FileTokenizer.cpp

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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]

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

#include "FileTokenizer.hpp"
#include "MsqError.hpp"
#include <cstring>
#include <cctype>
#include <cstdlib>

namespace MBMesquite
{

FileTokenizer::FileTokenizer( std::FILE* file_ptr )
    : filePtr( file_ptr ), nextToken( buffer ), bufferEnd( buffer ), lineNumber( 1 ), lastChar( '\0' )
{
}

FileTokenizer::~FileTokenizer()
{
    fclose( filePtr );
}

bool FileTokenizer::eof() const
{
    return nextToken == bufferEnd && feof( filePtr );
}

const char* FileTokenizer::get_string( MsqError& err )
{
    // If the whitepsace character marking the end of the
    // last token was a newline, increment the line count.
    if( lastChar == '\n' ) ++lineNumber;

    // Loop until either found the start of a token to return or have
    // reached the end of the file.
    for( ;; )
    {
        // If the buffer is empty, read more.
        if( nextToken == bufferEnd )
        {
            size_t count = fread( buffer, 1, sizeof( buffer ) - 1, filePtr );
            if( !count )
            {
                if( feof( filePtr ) )
                    MSQ_SETERR( err )( "File truncated.\n", MsqError::PARSE_ERROR );
                else
                    MSQ_SETERR( err )( MsqError::IO_ERROR );
                return NULL;
            }

            nextToken = buffer;
            bufferEnd = buffer + count;
        }

        // If the current character is not a space, we've found a token.
        if( !isspace( *nextToken ) ) break;

        // If the current space character is a newline,
        // increment the line number count.
        if( *nextToken == '\n' ) ++lineNumber;
        ++nextToken;
    }

    // Store the start of the token in "result" and
    // advance "nextToken" to one past the end of the
    // token.
    char* result = nextToken;
    while( nextToken != bufferEnd && !isspace( *nextToken ) )
        ++nextToken;

    // If we have reached the end of the buffer without finding
    // a whitespace character terminating the token, we need to
    // read more from the file.  Only try once.  If the token is
    // too large to fit in the buffer, give up.
    if( nextToken == bufferEnd )
    {
        // Shift the (possibly) partial token to the start of the buffer.
        size_t remaining = bufferEnd - result;
        memmove( buffer, result, remaining );
        result    = buffer;
        nextToken = result + remaining;

        // Fill the remainder of the buffer after the token.
        size_t count = fread( nextToken, 1, sizeof( buffer ) - remaining - 1, filePtr );
        if( !count && !feof( filePtr ) )
        {
            MSQ_SETERR( err )( "I/O error.\n", MsqError::IO_ERROR );
            return NULL;
        }
        bufferEnd = nextToken + count;

        // Continue to advance nextToken until we find the space
        // terminating the token.
        while( nextToken != bufferEnd && !isspace( *nextToken ) )
            ++nextToken;

        if( nextToken == bufferEnd )  // EOF
        {
            *bufferEnd = '\0';
            ++bufferEnd;
        }
    }

    // Save terminating whitespace character (or NULL char if EOF).
    lastChar = *nextToken;
    // Put null in buffer to mark end of current token.
    *nextToken = '\0';
    // Advance nextToken to the next character to search next time.
    ++nextToken;
    return result;
}

bool FileTokenizer::get_double_internal( double& result, MsqError& err )
{
    // Get a token
    const char *token_end, *token = get_string( err );
    if( MSQ_CHKERR( err ) ) return false;

    // Check for hex value -- on some platforms (e.g. Linux), strtod
    // will accept hex values, on others (e.g. Sun) it wil not.  Force
    // failure on hex numbers for consistancy.
    if( token[0] && token[1] && token[0] == '0' && toupper( token[1] ) == 'X' )
    {
        MSQ_SETERR( err )
        ( MsqError::PARSE_ERROR, "Syntax error at line %d: expected number, got \"%s\"", line_number(), token );
        return false;
    }

    // Parse token as double
    result = strtod( token, (char**)&token_end );

    // If the one past the last char read by strtod is
    // not the NULL character terminating the string,
    // then parse failed.
    if( *token_end )
    {
        MSQ_SETERR( err )
        ( MsqError::PARSE_ERROR, "Syntax error at line %d: expected number, got \"%s\"", line_number(), token );
        return false;
    }

    return true;
}

bool FileTokenizer::get_float_internal( float& result, MsqError& err )
{
    double d = 0.0;
    get_double_internal( d, err );
    if( MSQ_CHKERR( err ) ) return false;

    result = (float)d;
    if( d != (double)result )
    {
        MSQ_SETERR( err )( MsqError::PARSE_ERROR, "Numberic overflow at line %d.", line_number() );
        return false;
    }

    return true;
}

bool FileTokenizer::get_long_int_internal( long& result, MsqError& err )
{
    // Get a token
    const char *token_end, *token = get_string( err );
    if( MSQ_CHKERR( err ) ) return false;

    // Parse token as long
    result = strtol( token, (char**)&token_end, 0 );

