euler/source/std/cstring.cpp


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#include <cstring>

extern "C" void *memset(void *dest, int ch, size_t count) {
  unsigned char c = static_cast<unsigned char>(ch);
  unsigned char *d = (unsigned char *)dest;
  for (size_t i = 0; i < count; ++i)
    d[i] = c;
  return dest;
}

extern "C" void *memcpy(void *dest, const void *src, size_t count) {
  unsigned char *d = (unsigned char *)dest;
  const unsigned char *s = (const unsigned char *)src;
  for (size_t i = 0; i < count; ++i)
    d[i] = s[i];
  return dest;
}

extern "C" int strcmp(const char *lhs, const char *rhs) {
  const unsigned char *l = (const unsigned char *)lhs;
  const unsigned char *r = (const unsigned char *)rhs;
  while (*l == *r) {
    if (*l == 0)
      return 0;
    ++l;
    ++r;
  }
  return *l < *r ? -1 : 1;
}

extern "C" size_t strlen(const char *str) {
  size_t len = 0;
  while (str[len] != '\0')
    ++len;
  return len;
}