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| author | Gregory Heytings <gregory@heytings.org> | 2023-03-28 23:06:56 +0000 |
|---|---|---|
| committer | Gregory Heytings <gregory@heytings.org> | 2023-03-29 01:12:39 +0200 |
| commit | afc2c6c13cb2ebb50a6c31fca5552f9b98b4af95 (patch) | |
| tree | 762b7f83fd30c7a60355f8bacf890bf8c1674148 | |
| parent | 7e26a5c774e7c71782d89abe1d4be125d8422a4b (diff) | |
| download | emacs-afc2c6c13cb2ebb50a6c31fca5552f9b98b4af95.tar.gz | |
Improve accuracy of cursor motion commands in long lines
* src/xdisp.c (get_nearby_bol_pos): New function.
(get_small_narrowing_begv): Use it. This makes cursor motion
commands much more accurate in the first 500K characters of each
long line.
| -rw-r--r-- | src/xdisp.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/src/xdisp.c b/src/xdisp.c index c752f6712ab..454cbbbf6d5 100644 --- a/src/xdisp.c +++ b/src/xdisp.c @@ -3608,11 +3608,30 @@ get_medium_narrowing_zv (struct window *w, ptrdiff_t pos) return min ((pos / len + 1) * len, ZV); } +static ptrdiff_t +get_nearby_bol_pos (ptrdiff_t pos) +{ + ptrdiff_t start, pos_bytepos, cur, next, found, bol = 0; + start = pos - 500000 < BEGV ? BEGV : pos - 500000; + pos_bytepos = CHAR_TO_BYTE (pos); + for (cur = start; cur < pos; cur = next) + { + next = find_newline1 (cur, CHAR_TO_BYTE (cur), pos, pos_bytepos, + 1, &found, NULL, false); + if (found) + bol = next; + else + break; + } + return bol; +} + ptrdiff_t get_small_narrowing_begv (struct window *w, ptrdiff_t pos) { int len = get_narrowed_width (w); - return max ((pos / len - 1) * len, BEGV); + int bol_pos = get_nearby_bol_pos (pos); + return max (bol_pos + ((pos - bol_pos) / len - 1) * len, BEGV); } ptrdiff_t @@ -3653,7 +3672,7 @@ unwind_narrowed_begv (Lisp_Object point_min) #define SET_WITH_NARROWED_BEGV(IT,DST,EXPR,BV) \ do { \ - if (IT->medium_narrowing_begv) \ + if (IT->medium_narrowing_begv) \ { \ specpdl_ref count = SPECPDL_INDEX (); \ record_unwind_protect (unwind_narrowed_begv, Fpoint_min ()); \ |