Move part of scanner.* into scanner-base.* for reuse in preparser scanner.

src/scanner-base.cc

Index: src/scanner-base.cc
diff --git a/src/scanner-base.cc b/src/scanner-base.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6e9d40e0d19a96b330038acccc79e98d970a0c23
--- /dev/null
+++ b/src/scanner-base.cc
@@ -0,0 +1,167 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Features shared by parsing and pre-parsing scanners.
+
+#include "scanner-base.h"
+
+namespace v8 {
+namespace internal {
+
+// ----------------------------------------------------------------------------
+// Keyword Matcher
+
+KeywordMatcher::FirstState KeywordMatcher::first_states_[] = {
+  { "break",  KEYWORD_PREFIX, Token::BREAK },
+  { NULL,     C,              Token::ILLEGAL },
+  { NULL,     D,              Token::ILLEGAL },
+  { "else",   KEYWORD_PREFIX, Token::ELSE },
+  { NULL,     F,              Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     I,              Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     N,              Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { "return", KEYWORD_PREFIX, Token::RETURN },
+  { "switch", KEYWORD_PREFIX, Token::SWITCH },
+  { NULL,     T,              Token::ILLEGAL },
+  { NULL,     UNMATCHABLE,    Token::ILLEGAL },
+  { NULL,     V,              Token::ILLEGAL },
+  { NULL,     W,              Token::ILLEGAL }
+};
+
+
+void KeywordMatcher::Step(unibrow::uchar input) {
+  switch (state_) {
+    case INITIAL: {
+      // matching the first character is the only state with significant fanout.
+      // Match only lower-case letters in range 'b'..'w'.
+      unsigned int offset = input - kFirstCharRangeMin;
+      if (offset < kFirstCharRangeLength) {
+        state_ = first_states_[offset].state;
+        if (state_ == KEYWORD_PREFIX) {
+          keyword_ = first_states_[offset].keyword;
+          counter_ = 1;
+          keyword_token_ = first_states_[offset].token;
+        }
+        return;
+      }
+      break;
+    }
+    case KEYWORD_PREFIX:
+      if (static_cast<unibrow::uchar>(keyword_[counter_]) == input) {
+        counter_++;
+        if (keyword_[counter_] == '\0') {
+          state_ = KEYWORD_MATCHED;
+          token_ = keyword_token_;
+        }
+        return;
+      }
+      break;
+    case KEYWORD_MATCHED:
+      token_ = Token::IDENTIFIER;
+      break;
+    case C:
+      if (MatchState(input, 'a', CA)) return;
+      if (MatchState(input, 'o', CO)) return;
+      break;
+    case CA:
+      if (MatchKeywordStart(input, "case", 2, Token::CASE)) return;
+      if (MatchKeywordStart(input, "catch", 2, Token::CATCH)) return;
+      break;
+    case CO:
+      if (MatchState(input, 'n', CON)) return;
+      break;
+    case CON:
+      if (MatchKeywordStart(input, "const", 3, Token::CONST)) return;
+      if (MatchKeywordStart(input, "continue", 3, Token::CONTINUE)) return;
+      break;
+    case D:
+      if (MatchState(input, 'e', DE)) return;
+      if (MatchKeyword(input, 'o', KEYWORD_MATCHED, Token::DO)) return;
+      break;
+    case DE:
+      if (MatchKeywordStart(input, "debugger", 2, Token::DEBUGGER)) return;
+      if (MatchKeywordStart(input, "default", 2, Token::DEFAULT)) return;
+      if (MatchKeywordStart(input, "delete", 2, Token::DELETE)) return;
+      break;
+    case F:
+      if (MatchKeywordStart(input, "false", 1, Token::FALSE_LITERAL)) return;
+      if (MatchKeywordStart(input, "finally", 1, Token::FINALLY)) return;
+      if (MatchKeywordStart(input, "for", 1, Token::FOR)) return;
+      if (MatchKeywordStart(input, "function", 1, Token::FUNCTION)) return;
+      break;
+    case I:
+      if (MatchKeyword(input, 'f', KEYWORD_MATCHED, Token::IF)) return;
+      if (MatchKeyword(input, 'n', IN, Token::IN)) return;
+      break;
+    case IN:
+      token_ = Token::IDENTIFIER;
+      if (MatchKeywordStart(input, "instanceof", 2, Token::INSTANCEOF)) {
+        return;
+      }
+      break;
+    case N:
+      if (MatchKeywordStart(input, "native", 1, Token::NATIVE)) return;
+      if (MatchKeywordStart(input, "new", 1, Token::NEW)) return;
+      if (MatchKeywordStart(input, "null", 1, Token::NULL_LITERAL)) return;
+      break;
+    case T:
+      if (MatchState(input, 'h', TH)) return;
+      if (MatchState(input, 'r', TR)) return;
+      if (MatchKeywordStart(input, "typeof", 1, Token::TYPEOF)) return;
+      break;
+    case TH:
+      if (MatchKeywordStart(input, "this", 2, Token::THIS)) return;
+      if (MatchKeywordStart(input, "throw", 2, Token::THROW)) return;
+      break;
+    case TR:
+      if (MatchKeywordStart(input, "true", 2, Token::TRUE_LITERAL)) return;
+      if (MatchKeyword(input, 'y', KEYWORD_MATCHED, Token::TRY)) return;
+      break;
+    case V:
+      if (MatchKeywordStart(input, "var", 1, Token::VAR)) return;
+      if (MatchKeywordStart(input, "void", 1, Token::VOID)) return;
+      break;
+    case W:
+      if (MatchKeywordStart(input, "while", 1, Token::WHILE)) return;
+      if (MatchKeywordStart(input, "with", 1, Token::WITH)) return;
+      break;
+    case UNMATCHABLE:
+      break;
+  }
+  // On fallthrough, it's a failure.
+  state_ = UNMATCHABLE;
+}
+
+} }  // namespace v8::internal