1/* Retrieve information about a FILE stream. 2 Copyright (C) 2007 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17#include <config.h> 18 19/* Specification. */ 20#include "freadahead.h" 21 22size_t 23freadahead (FILE *fp) 24{ 25#if defined _IO_ferror_unlocked /* GNU libc, BeOS */ 26 if (fp->_IO_write_ptr > fp->_IO_write_base) 27 return 0; 28 return fp->_IO_read_end - fp->_IO_read_ptr; 29#elif defined __sferror /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */ 30 if ((fp->_flags & __SWR) != 0 || fp->_r < 0) 31 return 0; 32 return fp->_r; 33#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */ 34# if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */ 35# define fp_ ((struct { unsigned char *_ptr; \ 36 unsigned char *_base; \ 37 unsigned char *_end; \ 38 long _cnt; \ 39 int _file; \ 40 unsigned int _flag; \ 41 } *) fp) 42 if ((fp_->_flag & _IOWRT) != 0) 43 return 0; 44 return fp_->_cnt; 45# else 46 if ((fp->_flag & _IOWRT) != 0) 47 return 0; 48 return fp->_cnt; 49# endif 50#elif defined __UCLIBC__ /* uClibc */ 51# ifdef __STDIO_BUFFERS 52 if (fp->__modeflags & __FLAG_WRITING) 53 return 0; 54 return fp->__bufread - fp->__bufpos; 55# else 56 return 0; 57# endif 58#elif defined __QNX__ /* QNX */ 59 if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0) 60 return 0; 61 /* fp->_Buf <= fp->_Next <= fp->_Rend */ 62 return fp->_Rend - fp->_Next; 63#else 64 #error "Please port gnulib freadahead.c to your platform! Look at the definition of fflush, fread on your system, then report this to bug-gnulib." 65#endif 66} 67