+static void getParagraphList(DocRange const & range,
+ ParagraphList & pars)
+{
+ // Clone the paragraphs within the selection.
+ pit_type startpit = range.from.pit();
+ pit_type endpit = range.to.pit();
+ ParagraphList const & ps_ = range.text()->paragraphs();
+ ParagraphList tmp_pars(boost::next(ps_.begin(), startpit),
+ boost::next(ps_.begin(), endpit + 1));
+
+ // Remove the end of the last paragraph; afterwards, remove the
+ // beginning of the first paragraph. Keep this order - there may only
+ // be one paragraph!
+ Paragraph & back = tmp_pars.back();
+ back.eraseChars(range.to.pos(), back.size(), false);
+ Paragraph & front = tmp_pars.front();
+ front.eraseChars(0, range.from.pos(), false);
+
+ pars.insert(pars.begin(), tmp_pars.begin(), tmp_pars.end());
+}
+
+
+static bool equal(Inset const * i_o, Inset const * i_n)
+{
+ if (!i_o || !i_n)
+ return false;
+
+ // Different types of insets
+ if (i_o->lyxCode() != i_n->lyxCode())
+ return false;
+
+ // Editable insets are assumed to be the same as they are of the
+ // same type. If we later on decide that we insert them in the
+ // document as being unchanged, we will run the algorithm on the
+ // contents of the two insets.
+ // FIXME: This fails if the parameters of the insets differ.
+ // FIXME: We do not recurse into InsetTabulars.
+ // FIXME: We need methods inset->equivalent(inset).
+ if (i_o->editable() && !i_o->asInsetMath()
+ && i_o->asInsetText())
+ return true;
+
+ ostringstream o_os;
+ ostringstream n_os;
+ i_o->write(o_os);
+ i_n->write(n_os);
+ return o_os.str() == n_os.str();
+}
+
+
+static bool equal(DocIterator & o, DocIterator & n) {
+ // Explicitly check for this, so we won't call
+ // Paragraph::getChar for the last pos.
+ bool const o_lastpos = o.pos() == o.lastpos();
+ bool const n_lastpos = n.pos() == n.lastpos();
+ if (o_lastpos || n_lastpos)
+ return o_lastpos && n_lastpos;
+
+ Paragraph const & old_par = o.text()->getPar(o.pit());
+ Paragraph const & new_par = n.text()->getPar(n.pit());
+
+ char_type const c_o = old_par.getChar(o.pos());
+ char_type const c_n = new_par.getChar(n.pos());
+ if (c_o != c_n)
+ return false;
+
+ if (old_par.isInset(o.pos())) {
+ Inset const * i_o = old_par.getInset(o.pos());
+ Inset const * i_n = new_par.getInset(n.pos());
+
+ if (i_o && i_n)
+ return equal(i_o, i_n);
+ }
+
+ Font fo = old_par.getFontSettings(o.buffer()->params(), o.pos());
+ Font fn = new_par.getFontSettings(n.buffer()->params(), n.pos());
+ return fo == fn;
+}
+
+
+/// Traverses a snake in a certain direction. p points to a
+/// position in the old and new file and they are synchronously
+/// moved along the snake. The function returns true if a snake
+/// was found.
+static bool traverseSnake(DocPair & p, DocRangePair const & range,
+ Direction direction)
+{
+ bool ret = false;
+ DocPair const & p_end =
+ direction == Forward ? range.to() : range.from();
+
+ while (p != p_end) {
+ if (direction == Backward)
+ --p;
+ if (!equal(p.o, p.n)) {
+ if (direction == Backward)
+ ++p;
+ return ret;
+ }
+ if (direction == Forward)
+ ++p;
+ ret = true;
+ }
+ return ret;
+}
+
+
+/////////////////////////////////////////////////////////////////////
+//
+// Compare::Impl
+//
+/////////////////////////////////////////////////////////////////////
+
+
+void Compare::Impl::furthestDpathKdiagonal(int D, int k,
+ DocRangePair const & rp, Direction direction)
+{
+ compl_vector<DocIterator> & op = direction == Forward ? ofp : orp;
+ compl_vector<DocIterator> & np = direction == Forward ? nfp : nrp;
+ compl_vector<DocIterator> & os = direction == Forward ? ofs : ors;
+ compl_vector<DocIterator> & ns = direction == Forward ? nfs : nrs;
+
+ // A vertical step means stepping one character in the new document.
