Replace usage of remaining boost::unordered containers with std

Replace LLUUID and LLMaterialID container hashing functions with more collision resistant versions
Utilize boost::hash_combine for TEMaterialPair to generate good hash distribution
Generalize is_in_map and get_if_there for usage with all mapped types

1 files changed, 19 insertions, 11 deletions

diff --git a/indra/llprimitive/llmaterialid.h b/indra/llprimitive/llmaterialid.h
index bd6256d961..41dd5a8710 100644
--- a/indra/llprimitive/llmaterialid.h
+++ b/indra/llprimitive/llmaterialid.h
@@ -67,15 +67,11 @@ public:
 
     static const LLMaterialID null;
 
-    // Returns a 64 bits digest of the material Id, by XORing its two 64 bits
-    // long words. HB
-    inline U64 getDigest64() const
-    {
-        U64* tmp = (U64*)mID;
-        return tmp[0] ^ tmp[1];
-    }
-
 private:
+    // definitions follow class
+    friend std::hash<LLMaterialID>;
+    friend size_t hash_value(const LLMaterialID&) noexcept;
+
     void parseFromBinary(const LLSD::Binary& pMaterialID);
     void copyFromOtherMaterialID(const LLMaterialID& pOtherMaterialID);
     int  compareToOtherMaterialID(const LLMaterialID& pOtherMaterialID) const;
@@ -90,15 +86,27 @@ namespace std
     {
         inline size_t operator()(const LLMaterialID& id) const noexcept
         {
-            return (size_t)id.getDigest64();
+            size_t h = 0;
+            // Golden ratio hash with avalanche mixing
+            // Process 8 bytes at a time by manually constructing 64-bit values
+            // Shift by 31: mixes upper half into lower half for better bit distribution
+            // Shift by 47: ensures highest bits influence final hash output
+            for (int i = 0; i < MATERIAL_ID_SIZE; i += 8) {
+                size_t chunk = (size_t)id.mID[i] | ((size_t)id.mID[i + 1] << 8) |
+                               ((size_t)id.mID[i+2] << 16) | ((size_t)id.mID[i+3] << 24) |
+                               ((size_t)id.mID[i+4] << 32) | ((size_t)id.mID[i+5] << 40) |
+                               ((size_t)id.mID[i + 6] << 48) | ((size_t)id.mID[i + 7] << 56);
+                h ^= (chunk * 0x9e3779b97f4a7c15ULL) ^ (h >> 31) ^ (h >> 47);
+            }
+            return h;
         }
     };
 }
 
-// For use with boost containers.
+// For use with boost::container_hash
 inline size_t hash_value(const LLMaterialID& id) noexcept
 {
-    return (size_t)id.getDigest64();
+    return std::hash<LLMaterialID>{}(id);
 }
 
 #endif // LL_LLMATERIALID_H