2 @chapter Case mappings @code{<unicase.h>}
4 This include file defines functions for case mapping for Unicode strings and
5 case insensitive comparison of Unicode strings and C strings.
7 These string functions fix the problems that were mentioned in
8 @ref{char * strings}, namely, they handle the Croatian
9 @sc{LETTER DZ WITH CARON}, the German @sc{LATIN SMALL LETTER SHARP S}, the
10 Greek sigma and the Lithuanian i correctly.
13 * Case mappings of characters::
14 * Case mappings of strings::
15 * Case mappings of substrings::
16 * Case insensitive comparison::
20 @node Case mappings of characters
21 @section Case mappings of characters
23 @cindex Unicode character, case mappings
24 The following functions implement case mappings on Unicode characters ---
25 for those cases only where the result of the mapping is a again a single
28 These mappings are locale and context independent.
31 @strong{WARNING!} These functions are not sufficient for languages such as
32 German, Greek and Lithuanian. Better use the functions below that treat an
33 entire string at once and are language aware.
36 @deftypefun ucs4_t uc_toupper (ucs4_t @var{uc})
37 Returns the uppercase mapping of the Unicode character @var{uc}.
40 @deftypefun ucs4_t uc_tolower (ucs4_t @var{uc})
41 Returns the lowercase mapping of the Unicode character @var{uc}.
44 @deftypefun ucs4_t uc_totitle (ucs4_t @var{uc})
45 Returns the titlecase mapping of the Unicode character @var{uc}.
47 The titlecase mapping of a character is to be used when the character should
48 look like upper case and the following characters are lower cased.
50 For most characters, this is the same as the uppercase mapping. There are
51 only few characters where the title case variant and the uuper case variant
52 are different. These characters occur in the Latin writing of the Croatian,
53 Bosnian, and Serbian languages.
55 @c Normally we would use .33 space for each column, but this is too much in
57 @c <http://lists.gnu.org/archive/html/bug-texinfo/2009-05/msg00016.html>.
58 @multitable @columnfractions .31 .31 .31
59 @headitem Lower case @tab Title case @tab Upper case
60 @item LATIN SMALL LETTER LJ
61 @tab LATIN CAPITAL LETTER L WITH SMALL LETTER J
62 @tab LATIN CAPITAL LETTER LJ
63 @item LATIN SMALL LETTER NJ
64 @tab LATIN CAPITAL LETTER N WITH SMALL LETTER J
65 @tab LATIN CAPITAL LETTER NJ
66 @item LATIN SMALL LETTER DZ
67 @tab LATIN CAPITAL LETTER D WITH SMALL LETTER Z
68 @tab LATIN CAPITAL LETTER DZ
69 @item LATIN SMALL LETTER DZ WITH CARON
70 @tab LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON
71 @tab LATIN CAPITAL LETTER DZ WITH CARON
75 @node Case mappings of strings
76 @section Case mappings of strings
82 Case mapping should always be performed on entire strings, not on individual
83 characters. The functions in this sections do so.
85 These functions allow to apply a normalization after the case mapping. The
86 reason is that if you want to treat @samp{@"{a}} and @samp{@"{A}} the same,
87 you most often also want to treat the composed and decomposed forms of such
88 a character, U+00C4 @sc{LATIN CAPITAL LETTER A WITH DIAERESIS} and
89 U+0041 @sc{LATIN CAPITAL LETTER A} U+0308 @sc{COMBINING DIAERESIS} the same.
90 The @var{nf} argument designates the normalization.
92 @cindex locale language
93 These functions are locale dependent. The @var{iso639_language} argument
94 identifies the language (e.g@. @code{"tr"} for Turkish). NULL means to use
95 locale independent case mappings.
97 @deftypefun {const char *} uc_locale_language ()
98 Returns the ISO 639 language code of the current locale.
99 Returns @code{""} if it is unknown, or in the "C" locale.
102 @deftypefun {uint8_t *} u8_toupper (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
103 @deftypefunx {uint16_t *} u16_toupper (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
104 @deftypefunx {uint32_t *} u32_toupper (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
105 Returns the uppercase mapping of a string.
107 The @var{nf} argument identifies the normalization form to apply after the
108 case-mapping. It can also be NULL, for no normalization.
