1 // Copyright 2011 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_SCANNER_CHARACTER_STREAMS_H_ 6 #define V8_SCANNER_CHARACTER_STREAMS_H_ 7 8 #include "src/scanner.h" 9 10 namespace v8 { 11 namespace internal { 12 13 // A buffered character stream based on a random access character 14 // source (ReadBlock can be called with pos_ pointing to any position, 15 // even positions before the current). 16 class BufferedUtf16CharacterStream: public Utf16CharacterStream { 17 public: 18 BufferedUtf16CharacterStream(); 19 virtual ~BufferedUtf16CharacterStream(); 20 21 virtual void PushBack(uc32 character); 22 23 protected: 24 static const unsigned kBufferSize = 512; 25 static const unsigned kPushBackStepSize = 16; 26 27 virtual unsigned SlowSeekForward(unsigned delta); 28 virtual bool ReadBlock(); 29 virtual void SlowPushBack(uc16 character); 30 31 virtual unsigned BufferSeekForward(unsigned delta) = 0; 32 virtual unsigned FillBuffer(unsigned position, unsigned length) = 0; 33 34 const uc16* pushback_limit_; 35 uc16 buffer_[kBufferSize]; 36 }; 37 38 39 // Generic string stream. 40 class GenericStringUtf16CharacterStream: public BufferedUtf16CharacterStream { 41 public: 42 GenericStringUtf16CharacterStream(Handle<String> data, 43 unsigned start_position, 44 unsigned end_position); 45 virtual ~GenericStringUtf16CharacterStream(); 46 47 protected: 48 virtual unsigned BufferSeekForward(unsigned delta); 49 virtual unsigned FillBuffer(unsigned position, unsigned length); 50 51 Handle<String> string_; 52 unsigned length_; 53 }; 54 55 56 // Utf16 stream based on a literal UTF-8 string. 57 class Utf8ToUtf16CharacterStream: public BufferedUtf16CharacterStream { 58 public: 59 Utf8ToUtf16CharacterStream(const byte* data, unsigned length); 60 virtual ~Utf8ToUtf16CharacterStream(); 61 62 protected: 63 virtual unsigned BufferSeekForward(unsigned delta); 64 virtual unsigned FillBuffer(unsigned char_position, unsigned length); 65 void SetRawPosition(unsigned char_position); 66 67 const byte* raw_data_; 68 unsigned raw_data_length_; // Measured in bytes, not characters. 69 unsigned raw_data_pos_; 70 // The character position of the character at raw_data[raw_data_pos_]. 71 // Not necessarily the same as pos_. 72 unsigned raw_character_position_; 73 }; 74 75 76 // UTF16 buffer to read characters from an external string. 77 class ExternalTwoByteStringUtf16CharacterStream: public Utf16CharacterStream { 78 public: 79 ExternalTwoByteStringUtf16CharacterStream(Handle<ExternalTwoByteString> data, 80 int start_position, 81 int end_position); 82 virtual ~ExternalTwoByteStringUtf16CharacterStream(); 83 PushBack(uc32 character)84 virtual void PushBack(uc32 character) { 85 ASSERT(buffer_cursor_ > raw_data_); 86 buffer_cursor_--; 87 pos_--; 88 } 89 90 protected: SlowSeekForward(unsigned delta)91 virtual unsigned SlowSeekForward(unsigned delta) { 92 // Fast case always handles seeking. 93 return 0; 94 } ReadBlock()95 virtual bool ReadBlock() { 96 // Entire string is read at start. 97 return false; 98 } 99 Handle<ExternalTwoByteString> source_; 100 const uc16* raw_data_; // Pointer to the actual array of characters. 101 }; 102 103 } } // namespace v8::internal 104 105 #endif // V8_SCANNER_CHARACTER_STREAMS_H_ 106