comment-remover.c

#include <stdio.h>
#define BUFFER_SIZE 2

enum FLAGS {NONE, SLASH, COMMENT1, COMMENTM, QUOTE1, QUOTE2, COMMENTM_STAR};
char buffer[BUFFER_SIZE];
int buff_pointer = 0;
void flush(char buff[]);
int state = NONE;
char t;

/* this is  a comment */
int main()
{
  while ((t = getchar()) != EOF)
  { 
    if (buff_pointer >= BUFFER_SIZE - 1)
      flush(buffer);
    if (state == NONE)
    { 
      buffer[buff_pointer++] = t;
      if (t=='/') 
        state = SLASH;
      if (t=='"')
        state = QUOTE2;
      if (t=='\'')
        state = QUOTE1;
    }
    else if (state == SLASH)
    {
      if (t=='*')
      {
        state = COMMENTM;
        buff_pointer--;
      }
      else if (t=='/')
      {
        state = COMMENT1;
        buff_pointer--;
      }
      else
      {
        state = NONE;
        buffer[buff_pointer++] = t;
      }
    }
    else if ((state == QUOTE1) && (t == '\''))
    {
      state = NONE;
      buffer[buff_pointer++] = t;
    }
    else if ((state == QUOTE2) && (t == '"'))
    {
      state = NONE;
      buffer[buff_pointer++] = t;
    }
    else if ((state == COMMENTM) && (t == '*'))
      state = COMMENTM_STAR;
    else if ((state == COMMENTM_STAR) && (t == '/'))
    {
      state = NONE;
      buff_pointer--;
    }
    else if (state == COMMENTM_STAR)
    {
      state = COMMENTM;
    }
    else if ((state == COMMENT1) && (t == '\n'))
    {
      state = NONE;
      buffer[buff_pointer++] = '\n';
    }
    else if (((state == QUOTE1) || (state == QUOTE2)) && (t == '\\'))
    {
      buffer[buff_pointer++] = t;
      buffer[buff_pointer++] = getchar(); // just go ahead and get the next one, since it's escaped
    }

    else if ((state == QUOTE1) || (state == QUOTE2))
    {
      buffer[buff_pointer++] = t; 
    }
  }
  flush(buffer);
}

/* this is a multi
 * lin
 * comment
 * */
// this is another comment
void flush(char buffer[])
{
  if (!(state == SLASH) && !(state == COMMENTM_STAR))
  {
    int j;
    for (j=0; j<buff_pointer; j++)
      putchar(buffer[j]);
    buff_pointer = 0;
  }
}

/* this is a  multi line
 * comment */