1/* Convert UTF-16 string to UTF-8 string. 2 Copyright (C) 2002, 2006-2007, 2009-2010 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 Lesser 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 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 <http://www.gnu.org/licenses/>. */ 17 18#include <config.h> 19 20/* Specification. */ 21#include "unistr.h" 22 23#define FUNC u16_to_u8 24#define SRC_UNIT uint16_t 25#define DST_UNIT uint8_t 26 27#include <errno.h> 28#include <stdlib.h> 29#include <string.h> 30 31DST_UNIT * 32FUNC (const SRC_UNIT *s, size_t n, DST_UNIT *resultbuf, size_t *lengthp) 33{ 34 const SRC_UNIT *s_end = s + n; 35 /* Output string accumulator. */ 36 DST_UNIT *result; 37 size_t allocated; 38 size_t length; 39 40 if (resultbuf != NULL) 41 { 42 result = resultbuf; 43 allocated = *lengthp; 44 } 45 else 46 { 47 result = NULL; 48 allocated = 0; 49 } 50 length = 0; 51 /* Invariants: 52 result is either == resultbuf or == NULL or malloc-allocated. 53 If length > 0, then result != NULL. */ 54 55 while (s < s_end) 56 { 57 ucs4_t uc; 58 int count; 59 60 /* Fetch a Unicode character from the input string. */ 61 count = u16_mbtoucr (&uc, s, s_end - s); 62 if (count < 0) 63 { 64 if (!(result == resultbuf || result == NULL)) 65 free (result); 66 errno = EILSEQ; 67 return NULL; 68 } 69 s += count; 70 71 /* Store it in the output string. */ 72 count = u8_uctomb (result + length, uc, allocated - length); 73 if (count == -1) 74 { 75 if (!(result == resultbuf || result == NULL)) 76 free (result); 77 errno = EILSEQ; 78 return NULL; 79 } 80 if (count == -2) 81 { 82 DST_UNIT *memory; 83 84 allocated = (allocated > 0 ? 2 * allocated : 12); 85 if (length + 6 > allocated) 86 allocated = length + 6; 87 if (result == resultbuf || result == NULL) 88 memory = (DST_UNIT *) malloc (allocated * sizeof (DST_UNIT)); 89 else 90 memory = 91 (DST_UNIT *) realloc (result, allocated * sizeof (DST_UNIT)); 92 93 if (memory == NULL) 94 { 95 if (!(result == resultbuf || result == NULL)) 96 free (result); 97 errno = ENOMEM; 98 return NULL; 99 } 100 if (result == resultbuf && length > 0) 101 memcpy ((char *) memory, (char *) result, 102 length * sizeof (DST_UNIT)); 103 result = memory; 104 count = u8_uctomb (result + length, uc, allocated - length); 105 if (count < 0) 106 abort (); 107 } 108 length += count; 109 } 110 111 if (length == 0) 112 { 113 if (result == NULL) 114 { 115 /* Return a non-NULL value. NULL means error. */ 116 result = (DST_UNIT *) malloc (1); 117 if (result == NULL) 118 { 119 errno = ENOMEM; 120 return NULL; 121 } 122 } 123 } 124 else if (result != resultbuf && length < allocated) 125 { 126 /* Shrink the allocated memory if possible. */ 127 DST_UNIT *memory; 128 129 memory = (DST_UNIT *) realloc (result, length * sizeof (DST_UNIT)); 130 if (memory != NULL) 131 result = memory; 132 } 133 134 *lengthp = length; 135 return result; 136} 137