import newlib-2000-02-17 snapshot

1 files changed, 126 insertions, 0 deletions

diff --git a/newlib/libc/stdio/ftell.c b/newlib/libc/stdio/ftell.c
new file mode 100644
index 000000000..6a8061816
--- /dev/null
+++ b/newlib/libc/stdio/ftell.c
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/*
+FUNCTION
+<<ftell>>---return position in a stream or file
+
+INDEX
+	ftell
+
+ANSI_SYNOPSIS
+	#include <stdio.h>
+	long ftell(FILE *<[fp]>);
+
+TRAD_SYNOPSIS
+	#include <stdio.h>
+	long ftell(<[fp]>)
+	FILE *<[fp]>;
+
+DESCRIPTION
+Objects of type <<FILE>> can have a ``position'' that records how much
+of the file your program has already read.  Many of the <<stdio>> functions
+depend on this position, and many change it as a side effect.
+
+The result of <<ftell>> is the current position for a file
+identified by <[fp]>.  If you record this result, you can later
+use it with <<fseek>> to return the file to this
+position.
+
+In the current implementation, <<ftell>> simply uses a character
+count to represent the file position; this is the same number that
+would be recorded by <<fgetpos>>.
+
+RETURNS
+<<ftell>> returns the file position, if possible.  If it cannot do
+this, it returns <<-1L>>.  Failure occurs on streams that do not support
+positioning; the global <<errno>> indicates this condition with the
+value <<ESPIPE>>.
+
+PORTABILITY
+<<ftell>> is required by the ANSI C standard, but the meaning of its
+result (when successful) is not specified beyond requiring that it be
+acceptable as an argument to <<fseek>>.  In particular, other
+conforming C implementations may return a different result from
+<<ftell>> than what <<fgetpos>> records.
+
+No supporting OS subroutines are required.
+*/
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "%W% (Berkeley) %G%";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * ftell: return current offset.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+
+#include "local.h"
+
+long
+_DEFUN (ftell, (fp),
+	register FILE * fp)
+{
+  fpos_t pos;
+
+  /* Ensure stdio is set up.  */
+
+  CHECK_INIT (fp);
+
+  if (fp->_seek == NULL)
+    {
+      fp->_data->_errno = ESPIPE;
+      return -1L;
+    }
+
+  /* Find offset of underlying I/O object, then
+     adjust for buffered bytes.  */
+  fflush(fp);           /* may adjust seek offset on append stream */
+  if (fp->_flags & __SOFF)
+    pos = fp->_offset;
+  else
+    {
+      pos = (*fp->_seek) (fp->_cookie, (fpos_t) 0, SEEK_CUR);
+      if (pos == -1L)
+	return pos;
+    }
+  if (fp->_flags & __SRD)
+    {
+      /*
+       * Reading.  Any unread characters (including
+       * those from ungetc) cause the position to be
+       * smaller than that in the underlying object.
+       */
+      pos -= fp->_r;
+      if (HASUB (fp))
+	pos -= fp->_ur;
+    }
+  else if (fp->_flags & __SWR && fp->_p != NULL)
+    {
+      /*
+       * Writing.  Any buffered characters cause the
+       * position to be greater than that in the
+       * underlying object.
+       */
+      pos += fp->_p - fp->_bf._base;
+    }
+
+  return pos;
+}