move tokens to new project

src/UglyToad.PdfPig.Core/IndirectReference.cs

@@ -0,0 +1,63 @@
+namespace UglyToad.PdfPig.Core
+{
+    using System.Diagnostics;
+
+    /// <summary>
+    /// Used to uniquely identify and refer to objects in the PDF file.
+    /// </summary>
+    public struct IndirectReference
+    {
+        /// <summary>
+        /// A positive integer object number.
+        /// </summary>
+        public long ObjectNumber { get; }
+
+        /// <summary>
+        /// A non-negative integer generation number which starts as 0 and increases if the file is updated incrementally.
+        /// </summary>
+        public int Generation { get; }
+
+        /// <summary>
+        /// Create a new <see cref="IndirectReference"/>
+        /// </summary>
+        /// <param name="objectNumber">The object number.</param>
+        /// <param name="generation">The generation number.</param>
+        [DebuggerStepThrough]
+        public IndirectReference(long objectNumber, int generation)
+        {
+            ObjectNumber = objectNumber;
+            Generation = generation;
+        }
+
+        /// <inheritdoc />
+        public override bool Equals(object obj)
+        {
+            if (obj is IndirectReference reference)
+            {
+                return reference.ObjectNumber == ObjectNumber
+                       && reference.Generation == Generation;
+            }
+
+            return false;
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                int hash = 59;
+                hash = hash * 97 + ObjectNumber.GetHashCode();
+                hash = hash * 97 + Generation.GetHashCode();
+
+                return hash;
+            }
+        }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return $"{ObjectNumber} {Generation}";
+        }
+    }
+}