libc/bionic/casecmp.cpp

/*
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#include <ctype.h>
#include <stddef.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>

// We don't use the llvm-libc routines because they don't just call out to
// tolower()/towlower(), preferring their own implementations, which don't
// match ours.

// We can also make all the _l() variants simple aliases for the regular
// functions, since bionic doesn't implement locales (because if you're
// serious about i18n, you want icu anyway).

template <typename CharT, typename MapperFn>
int CaseCmp(const CharT* lhs, const CharT* rhs, MapperFn mapper) {
  while (*lhs && mapper(*lhs) == mapper(*rhs)) {
    lhs++;
    rhs++;
  }
  return static_cast<unsigned>(mapper(*lhs)) - static_cast<unsigned>(mapper(*rhs));
}

template <typename CharT, typename MapperFn>
int CaseCmp(const CharT* lhs, const CharT* rhs, size_t n, MapperFn mapper) {
  if (n-- == 0) return 0;
  while (*lhs && *rhs && n > 0 && mapper(*lhs) == mapper(*rhs)) {
    if (*lhs == '\0') return 0;
    lhs++;
    rhs++;
    n--;
  }
  return static_cast<unsigned>(mapper(*lhs)) - static_cast<unsigned>(mapper(*rhs));
}

int strcasecmp(const char* lhs, const char* rhs) {
  return CaseCmp(lhs, rhs, tolower);
}
__strong_alias(strcasecmp_l, strcasecmp);

int strncasecmp(const char* lhs, const char* rhs, size_t n) {
  return CaseCmp(lhs, rhs, n, tolower);
}
__strong_alias(strncasecmp_l, strncasecmp);

int wcscasecmp(const wchar_t* lhs, const wchar_t* rhs) {
  return CaseCmp(lhs, rhs, towlower);
}
__strong_alias(wcscasecmp_l, wcscasecmp);

int wcsncasecmp(const wchar_t* lhs, const wchar_t* rhs, size_t n) {
  return CaseCmp(lhs, rhs, n, towlower);
}
__strong_alias(wcsncasecmp_l, wcsncasecmp);