Introduce IdentifierManager to improve PDT evaluator performance.

Assets/Cryville/Common/Pdt/PdtOperator.cs

@@ -74,4 +74,48 @@ namespace Cryville.Common.Pdt {
 			return _etor.StackAlloc(type, _prmem, len);
 		}
 	}
+	/// <summary>
+	/// The signature of a <see cref="PdtOperator" />.
+	/// </summary>
+	public struct PdtOperatorSignature : IEquatable<PdtOperatorSignature> {
+		/// <summary>
+		/// The name of the operator.
+		/// </summary>
+		public int Name { get; private set; }
+		/// <summary>
+		/// The parameter count.
+		/// </summary>
+		public int ParamCount { get; private set; }
+		readonly int _hash;
+		/// <summary>
+		/// Creates an operator signature.
+		/// </summary>
+		/// <param name="name">The name of the operator.</param>
+		/// <param name="paramCount">The parameter count.</param>
+		public PdtOperatorSignature(string name, int paramCount)
+			: this(IdentifierManager.SharedInstance.Request(name), paramCount) { }
+		/// <summary>
+		/// Creates an operator signature.
+		/// </summary>
+		/// <param name="name">The identifier of the operator.</param>
+		/// <param name="paramCount">The parameter count.</param>
+		public PdtOperatorSignature(int name, int paramCount) {
+			Name = name;
+			ParamCount = paramCount;
+			_hash = Name ^ ((ParamCount << 16) | (ParamCount >> 16));
+		}
+		public override bool Equals(object obj) {
+			if (!(obj is PdtOperatorSignature)) return false;
+			return Equals((PdtOperatorSignature)obj);
+		}
+		public bool Equals(PdtOperatorSignature other) {
+			return Name == other.Name && ParamCount == other.ParamCount;
+		}
+		public override int GetHashCode() {
+			return _hash;
+		}
+		public override string ToString() {
+			return string.Format("{0}({1})", Name, ParamCount);
+		}
+	}
 }