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/*
* Copyright (c) 1987, 1989 University of Maryland
* Department of Computer Science. All rights reserved.
* Permission to copy for any purpose is hereby granted
* so long as this copyright notice remains intact.
*/
/*
* SeekFile copies an input stdio file, if necessary, so that
* it produces a stdio file on which fseek() works properly.
* It returns NULL if this cannot be done; in that case, the
* input file is closed (or otherwise rendered worthless).
*
* CopyFile copies an input file unconditionally. (On non-Unix
* machines, it might `accidentally' not copy it.)
*
* On Unix machines, this means `if the input is a pipe or tty,
* copy it to a temporary file'. On other systems, all stdio files
* might happen to be seekable.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef __CYGWIN32__
#include <io.h>
#endif
#ifdef KPATHSEA
#include <kpathsea/c-fopen.h>
#endif
#include <stdio.h>
#include "types.h" /* for BSD_FILE_SYSTEM */
#include "seek.h"
#include "tempfile.h"
#include <errno.h>
#ifdef BSD_FILE_SYSTEM
#include <sys/param.h> /* want MAXBSIZE */
#else
#include <sys/types.h>
#endif
#include <sys/stat.h>
#ifndef KPATHSEA
long lseek();
char *malloc();
extern int errno;
#endif
/*
* Make and return a version of `f' on which fseek works (unconditionally).
* This code is somewhat Unix-specific.
*/
FILE *
CopyFile(FILE *f)
{
register int tf, n, ifd, w;
register char *p, *buf;
register int blksize;
#ifdef BSD_FILE_SYSTEM
struct stat st;
#endif
int e;
#ifdef MAXBSIZE
#define BSIZE MAXBSIZE
#else
#define BSIZE BUFSIZ
#endif
char stackbuf[BSIZE];
#if defined(WIN32) || defined(MSDOS) || defined(__CYGWIN32__)
int orig_fdmode;
#endif
const char *open_mode;
/* get a read/write temp file which will vanish when closed */
if ((tf = MakeRWTempFile(stackbuf)) < 0) {
e = errno;
(void) fclose(f);
errno = e;
return (NULL);
}
/* compute buffer size and choose buffer */
ifd = fileno(f);
buf = stackbuf;
blksize = sizeof stackbuf;
#ifdef BSD_FILE_SYSTEM
if (fstat(tf, &st) == 0 && st.st_blksize > blksize) {
/*
* The output block size is the important one,
* but the input block size is not irrelevant.
*
* This should actually compute the lcm, but we
* will rely on block sizes being powers of two
* (so that the larger is the lcm).
*/
blksize = st.st_blksize;
if (fstat(ifd, &st) == 0 && st.st_blksize > blksize)
blksize = st.st_blksize;
if ((buf = malloc((unsigned)blksize)) == NULL) {
buf = stackbuf;
blksize = sizeof stackbuf;
}
}
#endif
#if defined(WIN32) || defined(MSDOS) || defined(__CYGWIN32__)
/* make sure we open the temp file in the same mode that
the original handle was open. */
orig_fdmode = setmode(ifd, 0);
setmode(tf, orig_fdmode);
#endif
/* copy from input file to temp file */
(void) lseek(ifd, 0L, 0); /* paranoia */
while ((n = read(ifd, p = buf, blksize)) > 0) {
do {
if ((w = write(tf, p, n)) < 0) {
(void) close(tf);
(void) fclose(f);
return (NULL);
}
p += w;
} while ((n -= w) > 0);
}
e = errno; /* in case n < 0 */
if (buf != stackbuf)
free(buf);
if (n < 0) {
(void) close(tf);
(void) fclose(f);
errno = e;
return (NULL);
}
/* discard the input file, and rewind and open the temporary */
(void) fclose(f);
(void) lseek(tf, 0L, 0);
errno = 0;
#if defined(WIN32) || defined(MSDOS) || defined(__CYGWIN32__)
open_mode = orig_fdmode == O_BINARY ? FOPEN_RBIN_MODE : "r";
#else
open_mode = "r";
#endif
if ((f = fdopen(tf, open_mode)) == NULL) {
if (errno == 0)
e = EMFILE;
(void) close(tf);
errno = e;
}
return (f);
}
/*
* Copy an input file, but only if necessary.
*/
FILE *SeekFile(FILE *f)
{
int fd = fileno(f);
return (lseek(fd, 0L, 1) >= 0 && !isatty(fd) ? f : CopyFile(f));
}
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