fileread.c
上传用户:xiejiait
上传日期:2007-01-06
资源大小:881k
文件大小:2k
- /* @(#)fileread.c 1.8 97/04/20 Copyright 1986 J. Schilling */
- /*
- * Copyright (c) 1986 J. Schilling
- */
- /*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; see the file COPYING. If not, write to
- * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
- */
- #include <stdio.h>
- #include <errno.h>
- #include "io.h"
- static char _readerr[] = "file_read_err";
- #ifdef HAVE_USG_STDIO
- int fileread(f, buf, len)
- register FILE *f;
- void *buf;
- int len;
- {
- int cnt;
- register int n;
- down2(f, _IOREAD, _IORW);
- if (f->_flag & _IONBF){
- cnt = _niread (fileno(f), buf, len);
- if (cnt < 0) {
- f->_flag |= _IOERR;
- if (!(my_flag(f) & _IONORAISE))
- raisecond(_readerr, 0L);
- }
- if (cnt == 0 && len)
- f->_flag |= _IOEOF;
- return cnt;
- }
- cnt = 0;
- while (len > 0) {
- if (f->_cnt <= 0){
- if (_filbuf(f) == EOF)
- break;
- f->_cnt++;
- f->_ptr--;
- }
- n = f->_cnt >= len ? len : f->_cnt;
- buf = (void *)movebytes (f->_ptr, buf, n);
- f->_ptr += n;
- f->_cnt -= n;
- cnt += n;
- len -= n;
- }
- if (!ferror(f))
- return cnt;
- if (!(my_flag(f) & _IONORAISE))
- raisecond(_readerr, 0L);
- return -1;
- }
- #else
- int fileread(f, buf, len)
- register FILE *f;
- void *buf;
- int len;
- {
- int cnt;
- down2(f, _IOREAD, _IORW);
- if (my_flag(f) & _IOUNBUF)
- return _niread(fileno(f), buf, len);
- cnt = fread(buf, 1, len, f);
- if (!ferror(f))
- return cnt;
- if (!(my_flag(f) & _IONORAISE))
- raisecond(_readerr, 0L);
- return -1;
- }
- #endif /* HAVE_USG_STDIO */