111 @deftypefun {uint8_t *} u8_tolower (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
112 @deftypefunx {uint16_t *} u16_tolower (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
113 @deftypefunx {uint32_t *} u32_tolower (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
114 Returns the lowercase mapping of a string.
116 The @var{nf} argument identifies the normalization form to apply after the
117 case-mapping. It can also be NULL, for no normalization.
120 @deftypefun {uint8_t *} u8_totitle (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
121 @deftypefunx {uint16_t *} u16_totitle (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
122 @deftypefunx {uint32_t *} u32_totitle (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
123 Returns the titlecase mapping of a string.
125 Mapping to title case means that, in each word, the first cased character
126 is being mapped to title case and the remaining characters of the word
127 are being mapped to lower case.
129 The @var{nf} argument identifies the normalization form to apply after the
130 case-mapping. It can also be NULL, for no normalization.
133 @node Case mappings of substrings
134 @section Case mappings of substrings
136 Case mapping of a substring cannot simply be performed by extracting the
137 substring and then applying the case mapping function to it. This does not
138 work because case mapping requires some information about the surrounding
139 characters. The following functions allow to apply case mappings to
140 substrings of a given string, while taking into account the characters that
141 precede it (the ``prefix'') and the characters that follow it (the ``suffix'').
143 @deftp Type casing_prefix_context_t
144 This data type denotes the case-mapping context that is given by a prefix
145 string. It is an immediate type that can be copied by simple assignment,
146 without involving memory allocation. It is not an array type.
149 @deftypevr Constant casing_prefix_context_t unicase_empty_prefix_context
150 This constant is the case-mapping context that corresponds to an empty prefix
154 The following functions return @code{casing_prefix_context_t} objects:
156 @deftypefun casing_prefix_context_t u8_casing_prefix_context (const uint8_t *@var{s}, size_t @var{n})
157 @deftypefunx casing_prefix_context_t u16_casing_prefix_context (const uint16_t *@var{s}, size_t @var{n})
158 @deftypefunx casing_prefix_context_t u32_casing_prefix_context (const uint32_t *@var{s}, size_t @var{n})
159 Returns the case-mapping context of a given prefix string.
162 @deftypefun casing_prefix_context_t u8_casing_prefixes_context (const uint8_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{a_context})
163 @deftypefunx casing_prefix_context_t u16_casing_prefixes_context (const uint16_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{a_context})
164 @deftypefunx casing_prefix_context_t u32_casing_prefixes_context (const uint32_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{a_context})
165 Returns the case-mapping context of the prefix concat(@var{a}, @var{s}),
166 given the case-mapping context of the prefix @var{a}.
169 @deftp Type casing_suffix_context_t
170 This data type denotes the case-mapping context that is given by a suffix
171 string. It is an immediate type that can be copied by simple assignment,
172 without involving memory allocation. It is not an array type.
175 @deftypevr Constant casing_suffix_context_t unicase_empty_suffix_context
176 This constant is the case-mapping context that corresponds to an empty suffix
180 The following functions return @code{casing_suffix_context_t} objects:
182 @deftypefun casing_suffix_context_t u8_casing_suffix_context (const uint8_t *@var{s}, size_t @var{n})
183 @deftypefunx casing_suffix_context_t u16_casing_suffix_context (const uint16_t *@var{s}, size_t @var{n})
184 @deftypefunx casing_suffix_context_t u32_casing_suffix_context (const uint32_t *@var{s}, size_t @var{n})
185 Returns the case-mapping context of a given suffix string.
188 @deftypefun casing_suffix_context_t u8_casing_suffixes_context (const uint8_t *@var{s}, size_t @var{n}, casing_suffix_context_t @var{a_context})
189 @deftypefunx casing_suffix_context_t u16_casing_suffixes_context (const uint16_t *@var{s}, size_t @var{n}, casing_suffix_context_t @var{a_context})
190 @deftypefunx casing_suffix_context_t u32_casing_suffixes_context (const uint32_t *@var{s}, size_t @var{n}, casing_suffix_context_t @var{a_context})
191 Returns the case-mapping context of the suffix concat(@var{s}, @var{a}),
192 given the case-mapping context of the suffix @var{a}.
195 The following functions perform a case mapping, considering the
196 prefix context and the suffix context.
