diff options
Diffstat (limited to 'deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/tree/IterativeParseTreeWalker.cpp')
-rw-r--r-- | deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/tree/IterativeParseTreeWalker.cpp | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/tree/IterativeParseTreeWalker.cpp b/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/tree/IterativeParseTreeWalker.cpp new file mode 100644 index 0000000000..66cfc91d1d --- /dev/null +++ b/deps/v8/third_party/antlr4/runtime/Cpp/runtime/src/tree/IterativeParseTreeWalker.cpp @@ -0,0 +1,71 @@ +/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved. + * Use of this file is governed by the BSD 3-clause license that + * can be found in the LICENSE.txt file in the project root. + */ + +#include "support/CPPUtils.h" + +#include "tree/ErrorNode.h" +#include "tree/ParseTree.h" +#include "tree/ParseTreeListener.h" + +#include "IterativeParseTreeWalker.h" + +using namespace antlr4::tree; + +void IterativeParseTreeWalker::walk(ParseTreeListener* listener, + ParseTree* t) const { + std::vector<ParseTree*> nodeStack; + std::vector<size_t> indexStack; + + ParseTree* currentNode = t; + size_t currentIndex = 0; + + while (currentNode != nullptr) { + // pre-order visit + if (antlrcpp::is<ErrorNode*>(currentNode)) { + listener->visitErrorNode(dynamic_cast<ErrorNode*>(currentNode)); + } else if (antlrcpp::is<TerminalNode*>(currentNode)) { + listener->visitTerminal((TerminalNode*)currentNode); + } else { + enterRule(listener, currentNode); + } + + // Move down to first child, if it exists. + if (!currentNode->children.empty()) { + nodeStack.push_back(currentNode); + indexStack.push_back(currentIndex); + currentIndex = 0; + currentNode = currentNode->children[0]; + continue; + } + + // No child nodes, so walk tree. + do { + // post-order visit + if (!antlrcpp::is<TerminalNode*>(currentNode)) { + exitRule(listener, currentNode); + } + + // No parent, so no siblings. + if (nodeStack.empty()) { + currentNode = nullptr; + currentIndex = 0; + break; + } + + // Move to next sibling if possible. + if (nodeStack.back()->children.size() > ++currentIndex) { + currentNode = nodeStack.back()->children[currentIndex]; + break; + } + + // No next sibling, so move up. + currentNode = nodeStack.back(); + nodeStack.pop_back(); + currentIndex = indexStack.back(); + indexStack.pop_back(); + + } while (currentNode != nullptr); + } +} |