root/maint/gnulib/lib/unilbrk/ulc-possible-linebreaks.c

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DEFINITIONS

This source file includes following definitions.
  1. ulc_possible_linebreaks
  2. read_file
  3. main

   1 /* Line breaking of strings.
   2    Copyright (C) 2001-2003, 2006-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2001.
   4 
   5    This file is free software.
   6    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   7    You can redistribute it and/or modify it under either
   8      - the terms of the GNU Lesser General Public License as published
   9        by the Free Software Foundation; either version 3, or (at your
  10        option) any later version, or
  11      - the terms of the GNU General Public License as published by the
  12        Free Software Foundation; either version 2, or (at your option)
  13        any later version, or
  14      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  15 
  16    This file is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License and the GNU General Public License
  20    for more details.
  21 
  22    You should have received a copy of the GNU Lesser General Public
  23    License and of the GNU General Public License along with this
  24    program.  If not, see <https://www.gnu.org/licenses/>.  */
  25 
  26 #include <config.h>
  27 
  28 /* Specification.  */
  29 #include "unilbrk.h"
  30 
  31 #include <stdlib.h>
  32 #include <string.h>
  33 
  34 #include "c-ctype.h"
  35 #include "uniconv.h"
  36 #include "unilbrk/ulc-common.h"
  37 
  38 /* Line breaking of a string in an arbitrary encoding.
  39 
  40    We convert the input string to Unicode.
  41 
  42    The standardized Unicode encodings are UTF-8, UCS-2, UCS-4, UTF-16,
  43    UTF-16BE, UTF-16LE, UTF-7.  UCS-2 supports only characters up to
  44    \U0000FFFF.  UTF-16 and variants support only characters up to
  45    \U0010FFFF.  UTF-7 is way too complex and not supported by glibc-2.1.
  46    UCS-4 specification leaves doubts about endianness and byte order mark.
  47    glibc currently interprets it as big endian without byte order mark,
  48    but this is not backed by an RFC.  So we use UTF-8. It supports
  49    characters up to \U7FFFFFFF and is unambiguously defined.  */
  50 
  51 void
  52 ulc_possible_linebreaks (const char *s, size_t n, const char *encoding,
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  53                          char *p)
  54 {
  55   if (n > 0)
  56     {
  57       if (is_utf8_encoding (encoding))
  58         u8_possible_linebreaks ((const uint8_t *) s, n, encoding, p);
  59       else
  60         {
  61           /* Convert the string to UTF-8 and build a translation table
  62              from offsets into s to offsets into the translated string.  */
  63           size_t *offsets = (size_t *) malloc (n * sizeof (size_t));
  64 
  65           if (offsets != NULL)
  66             {
  67               uint8_t *t;
  68               size_t m;
  69 
  70               t = u8_conv_from_encoding (encoding, iconveh_question_mark,
  71                                          s, n, offsets, NULL, &m);
  72               if (t != NULL)
  73                 {
  74                   char *q = (char *) (m > 0 ? malloc (m) : NULL);
  75 
  76                   if (m == 0 || q != NULL)
  77                     {
  78                       size_t i;
  79 
  80                       /* Determine the possible line breaks of the UTF-8
  81                          string.  */
  82                       u8_possible_linebreaks (t, m, encoding, q);
  83 
  84                       /* Translate the result back to the original string.  */
  85                       memset (p, UC_BREAK_PROHIBITED, n);
  86                       for (i = 0; i < n; i++)
  87                         if (offsets[i] != (size_t)(-1))
  88                           p[i] = q[offsets[i]];
  89 
  90                       free (q);
  91                       free (t);
  92                       free (offsets);
  93                       return;
  94                     }
  95                   free (t);
  96                 }
  97               free (offsets);
  98             }
  99 
 100           /* Impossible to convert.  */
 101 #if C_CTYPE_ASCII
 102           if (is_all_ascii (s, n))
 103             {
 104               /* ASCII is a subset of UTF-8.  */
 105               u8_possible_linebreaks ((const uint8_t *) s, n, encoding, p);
 106               return;
 107             }
 108 #endif
 109           /* We have a non-ASCII string and cannot convert it.
 110              Don't produce line breaks except those already present in the
 111              input string.  All we assume here is that the encoding is
 112              minimally ASCII compatible.  */
 113           {
 114             const char *s_end = s + n;
 115             while (s < s_end)
 116               {
 117                 *p = (*s == '\n' ? UC_BREAK_MANDATORY : UC_BREAK_PROHIBITED);
 118                 s++;
 119                 p++;
 120               }
 121           }
 122         }
 123     }
 124 }
 125 
 126 
 127 #ifdef TEST
 128 
 129 #include <stdio.h>
 130 #include <locale.h>
 131 #include <string.h>
 132 
 133 /* Read the contents of an input stream, and return it, terminated with a NUL
 134    byte. */
 135 char *
 136 read_file (FILE *stream)
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 137 {
 138 #define BUFSIZE 4096
 139   char *buf = NULL;
 140   int alloc = 0;
 141   int size = 0;
 142   int count;
 143 
 144   while (! feof (stream))
 145     {
 146       if (size + BUFSIZE > alloc)
 147         {
 148           alloc = alloc + alloc / 2;
 149           if (alloc < size + BUFSIZE)
 150             alloc = size + BUFSIZE;
 151           buf = realloc (buf, alloc);
 152           if (buf == NULL)
 153             {
 154               fprintf (stderr, "out of memory\n");
 155               exit (1);
 156             }
 157         }
 158       count = fread (buf + size, 1, BUFSIZE, stream);
 159       if (count == 0)
 160         {
 161           if (ferror (stream))
 162             {
 163               perror ("fread");
 164               exit (1);
 165             }
 166         }
 167       else
 168         size += count;
 169     }
 170   buf = realloc (buf, size + 1);
 171   if (buf == NULL)
 172     {
 173       fprintf (stderr, "out of memory\n");
 174       exit (1);
 175     }
 176   buf[size] = '\0';
 177   return buf;
 178 #undef BUFSIZE
 179 }
 180 
 181 int
 182 main (int argc, char * argv[])
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 183 {
 184   setlocale (LC_CTYPE, "");
 185   if (argc == 1)
 186     {
 187       /* Display all the break opportunities in the input string.  */
 188       char *input = read_file (stdin);
 189       int length = strlen (input);
 190       char *breaks = malloc (length);
 191       int i;
 192 
 193       ulc_possible_linebreaks (input, length, locale_charset (), breaks);
 194 
 195       for (i = 0; i < length; i++)
 196         {
 197           switch (breaks[i])
 198             {
 199             case UC_BREAK_POSSIBLE:
 200               putc ('|', stdout);
 201               break;
 202             case UC_BREAK_MANDATORY:
 203               break;
 204             case UC_BREAK_PROHIBITED:
 205               break;
 206             default:
 207               abort ();
 208             }
 209           putc (input[i], stdout);
 210         }
 211 
 212       free (breaks);
 213 
 214       return 0;
 215     }
 216   else
 217     return 1;
 218 }
 219 
 220 #endif /* TEST */

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