diff options
author | Jiri Slaby <jslaby@suse.cz> | 2020-06-15 09:48:44 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-24 17:08:32 +0200 |
commit | 694d8a487c8bc2a0b35b9da951b0635c6a256ea6 (patch) | |
tree | 2dedfea799d5eb36c328e758ce14738fa3864728 /drivers/tty | |
parent | da823b2dc03749f0d1b2d051b37f222e5a3918d7 (diff) |
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>
Diffstat (limited to 'drivers/tty')
-rw-r--r-- | drivers/tty/vt/vt.c | 149 |
1 files changed, 81 insertions, 68 deletions
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index a9e4924fa675..caaad820413a 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -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 */ - 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 */ + tc = c = vc_translate_unicode(vc, c, &rescan); + if (tc == -1) 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); } |