Merge pull request #392 from avibryant/expose-murmurhash-seed

hash(s::ByteString, seed::Uint32)

Author: JeffBezanson

j/table.j

@@ -125,10 +125,14 @@ hash(x::Any) = uid(x)
 
 if WORD_SIZE == 64
 hash(s::ByteString) = ccall(:memhash, Uint64, (Ptr{Void}, Int), s.data, length(s.data))
+hash(s::ByteString, seed::Uint32) = ccall(:memhash_seed, Uint64, (Ptr{Void}, Int, Uint32), s.data, length(s.data), seed)
 else
 hash(s::ByteString) = ccall(:memhash32, Uint32, (Ptr{Void}, Int), s.data, length(s.data))
+hash(s::ByteString, seed::Uint32) = ccall(:memhash32_seed, Uint32, (Ptr{Void}, Int, Uint32), s.data, length(s.data), seed)
 end
 
+
+
 # hash table
 
 type HashTable{K,V} <: Associative

src/julia.expmap

@@ -4,7 +4,9 @@
     int64hash;
     int64to32hash;
     memhash;
+    memhash_seed;
     memhash32;
+    memhash32_seed;
     jl_hash_symbol;
     jl_symbol_name;
     jl_uid;

src/support/hashing.c

@@ -74,10 +74,31 @@ uint64_t memhash(const char* buf, size_t n)
     return out[1];
 }
 
+uint64_t memhash_seed(const char* buf, size_t n, uint32_t seed)
+{
+    uint64_t out[2];
+
+    // TODO: expose 128-bit hash
+#ifdef __LP64__
+    MurmurHash3_x64_128(buf, n, seed, out);
+#else
+    MurmurHash3_x86_128(buf, n, seed, out);
+#endif
+    return out[1];
+}
+
 uint32_t memhash32(const char* buf, size_t n)
 {
     uint32_t out;
 
     MurmurHash3_x86_32(buf, n, _MHASH_SEED_, &out);
     return out;
 }
+
+uint32_t memhash32_seed(const char* buf, size_t n, uint32_t seed)
+{
+    uint32_t out;
+
+    MurmurHash3_x86_32(buf, n, seed, &out);
+    return out;
+}

src/support/hashing.h

@@ -11,6 +11,7 @@ DLLEXPORT u_int32_t int64to32hash(u_int64_t key);
 #define inthash int32hash
 #endif
 DLLEXPORT u_int64_t memhash(const char* buf, size_t n);
+DLLEXPORT u_int64_t memhash_seed(const char* buf, size_t n, u_int32_t seed);
 DLLEXPORT u_int32_t memhash32(const char* buf, size_t n);
-
+DLLEXPORT u_int32_t memhash32_seed(const char* buf, size_t n, u_int32_t seed);
 #endif