+ bool vertical_step = k == -D;
+ if (!vertical_step && k != D) {
+ vertical_step = direction == Forward
+ ? op[k - 1] < op[k + 1] : op[k - 1] > op[k + 1];
+ }
+
+ // Where do we take the step from ?
+ int const kk = vertical_step ? k + 1 : k - 1;
+ DocPair p(op[kk], np[kk]);
+ DocPair const s(os[kk], ns[kk]);
+
+ // If D==0 we simulate a vertical step from (0,-1) by doing nothing.
+ if (D != 0) {
+ // Take a step
+ if (vertical_step && direction == Forward)
+ step(p.n, rp.n.to, direction);
+ else if (vertical_step && direction == Backward)
+ step(p.n, rp.n.from, direction);
+ else if (!vertical_step && direction == Forward)
+ step(p.o, rp.o.to, direction);
+ else if (!vertical_step && direction == Backward)
+ step(p.o, rp.o.from, direction);
+ }
+
+ // Traverse snake
+ if (traverseSnake(p, rp, direction)) {
+ // Record last snake
+ os[k] = p.o;
+ ns[k] = p.n;
+ } else {
+ // Copy last snake from the previous step
+ os[k] = s.o;
+ ns[k] = s.n;
+ }
+
+ //Record new position
+ op[k] = p.o;
+ np[k] = p.n;
+}
+
+
+bool Compare::Impl::overlap(int k, int D)
+{
+ // To generalize for the forward and reverse checks
+ int kk = offset_reverse_diagonal_ - k;
+
+ // Can we have overlap ?
+ if (kk <= D && kk >= -D) {
+ // Do we have overlap ?
+ if (odd_offset_)
+ return ofp[k] >= orp[kk] && nfp[k] >= nrp[kk];
+ else
+ return ofp[kk] >= orp[k] && nfp[kk] >= nrp[k];
+ }
+ return false;
+}
+
+
+Compare::Impl::SnakeResult Compare::Impl::retrieveMiddleSnake(
+ int k, int D, Direction direction, DocPair & middle_snake)
+{
+ compl_vector<DocIterator> & os = direction == Forward ? ofs : ors;
+ compl_vector<DocIterator> & ns = direction == Forward ? nfs : nrs;
+ compl_vector<DocIterator> & os_r = direction == Forward ? ors : ofs;
+ compl_vector<DocIterator> & ns_r = direction == Forward ? nrs : nfs;
+
+ // The diagonal while doing the backward search
+ int kk = -k + offset_reverse_diagonal_;
+
+ // Did we find a snake ?
+ if (os[k].empty() && os_r[kk].empty()) {
+ // No, there is no snake at all, in which case
+ // the length of the shortest edit script is M+N.
+ LASSERT(2 * D - odd_offset_ == M_ + N_, /**/);
+ return NoSnake;
+ }
+
+ if (os[k].empty()) {
+ // Yes, but there is only 1 snake and we found it in the
+ // reverse path.
+ middle_snake.o = os_r[kk];
+ middle_snake.n = ns_r[kk];
+ return SingleSnake;
+ }
+
+ middle_snake.o = os[k];
+ middle_snake.n = ns[k];
+ return NormalSnake;
+}
+
+
+int Compare::Impl::findMiddleSnake(DocRangePair const & rp,
+ DocPair & middle_snake)
+{
+ // The lengths of the old and new chunks.
