/*

 * Floating point (IEEE 754) functions

 *

 * Copyright (C) 2011-2024, Joachim Metz <joachim.metz@gmail.com>

 *

 * Refer to AUTHORS for acknowledgements.

 *

 * This program 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 3 of the License, or

 * (at your option) any later version.

 *

 * This program 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 Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

#include <common.h>

#include <byte_stream.h>

#include <types.h>

#include "libfwevt_floating_point.h"

#include "libfwevt_libcerror.h"

/* Deterimes the size of the string of a 32-bit floating point

 * The string size includes the end of string character

 * Returns 1 if successful or -1 on error

 */

int libfwevt_float32_get_string_size(

     uint32_t value_32bit,

     size_t *string_size,

     libcerror_error_t **error )

{

  static char *function        = "libfwevt_float32_get_string_size";

  uint8_t is_indeterminate     = 0;

  uint8_t is_infinite          = 0;

  uint8_t is_not_a_number      = 0;

  uint8_t is_negative          = 0;

  uint8_t number_of_characters = 0;

  if( string_size == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid string size.",

     function );

    return( -1 );

  }

  is_negative = (uint8_t) ( value_32bit >> 31 );

  if( is_negative != 0 )

  {

    value_32bit &= ~( (uint32_t) 1 << 31 );

  }

  if( value_32bit == 0x7f800000UL )

  {

    is_infinite = 1;

  }

  else if( ( is_negative != 0 )

        && ( value_32bit == 0x7fc00000UL ) )

  {

    is_indeterminate = 1;

  }

  else if( ( value_32bit >= 0x7f800001UL )

        && ( value_32bit <= 0x7fffffffUL ) )

  {

    is_not_a_number = 1;

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    number_of_characters = 4;

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      number_of_characters = 15;

    }

    else

    {

      number_of_characters = 14;

    }

  }

  *string_size = number_of_characters;

  return( 1 );

}

/* Copies a 32-bit floating point to an UTF-8 string

 * The string size should include the end of string character

 * Returns 1 if successful or -1 on error

 */

int libfwevt_float32_copy_to_utf8_string_with_index(

     uint32_t value_32bit,

     uint8_t *utf8_string,

     size_t utf8_string_size,

     size_t *utf8_string_index,

     libcerror_error_t **error )

{

  byte_stream_float32_t value_float32;

  static char *function         = "libfwevt_float32_copy_to_utf8_string_with_index";

  size_t safe_utf8_string_index = 0;

  uint32_t divider              = 0;

  uint32_t value_fraction       = 0;

  int16_t exponent10            = 0;

  int16_t exponent2             = 0;

  uint8_t digit_index           = 0;

  uint8_t exponent_sign         = 0;

  uint8_t is_indeterminate      = 0;

  uint8_t is_infinite           = 0;

  uint8_t is_not_a_number       = 0;

  uint8_t is_negative           = 0;

  uint8_t number_of_characters  = 0;

  double exponent_value         = 0.0;

  double value_float            = 0.0;

  if( utf8_string == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-8 string.",

     function );

    return( -1 );

  }

  if( utf8_string_size > (size_t) SSIZE_MAX )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid UTF-8 string size value exceeds maximum.",

     function );

    return( -1 );

  }

  if( utf8_string_index == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-8 string index.",

     function );

    return( -1 );

  }

  safe_utf8_string_index = *utf8_string_index;

  is_negative = (uint8_t) ( value_32bit >> 31 );

  if( is_negative != 0 )

  {

    value_32bit &= ~( (uint32_t) 1 << 31 );

  }

  if( value_32bit == 0x7f800000UL )

  {

    is_infinite = 1;

  }

  else if( ( is_negative != 0 )

        && ( value_32bit == 0x7fc00000UL ) )

  {

    is_indeterminate = 1;

  }

  else if( ( value_32bit >= 0x7f800001UL )

        && ( value_32bit <= 0x7fffffffUL ) )

  {

    is_not_a_number = 1;

  }

  else if( value_32bit != 0 )

  {

    value_float32.integer = value_32bit;

    value_float           = (double) value_float32.floating_point;

    exponent2 = (int16_t) ( value_32bit >> 23 );

    if( exponent2 == 0 )

    {

      exponent2 = -126;

    }

    else

    {

      exponent2 -= 127;

    }

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    number_of_characters = 4;

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      number_of_characters = 15;

    }

    else

    {

      number_of_characters = 14;

