Version 3.0.2.

src/preparser-api.cc

 // 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
@@ skipping 21 matching lines @@
 #include "utils.h"
 #include "list.h"
 #include "scanner-base.h"
 #include "preparse-data.h"
 #include "preparser.h"
 
 namespace v8 {
 namespace internal {
 
 // UTF16Buffer based on a v8::UnicodeInputStream.
-class InputStreamUTF16Buffer : public UC16CharacterStream {
+class InputStreamUTF16Buffer : public UTF16Buffer {
  public:
-  /* The InputStreamUTF16Buffer maintains an internal buffer
-   * that is filled in chunks from the UC16CharacterStream.
-   * It also maintains unlimited pushback capability, but optimized
-   * for small pushbacks.
-   * The pushback_buffer_ pointer points to the limit of pushbacks
-   * in the current buffer. There is room for a few pushback'ed chars before
-   * the buffer containing the most recently read chunk. If this is overflowed,
-   * an external buffer is allocated/reused to hold further pushbacks, and
-   * pushback_buffer_ and buffer_cursor_/buffer_end_ now points to the
-   * new buffer. When this buffer is read to the end again, the cursor is
-   * switched back to the internal buffer
-   */
-  explicit InputStreamUTF16Buffer(v8::UnicodeInputStream* stream)
-      : UC16CharacterStream(),
-        stream_(stream),
-        pushback_buffer_(buffer_),
-        pushback_buffer_end_cache_(NULL),
-        pushback_buffer_backing_(NULL),
-        pushback_buffer_backing_size_(0) {
-    buffer_cursor_ = buffer_end_ = buffer_ + kPushBackSize;
-  }
+  explicit InputStreamUTF16Buffer(UnicodeInputStream* stream)
+      : UTF16Buffer(),
+        stream_(stream) { }
 
-  virtual ~InputStreamUTF16Buffer() {
-    if (pushback_buffer_backing_ != NULL) {
-      DeleteArray(pushback_buffer_backing_);
-    }
-  }
+  virtual ~InputStreamUTF16Buffer() { }
 
-  virtual void PushBack(uc16 ch) {
-    ASSERT(pos_ > 0);
-    if (buffer_cursor_ <= pushback_buffer_) {
-      // No more room in the current buffer to do pushbacks.
-      if (pushback_buffer_end_cache_ == NULL) {
-        // We have overflowed the pushback space at the beginning of buffer_.
-        // Switch to using a separate allocated pushback buffer.
-        if (pushback_buffer_backing_ == NULL) {
-          // Allocate a buffer the first time we need it.
-          pushback_buffer_backing_ = NewArray<uc16>(kPushBackSize);
-          pushback_buffer_backing_size_ = kPushBackSize;
-        }
-        pushback_buffer_ = pushback_buffer_backing_;
-        pushback_buffer_end_cache_ = buffer_end_;
-        buffer_end_ = pushback_buffer_backing_ + pushback_buffer_backing_size_;
-        buffer_cursor_ = buffer_end_ - 1;
-      } else {
-        // Hit the bottom of the allocated pushback buffer.
-        // Double the buffer and continue.
-        uc16* new_buffer = NewArray<uc16>(pushback_buffer_backing_size_ * 2);
-        memcpy(new_buffer + pushback_buffer_backing_size_,
-               pushback_buffer_backing_,
-               pushback_buffer_backing_size_);
-        DeleteArray(pushback_buffer_backing_);
-        buffer_cursor_ = new_buffer + pushback_buffer_backing_size_;
-        pushback_buffer_backing_ = pushback_buffer_ = new_buffer;
-        buffer_end_ = pushback_buffer_backing_ + pushback_buffer_backing_size_;
-      }
-    }
-    pushback_buffer_[buffer_cursor_ - pushback_buffer_- 1] = ch;
+  virtual void PushBack(uc32 ch) {
+    stream_->PushBack(ch);
     pos_--;
   }
 
- protected:
-  virtual bool ReadBlock() {
-    if (pushback_buffer_end_cache_ != NULL) {
-      buffer_cursor_ = buffer_;
-      buffer_end_ = pushback_buffer_end_cache_;
-      pushback_buffer_end_cache_ = NULL;
-      return buffer_end_ > buffer_cursor_;
-    }
-    // Copy the top of the buffer into the pushback area.
-    int32_t value;
-    uc16* buffer_start = buffer_ + kPushBackSize;
-    buffer_cursor_ = buffer_end_ = buffer_start;
-    while ((value = stream_->Next()) >= 0) {
-      if (value > static_cast<int32_t>(unibrow::Utf8::kMaxThreeByteChar)) {
-        value = unibrow::Utf8::kBadChar;
-      }
-      // buffer_end_ is a const pointer, but buffer_ is writable.
-      buffer_start[buffer_end_++ - buffer_start] = static_cast<uc16>(value);
-      if (buffer_end_ == buffer_ + kPushBackSize + kBufferSize) break;
-    }
-    return buffer_end_ > buffer_start;
+  virtual uc32 Advance() {
+    uc32 result = stream_->Next();
+    if (result >= 0) pos_++;
+    return result;
   }
 
-  virtual unsigned SlowSeekForward(unsigned pos) {
+  virtual void SeekForward(int pos) {
     // Seeking in the input is not used by preparsing.
     // It's only used by the real parser based on preparser data.
     UNIMPLEMENTED();
-    return 0;
   }
 
  private:
-  static const unsigned kBufferSize = 512;
-  static const unsigned kPushBackSize = 16;
   v8::UnicodeInputStream* const stream_;
-  // Buffer holding first kPushBackSize characters of pushback buffer,
-  // then kBufferSize chars of read-ahead.
-  // The pushback buffer is only used if pushing back characters past
-  // the start of a block.
-  uc16 buffer_[kPushBackSize + kBufferSize];
-  // Limit of pushbacks before new allocation is necessary.
-  uc16* pushback_buffer_;
-  // Only if that pushback buffer at the start of buffer_ isn't sufficient
-  // is the following used.
-  const uc16* pushback_buffer_end_cache_;
-  uc16* pushback_buffer_backing_;
-  unsigned pushback_buffer_backing_size_;
 };
 
 
 class StandAloneJavaScriptScanner : public JavaScriptScanner {
  public:
-  void Initialize(UC16CharacterStream* source) {
+  void Initialize(UTF16Buffer* source) {
     source_ = source;
     literal_flags_ = kLiteralString | kLiteralIdentifier;
     Init();
     // Skip initial whitespace allowing HTML comment ends just like
     // after a newline and scan first token.
     has_line_terminator_before_next_ = true;
     SkipWhiteSpace();
     Scan();
   }
 };
 
 
 // Functions declared by allocation.h
 
 void FatalProcessOutOfMemory(const char* reason) {
   V8_Fatal(__FILE__, __LINE__, reason);
 }
 
 bool EnableSlowAsserts() { return true; }
 
+
 }  // namespace internal.
 
 
 UnicodeInputStream::~UnicodeInputStream() { }
 
 
 PreParserData Preparse(UnicodeInputStream* input, size_t max_stack) {
   internal::InputStreamUTF16Buffer buffer(input);
   uintptr_t stack_limit = reinterpret_cast<uintptr_t>(&buffer) - max_stack;
   internal::StandAloneJavaScriptScanner scanner;
@@ skipping 13 matching lines @@
   return PreParserData(size, data);
 }
 
 }  // namespace v8.
 
 
 // Used by ASSERT macros and other immediate exits.
 extern "C" void V8_Fatal(const char* file, int line, const char* format, ...) {
   exit(EXIT_FAILURE);
 }