Move V8 to external/v8

Change-Id: If68025d67453785a651c5dfb34fad298c16676a4

1 files changed, 975 insertions, 0 deletions

diff --git a/src/scanner.cc b/src/scanner.cc
new file mode 100644
index 00000000..3dae414f
--- /dev/null
+++ b/src/scanner.cc
@@ -0,0 +1,975 @@
+// Copyright 2006-2008 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.
+
+#include "v8.h"
+
+#include "ast.h"
+#include "scanner.h"
+
+namespace v8 {
+namespace internal {
+
+// ----------------------------------------------------------------------------
+// Character predicates
+
+
+unibrow::Predicate<IdentifierStart, 128> Scanner::kIsIdentifierStart;
+unibrow::Predicate<IdentifierPart, 128> Scanner::kIsIdentifierPart;
+unibrow::Predicate<unibrow::LineTerminator, 128> Scanner::kIsLineTerminator;
+unibrow::Predicate<unibrow::WhiteSpace, 128> Scanner::kIsWhiteSpace;
+
+
+StaticResource<Scanner::Utf8Decoder> Scanner::utf8_decoder_;
+
+
+// ----------------------------------------------------------------------------
+// UTF8Buffer
+
+UTF8Buffer::UTF8Buffer() {
+  static const int kInitialCapacity = 1 * KB;
+  data_ = NewArray<char>(kInitialCapacity);
+  limit_ = ComputeLimit(data_, kInitialCapacity);
+  Reset();
+  ASSERT(Capacity() == kInitialCapacity && pos() == 0);
+}
+
+
+UTF8Buffer::~UTF8Buffer() {
+  DeleteArray(data_);
+}
+
+
+void UTF8Buffer::AddCharSlow(uc32 c) {
+  static const int kCapacityGrowthLimit = 1 * MB;
+  if (cursor_ > limit_) {
+    int old_capacity = Capacity();
+    int old_position = pos();
+    int new_capacity =
+        Min(old_capacity * 2, old_capacity + kCapacityGrowthLimit);
+    char* new_data = NewArray<char>(new_capacity);
+    memcpy(new_data, data_, old_position);
+    DeleteArray(data_);
+    data_ = new_data;
+    cursor_ = new_data + old_position;
+    limit_ = ComputeLimit(new_data, new_capacity);
+    ASSERT(Capacity() == new_capacity && pos() == old_position);
+  }
+  if (static_cast<unsigned>(c) <= unibrow::Utf8::kMaxOneByteChar) {
+    *cursor_++ = c;  // Common case: 7-bit ASCII.
+  } else {
+    cursor_ += unibrow::Utf8::Encode(cursor_, c);
+  }
+  ASSERT(pos() <= Capacity());
+}
+
+
+// ----------------------------------------------------------------------------
+// UTF16Buffer
+
+
+UTF16Buffer::UTF16Buffer()
+    : pos_(0), size_(0) { }
+
+
+Handle<String> UTF16Buffer::SubString(int start, int end) {
+  return internal::SubString(data_, start, end);
+}
+
+
+// CharacterStreamUTF16Buffer
+CharacterStreamUTF16Buffer::CharacterStreamUTF16Buffer()
+    : pushback_buffer_(0), last_(0), stream_(NULL) { }
+
+
+void CharacterStreamUTF16Buffer::Initialize(Handle<String> data,
+                                            unibrow::CharacterStream* input) {
+  data_ = data;
+  pos_ = 0;
+  stream_ = input;
+}
+
+
+void CharacterStreamUTF16Buffer::PushBack(uc32 ch) {
+  pushback_buffer()->Add(last_);
+  last_ = ch;
+  pos_--;
+}
+
+
+uc32 CharacterStreamUTF16Buffer::Advance() {
+  // NOTE: It is of importance to Persian / Farsi resources that we do
+  // *not* strip format control characters in the scanner; see
+  //
+  //    https://bugzilla.mozilla.org/show_bug.cgi?id=274152
+  //
+  // So, even though ECMA-262, section 7.1, page 11, dictates that we
+  // must remove Unicode format-control characters, we do not. This is
+  // in line with how IE and SpiderMonkey handles it.
