| /* Convert UTF-16 string to UTF-8 string. |
| Copyright (C) 2002, 2006-2007, 2009-2019 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2002. |
| |
| This program is free software: you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published |
| by the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include "unistr.h" |
| |
| #define FUNC u16_to_u8 |
| #define SRC_UNIT uint16_t |
| #define DST_UNIT uint8_t |
| |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| DST_UNIT * |
| FUNC (const SRC_UNIT *s, size_t n, DST_UNIT *resultbuf, size_t *lengthp) |
| { |
| const SRC_UNIT *s_end = s + n; |
| /* Output string accumulator. */ |
| DST_UNIT *result; |
| size_t allocated; |
| size_t length; |
| |
| if (resultbuf != NULL) |
| { |
| result = resultbuf; |
| allocated = *lengthp; |
| } |
| else |
| { |
| result = NULL; |
| allocated = 0; |
| } |
| length = 0; |
| /* Invariants: |
| result is either == resultbuf or == NULL or malloc-allocated. |
| If length > 0, then result != NULL. */ |
| |
| while (s < s_end) |
| { |
| ucs4_t uc; |
| int count; |
| |
| /* Fetch a Unicode character from the input string. */ |
| count = u16_mbtoucr (&uc, s, s_end - s); |
| if (count < 0) |
| { |
| if (!(result == resultbuf || result == NULL)) |
| free (result); |
| errno = EILSEQ; |
| return NULL; |
| } |
| s += count; |
| |
| /* Store it in the output string. */ |
| count = u8_uctomb (result + length, uc, allocated - length); |
| if (count == -1) |
| { |
| if (!(result == resultbuf || result == NULL)) |
| free (result); |
| errno = EILSEQ; |
| return NULL; |
| } |
| if (count == -2) |
| { |
| DST_UNIT *memory; |
| |
| allocated = (allocated > 0 ? 2 * allocated : 12); |
| if (length + 6 > allocated) |
| allocated = length + 6; |
| if (result == resultbuf || result == NULL) |
| memory = (DST_UNIT *) malloc (allocated * sizeof (DST_UNIT)); |
| else |
| memory = |
| (DST_UNIT *) realloc (result, allocated * sizeof (DST_UNIT)); |
| |
| if (memory == NULL) |
| { |
| if (!(result == resultbuf || result == NULL)) |
| free (result); |
| errno = ENOMEM; |
| return NULL; |
| } |
| if (result == resultbuf && length > 0) |
| memcpy ((char *) memory, (char *) result, |
| length * sizeof (DST_UNIT)); |
| result = memory; |
| count = u8_uctomb (result + length, uc, allocated - length); |
| if (count < 0) |
| abort (); |
| } |
| length += count; |
| } |
| |
| if (length == 0) |
| { |
| if (result == NULL) |
| { |
| /* Return a non-NULL value. NULL means error. */ |
| result = (DST_UNIT *) malloc (1); |
| if (result == NULL) |
| { |
| errno = ENOMEM; |
| return NULL; |
| } |
| } |
| } |
| else if (result != resultbuf && length < allocated) |
| { |
| /* Shrink the allocated memory if possible. */ |
| DST_UNIT *memory; |
| |
| memory = (DST_UNIT *) realloc (result, length * sizeof (DST_UNIT)); |
| if (memory != NULL) |
| result = memory; |
| } |
| |
| *lengthp = length; |
| return result; |
| } |