Annotation of GNUtools/libg++/libio/filedoalloc.c, revision 1.1

1.1     ! root        1: /* 
        !             2: Copyright (C) 1993 Free Software Foundation
        !             3: 
        !             4: This file is part of the GNU IO Library.  This library is free
        !             5: software; you can redistribute it and/or modify it under the
        !             6: terms of the GNU General Public License as published by the
        !             7: Free Software Foundation; either version 2, or (at your option)
        !             8: any later version.
        !             9: 
        !            10: This library is distributed in the hope that it will be useful,
        !            11: but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            12: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            13: GNU General Public License for more details.
        !            14: 
        !            15: You should have received a copy of the GNU General Public License
        !            16: along with GNU CC; see the file COPYING.  If not, write to
        !            17: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
        !            18: 
        !            19: As a special exception, if you link this library with files
        !            20: compiled with a GNU compiler to produce an executable, this does not cause
        !            21: the resulting executable to be covered by the GNU General Public License.
        !            22: This exception does not however invalidate any other reasons why
        !            23: the executable file might be covered by the GNU General Public License. */
        !            24: 
        !            25: /*
        !            26:  * Copyright (c) 1990 The Regents of the University of California.
        !            27:  * All rights reserved.
        !            28:  *
        !            29:  * Redistribution and use in source and binary forms are permitted
        !            30:  * provided that the above copyright notice and this paragraph are
        !            31:  * duplicated in all such forms and that any documentation,
        !            32:  * advertising materials, and other materials related to such
        !            33:  * distribution and use acknowledge that the software was developed
        !            34:  * by the University of California, Berkeley.  The name of the
        !            35:  * University may not be used to endorse or promote products derived
        !            36:  * from this software without specific prior written permission.
        !            37:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            38:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            39:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            40:  */
        !            41: 
        !            42: /* Modified for GNU iostream by Per Bothner 1991, 1992. */
        !            43: 
        !            44: #define _POSIX_SOURCE
        !            45: #include "libioP.h"
        !            46: #include <sys/types.h>
        !            47: #include <sys/stat.h>
        !            48: 
        !            49: /* If this function pointer is non-zero, we should call it.
        !            50:    It's supposed to make sure _IO_flush_all gets called on exit.
        !            51:    We call it from _IO_file_doallocate, since that is likely
        !            52:    to get called by any program that does buffered I/O. */
        !            53: void (*_IO_cleanup_registration_needed)();
        !            54: 
        !            55: /*
        !            56:  * Allocate a file buffer, or switch to unbuffered I/O.
        !            57:  * Per the ANSI C standard, ALL tty devices default to line buffered.
        !            58:  *
        !            59:  * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
        !            60:  * optimisation) right after the _fstat() that finds the buffer size.
        !            61:  */
        !            62: 
        !            63: int
        !            64: _IO_file_doallocate(fp)
        !            65:      register _IO_FILE *fp;
        !            66: {
        !            67:   register _IO_size_t size;
        !            68:   int couldbetty;
        !            69:   register char *p;
        !            70:   struct stat st;
        !            71: 
        !            72:   if (_IO_cleanup_registration_needed)
        !            73:     (*_IO_cleanup_registration_needed)();
        !            74:   
        !            75:   if (fp->_fileno < 0 || fp->_jumps->__stat(fp, &st) < 0)
        !            76:     {
        !            77:       couldbetty = 0;
        !            78:       size = _IO_BUFSIZ;
        !            79: #if 0
        !            80:       /* do not try to optimise fseek() */
        !            81:       fp->_flags |= __SNPT;
        !            82: #endif
        !            83:     }
        !            84:   else
        !            85:     {
        !            86:       couldbetty = S_ISCHR(st.st_mode);
        !            87: #if _IO_HAVE_ST_BLKSIZE
        !            88:       size = st.st_blksize <= 0 ? _IO_BUFSIZ : st.st_blksize;
        !            89: #else
        !            90:       size = _IO_BUFSIZ;
        !            91: #endif
        !            92:     }
        !            93: #ifdef USE_MALLOC_BUF
        !            94:   if ((p = malloc(size)) == NULL) {
        !            95:     unbuffered(1); /* FIXME */
        !            96:     /* fp->_bf._IO_buf_base = fp->_p = fp->_nbuf; */
        !            97:     /*         fp->_bf._size = 1; */
        !            98:     return EOF;
        !            99:   }
        !           100: #else
        !           101:   p = ALLOC_BUF(size);
        !           102: #endif
        !           103:   _IO_setb(fp, p, p+size, 1);
        !           104:   if (couldbetty && isatty(fp->_fileno))
        !           105:     fp->_flags |= _IO_LINE_BUF;
        !           106:   return 1;
        !           107: }

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