From d290dbadadd9eb677db396fdfb3b34c9038638bb Mon Sep 17 00:00:00 2001
From: Lynne <lynne@bune.city>
Date: Wed, 14 Oct 2020 02:51:53 +1000
Subject: [PATCH] nicer way of parsing barcode 'fragments', bar to decimal
 table support

---
 .../.idea.auspostcode.dir/.idea/workspace.xml |  88 +++++++-------
 Barcode.cs                                    | 110 ++++++++++++++----
 BaseConversion.cs                             |   2 +-
 Program.cs                                    |   9 +-
 4 files changed, 139 insertions(+), 70 deletions(-)

diff --git a/.idea/.idea.auspostcode.dir/.idea/workspace.xml b/.idea/.idea.auspostcode.dir/.idea/workspace.xml
index e3bdc7c..610d25d 100644
--- a/.idea/.idea.auspostcode.dir/.idea/workspace.xml
+++ b/.idea/.idea.auspostcode.dir/.idea/workspace.xml
@@ -20,12 +20,9 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="373c5ee6-3f10-450b-8af6-fc4dd99290b0" name="Default Changelist" comment="initial commit, as they say">
-      <change afterPath="$PROJECT_DIR$/BaseConversion.cs" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.gitignore" beforeDir="false" afterPath="$PROJECT_DIR$/.gitignore" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.idea/.idea.auspostcode.dir/.idea/contentModel.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/.idea.auspostcode.dir/.idea/contentModel.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/.idea.auspostcode.dir/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/.idea.auspostcode.dir/.idea/workspace.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/Barcode.cs" beforeDir="false" afterPath="$PROJECT_DIR$/Barcode.cs" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/Folder.DotSettings.user" beforeDir="false" />
+      <change beforePath="$PROJECT_DIR$/BaseConversion.cs" beforeDir="false" afterPath="$PROJECT_DIR$/BaseConversion.cs" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/Program.cs" beforeDir="false" afterPath="$PROJECT_DIR$/Program.cs" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
@@ -40,6 +37,7 @@
     <setting file="file://$APPLICATION_CONFIG_DIR$/resharper-host/DecompilerCache/decompiler/87DBB896-6B20-4A14-9B6A-7AB43642646D/42/0e5622b9/Number.cs" root0="SKIP_HIGHLIGHTING" />
     <setting file="file://$APPLICATION_CONFIG_DIR$/resharper-host/DecompilerCache/decompiler/A5F6779E-8C83-415E-AF7A-DAB44F32C608/c6/1054d372/ThrowHelper.cs" root0="SKIP_HIGHLIGHTING" />
     <setting file="file://$APPLICATION_CONFIG_DIR$/resharper-host/DecompilerCache/decompiler/A5F6779E-8C83-415E-AF7A-DAB44F32C608/84/0eb89c24/Enumerable.cs" root0="SKIP_HIGHLIGHTING" />
+    <setting file="file://$APPLICATION_CONFIG_DIR$/resharper-host/DecompilerCache/decompiler/87DBB896-6B20-4A14-9B6A-7AB43642646D/88/6811f6df/String.cs" root0="SKIP_HIGHLIGHTING" />
   </component>
   <component name="IdeDocumentHistory">
     <option name="CHANGED_PATHS">
@@ -98,7 +96,7 @@
       <option name="number" value="Default" />
       <option name="presentableId" value="Default" />
       <updated>1602593942454</updated>
-      <workItem from="1602593947835" duration="11001000" />
+      <workItem from="1602593947835" duration="13843000" />
     </task>
     <task id="LOCAL-00001" summary="initial commit, as they say">
       <created>1602597326777</created>
@@ -150,86 +148,86 @@
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
     <state x="727" y="366" width="424" height="478" key="FileChooserDialogImpl/0.0.1920.1054@0.0.1920.1054" timestamp="1602597073977" />
-    <state width="1878" height="374" key="GridCell.Tab.0.bottom" timestamp="1602604911216">
+    <state width="1878" height="374" key="GridCell.Tab.0.bottom" timestamp="1602607646431">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.0.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911216" />
-    <state width="1878" height="374" key="GridCell.Tab.0.center" timestamp="1602604911213">
+    <state width="1878" height="374" key="GridCell.Tab.0.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646431" />
+    <state width="1878" height="374" key="GridCell.Tab.0.center" timestamp="1602607646431">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.0.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911213" />
-    <state width="1878" height="374" key="GridCell.Tab.0.left" timestamp="1602604911211">
+    <state width="1878" height="374" key="GridCell.Tab.0.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646431" />
+    <state width="1878" height="374" key="GridCell.Tab.0.left" timestamp="1602607646431">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.0.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911211" />
-    <state width="1878" height="374" key="GridCell.Tab.0.right" timestamp="1602604911214">
+    <state width="1878" height="374" key="GridCell.Tab.0.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646431" />
+    <state width="1878" height="374" key="GridCell.Tab.0.right" timestamp="1602607646431">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.0.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911214" />
-    <state width="1878" height="374" key="GridCell.Tab.1.bottom" timestamp="1602604911221">
+    <state width="1878" height="374" key="GridCell.Tab.0.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646431" />
+    <state width="1878" height="374" key="GridCell.Tab.1.bottom" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.1.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911221" />
-    <state width="1878" height="374" key="GridCell.Tab.1.center" timestamp="1602604911218">
