// Copyright (C) 2005, Ondra Kamenik

// $Id: memory_file.h 762 2006-05-22 13:00:07Z kamenik $

#ifndef OGU_MEMORY_FILE
#define OGU_MEMORY_FILE

namespace ogu
{
  /** This function calculates an offset of a given position in a
   * given string. The position is given by the line number and by
   * the offset in the line (both starting from 1). */
  int calc_pos_offset(int length, const char *str, int line, int col);
  /** This function calculates a line number and column number of a
   * character given by the offset in the string. It is inverse to
   * calc_pos_offset. */
  void calc_pos_line_and_col(int length, const char *str, int offset,
                             int &line, int &col);

  /** This class opens a given file and makes its copy in memory and
   * appends it with the '\0' character. Since the type of length is
   * int, it can store files with size at most 4GB. If the file
   * could be opened for reading, data is NULL and length is -1. If
   * the file is empty but exists, len is zero and data points to a
   * newly allocated memory containing '\0' character at the end. */
  class MemoryFile
  {
  protected:
    int len;
    char *data;
  public:
    MemoryFile(const char *fname);
    virtual ~MemoryFile()
    {
      if (data)
        delete [] data;
    }
    int
    length() const
    {
      return len;
    }
    const char *
    base() const
    {
      return data;
    }
    bool
    exists() const
    {
      return len != -1;
    }
    /** Return the offset of a character in the given line
     * (starting from 1) with the given offset in the line. */
    int
    offset(int line, int lineoff) const
    {
      return calc_pos_offset(len, data, line, lineoff);
    }
    /** Return the line number and column number of the character
     * defined by the offset. */
    void
    line_and_col(int offset, int &line, int &col) const
    {
      calc_pos_line_and_col(len, data, offset, line, col);
    }
  };

};

#endif

// Local Variables:
// mode:C++
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