    // If the one past the last char read by strtol is
    // not the NULL character terminating the string,
    // then parse failed.
    if( *token_end )
    {
        MSQ_SETERR( err )
        ( MsqError::PARSE_ERROR, "Syntax error at line %d: expected integer, got \"%s\"", line_number(), token );
        return false;
    }

    return true;
}

bool FileTokenizer::get_byte_internal( unsigned char& result, MsqError& err )
{
    long i = 0;
    get_long_int_internal( i, err );
    if( MSQ_CHKERR( err ) ) return false;

    result = (unsigned char)i;
    if( i != (long)result )
    {
        MSQ_SETERR( err )( MsqError::PARSE_ERROR, "Numberic overflow at line %d.", line_number() );
        return false;
    }

    return true;
}

bool FileTokenizer::get_short_int_internal( short& result, MsqError& err )
{
    long i = 0;
    get_long_int_internal( i, err );
    if( MSQ_CHKERR( err ) ) return false;

    result = (short)i;
    if( i != (long)result )
    {
        MSQ_SETERR( err )( MsqError::PARSE_ERROR, "Numberic overflow at line %d.", line_number() );
        return false;
    }

    return true;
}

bool FileTokenizer::get_integer_internal( int& result, MsqError& err )
{
    long i = 0;
    get_long_int_internal( i, err );
    if( MSQ_CHKERR( err ) ) return false;

    result = (int)i;
    if( i != (long)result )
    {
        MSQ_SETERR( err )( MsqError::PARSE_ERROR, "Numberic overflow at line %d.", line_number() );
        return false;
    }

    return true;
}

bool FileTokenizer::get_boolean_internal( bool& result, MsqError& err )
{
    // Get a token
    const char* token = get_string( err );
    if( MSQ_CHKERR( err ) ) return false;

    if( token[1] || ( token[0] != '0' && token[0] != '1' ) )
    {
        MSQ_SETERR( err )
        ( MsqError::PARSE_ERROR, "Syntax error at line %d: expected 0 or 1, got \"%s\"", line_number(), token );
        return false;
    }

    result = token[0] == '1';
    return true;
}

bool FileTokenizer::get_floats( size_t count, float* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        if( !get_float_internal( *array, err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_doubles( size_t count, double* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_double_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_bytes( size_t count, unsigned char* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_byte_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_short_ints( size_t count, short* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_short_int_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_integers( size_t count, int* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_integer_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_long_ints( size_t count, long* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_long_int_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

bool FileTokenizer::get_booleans( size_t count, bool* array, MsqError& err )
{
    for( size_t i = 0; i < count; ++i )
    {
        get_boolean_internal( *array, err );
        if( MSQ_CHKERR( err ) ) return false;
        ++array;
    }
    return true;
}

void FileTokenizer::unget_token()
{
    if( nextToken - buffer < 2 ) return;

    --nextToken;
    *nextToken = lastChar;
    --nextToken;
    while( nextToken > buffer && *nextToken )
        --nextToken;

    if( !*nextToken ) ++nextToken;

    lastChar = '\0';
}

bool FileTokenizer::match_token( const char* str, MsqError& err )
{
    // Get a token
    const char* token = get_string( err );
    if( MSQ_CHKERR( err ) ) return false;

    // Check if it matches
    if( 0 == strcmp( token, str ) ) return true;

    // Construct error message
    MSQ_SETERR( err )
    ( MsqError::PARSE_ERROR, "Syntax error at line %d: expected \"%s\", got \"%s\"", line_number(), str, token );
    return false;
}  // namespace MBMesquite

int FileTokenizer::match_token( const char* const* list, MsqError& err )
{
    // Get a token
    const char* token = get_string( err );
    if( MSQ_CHKERR( err ) ) return false;

    // Check if it matches any input string
    const char* const* ptr;
    for( ptr = list; *ptr; ++ptr )
        if( 0 == strcmp( token, *ptr ) ) return ptr - list + 1;

    // No match, constuct error message
    std::string message( "Parsing error at line " );
    char lineno[16];
    sprintf( lineno, "%d", line_number() );
    message += lineno;
    message += ": expected one of {";
    for( ptr = list; *ptr; ++ptr )
    {
        message += " ";
        message += *ptr;
    }
    message += " } got \"";
    message += token;
    message += "\"";
    MSQ_SETERR( err )( message, MsqError::PARSE_ERROR );
    return false;
}

bool FileTokenizer::get_newline( MsqError& err )
{
    if( lastChar == '\n' )
    {
        lastChar = ' ';
        ++lineNumber;
        return true;
    }

    // Loop until either we a) find a newline, b) find a non-whitespace
    // character or c) reach the end of the file.
    for( ;; )
    {
        // If the buffer is empty, read more.
        if( nextToken == bufferEnd )
        {
            size_t count = fread( buffer, 1, sizeof( buffer ), filePtr );
            if( !count )
            {
                if( eof() )
                    MSQ_SETERR( err )( "File truncated.", MsqError::PARSE_ERROR );
                else
                    MSQ_SETERR( err )( MsqError::IO_ERROR );
                return false;
            }

            nextToken = buffer;
            bufferEnd = buffer + count;
        }

        // If the current character is not a space, the we've failed.
        if( !isspace( *nextToken ) )
        {
            MSQ_SETERR( err )
            ( MsqError::PARSE_ERROR, "Expected newline at line %d.", line_number() );
            return false;
        }

        // If the current space character is a newline,
        // increment the line number count.
        if( *nextToken == '\n' )
        {
            ++lineNumber;
            ++nextToken;
            lastChar = ' ';
            return true;
        }
        ++nextToken;
    }

    // should never reach this
    return false;
}

}  // namespace MBMesquite