lib/ucs4swapped.h

   1 /*
   2  * Copyright (C) 1999-2000, 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 Lesser General Public
   7  * License as published by the Free Software Foundation; either version 2.1
   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  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser 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  * UCS-4-SWAPPED = UCS-4-INTERNAL with inverted endianness
  22  */
  23
  24 static int
  25 ucs4swapped_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
  26 {
  27   /* This function assumes that 'unsigned int' has exactly 32 bits. */
  28   if (sizeof(unsigned int) != 4) abort();
  29
  30   if (n >= 4) {
  31     unsigned int x = *(const unsigned int *)s;
  32     x = (x >> 24) | ((x >> 8) & 0xff00) | ((x & 0xff00) << 8) | (x << 24);
  33     *pwc = x;
  34     return 4;
  35   }
  36   return RET_TOOFEW(0);
  37 }
  38
  39 static int
  40 ucs4swapped_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, size_t n)
  41 {
  42   /* This function assumes that 'unsigned int' has exactly 32 bits. */
  43   if (sizeof(unsigned int) != 4) abort();
  44
  45   if (n >= 4) {
  46     unsigned int x = wc;
  47     x = (x >> 24) | ((x >> 8) & 0xff00) | ((x & 0xff00) << 8) | (x << 24);
  48     *(unsigned int *)r = x;
  49     return 4;
  50   } else
  51     return RET_TOOSMALL;
  52 }