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/* No user fns here. Pesch 15apr92. */
/*
* Copyright (c) 1990 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,
* advertising materials, and 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/unistd.h>
#include "local.h"
/*
* 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 (fp)
register FILE *fp;
{
register size_t size, couldbetty;
register _PTR p;
struct stat st;
if (fp->_flags & __SNBF)
{
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
return;
}
if (fp->_file < 0 || _fstat_r (fp->_data, fp->_file, &st) < 0)
{
couldbetty = 0;
size = BUFSIZ;
/* do not try to optimise fseek() */
fp->_flags |= __SNPT;
}
else
{
couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;
#ifdef HAVE_BLKSIZE
size = st.st_blksize <= 0 ? BUFSIZ : st.st_blksize;
#else
size = BUFSIZ;
#endif
/*
* Optimize fseek() only if it is a regular file.
* (The test for __sseek is mainly paranoia.)
*/
if ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek)
{
fp->_flags |= __SOPT;
#ifdef HAVE_BLKSIZE
fp->_blksize = st.st_blksize;
#else
fp->_blksize = 1024;
#endif
}
else
fp->_flags |= __SNPT;
}
if ((p = _malloc_r (fp->_data, size)) == NULL)
{
fp->_flags |= __SNBF;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
}
else
{
fp->_data->__cleanup = _cleanup_r;
fp->_flags |= __SMBF;
fp->_bf._base = fp->_p = (unsigned char *) p;
fp->_bf._size = size;
if (couldbetty && isatty (fp->_file))
fp->_flags |= __SLBF;
}
}
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