[libc] mbrtowc implementation #144760
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[libc] mbrtowc implementation #144760
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added 2 commits
June 17, 2025 20:19
implemented the internal and public mbrtowc as well as tests for the public function.
|
@llvm/pr-subscribers-libc Author: None (sribee8) Changesimplemented the internal and public mbrtowc as well as tests for the public function. Full diff: https://github.com/llvm/llvm-project/pull/144760.diff 13 Files Affected:
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index aa2079faed409..10509a0c25835 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -365,6 +365,7 @@ set(TARGET_LIBC_ENTRYPOINTS
# wchar.h entrypoints
libc.src.wchar.btowc
+ libc.src.wchar.mbrtowc
libc.src.wchar.wcslen
libc.src.wchar.wctob
libc.src.wchar.wmemmove
diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index c88c357009072..e4b3cb0faa820 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -20,6 +20,14 @@ add_proxy_header_library(
libc.include.uchar
)
+add_proxy_header_library(
+ mbstate_t
+ HDRS
+ mbstate_t.h
+ DEPENDS
+ libc.include.llvm-libc-types.mbstate_t
+)
+
add_proxy_header_library(
div_t
HDRS
diff --git a/libc/hdr/types/mbstate_t.h b/libc/hdr/types/mbstate_t.h
new file mode 100644
index 0000000000000..15b2614341d7d
--- /dev/null
+++ b/libc/hdr/types/mbstate_t.h
@@ -0,0 +1,22 @@
+//===-- Definition of macros from mbstate_t.h -----------------------------===//
+//
+// 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_HDR_TYPES_MBSTATE_T_H
+#define LLVM_LIBC_HDR_TYPES_MBSTATE_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/mbstate_t.h"
+
+#else // Overlay mode
+
+#include "hdr/wchar_overlay.h"
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_MBSTATE_T_H
diff --git a/libc/include/llvm-libc-types/mbstate_t.h b/libc/include/llvm-libc-types/mbstate_t.h
index 540d50975a264..009fe57da50e2 100644
--- a/libc/include/llvm-libc-types/mbstate_t.h
+++ b/libc/include/llvm-libc-types/mbstate_t.h
@@ -9,8 +9,12 @@
#ifndef LLVM_LIBC_TYPES_MBSTATE_T_H
#define LLVM_LIBC_TYPES_MBSTATE_T_H
-// TODO: Complete this once we implement functions that operate on this type.
+#include "../llvm-libc-macros/stdint-macros.h"
+
typedef struct {
+ uint32_t __field1;
+ uint8_t __field2;
+ uint8_t __field3;
} mbstate_t;
#endif // LLVM_LIBC_TYPES_MBSTATE_T_H
diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index 84db73d8f01ea..06c621f59b462 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -29,6 +29,15 @@ functions:
return_type: wint_t
arguments:
- type: int
+ - name: mbrtowc
+ standards:
+ - stdc
+ return_type: size_t
+ arguments:
+ - type: wchar_t * __restrict
+ - type: const char * __restrict
+ - type: size_t
+ - type: mbstate_t * __restrict
- name: wmemset
standards:
- stdc
diff --git a/libc/src/__support/wchar/CMakeLists.txt b/libc/src/__support/wchar/CMakeLists.txt
index 6715e354e23e5..479c1dff2c6e0 100644
--- a/libc/src/__support/wchar/CMakeLists.txt
+++ b/libc/src/__support/wchar/CMakeLists.txt
@@ -19,3 +19,19 @@ add_object_library(
libc.src.__support.math_extras
.mbstate
)
+
+add_object_library(
+ mbrtowc
+ HDRS
+ mbrtowc.h
+ SRCS
+ mbrtowc.cpp
+ DEPENDS
+ libc.hdr.types.wchar_t
+ libc.hdr.types.size_t
+ libc.src.__support.common
+ libc.src.__support.error_or
+ libc.src.__support.macros.config
+ .character_converter
+ .mbstate
+)
diff --git a/libc/src/__support/wchar/mbrtowc.cpp b/libc/src/__support/wchar/mbrtowc.cpp
new file mode 100644
