversion descriptors (only used if multiple character sets are needed)

Detailed Description

A class for managing and converting between different DICOM character sets.

The conversion relies on the OFCharacterEncoding class, which again relies on an underlying character encoding library (e.g. oficonv or libiconv).

Note: Please note that a current limitation is that only a single value is allowed for the destination character set (i.e. no code extensions). Of course, for the source character set, also multiple values are supported.

Constructor & Destructor Documentation

◆ DcmSpecificCharacterSet()

DcmSpecificCharacterSet::DcmSpecificCharacterSet ( )

constructor.

Initializes the member variables.

Member Function Documentation

◆ checkForEscapeCharacter()

virtual OFBool DcmSpecificCharacterSet::checkForEscapeCharacter	(	const char *	strValue,
		const size_t	strLength ) const

protectedvirtual

check whether the given string contains at least one escape character (ESC), because it is used for code extension techniques like ISO 2022

Parameters

strValue	input string to be checked for any escape character
strLength	length of the input string

Returns: OFTrue if an escape character has been found, OFFalse otherwise

◆ clear()

virtual void DcmSpecificCharacterSet::clear ( )

virtual

clear the internal state.

This also forgets about the currently selected character sets, so selectCharacterSet() has to be called again before a string can be converted with convertString().

◆ convertString() [1/2]

virtual OFCondition DcmSpecificCharacterSet::convertString	(	const char *	fromString,
		const size_t	fromLength,
		OFString &	toString,
		const OFString &	delimiters = "" )

virtual

convert the given string from the selected source character set(s) to the selected destination character set.

That means selectCharacterSet() has to be called prior to this method. Since the length of the input string has to be specified explicitly, the string can contain more than one NULL byte.

Note: The conversion code does not perform a thorough validation of the string. For example, characters that are permitted in the source character set but forbidden in DICOM (such as byte positions 0x80-0x9F in ISO_IR 100) may be converted without warning or error.

Parameters

fromString	input string to be converted (using the currently selected character set)
fromLength	length of the input string (number of bytes without the trailing NULL byte)
toString	reference to variable where the converted string (using the currently selected destination character set) is stored
delimiters	optional string of characters that are regarded as delimiters, i.e. when found the character set is switched back to the default. CR, LF, FF and HT are always regarded as delimiters (see DICOM PS 3.5).

Returns: status, EC_Normal if successful, an error code otherwise

◆ convertString() [2/2]

virtual OFCondition DcmSpecificCharacterSet::convertString	(	const OFString &	fromString,
		OFString &	toString,
		const OFString &	delimiters = "" )

virtual

convert the given string from the selected source character set(s) to the selected destination character set.

That means selectCharacterSet() has to be called prior to this method.

Note: The conversion code does not perform a thorough validation of the string. For example, characters that are permitted in the source character set but forbidden in DICOM (such as byte positions 0x80-0x9F in ISO_IR 100) may be converted without warning or error.

Parameters

fromString	input string to be converted (using the currently selected source character set)
toString	reference to variable where the converted string (using the currently selected destination character set) is stored
delimiters	optional string of characters that are regarded as delimiters, i.e. when found the character set is switched back to the default. CR, LF, FF and HT are always regarded as delimiters (see DICOM PS 3.5).

Returns: status, EC_Normal if successful, an error code otherwise

◆ convertStringWithCodeExtensions()

virtual OFCondition DcmSpecificCharacterSet::convertStringWithCodeExtensions	(	const char *	fromString,
		const size_t	fromLength,
		OFString &	toString,
		const OFString &	delimiters,
		const OFBool	hasEscapeChar )

protectedvirtual

convert the given string from the selected source character set(s) to the selected destination character set.

This method supports code extension techniques according to ISO 2022 for the input string.

Parameters

fromString	input string to be converted
fromLength	length of the input string (in bytes)
toString	reference to variable where to store the converted string
delimiters	string of characters regarded as delimiters
hasEscapeChar	flag indicating wether the input string contains one or more escape characters (ESC)

Returns: status, EC_Normal if successful, an error code otherwise

◆ convertStringWithoutCodeExtensions()

virtual OFCondition DcmSpecificCharacterSet::convertStringWithoutCodeExtensions	(	const char *	fromString,
		const size_t	fromLength,
		OFString &	toString,
		const OFString &	delimiters )

protectedvirtual

convert the given string from the selected source character set (without code extensions) to the selected destination character set

Parameters

fromString	input string to be converted
fromLength	length of the input string (in bytes)
toString	reference to variable where to store the converted string
delimiters	string of characters regarded as delimiters

Returns: status, EC_Normal if successful, an error code otherwise

◆ convertToLengthLimitedOctalString()

virtual OFString DcmSpecificCharacterSet::convertToLengthLimitedOctalString	(	const char *	strValue,
		const size_t	strLength ) const

protectedvirtual

convert given string to octal format, i.e. all non-ASCII and control characters are converted to their octal representation.

