Line data    Source code

       1             : /* Retrieve information about a FILE stream.
       2             :    Copyright (C) 2007-2008 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             : 
      22             : size_t
      23         666 : freadahead (FILE *fp)
      24             : {
      25             : #if defined _IO_ferror_unlocked || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Linux libc5 */
      26         666 :   if (fp->_IO_write_ptr > fp->_IO_write_base)
      27           0 :     return 0;
      28         666 :   return (fp->_IO_read_end - fp->_IO_read_ptr)
      29         666 :          + (fp->_flags & _IO_IN_BACKUP ? fp->_IO_save_end - fp->_IO_save_base :
      30             :             0);
      31             : #elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
      32             : # if defined __NetBSD__ || defined __OpenBSD__
      33             :   struct __sfileext
      34             :     {
      35             :       struct  __sbuf _ub; /* ungetc buffer */
      36             :       /* More fields, not relevant here.  */
      37             :     };
      38             : # define HASUB(fp) (((struct __sfileext *) (fp)->_ext._base)->_ub._base != NULL)
      39             : # else
      40             : # define HASUB(fp) ((fp)->_ub._base != NULL)
      41             : # endif
      42             :   if ((fp->_flags & __SWR) != 0 || fp->_r < 0)
      43             :     return 0;
      44             :   return fp->_r
      45             :          + (HASUB (fp) ? fp->_ur : 0);
      46             : #elif defined __EMX__               /* emx+gcc */
      47             :   if ((fp->_flags & _IOWRT) != 0)
      48             :     return 0;
      49             :   /* Note: fp->_ungetc_count > 0 implies fp->_rcount <= 0,
      50             :            fp->_ungetc_count = 0 implies fp->_rcount >= 0.  */
      51             :   /* equivalent to
      52             :      (fp->_ungetc_count == 0 ? fp->_rcount : fp->_ungetc_count - fp->_rcount) */
      53             :   return (fp->_rcount > 0 ? fp->_rcount : fp->_ungetc_count - fp->_rcount);
      54             : #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */
      55             : # if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */
      56             : #  define fp_ ((struct { unsigned char *_ptr; \
      57             :                          unsigned char *_base; \
      58             :                          unsigned char *_end; \
      59             :                          long _cnt; \
      60             :                          int _file; \
      61             :                          unsigned int _flag; \
      62             :                        } *) fp)
      63             :   if ((fp_->_flag & _IOWRT) != 0)
      64             :     return 0;
      65             :   return fp_->_cnt;
      66             : # else
      67             : #  if defined _SCO_DS               /* OpenServer */
      68             : #   define _flag __flag
      69             : #   define _cnt __cnt
      70             : #  endif
      71             :   if ((fp->_flag & _IOWRT) != 0)
      72             :     return 0;
      73             :   return fp->_cnt;
      74             : # endif
      75             : #elif defined __UCLIBC__            /* uClibc */
      76             : # ifdef __STDIO_BUFFERS
      77             :   if (fp->__modeflags & __FLAG_WRITING)
      78             :     return 0;
      79             :   return (fp->__bufread - fp->__bufpos)
      80             :          + (fp->__modeflags & __FLAG_UNGOT ? 1 : 0);
      81             : # else
      82             :   return 0;
      83             : # endif
      84             : #elif defined __QNX__               /* QNX */
      85             :   if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
      86             :     return 0;
      87             :   /* fp->_Buf <= fp->_Next <= fp->_Rend,
      88             :      and fp->_Rend may be overridden by fp->_Rsave. */
      89             :   return ((fp->_Rsave ? fp->_Rsave : fp->_Rend) - fp->_Next)
      90             :          + (fp->_Mode & 0x4000 /* _MBYTE */
      91             :             ? (fp->_Back + sizeof (fp->_Back)) - fp->_Rback
      92             :             : 0);
      93             : #else
      94             :  #error "Please port gnulib freadahead.c to your platform! Look at the definition of fflush, fread, ungetc on your system, then report this to bug-gnulib."
      95             : #endif
      96             : }