1 /* Formatted output to strings. 2 Copyright (C) 1999, 2002, 2006-2021 Free Software Foundation, Inc. 3 4 This file is free software. 5 It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+". 6 You can redistribute it and/or modify it under either 7 - the terms of the GNU Lesser General Public License as published 8 by the Free Software Foundation; either version 3, or (at your 9 option) any later version, or 10 - the terms of the GNU General Public License as published by the 11 Free Software Foundation; either version 2, or (at your option) 12 any later version, or 13 - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+". 14 15 This file is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 Lesser General Public License and the GNU General Public License 19 for more details. 20 21 You should have received a copy of the GNU Lesser General Public 22 License and of the GNU General Public License along with this 23 program. If not, see <https://www.gnu.org/licenses/>. */ 24 25 #ifndef SIZE_MAX 26 # define SIZE_MAX ((size_t) -1) 27 #endif 28 29 int 30 VSPRINTF (DCHAR_T *buf, const FCHAR_T *format, va_list args) /* */ 31 { 32 /* Pass an infinite length. But note that *vasnprintf may fail if the buffer 33 argument is larger than INT_MAX (if that fits into a 'size_t' at all). 34 Also note that glibc's iconv fails with E2BIG when we pass a length that 35 is so large that buf + length wraps around, i.e. 36 (uintptr_t) (buf + length) < (uintptr_t) buf. */ 37 size_t length; 38 DCHAR_T *result; 39 40 /* Set length = min (SIZE_MAX, INT_MAX, - (uintptr_t) buf - 1). */ 41 length = (SIZE_MAX < INT_MAX ? SIZE_MAX : INT_MAX); 42 if (length > (~ (uintptr_t) buf) / sizeof (DCHAR_T)) 43 length = (~ (uintptr_t) buf) / sizeof (DCHAR_T); 44 45 result = VASNPRINTF (buf, &length, format, args); 46 if (result == NULL) 47 return -1; 48 49 /* The infinite buffer size guarantees that the result is not malloc()ed. */ 50 if (result != buf) 51 { 52 /* length is near SIZE_MAX. */ 53 free (result); 54 errno = EOVERFLOW; 55 return -1; 56 } 57 58 if (length > INT_MAX) 59 { 60 errno = EOVERFLOW; 61 return -1; 62 } 63 64 /* Return the number of resulting units, excluding the trailing NUL. */ 65 return length; 66 }