C API: UCollationElements. More...

#include "unicode/utypes.h"
#include "unicode/ucol.h"

Macros
#define	UCOL_NULLORDER ((int32_t)0xFFFFFFFF)
	This indicates an error has occurred during processing or if no more CEs is to be returned. More...

Typedefs
typedef struct UCollationElements	UCollationElements
	The UCollationElements struct. More...

Functions
U_CAPI UCollationElements *	ucol_openElements (const UCollator coll, const UChar text, int32_t textLength, UErrorCode *status)
	Open the collation elements for a string. More...

U_CAPI int32_t	ucol_keyHashCode (const uint8_t *key, int32_t length)
	get a hash code for a key... Not very useful! More...

U_CAPI void	ucol_closeElements (UCollationElements *elems)
	Close a UCollationElements. More...

U_CAPI void	ucol_reset (UCollationElements *elems)
	Reset the collation elements to their initial state. More...

U_CAPI int32_t	ucol_next (UCollationElements elems, UErrorCode status)
	Get the ordering priority of the next collation element in the text. More...

U_CAPI int32_t	ucol_previous (UCollationElements elems, UErrorCode status)
	Get the ordering priority of the previous collation element in the text. More...

U_CAPI int32_t	ucol_getMaxExpansion (const UCollationElements *elems, int32_t order)
	Get the maximum length of any expansion sequences that end with the specified comparison order. More...

U_CAPI void	ucol_setText (UCollationElements elems, const UChar text, int32_t textLength, UErrorCode *status)
	Set the text containing the collation elements. More...

U_CAPI int32_t	ucol_getOffset (const UCollationElements *elems)
	Get the offset of the current source character. More...

U_CAPI void	ucol_setOffset (UCollationElements elems, int32_t offset, UErrorCode status)
	Set the offset of the current source character. More...

U_CAPI int32_t	ucol_primaryOrder (int32_t order)
	Get the primary order of a collation order. More...

U_CAPI int32_t	ucol_secondaryOrder (int32_t order)
	Get the secondary order of a collation order. More...

U_CAPI int32_t	ucol_tertiaryOrder (int32_t order)
	Get the tertiary order of a collation order. More...

Detailed Description

C API: UCollationElements.

The UCollationElements API is used as an iterator to walk through each character of an international string. Use the iterator to return the ordering priority of the positioned character. The ordering priority of a character, which we refer to as a key, defines how a character is collated in the given collation object. For example, consider the following in Slovak and in traditional Spanish collation:

.       "ca" -> the first key is key('c') and second key is key('a').
.       "cha" -> the first key is key('ch') and second key is key('a').

And in German phonebook collation,

.       "<ae ligature>b"-> the first key is key('a'), the second key is key('e'), and
.       the third key is key('b').

Example of the iterator usage: (without error checking)

.  void CollationElementIterator_Example()
.  {
.      UChar *s;
.      t_int32 order, primaryOrder;
.      UCollationElements *c;
.      UCollatorOld *coll;
.      UErrorCode success = U_ZERO_ERROR;
.      str=(UChar*)malloc(sizeof(UChar) * (strlen("This is a test")+1) );
.      u_uastrcpy(str, "This is a test");
.      coll = ucol_open(NULL, &success);
.      c = ucol_openElements(coll, str, u_strlen(str), &status);
.      order = ucol_next(c, &success);
.      ucol_reset(c);
.      order = ucol_prev(c, &success);
.      free(str);
.      ucol_close(coll);
.      ucol_closeElements(c);
.  }

<p<blockquote>‍

ucol_next() returns the collation order of the next. ucol_prev() returns the collation order of the previous character. The Collation Element Iterator moves only in one direction between calls to ucol_reset. That is, ucol_next() and ucol_prev can not be inter-used. Whenever ucol_prev is to be called after ucol_next() or vice versa, ucol_reset has to be called first to reset the status, shifting pointers to either the end or the start of the string. Hence at the next call of ucol_prev or ucol_next, the first or last collation order will be returned. If a change of direction is done without a ucol_reset, the result is undefined. The result of a forward iterate (ucol_next) and reversed result of the
backward iterate (ucol_prev) on the same string are equivalent, if collation orders with the value 0 are ignored. Character based on the comparison level of the collator. A collation order consists of primary order, secondary order and tertiary order. The data type of the collation order is int32_t.

See also: UCollator

Definition in file ucoleitr.h.

Macro Definition Documentation

◆ UCOL_NULLORDER

#define UCOL_NULLORDER ((int32_t)0xFFFFFFFF)

This indicates an error has occurred during processing or if no more CEs is to be returned.

Stable:: ICU 2.0

Definition at line 30 of file ucoleitr.h.

Typedef Documentation

◆ UCollationElements

typedef struct UCollationElements UCollationElements

The UCollationElements struct.

For usage in C programs.

Stable:: ICU 2.0

Definition at line 39 of file ucoleitr.h.

Function Documentation

◆ ucol_closeElements()

U_CAPI void ucol_closeElements ( UCollationElements * elems )

Close a UCollationElements.

Once closed, a UCollationElements may no longer be used.

Parameters

elems The UCollationElements to close.

Stable:: ICU 2.0

◆ ucol_getMaxExpansion()

U_CAPI int32_t ucol_getMaxExpansion	(	const UCollationElements *	elems,
		int32_t	order
	)

Get the maximum length of any expansion sequences that end with the specified comparison order.

This is useful for .... ?