index 0000000000000..969448ee60e81
--- /dev/null
+++ b/libc/src/__support/wchar/mbrtowc.cpp
@@ -0,0 +1,50 @@
+//===-- Implementation for mbrtowc function ---------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/wchar/mbrtowc.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/error_or.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/wchar/character_converter.h"
+#include "src/__support/wchar/mbstate.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+
+ErrorOr<size_t> mbrtowc(wchar_t *__restrict pwc, const char *__restrict s,
+ size_t n, mbstate *__restrict ps) {
+ CharacterConverter char_conv(ps);
+ if (s == nullptr)
+ return 0;
+ size_t i = 0;
+ auto wc = char_conv.pop_utf32();
+ // Reading in bytes until we have a complete wc or error
+ for (; i < n && !wc.has_value(); ++i) {
+ int err = char_conv.push(static_cast<char8_t>(s[i]));
+ // Encoding error
+ if (err == -1)
+ return Error(-1);
+ wc = char_conv.pop_utf32();
+ }
+ if (wc.has_value()) {
+ *pwc = wc.value();
+ // null terminator -> return 0
+ if (wc.value() == L'\0')
+ return 0;
+ return i;
+ }
+ // Incomplete but potentially valid
+ return Error(-2);
+}
+
+} // namespace internal
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/__support/wchar/mbrtowc.h b/libc/src/__support/wchar/mbrtowc.h
new file mode 100644
index 0000000000000..37329ee61beac
--- /dev/null
+++ b/libc/src/__support/wchar/mbrtowc.h
@@ -0,0 +1,29 @@
+//===-- Implementation header for mbrtowc function --------------*- 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___SUPPORT_WCHAR_MBRTOWC
+#define LLVM_LIBC_SRC___SUPPORT_WCHAR_MBRTOWC
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/wchar/mbstate.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+
+ErrorOr<size_t> mbrtowc(wchar_t *__restrict pwc, const char *__restrict s,
+ size_t n, mbstate *__restrict ps);
+
+} // namespace internal
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_WCHAR_MBRTOWC
diff --git a/libc/src/wchar/CMakeLists.txt b/libc/src/wchar/CMakeLists.txt
index 491dd5b34340a..163c29847e6a2 100644
--- a/libc/src/wchar/CMakeLists.txt
+++ b/libc/src/wchar/CMakeLists.txt
@@ -34,6 +34,23 @@ add_entrypoint_object(
libc.src.__support.wctype_utils
)
+add_entrypoint_object(
+ mbrtowc
+ SRCS
+ mbrtowc.cpp
+ HDRS
+ mbrtowc.h
+ DEPENDS
+ libc.hdr.types.size_t
+ libc.hdr.types.mbstate_t
+ libc.hdr.types.wchar_t
+ libc.src.__support.common
+ libc.src.__support.macros.config
+ libc.src.__support.wchar.mbrtowc
+ libc.src.__support.libc_errno
+ libc.src.__support.wchar.mbstate
+)
+
add_entrypoint_object(
wmemset
SRCS
diff --git a/libc/src/wchar/mbrtowc.cpp b/libc/src/wchar/mbrtowc.cpp
new file mode 100644
index 0000000000000..c29c5ee161e32
--- /dev/null
+++ b/libc/src/wchar/mbrtowc.cpp
@@ -0,0 +1,40 @@
+//===-- Implementation of mbrtowc -----------------------------------------===//
+//
+// 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/mbrtowc.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/mbrtowc.h"
+#include "src/__support/wchar/mbstate.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, mbrtowc,
+ (wchar_t *__restrict pwc, const char *__restrict s, size_t n,
+ mbstate_t *__restrict ps)) {
+ static mbstate_t internal_mbstate{0, 0, 0};
+ auto ret = internal::mbrtowc(
+ pwc, s, n, (internal::mbstate *)(ps == nullptr ? &internal_mbstate : ps));
+ if (!ret.has_value()) {
+ // Encoding failure
+ if (ret.error() == -1) {
+ libc_errno = EILSEQ;
+ return -1;
+ }
+ // Could potentially read a valid wide character.
