1 /* Check UTF-16 string. 2 Copyright (C) 2002, 2006-2007, 2009-2021 Free Software Foundation, Inc. 3 Written by Bruno Haible <bruno@clisp.org>, 2002. 4 5 This file is free software. 6 It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+". 7 You can redistribute it and/or modify it under either 8 - the terms of the GNU Lesser General Public License as published 9 by the Free Software Foundation; either version 3, or (at your 10 option) any later version, or 11 - the terms of the GNU General Public License as published by the 12 Free Software Foundation; either version 2, or (at your option) 13 any later version, or 14 - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+". 15 16 This file is distributed in the hope that it will be useful, 17 but WITHOUT ANY WARRANTY; without even the implied warranty of 18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 19 Lesser General Public License and the GNU General Public License 20 for more details. 21 22 You should have received a copy of the GNU Lesser General Public 23 License and of the GNU General Public License along with this 24 program. If not, see <https://www.gnu.org/licenses/>. */ 25 26 #include <config.h> 27 28 /* Specification. */ 29 #include "unistr.h" 30 31 const uint16_t * 32 u16_check (const uint16_t *s, size_t n) /* */ 33 { 34 const uint16_t *s_end = s + n; 35 36 while (s < s_end) 37 { 38 /* Keep in sync with unistr.h and u16-mbtouc-aux.c. */ 39 uint16_t c = *s; 40 41 if (c < 0xd800 || c >= 0xe000) 42 { 43 s++; 44 continue; 45 } 46 if (c < 0xdc00) 47 { 48 if (s + 2 <= s_end 49 && s[1] >= 0xdc00 && s[1] < 0xe000) 50 { 51 s += 2; 52 continue; 53 } 54 } 55 /* invalid or incomplete multibyte character */ 56 return s; 57 } 58 return NULL; 59 }