c16rtomb.cpp revision 7a7f9952c12b216fbf91fc4cdbb97045e8861115 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <errno.h>
30#include <uchar.h>
31#include <wchar.h>
32
33#include "private/bionic_mbstate.h"
34
35static inline constexpr bool is_high_surrogate(char16_t c16) {
36  return c16 >= 0xd800 && c16 < 0xdc00;
37}
38
39static inline constexpr bool is_low_surrogate(char16_t c16) {
40  return c16 >= 0xdc00 && c16 < 0xe000;
41}
42
43size_t c16rtomb(char* s, char16_t c16, mbstate_t* ps) {
44  static mbstate_t __private_state;
45  mbstate_t* state = (ps == NULL) ? &__private_state : ps;
46  if (mbsinit(state)) {
47    if (is_high_surrogate(c16)) {
48      char32_t c32 = (c16 & ~0xd800) << 10;
49      mbstate_set_byte(state, 3, (c32 & 0xff0000) >> 16);
50      mbstate_set_byte(state, 2, (c32 & 0x00ff00) >> 8);
51      return 0;
52    } else if (is_low_surrogate(c16)) {
53      return reset_and_return_illegal(EINVAL, state);
54    } else {
55      return c32rtomb(s, static_cast<char32_t>(c16), state);
56    }
57  } else {
58    if (!is_low_surrogate(c16)) {
59      return reset_and_return_illegal(EINVAL, state);
60    }
61
62    char32_t c32 = ((mbstate_get_byte(state, 3) << 16) |
63                    (mbstate_get_byte(state, 2) << 8) |
64                    (c16 & ~0xdc00)) + 0x10000;
65    return reset_and_return(c32rtomb(s, c32, NULL), state);
66  }
67}
68