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unorm.h File Reference

C API: Unicode Normalization. More...

#include "unicode/utypes.h"

Go to the source code of this file.

Typedefs

typedef UNormalizationMode UNormalizationOption
 Possible normalization options. More...


Enumerations

enum  UNormalizationMode {
  UCOL_NO_NORMALIZATION = 1, UCOL_DECOMP_CAN = 2, UCOL_DECOMP_COMPAT = 3, UCOL_DEFAULT_NORMALIZATION = UCOL_DECOMP_COMPAT,
  UCOL_DECOMP_CAN_COMP_COMPAT = 4, UCOL_DECOMP_COMPAT_COMP_CAN = 5, UNORM_NONE = 1, UNORM_NFD = 2,
  UNORM_NFKD = 3, UNORM_NFC = 4, UNORM_DEFAULT = UNORM_NFC, UNORM_NFKC = 5,
  UNORM_MODE_COUNT, UCOL_IGNORE_HANGUL = 16, UNORM_IGNORE_HANGUL = 16
}
 UCOL_NO_NORMALIZATION : Accented characters will not be decomposed for sorting. More...


Functions

U_CAPI int32_t u_normalize (const UChar* source, int32_t sourceLength, UNormalizationMode mode, int32_t options, UChar* result, int32_t resultLength, UErrorCode* status)
 Normalize a string. More...


Detailed Description

C API: Unicode Normalization.

Unicode normalization API

u_normalize transforms Unicode text into an equivalent composed or decomposed form, allowing for easier sorting and searching of text. u_normalize supports the standard normalization forms described in Unicode Technical Report #15.

Characters with accents or other adornments can be encoded in several different ways in Unicode. For example, take the character "Á" (A-acute). In Unicode, this can be encoded as a single character (the "composed" form):

 
      00C1    LATIN CAPITAL LETTER A WITH ACUTE
or as two separate characters (the "decomposed" form):
 
      0041    LATIN CAPITAL LETTER A
      0301    COMBINING ACUTE ACCENT</PRE>

To a user of your program, however, both of these sequences should be treated as the same "user-level" character "Á". When you are searching or comparing text, you must ensure that these two sequences are treated equivalently. In addition, you must handle characters with more than one accent. Sometimes the order of a character's combining accents is significant, while in other cases accent sequences in different orders are really equivalent.

Similarly, the string "ffi" can be encoded as three separate letters:

 
      0066    LATIN SMALL LETTER F
      0066    LATIN SMALL LETTER F
      0069    LATIN SMALL LETTER I
or as the single character
 
      FB03    LATIN SMALL LIGATURE FFI</PRE>

The ffi ligature is not a distinct semantic character, and strictly speaking it shouldn't be in Unicode at all, but it was included for compatibility with existing character sets that already provided it. The Unicode standard identifies such characters by giving them "compatibility" decompositions into the corresponding semantic characters. When sorting and searching, you will often want to use these mappings.

u_normalize helps solve these problems by transforming text into the canonical composed and decomposed forms as shown in the first example above. In addition, you can have it perform compatibility decompositions so that you can treat compatibility characters the same as their equivalents. Finally, u_normalize rearranges accents into the proper canonical order, so that you do not have to worry about accent rearrangement on your own.

u_normalize adds one optional behavior, #UCOL_IGNORE_HANGUL, that differs from the standard Unicode Normalization Forms.

Definition in file unorm.h.


Typedef Documentation

typedef UNormalizationMode UNormalizationOption
 

Possible normalization options.

Definition at line 130 of file unorm.h.


Enumeration Type Documentation

enum UNormalizationMode
 

UCOL_NO_NORMALIZATION : Accented characters will not be decomposed for sorting.

UCOL_DECOM_CAN : Characters that are canonical variants according to Unicode 2.0 will be decomposed for sorting. UCOL_DECOMP_COMPAT : Characters that are compatibility variants will be decomposed for sorting. This is the default normalization mode used. UCOL_DECOMP_CAN_COMP_COMPAT : Canonical decomposition followed by canonical composition UCOL_DECOMP_COMPAT_COMP_CAN : Compatibility decomposition followed by canonical composition

Enumeration values:
UCOL_NO_NORMALIZATION   No decomposition/composition.
UCOL_DECOMP_CAN   Canonical decomposition.
UCOL_DECOMP_COMPAT   Compatibility decomposition.
UCOL_DEFAULT_NORMALIZATION   Default normalization.
UCOL_DECOMP_CAN_COMP_COMPAT   Canonical decomposition followed by canonical composition.
UCOL_DECOMP_COMPAT_COMP_CAN   Compatibility decomposition followed by canonical composition.
UNORM_NONE   No decomposition/composition.
UNORM_NFD   Canonical decomposition.
UNORM_NFKD   Compatibility decomposition.
UNORM_NFC   Canonical decomposition followed by canonical composition.
UNORM_DEFAULT   Default normalization.
UNORM_NFKC   Compatibility decomposition followed by canonical composition.
UNORM_MODE_COUNT  
UCOL_IGNORE_HANGUL   Do not normalize Hangul.
UNORM_IGNORE_HANGUL  

Definition at line 96 of file unorm.h.


Function Documentation

U_CAPI int32_t u_normalize ( const UChar * source,
int32_t sourceLength,
UNormalizationMode mode,
int32_t options,
UChar * result,
int32_t resultLength,
UErrorCode * status )
 

Normalize a string.

The string will be normalized according the the specified normalization mode and options.

Parameters:
source   The string to normalize.
sourceLength   The length of source, or -1 if null-terminated.
mode   The normalization mode; one of UCOL_NO_NORMALIZATION, UCOL_CAN_DECOMP, UCOL_COMPAT_DECOMP, UCOL_CAN_DECOMP_COMPAT_COMP, UCOL_COMPAT_DECOMP_CAN_COMP, UCOL_DEFAULT_NORMALIZATION
options   The normalization options, ORed together; possible values are UCOL_IGNORE_HANGUL
result   A pointer to a buffer to receive the attribute.
resultLength   The maximum size of result.
status   A pointer to an UErrorCode to receive any errors
Returns:
The total buffer size needed; if greater than resultLength, the output was truncated.
Stable:


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