+    <state width="1878" height="374" key="GridCell.Tab.1.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.1.center" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.1.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911218" />
-    <state width="1878" height="374" key="GridCell.Tab.1.left" timestamp="1602604911217">
+    <state width="1878" height="374" key="GridCell.Tab.1.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.1.left" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.1.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911217" />
-    <state width="1878" height="374" key="GridCell.Tab.1.right" timestamp="1602604911220">
+    <state width="1878" height="374" key="GridCell.Tab.1.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.1.right" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.1.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911220" />
-    <state width="1878" height="374" key="GridCell.Tab.2.bottom" timestamp="1602604911227">
+    <state width="1878" height="374" key="GridCell.Tab.1.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.2.bottom" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.2.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911227" />
-    <state width="1878" height="374" key="GridCell.Tab.2.center" timestamp="1602604911224">
+    <state width="1878" height="374" key="GridCell.Tab.2.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.2.center" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.2.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911224" />
-    <state width="1878" height="374" key="GridCell.Tab.2.left" timestamp="1602604911223">
+    <state width="1878" height="374" key="GridCell.Tab.2.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.2.left" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.2.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911223" />
-    <state width="1878" height="374" key="GridCell.Tab.2.right" timestamp="1602604911225">
+    <state width="1878" height="374" key="GridCell.Tab.2.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.2.right" timestamp="1602607646287">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.2.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911225" />
-    <state width="1878" height="374" key="GridCell.Tab.3.bottom" timestamp="1602604911232">
+    <state width="1878" height="374" key="GridCell.Tab.2.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646287" />
+    <state width="1878" height="374" key="GridCell.Tab.3.bottom" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.3.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911232" />
-    <state width="1878" height="374" key="GridCell.Tab.3.center" timestamp="1602604911230">
+    <state width="1878" height="374" key="GridCell.Tab.3.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.3.center" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.3.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911230" />
-    <state width="1878" height="374" key="GridCell.Tab.3.left" timestamp="1602604911229">
+    <state width="1878" height="374" key="GridCell.Tab.3.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.3.left" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.3.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911229" />
-    <state width="1878" height="374" key="GridCell.Tab.3.right" timestamp="1602604911231">
+    <state width="1878" height="374" key="GridCell.Tab.3.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.3.right" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.3.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911231" />
-    <state width="1878" height="374" key="GridCell.Tab.4.bottom" timestamp="1602604911236">
+    <state width="1878" height="374" key="GridCell.Tab.3.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.4.bottom" timestamp="1602607646289">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.4.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911236" />
-    <state width="1878" height="374" key="GridCell.Tab.4.center" timestamp="1602604911234">
+    <state width="1878" height="374" key="GridCell.Tab.4.bottom/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646289" />
+    <state width="1878" height="374" key="GridCell.Tab.4.center" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.4.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911234" />
-    <state width="1878" height="374" key="GridCell.Tab.4.left" timestamp="1602604911233">
+    <state width="1878" height="374" key="GridCell.Tab.4.center/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.4.left" timestamp="1602607646288">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.4.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911233" />
-    <state width="1878" height="374" key="GridCell.Tab.4.right" timestamp="1602604911235">
+    <state width="1878" height="374" key="GridCell.Tab.4.left/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646288" />
+    <state width="1878" height="374" key="GridCell.Tab.4.right" timestamp="1602607646289">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
-    <state width="1878" height="374" key="GridCell.Tab.4.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602604911235" />
+    <state width="1878" height="374" key="GridCell.Tab.4.right/0.0.1920.1054@0.0.1920.1054" timestamp="1602607646289" />
     <state x="738" y="92" key="SettingsEditor" timestamp="1602603890848">
       <screen x="0" y="0" width="1920" height="1054" />
     </state>
diff --git a/Barcode.cs b/Barcode.cs
index 57f0d87..f3d65e7 100644
--- a/Barcode.cs
+++ b/Barcode.cs
@@ -5,14 +5,27 @@ using System.Text.RegularExpressions;
 