+  if (!pushback_buffer()->is_empty()) {
+    pos_++;
+    return last_ = pushback_buffer()->RemoveLast();
+  } else if (stream_->has_more()) {
+    pos_++;
+    uc32 next = stream_->GetNext();
+    return last_ = next;
+  } else {
+    // Note: currently the following increment is necessary to avoid a
+    // test-parser problem!
+    pos_++;
+    return last_ = static_cast<uc32>(-1);
+  }
+}
+
+
+void CharacterStreamUTF16Buffer::SeekForward(int pos) {
+  pos_ = pos;
+  ASSERT(pushback_buffer()->is_empty());
+  stream_->Seek(pos);
+}
+
+
+// TwoByteStringUTF16Buffer
+TwoByteStringUTF16Buffer::TwoByteStringUTF16Buffer()
+    : raw_data_(NULL) { }
+
+
+void TwoByteStringUTF16Buffer::Initialize(
+     Handle<ExternalTwoByteString> data) {
+  ASSERT(!data.is_null());
+
+  data_ = data;
+  pos_ = 0;
+
+  raw_data_ = data->resource()->data();
+  size_ = data->length();
+}
+
+
+uc32 TwoByteStringUTF16Buffer::Advance() {
+  if (pos_ < size_) {
+    return raw_data_[pos_++];
+  } else {
+    // note: currently the following increment is necessary to avoid a
+    // test-parser problem!
+    pos_++;
+    return static_cast<uc32>(-1);
+  }
+}
+
+
+void TwoByteStringUTF16Buffer::PushBack(uc32 ch) {
+  pos_--;
+  ASSERT(pos_ >= Scanner::kCharacterLookaheadBufferSize);
+  ASSERT(raw_data_[pos_ - Scanner::kCharacterLookaheadBufferSize] == ch);
+}
+
+
+void TwoByteStringUTF16Buffer::SeekForward(int pos) {
+  pos_ = pos;
+}
+
+
+// ----------------------------------------------------------------------------
+// Scanner
+
+Scanner::Scanner(bool pre) : stack_overflow_(false), is_pre_parsing_(pre) {
+  Token::Initialize();
+}
+
+
+void Scanner::Init(Handle<String> source, unibrow::CharacterStream* stream,
+    int position) {
+  // Initialize the source buffer.
+  if (!source.is_null() && StringShape(*source).IsExternalTwoByte()) {
+    two_byte_string_buffer_.Initialize(
+        Handle<ExternalTwoByteString>::cast(source));
+    source_ = &two_byte_string_buffer_;
+  } else {
+    char_stream_buffer_.Initialize(source, stream);
+    source_ = &char_stream_buffer_;
+  }
+
+  position_ = position;
+
+  // Reset literals buffer
+  literals_.Reset();
+
+  // Set c0_ (one character ahead)
+  ASSERT(kCharacterLookaheadBufferSize == 1);
+  Advance();
+
+  // Skip initial whitespace allowing HTML comment ends just like
+  // after a newline and scan first token.
+  has_line_terminator_before_next_ = true;
+  SkipWhiteSpace();
+  Scan();
+}
+
+
+Handle<String> Scanner::SubString(int start, int end) {
+  return source_->SubString(start - position_, end - position_);
+}
+
+
+Token::Value Scanner::Next() {
+  // BUG 1215673: Find a thread safe way to set a stack limit in
+  // pre-parse mode. Otherwise, we cannot safely pre-parse from other
+  // threads.
+  current_ = next_;
+  // Check for stack-overflow before returning any tokens.
+  StackLimitCheck check;
+  if (check.HasOverflowed()) {
+    stack_overflow_ = true;
+    next_.token = Token::ILLEGAL;
+  } else {
+    Scan();
+  }
+  return current_.token;
+}
+
+
+void Scanner::StartLiteral() {
+  next_.literal_pos = literals_.pos();
+}
+
+
+void Scanner::AddChar(uc32 c) {
+  literals_.AddChar(c);
+}
+
+
+void Scanner::TerminateLiteral() {
+  next_.literal_end = literals_.pos();
+  AddChar(0);
+}
+
+
+void Scanner::AddCharAdvance() {
+  AddChar(c0_);
+  Advance();
+}
+
+
+static inline bool IsByteOrderMark(uc32 c) {
+  // The Unicode value U+FFFE is guaranteed never to be assigned as a
+  // Unicode character; this implies that in a Unicode context the
+  // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF
+  // character expressed in little-endian byte order (since it could
+  // not be a U+FFFE character expressed in big-endian byte
+  // order). Nevertheless, we check for it to be compatible with
+  // Spidermonkey.
