tmux/utf8.c

/* $OpenBSD$ */

/*
 * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include "tmux.h"

static int	utf8_width(wchar_t);

/* Set a single character. */
void
utf8_set(struct utf8_data *ud, u_char ch)
{
	static const struct utf8_data empty = { { 0 }, 1, 1, 1 };

	memcpy(ud, &empty, sizeof *ud);
	*ud->data = ch;
}

/* Copy UTF-8 character. */
void
utf8_copy(struct utf8_data *to, const struct utf8_data *from)
{
	u_int	i;

	memcpy(to, from, sizeof *to);

	for (i = to->size; i < sizeof to->data; i++)
		to->data[i] = '\0';
}

/*
 * Open UTF-8 sequence.
 *
 * 11000010-11011111 C2-DF start of 2-byte sequence
 * 11100000-11101111 E0-EF start of 3-byte sequence
 * 11110000-11110100 F0-F4 start of 4-byte sequence
 */
enum utf8_state
utf8_open(struct utf8_data *ud, u_char ch)
{
	memset(ud, 0, sizeof *ud);
	if (ch >= 0xc2 && ch <= 0xdf)
		ud->size = 2;
	else if (ch >= 0xe0 && ch <= 0xef)
		ud->size = 3;
	else if (ch >= 0xf0 && ch <= 0xf4)
		ud->size = 4;
	else
		return (UTF8_ERROR);
	utf8_append(ud, ch);
	return (UTF8_MORE);
}

/* Append character to UTF-8, closing if finished. */
enum utf8_state
utf8_append(struct utf8_data *ud, u_char ch)
{
	wchar_t	wc;
	int	width;

	if (ud->have >= ud->size)
		fatalx("UTF-8 character overflow");
	if (ud->size > sizeof ud->data)
		fatalx("UTF-8 character size too large");

	if (ud->have != 0 && (ch & 0xc0) != 0x80)
		ud->width = 0xff;

	ud->data[ud->have++] = ch;
	if (ud->have != ud->size)
		return (UTF8_MORE);

	if (ud->width == 0xff)
		return (UTF8_ERROR);

	if (utf8_combine(ud, &wc) != UTF8_DONE)
		return (UTF8_ERROR);
	if ((width = utf8_width(wc)) < 0)
		return (UTF8_ERROR);
	ud->width = width;

	return (UTF8_DONE);
}

/* Get width of Unicode character. */
static int
utf8_width(wchar_t wc)
{
	int	width;

	width = wcwidth(wc);
	if (width < 0 || width > 0xff) {
		log_debug("Unicode %04x, wcwidth() %d", wc, width);

#ifndef __OpenBSD__
		/*
		 * Many platforms (particularly and inevitably OS X) have no
		 * width for relatively common characters (wcwidth() returns
		 * -1); assume width 1 in this case. This will be wrong for
		 * genuinely nonprintable characters, but they should be
		 * rare. We may pass through stuff that ideally we would block,
		 * but this is no worse than sending the same to the terminal
		 * without tmux.
		 */
		if (width < 0)
			return (1);
#endif
		return (-1);
	}
	return (width);
}

/* Combine UTF-8 into Unicode. */
enum utf8_state
utf8_combine(const struct utf8_data *ud, wchar_t *wc)
{
	switch (mbtowc(wc, ud->data, ud->size)) {
	case -1:
		log_debug("UTF-8 %.*s, mbtowc() %d", (int)ud->size, ud->data,
		    errno);
		mbtowc(NULL, NULL, MB_CUR_MAX);
		return (UTF8_ERROR);
	case 0:
		return (UTF8_ERROR);
	default:
		return (UTF8_DONE);
	}
}

/* Split Unicode into UTF-8. */
enum utf8_state
utf8_split(wchar_t wc, struct utf8_data *ud)
{
	char	s[MB_LEN_MAX];
	int	slen;

	slen = wctomb(s, wc);
	if (slen <= 0 || slen > (int)sizeof ud->data)
		return (UTF8_ERROR);

	memcpy(ud->data, s, slen);
	ud->size = slen;

	ud->width = utf8_width(wc);
	return (UTF8_DONE);
}

/*
 * Encode len characters from src into dst, which is guaranteed to have four
 * bytes available for each character from src (for \abc or UTF-8) plus space
 * for \0.
 */
int
utf8_strvis(char *dst, const char *src, size_t len, int flag)
{
	struct utf8_data	 ud;
	const char		*start, *end;
	enum utf8_state		 more;
	size_t			 i;

	start = dst;
	end = src + len;

	while (src < end) {
		if ((more = utf8_open(&ud, *src)) == UTF8_MORE) {
			while (++src < end && more == UTF8_MORE)
				more = utf8_append(&ud, *src);
			if (more == UTF8_DONE) {
				/* UTF-8 character finished. */
				for (i = 0; i < ud.size; i++)
					*dst++ = ud.data[i];
				continue;
			}
			/* Not a complete, valid UTF-8 character. */
			src -= ud.have;
		}
		if (src < end - 1)
			dst = vis(dst, src[0], flag, src[1]);
		else if (src < end)
			dst = vis(dst, src[0], flag, '\0');
		src++;
	}

