prog/c/delete-trailing-ws.c

/* This file deletes trailing white space in a file */

#include <stdio.h>
#include <stdlib.h>
#include <argp.h>
#include <string.h>
enum boolean { NO, YES };
enum boolean i = NO;
enum boolean o = NO;
char fileName [128];
char outputFileName [128];

const char * argp_program_version = "0.1";
/* mail bug reports to */
const char * argp_program_bug_address = "jbranso@fastmail.com";

static const struct argp_option options [] =
  {
    {"input", 'i',  "FILE", 0, "delete the trailing whitespace in the file" },
    {"output", 'o', "FILE", 0, "output to save the file"},
    { 0 }
  };

//parse options
error_t argp_parser (int opt, char *arg, struct argp_state *state) {
  extern enum boolean bool;
  switch (opt)
    {
      // if this parser function is called on an option that it doesn't recognize, then don't do anything.
    default:
      return ARGP_ERR_UNKNOWN;
    case 'i':
      {
        i = YES;
        memcpy (fileName, arg, strlen (arg));
        break;
      }
    case 'o':
      {
        o = YES;
        memcpy (outputFileName, arg, strlen (arg));
        break;
      }
    }
  return 0;
}

struct argp argp =
  { options, argp_parser, 0, "Deletes trailing whitespace." };

int main (int argc, char **argv) {

  argp_parse (&argp, argc, argv, 0, 0, 0);

  if (fileName == 0) // make this check to see if the array has a string...
    return 0;

  FILE * inputFile = fopen(fileName, "r+");

  if (outputFileName == 0)
    return 0;

  FILE * outputFile = fopen(outputFileName, "w");
  //get getline ready
  const int MAX_LINE = 512;
  // this counts the number of white space in a file
  // if the file contents are "    a", then when getc returns 'a'
  // then whiteSpaceString is "    \0"
  char whiteSpaceString [MAX_LINE];
  whiteSpaceString[0] = '\0';

  // the length of each line
  size_t lengthOfLine;
  
  char c;
  
  while ( (c = getc(inputFile)) != EOF ) //get each character in file
    {
      // if c is non-white space, then print it
      if (ispunct (c) || isalnum (c))
        {
          // if current char in the string was preceeded by whitespace,
          // then print the white space, then the string
          // ie: "  e" => getc () =>  'e' --> print "  e"
          if (whiteSpaceString[0] != '\0') { 
            fputs(whiteSpaceString, outputFile); 
            whiteSpaceString[0] = '\0';
          }
          putc(c, outputFile);
        }
      else if (isblank (c))
        { //tab or space
          strcat (whiteSpaceString, &c); //use a custom function or macro
        }
      else //if (c == '\n')
        {
          whiteSpaceString[0] = '\0';
          putc(c, outputFile);
        }
    }
  fclose (inputFile);
  fclose (outputFile);
  // free the memory the compiled memory the regexp was using
  //regfree (&regexp);
  return 0;
}