lib/uninorm.in.h

   1 /* Normalization forms (composition and decomposition) of Unicode strings.
   2    Copyright (C) 2001-2002, 2009-2020 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2009.
   4
   5    This program is free software: you can redistribute it and/or modify it
   6    under the terms of the GNU Lesser General Public License as published
   7    by the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _UNINORM_H
  19 #define _UNINORM_H
  20
  21 /* Get size_t.  */
  22 #include <stddef.h>
  23
  24 #include "unitypes.h"
  25
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31
  32 /* Conventions:
  33
  34    All functions prefixed with u8_ operate on UTF-8 encoded strings.
  35    Their unit is an uint8_t (1 byte).
  36
  37    All functions prefixed with u16_ operate on UTF-16 encoded strings.
  38    Their unit is an uint16_t (a 2-byte word).
  39
  40    All functions prefixed with u32_ operate on UCS-4 encoded strings.
  41    Their unit is an uint32_t (a 4-byte word).
  42
  43    All argument pairs (s, n) denote a Unicode string s[0..n-1] with exactly
  44    n units.
  45
  46    Functions returning a string result take a (resultbuf, lengthp) argument
  47    pair.  If resultbuf is not NULL and the result fits into *lengthp units,
  48    it is put in resultbuf, and resultbuf is returned.  Otherwise, a freshly
  49    allocated string is returned.  In both cases, *lengthp is set to the
  50    length (number of units) of the returned string.  In case of error,
  51    NULL is returned and errno is set.  */
  52
  53
  54 enum
  55 {
  56   UC_DECOMP_CANONICAL,/*            Canonical decomposition.                  */
  57   UC_DECOMP_FONT,    /*   <font>    A font variant (e.g. a blackletter form). */
  58   UC_DECOMP_NOBREAK, /* <noBreak>   A no-break version of a space or hyphen.  */
  59   UC_DECOMP_INITIAL, /* <initial>   An initial presentation form (Arabic).    */
  60   UC_DECOMP_MEDIAL,  /*  <medial>   A medial presentation form (Arabic).      */
  61   UC_DECOMP_FINAL,   /*  <final>    A final presentation form (Arabic).       */
  62   UC_DECOMP_ISOLATED,/* <isolated>  An isolated presentation form (Arabic).   */
  63   UC_DECOMP_CIRCLE,  /*  <circle>   An encircled form.                        */
  64   UC_DECOMP_SUPER,   /*  <super>    A superscript form.                       */
  65   UC_DECOMP_SUB,     /*   <sub>     A subscript form.                         */
  66   UC_DECOMP_VERTICAL,/* <vertical>  A vertical layout presentation form.      */
  67   UC_DECOMP_WIDE,    /*   <wide>    A wide (or zenkaku) compatibility character. */
  68   UC_DECOMP_NARROW,  /*  <narrow>   A narrow (or hankaku) compatibility character. */
  69   UC_DECOMP_SMALL,   /*  <small>    A small variant form (CNS compatibility). */
  70   UC_DECOMP_SQUARE,  /*  <square>   A CJK squared font variant.               */
  71   UC_DECOMP_FRACTION,/* <fraction>  A vulgar fraction form.                   */
  72   UC_DECOMP_COMPAT   /*  <compat>   Otherwise unspecified compatibility character. */
  73 };
  74
  75 /* Maximum size of decomposition of a single Unicode character.  */
  76 #define UC_DECOMPOSITION_MAX_LENGTH 32
  77
  78 /* Return the character decomposition mapping of a Unicode character.
  79    DECOMPOSITION must point to an array of at least UC_DECOMPOSITION_MAX_LENGTH
  80    ucs_t elements.
  81    When a decomposition exists, DECOMPOSITION[0..N-1] and *DECOMP_TAG are
  82    filled and N is returned.  Otherwise -1 is returned.  */
  83 extern int
  84        uc_decomposition (ucs4_t uc, int *decomp_tag, ucs4_t *decomposition);
  85
  86 /* Return the canonical character decomposition mapping of a Unicode character.