	*dst = '\0';
	return (dst - start);
}

/*
 * Sanitize a string, changing any UTF-8 characters to '_'. Caller should free
 * the returned string. Anything not valid printable ASCII or UTF-8 is
 * stripped.
 */
char *
utf8_sanitize(const char *src)
{
	char			*dst;
	size_t			 n;
	enum utf8_state		 more;
	struct utf8_data	 ud;
	u_int			 i;

	dst = NULL;

	n = 0;
	while (*src != '\0') {
		dst = xreallocarray(dst, n + 1, sizeof *dst);
		if ((more = utf8_open(&ud, *src)) == UTF8_MORE) {
			while (*++src != '\0' && more == UTF8_MORE)
				more = utf8_append(&ud, *src);
			if (more == UTF8_DONE) {
				dst = xreallocarray(dst, n + ud.width,
				    sizeof *dst);
				for (i = 0; i < ud.width; i++)
					dst[n++] = '_';
				continue;
			}
			src -= ud.have;
		}
		if (*src > 0x1f && *src < 0x7f)
			dst[n++] = *src;
		else
			dst[n++] = '_';
		src++;
	}

	dst = xreallocarray(dst, n + 1, sizeof *dst);
	dst[n] = '\0';
	return (dst);
}

/*
 * Convert a string into a buffer of UTF-8 characters. Terminated by size == 0.
 * Caller frees.
 */
struct utf8_data *
utf8_fromcstr(const char *src)
{
	struct utf8_data	*dst;
	size_t			 n;
	enum utf8_state		 more;

	dst = NULL;

	n = 0;
	while (*src != '\0') {
		dst = xreallocarray(dst, n + 1, sizeof *dst);
		if ((more = utf8_open(&dst[n], *src)) == UTF8_MORE) {
			while (*++src != '\0' && more == UTF8_MORE)
				more = utf8_append(&dst[n], *src);
			if (more == UTF8_DONE) {
				n++;
				continue;
			}
			src -= dst[n].have;
		}
		utf8_set(&dst[n], *src);
		n++;
		src++;
	}

	dst = xreallocarray(dst, n + 1, sizeof *dst);
	dst[n].size = 0;
	return (dst);
}

/* Convert from a buffer of UTF-8 characters into a string. Caller frees. */
char *
utf8_tocstr(struct utf8_data *src)
{
	char	*dst;
	size_t	 n;

	dst = NULL;

	n = 0;
	for(; src->size != 0; src++) {
		dst = xreallocarray(dst, n + src->size, 1);
		memcpy(dst + n, src->data, src->size);
		n += src->size;
	}

	dst = xreallocarray(dst, n + 1, 1);
	dst[n] = '\0';
	return (dst);
}

/* Get width of UTF-8 string. */
u_int
utf8_cstrwidth(const char *s)
{
	struct utf8_data	tmp;
	u_int			width;
	enum utf8_state		more;

	width = 0;
	while (*s != '\0') {
		if ((more = utf8_open(&tmp, *s)) == UTF8_MORE) {
			while (*++s != '\0' && more == UTF8_MORE)
				more = utf8_append(&tmp, *s);
			if (more == UTF8_DONE) {
				width += tmp.width;
				continue;
			}
			s -= tmp.have;
		}
		if (*s > 0x1f && *s != 0x7f)
			width++;
		s++;
	}
	return (width);
}

/* Trim UTF-8 string to width. Caller frees. */
char *
utf8_trimcstr(const char *s, u_int width)
{
	struct utf8_data	*tmp, *next;
	char			*out;
	u_int			 at;

	tmp = utf8_fromcstr(s);

	at = 0;
	for (next = tmp; next->size != 0; next++) {
		if (at + next->width > width) {
			next->size = 0;
			break;
		}
		at += next->width;
	}

	out = utf8_tocstr(tmp);
	free(tmp);
	return (out);
}

/* Trim UTF-8 string to width. Caller frees. */
char *
utf8_rtrimcstr(const char *s, u_int width)
{
	struct utf8_data	*tmp, *next, *end;
	char			*out;
	u_int			 at;

	tmp = utf8_fromcstr(s);

	for (end = tmp; end->size != 0; end++)
		/* nothing */;
	if (end == tmp) {
		free(tmp);
		return (xstrdup(""));
	}
	next = end - 1;

	at = 0;
	for (;;)
	{
		if (at + next->width > width) {
			next++;
			break;
		}
		at += next->width;

		if (next == tmp)
			break;
		next--;
	}

	out = utf8_tocstr(next);
	free(tmp);
	return (out);
}

/* Pad UTF-8 string to width. Caller frees. */
char *
utf8_padcstr(const char *s, u_int width)
{
	size_t	 slen;
	char	*out;
	u_int	  n, i;

	n = utf8_cstrwidth(s);
	if (n >= width)
		return (xstrdup(s));

	slen = strlen(s);
	out = xmalloc(slen + 1 + (width - n));
	memcpy(out, s, slen);
	for (i = n; i < width; i++)
		out[slen++] = ' ';
	out[slen] = '\0';
	return (out);
}