Adds seed parameter to CityHash32.

- city32's known bad seed is added back to g_hashes.

City.cpp

@@ -156,20 +156,19 @@ static uint32_t Mur(uint32_t a, uint32_t h) {
   return h * 5 + 0xe6546b64;
 }
 
-static uint32_t Hash32Len13to24(const char *s, size_t len) {
+static uint32_t Hash32Len13to24(const char *s, size_t len, uint32_t seed) {
   uint32_t a = Fetch32(s - 4 + (len >> 1));
   uint32_t b = Fetch32(s + 4);
   uint32_t c = Fetch32(s + len - 8);
   uint32_t d = Fetch32(s + (len >> 1));
   uint32_t e = Fetch32(s);
   uint32_t f = Fetch32(s + len - 4);
-  uint32_t h = static_cast<uint32_t>(len);
-
+  uint32_t h = static_cast<uint32_t>(len + seed);
   return fmix(Mur(f, Mur(e, Mur(d, Mur(c, Mur(b, Mur(a, h)))))));
 }
 
-static uint32_t Hash32Len0to4(const char *s, size_t len) {
-  uint32_t b = 0;
+static uint32_t Hash32Len0to4(const char *s, size_t len, uint32_t seed) {
+  uint32_t b = seed;
   uint32_t c = 9;
   for (size_t i = 0; i < len; i++) {
     signed char v = static_cast<signed char>(s[i]);
@@ -179,23 +178,23 @@ static uint32_t Hash32Len0to4(const char *s, size_t len) {
   return fmix(Mur(b, Mur(static_cast<uint32_t>(len), c)));
 }
 
-static uint32_t Hash32Len5to12(const char *s, size_t len) {
-  uint32_t a = static_cast<uint32_t>(len), b = a * 5, c = 9, d = b;
+static uint32_t Hash32Len5to12(const char *s, size_t len, uint32_t seed) {
+  uint32_t a = static_cast<uint32_t>(len + seed), b = a * 5, c = 9, d = b;
   a += Fetch32(s);
   b += Fetch32(s + len - 4);
   c += Fetch32(s + ((len >> 1) & 4));
   return fmix(Mur(c, Mur(b, Mur(a, d))));
 }
 
-uint32_t CityHash32(const char *s, size_t len) {
+uint32_t CityHash32WithSeed(const char *s, size_t len, uint32_t seed) {
   if (len <= 24) {
     return len <= 12
-               ? (len <= 4 ? Hash32Len0to4(s, len) : Hash32Len5to12(s, len))
-               : Hash32Len13to24(s, len);
+               ? (len <= 4 ? Hash32Len0to4(s, len, seed) : Hash32Len5to12(s, len, seed))
+               : Hash32Len13to24(s, len, seed);
   }
 
   // len > 24
-  uint32_t h = static_cast<uint32_t>(len), g = c1 * h, f = g;
+  uint32_t h = static_cast<uint32_t>(len + seed), g = c1 * h, f = g;
   uint32_t a0 = Rotate32(Fetch32(s + len - 4) * c1, 17) * c2;
   uint32_t a1 = Rotate32(Fetch32(s + len - 8) * c1, 17) * c2;
   uint32_t a2 = Rotate32(Fetch32(s + len - 16) * c1, 17) * c2;

City.h

@@ -55,7 +55,7 @@ inline uint64_t Uint128Low64(const uint128 &x) { return x.first; }
 inline uint64_t Uint128High64(const uint128 &x) { return x.second; }
 
 // Hash functions for a byte array.
-uint32_t CityHash32(const char *buf, size_t len);
+uint32_t CityHash32WithSeed(const char *buf, size_t len, uint32_t seed);
 uint64_t CityHash64(const char *buf, size_t len);
 
 // Hash function for a byte array.  For convenience, a 64-bit seed is also

CityTest.cpp

@@ -3,8 +3,7 @@
 
 void CityHash32_test(const void *key, int len, uint32_t seed, void *out) {
   // objsize 0-527: 1319
-  *(uint32_t *)out = CityHash32((const char *)key, len);
-  (void)seed;
+  *(uint32_t *)out = CityHash32WithSeed((const char *)key, len, seed);
 }
 
 void CityHash64_test(const void *key, int len, uint32_t seed, void *out) {

main.cpp

@@ -354,7 +354,7 @@ HashInfo g_hashes[] =
 #  endif
 # endif
 #endif
-{ CityHash32_test,      32, 0x68254F81, "City32",      "Google CityHash32 (v1.1)", POOR, {} /* !! */},
+{ CityHash32_test,      32, 0xEDED9084, "City32",      "Google CityHash32WithSeed (v1.1)", POOR, {0x2eb38c9f} /* !! */},
 #ifdef HAVE_INT64
 { metrohash64_test,      64, 0x6FA828C9, "metrohash64",    "MetroHash64, 64-bit", POOR, {} },
 { metrohash64_1_test,    64, 0xEE88F7D2, "metrohash64_1",  "MetroHash64_1, 64-bit (legacy)", POOR, {} },