+  return c == 0xFEFF || c == 0xFFFE;
+}
+
+
+bool Scanner::SkipWhiteSpace() {
+  int start_position = source_pos();
+
+  while (true) {
+    // We treat byte-order marks (BOMs) as whitespace for better
+    // compatibility with Spidermonkey and other JavaScript engines.
+    while (kIsWhiteSpace.get(c0_) || IsByteOrderMark(c0_)) {
+      // IsWhiteSpace() includes line terminators!
+      if (kIsLineTerminator.get(c0_)) {
+        // Ignore line terminators, but remember them. This is necessary
+        // for automatic semicolon insertion.
+        has_line_terminator_before_next_ = true;
+      }
+      Advance();
+    }
+
+    // If there is an HTML comment end '-->' at the beginning of a
+    // line (with only whitespace in front of it), we treat the rest
+    // of the line as a comment. This is in line with the way
+    // SpiderMonkey handles it.
+    if (c0_ == '-' && has_line_terminator_before_next_) {
+      Advance();
+      if (c0_ == '-') {
+        Advance();
+        if (c0_ == '>') {
+          // Treat the rest of the line as a comment.
+          SkipSingleLineComment();
+          // Continue skipping white space after the comment.
+          continue;
+        }
+        PushBack('-');  // undo Advance()
+      }
+      PushBack('-');  // undo Advance()
+    }
+    // Return whether or not we skipped any characters.
+    return source_pos() != start_position;
+  }
+}
+
+
+Token::Value Scanner::SkipSingleLineComment() {
+  Advance();
+
+  // The line terminator at the end of the line is not considered
+  // to be part of the single-line comment; it is recognized
+  // separately by the lexical grammar and becomes part of the
+  // stream of input elements for the syntactic grammar (see
+  // ECMA-262, section 7.4, page 12).
+  while (c0_ >= 0 && !kIsLineTerminator.get(c0_)) {
+    Advance();
+  }
+
+  return Token::WHITESPACE;
+}
+
+
+Token::Value Scanner::SkipMultiLineComment() {
+  ASSERT(c0_ == '*');
+  Advance();
+
+  while (c0_ >= 0) {
+    char ch = c0_;
+    Advance();
+    // If we have reached the end of the multi-line comment, we
+    // consume the '/' and insert a whitespace. This way all
+    // multi-line comments are treated as whitespace - even the ones
+    // containing line terminators. This contradicts ECMA-262, section
+    // 7.4, page 12, that says that multi-line comments containing
+    // line terminators should be treated as a line terminator, but it
+    // matches the behaviour of SpiderMonkey and KJS.
+    if (ch == '*' && c0_ == '/') {
+      c0_ = ' ';
+      return Token::WHITESPACE;
+    }
+  }
+
+  // Unterminated multi-line comment.
+  return Token::ILLEGAL;
+}
+
+
+Token::Value Scanner::ScanHtmlComment() {
+  // Check for <!-- comments.
