Fix UTF-8 auto alignment
diff --git a/expat/lib/xmltok.c b/expat/lib/xmltok.c
index 72058d3..4195279 100644
--- a/expat/lib/xmltok.c
+++ b/expat/lib/xmltok.c
@@ -333,9 +333,34 @@
align_limit_to_full_utf8_characters(const char * from, const char ** fromLimRef)
{
const char * fromLim = *fromLimRef;
- for (; fromLim > from; fromLim--)
- if (((unsigned char)fromLim[-1] & 0xc0) != 0x80)
+ size_t walked = 0;
+ for (; fromLim > from; fromLim--, walked++) {
+ const unsigned char prev = (unsigned char)fromLim[-1];
+ if ((prev & 0xf8u) == 0xf0u) { /* 4-byte character, lead by 0b11110xxx byte */
+ if (walked + 1 >= 4) {
+ fromLim += 4 - 1;
+ break;
+ } else {
+ walked = 0;
+ }
+ } else if ((prev & 0xf0u) == 0xe0u) { /* 3-byte character, lead by 0b1110xxxx byte */
+ if (walked + 1 >= 3) {
+ fromLim += 3 - 1;
+ break;
+ } else {
+ walked = 0;
+ }
+ } else if ((prev & 0xe0u) == 0xc0u) { /* 2-byte character, lead by 0b110xxxxx byte */
+ if (walked + 1 >= 2) {
+ fromLim += 2 - 1;
+ break;
+ } else {
+ walked = 0;
+ }
+ } else if ((prev & 0x80u) == 0x00u) { /* 1-byte character, matching 0b0xxxxxxx */
break;
+ }
+ }
*fromLimRef = fromLim;
}
