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Diffstat (limited to 'lib/mbswidth.c')
| -rw-r--r-- | lib/mbswidth.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/lib/mbswidth.c b/lib/mbswidth.c new file mode 100644 index 0000000..98a5b94 --- /dev/null +++ b/lib/mbswidth.c @@ -0,0 +1,193 @@ +/* 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; +} |