1 files changed, 125 insertions, 0 deletions
diff --git a/lib/freadptr.c b/lib/freadptr.c
new file mode 100644
index 0000000..49f203a
--- /dev/null
+++ b/lib/freadptr.c
@@ -0,0 +1,125 @@
+/* Retrieve information about 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 "freadptr.h"
+
+#include <stdlib.h>
+
+#include "stdio-impl.h"
+
+/* This file is not used on systems that have the __freadptr function,
+   namely musl libc.  */
+
+const char *
+freadptr (FILE *fp, size_t *sizep)
+{
+  size_t size;
+
+  /* Keep this code in sync with freadahead!  */
+#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
+  /* GNU libc, BeOS, Haiku, Linux libc5 */
+  if (fp->_IO_write_ptr > fp->_IO_write_base)
+    return NULL;
+  size = fp->_IO_read_end - fp->_IO_read_ptr;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp->_IO_read_ptr;
+#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
+  /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
+  if ((fp_->_flags & __SWR) != 0 || fp_->_r < 0)
+    return NULL;
+  size = fp_->_r;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp_->_p;
+#elif defined __EMX__               /* emx+gcc */
+  if ((fp->_flags & _IOWRT) != 0)
+    return NULL;
+  /* Note: fp->_ungetc_count > 0 implies fp->_rcount <= 0,
+           fp->_ungetc_count = 0 implies fp->_rcount >= 0.  */
+  if (fp->_rcount <= 0)
+    return NULL;
+  if (!(fp->_ungetc_count == 0))
+    abort ();
+  *sizep = fp->_rcount;
+  return fp->_ptr;
+#elif defined __minix               /* Minix */
+  if ((fp_->_flags & _IOWRITING) != 0)
+    return NULL;
+  size = fp_->_count;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp_->_ptr;
+#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
+  if ((fp_->_flag & _IOWRT) != 0)
+    return NULL;
+  size = fp_->_cnt;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp_->_ptr;
+#elif defined __UCLIBC__            /* uClibc */
+# ifdef __STDIO_BUFFERS
+  if (fp->__modeflags & __FLAG_WRITING)
+    return NULL;
+  if (fp->__modeflags & __FLAG_UNGOT)
+    return NULL;
+  size = fp->__bufread - fp->__bufpos;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp->__bufpos;
+# else
+  return NULL;
+# endif
+#elif defined __QNX__               /* QNX */
+  if ((fp->_Mode & 0x2000 /* _MWRITE */) != 0)
+    return NULL;
+  /* fp->_Buf <= fp->_Next <= fp->_Rend */
+  size = fp->_Rend - fp->_Next;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return (const char *) fp->_Next;
+#elif defined __MINT__              /* Atari FreeMiNT */
+  if (!fp->__mode.__read)
+    return NULL;
+  size = fp->__get_limit - fp->__bufp;
+  if (size == 0)
+    return NULL;
+  *sizep = size;
+  return fp->__bufp;
+#elif defined EPLAN9                /* Plan9 */
+  if (fp->state == 4 /* WR */)
+    return NULL;
+  if (fp->rp >= fp->wp)
+    return NULL;
+  *sizep = fp->wp - fp->rp;
+  return fp->rp;
+#elif defined SLOW_BUT_NO_HACKS     /* users can define this */
+  /* This implementation is correct on any ANSI C platform.  It is just
+     awfully slow.  */
+  return NULL;
+#else
+ #error "Please port gnulib freadptr.c to your platform! Look at the definition of fflush, fread, getc, getc_unlocked on your system, then report this to bug-gnulib."
+#endif
+}