[libc] Implement wcs to mbs family of functions

libc/config/linux/x86_64/entrypoints.txt

@@ -1263,6 +1263,9 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.wchar.mbtowc
     libc.src.wchar.wcrtomb
     libc.src.wchar.wctomb
+    libc.src.wchar.wcstombs
+    libc.src.wchar.wcsrtombs
+    libc.src.wchar.wcsnrtombs
   )
 endif()
 

libc/include/wchar.yaml

@@ -274,3 +274,31 @@ functions:
       - type: const wchar_t *__restrict
       - type: wchar_t **__restrict
       - type: int
+  - name: wcstombs
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: char *__restrict
+      - type: const wchar_t *__restrict
+      - type: size_t
+  - name: wcsrtombs
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: char *__restrict
+      - type: const wchar_t **__restrict
+      - type: size_t
+      - type: mbstate_t
+  - name: wcsnrtombs
+    standards:
+      - stdc
+    return_type: size_t
+    arguments:
+      - type: char *__restrict
+      - type: const wchar_t **__restrict
+      - type: size_t
+      - type: size_t
+      - type: mbstate_t
+

libc/src/__support/wchar/CMakeLists.txt

@@ -68,3 +68,20 @@ add_object_library(
   .character_converter
   .mbstate
 )
+
+add_header_library(
+  wcsnrtombs
+  HDRS
+    wcsnrtombs.h
+  DEPENDS
+    libc.hdr.errno_macros
+    libc.hdr.types.char8_t
+    libc.hdr.types.char32_t
+    libc.hdr.types.size_t
+    libc.hdr.types.wchar_t
+    libc.src.__support.error_or
+    libc.src.__support.common
+    .string_converter
+    .character_converter
+    .mbstate
+)

libc/src/__support/wchar/wcsnrtombs.h

@@ -0,0 +1,69 @@
+//===-- Implementation header for wcsnrtombs ------------------------------===//
+//
+// 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__SUPPORT_WCHAR_WCSNRTOMBS_H
+#define LLVM_LIBC_SRC__SUPPORT_WCHAR_WCSNRTOMBS_H
+
+#include "hdr/types/char32_t.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/macros/null_check.h"
+#include "src/__support/wchar/mbstate.h"
+#include "src/__support/wchar/string_converter.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+
+LIBC_INLINE static ErrorOr<size_t> wcsnrtombs(char *__restrict s,
+                                              const wchar_t **__restrict pwcs,
+                                              size_t nwc, size_t len,
+                                              mbstate *ps) {
+  LIBC_CRASH_ON_NULLPTR(pwcs);
+  LIBC_CRASH_ON_NULLPTR(ps);
+
+  CharacterConverter cr(ps);
+  if (!cr.isValidState())
+    return Error(EINVAL);
+
+  if (s == nullptr)
+    len = SIZE_MAX;
+
+  StringConverter<char32_t> str_conv(reinterpret_cast<const char32_t *>(*pwcs),
+                                     ps, len, nwc);
+  size_t dst_idx = 0;
+  ErrorOr<char8_t> converted = str_conv.popUTF8();
+  while (converted.has_value()) {
+    if (s != nullptr)
+      s[dst_idx] = converted.value();
+
+    if (converted.value() == '\0') {
+      if (s != nullptr)
+        *pwcs = nullptr;
+      return dst_idx;
+    }
+
+    dst_idx++;
+    converted = str_conv.popUTF8();
+  }
+
+  if (s != nullptr)
+    *pwcs += str_conv.getSourceIndex();
+
+  if (converted.error() == -1) // if we hit conversion limit
+    return dst_idx;
+
+  return Error(converted.error());
+}
+
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC__SUPPORT_WCHAR_WCSNRTOMBS_H

libc/src/wchar/CMakeLists.txt

@@ -159,6 +159,47 @@ add_entrypoint_object(
     libc.src.__support.wchar.mbstate
 )
 
+add_entrypoint_object(
+  wcstombs
+  SRCS
+    wcstombs.cpp
+  HDRS
+    wcstombs.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.wchar.wcsnrtombs
+    libc.src.__support.libc_errno
+)
+
+add_entrypoint_object(
+  wcsrtombs
+  SRCS
+    wcsrtombs.cpp
+  HDRS
+    wcsrtombs.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    libc.hdr.types.mbstate_t
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.wchar.wcsnrtombs
+    libc.src.__support.libc_errno
+)
+
+add_entrypoint_object(
+  wcsnrtombs
+  SRCS
+    wcsnrtombs.cpp
+  HDRS
+    wcsnrtombs.h
+  DEPENDS
+    libc.hdr.types.wchar_t
+    libc.hdr.types.mbstate_t
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.wchar.wcsnrtombs
+    libc.src.__support.libc_errno
+)
+
 add_entrypoint_object(
   wmemset
   SRCS

