# include <ctype.h>
# include <stdio.h>
# include <stdlib.h>
# include <string.h>

# include "ppc_fetch_line.h"

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

char *trim_line ( char *s )

/******************************************************************************/
{
  char *t;
/*
  Increase S to location of first nonwhitespace character.
*/
  while ( isspace ( *s ) )
  {
    s++;
  }
/*
  T begins at S, but advances until it reaches a null or #.
*/
  t = s;
  while ( *t != '\0' && *t != '#' )
  {
    t++;
  }
  if ( *t == '#' )
  {
    *t = '\0';
  }
/*
  Replace each trailing whitespace character by null.
*/
  if ( s < t )
  {
    while ( 1 )
    {
      t--;
      if ( ! isspace ( *t ) )
      {
        break;
      }
      *t = '\0';
    }
  }
  return s;
}

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

char *fetch_line ( char *buf, int buflen, FILE *stream, int *lineno )

/******************************************************************************/
/*
  Purpose:

    fetch_line() returns a line from a text file.

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    06 September 2023

  Author:

    Original C version by Rouben Rostamian.
    This version by John Burkardt.

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5

  Input:

  Output:
*/
{
  char *s;

  if ( fgets ( buf, buflen, stream ) == NULL )
  {
    return NULL;
  }

  (*lineno)++;

  if ( buf[ strlen(buf) - 1 ] != '\n' )
  {
    fprintf ( stderr, "\n" );
    fprintf ( stderr, "ppc_fetch_line(): Fatal error!\n" );
    fprintf ( stderr, "  Input line %d too long\n", *lineno );
    fprintf ( stderr, "  for buffer size %d\n", buflen ); 
    exit ( EXIT_FAILURE );
  }
  
  s = trim_line ( buf );

  if ( *s != '\0' )
  {
    return s;
  }
  else
  {
    return fetch_line ( buf, buflen, stream, lineno );
  }
}