remove hash pair

Author: pavel-kirienko

libudpard/udpard.c

@@ -88,21 +88,6 @@ static int64_t     max_i64(const int64_t a, const int64_t b) { return (a > b) ?
 static udpard_us_t earlier(const udpard_us_t a, const udpard_us_t b) { return min_i64(a, b); }
 static udpard_us_t later(const udpard_us_t a, const udpard_us_t b) { return max_i64(a, b); }
 
-/// A simple hash for two u64 arguments based on the SplitMix64 finalizer.
-/// Much better than a simple xor while not being too heavy.
-/// The hashing is only used on internal representations and does not affect wire compatibility.
-static uint64_t hash_pair_u64(const uint64_t a, const uint64_t b)
-{
-    uint64_t x = a ^ (b + 0x9E3779B97F4A7C15ULL);
-    x ^= (a >> 32U) ^ (b << 32U);
-    x ^= x >> 30U;
-    x *= 0xBF58476D1CE4E5B9ULL;
-    x ^= x >> 27U;
-    x *= 0x94D049BB133111EBULL;
-    x ^= x >> 31U;
-    return x;
-}
-
 /// Two memory resources are considered identical if they share the same user pointer and the same allocation function.
 /// The deallocation function is intentionally excluded from the comparison.
 static bool mem_same(const udpard_mem_t a, const udpard_mem_t b)
@@ -1201,7 +1186,7 @@ bool udpard_tx_new(udpard_tx_t* const              self,
         mem_zero(sizeof(*self), self);
         self->vtable                = vtable;
         self->local_uid             = local_uid;
-        self->p2p_transfer_id       = hash_pair_u64(p2p_transfer_id_seed, local_uid);
+        self->p2p_transfer_id       = p2p_transfer_id_seed ^ local_uid; // extra entropy
         self->ack_baseline_timeout  = UDPARD_TX_ACK_BASELINE_TIMEOUT_DEFAULT_us;
         self->enqueued_frames_limit = enqueued_frames_limit;
         self->enqueued_frames_count = 0;