+  ASSERT(c0_ == '!');
+  Advance();
+  if (c0_ == '-') {
+    Advance();
+    if (c0_ == '-') return SkipSingleLineComment();
+    PushBack('-');  // undo Advance()
+  }
+  PushBack('!');  // undo Advance()
+  ASSERT(c0_ == '!');
+  return Token::LT;
+}
+
+
+void Scanner::Scan() {
+  Token::Value token;
+  has_line_terminator_before_next_ = false;
+  do {
+    // Remember the position of the next token
+    next_.location.beg_pos = source_pos();
+
+    switch (c0_) {
+      case ' ':
+      case '\t':
+        Advance();
+        token = Token::WHITESPACE;
+        break;
+
+      case '\n':
+        Advance();
+        has_line_terminator_before_next_ = true;
+        token = Token::WHITESPACE;
+        break;
+
+      case '"': case '\'':
+        token = ScanString();
+        break;
+
+      case '<':
+        // < <= << <<= <!--
+        Advance();
+        if (c0_ == '=') {
+          token = Select(Token::LTE);
+        } else if (c0_ == '<') {
+          token = Select('=', Token::ASSIGN_SHL, Token::SHL);
+        } else if (c0_ == '!') {
+          token = ScanHtmlComment();
+        } else {
+          token = Token::LT;
+        }
+        break;
+
+      case '>':
+        // > >= >> >>= >>> >>>=
+        Advance();
+        if (c0_ == '=') {
+          token = Select(Token::GTE);
+        } else if (c0_ == '>') {
+          // >> >>= >>> >>>=
+          Advance();
+          if (c0_ == '=') {
+            token = Select(Token::ASSIGN_SAR);
+          } else if (c0_ == '>') {
+            token = Select('=', Token::ASSIGN_SHR, Token::SHR);
+          } else {
+            token = Token::SAR;
+          }
+        } else {
+          token = Token::GT;
+        }
+        break;
+
+      case '=':
+        // = == ===
+        Advance();
+        if (c0_ == '=') {
+          token = Select('=', Token::EQ_STRICT, Token::EQ);
+        } else {
+          token = Token::ASSIGN;
+        }
+        break;
+
+      case '!':
+        // ! != !==
+        Advance();
+        if (c0_ == '=') {
+          token = Select('=', Token::NE_STRICT, Token::NE);
+        } else {
+          token = Token::NOT;
+        }
+        break;
+
+      case '+':
+        // + ++ +=
+        Advance();
+        if (c0_ == '+') {
+          token = Select(Token::INC);
+        } else if (c0_ == '=') {
+          token = Select(Token::ASSIGN_ADD);
+        } else {
+          token = Token::ADD;
+        }
+        break;
+
+      case '-':
+        // - -- --> -=
+        Advance();
+        if (c0_ == '-') {
+          Advance();
+          if (c0_ == '>' && has_line_terminator_before_next_) {
+            // For compatibility with SpiderMonkey, we skip lines that
+            // start with an HTML comment end '-->'.
+            token = SkipSingleLineComment();
+          } else {
+            token = Token::DEC;
+          }
+        } else if (c0_ == '=') {
+          token = Select(Token::ASSIGN_SUB);
+        } else {
+          token = Token::SUB;
+        }
+        break;
+
+      case '*':
+        // * *=
+        token = Select('=', Token::ASSIGN_MUL, Token::MUL);
+        break;
+
+      case '%':
+        // % %=
+        token = Select('=', Token::ASSIGN_MOD, Token::MOD);
+        break;
+
+      case '/':
+        // /  // /* /=
+        Advance();
+        if (c0_ == '/') {
+          token = SkipSingleLineComment();
+        } else if (c0_ == '*') {
+          token = SkipMultiLineComment();
+        } else if (c0_ == '=') {
+          token = Select(Token::ASSIGN_DIV);
+        } else {
+          token = Token::DIV;
+        }
+        break;
+
+      case '&':
+        // & && &=
+        Advance();
+        if (c0_ == '&') {
+          token = Select(Token::AND);
+        } else if (c0_ == '=') {
+          token = Select(Token::ASSIGN_BIT_AND);
+        } else {
+          token = Token::BIT_AND;
+        }
+        break;
+
+      case '|':
+        // | || |=
+        Advance();
+        if (c0_ == '|') {
+          token = Select(Token::OR);
+        } else if (c0_ == '=') {
+          token = Select(Token::ASSIGN_BIT_OR);
+        } else {
+          token = Token::BIT_OR;
+        }
+        break;
+
+      case '^':