+ N_ = rp.o.length();
+ M_ = rp.n.length();
+
+ // Forward paths are centered around the 0-diagonal; reverse paths
+ // are centered around the diagonal N - M. (Delta in the article)
+ offset_reverse_diagonal_ = N_ - M_;
+
+ // If the offset is odd, only check for overlap while extending forward
+ // paths, otherwise only check while extending reverse paths.
+ odd_offset_ = (offset_reverse_diagonal_ % 2 != 0);
+
+ ofp.reset(rp.o.from);
+ nfp.reset(rp.n.from);
+ ofs.reset(DocIterator());
+ nfs.reset(DocIterator());
+ orp.reset(rp.o.to);
+ nrp.reset(rp.n.to);
+ ors.reset(DocIterator());
+ nrs.reset(DocIterator());
+
+ // In the formula below, the "+ 1" ensures we round like ceil()
+ int const D_max = (M_ + N_ + 1)/2;
+ // D is the number of horizontal and vertical steps, i.e.
+ // different characters in the old and new chunk.
+ for (int D = 0; D <= D_max; ++D) {
+ // to be used in the status messages
+ D_ = D;
+
+ // Forward and reverse paths
+ for (int f = 0; f < 2; ++f) {
+ Direction direction = f == 0 ? Forward : Backward;
+
+ // Diagonals between -D and D can be reached by a D-path
+ for (int k = -D; k <= D; k += 2) {
+ // Find the furthest reaching D-path on this diagonal
+ furthestDpathKdiagonal(D, k, rp, direction);
+
+ // Only check for overlap for forward paths if the offset is odd
+ // and only for reverse paths if the offset is even.
+ if (odd_offset_ == (direction == Forward)) {
+
+ // Do the forward and backward paths overlap ?
+ if (overlap(k, D - odd_offset_)) {
+ retrieveMiddleSnake(k, D, direction, middle_snake);
+ return 2 * D - odd_offset_;
+ }
+ }
+ if (abort_)
+ return 0;
+ }
+ }
+ }
+ // This should never be reached
+ return -2;
+}
+
+
+bool Compare::Impl::diff(Buffer const * new_buf, Buffer const * old_buf,
+ Buffer const * dest_buf)
+{
+ if (!new_buf || !old_buf || !dest_buf)
+ return false;
+
+ old_buf_ = old_buf;
+ new_buf_ = new_buf;
+ dest_buf_ = dest_buf;
+ dest_pars_ = &dest_buf->inset().asInsetText()->paragraphs();
+ dest_pars_->clear();
+
+ recursion_level_ = 0;
+ nested_inset_level_ = 0;
+
+ DocRangePair rp(old_buf_, new_buf_);
+
+ DocPair from = rp.from();
+ traverseSnake(from, rp, Forward);
+ DocRangePair const snake(rp.from(), from);
+ processSnake(snake);
+
+ // Start the recursive algorithm
+ DocRangePair rp_new(from, rp.to());
+ if (!rp_new.o.empty() || !rp_new.n.empty())
+ diff_i(rp_new);
+
+ for (pit_type p = 0; p < (pit_type)dest_pars_->size(); ++p) {
+ (*dest_pars_)[p].setBuffer(const_cast<Buffer &>(*dest_buf));
+ (*dest_pars_)[p].setInsetOwner(&dest_buf_->inset());
+ }
+
+ return true;
+}
+
+
+void Compare::Impl::diff_i(DocRangePair const & rp)
+{
+ if (abort_)
+ return;
+
+ // The middle snake
+ DocPair middle_snake;
+
+ // Divides the problem into two smaller problems, split around
+ // the snake in the middle.
+ int const L_ses = findMiddleSnake(rp, middle_snake);
+
+ // Set maximum of progress bar
+ if (++recursion_level_ == 1)
+ compare_.progressMax(L_ses);
+
+ // There are now three possibilities: the strings were the same,
+ // the strings were completely different, or we found a middle
+ // snake and we can split the string into two parts to process.
