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authorfvogel <fvogelnew1@free.fr>2016-07-05 20:02:59 (GMT)
committerfvogel <fvogelnew1@free.fr>2016-07-05 20:02:59 (GMT)
commit19daddfc9fecac5b38d749263e8553bc9b44d415 (patch)
treebefa80ab2fcb9d29bd43da212fdcc7d90cde6def
parent77f4d07ef5cfb838fee58aeadf50fa3d948d273d (diff)
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Better comments explaining the algorithm in ::tk::TextUndoRedoProcessMarks
-rw-r--r--library/text.tcl30
1 files changed, 23 insertions, 7 deletions
diff --git a/library/text.tcl b/library/text.tcl
index cc78bc2..f241abd 100644
--- a/library/text.tcl
+++ b/library/text.tcl
@@ -1217,13 +1217,17 @@ proc ::tk::TextScanDrag {w x y} {
proc ::tk::TextUndoRedoProcessMarks {w} {
set indices {}
set undoMarks {}
+
# only consider the temporary marks set by an undo/redo action
foreach mark [$w mark names] {
if {[string range $mark 0 11] eq "tk::undoMark"} {
lappend undoMarks $mark
}
}
- # the number of undo/redo marks is always even
+
+ # transform marks into indices
+ # the number of undo/redo marks is always even, each right mark
+ # completes a left mark to give a range
set nUndoMarks [llength $undoMarks]
set n [expr {$nUndoMarks / 2}]
set undoMarks [lsort -dictionary $undoMarks]
@@ -1233,39 +1237,51 @@ proc ::tk::TextUndoRedoProcessMarks {w} {
lappend indices [$w index $Lmark] [$w index $Rmark]
$w mark unset $Lmark $Rmark
}
-#puts "Unoptimized indices: $indices"
+
# process ranges to:
# - remove those already fully included in another range
# - merge overlapping ranges
set ind [lsort -dictionary -stride 2 $indices]
set indices {}
+
for {set i 0} {$i < $nUndoMarks} {incr i 2} {
set il1 [lindex $ind $i]
set ir1 [lindex $ind [expr {$i + 1}]]
lappend indices $il1 $ir1
-#puts " range1: $il1 $ir1"
+
for {set j [expr {$i + 2}]} {$j < $nUndoMarks} {incr j 2} {
set il2 [lindex $ind $j]
set ir2 [lindex $ind [expr {$j + 1}]]
-#puts " range2: $il2 $ir2"
+
if {[$w compare $il2 > $ir1]} {
# second range starts after the end of first range
+ # -> further second ranges do not need to be considered
+ # because ranges were sorted by increasing first index
set j $nUndoMarks
+
} else {
if {[$w compare $ir2 > $ir1]} {
- # second range overlaps with first range
+ # second range overlaps first range
+ # -> merge them into a single range
set indices [lreplace $indices end-1 end]
lappend indices $il1 $ir2
+
} else {
# second range is fully included in first range
+ # -> ignore it
+
}
+ # in both cases above, the second range shall be
+ # trimmed out from the list of ranges
set ind [lreplace $ind $j [expr {$j + 1}]]
incr j -2
incr nUndoMarks -2
+
}
-#puts " indices: $indices"
+
}
+
}
-#puts "OPTIMIZED indices: $indices"
+
return $indices
}