From d26d07c9701748e54508107aa5c5580675c0e163 Mon Sep 17 00:00:00 2001
From: Maher Kassim <mkassim@cimpress.com>
Date: Sun, 4 Feb 2018 18:12:52 -0500
Subject: [PATCH] Added optimization for comparisons involving lowest- and
 highest-expanded postal codes

---
 src/PostalCodes/PostalCode.cs      | 97 +++++++++++++++++++++++++++++-
 src/PostalCodes/PostalCodeRange.cs |  2 +-
 2 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/src/PostalCodes/PostalCode.cs b/src/PostalCodes/PostalCode.cs
index f6d0512..a612d88 100644
--- a/src/PostalCodes/PostalCode.cs
+++ b/src/PostalCodes/PostalCode.cs
@@ -39,6 +39,34 @@ protected internal string PostalCodeString
             get { return _backingPostalCode; }
         }
 
+        /// <summary>
+        /// The lowest-expanded postal code (if the postal code is short)
+        /// </summary>
+        private readonly string _lowestExpandedPostalCode;
+
+        /// <summary>
+        /// Gets the lowest-expanded postal code string.
+        /// </summary>
+        /// <value>The lowest-expanded postal code string.</value>
+        protected internal string LowestExpandedPostalCodeString
+        {
+            get { return _lowestExpandedPostalCode; }
+        }
+
+        /// <summary>
+        /// The highest-expanded postal code (if the postal code is short)
+        /// </summary>
+        private readonly string _highestExpandedPostalCode;
+
+        /// <summary>
+        /// Gets the highest-expanded postal code string.
+        /// </summary>
+        /// <value>The highest-expanded postal code string.</value>
+        protected internal string HighestExpandedPostalCodeString
+        {
+            get { return _highestExpandedPostalCode; }
+        }
+
         /// <summary>
         /// The current format.
         /// </summary>
@@ -96,6 +124,9 @@ internal PostalCode(PostalCodeFormat[] formats, string redundantCharacters, stri
             }
 
             _backingPostalCode = String.Intern(Normalize(nonWhiteSpaceCode));
+
+            _lowestExpandedPostalCode = ExpandLowest();
+            _highestExpandedPostalCode = ExpandHighest();
         }
 
         /// <summary>
@@ -158,6 +189,16 @@ public virtual int CompareTo(PostalCode other)
             return other == null ? 1 : PostalCodeStringComparer.Default.Compare(PostalCodeString, other.PostalCodeString);
         }
 
+        /// <summary>
+        /// Compares the current object with another object of the same type.
+        /// </summary>
+        /// <param name="other">An object to compare with this object.</param>
+        /// <returns>A value that indicates the relative order of the objects being compared. The return value has the following meanings: Value Meaning Less than zero This object is less than the <paramref name="other" /> parameter.Zero This object is equal to <paramref name="other" />. Greater than zero This object is greater than <paramref name="other" />.</returns>
+        public virtual int CompareTo(string other)
+        {
+            return other == null ? 1 : PostalCodeStringComparer.Default.Compare(PostalCodeString, other);
+        }
+
         #endregion
 
         #region Implementation of IEquatable<PostalCode>
@@ -280,13 +321,43 @@ public int CompareTo(object obj)
             return left.CompareTo(right) <= 0;
         }
 
+        /// <summary>
+        /// Implements the &lt;=.
+        /// </summary>
+        /// <param name="left">The left (as postal code).</param>
+        /// <param name="right">The right (as string).</param>
+        /// <returns>The result of the operator.</returns>
+        public static bool operator <=(PostalCode left, string right)
+        {
+            if (left == null)
+            {
+                return true;
+            }
+            return left.CompareTo(right) <= 0;
+        }
+
+        /// <summary>
+        /// Implements the &gt;=.
+        /// </summary>
+        /// <param name="left">The left (as postal code).</param>
+        /// <param name="right">The right (as string).</param>
+        /// <returns>The result of the operator.</returns>
+        public static bool operator >=(PostalCode left, PostalCode right)
+        {
+            if (left == null)
+            {
+                return right == null;
+            }
+            return left.CompareTo(right) >= 0;
+        }
+
         /// <summary>
         /// Implements the &gt;=.
         /// </summary>
         /// <param name="left">The left.</param>
         /// <param name="right">The right.</param>
         /// <returns>The result of the operator.</returns>
-        public static bool operator >=(PostalCode left, PostalCode right)
+        public static bool operator >=(PostalCode left, string right)
         {
             if (left == null)
             {
@@ -324,6 +395,26 @@ public virtual string ToHumanReadableString()
             return ToHumanReadableString(outputFormat);
         }
 
+        private string ExpandLowest()
+        {
+            if (_currentFormatType == FormatType.Short && _currentFormat.ShortExpansionAsLowestInRange != null)
+            {
+                return _backingPostalCode + _currentFormat.ShortExpansionAsLowestInRange;
+            }
+
+            return _backingPostalCode;
+        }
+
+        private string ExpandHighest()
+        {
+            if (_currentFormatType == FormatType.Short && _currentFormat.ShortExpansionAsHighestInRange != null)
+            {
+                return _backingPostalCode + _currentFormat.ShortExpansionAsHighestInRange;
+            }
+
+            return _backingPostalCode;
+        }
+
         /// <summary>
         /// Expands the postal code as lowest in range.
         /// </summary>
@@ -342,7 +433,7 @@ public PostalCode ExpandPostalCodeAsLowestInRange()
                 }
             }
 
-            return CreatePostalCode(ToString(), _allowConvertToShort);
+            return this;
         }
 
         /// <summary>
@@ -363,7 +454,7 @@ public PostalCode ExpandPostalCodeAsHighestInRange()
                 }
             }
 
-            return CreatePostalCode(ToString(), _allowConvertToShort);
+            return this;
         }
 
         /// <summary>
diff --git a/src/PostalCodes/PostalCodeRange.cs b/src/PostalCodes/PostalCodeRange.cs
index ceb32f2..af5b1c3 100644
--- a/src/PostalCodes/PostalCodeRange.cs
+++ b/src/PostalCodes/PostalCodeRange.cs
@@ -359,7 +359,7 @@ public static bool Contains(PostalCodeRange range, PostalCode specificCode)
             }
 
             return range.IsDefault ||
-                   ((range.Start <= specificCode.ExpandPostalCodeAsLowestInRange()) && (specificCode.ExpandPostalCodeAsHighestInRange() <= range.End));
+                   ((range.Start <= specificCode.LowestExpandedPostalCodeString) && (range.End >= specificCode.HighestExpandedPostalCodeString));
         }
 
         /// <summary>