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vt: separate unicode handling into vc_translate_unicode 

do_con_write is complicated enough. Extract unicode handling to a
separate function. For do_con_write, 249 LOCs lowered to 183 lines.

Use diff -w -b to see the difference is neligible -- mostly whitespace
and use of 'return's instead of 'continue's.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-12-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2020-06-15 09:48:44 +02:00 committed by Greg Kroah-Hartman
parent da823b2dc0
commit 694d8a487c
1 changed files with 81 additions and 68 deletions
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149
drivers/tty/vt/vt.c
View File

@ -2572,6 +2572,85 @@ static inline int vc_translate_ascii(const struct vc_data *vc, int c)
return c;
}
/**
* vc_translate_unicode -- Combine UTF-8 into Unicode in @vc_utf_char
*
* @vc_utf_char is the being-constructed unicode character.
* @vc_utf_count is the number of continuation bytes still expected to arrive.
* @vc_npar is the number of continuation bytes arrived so far.
*/
static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
{
static const u32 utf8_length_changes[] = {
0x0000007f, 0x000007ff, 0x0000ffff,
0x001fffff, 0x03ffffff, 0x7fffffff
};
if ((c & 0xc0) == 0x80) {
/* Continuation byte received */
if (vc->vc_utf_count) {
vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
vc->vc_npar++;
if (--vc->vc_utf_count) {
/* Still need some bytes */
return -1;
}
/* Got a whole character */
c = vc->vc_utf_char;
/* Reject overlong sequences */
if (c <= utf8_length_changes[vc->vc_npar - 1] ||
c > utf8_length_changes[vc->vc_npar])
return 0xfffd;
} else {
/* Unexpected continuation byte */
vc->vc_utf_count = 0;
return 0xfffd;
}
} else {
/* Single ASCII byte or first byte of a sequence received */
if (vc->vc_utf_count) {
/* Continuation byte expected */
*rescan = true;
vc->vc_utf_count = 0;
return 0xfffd;
} else if (c > 0x7f) {
/* First byte of a multibyte sequence received */
vc->vc_npar = 0;
if ((c & 0xe0) == 0xc0) {
vc->vc_utf_count = 1;
vc->vc_utf_char = (c & 0x1f);
} else if ((c & 0xf0) == 0xe0) {
vc->vc_utf_count = 2;
vc->vc_utf_char = (c & 0x0f);
} else if ((c & 0xf8) == 0xf0) {
vc->vc_utf_count = 3;
vc->vc_utf_char = (c & 0x07);
} else if ((c & 0xfc) == 0xf8) {
vc->vc_utf_count = 4;
vc->vc_utf_char = (c & 0x03);
} else if ((c & 0xfe) == 0xfc) {
vc->vc_utf_count = 5;
vc->vc_utf_char = (c & 0x01);
} else {
/* 254 and 255 are invalid */
return 0xfffd;
}
if (vc->vc_utf_count) {
/* Still need some bytes */
return -1;
}
}
/* Nothing to do if an ASCII byte was received */
}
/* End of UTF-8 decoding. */
/* c is the received character, or U+FFFD for invalid sequences. */
/* Replace invalid Unicode code points with U+FFFD too */
if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
return 0xfffd;
return c;
}
/* acquires console_lock */
static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
@ -2628,76 +2707,10 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co
if (vc->vc_state != ESnormal) {
tc = c;
} else if (vc->vc_utf && !vc->vc_disp_ctrl) {
/* Combine UTF-8 into Unicode in vc_utf_char.
* vc_utf_count is the number of continuation bytes still
* expected to arrive.
* vc_npar is the number of continuation bytes arrived so
* far
*/
rescan_last_byte:
if ((c & 0xc0) == 0x80) {
/* Continuation byte received */
static const uint32_t utf8_length_changes[] = { 0x0000007f, 0x000007ff, 0x0000ffff, 0x001fffff, 0x03ffffff, 0x7fffffff };
if (vc->vc_utf_count) {
vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
vc->vc_npar++;
if (--vc->vc_utf_count) {
/* Still need some bytes */
tc = c = vc_translate_unicode(vc, c, &rescan);
if (tc == -1)
continue;
}
/* Got a whole character */
c = vc->vc_utf_char;
/* Reject overlong sequences */
if (c <= utf8_length_changes[vc->vc_npar - 1] ||
c > utf8_length_changes[vc->vc_npar])
c = 0xfffd;
} else {
/* Unexpected continuation byte */
vc->vc_utf_count = 0;
c = 0xfffd;
}
} else {
/* Single ASCII byte or first byte of a sequence received */
if (vc->vc_utf_count) {
/* Continuation byte expected */
rescan = true;
vc->vc_utf_count = 0;
c = 0xfffd;
} else if (c > 0x7f) {
/* First byte of a multibyte sequence received */
vc->vc_npar = 0;
if ((c & 0xe0) == 0xc0) {
vc->vc_utf_count = 1;
vc->vc_utf_char = (c & 0x1f);
} else if ((c & 0xf0) == 0xe0) {
vc->vc_utf_count = 2;
vc->vc_utf_char = (c & 0x0f);
} else if ((c & 0xf8) == 0xf0) {
vc->vc_utf_count = 3;
vc->vc_utf_char = (c & 0x07);
} else if ((c & 0xfc) == 0xf8) {
vc->vc_utf_count = 4;
vc->vc_utf_char = (c & 0x03);
} else if ((c & 0xfe) == 0xfc) {
vc->vc_utf_count = 5;
vc->vc_utf_char = (c & 0x01);
} else {
/* 254 and 255 are invalid */
c = 0xfffd;
}
if (vc->vc_utf_count) {
/* Still need some bytes */
continue;
}
}
/* Nothing to do if an ASCII byte was received */
}
/* End of UTF-8 decoding. */
/* c is the received character, or U+FFFD for invalid sequences. */
/* Replace invalid Unicode code points with U+FFFD too */
if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
c = 0xfffd;
tc = c;
} else { /* no utf or alternate charset mode */
tc = vc_translate_ascii(vc, c);
}