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[libc] Fix wcstok() "subsequent searches" behavior. #151589

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Merged
merged 2 commits into from
Aug 1, 2025
Merged

[libc] Fix wcstok() "subsequent searches" behavior. #151589

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4fc9801
[libc] Fix wcstok() "subsequent searches" behavior.
enh-google Jul 31, 2025
10d198b
[libc] test wcstok() "subsequent searches" behavior.
enh-google Jul 31, 2025
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13 changes: 9 additions & 4 deletions libc/src/wchar/wcstok.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -27,17 +27,22 @@ LLVM_LIBC_FUNCTION(wchar_t *, wcstok,
wchar_t *tok_start = str;
while (*tok_start != L'\0' && internal::wcschr(delims, *tok_start))
++tok_start;
if (*tok_start == L'\0') {
*context = nullptr;
return nullptr;
}

wchar_t *tok_end = tok_start;
while (*tok_end != L'\0' && !internal::wcschr(delims, *tok_end))
++tok_end;

if (*tok_end != L'\0') {
if (*tok_end == L'\0') {
*context = nullptr;
} else {
*tok_end = L'\0';
++tok_end;
*context = tok_end + 1;
}
*context = tok_end;
return *tok_start == L'\0' ? nullptr : tok_start;
return tok_start;
}

} // namespace LIBC_NAMESPACE_DECL
8 changes: 8 additions & 0 deletions libc/test/src/wchar/wcstok_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@ TEST(LlvmLibcWCSTokReentrantTest, NoTokenFound) {
// Another call to ensure that 'reserve' is not in a bad state.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(empty, L"", &reserve), nullptr);
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"", &reserve), nullptr);
// Subsequent searches still return nullptr.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"", &reserve), nullptr);
}
{ // Empty source and single character delimiter string.
wchar_t empty[] = L"";
Expand All @@ -27,6 +29,8 @@ TEST(LlvmLibcWCSTokReentrantTest, NoTokenFound) {
// Another call to ensure that 'reserve' is not in a bad state.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(empty, L"_", &reserve), nullptr);
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"_", &reserve), nullptr);
// Subsequent searches still return nullptr.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"_", &reserve), nullptr);
}
{ // Same character source and delimiter string.
wchar_t single[] = L"_";
Expand All @@ -35,6 +39,8 @@ TEST(LlvmLibcWCSTokReentrantTest, NoTokenFound) {
// Another call to ensure that 'reserve' is not in a bad state.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(single, L"_", &reserve), nullptr);
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"_", &reserve), nullptr);
// Subsequent searches still return nullptr.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L"_", &reserve), nullptr);
}
{ // Multiple character source and single character delimiter string.
wchar_t multiple[] = L"1,2";
Expand All @@ -51,6 +57,8 @@ TEST(LlvmLibcWCSTokReentrantTest, NoTokenFound) {
ASSERT_TRUE(tok[2] == L'2');
ASSERT_TRUE(tok[3] == L'\0');
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L":", &reserve), nullptr);
// Subsequent searches still return nullptr.
ASSERT_EQ(LIBC_NAMESPACE::wcstok(nullptr, L":", &reserve), nullptr);
}
}

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