diff options
Diffstat (limited to 'generic/tkTextBTree.c')
| -rw-r--r-- | generic/tkTextBTree.c | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/generic/tkTextBTree.c b/generic/tkTextBTree.c index 005ce46..67ff79d 100644 --- a/generic/tkTextBTree.c +++ b/generic/tkTextBTree.c @@ -1991,17 +1991,37 @@ TkBTreeLinesTo( index += nodePtr2->numLines; } } - if (textPtr != NULL && textPtr->start != NULL) { - index -= TkBTreeLinesTo(NULL, textPtr->start); - if (index < 0) { - /* One should panic here! - Tcl_Panic("TkBTreeLinesTo: linePtr comes before -startline"); - */ + if (textPtr != NULL) { + /* + * The index to return must be relative to textPtr, not to the entire + * tree. Take care to never return a negative index when linePtr + * denotes a line before -startline, or an index larger than the + * number of lines in textPtr when linePtr is a line past -endline. + */ + + int indexStart, indexEnd; + + if (textPtr->start != NULL) { + indexStart = TkBTreeLinesTo(NULL, textPtr->start); + } else { + indexStart = 0; + } + if (textPtr->end != NULL) { + indexEnd = TkBTreeLinesTo(NULL, textPtr->end); + } else { + indexEnd = TkBTreeNumLines(textPtr->sharedTextPtr->tree, NULL); + } + if (index < indexStart) { + index = 0; + } else if (index > indexEnd) { + index = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr); + } else { + index -= indexStart; } } return index; } - + /* *---------------------------------------------------------------------- * |