Add support for ferror(), feof(), and clearerr()

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5290 42af7a65-404d-4744-a932-0658087f49c3

nuttx/lib/stdio/Make.defs

@@ -34,27 +34,39 @@
 ############################################################################
 
 # Add the stdio C files to the build
+# This first group of C files do not depend on having file descriptors or
+# C streams.
 
 CSRCS += lib_fileno.c lib_printf.c lib_rawprintf.c lib_lowprintf.c \
-		  lib_sprintf.c lib_asprintf.c lib_snprintf.c lib_libsprintf.c \
-		  lib_vsprintf.c lib_avsprintf.c lib_vsnprintf.c lib_libvsprintf.c \
-		  lib_meminstream.c lib_memoutstream.c lib_lowinstream.c \
-		  lib_lowoutstream.c lib_zeroinstream.c lib_nullinstream.c \
-		  lib_nulloutstream.c lib_sscanf.c
+		 lib_sprintf.c lib_asprintf.c lib_snprintf.c lib_libsprintf.c \
+		 lib_vsprintf.c lib_avsprintf.c lib_vsnprintf.c lib_libvsprintf.c \
+		 lib_meminstream.c lib_memoutstream.c lib_lowinstream.c \
+		 lib_lowoutstream.c lib_zeroinstream.c lib_nullinstream.c \
+		 lib_nulloutstream.c lib_sscanf.c
+
+# The remaining sources files depend upon file descriptors
 
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
+
 CSRCS += lib_rawinstream.c lib_rawoutstream.c
+
+# And these depend upon both file descriptors and C streams
+
 ifneq ($(CONFIG_NFILE_STREAMS),0)
+
 CSRCS += lib_fopen.c lib_fclose.c lib_fread.c lib_libfread.c lib_fseek.c \
-		   lib_ftell.c lib_fsetpos.c lib_fgetpos.c lib_fgetc.c lib_fgets.c \
-		   lib_gets.c lib_fwrite.c lib_libfwrite.c lib_fflush.c \
-		   lib_libflushall.c lib_libfflush.c lib_rdflush.c lib_wrflush.c \
-		   lib_fputc.c lib_puts.c lib_fputs.c lib_ungetc.c lib_vprintf.c \
-		   lib_fprintf.c lib_vfprintf.c lib_stdinstream.c lib_stdoutstream.c \
-		   lib_perror.c
+		 lib_ftell.c lib_fsetpos.c lib_fgetpos.c lib_fgetc.c lib_fgets.c \
+		 lib_gets.c lib_fwrite.c lib_libfwrite.c lib_fflush.c \
+		 lib_libflushall.c lib_libfflush.c lib_rdflush.c lib_wrflush.c \
+		 lib_fputc.c lib_puts.c lib_fputs.c lib_ungetc.c lib_vprintf.c \
+		 lib_fprintf.c lib_vfprintf.c lib_stdinstream.c lib_stdoutstream.c \
+		 lib_perror.c lib_feof.c lib_ferror.c lib_clearerr.c
+
 endif
 endif
 
+# Other support that depends on specific, configured features.
+
 ifeq ($(CONFIG_SYSLOG),y)
 CSRCS += lib_syslogstream.c
 endif

nuttx/lib/stdio/lib_clearerr.c

@@ -0,0 +1,69 @@
+/****************************************************************************
+ * lib/stdio/lib_clearerr.c
+ *
+ *   Copyright (C) 2012 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#if CONFIG_NFILE_STREAMS > 0
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: Functions
+ *
+ * Description:
+ *   Clear any end-of-file or error conditions.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void clearerr(FILE *stream)
+{
+  stream->fs_flags = 0;
+}
+#endif /* CONFIG_NFILE_STREAMS */
+

