1 /* Test for initial conversion state. 2 Copyright (C) 2008-2021 Free Software Foundation, Inc. 3 Written by Bruno Haible <bruno@clisp.org>, 2008. 4 5 This file is free software: you can redistribute it and/or modify 6 it under the terms of the GNU Lesser General Public License as 7 published by the Free Software Foundation; either version 2.1 of the 8 License, or (at your option) any later version. 9 10 This file is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public License 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 17 18 #include <config.h> 19 20 /* Specification. */ 21 #include <wchar.h> 22 23 #include "verify.h" 24 25 #if GNULIB_defined_mbstate_t 26 27 /* Platforms that lack mbsinit() also lack mbrlen(), mbrtowc(), mbsrtowcs() 28 and wcrtomb(), wcsrtombs(). 29 We assume that 30 - sizeof (mbstate_t) >= 4, 31 - only stateless encodings are supported (such as UTF-8 and EUC-JP, but 32 not ISO-2022 variants), 33 - for each encoding, the number of bytes for a wide character is <= 4. 34 (This maximum is attained for UTF-8, GB18030, EUC-TW.) 35 We define the meaning of mbstate_t as follows: 36 - In mb -> wc direction, mbstate_t's first byte contains the number of 37 buffered bytes (in the range 0..3), followed by up to 3 buffered bytes. 38 See mbrtowc.c. 39 - In wc -> mb direction, mbstate_t contains no information. In other 40 words, it is always in the initial state. */ 41 42 verify (sizeof (mbstate_t) >= 4); 43 44 int 45 mbsinit (const mbstate_t *ps) /* */ 46 { 47 const char *pstate = (const char *)ps; 48 49 return pstate == NULL || pstate[0] == 0; 50 } 51 52 #else 53 54 int 55 mbsinit (const mbstate_t *ps) /* */ 56 { 57 # if defined _WIN32 && !defined __CYGWIN__ 58 /* Native Windows. */ 59 /* MSVC defines 'mbstate_t' as an 8-byte struct; the first 4 bytes matter. 60 On mingw, 'mbstate_t' is sometimes defined as 'int', sometimes defined as 61 an 8-byte struct, of which the first 4 bytes matter. */ 62 return ps == NULL || *(const unsigned int *)ps == 0; 63 # else 64 /* Minix, HP-UX 11.00, Solaris 2.6, Interix, ... */ 65 /* Maybe this definition works, maybe not... */ 66 return ps == NULL || *(const char *)ps == 0; 67 # endif 68 } 69 70 #endif