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[libc] Cleaned up wcsspn and wcscspn #147408

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[libc] Cleaned up wcsspn and wcscspn #147408

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ab07c55
[libc] Cleaned up wcsspn and wcscspn
Jul 7, 2025
259f776
moved check function to wchar_utils
Jul 7, 2025
d43e66d
moved check_span into namespaces
Jul 7, 2025
ef10e8e
renamed function
Jul 8, 2025
a01af70
simplified logic
Jul 9, 2025
f2a5e8a
added more descriptive comment
Jul 9, 2025
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12 changes: 12 additions & 0 deletions libc/src/wchar/CMakeLists.txt
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Original file line number Diff line number Diff line change
@@ -1,3 +1,13 @@
add_header_library(
wchar_utils
HDRS
wchar_utils.h
DEPENDS
libc.hdr.types.size_t
libc.hdr.types.wchar_t
libc.src.__support.common
)

add_entrypoint_object(
wcslen
SRCS
Expand Down Expand Up @@ -211,6 +221,7 @@ add_entrypoint_object(
DEPENDS
libc.hdr.wchar_macros
libc.hdr.types.size_t
libc.src.wchar.wchar_utils
)

add_entrypoint_object(
Expand All @@ -222,6 +233,7 @@ add_entrypoint_object(
DEPENDS
libc.hdr.wchar_macros
libc.hdr.types.size_t
libc.src.wchar.wchar_utils
)

add_entrypoint_object(
Expand Down
46 changes: 46 additions & 0 deletions libc/src/wchar/wchar_utils.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,46 @@
//===-- wchar utils ---------------------------------------------*- 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_WCHAR_WCHAR_UTILS_H
#define LLVM_LIBC_SRC_WCHAR_WCHAR_UTILS_H

#include "hdr/types/size_t.h"
#include "hdr/types/wchar_t.h"
#include "src/__support/common.h"
#include "src/__support/macros/attributes.h" // LIBC_INLINE

namespace LIBC_NAMESPACE_DECL {
namespace internal {

// returns true if the character exists in the string
LIBC_INLINE bool internal_wcschr(wchar_t c, const wchar_t *str) {
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probably also mark these 2 static. We don't need to export their symbols anyway. Also, since they are already in the internal namespace, just keep their names to wcschr and wcsspn?

for (int n = 0; str[n]; ++n) {
if (str[n] == c)
return true;
}
return false;
}

// To avoid duplicated code, call this with true for wcscspn and call with false
// for wcsspn
LIBC_INLINE size_t inline_wcsspn(const wchar_t *s1, const wchar_t *s2,
bool invert) {
size_t i = 0;
for (; s1[i]; ++i) {
bool check = internal_wcschr(s1[i], s2);
check = invert ? !check : check;
if (!check)
return i;
}
return i;
}

} // namespace internal
} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC_WCHAR_WCHAR_UTILS_H
15 changes: 2 additions & 13 deletions libc/src/wchar/wcscspn.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,23 +12,12 @@
#include "hdr/types/wchar_t.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "wchar_utils.h"

namespace LIBC_NAMESPACE_DECL {

bool check(wchar_t c, const wchar_t *s2) {
for (int n = 0; s2[n]; ++n) {
if (s2[n] == c)
return false;
}
return true;
}
LLVM_LIBC_FUNCTION(size_t, wcscspn, (const wchar_t *s1, const wchar_t *s2)) {
size_t i = 0;
for (; s1[i]; ++i) {
if (!check(s1[i], s2))
return i;
}
return i;
return internal::inline_wcsspn(s1, s2, true);
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Since you are here, can you also add LIBC_CRASH_ON_NULLPTR(s1) and LIBC_CRASH_ON_NULLPTR(s2), and add comment on the name of the third argument /*not_match_set=*/ true.

}

} // namespace LIBC_NAMESPACE_DECL
15 changes: 2 additions & 13 deletions libc/src/wchar/wcsspn.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,23 +12,12 @@
#include "hdr/types/wchar_t.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "wchar_utils.h"

namespace LIBC_NAMESPACE_DECL {

bool check(wchar_t c, const wchar_t *s2) {
for (int n = 0; s2[n]; ++n) {
if (s2[n] == c)
return true;
}
return false;
}
LLVM_LIBC_FUNCTION(size_t, wcsspn, (const wchar_t *s1, const wchar_t *s2)) {
size_t i = 0;
for (; s1[i]; ++i) {
if (!check(s1[i], s2))
return i;
}
return i;
return internal::inline_wcsspn(s1, s2, false);
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ditto

}

} // namespace LIBC_NAMESPACE_DECL
13 changes: 13 additions & 0 deletions utils/bazel/llvm-project-overlay/libc/BUILD.bazel
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Expand Up @@ -5729,6 +5729,17 @@ libc_function(

############################## wchar targets ###############################

libc_support_library(
name = "wchar_utils",
hdrs = ["src/wchar/wchar_utils.h"],
deps = [
":__support_common",
":__support_macros_attributes",
":types_size_t",
":types_wchar_t",
],
)

libc_function(
name = "btowc",
srcs = ["src/wchar/btowc.cpp"],
Expand Down Expand Up @@ -5826,6 +5837,7 @@ libc_function(
":__support_macros_config",
":types_size_t",
":types_wchar_t",
":wchar_utils",
],
)

Expand Down Expand Up @@ -5911,6 +5923,7 @@ libc_function(
":__support_macros_config",
":types_size_t",
":types_wchar_t",
":wchar_utils",
],
)

Expand Down
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