1 /* Conversion UCS-4 to UTF-8. 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: 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 "unistr.h" 22 23 #include "attribute.h" 24 25 int 26 u8_uctomb_aux (uint8_t *s, ucs4_t uc, ptrdiff_t n) /* */ 27 { 28 int count; 29 30 if (uc < 0x80) 31 /* The case n >= 1 is already handled by the caller. */ 32 return -2; 33 else if (uc < 0x800) 34 count = 2; 35 else if (uc < 0x10000) 36 { 37 if (uc < 0xd800 || uc >= 0xe000) 38 count = 3; 39 else 40 return -1; 41 } 42 else if (uc < 0x110000) 43 count = 4; 44 else 45 return -1; 46 47 if (n < count) 48 return -2; 49 50 switch (count) /* note: code falls through cases! */ 51 { 52 case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000; 53 FALLTHROUGH; 54 case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800; 55 FALLTHROUGH; 56 case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0; 57 /*case 1:*/ s[0] = uc; 58 } 59 return count; 60 }