198 @deftypefun {uint8_t *} u8_ct_toupper (const uint8_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
199 @deftypefunx {uint16_t *} u16_ct_toupper (const uint16_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
200 @deftypefunx {uint32_t *} u32_ct_toupper (const uint32_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
201 Returns the uppercase mapping of a string that is surrounded by a prefix
205 @deftypefun {uint8_t *} u8_ct_tolower (const uint8_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
206 @deftypefunx {uint16_t *} u16_ct_tolower (const uint16_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
207 @deftypefunx {uint32_t *} u32_ct_tolower (const uint32_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
208 Returns the lowercase mapping of a string that is surrounded by a prefix
212 @deftypefun {uint8_t *} u8_ct_totitle (const uint8_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
213 @deftypefunx {uint16_t *} u16_ct_totitle (const uint16_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
214 @deftypefunx {uint32_t *} u32_ct_totitle (const uint32_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
215 Returns the titlecase mapping of a string that is surrounded by a prefix
219 For example, to uppercase the UTF-8 substring between @code{s + start_index}
220 and @code{s + end_index} of a string that extends from @code{s} to
221 @code{s + u8_strlen (s)}, you can use the statements
224 size_t result_length;
226 u8_ct_toupper (s + start_index, end_index - start_index,
227 u8_casing_prefix_context (s, start_index),
228 u8_casing_suffix_context (s + end_index,
229 u8_strlen (s) - end_index),
230 iso639_language, NULL, NULL, &result_length);
233 @node Case insensitive comparison
234 @section Case insensitive comparison
236 @cindex comparing, ignoring case
237 @cindex comparing, ignoring normalization and case
238 The following functions implement comparison that ignores differences in case
241 @deftypefun {uint8_t *} u8_casefold (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
242 @deftypefunx {uint16_t *} u16_casefold (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
243 @deftypefunx {uint32_t *} u32_casefold (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
244 Returns the case folded string.
246 Comparing @code{u8_casefold (@var{s1})} and @code{u8_casefold (@var{s2})}
247 with the @code{u8_cmp2} function is equivalent to comparing @var{s1} and
248 @var{s2} with @code{u8_casecmp}.
250 The @var{nf} argument identifies the normalization form to apply after the
251 case-mapping. It can also be NULL, for no normalization.
254 @deftypefun {uint8_t *} u8_ct_casefold (const uint8_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint8_t *@var{resultbuf}, size_t *@var{lengthp})
255 @deftypefunx {uint16_t *} u16_ct_casefold (const uint16_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint16_t *@var{resultbuf}, size_t *@var{lengthp})
256 @deftypefunx {uint32_t *} u32_ct_casefold (const uint32_t *@var{s}, size_t @var{n}, casing_prefix_context_t @var{prefix_context}, casing_suffix_context_t @var{suffix_context}, const char *@var{iso639_language}, uninorm_t @var{nf}, uint32_t *@var{resultbuf}, size_t *@var{lengthp})
257 Returns the case folded string. The case folding takes into account the
258 case mapping contexts of the prefix and suffix strings.
261 @deftypefun int u8_casecmp (const uint8_t *@var{s1}, size_t @var{n1}, const uint8_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
262 @deftypefunx int u16_casecmp (const uint16_t *@var{s1}, size_t @var{n1}, const uint16_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
263 @deftypefunx int u32_casecmp (const uint32_t *@var{s1}, size_t @var{n1}, const uint32_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
264 @deftypefunx int ulc_casecmp (const char *@var{s1}, size_t @var{n1}, const char *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
265 Compares @var{s1} and @var{s2}, ignoring differences in case and normalization.
267 The @var{nf} argument identifies the normalization form to apply after the
268 case-mapping. It can also be NULL, for no normalization.
270 If successful, sets @code{*@var{resultp}} to -1 if @var{s1} < @var{s2},
271 0 if @var{s1} = @var{s2}, 1 if @var{s1} > @var{s2}, and returns 0.
