1 files changed, 121 insertions, 0 deletions
diff --git a/nuttx/lib/stdio/lib_ungetc.c b/nuttx/lib/stdio/lib_ungetc.c
new file mode 100644
index 000000000..c10d4fba1
--- /dev/null
+++ b/nuttx/lib/stdio/lib_ungetc.c
@@ -0,0 +1,121 @@
+/****************************************************************************
+ * lib/stdio/lib_ungetc.c
+ *
+ *   Copyright (C) 2007, 2008, 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Compilation Switches
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <nuttx/fs/fs.h>
+#include "lib_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Function Prototypes
+ ****************************************************************************/
+
+/**************************************************************************
+ * Global Constant Data
+ **************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/**************************************************************************
+ * Private Constant Data
+ **************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ **************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ **************************************************************************/
+
+/****************************************************************************
+ * Name: ungetc
+ **************************************************************************/
+
+int ungetc(int c, FAR FILE *stream)
+{
+#if CONFIG_NUNGET_CHARS > 0
+  int nungotten;
+#endif
+
+  /* Stream must be open for read access */
+
+  if ((stream && stream->fs_filedes < 0) ||
+      ((stream->fs_oflags & O_RDOK) == 0))
+    {
+      set_errno(EBADF);
+      return EOF;
+    }
+
+#if CONFIG_NUNGET_CHARS > 0
+  nungotten = stream->fs_nungotten;
+  if (stream->fs_nungotten < CONFIG_NUNGET_CHARS)
+    {
+      stream->fs_ungotten[nungotten] = c;
+      stream->fs_nungotten = nungotten + 1;
+      return c;
+    }
+  else
+#endif
+    {
+      set_errno(ENOMEM);
+      return EOF;
+    }
+}
+