[libc-commits] [libc] ac7e391 - [libc] Implemented wcsnlen (#145610)
via libc-commits
libc-commits at lists.llvm.org
Fri Jun 27 09:51:40 PDT 2025
Author: sribee8
Date: 2025-06-27T16:51:37Z
New Revision: ac7e3910350aed59495883d4193275106047645f
URL: https://github.com/llvm/llvm-project/commit/ac7e3910350aed59495883d4193275106047645f
DIFF: https://github.com/llvm/llvm-project/commit/ac7e3910350aed59495883d4193275106047645f.diff
LOG: [libc] Implemented wcsnlen (#145610)
Implemented wcsnlen and tests for the function.
---------
Co-authored-by: Sriya Pratipati <sriyap at google.com>
Added:
libc/src/wchar/wcsnlen.cpp
libc/src/wchar/wcsnlen.h
libc/test/src/wchar/wcsnlen_test.cpp
Modified:
libc/config/linux/x86_64/entrypoints.txt
libc/include/wchar.yaml
libc/src/wchar/CMakeLists.txt
libc/test/src/wchar/CMakeLists.txt
Removed:
################################################################################
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 6b3fc9485ec1a..7a954a480e698 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -366,6 +366,7 @@ set(TARGET_LIBC_ENTRYPOINTS
# wchar.h entrypoints
libc.src.wchar.btowc
libc.src.wchar.wcslen
+ libc.src.wchar.wcsnlen
libc.src.wchar.wctob
libc.src.wchar.wmemmove
libc.src.wchar.wmemset
diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index 397296894829d..9e862ff984494 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -17,6 +17,13 @@ functions:
return_type: size_t
arguments:
- type: const wchar_t *
+ - name: wcsnlen
+ standards:
+ - stdc
+ return_type: size_t
+ arguments:
+ - type: const wchar_t *
+ - type: size_t
- name: wctob
standards:
- stdc
diff --git a/libc/src/wchar/CMakeLists.txt b/libc/src/wchar/CMakeLists.txt
index 16664100d42c7..867aab6755bf6 100644
--- a/libc/src/wchar/CMakeLists.txt
+++ b/libc/src/wchar/CMakeLists.txt
@@ -10,6 +10,17 @@ add_entrypoint_object(
libc.src.string.string_utils
)
+add_entrypoint_object(
+ wcsnlen
+ SRCS
+ wcsnlen.cpp
+ HDRS
+ wcsnlen.h
+ DEPENDS
+ libc.hdr.types.size_t
+ libc.hdr.types.wchar_t
+)
+
add_entrypoint_object(
wctob
SRCS
diff --git a/libc/src/wchar/wcsnlen.cpp b/libc/src/wchar/wcsnlen.cpp
new file mode 100644
index 0000000000000..4613006ff203e
--- /dev/null
+++ b/libc/src/wchar/wcsnlen.cpp
@@ -0,0 +1,25 @@
+//===-- Implementation of wcsnlen -----------------------------------------===//
+//
+// 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/wcsnlen.h"
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(size_t, wcsnlen, (const wchar_t *src, size_t maxlen)) {
+ size_t i = 0;
+ for (; i < maxlen && src[i]; ++i)
+ ;
+ return i;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/wcsnlen.h b/libc/src/wchar/wcsnlen.h
new file mode 100644
index 0000000000000..5a4c92d368a54
--- /dev/null
+++ b/libc/src/wchar/wcsnlen.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for wcsnlen ---------------------------------===//
+//
+// 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_WCSNLEN_H