Parameters

elems	The UCollationElements containing the text.
order	A collation order returned by previous or next.

Returns: maximum size of the expansion sequences ending with the collation element or 1 if collation element does not occur at the end of any expansion sequence

Stable:: ICU 2.0

◆ ucol_getOffset()

U_CAPI int32_t ucol_getOffset ( const UCollationElements * elems )

Get the offset of the current source character.

This is an offset into the text of the character containing the current collation elements.

Parameters

elems The UCollationElements to query.

Returns: The offset of the current source character.

See also: ucol_setOffset

Stable:: ICU 2.0

◆ ucol_keyHashCode()

U_CAPI int32_t ucol_keyHashCode	(	const uint8_t *	key,
		int32_t	length
	)

get a hash code for a key... Not very useful!

Parameters

key	the given key.
length	the size of the key array.

Returns: the hash code.

Stable:: ICU 2.0

◆ ucol_next()

U_CAPI int32_t ucol_next	(	UCollationElements *	elems,
		UErrorCode *	status
	)

Get the ordering priority of the next collation element in the text.

A single character may contain more than one collation element.

Parameters

elems	The UCollationElements containing the text.
status	A pointer to a UErrorCode to receive any errors.

Returns: The next collation elements ordering, otherwise returns UCOL_NULLORDER if an error has occurred or if the end of string has been reached

Stable:: ICU 2.0

◆ ucol_openElements()

U_CAPI UCollationElements * ucol_openElements	(	const UCollator *	coll,
		const UChar *	text,
		int32_t	textLength,
		UErrorCode *	status
	)

Open the collation elements for a string.

The UCollationElements retains a pointer to the supplied text. The caller must not modify or delete the text while the UCollationElements object is used to iterate over this text.

Parameters

coll	The collator containing the desired collation rules.
text	The text to iterate over.
textLength	The number of characters in text, or -1 if null-terminated
status	A pointer to a UErrorCode to receive any errors.

Returns: a struct containing collation element information

Stable:: ICU 2.0

◆ ucol_previous()

U_CAPI int32_t ucol_previous	(	UCollationElements *	elems,
		UErrorCode *	status
	)

Get the ordering priority of the previous collation element in the text.

A single character may contain more than one collation element. Note that internally a stack is used to store buffered collation elements.

Parameters

elems	The UCollationElements containing the text.
status	A pointer to a UErrorCode to receive any errors. Notably a U_BUFFER_OVERFLOW_ERROR is returned if the internal stack buffer has been exhausted.

Returns: The previous collation elements ordering, otherwise returns UCOL_NULLORDER if an error has occurred or if the start of string has been reached.

Stable:: ICU 2.0

◆ ucol_primaryOrder()

U_CAPI int32_t ucol_primaryOrder ( int32_t order )

Get the primary order of a collation order.

Parameters

order the collation order

Returns: the primary order of a collation order.

Stable:: ICU 2.6

◆ ucol_reset()

U_CAPI void ucol_reset ( UCollationElements * elems )

Reset the collation elements to their initial state.

This will move the 'cursor' to the beginning of the text. Property settings for collation will be reset to the current status.

Parameters

elems The UCollationElements to reset.

See also: ucol_next; ucol_previous

Stable:: ICU 2.0

◆ ucol_secondaryOrder()

U_CAPI int32_t ucol_secondaryOrder ( int32_t order )

Get the secondary order of a collation order.

Parameters

order the collation order

Returns: the secondary order of a collation order.

Stable:: ICU 2.6

◆ ucol_setOffset()

U_CAPI void ucol_setOffset	(	UCollationElements *	elems,
		int32_t	offset,
		UErrorCode *	status
	)

Set the offset of the current source character.

This is an offset into the text of the character to be processed. Property settings for collation will remain the same. In order to reset the iterator to the current collation property settings, the API reset() has to be called.

Parameters

elems	The UCollationElements to set.
offset	The desired character offset.
status	A pointer to a UErrorCode to receive any errors.

See also: ucol_getOffset

Stable:: ICU 2.0

◆ ucol_setText()

U_CAPI void ucol_setText	(	UCollationElements *	elems,
		const UChar *	text,
		int32_t	textLength,
		UErrorCode *	status
	)

Set the text containing the collation elements.

Property settings for collation will remain the same. In order to reset the iterator to the current collation property settings, the API reset() has to be called.

The UCollationElements retains a pointer to the supplied text. The caller must not modify or delete the text while the UCollationElements object is used to iterate over this text.

Parameters

elems	The UCollationElements to set.
text	The source text containing the collation elements.
textLength	The length of text, or -1 if null-terminated.
status	A pointer to a UErrorCode to receive any errors.

See also: ucol_getText

Stable:: ICU 2.0

◆ ucol_tertiaryOrder()

U_CAPI int32_t ucol_tertiaryOrder ( int32_t order )

Get the tertiary order of a collation order.

Parameters

order the collation order

Returns: the tertiary order of a collation order.

Stable:: ICU 2.6

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ UCOL_NULLORDER

Typedef Documentation

◆ UCollationElements

Function Documentation

◆ ucol_closeElements()

◆ ucol_getMaxExpansion()

◆ ucol_getOffset()

◆ ucol_keyHashCode()

◆ ucol_next()

◆ ucol_openElements()

◆ ucol_previous()

◆ ucol_primaryOrder()

◆ ucol_reset()

◆ ucol_secondaryOrder()

◆ ucol_setOffset()

◆ ucol_setText()

◆ ucol_tertiaryOrder()