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libiconv 1.16

    1: /*
    2:  * Copyright (C) 1999-2001, 2008, 2011, 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:  * UTF-32
   22:  */
   23: 
   24: /* Specification: Unicode 3.1 Standard Annex #19 */
   25: 
   26: /* Here we accept FFFE0000/0000FEFF marks as endianness indicators
   27:    everywhere in the stream, not just at the beginning. (This is contrary
   28:    to what #19 D36c specifies, but it allows concatenation of byte
   29:    sequences to work flawlessly, while disagreeing with #19 behaviour
   30:    only for strings containing U+FEFF characters, which is quite rare.)
   31:    The default is big-endian. */
   32: /* The state is 0 if big-endian, 1 if little-endian. */
   33: static int
   34: utf32_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
   35: {
   36:   state_t state = conv->istate;
   37:   int count = 0;
   38:   for (; n >= 4 && count <= RET_COUNT_MAX && count <= INT_MAX-4;) {
   39:     ucs4_t wc = (state
   40:                   ? s[0] + (s[1] << 8) + (s[2] << 16) + (s[3] << 24)
   41:                   : (s[0] << 24) + (s[1] << 16) + (s[2] << 8) + s[3]);
   42:     if (wc == 0x0000feff) {
   43:     } else if (wc == 0xfffe0000u) {
   44:       state ^= 1;
   45:     } else {
   46:       if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000)) {
   47:         *pwc = wc;
   48:         conv->istate = state;
   49:         return count+4;
   50:       } else {
   51:         conv->istate = state;
   52:         return RET_SHIFT_ILSEQ(count);
   53:       }
   54:     }
   55:     s += 4; n -= 4; count += 4;
   56:   }
   57:   conv->istate = state;
   58:   return RET_TOOFEW(count);
   59: }
   60: 
   61: /* We output UTF-32 in big-endian order, with byte-order mark. */
   62: /* The state is 0 at the beginning, 1 after the BOM has been written. */
   63: static int
   64: utf32_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
   65: {
   66:   if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000)) {
   67:     int count = 0;
   68:     if (!conv->ostate) {
   69:       if (n >= 4) {
   70:         r[0] = 0x00;
   71:         r[1] = 0x00;
   72:         r[2] = 0xFE;
   73:         r[3] = 0xFF;
   74:         r += 4; n -= 4; count += 4;
   75:       } else
   76:         return RET_TOOSMALL;
   77:     }
   78:     if (wc < 0x110000) {
   79:       if (n >= 4) {
   80:         r[0] = 0;
   81:         r[1] = (unsigned char) (wc >> 16);
   82:         r[2] = (unsigned char) (wc >> 8);
   83:         r[3] = (unsigned char) wc;
   84:         conv->ostate = 1;
   85:         return count+4;
   86:       } else
   87:         return RET_TOOSMALL;
   88:     }
   89:   }
   90:   return RET_ILUNI;
   91: }