nuttx/lib/stdio/lib_feof.c

@@ -0,0 +1,77 @@
+/****************************************************************************
+ * lib/stdio/lib_feof.c
+ *
+ *   Copyright (C) 2012 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#if CONFIG_NFILE_STREAMS > 0
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: feof
+ *
+ * Description:
+ *   The feof() function shall test if the currently file pointer for the
+ *   stream is at the end of file.
+ *
+ * Returned Value:
+ *  This function will return non-zero if the the file pointer is positioned
+ *  at the end of file.
+ *
+ ****************************************************************************/
+
+int feof(FILE *stream)
+{
+  /* If the end-of-file condition is encountered by any of the C-buffered
+   * I/O functions that perform read operations, they should set the
+   * __FS_FLAG_EOF in the fs_flags field of struct file_struct.
+   */
+
+  return (stream->fs_flags & __FS_FLAG_EOF) != 0;
+}
+
+#endif /* CONFIG_NFILE_STREAMS */
+

nuttx/lib/stdio/lib_ferror.c

@@ -0,0 +1,90 @@
+/****************************************************************************
+ * lib/stdio/lib_ferror.c
+ *
+ *   Copyright (C) 2012 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#if CONFIG_NFILE_STREAMS > 0
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ferror
+ *
+ * Description:
+ *   This function will test if the last operation resulted in an eror.  This
+ *   is used to disambiguate EOF and error conditions.
+ *
+ * Return Value:
+ *   A non-zero value is returned to indicate the error condition.
+ *
+ ****************************************************************************/
+
+int ferror(FILE *stream)
+{
+#if 0
+  /* If an error is encountered by any of the C-buffered I/O functions, they
+   * should set the __FS_FLAG_ERROR in the fs_flags field of struct
+   * file_struct.
+   */
+
+  return (stream->fs_flags & __FS_FLAG_ERROR) != 0;
+#else
+  /* However, nothing currenlty sets the __FS_FLAG_ERROR flag (that is a job
+   * for another day).  The __FS_FLAG_EOF is set by operations that perform
+   * read operations.  Since ferror()  is probably only called to disambiguate
+   * the meaning of other functions that return EOF, to indicate either EOF or
+   * an error, just testing for not EOF is probably sufficient for now.
+   *
+   * This approach would not work if ferror() is called in other contexts. In
+   * those cases, ferror() will always report an error.
+   */
+
+  return (stream->fs_flags & __FS_FLAG_EOF) == 0;
+#endif
+}
+
+#endif /* CONFIG_NFILE_STREAMS */
+

nuttx/lib/stdio/lib_libfread.c

@@ -187,7 +187,10 @@ ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream)
                     }
                   else if (bytes_read == 0)
                     {
-                      /* We are at the end of the file */
+                      /* We are at the end of the file.  But we may already
+                       * have buffered data.  In that case, we will report
+                       * the EOF indication later.
+                       */
 
                       goto shortread;
                     }
@@ -232,7 +235,10 @@ ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream)
                     }
                   else if (bytes_read == 0)
                     {
-                      /* We are at the end of the file */
+                      /* We are at the end of the file.  But we may already
+                       * have buffered data.  In that case, we will report
+                       * the EOF indication later.
+                       */
 
                       goto shortread;
                     }
@@ -261,6 +267,11 @@ ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream)
             }
           else if (bytes_read == 0)
             {
+              /* We are at the end of the file.  But we may already
+               * have buffered data.  In that case, we will report
+               * the EOF indication later.
+               */
+
               break;
             }
           else
@@ -270,12 +281,26 @@ ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream)
             }
         }
 #endif
-    /* Here after a successful (but perhaps short) read */
+      /* Here after a successful (but perhaps short) read */
 
 #if CONFIG_STDIO_BUFFER_SIZE > 0
     shortread:
 #endif
       bytes_read = dest - (unsigned char*)ptr;
+
+      /* Set or clear the EOF indicator.  If we get here because of a
+       * short read and the total number of* bytes read is zero, then
+       * we must be at the end-of-file.
+       */
+
+      if (bytes_read > 0)
+        {
+          stream->fs_flags &= ~__FS_FLAG_EOF;
+        }
+      else
+        {
+          stream->fs_flags |= __FS_FLAG_EOF;
+        }
     }
 
   lib_give_semaphore(stream);