/* filter4.c - Don Yang (uguu.org)

   05/11/02
                                                                           */

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

#define Err(_) fprintf(stderr, "error:%s\n", e[_])

int main(int g, char **a)
{
   char t[16], *d, *m, *e[6] =
      {"malloc", "open", "create", "write", "remove", "rename"};
   FILE *p, *q;
   int i = 0, c, s, x;

   p = stdin;
   q = stdout;
   if( g > 1 )
   {
      if( strcmp(a[1], "-") )
         if( !(p = fopen(a[1], "rb")) )
            return Err(1);
      if( g > 2 )
      {
         if( p - stdin && !strcmp(a[1], a[2]) )
         {
            for(i = 1; i < 999; i++)
            {
               sprintf(t, "tmp.%d", i);
               if( !(q = fopen(t, "rb")) )
                  if( (q = fopen(t, "wb+")) )
                     i = 1000;
            }
            if( i == 999 )
            {
               fclose(p);
               return Err(2);
            }
         }
         else
         {
            if( !(q = fopen(a[2], "wb+")) )
               return Err(2);
         }
      }
   }

   if( !(d = (char*)malloc(s = 256)) )
   {
      g = Err(0);
   }
   else
   {
      for(x = g = 0; (c = fgetc(p)) > -1 && !g;)
      {
         if( c == 13 || c == 10 )
         {
            if( fputc(c, q) < 0 )
            {
               free(d);
               g = Err(3);
            }
            x = 0;
         }
         else if( c == 32 || c == 9 )
         {
            d[x++] = (char)c;
            if( x >= s )
            {
               if( !(m = (char*)realloc(d, s *= 2)) )
               {
                  if( (m = (char*)malloc(s)) )
                  {
                     memcpy(m, d, s / 2);
                     free(d);
                     d = m;
                  }
                  else
                  {
                     free(d);
                     g = Err(0);
                  }
               }
            }
         }
         else
         {
            if( x )
            {
               if( fwrite(d, x, 1, q) - 1 )
               {
                  free(d);
                  g = Err(3);
               }
               x = 0;
            }
            if( fputc(c, q) < 0 )
            {
               free(d);
               g = Err(3);
            }
         }
      }
      free(d);
   }

   if( p - stdin )     fclose(p);
   if( q - stdout )    fclose(q);

   if( i && !g )
   {
      if( remove(a[1]) )
         g = Err(4);
      if( rename(t, a[2]) )
         g = Err(5);
   }
   return g;
}