rexy712/nano-with-linefolding
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

chars: probe for a valid UTF-8 starter byte, instead of overstepping

Browse Source 
Instead of always stepping back four bytes and then tentatively
moving forward again (which is wasteful when most codes are just
one or two bytes long), inspect the preceding bytes one by one
and begin the move forward at the first valid starter byte.

This reduces the backwards searching time by close to 40 percent.
This commit is contained in:
Benno Schulenberg
2017-05-02 13:05:58 +02:00
parent f162a6a2ab
commit 09cabcad5d
1 changed files with 14 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/chars.c
View File

@@ -383,8 +383,20 @@ size_t move_mbleft(const char *buf, size_t pos)
* possible point. */
if (pos < 4)
before = 0;
else
before = pos - 4;
else {
const char *ptr = buf + pos;
if ((signed char)*(--ptr) > -65)
before = pos - 1;
else if ((signed char)*(--ptr) > -65)
before = pos - 2;
else if ((signed char)*(--ptr) > -65)
before = pos - 3;
else if ((signed char)*(--ptr) > -65)
before = pos - 4;
else
before = pos - 1;
}
while (before < pos) {
char_len = parse_mbchar(buf + before, NULL, NULL);