This include file defines functions for case mapping for Unicode strings and
case insensitive comparison of Unicode strings and C strings.
These string functions fix the problems that were mentioned in
‘char *’ strings, namely, they handle the Croatian
LETTER DZ WITH CARON, the German LATIN SMALL LETTER SHARP S, the
Greek sigma and the Lithuanian i correctly.
The following functions implement case mappings on Unicode characters —
for those cases only where the result of the mapping is a again a single
Unicode character.
These mappings are locale and context independent.
|
WARNING! These functions are not sufficient for languages such as
German, Greek and Lithuanian. Better use the functions below that treat an
entire string at once and are language aware.
|
- Function: ucs4_t uc_toupper (ucs4_t uc)
Returns the uppercase mapping of the Unicode character uc.
- Function: ucs4_t uc_tolower (ucs4_t uc)
Returns the lowercase mapping of the Unicode character uc.
- Function: ucs4_t uc_totitle (ucs4_t uc)
Returns the titlecase mapping of the Unicode character uc.
The titlecase mapping of a character is to be used when the character should
look like upper case and the following characters are lower cased.
For most characters, this is the same as the uppercase mapping. There are
only few characters where the title case variant and the uuper case variant
are different. These characters occur in the Latin writing of the Croatian,
Bosnian, and Serbian languages.
Lower case | Title case | Upper case
|
|---|
LATIN SMALL LETTER LJ
| LATIN CAPITAL LETTER L WITH SMALL LETTER J
| LATIN CAPITAL LETTER LJ
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LATIN SMALL LETTER NJ
| LATIN CAPITAL LETTER N WITH SMALL LETTER J
| LATIN CAPITAL LETTER NJ
|
LATIN SMALL LETTER DZ
| LATIN CAPITAL LETTER D WITH SMALL LETTER Z
| LATIN CAPITAL LETTER DZ
|
LATIN SMALL LETTER DZ WITH CARON
| LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
| LATIN CAPITAL LETTER DZ WITH CARON
|
Case mapping should always be performed on entire strings, not on individual
characters. The functions in this sections do so.
These functions allow to apply a normalization after the case mapping. The
reason is that if you want to treat ‘ä’ and ‘Ä’ the same,
you most often also want to treat the composed and decomposed forms of such
a character, U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS and
U+0041 LATIN CAPITAL LETTER A U+0308 COMBINING DIAERESIS the same.
The nf argument designates the normalization.
These functions are locale dependent. The iso639_language argument
identifies the language (e.g. "tr" for Turkish). NULL means to use
locale independent case mappings.
- Function: const char * uc_locale_language ()
Returns the ISO 639 language code of the current locale.
Returns "" if it is unknown, or in the "C" locale.
- Function: uint8_t * u8_toupper (const uint8_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_toupper (const uint16_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_toupper (const uint32_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the uppercase mapping of a string.
The nf argument identifies the normalization form to apply after the
case-mapping. It can also be NULL, for no normalization.
- Function: uint8_t * u8_tolower (const uint8_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_tolower (const uint16_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_tolower (const uint32_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the lowercase mapping of a string.
The nf argument identifies the normalization form to apply after the
case-mapping. It can also be NULL, for no normalization.
- Function: uint8_t * u8_totitle (const uint8_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_totitle (const uint16_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_totitle (const uint32_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the titlecase mapping of a string.
Mapping to title case means that, in each word, the first cased character
is being mapped to title case and the remaining characters of the word
are being mapped to lower case.
The nf argument identifies the normalization form to apply after the
case-mapping. It can also be NULL, for no normalization.
Case mapping of a substring cannot simply be performed by extracting the
substring and then applying the case mapping function to it. This does not
work because case mapping requires some information about the surrounding
characters. The following functions allow to apply case mappings to
substrings of a given string, while taking into account the characters that
precede it (the “prefix”) and the characters that follow it (the “suffix”).
- Type: casing_prefix_context_t
This data type denotes the case-mapping context that is given by a prefix
string. It is an immediate type that can be copied by simple assignment,
without involving memory allocation. It is not an array type.
- Constant: casing_prefix_context_t unicase_empty_prefix_context
This constant is the case-mapping context that corresponds to an empty prefix
string.