    }

  }

  if( ( number_of_characters > utf8_string_size )

   || ( safe_utf8_string_index > ( utf8_string_size - number_of_characters ) ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_TOO_SMALL,

     "%s: invalid UTF-8 string size value too small.",

     function );

    return( -1 );

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'I';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'n';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'd';

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'I';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'n';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'f';

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'N';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'a';

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'N';

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      utf8_string[ safe_utf8_string_index++ ] = (uint8_t) '-';

    }

    if( exponent2 < 0 )

    {

      exponent_sign = (uint8_t) '-';

      exponent2    *= -1;

    }

    else

    {

      exponent_sign = (uint8_t) '+';

    }

    exponent_value = 1.0;

    exponent10     = 0;

    while( exponent2 > 0 )

    {

      exponent_value *= 2;

      exponent2--;

      if( exponent_value >= 10.0 )

      {

        exponent_value /= 10.0;

        exponent10++;

        if( exponent_sign == (uint8_t) '-' )

        {

          value_float *= 10.0;

        }

        else

        {

          value_float /= 10.0;

        }

      }

    }

    if( value_float != 0.0 )

    {

      while( ( value_float < 1.0 )

          || ( value_float >= 10.0 ) )

      {

        exponent10++;

        if( exponent_sign == (uint8_t) '-' )

        {

          value_float *= 10;

        }

        else

        {

          value_float /= 10;

        }

      }

    }

    for( digit_index = 0;

         digit_index < 7;

         digit_index++ )

    {

      value_fraction *= 10;

      value_fraction += (uint8_t) value_float;

      value_float -= (uint8_t) value_float;

      value_float *= 10.0;

    }

    if( value_float >= 5.0 )

    {

      value_fraction += 1;

    }

    divider = 1000000;

    for( digit_index = 0;

         digit_index < 7;

         digit_index++ )

    {

      utf8_string[ safe_utf8_string_index++ ] = (uint8_t) '0' + (uint8_t) ( value_fraction / divider );

      if( digit_index == 0 )

      {

        utf8_string[ safe_utf8_string_index++ ] = (uint8_t) '.';

      }

      value_fraction %= divider;

      divider        /= 10;

    }

    utf8_string[ safe_utf8_string_index++ ] = (uint8_t) 'e';

    utf8_string[ safe_utf8_string_index++ ] = exponent_sign;

    divider = 100;

    for( digit_index = 0;

         digit_index < 3;

         digit_index++ )

    {

      utf8_string[ safe_utf8_string_index++ ] = (uint8_t) '0' + (uint8_t) ( exponent10 / divider );

      exponent10 %= divider;

      divider    /= 10;

    }

  }

  utf8_string[ safe_utf8_string_index++ ] = 0;

  *utf8_string_index = safe_utf8_string_index;

  return( 1 );

}

/* Copies a 32-bit floating point to an UTF-16 string

 * The string size should include the end of string character

 * Returns 1 if successful or -1 on error

 */

int libfwevt_float32_copy_to_utf16_string_with_index(

     uint32_t value_32bit,

     uint16_t *utf16_string,

     size_t utf16_string_size,

     size_t *utf16_string_index,

     libcerror_error_t **error )

{

  byte_stream_float32_t value_float32;

  static char *function          = "libfwevt_float32_copy_to_utf16_string_with_index";

  size_t safe_utf16_string_index = 0;

  uint32_t divider               = 0;

  uint32_t value_fraction        = 0;

  uint16_t exponent_sign         = 0;

  int16_t exponent10             = 0;

  int16_t exponent2              = 0;

  uint8_t digit_index            = 0;

  uint8_t is_indeterminate       = 0;

  uint8_t is_infinite            = 0;

  uint8_t is_not_a_number        = 0;

  uint8_t is_negative            = 0;

  uint8_t number_of_characters   = 0;

  double exponent_value          = 0.0;

  double value_float             = 0.0;

  if( utf16_string == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-16 string.",

     function );

    return( -1 );

  }

  if( utf16_string_size > (size_t) SSIZE_MAX )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid UTF-16 string size value exceeds maximum.",

     function );

    return( -1 );

  }

  if( utf16_string_index == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-16 string index.",

     function );

    return( -1 );

  }

  safe_utf16_string_index = *utf16_string_index;

  is_negative = (uint8_t) ( value_32bit >> 31 );

  if( is_negative != 0 )

  {

    value_32bit &= ~( (uint32_t) 1 << 31 );

  }

  if( value_32bit == 0x7f800000UL )

