| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_SCANNER_CHARACTER_STREAMS_H_ |
| #define V8_SCANNER_CHARACTER_STREAMS_H_ |
| |
| #include "src/scanner.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // A buffered character stream based on a random access character |
| // source (ReadBlock can be called with pos_ pointing to any position, |
| // even positions before the current). |
| class BufferedUtf16CharacterStream: public Utf16CharacterStream { |
| public: |
| BufferedUtf16CharacterStream(); |
| virtual ~BufferedUtf16CharacterStream(); |
| |
| virtual void PushBack(uc32 character); |
| |
| protected: |
| static const unsigned kBufferSize = 512; |
| static const unsigned kPushBackStepSize = 16; |
| |
| virtual unsigned SlowSeekForward(unsigned delta); |
| virtual bool ReadBlock(); |
| virtual void SlowPushBack(uc16 character); |
| |
| virtual unsigned BufferSeekForward(unsigned delta) = 0; |
| virtual unsigned FillBuffer(unsigned position) = 0; |
| |
| const uc16* pushback_limit_; |
| uc16 buffer_[kBufferSize]; |
| }; |
| |
| |
| // Generic string stream. |
| class GenericStringUtf16CharacterStream: public BufferedUtf16CharacterStream { |
| public: |
| GenericStringUtf16CharacterStream(Handle<String> data, |
| unsigned start_position, |
| unsigned end_position); |
| virtual ~GenericStringUtf16CharacterStream(); |
| |
| protected: |
| virtual unsigned BufferSeekForward(unsigned delta); |
| virtual unsigned FillBuffer(unsigned position); |
| |
| Handle<String> string_; |
| unsigned length_; |
| }; |
| |
| |
| // Utf16 stream based on a literal UTF-8 string. |
| class Utf8ToUtf16CharacterStream: public BufferedUtf16CharacterStream { |
| public: |
| Utf8ToUtf16CharacterStream(const byte* data, unsigned length); |
| virtual ~Utf8ToUtf16CharacterStream(); |
| |
| protected: |
| virtual unsigned BufferSeekForward(unsigned delta); |
| virtual unsigned FillBuffer(unsigned char_position); |
| void SetRawPosition(unsigned char_position); |
| |
| const byte* raw_data_; |
| unsigned raw_data_length_; // Measured in bytes, not characters. |
| unsigned raw_data_pos_; |
| // The character position of the character at raw_data[raw_data_pos_]. |
| // Not necessarily the same as pos_. |
| unsigned raw_character_position_; |
| }; |
| |
| |
| // UTF16 buffer to read characters from an external string. |
| class ExternalTwoByteStringUtf16CharacterStream: public Utf16CharacterStream { |
| public: |
| ExternalTwoByteStringUtf16CharacterStream(Handle<ExternalTwoByteString> data, |
| int start_position, |
| int end_position); |
| virtual ~ExternalTwoByteStringUtf16CharacterStream(); |
| |
| virtual void PushBack(uc32 character) { |
| DCHECK(buffer_cursor_ > raw_data_); |
| buffer_cursor_--; |
| pos_--; |
| } |
| |
| protected: |
| virtual unsigned SlowSeekForward(unsigned delta) { |
| // Fast case always handles seeking. |
| return 0; |
| } |
| virtual bool ReadBlock() { |
| // Entire string is read at start. |
| return false; |
| } |
| Handle<ExternalTwoByteString> source_; |
| const uc16* raw_data_; // Pointer to the actual array of characters. |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_SCANNER_CHARACTER_STREAMS_H_ |