The following functions return casing_prefix_context_t objects:
- Function: casing_prefix_context_t u8_casing_prefix_context (const uint8_t *s, size_t n)
- Function: casing_prefix_context_t u16_casing_prefix_context (const uint16_t *s, size_t n)
- Function: casing_prefix_context_t u32_casing_prefix_context (const uint32_t *s, size_t n)
Returns the case-mapping context of a given prefix string.
- Function: casing_prefix_context_t u8_casing_prefixes_context (const uint8_t *s, size_t n, casing_prefix_context_t a_context)
- Function: casing_prefix_context_t u16_casing_prefixes_context (const uint16_t *s, size_t n, casing_prefix_context_t a_context)
- Function: casing_prefix_context_t u32_casing_prefixes_context (const uint32_t *s, size_t n, casing_prefix_context_t a_context)
Returns the case-mapping context of the prefix concat(a, s),
given the case-mapping context of the prefix a.
- Type: casing_suffix_context_t
This data type denotes the case-mapping context that is given by a suffix
string. It is an immediate type that can be copied by simple assignment,
without involving memory allocation. It is not an array type.
- Constant: casing_suffix_context_t unicase_empty_suffix_context
This constant is the case-mapping context that corresponds to an empty suffix
string.
The following functions return casing_suffix_context_t objects:
- Function: casing_suffix_context_t u8_casing_suffix_context (const uint8_t *s, size_t n)
- Function: casing_suffix_context_t u16_casing_suffix_context (const uint16_t *s, size_t n)
- Function: casing_suffix_context_t u32_casing_suffix_context (const uint32_t *s, size_t n)
Returns the case-mapping context of a given suffix string.
- Function: casing_suffix_context_t u8_casing_suffixes_context (const uint8_t *s, size_t n, casing_suffix_context_t a_context)
- Function: casing_suffix_context_t u16_casing_suffixes_context (const uint16_t *s, size_t n, casing_suffix_context_t a_context)
- Function: casing_suffix_context_t u32_casing_suffixes_context (const uint32_t *s, size_t n, casing_suffix_context_t a_context)
Returns the case-mapping context of the suffix concat(s, a),
given the case-mapping context of the suffix a.
The following functions perform a case mapping, considering the
prefix context and the suffix context.
- Function: uint8_t * u8_ct_toupper (const uint8_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_ct_toupper (const uint16_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_ct_toupper (const uint32_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the uppercase mapping of a string that is surrounded by a prefix
and a suffix.
- Function: uint8_t * u8_ct_tolower (const uint8_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_ct_tolower (const uint16_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_ct_tolower (const uint32_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the lowercase mapping of a string that is surrounded by a prefix
and a suffix.
- Function: uint8_t * u8_ct_totitle (const uint8_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_ct_totitle (const uint16_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_ct_totitle (const uint32_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the titlecase mapping of a string that is surrounded by a prefix
and a suffix.
For example, to uppercase the UTF-8 substring between s + start_index
and s + end_index of a string that extends from s to
s + u8_strlen (s), you can use the statements
| | size_t result_length;
uint8_t result =
u8_ct_toupper (s + start_index, end_index - start_index,
u8_casing_prefix_context (s, start_index),
u8_casing_suffix_context (s + end_index,
u8_strlen (s) - end_index),
iso639_language, NULL, NULL, &result_length);
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The following functions implement comparison that ignores differences in case
and normalization.
- Function: uint8_t * u8_casefold (const uint8_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_casefold (const uint16_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_casefold (const uint32_t *s, size_t n, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the case folded string.
Comparing u8_casefold (s1) and u8_casefold (s2)
with the u8_cmp2 function is equivalent to comparing s1 and
s2 with u8_casecmp.
The nf argument identifies the normalization form to apply after the
case-mapping. It can also be NULL, for no normalization.
- Function: uint8_t * u8_ct_casefold (const uint8_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint8_t *resultbuf, size_t *lengthp)
- Function: uint16_t * u16_ct_casefold (const uint16_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint16_t *resultbuf, size_t *lengthp)
- Function: uint32_t * u32_ct_casefold (const uint32_t *s, size_t n, casing_prefix_context_t prefix_context, casing_suffix_context_t suffix_context, const char *iso639_language, uninorm_t nf, uint32_t *resultbuf, size_t *lengthp)
Returns the case folded string. The case folding takes into account the
case mapping contexts of the prefix and suffix strings.