  {

    is_infinite = 1;

  }

  else if( ( is_negative != 0 )

        && ( value_32bit == 0x7fc00000UL ) )

  {

    is_indeterminate = 1;

  }

  else if( ( value_32bit >= 0x7f800001UL )

        && ( value_32bit <= 0x7fffffffUL ) )

  {

    is_not_a_number = 1;

  }

  else if( value_32bit != 0 )

  {

    value_float32.integer = value_32bit;

    value_float           = (double) value_float32.floating_point;

    exponent2 = (int16_t) ( value_32bit >> 23 );

    if( exponent2 == 0 )

    {

      exponent2 = -126;

    }

    else

    {

      exponent2 -= 127;

    }

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    number_of_characters = 4;

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      number_of_characters = 15;

    }

    else

    {

      number_of_characters = 14;

    }

  }

  if( ( number_of_characters > utf16_string_size )

   || ( safe_utf16_string_index > ( utf16_string_size - number_of_characters ) ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_TOO_SMALL,

     "%s: invalid UTF-16 string size value too small.",

     function );

    return( -1 );

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'I';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'n';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'd';

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'I';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'n';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'f';

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'N';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'a';

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'N';

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      utf16_string[ safe_utf16_string_index++ ] = (uint16_t) '-';

    }

    if( exponent2 < 0 )

    {

      exponent_sign = (uint16_t) '-';

      exponent2    *= -1;

    }

    else

    {

      exponent_sign = (uint16_t) '+';

    }

    exponent_value = 1.0;

    exponent10     = 0;

    while( exponent2 > 0 )

    {

      exponent_value *= 2;

      exponent2--;

      if( exponent_value >= 10.0 )

      {

        exponent_value /= 10.0;

        exponent10++;

        if( exponent_sign == (uint16_t) '-' )

        {

          value_float *= 10.0;

        }

        else

        {

          value_float /= 10.0;

        }

      }

    }

    if( value_float != 0.0 )

    {

      while( ( value_float < 1.0 )

          || ( value_float >= 10.0 ) )

      {

        exponent10++;

        if( exponent_sign == (uint16_t) '-' )

        {

          value_float *= 10;

        }

        else

        {

          value_float /= 10;

        }

      }

    }

    for( digit_index = 0;

         digit_index < 7;

         digit_index++ )

    {

      value_fraction *= 10;

      value_fraction += (uint8_t) value_float;

      value_float -= (uint8_t) value_float;

      value_float *= 10.0;

    }

    if( value_float >= 5.0 )

    {

      value_fraction += 1;

    }

    divider = 1000000;

    for( digit_index = 0;

         digit_index < 7;

         digit_index++ )

    {

      utf16_string[ safe_utf16_string_index++ ] = (uint16_t) '0' + (uint16_t) ( value_fraction / divider );

      if( digit_index == 0 )

      {

        utf16_string[ safe_utf16_string_index++ ] = (uint16_t) '.';

      }

      value_fraction %= divider;

      divider        /= 10;

    }

    utf16_string[ safe_utf16_string_index++ ] = (uint16_t) 'e';

    utf16_string[ safe_utf16_string_index++ ] = exponent_sign;

    divider = 100;

    for( digit_index = 0;

         digit_index < 3;

         digit_index++ )

    {

      utf16_string[ safe_utf16_string_index++ ] = (uint16_t) '0' + (uint16_t) ( exponent10 / divider );

      exponent10 %= divider;

      divider    /= 10;

    }

  }

  utf16_string[ safe_utf16_string_index++ ] = 0;

  *utf16_string_index = safe_utf16_string_index;

  return( 1 );

}

/* Deterimes the size of the string of a 64-bit floating point

 * The string size includes the end of string character

 * Returns 1 if successful or -1 on error

 */

int libfwevt_float64_get_string_size(

     uint64_t value_64bit,

     size_t *string_size,

     libcerror_error_t **error )

{

  static char *function        = "libfwevt_float64_get_string_size";

  uint8_t is_indeterminate     = 0;

  uint8_t is_infinite          = 0;

  uint8_t is_not_a_number      = 0;

  uint8_t is_negative          = 0;

  uint8_t number_of_characters = 0;

  if( string_size == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid string size.",

     function );

    return( -1 );

  }

  is_negative = (uint8_t) ( value_64bit >> 63 );

  if( is_negative != 0 )

  {

    value_64bit &= ~( (uint64_t) 1 << 63 );

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  if( value_64bit == 0x7ff0000000000000UL )

