Implemented __freading(), __fpurge(), and fpurge().

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28397 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/posix/stdio.h

@@ -96,6 +96,7 @@ extern void		perror(const char *errorPrefix);
 /* file I/O */
 extern int		fflush(FILE *stream);
 extern int		fflush_unlocked(FILE *stream);
+extern int		fpurge(FILE *stream);
 
 extern int		fgetpos(FILE *stream, fpos_t *position);
 extern int		fsetpos(FILE *stream, const fpos_t *position);

headers/posix/stdio_ext.h

@@ -17,12 +17,12 @@ extern "C" {
 
 /* The following stdio extensions are not implemented yet */
 /* extern size_t	__fufsize(FILE* stream); */
-/* extern int		__freading(FILE* stream); */
+extern int		__freading(FILE* stream);
 /* extern int		__fwriting(FILE* stream); */
 /* extern int		__freadable(FILE* stream); */
 /* extern int		__fwritable(FILE* stream); */
 /* extern int		__flbf(FILE* stream); */
-/* extern void		__fpurge(FILE* stream); */
+extern void		__fpurge(FILE* stream);
 /* extern size_t	__fpending(FILE* stream); */
 
 extern void		_flushlbf(void);

src/system/libroot/posix/stdio/Jamfile

@@ -3,7 +3,9 @@ SubDir HAIKU_TOP src system libroot posix stdio ;
 UsePrivateSystemHeaders ;
 
 MergeObject posix_stdio.o :
+	__freading.cpp
 	_fseek.c
+	fpurge.cpp
 	remove.c
 	rename.c
 # The other files are superseded by the glibc libio/stdio stuff

src/system/libroot/posix/stdio/__freading.cpp

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2008, Ingo Weinhold, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+
+#include <libio.h>
+#include <stdio_ext.h>
+
+
+int
+__freading(FILE* stream)
+{
+	// Return true, if writing is not allowed or the last operation was a read.
+	return (stream->_flags & _IO_NO_WRITES) != 0
+		|| ((stream->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
+			&& stream->_IO_read_base != NULL);
+}

src/system/libroot/posix/stdio/fpurge.cpp

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2008, Ingo Weinhold, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+
+#include <libio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+
+
+int
+fpurge(FILE* stream)
+{
+	// purge read and write buffers
+	stream->_IO_read_end = stream->_IO_read_ptr;
+	stream->_IO_write_ptr = stream->_IO_write_base;
+
+	// free ungetc buffer
+	if (stream->_IO_save_base != NULL) {
+		free(stream->_IO_save_base);
+		stream->_IO_save_base = NULL;
+	}
+
+	return 0;
+}
+
+
+void
+__fpurge(FILE* stream)
+{
+	fpurge(stream);
+}