From: Jiri Slaby <jslaby@suse.cz>
To: gregkh@linuxfoundation.org
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH 13/38] vt: rearrange vc_translate_unicode
Date: Mon, 15 Jun 2020 09:48:45 +0200 [thread overview]
Message-ID: <20200615074910.19267-13-jslaby@suse.cz> (raw)
In-Reply-To: <20200615074910.19267-1-jslaby@suse.cz>
The code was too overcomplicated. Extract vc_sanitize_unicode to a
separate function and flatten the code. I believe the code is
straightforward now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/vt/vt.c | 121 +++++++++++++++++++++++---------------------
1 file changed, 64 insertions(+), 57 deletions(-)
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index caaad820413a..5004242d601b 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2572,6 +2572,19 @@ static inline int vc_translate_ascii(const struct vc_data *vc, int c)
return c;
}
+
+/**
+ * vc_sanitize_unicode -- Replace invalid Unicode code points with U+FFFD
+ * @c: the received character, or U+FFFD for invalid sequences.
+ */
+static inline int vc_sanitize_unicode(const int c)
+{
+ if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
+ return 0xfffd;
+
+ return c;
+}
+
/**
* vc_translate_unicode -- Combine UTF-8 into Unicode in @vc_utf_char
*
@@ -2586,69 +2599,63 @@ static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
0x001fffff, 0x03ffffff, 0x7fffffff
};
+ /* Continuation byte received */
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;
+ /* Unexpected continuation byte? */
+ if (!vc->vc_utf_count)
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;
+
+ vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
+ vc->vc_npar++;
+ if (--vc->vc_utf_count)
+ goto need_more_bytes;
+
+ /* 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 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 */
+
+ return vc_sanitize_unicode(c);
}
- /* 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)
+
+ /* 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;
+ }
- return c;
+ /* Nothing to do if an ASCII byte was received */
+ if (c <= 0x7f)
+ return c;
+
+ /* 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;
+ }
+
+need_more_bytes:
+ return -1;
}
/* acquires console_lock */
--
2.27.0
next prev parent reply other threads:[~2020-06-15 7:50 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 7:48 [PATCH 01/38] vc: separate state Jiri Slaby
2020-06-15 7:48 ` [PATCH 02/38] vt: introduce enum vc_intensity for intensity Jiri Slaby
2020-06-15 7:48 ` [PATCH 03/38] vc: switch state to bool Jiri Slaby
2020-06-15 7:48 ` [PATCH 04/38] vt: deduplicate setGx code Jiri Slaby
2020-06-15 7:48 ` [PATCH 05/38] vt: switch G0/1_charset to an array Jiri Slaby
2020-06-15 7:48 ` [PATCH 06/38] vt: convert vc_tab_stop to bitmap Jiri Slaby
2020-06-15 7:48 ` [PATCH 07/38] vt: remove 25 years stale comment Jiri Slaby
2020-06-15 7:48 ` [PATCH 08/38] vt: use tty_insert_flip_string in respond_string Jiri Slaby
2020-06-15 7:48 ` [PATCH 09/38] vt: get rid of VT10.ID macros Jiri Slaby
2020-06-15 7:48 ` [PATCH 10/38] vt: move vc_translate to vt.c and rename it Jiri Slaby
2020-06-15 7:48 ` [PATCH 11/38] vt: use modern types in do_con_write Jiri Slaby
2020-06-15 7:48 ` [PATCH 12/38] vt: separate unicode handling into vc_translate_unicode Jiri Slaby
2020-06-15 7:48 ` Jiri Slaby [this message]
2020-06-15 7:48 ` [PATCH 14/38] vt: extract attribute inversion to vc_invert_attr Jiri Slaby
2020-06-15 7:48 ` [PATCH 15/38] vt: move rescan_last_byte label earlier Jiri Slaby
2020-06-15 7:48 ` [PATCH 16/38] vc: move translation out of do_con_write Jiri Slaby
2020-06-15 7:48 ` [PATCH 17/38] vc: introduce struct vc_draw_region Jiri Slaby
2020-06-15 7:48 ` [PATCH 18/38] vc: extract detecting control characters from do_con_write Jiri Slaby
2020-06-15 7:48 ` [PATCH 19/38] vc: move normal char processing " Jiri Slaby
2020-06-15 7:48 ` [PATCH 20/38] vc: simplify condition in vc_con_write_normal Jiri Slaby
2020-06-15 7:48 ` [PATCH 21/38] vt: simplify vc_attr handling " Jiri Slaby
2020-06-15 7:48 ` [PATCH 22/38] vt: make tc write more obvious " Jiri Slaby
2020-06-15 7:48 ` [PATCH 23/38] vt: synchronize types and use min in csi_X Jiri Slaby
2020-06-15 7:48 ` [PATCH 24/38] vt: whitespace and paren cleanup in add_softcursor Jiri Slaby
2020-06-15 7:48 ` [PATCH 25/38] vt: redefine world of cursor macros Jiri Slaby
2020-06-15 7:48 ` [PATCH 26/38] vt: use newly defined CUR_* macros Jiri Slaby
2020-06-15 20:31 ` Helge Deller
2020-06-15 7:48 ` [PATCH 27/38] vt: remove superfluous parens in invert_screen and build_attr Jiri Slaby
2020-06-15 7:49 ` [PATCH 28/38] vt: simplify noncolor attributes in build_attr Jiri Slaby
2020-06-15 7:49 ` [PATCH 29/38] vt_ioctl: eliminate ret & breaks in vt_ioctl Jiri Slaby
2020-06-15 7:49 ` [PATCH 30/38] vt_ioctl: eliminate use of uival and ucval Jiri Slaby
2020-06-15 7:49 ` [PATCH 31/38] vt_ioctl: move K* ioctls to a separate function Jiri Slaby
2020-06-15 7:49 ` [PATCH 32/38] vt_ioctl: move io " Jiri Slaby
2020-06-15 7:49 ` [PATCH 33/38] vt_ioctl: move vt_setactivate out of vt_ioctl Jiri Slaby
2020-06-15 7:49 ` [PATCH 34/38] vt_ioctl: move vt_reldisp " Jiri Slaby
2020-06-15 7:49 ` [PATCH 35/38] vt_ioctl: move vt_resizex " Jiri Slaby
2020-06-15 7:49 ` [PATCH 36/38] vt_ioctl: move vt_io_fontreset out of vt_io_ioctl Jiri Slaby
2020-06-15 7:49 ` [PATCH 37/38] vt_ioctl: move vt_kdsetmode out of vt_k_ioctl Jiri Slaby
2020-06-15 7:49 ` [PATCH 38/38] vt_ioctl: move perm checks level up Jiri Slaby
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