FileTokenizer.hpp

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/* *****************************************************************
    MESQUITE -- The Mesh Quality Improvement Toolkit

    Copyright 2004 Lawrence Livermore National Laboratory.  Under
    the terms of Contract B545069 with the University of Wisconsin --
    Madison, Lawrence Livermore National Laboratory 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.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    (lgpl.txt) along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    [email protected]

  ***************************************************************** */

#ifndef FILE_TOKENIZER_HPP
#define FILE_TOKENIZER_HPP

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

namespace MBMesquite
{

class MsqError;

/**
 * \class  FileTokenizer
 * \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.
     */
    FileTokenizer( std::FILE* file_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 whitesapce-deliminated 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 occured.
     */
    const char* get_string( MsqError& err );

    /** \brief check for newline
     *
     * Consume whitespace upto 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( MsqError& err );

    /** \brief Parse a sequence of double values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of float values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of integer values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /** \brief Parse a sequence of bit or boolean values.
     *
     * Read the specified number of space-deliminated 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, MsqError& err );

    /**
     * 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, MsqError& err );

    /**
     * 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, MsqError& err );

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

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

    /** 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 MBMesquite

#endif