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, 6 insertions, 3 deletions

diff --git a/tests/testsuite.at b/tests/testsuite.at
index a1a563d..cbb12d4 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -394,6 +394,11 @@ TE_CHECK([[0EE 255@I/A/J 65001EE 0A-(-2)"N(0/0)' 1A-^^A"N(0/0)' 2A-(-1)"N(0/0)']
 TE_CHECK([[@EQa// 0EE 128@I/A/J 65001EE 0Qa-(-2)"N(0/0)' 1Qa-^^A"N(0/0)' 2Qa-(-1)"N(0/0)']], 0, ignore, ignore)
 AT_CLEANUP
 
+AT_SETUP([Glyphs to byte heuristics])
+# Should be fast.
+TE_CHECK([[100000<@I"Ж"> J<:C;> J<.-1:J;> .*2-^E"N(0/0)']], 0, ignore, ignore)
+AT_CLEANUP
+
 AT_SETUP([Automatic EOL normalization])
 TE_CHECK([[@EB'^EQ[$srcdir]/autoeol-input.txt' EL-2"N(0/0)' 2LR 13@I'' 0EL @EW'autoeol-sciteco.txt']],
          0, ignore, ignore)
@@ -542,9 +547,7 @@ AT_CLEANUP
 # It could fail because the memory limit is exceeed,
 # but not in this case since the match string isn't too large.
 AT_SETUP([Pattern matching overflow])
-# NOTE: Creating very long lines would currently be ineffective
-# at least in UTF-8 mode.
-TE_CHECK([[100000<@I"^J">J @S"^EM^X"]], 0, ignore, ignore)
+TE_CHECK([[100000<@I"X">J @S"^EM^X"]], 0, ignore, ignore)
 AT_CLEANUP
 
 AT_SETUP([Block-wise backwards search])