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

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/CommonTokenStream.cpp b/antlr4-cpp-runtime-4.9.2-source/runtime/src/CommonTokenStream.cpp
new file mode 100644 (file)
index 0000000..7834296
--- /dev/null
+++ b/antlr4-cpp-runtime-4.9.2-source/runtime/src/CommonTokenStream.cpp
@@ -0,0 +1,78 @@
+/* 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 "Token.h"
+
+#include "CommonTokenStream.h"
+
+using namespace antlr4;
+
+CommonTokenStream::CommonTokenStream(TokenSource *tokenSource) : CommonTokenStream(tokenSource, Token::DEFAULT_CHANNEL) {
+}
+
+CommonTokenStream::CommonTokenStream(TokenSource *tokenSource, size_t channel_)
+: BufferedTokenStream(tokenSource), channel(channel_) {
+}
+
+ssize_t CommonTokenStream::adjustSeekIndex(size_t i) {
+  return nextTokenOnChannel(i, channel);
+}
+
+Token* CommonTokenStream::LB(size_t k) {
+  if (k == 0 || k > _p) {
+    return nullptr;
+  }
+
+  ssize_t i = static_cast<ssize_t>(_p);
+  size_t n = 1;
+  // find k good tokens looking backwards
+  while (n <= k) {
+    // skip off-channel tokens
+    i = previousTokenOnChannel(i - 1, channel);
+    n++;
+  }
+  if (i < 0) {
+    return nullptr;
+  }
+
+  return _tokens[i].get();
+}
+
+Token* CommonTokenStream::LT(ssize_t k) {
+  lazyInit();
+  if (k == 0) {
+    return nullptr;
+  }
+  if (k < 0) {
+    return LB(static_cast<size_t>(-k));
+  }
+  size_t i = _p;
+  ssize_t n = 1; // we know tokens[p] is a good one
+                 // find k good tokens
+  while (n < k) {
+    // skip off-channel tokens, but make sure to not look past EOF
+    if (sync(i + 1)) {
+      i = nextTokenOnChannel(i + 1, channel);
+    }
+    n++;
+  }
+
+  return _tokens[i].get();
+}
+
+int CommonTokenStream::getNumberOfOnChannelTokens() {
+  int n = 0;
+  fill();
+  for (size_t i = 0; i < _tokens.size(); i++) {
+    Token *t = _tokens[i].get();
+    if (t->getChannel() == channel) {
+      n++;
+    }
+    if (t->getType() == Token::EOF) {
+      break;
+    }
+  }
+  return n;
+}