add antlr source code and ReadMe

[toc] / antlr4-cpp-runtime-4.9.2-source / runtime / src / atn / SingletonPredictionContext.cpp

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/atn/SingletonPredictionContext.cpp b/antlr4-cpp-runtime-4.9.2-source/runtime/src/atn/SingletonPredictionContext.cpp
new file mode 100644 (file)
index 0000000..39ad9fb
--- /dev/null
+++ b/antlr4-cpp-runtime-4.9.2-source/runtime/src/atn/SingletonPredictionContext.cpp
@@ -0,0 +1,81 @@
+/* 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 "atn/EmptyPredictionContext.h"
+
+#include "atn/SingletonPredictionContext.h"
+
+using namespace antlr4::atn;
+
+SingletonPredictionContext::SingletonPredictionContext(Ref<PredictionContext> const& parent, size_t returnState)
+  : PredictionContext(parent ? calculateHashCode(parent, returnState) : calculateEmptyHashCode()),
+    parent(parent), returnState(returnState) {
+  assert(returnState != ATNState::INVALID_STATE_NUMBER);
+}
+
+SingletonPredictionContext::~SingletonPredictionContext() {
+}
+
+Ref<SingletonPredictionContext> SingletonPredictionContext::create(Ref<PredictionContext> const& parent, size_t returnState) {
+
+  if (returnState == EMPTY_RETURN_STATE && parent) {
+    // someone can pass in the bits of an array ctx that mean $
+    return std::dynamic_pointer_cast<SingletonPredictionContext>(EMPTY);
+  }
+  return std::make_shared<SingletonPredictionContext>(parent, returnState);
+}
+
+size_t SingletonPredictionContext::size() const {
+  return 1;
+}
+
+Ref<PredictionContext> SingletonPredictionContext::getParent(size_t index) const {
+  assert(index == 0);
+  ((void)(index)); // Make Release build happy.
+  return parent;
+}
+
+size_t SingletonPredictionContext::getReturnState(size_t index) const {
+  assert(index == 0);
+  ((void)(index)); // Make Release build happy.
+  return returnState;
+}
+
+bool SingletonPredictionContext::operator == (const PredictionContext &o) const {
+  if (this == &o) {
+    return true;
+  }
+
+  const SingletonPredictionContext *other = dynamic_cast<const SingletonPredictionContext*>(&o);
+  if (other == nullptr) {
+    return false;
+  }
+
+  if (this->hashCode() != other->hashCode()) {
+    return false; // can't be same if hash is different
+  }
+
+  if (returnState != other->returnState)
+    return false;
+
+  if (!parent && !other->parent)
+    return true;
+  if (!parent || !other->parent)
+    return false;
+
+   return *parent == *other->parent;
+}
+
+std::string SingletonPredictionContext::toString() const {
+  //std::string up = !parent.expired() ? parent.lock()->toString() : "";
+  std::string up = parent != nullptr ? parent->toString() : "";
+  if (up.length() == 0) {
+    if (returnState == EMPTY_RETURN_STATE) {
+      return "$";
+    }
+    return std::to_string(returnState);
+  }
+  return std::to_string(returnState) + " " + up;
+}