+        // ^ ^=
+        token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR);
+        break;
+
+      case '.':
+        // . Number
+        Advance();
+        if (IsDecimalDigit(c0_)) {
+          token = ScanNumber(true);
+        } else {
+          token = Token::PERIOD;
+        }
+        break;
+
+      case ':':
+        token = Select(Token::COLON);
+        break;
+
+      case ';':
+        token = Select(Token::SEMICOLON);
+        break;
+
+      case ',':
+        token = Select(Token::COMMA);
+        break;
+
+      case '(':
+        token = Select(Token::LPAREN);
+        break;
+
+      case ')':
+        token = Select(Token::RPAREN);
+        break;
+
+      case '[':
+        token = Select(Token::LBRACK);
+        break;
+
+      case ']':
+        token = Select(Token::RBRACK);
+        break;
+
+      case '{':
+        token = Select(Token::LBRACE);
+        break;
+
+      case '}':
+        token = Select(Token::RBRACE);
+        break;
+
+      case '?':
+        token = Select(Token::CONDITIONAL);
+        break;
+
+      case '~':
+        token = Select(Token::BIT_NOT);
+        break;
+
+      default:
+        if (kIsIdentifierStart.get(c0_)) {
+          token = ScanIdentifier();
+        } else if (IsDecimalDigit(c0_)) {
+          token = ScanNumber(false);
+        } else if (SkipWhiteSpace()) {
+          token = Token::WHITESPACE;
+        } else if (c0_ < 0) {
+          token = Token::EOS;
+        } else {
+          token = Select(Token::ILLEGAL);
+        }
+        break;
+    }
+
+    // Continue scanning for tokens as long as we're just skipping
+    // whitespace.
+  } while (token == Token::WHITESPACE);
+
+  next_.location.end_pos = source_pos();
+  next_.token = token;
+}
+
+
+void Scanner::SeekForward(int pos) {
+  source_->SeekForward(pos - 1);
+  Advance();
+  Scan();
+}
+
+
+uc32 Scanner::ScanHexEscape(uc32 c, int length) {
+  ASSERT(length <= 4);  // prevent overflow
+
+  uc32 digits[4];
+  uc32 x = 0;
+  for (int i = 0; i < length; i++) {
+    digits[i] = c0_;
+    int d = HexValue(c0_);
+    if (d < 0) {
+      // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes
+      // should be illegal, but other JS VMs just return the
+      // non-escaped version of the original character.
+
+      // Push back digits read, except the last one (in c0_).
+      for (int j = i-1; j >= 0; j--) {
+        PushBack(digits[j]);
+      }
+      // Notice: No handling of error - treat it as "\u"->"u".
+      return c;
+    }
+    x = x * 16 + d;
+    Advance();
+  }
+
+  return x;
+}
+
+
+// Octal escapes of the forms '\0xx' and '\xxx' are not a part of
+// ECMA-262. Other JS VMs support them.
+uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
+  uc32 x = c - '0';
+  for (int i = 0; i < length; i++) {
+    int d = c0_ - '0';
+    if (d < 0 || d > 7) break;
+    int nx = x * 8 + d;
+    if (nx >= 256) break;
+    x = nx;
+    Advance();
+  }
+  return x;
+}
+
+
+void Scanner::ScanEscape() {
+  uc32 c = c0_;
+  Advance();
+
+  // Skip escaped newlines.
+  if (kIsLineTerminator.get(c)) {
+    // Allow CR+LF newlines in multiline string literals.
+    if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance();
+    // Allow LF+CR newlines in multiline string literals.
+    if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance();
+    return;
+  }
+
+  switch (c) {
+    case '\'':  // fall through
+    case '"' :  // fall through
+    case '\\': break;
+    case 'b' : c = '\b'; break;
+    case 'f' : c = '\f'; break;
+    case 'n' : c = '\n'; break;
+    case 'r' : c = '\r'; break;
+    case 't' : c = '\t'; break;
+    case 'u' : c = ScanHexEscape(c, 4); break;
+    case 'v' : c = '\v'; break;
+    case 'x' : c = ScanHexEscape(c, 2); break;
+    case '0' :  // fall through
+    case '1' :  // fall through
+    case '2' :  // fall through
+    case '3' :  // fall through
+    case '4' :  // fall through
+    case '5' :  // fall through
+    case '6' :  // fall through
+    case '7' : c = ScanOctalEscape(c, 2); break;
+  }
+
+  // According to ECMA-262, 3rd, 7.8.4 (p 18ff) these
+  // should be illegal, but they are commonly handled
+  // as non-escaped characters by JS VMs.
