Re: closein, freadahead and ungetc

[Bruno Haible]

Eric Blake wrote:
> |   - freadahead keeps its signature but returns the total buffered bytes 
> count.

This implements it.

2008-03-09  Bruno Haible  <address@hidden>

        * lib/freadahead.h (freadahead): Document more precisely.
        * lib/freadahead.c (freadahead): When an ungetc is in effect, return
        the sum of both buffer sizes.
        * tests/test-freadahead.c (main): Also test behaviour after ungetc.
        * NEWS: Document the change.

*** lib/freadahead.h.orig       2008-03-10 01:57:39.000000000 +0100
--- lib/freadahead.h    2008-03-10 00:35:33.000000000 +0100
***************
*** 1,5 ****
  /* Retrieve information about a FILE stream.
!    Copyright (C) 2007 Free Software Foundation, Inc.
  
     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
--- 1,5 ----
  /* Retrieve information about a FILE stream.
!    Copyright (C) 2007-2008 Free Software Foundation, Inc.
  
     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
***************
*** 23,28 ****
--- 23,30 ----
  
  /* Assuming the stream STREAM is open for reading:
     Return the number of bytes waiting in the input buffer of STREAM.
+    This includes both the bytes that have been read from the underlying input
+    source and the bytes that have been pushed back through 'ungetc'.
  
     If this number is 0 and the stream is not currently writing,
     fflush (STREAM) is known to be a no-op.
*** lib/freadahead.c.orig       2008-03-10 01:57:39.000000000 +0100
--- lib/freadahead.c    2008-03-10 01:44:47.000000000 +0100
***************
*** 1,5 ****
  /* Retrieve information about a FILE stream.
!    Copyright (C) 2007 Free Software Foundation, Inc.
  
     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
--- 1,5 ----
  /* Retrieve information about a FILE stream.
!    Copyright (C) 2007-2008 Free Software Foundation, Inc.
  
     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
***************
*** 25,35 ****
  #if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
    if (fp->_IO_write_ptr > fp->_IO_write_base)
      return 0;
!   return fp->_IO_read_end - fp->_IO_read_ptr;
  #elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
    if ((fp->_flags & __SWR) != 0 || fp->_r < 0)
      return 0;
!   return fp->_r;
  #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, 
mingw */
  # if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */
  #  define fp_ ((struct { unsigned char *_ptr; \
--- 25,48 ----
  #if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
    if (fp->_IO_write_ptr > fp->_IO_write_base)
      return 0;
!   return (fp->_IO_read_end - fp->_IO_read_ptr)
!        + (fp->_flags & _IO_IN_BACKUP ? fp->_IO_save_end - fp->_IO_save_base :
!           0);
  #elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
+ # if defined __NetBSD__ || defined __OpenBSD__
+   struct __sfileext
+     {
+       struct  __sbuf _ub; /* ungetc buffer */
+       /* More fields, not relevant here.  */
+     };
+ # define HASUB(fp) (((struct __sfileext *) (fp)->_ext._base)->_ub._base != 
NULL)
+ # else
+ # define HASUB(fp) ((fp)->_ub._base != NULL)
+ # endif
    if ((fp->_flags & __SWR) != 0 || fp->_r < 0)
      return 0;
!   return fp->_r
!        + (HASUB (fp) ? fp->_ur : 0);
  #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, 
mingw */
  # if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */
  #  define fp_ ((struct { unsigned char *_ptr; \
***************
*** 51,66 ****
  # ifdef __STDIO_BUFFERS
    if (fp->__modeflags & __FLAG_WRITING)
      return 0;
!   return fp->__bufread - fp->__bufpos;
  # else
    return 0;
  # endif
  #elif defined __QNX__               /* QNX */
    if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
      return 0;
!   /* fp->_Buf <= fp->_Next <= fp->_Rend */
!   return fp->_Rend - fp->_Next;
  #else
!  #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."
  #endif
  }
--- 64,84 ----
  # ifdef __STDIO_BUFFERS
    if (fp->__modeflags & __FLAG_WRITING)
      return 0;
!   return (fp->__bufread - fp->__bufpos)
!        + (fp->__modeflags & __FLAG_UNGOT ? 1 : 0);
  # else
    return 0;
  # endif
  #elif defined __QNX__               /* QNX */
    if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
      return 0;
!   /* fp->_Buf <= fp->_Next <= fp->_Rend,
!      and fp->_Rend may be overridden by fp->_Rsave. */
!   return ((fp->_Rsave ? fp->_Rsave : fp->_Rend) - fp->_Next)
!        + (fp->_Mode & 0x4000 /* _MBYTE */
!           ? (fp->_Back + sizeof (fp->_Back)) - fp->_Rback
!           : 0);
  #else
!  #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."
  #endif
  }
*** tests/test-freadahead.c.orig        2008-03-10 01:57:39.000000000 +0100
--- tests/test-freadahead.c     2008-03-10 00:32:47.000000000 +0100
***************
*** 1,5 ****
  /* Test of freadahead() function.
!    Copyright (C) 2007 Free Software Foundation, Inc.
  
     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
--- 1,5 ----
  /* Test of freadahead() function.
!    Copyright (C) 2007-2008 Free Software Foundation, Inc.
  
     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
***************
*** 54,61 ****
           __STDIO_BUFFERS.  */
        ASSERT (freadahead (stdin) == 0);
        else
!       /* Normal buffered stdio.  */
!       ASSERT (freadahead (stdin) != 0);
      }
  
    return 0;
--- 54,82 ----
           __STDIO_BUFFERS.  */
        ASSERT (freadahead (stdin) == 0);
        else
!       {
!         /* Normal buffered stdio.  */
!         size_t buffered;
!         int c, c2;
! 
!         ASSERT (freadahead (stdin) != 0);
!         buffered = freadahead (stdin);
! 
!         c = fgetc (stdin);
!         ASSERT (freadahead (stdin) == buffered - 1);
!         ungetc (c, stdin);
!         ASSERT (freadahead (stdin) == buffered);
!         c2 = fgetc (stdin);
!         ASSERT (c2 == c);
!         ASSERT (freadahead (stdin) == buffered - 1);
! 
!         c = '@';
!         ungetc (c, stdin);
!         ASSERT (freadahead (stdin) == buffered);
!         c2 = fgetc (stdin);
!         ASSERT (c2 == c);
!         ASSERT (freadahead (stdin) == buffered - 1);
!       }
      }
  
    return 0;
*** NEWS.orig   2008-03-10 01:57:39.000000000 +0100
--- NEWS        2008-03-10 01:57:29.000000000 +0100
***************
*** 6,11 ****
--- 6,14 ----
  
  Date        Modules         Changes
  
+ 2008-03-06  freadahead      The return value's computation has changed. It
+                             now increases by 1 after ungetc.
+ 
  2008-01-26  isnan-nolibm    The module name is changed from isnan-nolibm to
                              isnand-nolibm. The include file is changed from
                              "isnan.h" to "isnand.h". The function that it