+ return -2;
+ }
+ return ret.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/mbrtowc.h b/libc/src/wchar/mbrtowc.h
new file mode 100644
index 0000000000000..e2e3d3ebd2853
--- /dev/null
+++ b/libc/src/wchar/mbrtowc.h
@@ -0,0 +1,24 @@
+//===-- Implementation header for mbrtowc ---------------------------------===//
+//
+// 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_MBRTOWC_H
+#define LLVM_LIBC_SRC_WCHAR_MBRTOWC_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 mbrtowc(wchar_t *__restrict pwc, const char *__restrict s, size_t n,
+ mbstate_t *__restrict ps);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_MBRTOWC_H
diff --git a/libc/test/src/wchar/CMakeLists.txt b/libc/test/src/wchar/CMakeLists.txt
index 4990b6953348b..d4cae1f6228bd 100644
--- a/libc/test/src/wchar/CMakeLists.txt
+++ b/libc/test/src/wchar/CMakeLists.txt
@@ -23,6 +23,20 @@ add_libc_test(
libc.src.wchar.btowc
)
+add_libc_test(
+ mbrtowc_test
+ SUITE
+ libc_wchar_unittests
+ SRCS
+ mbrtowc_test.cpp
+ DEPENDS
+ libc.src.__support.libc_errno
+ libc.src.string.memset
+ libc.src.wchar.mbrtowc
+ libc.hdr.types.mbstate_t
+ libc.hdr.types.wchar_t
+)
+
add_libc_test(
wctob_test
SUITE
diff --git a/libc/test/src/wchar/mbrtowc_test.cpp b/libc/test/src/wchar/mbrtowc_test.cpp
new file mode 100644
index 0000000000000..6e96e7ac31f49
--- /dev/null
+++ b/libc/test/src/wchar/mbrtowc_test.cpp
@@ -0,0 +1,170 @@
+//===-- Unittests for mbrtowc ---------------------------------------------===//
+//
+// 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 "hdr/types/mbstate_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/libc_errno.h"
+#include "src/string/memset.h"
+#include "src/wchar/mbrtowc.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcMBRToWC, OneByte) {
+ const char *ch = "A";
+ wchar_t dest[2];
+ // Testing if it works with nullptr mbstate_t
+ mbstate_t *mb = nullptr;
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<char>(*dest), 'A');
+ ASSERT_EQ(static_cast<int>(n), 1);
+
+ // Should fail since we have not read enough
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 0, mb);
+ ASSERT_EQ(static_cast<int>(n), -2);
+}
+
+TEST(LlvmLibcMBRToWC, TwoByte) {
+ const char ch[2] = {static_cast<char>(0xC2),
+ static_cast<char>(0x8E)}; // � car symbol
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 2, mb);
+ ASSERT_EQ(static_cast<int>(*dest), 142);
+ ASSERT_EQ(static_cast<int>(n), 2);
+
+ // Should fail since we have not read enough
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), -2);
+ // Should pass after reading one more byte
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), 1);
+ ASSERT_EQ(static_cast<int>(*dest), 142);
+}
+
+TEST(LlvmLibcMBRToWC, ThreeByte) {
+ const char ch[3] = {static_cast<char>(0xE2), static_cast<char>(0x88),
+ static_cast<char>(0x91)}; // ∑ sigma symbol
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 3, mb);
+ ASSERT_EQ(static_cast<int>(*dest), 8721);
+ ASSERT_EQ(static_cast<int>(n), 3);
+
+ // Should fail since we have not read enough
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), -2);
+ // Should pass after reading two more bytes
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 2);
+ ASSERT_EQ(static_cast<int>(*dest), 8721);
+}
+
+TEST(LlvmLibcMBRToWC, FourByte) {
+ const char ch[4] = {static_cast<char>(0xF0), static_cast<char>(0x9F),
+ static_cast<char>(0xA4),
+ static_cast<char>(0xA1)}; // 🤡 clown emoji
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 4, mb);
+ ASSERT_EQ(static_cast<int>(*dest), 129313);
+ ASSERT_EQ(static_cast<int>(n), 4);
+
+ // Should fail since we have not read enough
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), -2);
+ // Should pass after reading two more bytes
