/*----------------------------------------------------------+
 | stripcr.c -- 5/15/1992 public domain                     |
 |           by Alex Matulich, Unicorn Research Corporation |
 | Strip CR characters from a text file, leaving only LF's. |
 +----------------------------------------------------------*/
#define OUTBUFSIZ 16384
                                                
#include <stdio.h>
#include <stdlib.h>  /* for malloc() */
#define CR '\x0D'

unsigned short replace, bufptr = 0;
signed char *buf = NULL;
FILE *infile, *outfile;
long inpos = 0L, outpos = 0L;       /* file position trackers */

int writebuf(void);

void main(int argc, char *argv[])
{
unsigned short err = 0;
signed char ch;

if (argc != 3 && argc != 2) {
   fputs("StripCR by Unicorn Research Corporation\nStrip CR characters from text files that use the CR+LF combination.\n\nUsage:  StripCR infile [outfile]\n\nIf outfile is omitted, then infile will be replaced.\n", stdout);
   return;
   }
if((infile = fopen( argv[1], (replace = (argc == 2)) ? "rb+" : "rb" )) == NULL) {
   fputs("Could not open input file.\n", stdout);
   return;
   }
if (replace)
   outfile = infile;
else if ((outfile = fopen( argv[2], "wb" )) == NULL) {
   fputs("Could not open output file.\n", stdout);
   fclose(infile);
   return;
   }
if ((buf = (signed char *)malloc(OUTBUFSIZ)) == NULL) {
   fputs("Not enough memory!\n", stdout);
   goto cleanup;
   }

while ((ch = fgetc(infile)) != EOF) {
   ++inpos;          /* position of next character in input file */
   if (ch != CR) {
      buf[bufptr++] = ch;
      if (bufptr == OUTBUFSIZ) if (err = writebuf()) break;
      }
   }

if (!err && bufptr) err = writebuf();
if (err == 1)
   fputs("Error writing output file.\n", stdout);
else if (err == 2)
   fputs("Error reading input file.\n", stdout);
else if (replace) {
   fseek(outfile, outpos, 0);
   fputc('\x1A', outfile);  /* output a ctrl-Z */
   fputs(argv[1], stdout);
   fputs(" is now stripped of CR's.\nDelete all text past the ctrl-Z character.\n", stdout);
   }
else {
   fputs("Stripped file ", stdout);
   fputs(argv[2], stdout);
   fputs(" successfully created.\n", stdout);
   }
cleanup:
free(buf);
fclose(infile);
if (!replace) fclose(outfile);
}


/* write the buffer to the output file, when full or when done */
int writebuf()
{
unsigned short i = 0;
if (replace) if (fseek(outfile, outpos, 0)) return 1;
while (i < bufptr)
   if (fputc(buf[i++], outfile) == EOF) return 1;
outpos += bufptr;
if (replace) if (fseek(infile, inpos, 0)) return 2;
bufptr = 0;
return 0;
}