revised and improved the Unicode glyph-to-byte conversion heuristics

Previously almost all glyph-to-byte offset conversions consulted
Scintilla's line index and counted characters on the resulting line.
For instance a simple expression like `.+1J` would scan the same line
twice completely, which would be very slow on pathologically long lines.
Even insertions did that due to having to update the ^Y ranges.
If you repeat such an operation over all characters as in `<.+1:J;>`
you would have complexity O(n^2) for n = line length.
Only commands with an explicit relative nature like `C` and `A` would
use teco_view_glyph2bytes_relative() which scans beginning at dot
as long as the relative movement is less than 1024 glyphs.

Wit the new heuristics almost all glyph-to-byte and byte-to-glyph
conversions can make use of that optimization.
This requires that dot must at all times be known in glyphs as well -
the byte position is managed by Scintilla (SCI_GETCURRENTPOS).
We therefore introduced teco_current_doc_set_dot() and
teco_current_doc_get_dot() to update dot in the current buffer or
Q-Register -- it cannot be stored along with the view since
Q-Registers share a single view.
A number of auxiliary functions have been introduced for
converting relative to a known (glyphs,bytes) offset pair
and for converting absolute and relative positions with regard
to the current doc and SCI_GETCURRENTPOS position.
Of course this is error-prone since the glyph and dot positions
are interdependant - they must always be kept in sync.

With these new optimizations even pathologically long lines can
(usually) be managed even in UTF-8 documents.
It does not address slow-downs in Scintilla's line layout, yet.
grosciteco.tes for instance runs twice as fast now.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/spawn.c b/src/spawn.c
index 0492bbf..b1cd305 100644
--- a/src/spawn.c
+++ b/src/spawn.c
@@ -222,8 +222,8 @@ teco_state_execute_initial(teco_machine_main_t *ctx, GError **error)
 
 	default:
 		/* pipe and replace character range */
-		teco_spawn_ctx.to = teco_interface_glyphs2bytes(teco_expressions_pop_num(0));
-		teco_spawn_ctx.from = teco_interface_glyphs2bytes(teco_expressions_pop_num(0));
+		teco_spawn_ctx.to = teco_interface_glyphs2bytes_absdot(teco_expressions_pop_num(0));
+		teco_spawn_ctx.from = teco_interface_glyphs2bytes_absdot(teco_expressions_pop_num(0));
 		rc = teco_bool(teco_spawn_ctx.from <= teco_spawn_ctx.to &&
 		               teco_spawn_ctx.from >= 0 && teco_spawn_ctx.to >= 0);
 	}
@@ -424,6 +424,8 @@ teco_state_execute_done(teco_machine_main_t *ctx, teco_string_t str, GError **er
 	g_source_attach(teco_spawn_ctx.stdout_src, teco_spawn_ctx.mainctx);
 
 	if (!teco_spawn_ctx.register_argument) {
+		teco_undo_int(teco_ranges[0].from) = teco_interface_bytes2glyphs_absdot(teco_spawn_ctx.from);
+
 		if (teco_current_doc_must_undo())
 			undo__teco_interface_ssm(SCI_GOTOPOS,
 			                         teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0), 0);
@@ -438,9 +440,12 @@ teco_state_execute_done(teco_machine_main_t *ctx, teco_string_t str, GError **er
 		                   teco_spawn_ctx.to - teco_spawn_ctx.from);
 
 		sptr_t pos = teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0);
-		teco_undo_int(teco_ranges[0].from) = teco_interface_bytes2glyphs(teco_spawn_ctx.from);
-		teco_undo_int(teco_ranges[0].to) = teco_interface_bytes2glyphs(pos);
+		teco_int_t to = teco_interface_bytes2glyphs_rel(teco_ranges[0].from, teco_spawn_ctx.from,
+		                                                pos - teco_spawn_ctx.from);
+		teco_undo_int(teco_ranges[0].to) = to;
 		teco_undo_guint(teco_ranges_count) = 1;
+
+		teco_current_doc_set_dot(to);
 	}
 	teco_interface_ssm(SCI_ENDUNDOACTION, 0, 0);