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch + 2, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 2);
+ ASSERT_EQ(static_cast<int>(*dest), 129313);
+}
+
+TEST(LlvmLibcMBRToWC, InvalidByte) {
+ const char ch[1] = {static_cast<char>(0x80)};
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), -1);
+ ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+}
+
+TEST(LlvmLibcMBRToWC, InvalidMultiByte) {
+ const char ch[4] = {static_cast<char>(0x80), static_cast<char>(0x00),
+ static_cast<char>(0x80),
+ static_cast<char>(0x00)}; // invalid sequence of bytes
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ // Trying to push all 4 should error
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 4, mb);
+ ASSERT_EQ(static_cast<int>(n), -1);
+ ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+ // Trying to push just the first one should error
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), -1);
+ ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+ // Trying to push the second and third should correspond to null wc
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch + 1, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 0);
+}
+
+TEST(LlvmLibcMBRToWC, InvalidLastByte) {
+ // Last byte is invalid since it does not have correct starting sequence.
+ // 0xC0 --> 11000000 starting sequence should be 10xxxxxx
+ const char ch[4] = {static_cast<char>(0xF1), static_cast<char>(0x80),
+ static_cast<char>(0x80), static_cast<char>(0xC0)};
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ // Trying to push all 4 should error
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 4, mb);
+ ASSERT_EQ(static_cast<int>(n), -1);
+ ASSERT_EQ(static_cast<int>(libc_errno), EILSEQ);
+}
+
+TEST(LlvmLibcMBRToWC, ValidTwoByteWithExtraRead) {
+ const char ch[3] = {static_cast<char>(0xC2), static_cast<char>(0x8E),
+ static_cast<char>(0x80)};
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ // Trying to push all 3 should return valid 2 byte
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 3, mb);
+ ASSERT_EQ(static_cast<int>(n), 2);
+ ASSERT_EQ(static_cast<int>(*dest), 142);
+}
+
+TEST(LlvmLibcMBRToWC, TwoValidTwoBytes) {
+ const char ch[4] = {static_cast<char>(0xC2), static_cast<char>(0x8E),
+ static_cast<char>(0xC7), static_cast<char>(0x8C)};
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ // mbstate should reset after reading first one
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, ch, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 2);
+ ASSERT_EQ(static_cast<int>(*dest), 142);
+ n = LIBC_NAMESPACE::mbrtowc(dest + 1, ch + 2, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 2);
+ ASSERT_EQ(static_cast<int>(*(dest + 1)), 460);
+}
+
+TEST(LlvmLibcMBRToWC, NullString) {
+ wchar_t dest[2];
+ mbstate_t *mb;
+ LIBC_NAMESPACE::memset(&mb, 0, sizeof(mbstate_t));
+ // reading on nullptr should return 0
+ size_t n = LIBC_NAMESPACE::mbrtowc(dest, nullptr, 2, mb);
+ ASSERT_EQ(static_cast<int>(n), 0);
+ // reading a null terminator should return 0
+ const char *ch = "\0";
+ n = LIBC_NAMESPACE::mbrtowc(dest, ch, 1, mb);
+ ASSERT_EQ(static_cast<int>(n), 0);
+}
|
uzairnawaz
reviewed
Jun 18, 2025
lntue
reviewed
Jun 19, 2025
michaelrj-google
approved these changes
Jun 20, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/131/builds/24439 Here is the relevant piece of the build log for the reference |
Jaddyen
pushed a commit
to Jaddyen/llvm-project
that referenced
this pull request
Jun 23, 2025
implemented the internal and public mbrtowc as well as tests for the public function. --------- Co-authored-by: Sriya Pratipati <[email protected]>
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implemented the internal and public mbrtowc as well as tests for the public function.