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libiconv

    1: /*
    2:  * Copyright (C) 1999-2002 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, write to the Free Software Foundation, Inc., 51 Franklin Street,
   18:  * Fifth Floor, Boston, MA 02110-1301, USA.
   19:  */
   20: 
   21: /*
   22:  * SHIFT_JIS
   23:  */
   24: 
   25: /*
   26:    Conversion between SJIS codes (s1,s2) and JISX0208 codes (c1,c2):
   27:    Example. (s1,s2) = 0x8140, (c1,c2) = 0x2121.
   28:    0x81 <= s1 <= 0x9F || 0xE0 <= s1 <= 0xEA,
   29:    0x40 <= s2 <= 0x7E || 0x80 <= s2 <= 0xFC,
   30:    0x21 <= c1 <= 0x74, 0x21 <= c2 <= 0x7E.
   31:    Invariant:
   32:      94*2*(s1 < 0xE0 ? s1-0x81 : s1-0xC1) + (s2 < 0x80 ? s2-0x40 : s2-0x41)
   33:      = 94*(c1-0x21)+(c2-0x21)
   34:    Conversion (s1,s2) -> (c1,c2):
   35:      t1 := (s1 < 0xE0 ? s1-0x81 : s1-0xC1)
   36:      t2 := (s2 < 0x80 ? s2-0x40 : s2-0x41)
   37:      c1 := 2*t1 + (t2 < 0x5E ? 0 : 1) + 0x21
   38:      c2 := (t2 < 0x5E ? t2 : t2-0x5E) + 0x21
   39:    Conversion (c1,c2) -> (s1,s2):
   40:      t1 := (c1 - 0x21) >> 1
   41:      t2 := ((c1 - 0x21) & 1) * 0x5E + (c2 - 0x21)
   42:      s1 := (t1 < 0x1F ? t1+0x81 : t1+0xC1)
   43:      s2 := (t2 < 0x3F ? t2+0x40 : t2+0x41)
   44:  */
   45: 
   46: static int
   47: sjis_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
   48: {
   49:   unsigned char c = *s;
   50:   if (c < 0x80 || (c >= 0xa1 && c <= 0xdf))
   51:     return jisx0201_mbtowc(conv,pwc,s,n);
   52:   else {
   53:     unsigned char s1, s2;
   54:     s1 = c;
   55:     if ((s1 >= 0x81 && s1 <= 0x9f) || (s1 >= 0xe0 && s1 <= 0xea)) {
   56:       if (n < 2)
   57:         return RET_TOOFEW(0);
   58:       s2 = s[1];
   59:       if ((s2 >= 0x40 && s2 <= 0x7e) || (s2 >= 0x80 && s2 <= 0xfc)) {
   60:         unsigned char t1 = (s1 < 0xe0 ? s1-0x81 : s1-0xc1);
   61:         unsigned char t2 = (s2 < 0x80 ? s2-0x40 : s2-0x41);
   62:         unsigned char buf[2];
   63:         buf[0] = 2*t1 + (t2 < 0x5e ? 0 : 1) + 0x21;
   64:         buf[1] = (t2 < 0x5e ? t2 : t2-0x5e) + 0x21;
   65:         return jisx0208_mbtowc(conv,pwc,buf,2);
   66:       }
   67:     } else if (s1 >= 0xf0 && s1 <= 0xf9) {
   68:       /* User-defined range. See
   69:        * Ken Lunde's "CJKV Information Processing", table 4-66, p. 206. */
   70:       if (n < 2)
   71:         return RET_TOOFEW(0);
   72:       s2 = s[1];
   73:       if ((s2 >= 0x40 && s2 <= 0x7e) || (s2 >= 0x80 && s2 <= 0xfc)) {
   74:         *pwc = 0xe000 + 188*(s1 - 0xf0) + (s2 < 0x80 ? s2-0x40 : s2-0x41);
   75:         return 2;
   76:       }
   77:     }
   78:     return RET_ILSEQ;
   79:   }
   80: }
   81: 
   82: static int
   83: sjis_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
   84: {
   85:   unsigned char buf[2];
   86:   int ret;
   87: 
   88:   /* Try JIS X 0201-1976. */
   89:   ret = jisx0201_wctomb(conv,buf,wc,1);
   90:   if (ret != RET_ILUNI) {
   91:     unsigned char c;
   92:     if (ret != 1) abort();
   93:     c = buf[0];
   94:     if (c < 0x80 || (c >= 0xa1 && c <= 0xdf)) {
   95:       r[0] = c;
   96:       return 1;
   97:     }
   98:   }
   99: 
  100:   /* Try JIS X 0208-1990. */
  101:   ret = jisx0208_wctomb(conv,buf,wc,2);
  102:   if (ret != RET_ILUNI) {
  103:     unsigned char c1, c2;
  104:     if (ret != 2) abort();
  105:     if (n < 2)
  106:       return RET_TOOSMALL;
  107:     c1 = buf[0];
  108:     c2 = buf[1];
  109:     if ((c1 >= 0x21 && c1 <= 0x74) && (c2 >= 0x21 && c2 <= 0x7e)) {
  110:       unsigned char t1 = (c1 - 0x21) >> 1;
  111:       unsigned char t2 = (((c1 - 0x21) & 1) ? 0x5e : 0) + (c2 - 0x21);
  112:       r[0] = (t1 < 0x1f ? t1+0x81 : t1+0xc1);
  113:       r[1] = (t2 < 0x3f ? t2+0x40 : t2+0x41);
  114:       return 2;
  115:     }
  116:   }
  117: 
  118:   /* User-defined range. See
  119:    * Ken Lunde's "CJKV Information Processing", table 4-66, p. 206. */
  120:   if (wc >= 0xe000 && wc < 0xe758) {
  121:     unsigned char c1, c2;
  122:     if (n < 2)
  123:       return RET_TOOSMALL;
  124:     c1 = (unsigned int) (wc - 0xe000) / 188;
  125:     c2 = (unsigned int) (wc - 0xe000) % 188;
  126:     r[0] = c1+0xf0;
  127:     r[1] = (c2 < 0x3f ? c2+0x40 : c2+0x41);
  128:     return 2;
  129:   }
  130: 
  131:   return RET_ILUNI;
  132: }