From 70decdb703f5d053da3dbe349e9a7328a14aa1f2 Mon Sep 17 00:00:00 2001
From: Tyge Løvset <tylo@norceresearch.no>
Date: Mon, 10 Aug 2020 10:43:12 +0200
Subject: Updated hash funcs.

---
 examples/benchmark.c | 11 +++++------
 stc/cmap.h           | 22 +++++-----------------
 stc/crandom.h        |  5 +++--
 3 files changed, 13 insertions(+), 25 deletions(-)

diff --git a/examples/benchmark.c b/examples/benchmark.c
index 52aa8353..30fb48af 100644
--- a/examples/benchmark.c
+++ b/examples/benchmark.c
@@ -15,11 +15,10 @@
 // Visual Studio: compile with -TP to force C++:  cl -TP -EHsc -O2 benchmark.c
 
 static inline uint32_t fibfast_hash(const void* data, size_t len) {
-    const uint64_t key = *(const uint64_t *) data;
-    return (uint32_t) (key * 11400714819323198485llu);
+    return (*(const uint64_t *) data) * 11400714819323198485llu;
 }
 
-declare_cmap(ii, int64_t, int64_t, c_default_destroy, c_default_equals, fibfast_hash); // c_fibonacci_hash64);
+declare_cmap(ii, int64_t, int64_t, c_default_destroy, c_default_equals, fibfast_hash); // c_default_hash32);
 
 KHASH_MAP_INIT_INT64(ii, uint64_t)
 
@@ -143,7 +142,7 @@ int main(int argc, char* argv[])
     printf("\nRandom keys are in range [0, 2^%d), seed = %zu:\n",  rr, seed);
     printf("\nUnordered maps: %zu repeats of Insert random key + try to remove a random key:\n", N1);
     MAP_TEST1(CMAP, ii)
-    MAP_TEST1(KMAP, ii)
+    //MAP_TEST1(KMAP, ii)
 #ifdef __cplusplus
     MAP_TEST1(UMAP, ii)
     MAP_TEST1(BMAP, ii)
@@ -153,7 +152,7 @@ int main(int argc, char* argv[])
 
     printf("\nUnordered maps: Insert %zu index keys, then remove them in same order:\n", N2);
     MAP_TEST2(CMAP, ii)
-    MAP_TEST2(KMAP, ii)
+    //MAP_TEST2(KMAP, ii)
 #ifdef __cplusplus
     MAP_TEST2(UMAP, ii)
     MAP_TEST2(BMAP, ii)
@@ -163,7 +162,7 @@ int main(int argc, char* argv[])
 
     printf("\nUnordered maps: Insert %zu random keys, then remove them in same order:\n", N3);
     MAP_TEST3(CMAP, ii)
-    MAP_TEST3(KMAP, ii)
+    //MAP_TEST3(KMAP, ii)
 #ifdef __cplusplus
     MAP_TEST3(UMAP, ii)
     MAP_TEST3(BMAP, ii)
diff --git a/stc/cmap.h b/stc/cmap.h
index 08986f29..dfb845a2 100644
--- a/stc/cmap.h
+++ b/stc/cmap.h
@@ -379,32 +379,20 @@ ctype##_##tag##_next(ctype##_##tag##_iter_t* it) { \
     while (++it->item != it->end && *++it->_hx == 0) ; \
 }
 
-
-/* One-byte-at-a-time hash based on Murmur's mix */
-STC_API uint32_t c_default_hash(const void *data, size_t len) {
-    const volatile uint8_t *key = (const uint8_t *) data;
-    uint32_t x = UINT32_C(0xc613fc15);
-    while (len--) {
-        x ^= *key++;
-        x *= UINT32_C(0x5bd1e995);
-        x ^= x >> 15;
-    }
+STC_API uint32_t  c_default_hash(const void *data, size_t len) {
+    const volatile uint16_t *key = (const uint16_t *) data;
+    uint64_t x = 0xc613fc15u;
+    while (len -= 2) x = ((*key++ + x) * 2654435769u) >> 13;
     return x;
 }
 /* https://programmingpraxis.com/2018/06/19/fibonacci-hash */
 /* https://probablydance.com/2018/06/16/fibonacci-hashing-the-optimization-that-the-world-forgot-or-a-better-alternative-to-integer-modulo/ */
-STC_API uint32_t c_fibonacci_hash32(const void* data, size_t len) {
+STC_API uint32_t c_default_hash32(const void* data, size_t len) {
     const volatile uint32_t *key = (const uint32_t *) data;
     uint32_t x = *key++ * 2654435769u;
     while (len -= 4) x ^= *key++ * 2654435769u;
     return x;
 }
-STC_API uint32_t c_fibonacci_hash64(const void* data, size_t len) {
-    const volatile uint64_t *key = (const uint64_t *) data;
-    uint64_t x = *key++ * 11400714819323198485ull;
-    while (len -= 8) x ^= *key++ * 11400714819323198485ull;
-    return (uint32_t) x; // (x >> 13);
-}
 
 #else
 #define implement_CHASH(tag, ctype, Key, Value, valueDestroy, keyEqualsRaw, keyHashRaw, \
diff --git a/stc/crandom.h b/stc/crandom.h
index 96a07fc4..1e3b2107 100644
--- a/stc/crandom.h
+++ b/stc/crandom.h
@@ -97,8 +97,9 @@ STC_INLINE crandom_distrib_i64_t crandom_uniform_i64_init(int64_t low, int64_t h
 STC_INLINE int64_t crandom_uniform_i64(crandom_eng64_t* rng, crandom_distrib_i64_t dist) {
 #if defined(__SIZEOF_INT128__)
     return dist.offset + (int64_t) (((__uint128_t) crandom_i64(rng) * dist.range) >> 64);
-#elif defined(_MSC_VER)
-    int64_t hi; _mul128(crandom_i64(rng) >> 1, dist.range << 1, &hi); return dist.offset + hi;
+
+#elif defined(_MSC_VER) && defined(_WIN64)
+    int64_t hi; _umul128(crandom_i64(rng), dist.range, &hi); return dist.offset + hi;
 #else
     return dist.offset + crandom_i64(rng) % dist.range; // slower
 #endif
-- 
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