1 files changed, 150 insertions, 0 deletions

diff --git a/gl/fpurge.c b/gl/fpurge.c
new file mode 100644
index 0000000..0dcb2b7
--- /dev/null
+++ b/gl/fpurge.c
@@ -0,0 +1,150 @@
+/* Flushing buffers of a FILE stream.
+   Copyright (C) 2007-2023 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdio.h>
+
+#if HAVE___FPURGE                   /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
+# if HAVE_STDIO_EXT_H
+#  include <stdio_ext.h>
+# endif
+#endif
+#include <stdlib.h>
+
+#include "stdio-impl.h"
+
+int
+fpurge (FILE *fp)
+{
+#if HAVE___FPURGE                   /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
+
+  __fpurge (fp);
+  /* The __fpurge function does not have a return value.  */
+  return 0;
+
+#elif HAVE_FPURGE                   /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin >= 1.7 */
+
+  /* Call the system's fpurge function.  */
+# undef fpurge
+# if !HAVE_DECL_FPURGE
+  extern int fpurge (FILE *);
+# endif
+  int result = fpurge (fp);
+# if defined __sferror || defined __DragonFly__ || defined __ANDROID__
+  /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
+  if (result == 0)
+    /* Correct the invariants that fpurge broke.
+       <stdio.h> on BSD systems says:
+         "The following always hold: if _flags & __SRD, _w is 0."
+       If this invariant is not fulfilled and the stream is read-write but
+       currently reading, subsequent putc or fputc calls will write directly
+       into the buffer, although they shouldn't be allowed to.  */
+    if ((fp_->_flags & __SRD) != 0)
+      fp_->_w = 0;
+# endif
+  return result;
+
+#else
+
+  /* Most systems provide FILE as a struct and the necessary bitmask in
+     <stdio.h>, because they need it for implementing getc() and putc() as
+     fast macros.  */
+# if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
+  /* GNU libc, BeOS, Haiku, Linux libc5 */
+  fp->_IO_read_end = fp->_IO_read_ptr;
+  fp->_IO_write_ptr = fp->_IO_write_base;
+  /* Avoid memory leak when there is an active ungetc buffer.  */
+  if (fp->_IO_save_base != NULL)
+    {
+      free (fp->_IO_save_base);
+      fp->_IO_save_base = NULL;
+    }
+  return 0;
+# elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
+  /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
+  fp_->_p = fp_->_bf._base;
+  fp_->_r = 0;
+  fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
+             ? fp_->_bf._size
+             : 0);
+  /* Avoid memory leak when there is an active ungetc buffer.  */
+  if (fp_ub._base != NULL)
+    {
+      if (fp_ub._base != fp_->_ubuf)
+        free (fp_ub._base);
+      fp_ub._base = NULL;
+    }
+  return 0;
+# elif defined __EMX__              /* emx+gcc */
+  fp->_ptr = fp->_buffer;
+  fp->_rcount = 0;
+  fp->_wcount = 0;
+  fp->_ungetc_count = 0;
+  return 0;
+# elif defined __minix              /* Minix */
+  fp->_ptr = fp->_buf;
+  if (fp->_ptr != NULL)
+    fp->_count = 0;
+  return 0;
+# elif defined _IOERR               /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
+  fp_->_ptr = fp_->_base;
+  if (fp_->_ptr != NULL)
+    fp_->_cnt = 0;
+  return 0;
+# elif defined __UCLIBC__           /* uClibc */
+#  ifdef __STDIO_BUFFERS
+  if (fp->__modeflags & __FLAG_WRITING)
+    fp->__bufpos = fp->__bufstart;
+  else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
+    fp->__bufpos = fp->__bufread;
+#  endif
+  return 0;
+# elif defined __QNX__              /* QNX */
+  fp->_Rback = fp->_Back + sizeof (fp->_Back);
+  fp->_Rsave = NULL;
+  if (fp->_Mode & 0x2000 /* _MWRITE */)
+    /* fp->_Buf <= fp->_Next <= fp->_Wend */
+    fp->_Next = fp->_Buf;
+  else
+    /* fp->_Buf <= fp->_Next <= fp->_Rend */
+    fp->_Rend = fp->_Next;
+  return 0;
+# elif defined __MINT__             /* Atari FreeMiNT */
+  if (fp->__pushed_back)
+    {
+      fp->__bufp = fp->__pushback_bufp;
+      fp->__pushed_back = 0;
+    }
+  /* Preserve the current file position.  */
+  if (fp->__target != -1)
+    fp->__target += fp->__bufp - fp->__buffer;
+  fp->__bufp = fp->__buffer;
+  /* Nothing in the buffer, next getc is nontrivial.  */
+  fp->__get_limit = fp->__bufp;
+  /* Nothing in the buffer, next putc is nontrivial.  */
+  fp->__put_limit = fp->__buffer;
+  return 0;
+# elif defined EPLAN9               /* Plan9 */
+  fp->rp = fp->wp = fp->lp = fp->buf;
+  return 0;
+# else
+#  error "Please port gnulib fpurge.c to your platform! Look at the definitions of fflush, setvbuf and ungetc on your system, then report this to bug-gnulib."
+# endif
+
+#endif
+}