+ if (L_ses == 0)
+ // Two the same strings (this must be a very rare case, because
+ // usually this will be part of a snake adjacent to these strings).
+ writeToDestBuffer(rp.o);
+
+ else if (middle_snake.o.empty()) {
+ // Two totally different strings
+ writeToDestBuffer(rp.o, Change::DELETED);
+ writeToDestBuffer(rp.n, Change::INSERTED);
+
+ } else {
+ // Retrieve the complete snake
+ DocPair first_part_end = middle_snake;
+ traverseSnake(first_part_end, rp, Backward);
+ DocRangePair first_part(rp.from(), first_part_end);
+
+ DocPair second_part_begin = middle_snake;
+ traverseSnake(second_part_begin, rp, Forward);
+ DocRangePair second_part(second_part_begin, rp.to());
+
+ // Split the string in three parts:
+ // 1. in front of the snake
+ diffPart(first_part);
+
+ // 2. the snake itself, and
+ DocRangePair const snake(first_part.to(), second_part.from());
+ processSnake(snake);
+
+ // 3. behind the snake.
+ diffPart(second_part);
+ }
+ --recursion_level_;
+}
+
+
+void Compare::Impl::diffPart(DocRangePair const & rp)
+{
+ // Is there a finite length string in both buffers, if not there
+ // is an empty string and we write the other one to the buffer.
+ if (!rp.o.empty() && !rp.n.empty())
+ diff_i(rp);
+
+ else if (!rp.o.empty())
+ writeToDestBuffer(rp.o, Change::DELETED);
+
+ else if (!rp.n.empty())
+ writeToDestBuffer(rp.n, Change::INSERTED);
+}
+
+
+void Compare::Impl::diffInset(Inset * inset, DocPair const & p)
+{
+ // Find the dociterators for the beginning and the
+ // end of the inset, for the old and new document.
+ DocRangePair const rp = stepIntoInset(p);
+
+ // Recurse into the inset. Temporarily replace the dest_pars
+ // paragraph list by the paragraph list of the nested inset.
+ ParagraphList * backup_dest_pars = dest_pars_;
+ dest_pars_ = &inset->asInsetText()->text().paragraphs();
+ dest_pars_->clear();
+
+ ++nested_inset_level_;
+ diff_i(rp);
+ --nested_inset_level_;
+
+ dest_pars_ = backup_dest_pars;
+}
+
+
+void Compare::Impl::processSnake(DocRangePair const & rp)
+{
+ ParagraphList pars;
+ getParagraphList(rp.o, pars);
+
+ // Find insets in this paragaph list
+ DocPair it = rp.from();
+ for (; it.o < rp.o.to; ++it) {
+ Inset * inset = it.o.text()->getPar(it.o.pit()).getInset(it.o.pos());
+ if (inset && inset->editable() && inset->asInsetText()) {
+ // Find the inset in the paragraph list that will be pasted into
+ // the final document. The contents of the inset will be replaced
+ // by the output of the algorithm below.
+ pit_type const pit = it.o.pit() - rp.o.from.pit();
+ pos_type const pos = pit ? it.o.pos() : it.o.pos() - rp.o.from.pos();
+ inset = pars[pit].getInset(pos);
+ LASSERT(inset, /**/);
+ diffInset(inset, it);
+ }
+ }
+ writeToDestBuffer(pars);
+}
+
+
+void Compare::Impl::writeToDestBuffer(DocRange const & range,
+ Change::Type type)
+{
+ ParagraphList pars;
+ getParagraphList(range, pars);
+
+ pos_type size = 0;
+
+ // Set the change
+ ParagraphList::iterator it = pars.begin();
+ for (; it != pars.end(); ++it) {
+ it->setChange(Change(type));
+ size += it->size();
+ }
+
+ writeToDestBuffer(pars);
+
+ if (nested_inset_level_ == 0)
+ compare_.progress(size);
+}
+
+
+void Compare::Impl::writeToDestBuffer(ParagraphList const & pars) const