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vt: rearrange vc_translate_unicode
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> Link: https://lore.kernel.org/r/20200615074910.19267-13-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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drivers/tty/vt
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@ -2572,6 +2572,19 @@ static inline int vc_translate_ascii(const struct vc_data *vc, int c)
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return c;
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}
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/**
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* vc_sanitize_unicode -- Replace invalid Unicode code points with U+FFFD
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* @c: the received character, or U+FFFD for invalid sequences.
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*/
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static inline int vc_sanitize_unicode(const int c)
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{
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if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
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return 0xfffd;
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return c;
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}
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/**
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* vc_translate_unicode -- Combine UTF-8 into Unicode in @vc_utf_char
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*
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@ -2586,69 +2599,63 @@ static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
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0x001fffff, 0x03ffffff, 0x7fffffff
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};
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/* Continuation byte received */
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if ((c & 0xc0) == 0x80) {
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/* Continuation byte received */
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if (vc->vc_utf_count) {
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vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
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vc->vc_npar++;
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if (--vc->vc_utf_count) {
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/* Still need some bytes */
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return -1;
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}
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/* Got a whole character */
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c = vc->vc_utf_char;
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/* Reject overlong sequences */
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if (c <= utf8_length_changes[vc->vc_npar - 1] ||
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c > utf8_length_changes[vc->vc_npar])
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return 0xfffd;
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} else {
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/* Unexpected continuation byte */
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vc->vc_utf_count = 0;
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/* Unexpected continuation byte? */
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if (!vc->vc_utf_count)
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return 0xfffd;
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}
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} else {
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/* Single ASCII byte or first byte of a sequence received */
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if (vc->vc_utf_count) {
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/* Continuation byte expected */
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*rescan = true;
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vc->vc_utf_count = 0;
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return 0xfffd;
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} else if (c > 0x7f) {
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/* First byte of a multibyte sequence received */
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vc->vc_npar = 0;
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if ((c & 0xe0) == 0xc0) {
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vc->vc_utf_count = 1;
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vc->vc_utf_char = (c & 0x1f);
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} else if ((c & 0xf0) == 0xe0) {
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vc->vc_utf_count = 2;
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vc->vc_utf_char = (c & 0x0f);
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} else if ((c & 0xf8) == 0xf0) {
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vc->vc_utf_count = 3;
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vc->vc_utf_char = (c & 0x07);
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} else if ((c & 0xfc) == 0xf8) {
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vc->vc_utf_count = 4;
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vc->vc_utf_char = (c & 0x03);
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} else if ((c & 0xfe) == 0xfc) {
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vc->vc_utf_count = 5;
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vc->vc_utf_char = (c & 0x01);
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} else {
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/* 254 and 255 are invalid */
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return 0xfffd;
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}
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if (vc->vc_utf_count) {
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/* Still need some bytes */
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return -1;
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}
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}
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/* Nothing to do if an ASCII byte was received */
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}
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/* End of UTF-8 decoding. */
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/* c is the received character, or U+FFFD for invalid sequences. */
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/* Replace invalid Unicode code points with U+FFFD too */
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if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
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return 0xfffd;
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return c;
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vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
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vc->vc_npar++;
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if (--vc->vc_utf_count)
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goto need_more_bytes;
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/* Got a whole character */
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c = vc->vc_utf_char;
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/* Reject overlong sequences */
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if (c <= utf8_length_changes[vc->vc_npar - 1] ||
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c > utf8_length_changes[vc->vc_npar])
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return 0xfffd;
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return vc_sanitize_unicode(c);
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}
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/* Single ASCII byte or first byte of a sequence received */
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if (vc->vc_utf_count) {
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/* Continuation byte expected */
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*rescan = true;
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vc->vc_utf_count = 0;
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return 0xfffd;
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}
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/* Nothing to do if an ASCII byte was received */
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if (c <= 0x7f)
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return c;
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/* First byte of a multibyte sequence received */
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vc->vc_npar = 0;
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if ((c & 0xe0) == 0xc0) {
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vc->vc_utf_count = 1;
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vc->vc_utf_char = (c & 0x1f);
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} else if ((c & 0xf0) == 0xe0) {
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vc->vc_utf_count = 2;
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vc->vc_utf_char = (c & 0x0f);
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} else if ((c & 0xf8) == 0xf0) {
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vc->vc_utf_count = 3;
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vc->vc_utf_char = (c & 0x07);
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} else if ((c & 0xfc) == 0xf8) {
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vc->vc_utf_count = 4;
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vc->vc_utf_char = (c & 0x03);
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} else if ((c & 0xfe) == 0xfc) {
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vc->vc_utf_count = 5;
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vc->vc_utf_char = (c & 0x01);
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} else {
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/* 254 and 255 are invalid */
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return 0xfffd;
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}
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need_more_bytes:
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return -1;
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}
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/* acquires console_lock */
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