in include/hash/xxhash.h [4747:4755]
XXH_PUBLIC_API int XXH128_cmp(const void* h128_1, const void* h128_2)
{
XXH128_hash_t const h1 = *(const XXH128_hash_t*)h128_1;
XXH128_hash_t const h2 = *(const XXH128_hash_t*)h128_2;
int const hcmp = (h1.high64 > h2.high64) - (h2.high64 > h1.high64);
/* note : bets that, in most cases, hash values are different */
if (hcmp) return hcmp;
return (h1.low64 > h2.low64) - (h2.low64 > h1.low64);
}