- Function: int u8_casecmp (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int u16_casecmp (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int u32_casecmp (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int ulc_casecmp (const char *s1, size_t n1, const char *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
Compares s1 and s2, ignoring differences in case and normalization.
The nf argument identifies the normalization form to apply after the
case-mapping. It can also be NULL, for no normalization.
If successful, sets *resultp to -1 if s1 < s2,
0 if s1 = s2, 1 if s1 > s2, and returns 0.
Upon failure, returns -1 with errno set.
The following functions additionally take into account the sorting rules of the
current locale.
- Function: char * u8_casexfrm (const uint8_t *s, size_t n, const char *iso639_language, uninorm_t nf, char *resultbuf, size_t *lengthp)
- Function: char * u16_casexfrm (const uint16_t *s, size_t n, const char *iso639_language, uninorm_t nf, char *resultbuf, size_t *lengthp)
- Function: char * u32_casexfrm (const uint32_t *s, size_t n, const char *iso639_language, uninorm_t nf, char *resultbuf, size_t *lengthp)
- Function: char * ulc_casexfrm (const char *s, size_t n, const char *iso639_language, uninorm_t nf, char *resultbuf, size_t *lengthp)
Converts the string s of length n to a NUL-terminated byte
sequence, in such a way that comparing u8_casexfrm (s1) and
u8_casexfrm (s2) with the gnulib function memcmp2 is
equivalent to comparing s1 and s2 with u8_casecoll.
nf must be either UNINORM_NFC, UNINORM_NFKC, or NULL for
no normalization.
- Function: int u8_casecoll (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int u16_casecoll (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int u32_casecoll (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
- Function: int ulc_casecoll (const char *s1, size_t n1, const char *s2, size_t n2, const char *iso639_language, uninorm_t nf, int *resultp)
Compares s1 and s2, ignoring differences in case and normalization,
using the collation rules of the current locale.
The nf argument identifies the normalization form to apply after the
case-mapping. It must be either UNINORM_NFC or UNINORM_NFKC.
It can also be NULL, for no normalization.
If successful, sets *resultp to -1 if s1 < s2,
0 if s1 = s2, 1 if s1 > s2, and returns 0.
Upon failure, returns -1 with errno set.
The following functions determine whether a Unicode string is entirely in
upper case. or entirely in lower case, or entirely in title case, or already
case-folded.
- Function: int u8_is_uppercase (const uint8_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u16_is_uppercase (const uint16_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u32_is_uppercase (const uint32_t *s, size_t n, const char *iso639_language, bool *resultp)
Sets *resultp to true if mapping NFD(s) to upper case is
a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
errno set.
- Function: int u8_is_lowercase (const uint8_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u16_is_lowercase (const uint16_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u32_is_lowercase (const uint32_t *s, size_t n, const char *iso639_language, bool *resultp)
Sets *resultp to true if mapping NFD(s) to lower case is
a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
errno set.
- Function: int u8_is_titlecase (const uint8_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u16_is_titlecase (const uint16_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u32_is_titlecase (const uint32_t *s, size_t n, const char *iso639_language, bool *resultp)
Sets *resultp to true if mapping NFD(s) to title case is
a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
errno set.
- Function: int u8_is_casefolded (const uint8_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u16_is_casefolded (const uint16_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u32_is_casefolded (const uint32_t *s, size_t n, const char *iso639_language, bool *resultp)
Sets *resultp to true if applying case folding to NFD(S) is
a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
errno set.
The following functions determine whether case mappings have any effect on a
Unicode string.
- Function: int u8_is_cased (const uint8_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u16_is_cased (const uint16_t *s, size_t n, const char *iso639_language, bool *resultp)
- Function: int u32_is_cased (const uint32_t *s, size_t n, const char *iso639_language, bool *resultp)
Sets *resultp to true if case matters for s, that is, if
mapping NFD(s) to either upper case or lower case or title case is not
a no-op. Set *resultp to false if NFD(s) maps to itself
under the upper case mapping, under the lower case mapping, and under the title
case mapping; in other words, when NFD(s) consists entirely of caseless
characters. Upon failure, returns -1 with errno set.
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