1 /* Conversion UCS-4 to UTF-8. 2 Copyright (C) 2002, 2006-2007, 2009-2018 Free Software Foundation, Inc. 3 Written by Bruno Haible <bruno@clisp.org>, 2002. 4 5 This program is free software: you can redistribute it and/or modify it 6 under the terms of the GNU General Public License as published 7 by the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program 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 GNU 13 General Public License for more details. 14 15 You should have received a copy of the GNU 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 #ifndef FALLTHROUGH 24 # if __GNUC__ < 7 25 # define FALLTHROUGH ((void) 0) 26 # else 27 # define FALLTHROUGH __attribute__ ((__fallthrough__)) 28 # endif 29 #endif 30 31 int 32 u8_uctomb_aux (uint8_t *s, ucs4_t uc, int n) 33 { 34 int count; 35 36 if (uc < 0x80) 37 /* The case n >= 1 is already handled by the caller. */ 38 return -2; 39 else if (uc < 0x800) 40 count = 2; 41 else if (uc < 0x10000) 42 { 43 if (uc < 0xd800 || uc >= 0xe000) 44 count = 3; 45 else 46 return -1; 47 } 48 else if (uc < 0x110000) 49 count = 4; 50 else 51 return -1; 52 53 if (n < count) 54 return -2; 55 56 switch (count) /* note: code falls through cases! */ 57 { 58 case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000; 59 FALLTHROUGH; 60 case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800; 61 FALLTHROUGH; 62 case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0; 63 /*case 1:*/ s[0] = uc; 64 } 65 return count; 66 } 67