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      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 
     35 static inline constexpr bool is_high_surrogate(char16_t c16) {
     36   return c16 >= 0xd800 && c16 < 0xdc00;
     37 }
     38 
     39 static inline constexpr bool is_low_surrogate(char16_t c16) {
     40   return c16 >= 0xdc00 && c16 < 0xe000;
     41 }
     42 
     43 size_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