  87    DECOMPOSITION must point to an array of at least UC_DECOMPOSITION_MAX_LENGTH
  88    ucs_t elements.
  89    When a decomposition exists, DECOMPOSITION[0..N-1] is filled and N is
  90    returned.  Otherwise -1 is returned.  */
  91 extern int
  92        uc_canonical_decomposition (ucs4_t uc, ucs4_t *decomposition);
  93
  94
  95 /* Attempt to combine the Unicode characters uc1, uc2.
  96    uc1 is known to have canonical combining class 0.
  97    Return the combination of uc1 and uc2, if it exists.
  98    Return 0 otherwise.
  99    Not all decompositions can be recombined using this function.  See the
 100    Unicode file CompositionExclusions.txt for details.  */
 101 extern ucs4_t
 102        uc_composition (ucs4_t uc1, ucs4_t uc2)
 103        _UC_ATTRIBUTE_CONST;
 104
 105
 106 /* An object of type uninorm_t denotes a Unicode normalization form.  */
 107 struct unicode_normalization_form;
 108 typedef const struct unicode_normalization_form *uninorm_t;
 109
 110 /* UNINORM_NFD: Normalization form D: canonical decomposition.  */
 111 extern const struct unicode_normalization_form uninorm_nfd;
 112 #define UNINORM_NFD (&uninorm_nfd)
 113
 114 /* UNINORM_NFC: Normalization form C: canonical decomposition, then
 115    canonical composition.  */
 116 extern const struct unicode_normalization_form uninorm_nfc;
 117 #define UNINORM_NFC (&uninorm_nfc)
 118
 119 /* UNINORM_NFKD: Normalization form KD: compatibility decomposition.  */
 120 extern const struct unicode_normalization_form uninorm_nfkd;
 121 #define UNINORM_NFKD (&uninorm_nfkd)
 122
 123 /* UNINORM_NFKC: Normalization form KC: compatibility decomposition, then
 124    canonical composition.  */
 125 extern const struct unicode_normalization_form uninorm_nfkc;
 126 #define UNINORM_NFKC (&uninorm_nfkc)
 127
 128 /* Test whether a normalization form does compatibility decomposition.  */
 129 #define uninorm_is_compat_decomposing(nf) \
 130   ((* (const unsigned int *) (nf) >> 0) & 1)
 131
 132 /* Test whether a normalization form includes canonical composition.  */
 133 #define uninorm_is_composing(nf) \
 134   ((* (const unsigned int *) (nf) >> 1) & 1)
 135
 136 /* Return the decomposing variant of a normalization form.
 137    This maps NFC,NFD -> NFD and NFKC,NFKD -> NFKD.  */
 138 extern uninorm_t
 139        uninorm_decomposing_form (uninorm_t nf)
 140        _UC_ATTRIBUTE_PURE;
 141
 142
 143 /* Return the specified normalization form of a string.  */
 144 extern uint8_t *
 145        u8_normalize (uninorm_t nf, const uint8_t *s, size_t n,
 146                      uint8_t *_UC_RESTRICT resultbuf, size_t *lengthp);
 147 extern uint16_t *
 148        u16_normalize (uninorm_t nf, const uint16_t *s, size_t n,
 149                       uint16_t *_UC_RESTRICT resultbuf, size_t *lengthp);
 150 extern uint32_t *
 151        u32_normalize (uninorm_t nf, const uint32_t *s, size_t n,
 152                       uint32_t *_UC_RESTRICT resultbuf, size_t *lengthp);
 153
 154
 155 /* Compare S1 and S2, ignoring differences in normalization.
