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/* Conversion utility CR/LF -> NL */
/* multiple files, in place, restores write date */
/* Bruno Haible 23.1.1994 */
/* Make: gcc -O2 -fomit-frame-pointer -N -o fromdos fromdos.c */
#include <sys/types.h>
#include <unistd.h> /* open, read, write, close, lseek, ftruncate */
#include <fcntl.h> /* O_RDONLY, O_RDWR */
#include <sys/stat.h> /* fstat */
#include <sys/time.h> /* struct timeval, utimes */
#include <errno.h> /* EINTR, perror */
#define CR 13
#define LF 10
#define NL 10
#define BUFLEN 4096
int full_read (int fd, char* buf, size_t nbyte);
int full_write (int fd, char* buf, size_t nbyte);
int main (int argc, char* argv[])
{ int i;
for (i=1; i<argc; i++)
{ char* filename = argv[i];
/* open filename twice so that there is no need to lseek */
int rfd = open(filename,O_RDONLY);
if (rfd<0) { perror(filename); goto next; }
{struct stat statbuf;
if (fstat(rfd,&statbuf)<0) { perror(filename); goto next; }
{ int wfd = open(filename,O_RDWR);
if (wfd<0) { perror(filename); close(rfd); goto next; }
{ char buffer[BUFLEN];
char* bufend = &buffer[BUFLEN];
register char* srcptr = &buffer[0];
register char* destptr;
while (1) /* srcptr is either &buffer[0] or &buffer[1] here */
{ register int count = full_read(rfd,srcptr,bufend-srcptr);
if (count < 0)
{ perror(filename); close(wfd); close(rfd); goto next; }
if (count == 0) break; /* EOF */
count += (srcptr - &buffer[0]);
destptr = srcptr = &buffer[0];
do /* srcptr + count remains constant, destptr<=srcptr, count>0 */
{ if (*srcptr == CR)
{ if (count > 1)
{ if (srcptr[1] == LF)
{ *destptr++ = NL; srcptr += 2; count -= 2; }
else
{ *destptr++ = *srcptr++; count--; }
}
else
break; /* CR at the end of the buffer -> finish loop */
}
else
{ *destptr++ = *srcptr++; count--; }
}
while (count > 0);
/* count = 0 or = 1 here */
if (full_write(wfd,buffer,destptr-buffer) < 0)
{ perror(filename); close(wfd); close(rfd); goto next; }
if (count > 0)
{ buffer[0] = *srcptr; srcptr = &buffer[1]; }
else
{ srcptr = &buffer[0]; }
}
if (srcptr!=buffer)
{ if (full_write(wfd,buffer,srcptr-buffer) < 0)
{ perror(filename); close(wfd); close(rfd); goto next; }
}
}
{ off_t length = lseek(wfd,0,SEEK_CUR);
if (length < 0)
{ perror(filename); close(wfd); close(rfd); goto next; }
if (ftruncate(wfd,length) < 0)
{ perror(filename); close(wfd); close(rfd); goto next; }
}
close(wfd);
}
close(rfd);
/* reset the access and modification times */
{ struct timeval tv[2];
tv[0].tv_sec = statbuf.st_atime; tv[0].tv_usec = 0;
tv[1].tv_sec = statbuf.st_mtime; tv[1].tv_usec = 0;
if (utimes(filename,tv) < 0) { perror(filename); goto next; }
}
}
next: ;
}
exit(0);
}
/* On POSIX systems, read() and write() may return partial results without
failing. Redefine the functions read() and write() such that they retry
whenever a partial result is received or the system call is interrupted
by a signal.
The function full_read and full_write behave like BSD read() and write():
on success, they return nbyte;
on EOF, they return 0;
on failure, they return a negative value and set errno.
*/
int full_read (fd, buf, nbyte)
int fd;
char *buf;
size_t nbyte;
{
register int retval;
size_t done = 0;
while (nbyte > 0)
{
retval = read (fd, buf, nbyte);
if (retval == 0)
break;
else if (retval < 0)
{
#ifdef EINTR
if (errno != EINTR)
#endif
return retval;
}
else
{
buf += retval;
done += (size_t) retval;
nbyte -= (size_t) retval;
}
}
return done;
}
int full_write (fd, buf, nbyte)
int fd;
char *buf;
size_t nbyte;
{
register int retval;
size_t done = 0;
while (nbyte > 0)
{
retval = write (fd, buf, nbyte);
if (retval == 0)
break;
else if (retval < 0)
{
#ifdef EINTR
if (errno != EINTR)
#endif
return retval;
}
else
{
buf += retval;
done += (size_t) retval;
nbyte -= (size_t) retval;
}
}
return done;
}
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