1 files changed, 57 insertions, 0 deletions
diff --git a/src/util/win32/w32_buffer.c b/src/util/win32/w32_buffer.c
new file mode 100644
index 000000000..6fee8203c
--- /dev/null
+++ b/src/util/win32/w32_buffer.c
@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+
+#include "w32_buffer.h"
+
+#include "utf-conv.h"
+
+GIT_INLINE(int) handle_wc_error(void)
+{
+	if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+		errno = ENAMETOOLONG;
+	else
+		errno = EINVAL;
+
+	return -1;
+}
+
+int git_str_put_w(git_str *buf, const wchar_t *string_w, size_t len_w)
+{
+	int utf8_len, utf8_write_len;
+	size_t new_size;
+
+	if (!len_w) {
+		return 0;
+	} else if (len_w > INT_MAX) {
+		git_error_set_oom();
+		return -1;
+	}
+
+	GIT_ASSERT(string_w);
+
+	/* Measure the string necessary for conversion */
+	if ((utf8_len = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, string_w, (int)len_w, NULL, 0, NULL, NULL)) == 0)
+		return 0;
+
+	GIT_ASSERT(utf8_len > 0);
+
+	GIT_ERROR_CHECK_ALLOC_ADD(&new_size, buf->size, (size_t)utf8_len);
+	GIT_ERROR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
+
+	if (git_str_grow(buf, new_size) < 0)
+		return -1;
+
+	if ((utf8_write_len = WideCharToMultiByte(
+			CP_UTF8, WC_ERR_INVALID_CHARS, string_w, (int)len_w, &buf->ptr[buf->size], utf8_len, NULL, NULL)) == 0)
+		return handle_wc_error();
+
+	GIT_ASSERT(utf8_write_len == utf8_len);
+
+	buf->size += utf8_write_len;
+	buf->ptr[buf->size] = '\0';
+	return 0;
+}