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libiconv

    1: /*
    2:  * Copyright (C) 1999-2001, 2004 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:  * UTF-8
   23:  */
   24: 
   25: /* Specification: RFC 3629 */
   26: 
   27: static int
   28: utf8_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
   29: {
   30:   unsigned char c = s[0];
   31: 
   32:   if (c < 0x80) {
   33:     *pwc = c;
   34:     return 1;
   35:   } else if (c < 0xc2) {
   36:     return RET_ILSEQ;
   37:   } else if (c < 0xe0) {
   38:     if (n < 2)
   39:       return RET_TOOFEW(0);
   40:     if (!((s[1] ^ 0x80) < 0x40))
   41:       return RET_ILSEQ;
   42:     *pwc = ((ucs4_t) (c & 0x1f) << 6)
   43:            | (ucs4_t) (s[1] ^ 0x80);
   44:     return 2;
   45:   } else if (c < 0xf0) {
   46:     if (n < 3)
   47:       return RET_TOOFEW(0);
   48:     if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
   49:           && (c >= 0xe1 || s[1] >= 0xa0)))
   50:       return RET_ILSEQ;
   51:     *pwc = ((ucs4_t) (c & 0x0f) << 12)
   52:            | ((ucs4_t) (s[1] ^ 0x80) << 6)
   53:            | (ucs4_t) (s[2] ^ 0x80);
   54:     return 3;
   55:   } else if (c < 0xf8 && sizeof(ucs4_t)*8 >= 32) {
   56:     if (n < 4)
   57:       return RET_TOOFEW(0);
   58:     if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
   59:           && (s[3] ^ 0x80) < 0x40
   60:           && (c >= 0xf1 || s[1] >= 0x90)))
   61:       return RET_ILSEQ;
   62:     *pwc = ((ucs4_t) (c & 0x07) << 18)
   63:            | ((ucs4_t) (s[1] ^ 0x80) << 12)
   64:            | ((ucs4_t) (s[2] ^ 0x80) << 6)
   65:            | (ucs4_t) (s[3] ^ 0x80);
   66:     return 4;
   67:   } else if (c < 0xfc && sizeof(ucs4_t)*8 >= 32) {
   68:     if (n < 5)
   69:       return RET_TOOFEW(0);
   70:     if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
   71:           && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
   72:           && (c >= 0xf9 || s[1] >= 0x88)))
   73:       return RET_ILSEQ;
   74:     *pwc = ((ucs4_t) (c & 0x03) << 24)
   75:            | ((ucs4_t) (s[1] ^ 0x80) << 18)
   76:            | ((ucs4_t) (s[2] ^ 0x80) << 12)
   77:            | ((ucs4_t) (s[3] ^ 0x80) << 6)
   78:            | (ucs4_t) (s[4] ^ 0x80);
   79:     return 5;
   80:   } else if (c < 0xfe && sizeof(ucs4_t)*8 >= 32) {
   81:     if (n < 6)
   82:       return RET_TOOFEW(0);
   83:     if (!((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
   84:           && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
   85:           && (s[5] ^ 0x80) < 0x40
   86:           && (c >= 0xfd || s[1] >= 0x84)))
   87:       return RET_ILSEQ;
   88:     *pwc = ((ucs4_t) (c & 0x01) << 30)
   89:            | ((ucs4_t) (s[1] ^ 0x80) << 24)
   90:            | ((ucs4_t) (s[2] ^ 0x80) << 18)
   91:            | ((ucs4_t) (s[3] ^ 0x80) << 12)
   92:            | ((ucs4_t) (s[4] ^ 0x80) << 6)
   93:            | (ucs4_t) (s[5] ^ 0x80);
   94:     return 6;
   95:   } else
   96:     return RET_ILSEQ;
   97: }
   98: 
   99: static int
  100: utf8_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n) /* n == 0 is acceptable */
  101: {
  102:   int count;
  103:   if (wc < 0x80)
  104:     count = 1;
  105:   else if (wc < 0x800)
  106:     count = 2;
  107:   else if (wc < 0x10000)
  108:     count = 3;
  109:   else if (wc < 0x200000)
  110:     count = 4;
  111:   else if (wc < 0x4000000)
  112:     count = 5;
  113:   else if (wc <= 0x7fffffff)
  114:     count = 6;
  115:   else
  116:     return RET_ILUNI;
  117:   if (n < count)
  118:     return RET_TOOSMALL;
  119:   switch (count) { /* note: code falls through cases! */
  120:     case 6: r[5] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x4000000;
  121:     case 5: r[4] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x200000;
  122:     case 4: r[3] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x10000;
  123:     case 3: r[2] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0x800;
  124:     case 2: r[1] = 0x80 | (wc & 0x3f); wc = wc >> 6; wc |= 0xc0;
  125:     case 1: r[0] = wc;
  126:   }
  127:   return count;
  128: }