utf8.c

   1 /*
   2  * utf-8.c
   3  * Copyright (C) 2001,2002 A.J. van Os; Released under GPL
   4  *
   5  *====================================================================
   6  * This part of the software is based on:
   7  * An implementation of wcwidth() as defined in
   8  * "The Single UNIX Specification, Version 2, The Open Group, 1997"
   9  * <http://www.UNIX-systems.org/online.html>
  10  * Markus Kuhn -- 2001-01-12 -- public domain
  11  *====================================================================
  12  * The credit should go to him, but all the bugs are mine.
  13  */
  14
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include "antiword.h"
  18
  19 struct interval {
  20         USHORT  first;
  21         USHORT  last;
  22 };
  23 /* Sorted list of non-overlapping intervals of non-spacing characters */
  24 static const struct interval combining[] = {
  25         { 0x0300, 0x034E }, { 0x0360, 0x0362 }, { 0x0483, 0x0486 },
  26         { 0x0488, 0x0489 }, { 0x0591, 0x05A1 }, { 0x05A3, 0x05B9 },
  27         { 0x05BB, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
  28         { 0x05C4, 0x05C4 }, { 0x064B, 0x0655 }, { 0x0670, 0x0670 },
  29         { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
  30         { 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
  31         { 0x07A6, 0x07B0 }, { 0x0901, 0x0902 }, { 0x093C, 0x093C },
  32         { 0x0941, 0x0948 }, { 0x094D, 0x094D }, { 0x0951, 0x0954 },
  33         { 0x0962, 0x0963 }, { 0x0981, 0x0981 }, { 0x09BC, 0x09BC },
  34         { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 },
  35         { 0x0A02, 0x0A02 }, { 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 },
  36         { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D }, { 0x0A70, 0x0A71 },
  37         { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC }, { 0x0AC1, 0x0AC5 },
  38         { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD }, { 0x0B01, 0x0B01 },
  39         { 0x0B3C, 0x0B3C }, { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 },
  40         { 0x0B4D, 0x0B4D }, { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 },
  41         { 0x0BC0, 0x0BC0 }, { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 },
  42         { 0x0C46, 0x0C48 }, { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 },
  43         { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
  44         { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D }, { 0x0DCA, 0x0DCA },
  45         { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 }, { 0x0E31, 0x0E31 },
  46         { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E }, { 0x0EB1, 0x0EB1 },
  47         { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC }, { 0x0EC8, 0x0ECD },
  48         { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 }, { 0x0F37, 0x0F37 },
  49         { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E }, { 0x0F80, 0x0F84 },
  50         { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 }, { 0x0F99, 0x0FBC },
  51         { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 }, { 0x1032, 0x1032 },
  52         { 0x1036, 0x1037 }, { 0x1039, 0x1039 }, { 0x1058, 0x1059 },
  53         { 0x1160, 0x11FF }, { 0x17B7, 0x17BD }, { 0x17C6, 0x17C6 },
  54         { 0x17C9, 0x17D3 }, { 0x180B, 0x180E }, { 0x18A9, 0x18A9 },
  55         { 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x206A, 0x206F },
  56         { 0x20D0, 0x20E3 }, { 0x302A, 0x302F }, { 0x3099, 0x309A },
  57         { 0xFB1E, 0xFB1E }, { 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF },
  58         { 0xFFF9, 0xFFFB }
  59 };
  60
  61 /* Auxiliary function for binary search in interval table */
  62 static BOOL
  63 bIsZeroWidthChar(ULONG ucs)
  64 {
  65         int low = 0;
  66         int high = elementsof(combining) - 1;
  67         int mid;
  68
  69         if (ucs < (ULONG)combining[low].first ||
  70             ucs > (ULONG)combining[high].last) {
  71                 return FALSE;
  72         }
  73
  74         while (high >= low) {
  75                 mid = (low + high) / 2;
  76                 if (ucs > (ULONG)combining[mid].last) {
  77                         low = mid + 1;
  78                 } else if (ucs < (ULONG)combining[mid].first) {
  79                         high = mid - 1;
  80                 } else {
  81                         return TRUE;
  82                 }
  83         }
  84         return FALSE;
  85 } /* end of bIsZeroWidthChar */
  86
  87 /* The following functions define the column width of an ISO 10646
  88  * character as follows:
  89  *
  90  *    - The null character (U+0000) has a column width of 0.
  91  *
  92  *    - Other C0/C1 control characters and DEL will lead to a return
  93  *      value of -1.
  94  *
  95  *    - Non-spacing and enclosing combining characters (general
  96  *      category code Mn or Me in the Unicode database) have a
  97  *      column width of 0.
  98  *
  99  *    - Other format characters (general category code Cf in the Unicode
 100  *      database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
 101  *
 102  *    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
 103  *      have a column width of 0.
 104  *
 105  *    - Spacing characters in the East Asian Wide (W) or East Asian
 106  *      FullWidth (F) category as defined in Unicode Technical
 107  *      Report #11 have a column width of 2.
 108  *
 109  *    - All remaining characters (including all printable
 110  *      ISO 8859-1 and WGL4 characters, Unicode control characters,
 111  *      etc.) have a column width of 1.
 112  *
 113  * This implementation assumes that all characters are encoded
 114  * in ISO 10646.
