utf8: refactor utf8 functions

Move the utf8 functions into a proper namespace `git_utf8` instead of
being in the namespaceless `git__` function group.  Update them to
have out-params first and use `char *` instead of `uint8_t *` to match
our API treating strings as `char *` (even if they truly contain `uchar`s
inside).

1 files changed, 32 insertions, 0 deletions

diff --git a/src/utf8.h b/src/utf8.h
new file mode 100644
index 000000000..71c8f3bee
--- /dev/null
+++ b/src/utf8.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_utf8_h__
+#define INCLUDE_utf8_h__
+
+#include "common.h"
+
+/*
+ * Iterate through an UTF-8 string, yielding one codepoint at a time.
+ *
+ * @param out pointer where to store the current codepoint
+ * @param str current position in the string
+ * @param str_len size left in the string
+ * @return length in bytes of the read codepoint; -1 if the codepoint was invalid
+ */
+extern int git_utf8_iterate(uint32_t *out, const char *str, size_t str_len);
+
+/**
+ * Iterate through an UTF-8 string and stops after finding any invalid UTF-8
+ * codepoints.
+ *
+ * @param str string to scan
+ * @param str_len size of the string
+ * @return length in bytes of the string that contains valid data
+ */
+extern size_t git_utf8_valid_buf_length(const char *str, size_t str_len);
+
+#endif