1 /* Conversion UCS-4 to UTF-8. 2 Copyright (C) 2002 Free Software Foundation, Inc. 3 Written by Bruno Haible <haible@clisp.cons.org>, 2002. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 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 13 GNU 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, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 18 19 20 #include <stddef.h> 21 22 /* Return the length (number of units) of the UTF-8 representation of uc, 23 after storing it at S. Return -1 upon failure, -2 if the number of 24 available units, N, is too small. */ 25 static int 26 u8_uctomb_aux (unsigned char *s, unsigned int uc, int n) 27 { 28 int count; 29 30 if (uc < 0x80) 31 count = 1; 32 else if (uc < 0x800) 33 count = 2; 34 else if (uc < 0x10000) 35 count = 3; 36 #if 0 37 else if (uc < 0x200000) 38 count = 4; 39 else if (uc < 0x4000000) 40 count = 5; 41 else if (uc <= 0x7fffffff) 42 count = 6; 43 #else 44 else if (uc < 0x110000) 45 count = 4; 46 #endif 47 else 48 return -1; 49 50 if (n < count) 51 return -2; 52 53 switch (count) /* note: code falls through cases! */ 54 { 55 #if 0 56 case 6: s[5] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x4000000; 57 case 5: s[4] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x200000; 58 #endif 59 case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000; 60 case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800; 61 case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0; 62 case 1: s[0] = uc; 63 } 64 return count; 65 } 66 67 static inline int 68 u8_uctomb (unsigned char *s, unsigned int uc, int n) 69 { 70 if (uc < 0x80 && n > 0) 71 { 72 s[0] = uc; 73 return 1; 74 } 75 else 76 return u8_uctomb_aux (s, uc, n); 77 } 78