libc/src/string/memory_utils/inline_strcmp.h

//===-- str{,case}cmp implementation ----------------------------*- 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_STRING_MEMORY_UTILS_INLINE_STRCMP_H
#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_STRCMP_H

#include "src/__support/macros/attributes.h" // LIBC_INLINE
#include "src/__support/macros/config.h"     // LIBC_NAMESPACE_DECL
#include <stddef.h>

namespace LIBC_NAMESPACE_DECL {

template <typename Comp>
LIBC_INLINE constexpr int inline_strcmp(const char *left, const char *right,
                                        Comp &&comp) {
  // TODO: Look at benefits for comparing words at a time.
  for (; *left && !comp(*left, *right); ++left, ++right)
    ;
  return comp(*reinterpret_cast<const unsigned char *>(left),
              *reinterpret_cast<const unsigned char *>(right));
}

template <typename Comp>
LIBC_INLINE constexpr int inline_strncmp(const char *left, const char *right,
                                         size_t n, Comp &&comp) {
  if (n == 0)
    return 0;

  // TODO: Look at benefits for comparing words at a time.
  for (; n > 1; --n, ++left, ++right) {
    char lc = *left;
    if (!comp(lc, '\0') || comp(lc, *right))
      break;
  }
  return comp(*reinterpret_cast<const unsigned char *>(left),
              *reinterpret_cast<const unsigned char *>(right));
}

} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_STRCMP_H