1 files changed, 39 insertions, 0 deletions
diff --git a/libc/src/wchar/mbsrtowcs.cpp b/libc/src/wchar/mbsrtowcs.cpp
new file mode 100644
index 0000000..82ca25a
--- /dev/null
+++ b/libc/src/wchar/mbsrtowcs.cpp
@@ -0,0 +1,39 @@
+//===-- Implementation of mbsrtowcs ---------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/wchar/mbsrtowcs.h"
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/wchar/mbsnrtowcs.h"
+#include "src/__support/wchar/mbstate.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, mbsrtowcs,
+                   (wchar_t *__restrict dst, const char **__restrict src,
+                    size_t len, mbstate_t *__restrict ps)) {
+  static internal::mbstate internal_mbstate;
+  // If destination is null, ignore len
+  len = dst == nullptr ? SIZE_MAX : len;
+  auto ret = internal::mbsnrtowcs(
+      dst, src, SIZE_MAX, len,
+      ps == nullptr ? &internal_mbstate
+                    : reinterpret_cast<internal::mbstate *>(ps));
+  if (!ret.has_value()) {
+    // Encoding failure
+    libc_errno = ret.error();
+    return -1;
+  }
+  return ret.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL