From 4d6bc105f7ab6755d05c76f3387160bb8eec0ad8 Mon Sep 17 00:00:00 2001
From: Avi Bryant <avi@avibryant.com>
Date: Sat, 18 Feb 2012 20:40:19 -0800
Subject: [PATCH 1/2] hash(s::ByteString, seed::Uint32)

It's occasionally useful to have control over the seed being used by
the hash algorithm. This adds a hash() method with an extra parameter
to allow this. Currently, it's 32bit only - not sure what the best way
is to allow 64bit as well.
---
 j/table.j             | 3 +++
 src/support/hashing.c | 8 ++++++++
 src/support/hashing.h | 2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/j/table.j b/j/table.j
index b5429d38dcb77..a09a94f80f53c 100644
--- a/j/table.j
+++ b/j/table.j
@@ -129,6 +129,9 @@ else
 hash(s::ByteString) = ccall(:memhash32, Uint32, (Ptr{Void}, Int), s.data, length(s.data))
 end
 
+hash(s::ByteString, seed::Uint32) = ccall(:memhash32_seed, Uint32, (Ptr{Void}, Int, Uint32), s.data, length(s.data), seed)
+
+
 # hash table
 
 type HashTable{K,V} <: Associative
diff --git a/src/support/hashing.c b/src/support/hashing.c
index 0f5a74d370d40..4f369585c86c1 100644
--- a/src/support/hashing.c
+++ b/src/support/hashing.c
@@ -81,3 +81,11 @@ uint32_t memhash32(const char* buf, size_t n)
     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;
+}
diff --git a/src/support/hashing.h b/src/support/hashing.h
index 810b45b0fce31..c1b879ccde68a 100644
--- a/src/support/hashing.h
+++ b/src/support/hashing.h
@@ -12,5 +12,5 @@ DLLEXPORT u_int32_t int64to32hash(u_int64_t key);
 #endif
 DLLEXPORT u_int64_t memhash(const char* buf, size_t n);
 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

From 2d76c20469fcaddad79ba02c6b9033d9c4e63aae Mon Sep 17 00:00:00 2001
From: Avi Bryant <avi@avibryant.com>
Date: Sat, 18 Feb 2012 23:06:32 -0800
Subject: [PATCH 2/2] 64bit version of memhash_seed

The memhash_seed functions now choose 32 vs 64bit hashing the same way
the fixed-seed ones do. Also added them to julia.expmap.
---
 j/table.j             |  3 ++-
 src/julia.expmap      |  2 ++
 src/support/hashing.c | 13 +++++++++++++
 src/support/hashing.h |  1 +
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/j/table.j b/j/table.j
index a09a94f80f53c..6e1a04b3ba554 100644
--- a/j/table.j
+++ b/j/table.j
@@ -125,11 +125,12 @@ 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(s::ByteString, seed::Uint32) = ccall(:memhash32_seed, Uint32, (Ptr{Void}, Int, Uint32), s.data, length(s.data), seed)
 
 
 # hash table
diff --git a/src/julia.expmap b/src/julia.expmap
index 44179f1d9e9f4..fabf4054951d3 100644
--- a/src/julia.expmap
+++ b/src/julia.expmap
@@ -4,7 +4,9 @@
     int64hash;
     int64to32hash;
     memhash;
+    memhash_seed;
     memhash32;
+    memhash32_seed;
     jl_hash_symbol;
     jl_symbol_name;
     jl_uid;
diff --git a/src/support/hashing.c b/src/support/hashing.c
index 4f369585c86c1..e5a4d040e8621 100644
--- a/src/support/hashing.c
+++ b/src/support/hashing.c
@@ -74,6 +74,19 @@ 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;
diff --git a/src/support/hashing.h b/src/support/hashing.h
index c1b879ccde68a..f267f9dcbf519 100644
--- a/src/support/hashing.h
+++ b/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