FileTokenizer.hpp

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/**
 * MOAB, a Mesh-Oriented datABase, is a software component for creating,
 * storing and accessing finite element mesh data.
 *
 * Copyright 2004 Sandia Corporation.  Under the terms of Contract
 * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
 * retains certain rights in this software.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 */

#ifndef FILE_TOKENIZER_HPP
#define FILE_TOKENIZER_HPP

#include "moab/Types.hpp"
#include <cstdio>
#include <sys/types.h>

namespace moab
{

class ReadUtilIface;

/**
 * \brief  Parse a file as space-separated tokens
 * \author Jason Kraftcheck
 * \date   30 Sept 2004
 *
 * Read a file, separating it into space-separated tokens.
 * This is provided in place of using the standard C or C++
 * file parsing routines because it counts lines, which is
 * useful for error reporting.  Also provides some useful
 * utility methods for parsing VTK files (which is the
 * intended use of this implementation.)
 *
 * Uses raw reads/writes, implementing internal buffering.
 * Token size may not exceed buffer size.
 */

class FileTokenizer
{
  public:
    /** \brief constructor
     *
     * \param file_ptr The file to read from.
     * \param read_util_ptr Pointer to ReadUtilIface to use for
     *                      reporting errors.
     */
    FileTokenizer( std::FILE* file_ptr, ReadUtilIface* read_util_ptr );

    /** \brief destructor : closes file.
     *
     * The destructor closes the passed file handle.   This
     * is done as a convenience feature.  If the caller
     * creates an instance of this object on the stack, the
     * file will automatically be closed when the caller
     * returns.
     */
    ~FileTokenizer();

    /** \brief get next token
     *
     * Get the next whitespace-delimited token from the file.
     * NOTE: The returned string is only valid until the next
     *       call to any of the functions in this class that
     *       read from the file.
     *
     * \return A pointer to the buffer space containing the string,
     *         or NULL if an error occurred.
     */
    const char* get_string();

    /** \brief check for newline
     *
     * Consume whitespace up to and including the next newline.
     * If a non-space character is found before a newline,
     * the function will stop, set the error message, and
     * return false.
     *
     * \return True if a newline was found before any non-space
     *         character.  False otherwise.
     */
    bool get_newline( bool report_error = true );

    /** \brief Parse a sequence of double values.
     *
     * Read the specified number of space-delimited doubles.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_doubles( size_t count, double* array );

    /** \brief Parse a sequence of float values.
     *
     * Read the specified number of space-delimited doubles.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_floats( size_t count, float* array );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-delimited ints.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_integers( size_t count, int* array );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-delimited ints.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_long_ints( size_t count, long* array );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-delimited ints.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_short_ints( size_t count, short* array );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-delimited ints.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_bytes( size_t count, unsigned char* array );

    /** \brief Read binary data (interleaved with ASCII)
     *
     * Read a block of binary data.
     *\param bytes  Number of bytes to read
     *\param mem    Memory address at which to store data.
     */
    bool get_binary( size_t bytes, void* mem );

    /** \brief Parse a sequence of bit or boolean values.
     *
     * Read the specified number of space-delimited values.
     *
     * \param count   The number of values to read.
     * \param array   The memory at which to store the values.
     * \return true if successful, false otherwise.
     */
    bool get_booleans( size_t count, bool* array );

    /**
     * Check for end-of-file condition.
     */
    bool eof() const;

    /**
     * Get the line number the last token was read from.
     */
    int line_number() const
    {
        return lineNumber;
    }

    /**
     * Put current token back in buffer.  Can only unget one token.
     */
    void unget_token();

    /**
     * Match current token to passed string.  If token
     * doesn't match, set error message.
     */
    bool match_token( const char* string, bool print_error = true );

    /**
     * Match the current token to one of an array of strings.
     * Sets the error message if the current token doesn't
     * match any of the input strings.
     *
     * \param  string_list A NULL-terminated array of strings.
     * \return One greater than the index of the matched
     *         string, or zero if no match.
     */
    int match_token( const char* const* string_list, bool print_error = true );

  private:
    /** Internal implementation of \ref get_doubles */
    bool get_double_internal( double& result );
    /** Internal implementation of \ref get_long_ints */
    bool get_long_int_internal( long& result );
    /** Internal implementation of \ref get_Booleans */
    bool get_boolean_internal( bool& result );

    /** Internal implementation of \ref get_floats */
    bool get_float_internal( float& result );
    /** Internal implementation of \ref get_integers */
    bool get_integer_internal( int& result );
    /** Internal implementation of \ref get_short_ints */
    bool get_short_int_internal( short& result );
    /** Internal implementation of \ref get_bytes */
    bool get_byte_internal( unsigned char& result );

    /** Pointer to standard C FILE struct */
    std::FILE* filePtr;

    /** Input buffer */
    char buffer[512];

    /** One past the end of the last token returned */
    char* nextToken;
    /** One past the last used byte of the buffer */
    char* bufferEnd;

    /** Line number of last returned token */
    int lineNumber;

    /** The whitespace character marking the end of the
     *  last returned token.  Saved here because if it
     *  is a newline, the line count will need to be
     *  incremented when the next token is returned.
     */
    char lastChar;
};

}  // namespace moab

#endif