[libc] Add ctime_s

Resolves #110548 Definition: ```c++ int ctime_s(char *buffer, size_t buffer_size, const time_t *t_ptr); ```

Author: Rajveer100

libc/src/time/ctime_s.cpp

@@ -0,0 +1,39 @@
+//===-- Implementation of ctime_s function --------------------------------===//
+//
+// 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 "ctime_s.h"
+#include "src/__support/CPP/limits.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "time_utils.h"
+#include <cerrno>
+
+namespace LIBC_NAMESPACE_DECL {
+
+using LIBC_NAMESPACE::time_utils::TimeConstants;
+
+LLVM_LIBC_FUNCTION(int, ctime_s,
+ (char *buffer, size_t buffer_size, const time_t *t_ptr)) {
+ if (t_ptr == nullptr || buffer == nullptr ||
+ *time > cpp::numeric_limits<int32_t>::max()) {
+ return EINVAL;
+ }
+
+ if (buffer_size < TimeConstants::ASCTIME_MAX_BYTES) {
+ return ERANGE;
+ }
+
+ if (time_utils::asctime(time_utils::localtime(t_ptr), buffer, buffer_size) ==
+ nullptr) {
+ return EINVAL;
+ }
+
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/time/ctime_s.h

@@ -0,0 +1,21 @@
+//===-- Implementation header of ctime_s ------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_TIME_CTIME_S_H
+#define LLVM_LIBC_SRC_TIME_CTIME_S_H
+
+#include "hdr/types/time_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int ctime_s(char *buffer, size_t buffer_size, const time_t *t_ptr);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_TIME_CTIME_S_H