#else

  if( value_64bit == 0x7ff0000000000000ULL )

#endif

  {

    is_infinite = 1;

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  else if( ( is_negative != 0 )

        && ( value_64bit == 0x7ff8000000000000UL ) )

#else

  else if( ( is_negative != 0 )

        && ( value_64bit == 0x7ff8000000000000ULL ) )

#endif

  {

    is_indeterminate = 1;

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  else if( ( value_64bit >= 0x7ff0000000000001UL )

        && ( value_64bit <= 0x7fffffffffffffffUL ) )

#else

  else if( ( value_64bit >= 0x7ff0000000000001ULL )

        && ( value_64bit <= 0x7fffffffffffffffULL ) )

#endif

  {

    is_not_a_number = 1;

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    number_of_characters = 4;

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      number_of_characters = 15;

    }

    else

    {

      number_of_characters = 14;

    }

  }

  *string_size = number_of_characters;

  return( 1 );

}

/* Copies a 64-bit floating point to an UTF-8 string

 * The string size should include the end of string character

 * Returns 1 if successful or -1 on error

 */

int libfwevt_float64_copy_to_utf8_string_with_index(

     uint64_t value_64bit,

     uint8_t *utf8_string,

     size_t utf8_string_size,

     size_t *utf8_string_index,

     libcerror_error_t **error )

{

  byte_stream_float64_t value_float64;

  static char *function         = "libfwevt_float64_copy_to_utf8_string_with_index";

  size_t safe_utf8_string_index = 0;

  uint64_t divider              = 0;

  uint64_t value_fraction       = 0;

  int16_t exponent10            = 0;

  int16_t exponent2             = 0;

  uint8_t digit_index           = 0;

  uint8_t exponent_sign         = 0;

  uint8_t is_indeterminate      = 0;

  uint8_t is_infinite           = 0;

  uint8_t is_not_a_number       = 0;

  uint8_t is_negative           = 0;

  uint8_t number_of_characters  = 0;

  double exponent_value         = 0.0;

  double value_float            = 0.0;

  if( utf8_string == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-8 string.",

     function );

    return( -1 );

  }

  if( utf8_string_size > (size_t) SSIZE_MAX )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid UTF-8 string size value exceeds maximum.",

     function );

    return( -1 );

  }

  if( utf8_string_index == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid UTF-8 string index.",

     function );

    return( -1 );

  }

  safe_utf8_string_index = *utf8_string_index;

  is_negative = (uint8_t) ( value_64bit >> 63 );

  if( is_negative != 0 )

  {

    value_64bit &= ~( (uint64_t) 1 << 63 );

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  if( value_64bit == 0x7ff0000000000000UL )

#else

  if( value_64bit == 0x7ff0000000000000ULL )

#endif

  {

    is_infinite = 1;

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  else if( ( is_negative != 0 )

        && ( value_64bit == 0x7ff8000000000000UL ) )

#else

  else if( ( is_negative != 0 )

        && ( value_64bit == 0x7ff8000000000000ULL ) )

#endif

  {

    is_indeterminate = 1;

  }

#if defined( __BORLANDC__ ) && ( __BORLANDC__ < 0x0560 )

  else if( ( value_64bit >= 0x7ff0000000000001UL )

        && ( value_64bit <= 0x7fffffffffffffffUL ) )

#else

  else if( ( value_64bit >= 0x7ff0000000000001ULL )

        && ( value_64bit <= 0x7fffffffffffffffULL ) )

#endif

  {

    is_not_a_number = 1;

  }

  else if( value_64bit != 0 )

  {

    value_float64.integer = value_64bit;

    value_float           = (double) value_float64.floating_point;

    exponent2 = (int16_t) ( value_64bit >> 52 );

    if( exponent2 == 0 )

    {

      exponent2 = -1023;

    }

    else

    {

      exponent2 -= 1023;

    }

  }

  if( is_indeterminate != 0 )

  {

    /* "Ind" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_infinite != 0 )

  {

    /* "Inf" + end-of-string character */

    number_of_characters = 4;

  }

  else if( is_not_a_number != 0 )

  {

    /* "Nan" + end-of-string character */

    number_of_characters = 4;

  }

  else

  {

    /* "[-]0.000000e[+-]000" + end-of-string character */

    if( is_negative != 0 )

    {

      number_of_characters = 15;

    }

    else

    {

      number_of_characters = 14;

    }

  }

  if( ( number_of_characters > utf8_string_size )