97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/* No user fns here. Pesch 15apr92. */
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/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/unistd.h>
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#include "local.h"
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/*
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* Allocate a file buffer, or switch to unbuffered I/O.
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* Per the ANSI C standard, ALL tty devices default to line buffered.
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*
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* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
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* optimization) right after the _fstat() that finds the buffer size.
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*/
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void
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__smakebuf (fp)
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register FILE *fp;
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{
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register size_t size, couldbetty;
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register _PTR p;
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struct stat st;
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if (fp->_flags & __SNBF)
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{
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fp->_bf._base = fp->_p = fp->_nbuf;
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fp->_bf._size = 1;
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return;
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}
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if (fp->_file < 0 || _fstat_r (fp->_data, fp->_file, &st) < 0)
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{
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couldbetty = 0;
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size = BUFSIZ;
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/* do not try to optimise fseek() */
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fp->_flags |= __SNPT;
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}
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else
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{
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couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;
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#ifdef HAVE_BLKSIZE
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size = st.st_blksize <= 0 ? BUFSIZ : st.st_blksize;
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#else
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size = BUFSIZ;
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#endif
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/*
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* Optimize fseek() only if it is a regular file.
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* (The test for __sseek is mainly paranoia.)
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*/
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if ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek)
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{
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fp->_flags |= __SOPT;
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#ifdef HAVE_BLKSIZE
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fp->_blksize = st.st_blksize;
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#else
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fp->_blksize = 1024;
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#endif
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}
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else
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fp->_flags |= __SNPT;
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}
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if ((p = _malloc_r (fp->_data, size)) == NULL)
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{
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fp->_flags |= __SNBF;
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fp->_bf._base = fp->_p = fp->_nbuf;
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fp->_bf._size = 1;
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}
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else
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{
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fp->_data->__cleanup = _cleanup_r;
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fp->_flags |= __SMBF;
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fp->_bf._base = fp->_p = (unsigned char *) p;
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fp->_bf._size = size;
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if (couldbetty && isatty (fp->_file))
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fp->_flags |= __SLBF;
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}
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}
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