The total length of the string is always limited to a particular maximum (see implementation). If the converted string would be longer, it is cropped and "..." is appended to indicate this cropping.

Parameters

strValue	input string to be converted and possibly cropped
strLength	length of the input string

Returns: resulting string in octal format

◆ countCharactersInUTF8String()

size_t DcmSpecificCharacterSet::countCharactersInUTF8String ( const OFString & utf8String )

static

count characters in given UTF-8 string and return the resulting number of so-called "code points".

Please note that invalid UTF-8 encodings are not handled properly. ASCII strings (7-bit) are also supported, although OFString::length() is probably much faster.

Parameters

utf8String valid character string with UTF-8 encoding

Returns: number of characters (code points) in given UTF-8 string

◆ determineDestinationEncoding()

virtual OFCondition DcmSpecificCharacterSet::determineDestinationEncoding ( const OFString & toCharset )

protectedvirtual

determine the destination character encoding (as used by the underlying character encoding library) from the given DICOM defined term (specific character set), and set the member variables accordingly.

Parameters

toCharset name of the destination character set used for the output string

Returns: status, EC_Normal if successful, an error code otherwise

◆ getConversionFlags()

virtual unsigned DcmSpecificCharacterSet::getConversionFlags ( ) const

virtual

get flags controlling converter behavior, e.g. specifying how illegal character sequences should be handled during conversion.

Note: This method will always return 0 if no encoder was selected using selectEncoding() before calling it.

Returns: a combination the IllegalSequenceMode constants (bitwise or) that is currently set or 0 if the current mode cannot be determined.

◆ getDestinationCharacterSet()

virtual const OFString & DcmSpecificCharacterSet::getDestinationCharacterSet ( ) const

virtual

get currently selected destination DICOM character set.

Please note that the returned string, which contains a defined term, is always normalized, i.e. leading and trailing spaces have been removed.

Returns: currently selected destination DICOM character set or an empty string if none is selected (identical to ASCII, which is the default)

◆ getDestinationEncoding()

virtual const OFString & DcmSpecificCharacterSet::getDestinationEncoding ( ) const

virtual

get currently selected destination encoding, i.e. the name of the character set as used by the underlying character encoding library for the conversion.

If code extension techniques are used to switch between different character encodings, the main/default encoding is returned.

Returns: currently selected destination encoding or an empty string if none is selected

◆ getSourceCharacterSet()

virtual const OFString & DcmSpecificCharacterSet::getSourceCharacterSet ( ) const

virtual

get currently selected source DICOM character set(s).

Please note that the returned string can contain multiple values (defined terms separated by a backslash) if code extension techniques are used. Furthermore, the returned string is always normalized, i.e. leading and trailing spaces have been removed.

Returns: currently selected source DICOM character set(s) or an empty string if none is selected (identical to ASCII, which is the default)

◆ isConversionAvailable()

OFBool DcmSpecificCharacterSet::isConversionAvailable ( )

static

check whether the underlying character set conversion library is available.

If not, no conversion between different character sets will be possible.

Returns: OFTrue if the character set conversion is available, OFFalse otherwise

◆ operator OFBool()

virtual DcmSpecificCharacterSet::operator OFBool ( ) const

virtual

query whether selectCharacterSet() has successfully been called for this object, i.e. whether convertString() may be called.

Returns: OFTrue if selectCharacterSet() was successfully called before, OFFalse if not (or clear() has been called in the meantime).

◆ operator!()

virtual OFBool DcmSpecificCharacterSet::operator! ( ) const

virtual

query whether selectCharacterSet() has not been called before, i.e. convertString() would fail.

Returns: OFTrue if selectCharacterSet() must be called before using convertString(), OFFalse if it has already been called.

◆ selectCharacterSet() [1/2]

virtual OFCondition DcmSpecificCharacterSet::selectCharacterSet	(	const OFString &	fromCharset,
		const OFString &	toCharset = "ISO_IR 192" )

virtual

select DICOM character sets for the input and output string, between which subsequent calls of convertString() convert.

The defined terms for a particular character set can be found in the DICOM standard, e.g. "ISO_IR 100" for ISO 8859-1 (Latin 1) or "ISO_IR 192" for Unicode in UTF-8. An empty string denotes the default character repertoire, which is ASCII (7-bit). If multiple values are given for 'fromCharset' (separated by a backslash) code extension techniques are used and escape sequences may be encountered in the source string to switch between the specified character sets.

