libc/src/string/memory_utils/inline_strcmp.h

   1 //===-- str{,case}cmp implementation ----------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_STRCMP_H
  10 #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_STRCMP_H
  11
  12 #include <stddef.h>
  13
  14 namespace LIBC_NAMESPACE {
  15
  16 template <typename Comp>
  17 LIBC_INLINE constexpr int inline_strcmp(const char *left, const char *right,
  18                                         Comp &&comp) {
  19   // TODO: Look at benefits for comparing words at a time.
  20   for (; *left && !comp(*left, *right); ++left, ++right)
  21     ;
  22   return comp(*reinterpret_cast<const unsigned char *>(left),
  23               *reinterpret_cast<const unsigned char *>(right));
  24 }
  25
  26 template <typename Comp>
  27 LIBC_INLINE constexpr int inline_strncmp(const char *left, const char *right,
  28                                          size_t n, Comp &&comp) {
  29   if (n == 0)
  30     return 0;
  31
  32   // TODO: Look at benefits for comparing words at a time.
  33   for (; n > 1; --n, ++left, ++right) {
  34     char lc = *left;
  35     if (!comp(lc, '\0') || comp(lc, *right))
  36       break;
  37   }
  38   return comp(*reinterpret_cast<const unsigned char *>(left),
  39               *reinterpret_cast<const unsigned char *>(right));
  40 }
  41
  42 } // namespace LIBC_NAMESPACE
  43
  44 #endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_INLINE_STRCMP_H