+  AddChar(c);
+}
+
+
+Token::Value Scanner::ScanString() {
+  uc32 quote = c0_;
+  Advance();  // consume quote
+
+  StartLiteral();
+  while (c0_ != quote && c0_ >= 0 && !kIsLineTerminator.get(c0_)) {
+    uc32 c = c0_;
+    Advance();
+    if (c == '\\') {
+      if (c0_ < 0) return Token::ILLEGAL;
+      ScanEscape();
+    } else {
+      AddChar(c);
+    }
+  }
+  if (c0_ != quote) {
+    return Token::ILLEGAL;
+  }
+  TerminateLiteral();
+
+  Advance();  // consume quote
+  return Token::STRING;
+}
+
+
+Token::Value Scanner::Select(Token::Value tok) {
+  Advance();
+  return tok;
+}
+
+
+Token::Value Scanner::Select(uc32 next, Token::Value then, Token::Value else_) {
+  Advance();
+  if (c0_ == next) {
+    Advance();
+    return then;
+  } else {
+    return else_;
+  }
+}
+
+
+// Returns true if any decimal digits were scanned, returns false otherwise.
+void Scanner::ScanDecimalDigits() {
+  while (IsDecimalDigit(c0_))
+    AddCharAdvance();
+}
+
+
+Token::Value Scanner::ScanNumber(bool seen_period) {
+  ASSERT(IsDecimalDigit(c0_));  // the first digit of the number or the fraction
+
+  enum { DECIMAL, HEX, OCTAL } kind = DECIMAL;
+
+  StartLiteral();
+  if (seen_period) {
+    // we have already seen a decimal point of the float
+    AddChar('.');
+    ScanDecimalDigits();  // we know we have at least one digit
+
+  } else {
+    // if the first character is '0' we must check for octals and hex
+    if (c0_ == '0') {
+      AddCharAdvance();
+
+      // either 0, 0exxx, 0Exxx, 0.xxx, an octal number, or a hex number
+      if (c0_ == 'x' || c0_ == 'X') {
+        // hex number
+        kind = HEX;
+        AddCharAdvance();
+        if (!IsHexDigit(c0_))
+          // we must have at least one hex digit after 'x'/'X'
+          return Token::ILLEGAL;
+        while (IsHexDigit(c0_))
+          AddCharAdvance();
+
+      } else if ('0' <= c0_ && c0_ <= '7') {
+        // (possible) octal number
+        kind = OCTAL;
+        while (true) {
+          if (c0_ == '8' || c0_ == '9') {
+            kind = DECIMAL;
+            break;
+          }
+          if (c0_  < '0' || '7'  < c0_) break;
+          AddCharAdvance();
+        }
+      }
+    }
+
+    // Parse decimal digits and allow trailing fractional part.
+    if (kind == DECIMAL) {
+      ScanDecimalDigits();  // optional
+      if (c0_ == '.') {
+        AddCharAdvance();
+        ScanDecimalDigits();  // optional
+      }
+    }
+  }
+
+  // scan exponent, if any
+  if (c0_ == 'e' || c0_ == 'E') {
+    ASSERT(kind != HEX);  // 'e'/'E' must be scanned as part of the hex number
+    if (kind == OCTAL) return Token::ILLEGAL;  // no exponent for octals allowed
+    // scan exponent
+    AddCharAdvance();
+    if (c0_ == '+' || c0_ == '-')
+      AddCharAdvance();
+    if (!IsDecimalDigit(c0_))
+      // we must have at least one decimal digit after 'e'/'E'
+      return Token::ILLEGAL;
+    ScanDecimalDigits();
+  }
+  TerminateLiteral();
+
+  // The source character immediately following a numeric literal must
+  // not be an identifier start or a decimal digit; see ECMA-262
+  // section 7.8.3, page 17 (note that we read only one decimal digit
+  // if the value is 0).
+  if (IsDecimalDigit(c0_) || kIsIdentifierStart.get(c0_))
+    return Token::ILLEGAL;
+
+  return Token::NUMBER;
+}
+
+
+uc32 Scanner::ScanIdentifierUnicodeEscape() {
+  Advance();
+  if (c0_ != 'u') return unibrow::Utf8::kBadChar;
+  Advance();
+  uc32 c = ScanHexEscape('u', 4);
+  // We do not allow a unicode escape sequence to start another
+  // unicode escape sequence.
