1 files changed, 75 insertions, 0 deletions
diff --git a/libc/stdio/_trans2r.c b/libc/stdio/_trans2r.c
new file mode 100644
index 000000000..d33d9eba8
--- /dev/null
+++ b/libc/stdio/_trans2r.c
@@ -0,0 +1,75 @@
+/* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
+ *
+ * GNU Library General Public License (LGPL) version 2 or later.
+ *
+ * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
+ */
+
+#include "_stdio.h"
+
+/* Function to handle transition to reading.
+ *   Initialize or verify the stream's orientation (even if writeonly).
+ *   Check that the stream is readable.
+ *   If currently reading, check that we can transition to writing.
+ *      C99 requires that we not be reading, but attempting to
+ *      auto-transition by commiting the write buffer is a configurable
+ *      option.
+ *   Returns 0 on success and EOF otherwise.
+ *
+ * Notes:
+ *   There are two function signatures, depending on wchar support,
+ *   since with no wchar support the orientation is narrow by default.
+ */
+
+#ifdef __UCLIBC_HAS_WCHAR__
+int __stdio_trans2r_o(FILE * __restrict stream, int oflag)
+#else
+int __stdio_trans2r(FILE * __restrict stream)
+#endif
+{
+	__STDIO_STREAM_VALIDATE(stream);
+	assert(!__STDIO_STREAM_IS_READING(stream));
+
+#ifdef __UCLIBC_HAS_WCHAR__
+	if (!(stream->__modeflags & oflag)) {
+		if (stream->__modeflags & (__FLAG_NARROW|__FLAG_WIDE)) {
+			__UNDEFINED_OR_NONPORTABLE;
+			goto DO_EBADF;
+		}
+		stream->__modeflags |= oflag;
+	}
+#endif
+
+	if (stream->__modeflags & __FLAG_WRITEONLY) {
+	DO_EBADF:
+		__set_errno(EBADF);
+	ERROR:
+		__STDIO_STREAM_SET_ERROR(stream);
+		__STDIO_STREAM_VALIDATE(stream);
+		return EOF;
+	}
+
+	if (__STDIO_STREAM_IS_WRITING(stream)) {
+#ifdef __UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION__
+		if (__STDIO_COMMIT_WRITE_BUFFER(stream)) { /* commit failed! */
+			goto ERROR;
+		}
+		assert(!__STDIO_STREAM_BUFFER_WUSED(stream));
+
+		__STDIO_STREAM_DISABLE_PUTC(stream);
+		__STDIO_STREAM_CLEAR_WRITING(stream);
+#else
+		/* C99: Output shall not be directly followed by input without an
+		   intervening call to the fflush function or to a file positioning
+		   function (fseek, fsetpos, or rewind). */
+		__UNDEFINED_OR_NONPORTABLE;
+		goto DO_EBADF;
+#endif
+	}
+
+	__STDIO_STREAM_SET_READING(stream);
+	/* getc macro is enabled when data is read into buffer. */
+
+	__STDIO_STREAM_VALIDATE(stream);
+	return 0;
+}