rm_/lib/mbswidth.c
2022-07-28 14:16:50 +08:00

194 lines
6.2 KiB
C

/* Determine the number of screen columns needed for a string.
Copyright (C) 2000-2022 Free Software Foundation, Inc.
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/>. */
/* Written by Bruno Haible <haible@clisp.cons.org>. */
#include <config.h>
/* Specification. */
#include "mbswidth.h"
/* Get MB_CUR_MAX. */
#include <stdlib.h>
#include <string.h>
/* Get isprint(). */
#include <ctype.h>
/* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth(). */
#include <wchar.h>
/* Get iswcntrl(). */
#include <wctype.h>
/* Get INT_MAX. */
#include <limits.h>
/* Returns the number of columns needed to represent the multibyte
character string pointed to by STRING. If a non-printable character
occurs, and MBSW_REJECT_UNPRINTABLE is specified, -1 is returned.
With flags = MBSW_REJECT_INVALID | MBSW_REJECT_UNPRINTABLE, this is
the multibyte analogue of the wcswidth function. */
int
mbswidth (const char *string, int flags)
{
return mbsnwidth (string, strlen (string), flags);
}
/* Returns the number of columns needed to represent the multibyte
character string pointed to by STRING of length NBYTES. If a
non-printable character occurs, and MBSW_REJECT_UNPRINTABLE is
specified, -1 is returned. */
int
mbsnwidth (const char *string, size_t nbytes, int flags)
{
const char *p = string;
const char *plimit = p + nbytes;
int width;
width = 0;
if (MB_CUR_MAX > 1)
{
while (p < plimit)
switch (*p)
{
case ' ': case '!': case '"': case '#': case '%':
case '&': case '\'': case '(': case ')': case '*':
case '+': case ',': case '-': case '.': case '/':
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case ':': case ';': case '<': case '=': case '>':
case '?':
case 'A': case 'B': case 'C': case 'D': case 'E':
case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O':
case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y':
case 'Z':
case '[': case '\\': case ']': case '^': case '_':
case 'a': case 'b': case 'c': case 'd': case 'e':
case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o':
case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y':
case 'z': case '{': case '|': case '}': case '~':
/* These characters are printable ASCII characters. */
p++;
width++;
break;
default:
/* If we have a multibyte sequence, scan it up to its end. */
{
mbstate_t mbstate;
memset (&mbstate, 0, sizeof mbstate);
do
{
wchar_t wc;
size_t bytes;
int w;
bytes = mbrtowc (&wc, p, plimit - p, &mbstate);
if (bytes == (size_t) -1)
/* An invalid multibyte sequence was encountered. */
{
if (!(flags & MBSW_REJECT_INVALID))
{
p++;
width++;
break;
}
else
return -1;
}
if (bytes == (size_t) -2)
/* An incomplete multibyte character at the end. */
{
if (!(flags & MBSW_REJECT_INVALID))
{
p = plimit;
width++;
break;
}
else
return -1;
}
if (bytes == 0)
/* A null wide character was encountered. */
bytes = 1;
w = wcwidth (wc);
if (w >= 0)
/* A printable multibyte character. */
{
if (w > INT_MAX - width)
goto overflow;
width += w;
}
else
/* An unprintable multibyte character. */
if (!(flags & MBSW_REJECT_UNPRINTABLE))
{
if (!iswcntrl (wc))
{
if (width == INT_MAX)
goto overflow;
width++;
}
}
else
return -1;
p += bytes;
}
while (! mbsinit (&mbstate));
}
break;
}
return width;
}
while (p < plimit)
{
unsigned char c = (unsigned char) *p++;
if (isprint (c))
{
if (width == INT_MAX)
goto overflow;
width++;
}
else if (!(flags & MBSW_REJECT_UNPRINTABLE))
{
if (!iscntrl (c))
{
if (width == INT_MAX)
goto overflow;
width++;
}
}
else
return -1;
}
return width;
overflow:
return INT_MAX;
}