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, 15 insertions, 4 deletions

diff --git a/src/qreg-commands.c b/src/qreg-commands.c
index 4ede403..a31fe4c 100644
--- a/src/qreg-commands.c
+++ b/src/qreg-commands.c
@@ -572,9 +572,11 @@ teco_state_getqregstring_got_register(teco_machine_main_t *ctx, teco_qreg_t *qre
 			undo__teco_interface_ssm(SCI_UNDO, 0, 0);
 	}
 
-	teco_undo_int(teco_ranges[0].from) = teco_interface_bytes2glyphs(pos);
-	teco_undo_int(teco_ranges[0].to) = teco_interface_bytes2glyphs(pos + str.len);
+	teco_undo_int(teco_ranges[0].from) = teco_current_doc_get_dot();
+	teco_int_t to = teco_interface_bytes2glyphs_rel(teco_ranges[0].from, pos, str.len);
+	teco_undo_int(teco_ranges[0].to) = to;
 	teco_undo_guint(teco_ranges_count) = 1;
+	teco_current_doc_set_dot(to);
 
 	return &teco_state_start;
 }
@@ -798,9 +800,10 @@ teco_state_copytoqreg_got_register(teco_machine_main_t *ctx, teco_qreg_t *qreg,
 	if (ctx->flags.mode > TECO_MODE_NORMAL)
 		return &teco_state_start;
 
+	teco_int_t from_glyphs, len_glyphs;
 	gsize from, len;
 
-	if (!teco_get_range_args("X", &from, &len, error))
+	if (!teco_get_range_args("X", &from_glyphs, &from, &len_glyphs, &len, error))
 		return NULL;
 
 	/*
@@ -829,11 +832,12 @@ teco_state_copytoqreg_got_register(teco_machine_main_t *ctx, teco_qreg_t *qreg,
 	if (!modifier_at || len == 0)
 		return &teco_state_start;
 
+	sptr_t pos = teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0);
+
 	/*
 	 * If @-modified, cut into the register
 	 */
 	if (teco_current_doc_must_undo()) {
-		sptr_t pos = teco_interface_ssm(SCI_GETCURRENTPOS, 0, 0);
 		undo__teco_interface_ssm(SCI_GOTOPOS, pos, 0);
 		undo__teco_interface_ssm(SCI_UNDO, 0, 0);
 	}
@@ -846,6 +850,13 @@ teco_state_copytoqreg_got_register(teco_machine_main_t *ctx, teco_qreg_t *qreg,
 	teco_interface_ssm(SCI_ENDUNDOACTION, 0, 0);
 	teco_ring_dirtify();
 
+	if (from+len < pos)
+		/* dot after deleted range */
+		teco_current_doc_set_dot(teco_current_doc_get_dot() - len_glyphs);
+	else if (from <= pos)
+		/* dot falls on deleted range */
+		teco_current_doc_set_dot(from_glyphs);
+
 	return &teco_state_start;
 }