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libiconv 1.16

    1: /*
    2:  * Copyright (C) 1999-2001, 2007, 2016 Free Software Foundation, Inc.
    3:  * This file is part of the GNU LIBICONV Library.
    4:  *
    5:  * The GNU LIBICONV Library is free software; you can redistribute it
    6:  * and/or modify it under the terms of the GNU Library General Public
    7:  * License as published by the Free Software Foundation; either version 2
    8:  * of the License, or (at your option) any later version.
    9:  *
   10:  * The GNU LIBICONV Library is distributed in the hope that it will be
   11:  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   13:  * Library General Public License for more details.
   14:  *
   15:  * You should have received a copy of the GNU Library General Public
   16:  * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
   17:  * If not, see <https://www.gnu.org/licenses/>.
   18:  */
   19: 
   20: /*
   21:  * JOHAB
   22:  */
   23: 
   24: /*
   25:    Conversion between JOHAB codes (s1,s2) and KSX1001 codes (c1,c2):
   26:    Example. (s1,s2) = 0xD931, (c1,c2) = 0x2121.
   27:             (s1,s2) = 0xDEF1, (c1,c2) = 0x2C71.
   28:             (s1,s2) = 0xE031, (c1,c2) = 0x4A21.
   29:             (s1,s2) = 0xF9FE, (c1,c2) = 0x7D7E.
   30:    0xD9 <= s1 <= 0xDE || 0xE0 <= s1 <= 0xF9,
   31:    0x31 <= s2 <= 0x7E || 0x91 <= s2 <= 0xFE,
   32:    0x21 <= c1 <= 0x2C || 0x4A <= c1 <= 0x7D,
   33:    0x21 <= c2 <= 0x7E.
   34:    Invariant:
   35:      94*(s1 < 0xE0 ? 2*s1-0x1B2 : 2*s1-0x197) + (s2 < 0x91 ? s2-0x31 : s2-0x43)
   36:      = 94*(c1-0x21)+(c2-0x21)
   37:    Conversion (s1,s2) -> (c1,c2):
   38:      t1 := (s1 < 0xE0 ? 2*s1-0x1B2 : 2*s1-0x197)
   39:      t2 := (s2 < 0x91 ? s2-0x31 : s2-0x43)
   40:      c1 := t1 + (t2 < 0x5E ? 0 : 1) + 0x21
   41:      c2 := (t2 < 0x5E ? t2 : t2-0x5E) + 0x21
   42:    Conversion (c1,c2) -> (s1,s2):
   43:      t := (c1 < 0x4A ? (c1-0x21+0x1B2) : (c1-0x21+0x197))
   44:      s1 := t >> 1
   45:      t2 := (t & 1) * 0x5E + (c2 - 0x21)
   46:      s2 := (t2 < 0x4E ? t2+0x31 : t2+0x43)
   47:  */
   48: 
   49: static int
   50: johab_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
   51: {
   52:   unsigned char c = *s;
   53:   if (c < 0x80) {
   54:     if (c == 0x5c)
   55:       *pwc = (ucs4_t) 0x20a9;
   56:     else
   57:       *pwc = (ucs4_t) c;
   58:     return 1;
   59:   } else if (c < 0xd8) {
   60:     return johab_hangul_mbtowc(conv,pwc,s,n);
   61:   } else {
   62:     unsigned char s1, s2;
   63:     s1 = c;
   64:     if ((s1 >= 0xd9 && s1 <= 0xde) || (s1 >= 0xe0 && s1 <= 0xf9)) {
   65:       if (n < 2)
   66:         return RET_TOOFEW(0);
   67:       s2 = s[1];
   68:       if ((s2 >= 0x31 && s2 <= 0x7e) || (s2 >= 0x91 && s2 <= 0xfe)) {
   69:         /* In KSC 5601, now KS X 1001, the region s1 = 0xDA, 0xA1 <= s2 <= 0xD3
   70:            contains the 51 Jamo (Hangul letters). But in the Johab encoding,
   71:            they have been moved to the Hangul section, see
   72:            johab_hangul_page31. */
   73:         if (!(s1 == 0xda && (s2 >= 0xa1 && s2 <= 0xd3))) {
   74:           unsigned char t1 = (s1 < 0xe0 ? 2*(s1-0xd9) : 2*s1-0x197);
   75:           unsigned char t2 = (s2 < 0x91 ? s2-0x31 : s2-0x43);
   76:           unsigned char buf[2];
   77:           buf[0] = t1 + (t2 < 0x5e ? 0 : 1) + 0x21;
   78:           buf[1] = (t2 < 0x5e ? t2 : t2-0x5e) + 0x21;
   79:           return ksc5601_mbtowc(conv,pwc,buf,2);
   80:         }
   81:       }
   82:     }
   83:     return RET_ILSEQ;
   84:   }
   85: }
   86: 
   87: static int
   88: johab_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
   89: {
   90:   unsigned char buf[2];
   91:   int ret;
   92: 
   93:   /* Try ASCII variation. */
   94:   if (wc < 0x0080 && wc != 0x005c) {
   95:     *r = wc;
   96:     return 1;
   97:   }
   98:   if (wc == 0x20a9) {
   99:     *r = 0x5c;
  100:     return 1;
  101:   }
  102: 
  103:   /* Try JOHAB Hangul table before KSC5601 table, because the KSC5601 table
  104:      contains some (2350 out of 11172) Hangul syllables (rows 0x30XX..0x48XX),
  105:      and we want the search to return the JOHAB Hangul table entry. */
  106: 
  107:   /* Try JOHAB Hangul. */
  108:   ret = johab_hangul_wctomb(conv,buf,wc,2);
  109:   if (ret != RET_ILUNI) {
  110:     if (ret != 2) abort();
  111:     if (n < 2)
  112:       return RET_TOOSMALL;
  113:     r[0] = buf[0];
  114:     r[1] = buf[1];
  115:     return 2;
  116:   }
  117: 
  118:   /* Try KSC5601, now KS X 1001. */
  119:   ret = ksc5601_wctomb(conv,buf,wc,2);
  120:   if (ret != RET_ILUNI) {
  121:     unsigned char c1, c2;
  122:     if (ret != 2) abort();
  123:     if (n < 2)
  124:       return RET_TOOSMALL;
  125:     c1 = buf[0];
  126:     c2 = buf[1];
  127:     if (((c1 >= 0x21 && c1 <= 0x2c) || (c1 >= 0x4a && c1 <= 0x7d))
  128:         && (c2 >= 0x21 && c2 <= 0x7e)) {
  129:       unsigned int t = (c1 < 0x4A ? (c1-0x21+0x1B2) : (c1-0x21+0x197));
  130:       unsigned char t2 = ((t & 1) ? 0x5e : 0) + (c2 - 0x21);
  131:       r[0] = t >> 1;
  132:       r[1] = (t2 < 0x4e ? t2+0x31 : t2+0x43);
  133:       return 2;
  134:     }
  135:   }
  136: 
  137:   return RET_ILUNI;
  138: }