 115  *
 116  * This function is not named wcwidth() to prevent name clashes
 117  */
 118 static int
 119 iWcWidth(ULONG ucs)
 120 {
 121         /* Test for 8-bit control characters */
 122         if (ucs == 0) {
 123                 return 0;
 124         }
 125         if (ucs < 0x20 || (ucs >= 0x7f && ucs < 0xa0)) {
 126                 NO_DBG_HEX(ucs);
 127                 return -1;
 128         }
 129
 130         /* Binary search in table of non-spacing characters */
 131         if (bIsZeroWidthChar(ucs)) {
 132                 return 0;
 133         }
 134
 135         /* Ucs is not a combining or C0/C1 control character */
 136
 137         return 1 +
 138         (ucs >= 0x1100 &&
 139          (ucs <= 0x115f ||                    /* Hangul Jamo init. consonants */
 140           (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a &&
 141            ucs != 0x303f) ||                  /* CJK ... Yi */
 142           (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */
 143           (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */
 144           (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
 145           (ucs >= 0xff00 && ucs <= 0xff5f) || /* Fullwidth Forms */
 146           (ucs >= 0xffe0 && ucs <= 0xffe6) ||
 147           (ucs >= 0x20000 && ucs <= 0x2ffff)));
 148 } /* end of iWcWidth */
 149
 150 #if 0
 151 int
 152 wcswidth(const ULONG *pwcs, size_t n)
 153 {
 154         int w, width = 0;
 155
 156         for (;*pwcs && n-- > 0; pwcs++) {
 157         w = iWcWidth(*pwcs);
 158         if (w < 0) {
 159         return -1;
 160         }
 161         width += w;
 162         }
 163         return width;
 164 } /* end of wcswidth */
 165 #endif
 166
 167 static ULONG
 168 utf8_to_ucs(const char *p, int *utflen)
 169 {
 170         ULONG   wc = (ULONG)(UCHAR)p[0];
 171         int charlen;
 172         int j;
 173
 174         if (wc < 0x80) {
 175                 *utflen = 1;
 176                 return wc;
 177         }
 178
 179         if (wc < 0xe0){
 180                 charlen = 2;
 181                 wc &= 0x1f;
 182         } else if (wc < 0xf0){
 183                 charlen = 3;
 184                 wc &= 0x0f;
 185         } else if (wc < 0xf8){
 186                 charlen = 4;
 187                 wc &= 0x07;
 188         } else if (wc < 0xfc){
 189                 charlen = 5;
 190                 wc &= 0x03;
 191         } else {
 192                 charlen = 6;
 193                 wc &= 0x01;
 194         }
 195         for (j = 1; j < charlen; j++) {
 196                 wc <<= 6;
 197                 wc |= (UCHAR)p[j] & 0x3f;
 198         }
 199         *utflen = charlen;
 200         return wc;
 201 } /* end of utf8_to_ucs */
 202
 203 long
 204 utf8_strwidth(const char *p, int numchars)
 205 {
 206         const char      *maxp;
 207         ULONG   ucs;
 208         long    width, totwidth;
 209         int     utflen;
 210
 211         totwidth = 0;
 212         maxp = p + numchars;
 213
 214         while (*p != '\0' && p < maxp) {
 215                 ucs = utf8_to_ucs(p, &utflen);
 216                 width = iWcWidth(ucs);
 217                 if (width > 0) {
 218                         totwidth += width;
 219                 }
 220                 p += utflen;
 221         }
 222         return totwidth;
 223 } /* end of utf8_strwidth */
 224
 225 /*
 226  * Original version:
 227  * Copyright (C) 1999  Bruno Haible
 228  */
 229 BOOL
 230 is_locale_utf8(void)
 231 {
 232         const char      *locale, *cp, *encoding;
 233
 234         /*
 235          * Determine the current locale the same way as setlocale() does,
 236          * according to POSIX.
 237          */
 238         locale = getenv("LC_ALL");
 239         if (locale == NULL || locale[0] == '\0') {
 240                 locale = getenv("LC_CTYPE");
 241                 if (locale == NULL || locale[0] == '\0') {
 242                         locale = getenv("LANG");
 243                 }
 244         }
 245
 246         if (locale == NULL || locale[0] == '\0') {
 247                 return FALSE;
 248         }
 249
 250         /* The most general syntax of a locale (not all optional parts
 251          * recognized by all systems) is
 252          * language[_territory][.codeset][@modifier][+special][,[sponsor][_revision]]
 253          * To retrieve the codeset, search the first dot. Stop searching when
 254          * a '@' or '+' or ',' is encountered.
 255          */
 256         for (cp = locale;
 257              *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ',';
 258              cp++) {
 259                 if (*cp != '.') {
 260                         continue;
 261                 }
 262                 encoding = cp + 1;
 263                 for (cp = encoding;
 264                      *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ',';
 265                      cp++)
 266                         ;       /* EMPTY */
 267                 /*
 268                  * The encoding is now contained in the part from encoding to
 269                  * cp. Check it for "UTF-8", which is the only official IANA
 270                  * name of UTF-8. Also check for the lowercase-no-dashes
 271                  * version, which is what some SystemV systems use.
 272                  */
 273                 if ((cp - encoding == 5 && STRNEQ(encoding, "UTF-8", 5)) ||
 274                     (cp - encoding == 4 && STRNEQ(encoding, "utf8", 4))) {
 275                         return TRUE;
 276                 }
 277                 return FALSE;
 278         }
 279         return FALSE;
 280 } /* end of is_locale_utf8 */