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[libc] wcpncpy implementation (#145430)

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Implemented wcpncpy and tests.

---------

Co-authored-by: Sriya Pratipati <sriyap@google.com>
This commit is contained in:
sribee8
2025-06-23 16:35:28 -07:00
committed by GitHub
parent 10d46cf0d5
commit bc5e5c0114
7 changed files with 174 additions and 0 deletions
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1
libc/config/linux/x86_64/entrypoints.txt
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@@ -385,6 +385,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.wchar.wcscpy
libc.src.wchar.wmemchr
libc.src.wchar.wcpcpy
libc.src.wchar.wcpncpy
# sys/uio.h entrypoints
libc.src.sys.uio.writev

8
libc/include/wchar.yaml
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@@ -189,3 +189,11 @@ functions:
arguments:
- type: wchar_t *__restrict
- type: const wchar_t *__restrict
- name: wcpncpy
standards:
- stdc
return_type: wchar_t *
arguments:
- type: wchar_t *__restrict
- type: const wchar_t *__restrict
- type: size_t

12
libc/src/wchar/CMakeLists.txt
View File

@@ -104,6 +104,18 @@ add_entrypoint_object(
libc.src.string.string_utils
)
add_entrypoint_object(
wcpncpy
SRCS
wcpncpy.cpp
HDRS
wcpncpy.h
DEPENDS
libc.hdr.types.size_t
libc.hdr.wchar_macros
libc.src.__support.macros.null_check
)
add_entrypoint_object(
wcschr
SRCS

36
libc/src/wchar/wcpncpy.cpp Normal file
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@@ -0,0 +1,36 @@
//===-- Implementation of wcpncpy -----------------------------------------===//
//
// 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/wcpncpy.h"
#include "hdr/types/size_t.h"
#include "hdr/types/wchar_t.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "src/__support/macros/null_check.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(wchar_t *, wcpncpy,
(wchar_t *__restrict s1, const wchar_t *__restrict s2,
size_t n)) {
if (n) {
LIBC_CRASH_ON_NULLPTR(s1);
LIBC_CRASH_ON_NULLPTR(s2);
}
size_t i;
// Copy up until \0 is found.
for (i = 0; i < n && s2[i] != '\0'; ++i)
s1[i] = s2[i];
// When n>strlen(src), n-strlen(src) \0 are appended.
for (; i < n; ++i)
s1[i] = L'\0';
return s1 + i;
}
} // namespace LIBC_NAMESPACE_DECL

23
libc/src/wchar/wcpncpy.h Normal file
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@@ -0,0 +1,23 @@
//===-- Implementation header for wcpncpy ---------------------------------===//
//
// 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_WCPNCPY_H
#define LLVM_LIBC_SRC_WCHAR_WCPNCPY_H
#include "hdr/types/size_t.h"
#include "hdr/types/wchar_t.h"
#include "src/__support/macros/config.h"
namespace LIBC_NAMESPACE_DECL {
wchar_t *wcpncpy(wchar_t *__restrict ws1, const wchar_t *__restrict ws2,
size_t n);
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_WCHAR_WCPNsCPY_H

10
libc/test/src/wchar/CMakeLists.txt
View File

@@ -255,3 +255,13 @@ add_libc_test(
DEPENDS
libc.src.wchar.wcpcpy
)
add_libc_test(
wcpncpy_test
SUITE
libc_wchar_unittests
SRCS
wcpncpy_test.cpp
DEPENDS
libc.src.wchar.wcpncpy
)

84
libc/test/src/wchar/wcpncpy_test.cpp Normal file
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@@ -0,0 +1,84 @@
//===-- Unittests for wcpncpy --------------------------------------------===//
//
// 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/wchar_t.h"
#include "src/wchar/wcpncpy.h"
#include "test/UnitTest/Test.h"
TEST(LlvmLibcWCPNCpyTest, EmptySrc) {
// Empty src should lead to empty destination.
wchar_t dest[4] = {L'a', L'b', L'c', L'\0'};
const wchar_t *src = L"";
LIBC_NAMESPACE::wcpncpy(dest, src, 3);
ASSERT_TRUE(dest[0] == src[0]);
ASSERT_TRUE(dest[0] == L'\0');
// Rest should also be padded with L'\0'
ASSERT_TRUE(dest[1] == L'\0');
ASSERT_TRUE(dest[2] == L'\0');
}
TEST(LlvmLibcWCPNCpyTest, Untouched) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'x', L'\0'};
LIBC_NAMESPACE::wcpncpy(dest, src, 0);
ASSERT_TRUE(dest[0] == L'a');
ASSERT_TRUE(dest[1] == L'b');
}
TEST(LlvmLibcWCPNCpyTest, CopyOne) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'x', L'y'};
wchar_t *res = LIBC_NAMESPACE::wcpncpy(dest, src, 1);
ASSERT_TRUE(dest[0] == L'x');
ASSERT_TRUE(dest[1] == L'b');
ASSERT_EQ(dest + 1, res);
}
TEST(LlvmLibcWCPNCpyTest, CopyNull) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'\0', L'y'};
wchar_t *res = LIBC_NAMESPACE::wcpncpy(dest, src, 1);
ASSERT_TRUE(dest[0] == L'\0');
ASSERT_TRUE(dest[1] == L'b');
ASSERT_EQ(dest + 1, res);
}
TEST(LlvmLibcWCPNCpyTest, CopyPastSrc) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'\0', L'y'};
wchar_t *res = LIBC_NAMESPACE::wcpncpy(dest, src, 2);
ASSERT_TRUE(dest[0] == L'\0');
ASSERT_TRUE(dest[1] == L'\0');
ASSERT_EQ(dest + 2, res);
}
TEST(LlvmLibcWCPNCpyTest, CopyTwoNoNull) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'x', L'y'};
wchar_t *res = LIBC_NAMESPACE::wcpncpy(dest, src, 2);
ASSERT_TRUE(dest[0] == L'x');
ASSERT_TRUE(dest[1] == L'y');
ASSERT_EQ(dest + 2, res);
}
TEST(LlvmLibcWCPNCpyTest, CopyTwoWithNull) {
wchar_t dest[] = {L'a', L'b'};
const wchar_t src[] = {L'x', L'\0'};
wchar_t *res = LIBC_NAMESPACE::wcpncpy(dest, src, 2);
ASSERT_TRUE(dest[0] == L'x');
ASSERT_TRUE(dest[1] == L'\0');
ASSERT_EQ(dest + 2, res);
}
#if defined(LIBC_ADD_NULL_CHECKS) && !defined(LIBC_HAS_SANITIZER)
TEST(LlvmLibcWCPNCpyTest, NullptrCrash) {
// Passing in a nullptr should crash the program.
EXPECT_DEATH([] { LIBC_NAMESPACE::wcpncpy(nullptr, nullptr, 1); },
WITH_SIGNAL(-1));
}
#endif // LIBC_HAS_ADDRESS_SANITIZER