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// 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.
#ifndef V8_SCANNER_H_
#define V8_SCANNER_H_
#include "token.h"
#include "char-predicates-inl.h"
#include "scanner-base.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 BufferedUC16CharacterStream: public UC16CharacterStream {
public:
BufferedUC16CharacterStream();
virtual ~BufferedUC16CharacterStream();
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, unsigned length) = 0;
const uc16* pushback_limit_;
uc16 buffer_[kBufferSize];
};
// Generic string stream.
class GenericStringUC16CharacterStream: public BufferedUC16CharacterStream {
public:
GenericStringUC16CharacterStream(Handle<String> data,
unsigned start_position,
unsigned end_position);
virtual ~GenericStringUC16CharacterStream();
protected:
virtual unsigned BufferSeekForward(unsigned delta);
virtual unsigned FillBuffer(unsigned position, unsigned length);
Handle<String> string_;
unsigned start_position_;
unsigned length_;
};
// UC16 stream based on a literal UTF-8 string.
class Utf8ToUC16CharacterStream: public BufferedUC16CharacterStream {
public:
Utf8ToUC16CharacterStream(const byte* data, unsigned length);
virtual ~Utf8ToUC16CharacterStream();
protected:
virtual unsigned BufferSeekForward(unsigned delta);
virtual unsigned FillBuffer(unsigned char_position, unsigned length);
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 ExternalTwoByteStringUC16CharacterStream: public UC16CharacterStream {
public:
ExternalTwoByteStringUC16CharacterStream(Handle<ExternalTwoByteString> data,
int start_position,
int end_position);
virtual ~ExternalTwoByteStringUC16CharacterStream();
virtual void PushBack(uc32 character) {
ASSERT(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.
};
// ----------------------------------------------------------------------------
// V8JavaScriptScanner
// JavaScript scanner getting its input from either a V8 String or a unicode
// CharacterStream.
class V8JavaScriptScanner : public JavaScriptScanner {
public:
V8JavaScriptScanner();
void Initialize(UC16CharacterStream* source);
};
class JsonScanner : public Scanner {
public:
JsonScanner();
void Initialize(UC16CharacterStream* source);
// Returns the next token.
Token::Value Next();
protected:
// Skip past JSON whitespace (only space, tab, newline and carrige-return).
bool SkipJsonWhiteSpace();
// Scan a single JSON token. The JSON lexical grammar is specified in the
// ECMAScript 5 standard, section 15.12.1.1.
// Recognizes all of the single-character tokens directly, or calls a function
// to scan a number, string or identifier literal.
// The only allowed whitespace characters between tokens are tab,
// carriage-return, newline and space.
void ScanJson();
// A JSON number (production JSONNumber) is a subset of the valid JavaScript
// decimal number literals.
// It includes an optional minus sign, must have at least one
// digit before and after a decimal point, may not have prefixed zeros (unless
// the integer part is zero), and may include an exponent part (e.g., "e-10").
// Hexadecimal and octal numbers are not allowed.
Token::Value ScanJsonNumber();
// A JSON string (production JSONString) is subset of valid JavaScript string
// literals. The string must only be double-quoted (not single-quoted), and
// the only allowed backslash-escapes are ", /, \, b, f, n, r, t and
// four-digit hex escapes (uXXXX). Any other use of backslashes is invalid.
Token::Value ScanJsonString();
// Used to recognizes one of the literals "true", "false", or "null". These
// are the only valid JSON identifiers (productions JSONBooleanLiteral,
// JSONNullLiteral).
Token::Value ScanJsonIdentifier(const char* text, Token::Value token);
};
} } // namespace v8::internal
#endif // V8_SCANNER_H_
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