re PR fortran/60956 (error reading (and writing) large text files in gfortran)

2015-02-07  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR libgfortran/60956
	* io/fbuf.c (fbuf_flush_list): New function that only flushes
	if current fbuf position exceeds a limit.
	* io/fbuf.h: Declare the new function.
	* io/io.h (enum unit_mode): Add two new modes.
	* io/list_read.c (list_formatted_read_scalar): Call new function.
	* io/write.c: Include fbuf.h. (list_formatted_write_scalar):
	Call new function.

From-SVN: r220505

1 files changed, 36 insertions, 0 deletions

diff --git a/libgfortran/io/fbuf.c b/libgfortran/io/fbuf.c
index 9a3a486..b3750d2 100644
--- a/libgfortran/io/fbuf.c
+++ b/libgfortran/io/fbuf.c
@@ -171,6 +171,42 @@ fbuf_flush (gfc_unit * u, unit_mode mode)
 }
 
 
+/* The mode argument is LIST_WRITING for write mode and LIST_READING for
+   read.  This should only be used for list directed  I/O.
+   Return value is 0 for success, -1 on failure.  */
+
+int
+fbuf_flush_list (gfc_unit * u, unit_mode mode)
+{
+  int nwritten;
+
+  if (!u->fbuf)
+    return 0;
+
+  if (u->fbuf->pos < 524288) /* Upper limit for list writing.  */
+    return 0;
+
+  fbuf_debug (u, "fbuf_flush_list with mode %d: ", mode);
+
+  if (mode == LIST_WRITING)
+    {
+      nwritten = swrite (u->s, u->fbuf->buf, u->fbuf->pos);
+      if (nwritten < 0)
+	return -1;
+    }
+
+  /* Salvage remaining bytes for both reading and writing.  */ 
+  if (u->fbuf->act > u->fbuf->pos)
+    memmove (u->fbuf->buf, u->fbuf->buf + u->fbuf->pos, 
+             u->fbuf->act - u->fbuf->pos);
+
+  u->fbuf->act -= u->fbuf->pos;
+  u->fbuf->pos = 0;
+
+  return 0;
+}
+
+
 int
 fbuf_seek (gfc_unit * u, int off, int whence)
 {