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, 2 insertions, 1 deletions

diff --git a/src/core-commands.h b/src/core-commands.h
index 254c4a7..6a31b92 100644
--- a/src/core-commands.h
+++ b/src/core-commands.h
@@ -29,7 +29,8 @@ teco_is_noop(gunichar c)
 	return c == ' ' || c == '\f' || c == '\r' || c == '\n' || c == '\v';
 }
 
-gboolean teco_get_range_args(const gchar *cmd, gsize *from_ret, gsize *len_ret, GError **error);
+gboolean teco_get_range_args(const gchar *cmd, teco_int_t *from_glyphs_ret, gsize *from_ret,
+                             teco_int_t *len_glyphs_ret, gsize *len_ret, GError **error);
 
 /* in cmdline.c */
 gboolean teco_state_command_process_edit_cmd(teco_machine_main_t *ctx, teco_machine_t *parent_ctx,