1 files changed, 43 insertions, 0 deletions
diff --git a/src/uint256.cpp b/src/uint256.cpp
index 3392f1e9bc..08c05594fd 100644
--- a/src/uint256.cpp
+++ b/src/uint256.cpp
@@ -290,3 +290,46 @@ uint32_t uint256::GetCompact(bool fNegative) const
     nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
     return nCompact;
 }
+
+static void inline HashMix(uint32_t& a, uint32_t& b, uint32_t& c)
+{
+    // Taken from lookup3, by Bob Jenkins.
+    a -= c; a ^= ((c <<  4) | (c >> 28)); c += b;
+    b -= a; b ^= ((a <<  6) | (a >> 26)); a += c;
+    c -= b; c ^= ((b <<  8) | (b >> 24)); b += a;
+    a -= c; a ^= ((c << 16) | (c >> 16)); c += b;
+    b -= a; b ^= ((a << 19) | (a >> 13)); a += c;
+    c -= b; c ^= ((b <<  4) | (b >> 28)); b += a;
+}
+
+static void inline HashFinal(uint32_t& a, uint32_t& b, uint32_t& c)
+{
+    // Taken from lookup3, by Bob Jenkins.
+    c ^= b; c -= ((b << 14) | (b >> 18));
+    a ^= c; a -= ((c << 11) | (c >> 21));
+    b ^= a; b -= ((a << 25) | (a >>  7));
+    c ^= b; c -= ((b << 16) | (b >> 16));
+    a ^= c; a -= ((c <<  4) | (c >> 28));
+    b ^= a; b -= ((a << 14) | (a >> 18));
+    c ^= b; c -= ((b << 24) | (b >>  8));
+}
+
+uint64_t uint256::GetHash(const uint256 &salt) const
+{
+    uint32_t a, b, c;
+    a = b = c = 0xdeadbeef + (WIDTH << 2);
+
+    a += pn[0] ^ salt.pn[0];
+    b += pn[1] ^ salt.pn[1];
+    c += pn[2] ^ salt.pn[2];
+    HashMix(a, b, c);
+    a += pn[3] ^ salt.pn[3];
+    b += pn[4] ^ salt.pn[4];
+    c += pn[5] ^ salt.pn[5];
+    HashMix(a, b, c);
+    a += pn[6] ^ salt.pn[6];
+    b += pn[7] ^ salt.pn[7];
+    HashFinal(a, b, c);
+
+    return ((((uint64_t)b) << 32) | c);
+}