+//-----------------------------------------------------------------------------
+//
+// calcChainedFollowPos. Modify the previously calculated followPos sets
+// to implement rule chaining. NOT described by Aho
+//
+//-----------------------------------------------------------------------------
+void RBBITableBuilder::calcChainedFollowPos(RBBINode *tree) {
+
+ UVector endMarkerNodes(*fStatus);
+ UVector leafNodes(*fStatus);
+ int32_t i;
+
+ if (U_FAILURE(*fStatus)) {
+ return;
+ }
+
+ // get a list of all endmarker nodes.
+ tree->findNodes(&endMarkerNodes, RBBINode::endMark, *fStatus);
+
+ // get a list all leaf nodes
+ tree->findNodes(&leafNodes, RBBINode::leafChar, *fStatus);
+ if (U_FAILURE(*fStatus)) {
+ return;
+ }
+
+ // Get all nodes that can be the start a match, which is FirstPosition()
+ // of the portion of the tree corresponding to user-written rules.
+ // See the tree description in bofFixup().
+ RBBINode *userRuleRoot = tree;
+ if (fRB->fSetBuilder->sawBOF()) {
+ userRuleRoot = tree->fLeftChild->fRightChild;
+ }
+ U_ASSERT(userRuleRoot != NULL);
+ UVector *matchStartNodes = userRuleRoot->fFirstPosSet;
+
+
+ // Iteratate over all leaf nodes,
+ //
+ int32_t endNodeIx;
+ int32_t startNodeIx;
+
+ for (endNodeIx=0; endNodeIx<leafNodes.size(); endNodeIx++) {
+ RBBINode *tNode = (RBBINode *)leafNodes.elementAt(endNodeIx);
+ RBBINode *endNode = NULL;
+
+ // Identify leaf nodes that correspond to overall rule match positions.
+ // These include an endMarkerNode in their followPos sets.
+ for (i=0; i<endMarkerNodes.size(); i++) {
+ if (tNode->fFollowPos->contains(endMarkerNodes.elementAt(i))) {
+ endNode = tNode;
+ break;
+ }
+ }
+ if (endNode == NULL) {
+ // node wasn't an end node. Try again with the next.
+ continue;
+ }
+
+ // We've got a node that can end a match.
+
+ // Line Break Specific hack: If this node's val correspond to the $CM char class,
+ // don't chain from it.
+ // TODO: Add rule syntax for this behavior, get specifics out of here and
+ // into the rule file.
+ if (fRB->fLBCMNoChain || fRB->fRINoChain) {
+ UChar32 c = this->fRB->fSetBuilder->getFirstChar(endNode->fVal);
+ if (c != -1) {
+ // c == -1 occurs with sets containing only the {eof} marker string.
+ if (fRB->fLBCMNoChain) {
+ ULineBreak cLBProp = (ULineBreak)u_getIntPropertyValue(c, UCHAR_LINE_BREAK);
+ if (cLBProp == U_LB_COMBINING_MARK) {
+ continue;
+ }
+ }
+ if (fRB->fRINoChain) {
+ UGraphemeClusterBreak cGBProp = (UGraphemeClusterBreak)u_getIntPropertyValue(c, UCHAR_GRAPHEME_CLUSTER_BREAK);
+ if (cGBProp == U_GCB_REGIONAL_INDICATOR) {
+ continue;
+ }
+ }
+ }
+ }
+
+
+ // Now iterate over the nodes that can start a match, looking for ones
+ // with the same char class as our ending node.
+ RBBINode *startNode;
+ for (startNodeIx = 0; startNodeIx<matchStartNodes->size(); startNodeIx++) {
+ startNode = (RBBINode *)matchStartNodes->elementAt(startNodeIx);
+ if (startNode->fType != RBBINode::leafChar) {
+ continue;
+ }
+
+ if (endNode->fVal == startNode->fVal) {
+ // The end val (character class) of one possible match is the
+ // same as the start of another.
+
+ // Add all nodes from the followPos of the start node to the
+ // followPos set of the end node, which will have the effect of
+ // letting matches transition from a match state at endNode
+ // to the second char of a match starting with startNode.
+ setAdd(endNode->fFollowPos, startNode->fFollowPos);
+ }
+ }
+ }
+}
+
+
+//-----------------------------------------------------------------------------
+//
+// bofFixup. Fixup for state tables that include {bof} beginning of input testing.
+// Do an swizzle similar to chaining, modifying the followPos set of
+// the bofNode to include the followPos nodes from other {bot} nodes
+// scattered through the tree.
+//
+// This function has much in common with calcChainedFollowPos().
+//
+//-----------------------------------------------------------------------------
+void RBBITableBuilder::bofFixup() {
+
+ if (U_FAILURE(*fStatus)) {
+ return;
+ }
+
+ // The parse tree looks like this ...
+ // fTree root ---> <cat>
+ // / \ .
+ // <cat> <#end node>
+ // / \ .
+ // <bofNode> rest
+ // of tree
+ //
+ // We will be adding things to the followPos set of the <bofNode>
+ //
+ RBBINode *bofNode = fTree->fLeftChild->fLeftChild;
+ U_ASSERT(bofNode->fType == RBBINode::leafChar);
+ U_ASSERT(bofNode->fVal == 2);
+
+ // Get all nodes that can be the start a match of the user-written rules
+ // (excluding the fake bofNode)
+ // We want the nodes that can start a match in the
+ // part labeled "rest of tree"
+ //
+ UVector *matchStartNodes = fTree->fLeftChild->fRightChild->fFirstPosSet;
+
+ RBBINode *startNode;
+ int startNodeIx;
+ for (startNodeIx = 0; startNodeIx<matchStartNodes->size(); startNodeIx++) {
+ startNode = (RBBINode *)matchStartNodes->elementAt(startNodeIx);
+ if (startNode->fType != RBBINode::leafChar) {
+ continue;
+ }
+
+ if (startNode->fVal == bofNode->fVal) {
+ // We found a leaf node corresponding to a {bof} that was
+ // explicitly written into a rule.
+ // Add everything from the followPos set of this node to the
+ // followPos set of the fake bofNode at the start of the tree.
+ //
+ setAdd(bofNode->fFollowPos, startNode->fFollowPos);
+ }
+ }
+}
+
projects / apple / icu.git / blobdiff