Parameters

fromCharset	name of the source character set(s) used for the input string as given in the DICOM attribute Specific Character Set (0008,0005). Leading and trailing spaces are removed automatically (if present).
toCharset	name of the destination character set used for the output string. Only a single value is permitted (no code extensions). Leading and trailing spaces are removed automatically (if present). The default value is "ISO_IR 192" (Unicode in UTF-8).

Returns: status, EC_Normal if successful, an error code otherwise

◆ selectCharacterSet() [2/2]

virtual OFCondition DcmSpecificCharacterSet::selectCharacterSet	(	DcmItem &	dataset,
		const OFString &	toCharset = "ISO_IR 192" )

virtual

select DICOM character sets for the input and output string, between which subsequent calls of convertString() convert.

The source character set is determined from the DICOM element Specific Character Set (0008,0005) stored in the given dataset/item. The defined terms for the destination character set can be found in the DICOM standard, e.g. "ISO_IR 100" for ISO 8859-1 (Latin 1) or "ISO_IR 192" for Unicode in UTF-8. An empty string denotes the default character repertoire, which is ASCII (7-bit). If multiple values are found in the Specific Character Set element of the given 'dataset' (separated by a backslash) code extension techniques are used and escape sequences may be encountered in the source string to switch between the specified character sets.

Parameters

dataset	DICOM dataset or item from which the source character set should be retrieved. If the data element Specific Character Set (0008,0005) is empty or missing, the default character set (i.e. ASCII) is used.
toCharset	name of the destination character set used for the the output string. Only a single value is permitted (no code extensions). Leading and trailing spaces are removed automatically (if present). The default value is "ISO_IR 192" (Unicode in UTF-8).

Returns: status, EC_Normal if successful, an error code otherwise

◆ selectCharacterSetWithCodeExtensions()

virtual OFCondition DcmSpecificCharacterSet::selectCharacterSetWithCodeExtensions ( const unsigned long sourceVM )

protectedvirtual

select a particular DICOM character set with code extensions for subsequent conversions.

The corresponding DICOM defined terms for the source character set are determined from the member variable 'SourceCharacterSet'.

Parameters

sourceVM value multiplicity of the member variable 'SourceCharacterSet'. Usually, this value has already been determined by the calling method.

Returns: status, EC_Normal if successful, an error code otherwise

◆ selectCharacterSetWithoutCodeExtensions()

virtual OFCondition DcmSpecificCharacterSet::selectCharacterSetWithoutCodeExtensions ( )

protectedvirtual

select a particular DICOM character set without code extensions for subsequent conversions.

The corresponding DICOM defined term for the source character set is determined from the member variable 'SourceCharacterSet'.

Returns: status, EC_Normal if successful, an error code otherwise

◆ setConversionFlags()

virtual OFCondition DcmSpecificCharacterSet::setConversionFlags ( const unsigned flags )

virtual

set flags controlling converter behavior, e.g. illegal character sequences should be handled during conversion.

Precondition: An encoding has been selected by successfully calling OFCharacterEncoding::selectEncoding(), i.e. OFCharacterEncoding::isLibraryAvailable() and *this evaluate to OFTrue.

Parameters

flags the conversion flags that shall be used, a combination of the OFCharacterEncoding::ConversionFlags constants, e.g. TransliterateIllegalSequences | DiscardIllegalSequences.

Returns: EC_Normal if the flags were set, an error code otherwise, i.e. if the flags are not supported by the underlying implementation.

See also: OFCharacterEncoding::supportsConversionFlags()

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

dcmdata/include/dcmtk/dcmdata/dcspchrs.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Types

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ DcmSpecificCharacterSet()

Member Function Documentation

◆ checkForEscapeCharacter()

◆ clear()

◆ convertString() [1/2]

◆ convertString() [2/2]

◆ convertStringWithCodeExtensions()

◆ convertStringWithoutCodeExtensions()

◆ convertToLengthLimitedOctalString()

◆ countCharactersInUTF8String()

◆ determineDestinationEncoding()

◆ getConversionFlags()

◆ getDestinationCharacterSet()

◆ getDestinationEncoding()

◆ getSourceCharacterSet()

◆ isConversionAvailable()

◆ operator OFBool()

◆ operator!()

◆ selectCharacterSet() [1/2]

◆ selectCharacterSet() [2/2]

◆ selectCharacterSetWithCodeExtensions()

◆ selectCharacterSetWithoutCodeExtensions()

◆ setConversionFlags()