 156    NF must be either UNINORM_NFD or UNINORM_NFKD.
 157    If successful, set *RESULTP to -1 if S1 < S2, 0 if S1 = S2, 1 if S1 > S2, and
 158    return 0.  Upon failure, return -1 with errno set.  */
 159 extern int
 160        u8_normcmp (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2,
 161                    uninorm_t nf, int *resultp);
 162 extern int
 163        u16_normcmp (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2,
 164                     uninorm_t nf, int *resultp);
 165 extern int
 166        u32_normcmp (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2,
 167                     uninorm_t nf, int *resultp);
 168
 169
 170 /* Converts the string S of length N to a NUL-terminated byte sequence, in such
 171    a way that comparing uN_normxfrm (S1) and uN_normxfrm (S2) with uN_cmp2() is
 172    equivalent to comparing S1 and S2 with uN_normcoll().
 173    NF must be either UNINORM_NFC or UNINORM_NFKC.  */
 174 extern char *
 175        u8_normxfrm (const uint8_t *s, size_t n, uninorm_t nf,
 176                     char *resultbuf, size_t *lengthp);
 177 extern char *
 178        u16_normxfrm (const uint16_t *s, size_t n, uninorm_t nf,
 179                      char *resultbuf, size_t *lengthp);
 180 extern char *
 181        u32_normxfrm (const uint32_t *s, size_t n, uninorm_t nf,
 182                      char *resultbuf, size_t *lengthp);
 183
 184
 185 /* Compare S1 and S2, ignoring differences in normalization, using the
 186    collation rules of the current locale.
 187    NF must be either UNINORM_NFC or UNINORM_NFKC.
 188    If successful, set *RESULTP to -1 if S1 < S2, 0 if S1 = S2, 1 if S1 > S2, and
 189    return 0.  Upon failure, return -1 with errno set.  */
 190 extern int
 191        u8_normcoll (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2,
 192                     uninorm_t nf, int *resultp);
 193 extern int
 194        u16_normcoll (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2,
 195                      uninorm_t nf, int *resultp);
 196 extern int
 197        u32_normcoll (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2,
 198                      uninorm_t nf, int *resultp);
 199
 200
 201 /* Normalization of a stream of Unicode characters.
 202
 203    A "stream of Unicode characters" is essentially a function that accepts an
 204    ucs4_t argument repeatedly, optionally combined with a function that
 205    "flushes" the stream.  */
 206
 207 /* Data type of a stream of Unicode characters that normalizes its input
 208    according to a given normalization form and passes the normalized character
 209    sequence to the encapsulated stream of Unicode characters.  */
 210 struct uninorm_filter;
 211
 212 /* Create and return a normalization filter for Unicode characters.
 213    The pair (stream_func, stream_data) is the encapsulated stream.
 214    stream_func (stream_data, uc) receives the Unicode character uc
 215    and returns 0 if successful, or -1 with errno set upon failure.
 216    Return the new filter, or NULL with errno set upon failure.  */
 217 extern struct uninorm_filter *
 218        uninorm_filter_create (uninorm_t nf,
 219                               int (*stream_func) (void *stream_data, ucs4_t uc),
 220                               void *stream_data);
 221
 222 /* Stuff a Unicode character into a normalizing filter.
 223    Return 0 if successful, or -1 with errno set upon failure.  */
 224 extern int
 225        uninorm_filter_write (struct uninorm_filter *filter, ucs4_t uc);
 226
 227 /* Bring data buffered in the filter to its destination, the encapsulated
 228    stream.
 229    Return 0 if successful, or -1 with errno set upon failure.
 230    Note! If after calling this function, additional characters are written
 231    into the filter, the resulting character sequence in the encapsulated stream
 232    will not necessarily be normalized.  */
 233 extern int
 234        uninorm_filter_flush (struct uninorm_filter *filter);
 235
 236 /* Bring data buffered in the filter to its destination, the encapsulated
 237    stream, then close and free the filter.
 238    Return 0 if successful, or -1 with errno set upon failure.  */
 239 extern int
 240        uninorm_filter_free (struct uninorm_filter *filter);
 241
 242
 243 #ifdef __cplusplus
 244 }
 245 #endif
 246
 247
 248 #endif /* _UNINORM_H */