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[libc] clean up string_utils memory functions #143031

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Merged
merged 2 commits into from
Jun 6, 2025
Merged

[libc] clean up string_utils memory functions #143031

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077d275
[libc] clean up string_utils memory functions
michaelrj-google Jun 5, 2025
4d0f0c1
fix strsep, remove dependency on cpp::byte
michaelrj-google Jun 5, 2025
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4 changes: 1 addition & 3 deletions libc/src/string/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -15,10 +15,8 @@ add_header_library(
HDRS
string_utils.h
DEPENDS
.memory_utils.inline_bzero
.memory_utils.inline_memcpy
libc.hdr.types.size_t
libc.include.stdlib
libc.hdr.limits_macros
libc.src.__support.CPP.bitset
libc.src.__support.CPP.type_traits
libc.src.__support.common
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11 changes: 5 additions & 6 deletions libc/src/string/string_utils.h
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Expand Up @@ -14,19 +14,19 @@
#ifndef LLVM_LIBC_SRC_STRING_STRING_UTILS_H
#define LLVM_LIBC_SRC_STRING_STRING_UTILS_H

#include "hdr/limits_macros.h"
#include "hdr/types/size_t.h"
#include "src/__support/CPP/bitset.h"
#include "src/__support/CPP/type_traits.h" // cpp::is_same_v
#include "src/__support/macros/config.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
#include "src/string/memory_utils/inline_bzero.h"
#include "src/string/memory_utils/inline_memcpy.h"

namespace LIBC_NAMESPACE_DECL {
namespace internal {

template <typename Word> LIBC_INLINE constexpr Word repeat_byte(Word byte) {
constexpr size_t BITS_IN_BYTE = 8;
static_assert(CHAR_BIT == 8, "repeat_byte assumes a byte is 8 bits.");
constexpr size_t BITS_IN_BYTE = CHAR_BIT;
constexpr size_t BYTE_MASK = 0xff;
Word result = 0;
byte = byte & BYTE_MASK;
Expand Down Expand Up @@ -189,8 +189,7 @@ LIBC_INLINE char *string_token(char *__restrict src,
if (LIBC_UNLIKELY(src == nullptr && ((src = *saveptr) == nullptr)))
return nullptr;

static_assert(sizeof(char) == sizeof(cpp::byte),
"bitset of 256 assumes char is 8 bits");
static_assert(CHAR_BIT == 8, "bitset of 256 assumes char is 8 bits");
cpp::bitset<256> delimiter_set;
for (; *delimiter_string != '\0'; ++delimiter_string)
delimiter_set.set(static_cast<size_t>(*delimiter_string));
Expand Down Expand Up @@ -220,7 +219,7 @@ LIBC_INLINE size_t strlcpy(char *__restrict dst, const char *__restrict src,
if (!size)
return len;
size_t n = len < size - 1 ? len : size - 1;
inline_memcpy(dst, src, n);
__builtin_memcpy(dst, src, n);
dst[n] = '\0';
return len;
}
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2 changes: 2 additions & 0 deletions libc/src/string/strsep.cpp
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Expand Up @@ -12,6 +12,8 @@
#include "src/__support/macros/null_check.h"
#include "src/string/string_utils.h"

#include "src/__support/common.h"

namespace LIBC_NAMESPACE_DECL {

LLVM_LIBC_FUNCTION(char *, strsep,
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3 changes: 2 additions & 1 deletion utils/bazel/llvm-project-overlay/libc/BUILD.bazel
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Expand Up @@ -4188,9 +4188,10 @@ libc_support_library(
deps = [
":__support_common",
":__support_cpp_bitset",
":__support_cpp_type_traits",
":__support_macros_optimization",
":hdr_limits_macros",
":llvm_libc_types_size_t",
":string_memory_utils",
":types_size_t",
],
)
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