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/*
* Copyright (c) 1990, 2007 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* and/or other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/* No user fns here. Pesch 15apr92. */
#define _DEFAULT_SOURCE
#include <_ansi.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/unistd.h>
#include "local.h"
#define _DEFAULT_ASPRINTF_BUFSIZE 64
/*
* Allocate a file buffer, or switch to unbuffered I/O.
* Per the ANSI C standard, ALL tty devices default to line buffered.
*
* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
* optimization) right after the _fstat() that finds the buffer size.
*/
void
_smakebuf (
register FILE *fp)
{
register void *p;
int flags;
size_t size;
int couldbetty;
if (fp->_flags & __SNBF)
{
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
return;
}
flags = _swhatbuf ( fp, &size, &couldbetty);
if ((p = malloc (size)) == NULL)
{
if (!(fp->_flags & __SSTR))
{
fp->_flags = (fp->_flags & ~__SLBF) | __SNBF;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
}
}
else
{
fp->_flags |= __SMBF;
fp->_bf._base = fp->_p = (unsigned char *) p;
fp->_bf._size = size;
if (couldbetty && isatty (fp->_file))
fp->_flags = (fp->_flags & ~__SNBF) | __SLBF;
fp->_flags |= flags;
}
}
/*
* Internal routine to determine `proper' buffering for a file.
*/
int
_swhatbuf (
FILE *fp,
size_t *bufsize,
int *couldbetty)
{
#ifdef _FSEEK_OPTIMIZATION
const int snpt = __SNPT;
#else
const int snpt = 0;
#endif
#ifdef __USE_INTERNAL_STAT64
struct stat64 st;
if (fp->_file < 0 || fstat64 (fp->_file, &st) < 0)
#else
struct stat st;
if (fp->_file < 0 || fstat (fp->_file, &st) < 0)
#endif
{
*couldbetty = 0;
/* Check if we are be called by asprintf family for initial buffer. */
if (fp->_flags & __SMBF)
*bufsize = _DEFAULT_ASPRINTF_BUFSIZE;
else
*bufsize = BUFSIZ;
return (0);
}
/* could be a tty iff it is a character device */
*couldbetty = S_ISCHR(st.st_mode);
#ifdef HAVE_BLKSIZE
if (st.st_blksize > 0)
{
/*
* Optimise fseek() only if it is a regular file. (The test for
* __sseek is mainly paranoia.) It is safe to set _blksize
* unconditionally; it will only be used if __SOPT is also set.
*/
*bufsize = st.st_blksize;
fp->_blksize = st.st_blksize;
return ((st.st_mode & S_IFMT) == S_IFREG ? __SOPT : snpt);
}
#endif
*bufsize = BUFSIZ;
return (snpt);
}
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