+  if (c == '\\') return unibrow::Utf8::kBadChar;
+  return c;
+}
+
+
+Token::Value Scanner::ScanIdentifier() {
+  ASSERT(kIsIdentifierStart.get(c0_));
+  bool has_escapes = false;
+
+  StartLiteral();
+  // Scan identifier start character.
+  if (c0_ == '\\') {
+    has_escapes = true;
+    uc32 c = ScanIdentifierUnicodeEscape();
+    // Only allow legal identifier start characters.
+    if (!kIsIdentifierStart.get(c)) return Token::ILLEGAL;
+    AddChar(c);
+  } else {
+    AddChar(c0_);
+    Advance();
+  }
+
+  // Scan the rest of the identifier characters.
+  while (kIsIdentifierPart.get(c0_)) {
+    if (c0_ == '\\') {
+      has_escapes = true;
+      uc32 c = ScanIdentifierUnicodeEscape();
+      // Only allow legal identifier part characters.
+      if (!kIsIdentifierPart.get(c)) return Token::ILLEGAL;
+      AddChar(c);
+    } else {
+      AddChar(c0_);
+      Advance();
+    }
+  }
+  TerminateLiteral();
+
+  // We don't have any 1-letter keywords (this is probably a common case).
+  if ((next_.literal_end - next_.literal_pos) == 1) {
+    return Token::IDENTIFIER;
+  }
+
+  // If the identifier contains unicode escapes, it must not be
+  // resolved to a keyword.
+  if (has_escapes) {
+    return Token::IDENTIFIER;
+  }
+
+  return Token::Lookup(&literals_.data()[next_.literal_pos]);
+}
+
+
+
+bool Scanner::IsIdentifier(unibrow::CharacterStream* buffer) {
+  // Checks whether the buffer contains an identifier (no escape).
+  if (!buffer->has_more()) return false;
+  if (!kIsIdentifierStart.get(buffer->GetNext())) return false;
+  while (buffer->has_more()) {
+    if (!kIsIdentifierPart.get(buffer->GetNext())) return false;
+  }
+  return true;
+}
+
+
+bool Scanner::ScanRegExpPattern(bool seen_equal) {
+  // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags
+  bool in_character_class = false;
+
+  // Previous token is either '/' or '/=', in the second case, the
+  // pattern starts at =.
+  next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1);
+  next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0);
+
+  // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5,
+  // the scanner should pass uninterpreted bodies to the RegExp
+  // constructor.
+  StartLiteral();
+  if (seen_equal)
+    AddChar('=');
+
+  while (c0_ != '/' || in_character_class) {
+    if (kIsLineTerminator.get(c0_) || c0_ < 0)
+      return false;
+    if (c0_ == '\\') {  // escaped character
+      AddCharAdvance();
+      if (kIsLineTerminator.get(c0_) || c0_ < 0)
+        return false;
+      AddCharAdvance();
+    } else {  // unescaped character
+      if (c0_ == '[')
+        in_character_class = true;
+      if (c0_ == ']')
+        in_character_class = false;
+      AddCharAdvance();
+    }
+  }
+  Advance();  // consume '/'
+
+  TerminateLiteral();
+
+  return true;
+}
+
+bool Scanner::ScanRegExpFlags() {
+  // Scan regular expression flags.
+  StartLiteral();
+  while (kIsIdentifierPart.get(c0_)) {
+    if (c0_ == '\\') {
+      uc32 c = ScanIdentifierUnicodeEscape();
+      if (c != static_cast<uc32>(unibrow::Utf8::kBadChar)) {
+        // We allow any escaped character, unlike the restriction on
+        // IdentifierPart when it is used to build an IdentifierName.
+        AddChar(c);
+        continue;
+      }
+    }
+    AddCharAdvance();
+  }
+  TerminateLiteral();
+
+  next_.location.end_pos = source_pos() - 1;
+  return true;
+}
+
+} }  // namespace v8::internal