+#define LLVM_LIBC_SRC_WCHAR_WCSNLEN_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 wcsnlen(const wchar_t *src, size_t maxlen);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WCSNLEN_H
diff --git a/libc/test/src/wchar/CMakeLists.txt b/libc/test/src/wchar/CMakeLists.txt
index bf16fdd7f8c4d..02949c68d81dd 100644
--- a/libc/test/src/wchar/CMakeLists.txt
+++ b/libc/test/src/wchar/CMakeLists.txt
@@ -12,6 +12,18 @@ add_libc_test(
libc.src.wchar.wcslen
)
+add_libc_test(
+ wcsnlen_test
+ SUITE
+ libc_wchar_unittests
+ SRCS
+ wcsnlen_test.cpp
+ DEPENDS
+ libc.hdr.types.size_t
+ libc.hdr.types.wchar_t
+ libc.src.wchar.wcsnlen
+)
+
add_libc_test(
btowc_test
SUITE
diff --git a/libc/test/src/wchar/wcsnlen_test.cpp b/libc/test/src/wchar/wcsnlen_test.cpp
new file mode 100644
index 0000000000000..efb7198a31154
--- /dev/null
+++ b/libc/test/src/wchar/wcsnlen_test.cpp
@@ -0,0 +1,54 @@
+//===-- Unittests for wcsnlen ---------------------------------------------===//
+//
+// 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/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/wchar/wcsnlen.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWCSNLenTest, EmptyString) {
+ ASSERT_EQ(static_cast<size_t>(0), LIBC_NAMESPACE::wcsnlen(L"", 0));
+ // If N is greater than string length, this should still return 0.
+ ASSERT_EQ(static_cast<size_t>(0), LIBC_NAMESPACE::wcsnlen(L"", 1));
+}
+
+TEST(LlvmLibcWCSNLenTest, OneCharacterString) {
+ const wchar_t *src = L"A";
+ ASSERT_EQ(static_cast<size_t>(1), LIBC_NAMESPACE::wcsnlen(src, 1));
+ // If N is 0, this should return 0.
+ ASSERT_EQ(static_cast<size_t>(0), LIBC_NAMESPACE::wcsnlen(src, 0));
+ // If N is greater than string length, this should still return 1.
+ ASSERT_EQ(static_cast<size_t>(1), LIBC_NAMESPACE::wcsnlen(src, 3));
+}
+
+TEST(LlvmLibcWCSNLenTest, ManyCharacterString) {
+ const wchar_t *src = L"123456789";
+ ASSERT_EQ(static_cast<size_t>(9), LIBC_NAMESPACE::wcsnlen(src, 9));
+ // If N is 0, this should return 0.
+ ASSERT_EQ(static_cast<size_t>(0), LIBC_NAMESPACE::wcsnlen(src, 0));
+ // If N is smaller than the string length, it should return N.
+ ASSERT_EQ(static_cast<size_t>(3), LIBC_NAMESPACE::wcsnlen(src, 3));
+ // If N is greater than string length, this should still return 9.
+ ASSERT_EQ(static_cast<size_t>(9), LIBC_NAMESPACE::wcsnlen(src, 42));
+}
+
+TEST(LlvmLibcWCSNLenTest, IgnoreCharactersAfterNullTerminator) {
+ const wchar_t src[5] = {L'a', L'b', L'c', L'\0', L'd'};
+ ASSERT_EQ(static_cast<size_t>(3), LIBC_NAMESPACE::wcsnlen(src, 3));
+ // This should only read up to the null terminator.
+ ASSERT_EQ(static_cast<size_t>(3), LIBC_NAMESPACE::wcsnlen(src, 4));
+ ASSERT_EQ(static_cast<size_t>(3), LIBC_NAMESPACE::wcsnlen(src, 5));
+}
+
+TEST(LlvmLibcWCSNLenTest, NoNullTerminator) {
+ const wchar_t src[4] = {L'a', L'b', L'c', L'd'};
+ // Should return 4
+ ASSERT_EQ(static_cast<size_t>(4), LIBC_NAMESPACE::wcsnlen(src, 4));
+ // Should return 2 since N is smaller than string length
+ ASSERT_EQ(static_cast<size_t>(2), LIBC_NAMESPACE::wcsnlen(src, 2));
+}
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