diff options
Diffstat (limited to 'lib/unilbrk/ulc-possible-linebreaks.c')
| -rw-r--r-- | lib/unilbrk/ulc-possible-linebreaks.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/lib/unilbrk/ulc-possible-linebreaks.c b/lib/unilbrk/ulc-possible-linebreaks.c new file mode 100644 index 00000000..cb952419 --- /dev/null +++ b/lib/unilbrk/ulc-possible-linebreaks.c @@ -0,0 +1,212 @@ +/* Line breaking of strings. + Copyright (C) 2001-2003, 2006-2009 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2001. + + This program is free software: you can redistribute it and/or modify it + under the terms of the GNU Lesser 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include "unilbrk.h" + +#include <stdlib.h> +#include <string.h> + +#include "c-ctype.h" +#include "uniconv.h" +#include "unilbrk/ulc-common.h" + +/* Line breaking of a string in an arbitrary encoding. + + We convert the input string to Unicode. + + The standardized Unicode encodings are UTF-8, UCS-2, UCS-4, UTF-16, + UTF-16BE, UTF-16LE, UTF-7. UCS-2 supports only characters up to + \U0000FFFF. UTF-16 and variants support only characters up to + \U0010FFFF. UTF-7 is way too complex and not supported by glibc-2.1. + UCS-4 specification leaves doubts about endianness and byte order mark. + glibc currently interprets it as big endian without byte order mark, + but this is not backed by an RFC. So we use UTF-8. It supports + characters up to \U7FFFFFFF and is unambiguously defined. */ + +void +ulc_possible_linebreaks (const char *s, size_t n, const char *encoding, + char *p) +{ + if (n > 0) + { + if (is_utf8_encoding (encoding)) + u8_possible_linebreaks ((const uint8_t *) s, n, encoding, p); + else + { + /* Convert the string to UTF-8 and build a translation table + from offsets into s to offsets into the translated string. */ + size_t *offsets = (size_t *) malloc (n * sizeof (size_t)); + + if (offsets != NULL) + { + uint8_t *t; + size_t m; + + t = u8_conv_from_encoding (encoding, iconveh_question_mark, + s, n, offsets, NULL, &m); + if (t != NULL) + { + char *q = (char *) (m > 0 ? malloc (m) : NULL); + + if (m == 0 || q != NULL) + { + size_t i; + + /* Determine the possible line breaks of the UTF-8 + string. */ + u8_possible_linebreaks (t, m, encoding, q); + + /* Translate the result back to the original string. */ + memset (p, UC_BREAK_PROHIBITED, n); + for (i = 0; i < n; i++) + if (offsets[i] != (size_t)(-1)) + p[i] = q[offsets[i]]; + + free (q); + free (t); + free (offsets); + return; + } + free (t); + } + free (offsets); + } + + /* Impossible to convert. */ +#if C_CTYPE_ASCII + if (is_all_ascii (s, n)) + { + /* ASCII is a subset of UTF-8. */ + u8_possible_linebreaks ((const uint8_t *) s, n, encoding, p); + return; + } +#endif + /* We have a non-ASCII string and cannot convert it. + Don't produce line breaks except those already present in the + input string. All we assume here is that the encoding is + minimally ASCII compatible. */ + { + const char *s_end = s + n; + while (s < s_end) + { + *p = (*s == '\n' ? UC_BREAK_MANDATORY : UC_BREAK_PROHIBITED); + s++; + p++; + } + } + } + } +} + + +#ifdef TEST + +#include <stdio.h> +#include <locale.h> +#include <string.h> + +/* Read the contents of an input stream, and return it, terminated with a NUL + byte. */ +char * +read_file (FILE *stream) +{ +#define BUFSIZE 4096 + char *buf = NULL; + int alloc = 0; + int size = 0; + int count; + + while (! feof (stream)) + { + if (size + BUFSIZE > alloc) + { + alloc = alloc + alloc / 2; + if (alloc < size + BUFSIZE) + alloc = size + BUFSIZE; + buf = realloc (buf, alloc); + if (buf == NULL) + { + fprintf (stderr, "out of memory\n"); + exit (1); + } + } + count = fread (buf + size, 1, BUFSIZE, stream); + if (count == 0) + { + if (ferror (stream)) + { + perror ("fread"); + exit (1); + } + } + else + size += count; + } + buf = realloc (buf, size + 1); + if (buf == NULL) + { + fprintf (stderr, "out of memory\n"); + exit (1); + } + buf[size] = '\0'; + return buf; +#undef BUFSIZE +} + +int +main (int argc, char * argv[]) +{ + setlocale (LC_CTYPE, ""); + if (argc == 1) + { + /* Display all the break opportunities in the input string. */ + char *input = read_file (stdin); + int length = strlen (input); + char *breaks = malloc (length); + int i; + + ulc_possible_linebreaks (input, length, locale_charset (), breaks); + + for (i = 0; i < length; i++) + { + switch (breaks[i]) + { + case UC_BREAK_POSSIBLE: + putc ('|', stdout); + break; + case UC_BREAK_MANDATORY: + break; + case UC_BREAK_PROHIBITED: + break; + default: + abort (); + } + putc (input[i], stdout); + } + + free (breaks); + + return 0; + } + else + return 1; +} + +#endif /* TEST */ |