272 Upon failure, returns -1 with @code{errno} set.
275 @cindex comparing, ignoring case, with collation rules
276 @cindex comparing, with collation rules, ignoring case
277 @cindex comparing, ignoring normalization and case, with collation rules
278 @cindex comparing, with collation rules, ignoring normalization and case
279 The following functions additionally take into account the sorting rules of the
282 @deftypefun {char *} u8_casexfrm (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, char *@var{resultbuf}, size_t *@var{lengthp})
283 @deftypefunx {char *} u16_casexfrm (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, char *@var{resultbuf}, size_t *@var{lengthp})
284 @deftypefunx {char *} u32_casexfrm (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, char *@var{resultbuf}, size_t *@var{lengthp})
285 @deftypefunx {char *} ulc_casexfrm (const char *@var{s}, size_t @var{n}, const char *@var{iso639_language}, uninorm_t @var{nf}, char *@var{resultbuf}, size_t *@var{lengthp})
286 Converts the string @var{s} of length @var{n} to a NUL-terminated byte
287 sequence, in such a way that comparing @code{u8_casexfrm (@var{s1})} and
288 @code{u8_casexfrm (@var{s2})} with the gnulib function @code{memcmp2} is
289 equivalent to comparing @var{s1} and @var{s2} with @code{u8_casecoll}.
291 @var{nf} must be either @code{UNINORM_NFC}, @code{UNINORM_NFKC}, or NULL for
295 @deftypefun int u8_casecoll (const uint8_t *@var{s1}, size_t @var{n1}, const uint8_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
296 @deftypefunx int u16_casecoll (const uint16_t *@var{s1}, size_t @var{n1}, const uint16_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
297 @deftypefunx int u32_casecoll (const uint32_t *@var{s1}, size_t @var{n1}, const uint32_t *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
298 @deftypefunx int ulc_casecoll (const char *@var{s1}, size_t @var{n1}, const char *@var{s2}, size_t @var{n2}, const char *@var{iso639_language}, uninorm_t @var{nf}, int *@var{resultp})
299 Compares @var{s1} and @var{s2}, ignoring differences in case and normalization,
300 using the collation rules of the current locale.
302 The @var{nf} argument identifies the normalization form to apply after the
303 case-mapping. It must be either @code{UNINORM_NFC} or @code{UNINORM_NFKC}.
304 It can also be NULL, for no normalization.
306 If successful, sets @code{*@var{resultp}} to -1 if @var{s1} < @var{s2},
307 0 if @var{s1} = @var{s2}, 1 if @var{s1} > @var{s2}, and returns 0.
308 Upon failure, returns -1 with @code{errno} set.
312 @section Case detection
314 @cindex case detection
315 @cindex detecting case
316 The following functions determine whether a Unicode string is entirely in
317 upper case. or entirely in lower case, or entirely in title case, or already
320 @deftypefun int u8_is_uppercase (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
321 @deftypefunx int u16_is_uppercase (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
322 @deftypefunx int u32_is_uppercase (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
323 Sets @code{*@var{resultp}} to true if mapping NFD(@var{s}) to upper case is
324 a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
328 @deftypefun int u8_is_lowercase (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
329 @deftypefunx int u16_is_lowercase (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
330 @deftypefunx int u32_is_lowercase (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
331 Sets @code{*@var{resultp}} to true if mapping NFD(@var{s}) to lower case is
332 a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
336 @deftypefun int u8_is_titlecase (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
337 @deftypefunx int u16_is_titlecase (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
338 @deftypefunx int u32_is_titlecase (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
339 Sets @code{*@var{resultp}} to true if mapping NFD(@var{s}) to title case is
340 a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
344 @deftypefun int u8_is_casefolded (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
345 @deftypefunx int u16_is_casefolded (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
346 @deftypefunx int u32_is_casefolded (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
347 Sets @code{*@var{resultp}} to true if applying case folding to NFD(@var{S}) is
348 a no-op, or to false otherwise, and returns 0. Upon failure, returns -1 with
352 The following functions determine whether case mappings have any effect on a
355 @deftypefun int u8_is_cased (const uint8_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
356 @deftypefunx int u16_is_cased (const uint16_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
357 @deftypefunx int u32_is_cased (const uint32_t *@var{s}, size_t @var{n}, const char *@var{iso639_language}, bool *@var{resultp})
358 Sets @code{*@var{resultp}} to true if case matters for @var{s}, that is, if
359 mapping NFD(@var{s}) to either upper case or lower case or title case is not
360 a no-op. Set @code{*@var{resultp}} to false if NFD(@var{s}) maps to itself
361 under the upper case mapping, under the lower case mapping, and under the title
362 case mapping; in other words, when NFD(@var{s}) consists entirely of caseless
363 characters. Upon failure, returns -1 with @code{errno} set.