Inheritance diagram for UNormalize:
Public Types | |
enum | Mode { None = 1, NFD = 2, NFKD = 3, NFC = 4, Default = NFC, NFKC = 5, FCD = 6, Count } |
enum | Check { No, Yes, Maybe } |
enum | Options { None = 1, Unicode32 = 0x20 } |
Static Public Member Functions | |
void | normalize (UText src, UString dst, Mode mode, Options o=Options.None) |
Check | check (UText t, Mode mode, Options o=Options.None) |
bool | isNormalized (UText t, Mode mode, Options o=Options.None) |
void | concatenate (UText left, UText right, UString dst, Mode mode, Options o=Options.None) |
int | compare (UText left, UText right, Options o=Options.None) |
this () | |
~this () | |
Static Public Attributes | |
FunctionLoader Bind[] | targets |
Private Types | |
typedef void * | Handle |
enum | Error { OK, BufferOverflow = 15 } |
Static Private Member Functions | |
bool | isError (Error e) |
void | testError (Error e, char[] msg) |
char * | toString (char[] string) |
wchar * | toString (wchar[] string) |
uint | length (char *s) |
uint | length (wchar *s) |
char[] | toArray (char *s) |
wchar[] | toArray (wchar *s) |
Static Private Attributes | |
void * | library |
Characters with accents or other adornments can be encoded in several different ways in Unicode. For example, take the character 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
To a user of your program, however, both of these sequences should be treated as the same "user-level" character "A with acute accent". 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
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.
unorm_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, UNormalize rearranges accents into the proper canonical order, so that you do not have to worry about accent rearrangement on your own.
Form FCD, "Fast C or D", is also designed for collation. It allows to work on strings that are not necessarily normalized with an algorithm (like in collation) that works under "canonical closure", i.e., it treats precomposed characters and their decomposed equivalents the same.
It is not a normalization form because it does not provide for uniqueness of representation. Multiple strings may be canonically equivalent (their NFDs are identical) and may all conform to FCD without being identical themselves.
The form is defined such that the "raw decomposition", the recursive canonical decomposition of each character, results in a string that is canonically ordered. This means that precomposed characters are allowed for as long as their decompositions do not need canonical reordering.
Its advantage for a process like collation is that all NFD and most NFC texts - and many unnormalized texts - already conform to FCD and do not need to be normalized (NFD) for such a process. The FCD quick check will return UNORM_YES for most strings in practice.
For more details on FCD see the collation design document: http://oss.software.ibm.com/cvs/icu/~checkout~/icuhtml/design/collation/ICU_collation_design.htm
ICU collation performs either NFD or FCD normalization automatically if normalization is turned on for the collator object. Beyond collation and string search, normalized strings may be useful for string equivalence comparisons, transliteration/ transcription, unique representations, etc.
The W3C generally recommends to exchange texts in NFC. Note also that most legacy character encodings use only precomposed forms and often do not encode any combining marks by themselves. For conversion to such character encodings the Unicode text needs to be normalized to NFC. For more usage examples, see the Unicode Standard Annex.
See this page for full details.
Definition at line 189 of file UNormalize.d.
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Use this for the primary argument-type to most ICU functions |
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Definition at line 191 of file UNormalize.d. |
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Definition at line 203 of file UNormalize.d. Referenced by check(). |
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Definition at line 210 of file UNormalize.d. |
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ICU error codes (the ones which are referenced) |
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Definition at line 387 of file UNormalize.d. |
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Normalize a string. The string will be normalized according the specified normalization mode and options Definition at line 223 of file UNormalize.d. References UText::get(), UText::len, and len. |
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Performing quick check on a string, to quickly determine if the string is in a particular normalization format. Three types of result can be returned: Yes, No or Maybe. Result Yes indicates that the argument string is in the desired normalized format, No determines that argument string is not in the desired normalized format. A Maybe result indicates that a more thorough check is required, the user may have to put the string in its normalized form and compare the results. Definition at line 248 of file UNormalize.d. References Check, UText::get(), UText::len, and ICU::testError(). |
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Test if a string is in a given normalization form. Unlike check(), this function returns a definitive result, never a "maybe". For NFD, NFKD, and FCD, both functions work exactly the same. For NFC and NFKC where quickCheck may return "maybe", this function will perform further tests to arrive at a TRUE/FALSE result. Definition at line 269 of file UNormalize.d. References UText::get(), UText::len, and ICU::testError(). |
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Concatenate normalized strings, making sure that the result is normalized as well. If both the left and the right strings are in the normalization form according to "mode/options", then the result will be dest=normalize(left+right, mode, options) With the input strings already being normalized, this function will use unorm_next() and unorm_previous() to find the adjacent end pieces of the input strings. Only the concatenation of these end pieces will be normalized and then concatenated with the remaining parts of the input strings. It is allowed to have dst==left to avoid copying the entire left string. Definition at line 298 of file UNormalize.d. References UString::format(), UText::get(), UText::len, and len. |
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Compare two strings for canonical equivalence. Further options include case-insensitive comparison and code point order (as opposed to code unit order). Canonical equivalence between two strings is defined as their normalized forms (NFD or NFC) being identical. This function compares strings incrementally instead of normalizing (and optionally case-folding) both strings entirely, improving performance significantly. Bulk normalization is only necessary if the strings do not fulfill the FCD conditions. Only in this case, and only if the strings are relatively long, is memory allocated temporarily. For FCD strings and short non-FCD strings there is no memory allocation. Definition at line 328 of file UNormalize.d. References UText::get(), UText::len, and ICU::testError(). |
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Definition at line 378 of file UNormalize.d. |
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Definition at line 158 of file ICU.d. Referenced by UConverter::detectSignature(), UString::format(), UCollator::getLocale(), and UConverter::this(). |
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Definition at line 208 of file ICU.d. References string. |
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Definition at line 230 of file ICU.d. References strlen(). |
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Definition at line 239 of file ICU.d. References wcslen(). |
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Definition at line 248 of file ICU.d. References strlen(). Referenced by UConverter::detectSignature(), UResourceBundle::getKey(), UResourceBundle::getLocale(), UMessageFormat::getLocale(), UCollator::getLocale(), UConverter::getName(), UChar::getPropertyName(), UChar::getPropertyValueName(), and UConverter::opApply(). |
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Definition at line 259 of file ICU.d. References wcslen(). |
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Bind the ICU functions from a shared library. This is complicated by the issues regarding D and DLLs on the Windows platform Definition at line 346 of file UNormalize.d. |
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Initial value: [ {cast(void**) &unorm_normalize, "unorm_normalize"} Definition at line 365 of file UNormalize.d. |