/* vim: set ts=4 sw=4 tw=99 et:
 *
 * Copyright (C) 2012 David Anderson
 *
 * This file is part of SourcePawn.
 *
 * SourcePawn is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 * 
 * SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * SourcePawn. If not, see http://www.gnu.org/licenses/.
 */
#ifndef _include_jitcraft_scanner_h_
#define _include_jitcraft_scanner_h_

#include "Token.h"
#include "CompileContext.h"
#include "../Opcodes.h"
#include "../Vector.h"

namespace ke {

class Scanner
{
    template <bool Enabled>
    friend class AutoAllowTags;

    CompileContext &cc_;
    const char *stream_;
    size_t length_;
    bool pushed_;
    bool allowTags_;
    char saved_;
    const char *pos_;
    Vector<char> literal_;
    TokenKind lastToken_;
    SourcePosition last_;
    SourcePosition cur_;
    SourcePosition begin_;

  private:
    char getChar();
    void putChar(char c);
    void eatSingleLine();
    bool eatComment();
    void calcNewLine(char c);
    int readEscapeCode();
    TokenKind stringLiteral();
    TokenKind hexLiteral();
    TokenKind numberLiteral(char first);
    TokenKind identifier(char first);

    TokenKind next();

  public:
    Scanner(CompileContext &cc, const char *stream, size_t length);

    static double ParseDouble(const char *string);

    TokenKind scan();
    TokenKind peek();
    TokenKind last() const {
        return lastToken_;
    }

    bool tagsEnabled() const {
        return allowTags_;
    }
    void setTagsEnabled(bool enabled) {
        allowTags_ = enabled;
    }

    // Beginning source position of the last instruction.
    SourcePosition begin() const {
        return begin_;
    }

    // Note: the literal may have embedded NUL characters.
    const char *literal() const {
        return literal_.buffer();
    }
    size_t literal_length() const {
        return literal_.length() - 1;
    }
};

template <bool Enabled>
class AutoAllowTags
{
    Scanner &scanner_;
    bool prev_;

  public:
    AutoAllowTags(Scanner &scanner)
      : scanner_(scanner),
        prev_(scanner_.tagsEnabled())
    {
        scanner_.setTagsEnabled(Enabled);
    }
    ~AutoAllowTags()
    {
        scanner_.setTagsEnabled(prev_);
    }
};

} // namespace ke

#endif // _include_jitcraft_scanner_h_