libc/src/wchar/wcsnrtombs.cpp

@@ -0,0 +1,40 @@
+//===-- Implementation of wcsnrtombs --------------------------------------===//
+//
+// 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/wcsnrtombs.h"
+
+#include "hdr/types/char32_t.h"
+#include "hdr/types/mbstate_t.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/mbstate.h"
+#include "src/__support/wchar/wcsnrtombs.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcsnrtombs,
+                   (char *__restrict s, const wchar_t **__restrict pwcs,
+                    size_t nwc, size_t len, mbstate_t *ps)) {
+  LIBC_CRASH_ON_NULLPTR(pwcs);
+  static internal::mbstate internal_mbstate;
+  auto result = internal::wcsnrtombs(
+      s, pwcs, nwc, len,
+      ps == nullptr ? &internal_mbstate
+                    : reinterpret_cast<internal::mbstate *>(ps));
+  if (!result.has_value()) {
+    libc_errno = result.error();
+    return -1;
+  }
+
+  return result.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wcsnrtombs.h

@@ -0,0 +1,24 @@
+//===-- Implementation header for wcsnrtombs ------------------------------===//
+//
+// 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_WCHAR_WCSNRTOMBS_H
+#define LLVM_LIBC_SRC_WCHAR_WCSNRTOMBS_H
+
+#include "hdr/types/mbstate_t.h"
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+size_t wcsnrtombs(char *__restrict s, const wchar_t **__restrict pwcs,
+                  size_t nwc, size_t len, mbstate_t *ps);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSNRTOMBS_H

libc/src/wchar/wcsrtombs.cpp

@@ -0,0 +1,40 @@
+//===-- Implementation of wcsrtombs ---------------------------------------===//
+//
+// 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/wcsrtombs.h"
+
+#include "hdr/types/char32_t.h"
+#include "hdr/types/mbstate_t.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/mbstate.h"
+#include "src/__support/wchar/wcsnrtombs.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcsrtombs,
+                   (char *__restrict s, const wchar_t **__restrict pwcs,
+                    size_t n, mbstate_t *ps)) {
+  LIBC_CRASH_ON_NULLPTR(pwcs);
+  static internal::mbstate internal_mbstate;
+  auto result = internal::wcsnrtombs(
+      s, pwcs, SIZE_MAX, n,
+      ps == nullptr ? &internal_mbstate
+                    : reinterpret_cast<internal::mbstate *>(ps));
+  if (!result.has_value()) {
+    libc_errno = result.error();
+    return -1;
+  }
+
+  return result.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wcsrtombs.h

@@ -0,0 +1,24 @@
+//===-- Implementation header for wcsrtombs -------------------------------===//
+//
+// 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_WCHAR_WCSRTOMBS_H
+#define LLVM_LIBC_SRC_WCHAR_WCSRTOMBS_H
+
+#include "hdr/types/mbstate_t.h"
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+size_t wcsrtombs(char *__restrict s, const wchar_t **__restrict pwcs, size_t n,
+                 mbstate_t *ps);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSRTOMBS_H

libc/src/wchar/wcstombs.cpp

@@ -0,0 +1,38 @@
+//===-- Implementation of wcstombs ----------------------------------------===//
+//
+// 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/wcstombs.h"
+
+#include "hdr/types/char32_t.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/mbstate.h"
+#include "src/__support/wchar/wcsnrtombs.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcstombs,
+                   (char *__restrict s, const wchar_t *__restrict wcs,
+                    size_t n)) {
+  LIBC_CRASH_ON_NULLPTR(wcs);
+  static internal::mbstate internal_mbstate;
+  const wchar_t *wcs_ptr_copy = wcs;
+  auto result =
+      internal::wcsnrtombs(s, &wcs_ptr_copy, SIZE_MAX, n, &internal_mbstate);
+  if (!result.has_value()) {
+    libc_errno = result.error();
+    return -1;
+  }
+
+  return result.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wcstombs.h

@@ -0,0 +1,22 @@
+//===-- Implementation header for wcstombs --------------------------------===//
+//
+// 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_WCHAR_WCSTOMBS_H
+#define LLVM_LIBC_SRC_WCHAR_WCSTOMBS_H
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+size_t wcstombs(char *__restrict s, const wchar_t *__restrict pwcs, size_t n);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSTOMBS_H

libc/test/src/__support/wchar/CMakeLists.txt

@@ -34,3 +34,20 @@ add_libc_test(
     libc.hdr.errno_macros
     libc.hdr.types.char32_t
 )
+
+add_libc_test(
+  wcsnrtombs_test
+  SUITE
+    libc-support-tests
+  SRCS
+    wcsnrtombs_test.cpp
+  DEPENDS
+    libc.src.__support.wchar.string_converter
+    libc.src.__support.wchar.character_converter
+    libc.src.__support.wchar.mbstate
+    libc.src.__support.error_or
+    libc.src.__support.wchar.wcsnrtombs
+    libc.hdr.errno_macros
+    libc.hdr.types.char32_t
+    libc.hdr.types.char8_t
+)