 namespace AusPostCode {
 	public class Barcode {
-		public enum BarcodeFragment {
-			FormatControlCode,
-			SortingCode,
-			CustomerInformation,
-			ErrorCorrection,
+		private readonly struct BarcodeFragment {
+			public EncodingFormat TypicalFormat { get; }
+			public int Length { get;}
+			public int Offset { get; }
+
+			public BarcodeFragment(EncodingFormat typicalFormat, int length, int offset) {
+				TypicalFormat = typicalFormat;
+				Length = length;
+				Offset = offset;
+			}
 		}
 
-		public enum EncodingFormat {
+		private readonly Dictionary<string, BarcodeFragment> _fragments = new Dictionary<string, BarcodeFragment> {
+			["FormatControlCode"] = new BarcodeFragment(EncodingFormat.N, 4, 2),
+			["SortingCode"] = new BarcodeFragment(EncodingFormat.N, 16, 6),
+			["CustomerInformation2"] = new BarcodeFragment(EncodingFormat.C, 16, 22),
+			["CustomerInformation3"] = new BarcodeFragment(EncodingFormat.C, 31, 22),
+			["ErrorCorrection"] = new BarcodeFragment(EncodingFormat.BarToDecimal, 12, - 16),
+		};
+
+		private enum EncodingFormat {
 			N,
 			C,
 			BarToDecimal,
@@ -20,7 +33,7 @@ namespace AusPostCode {
 
 		private int _formatCode;
 
-		public Dictionary<int, string> FormatTable = new Dictionary<int, string> {
+		private readonly Dictionary<int, string> _formatTable = new Dictionary<int, string> {
 			[0] = "Null Customer Barcode",
 			[11] = "Standard Customer Barcode",
 			[52] = "Customer Business Reply Paid",
@@ -45,31 +58,82 @@ namespace AusPostCode {
 			}
 
 			// process Format Control Code
-			_formatCode = int.Parse(Decode(GetFragment(BarcodeFragment.FormatControlCode), EncodingFormat.N));
+			_formatCode = int.Parse(GetFragment(_fragments["FormatControlCode"]));
 			Console.WriteLine(Format);
 
 			// process Sorting Code Field
-			SortingCode = int.Parse(Decode(GetFragment(BarcodeFragment.SortingCode), EncodingFormat.N));
+			SortingCode = int.Parse(GetFragment(_fragments["SortingCode"]));
 			Console.WriteLine($"Sorting code: {SortingCode}");
+
+			// process Customer Information, if necessary
+			// TODO: actually do this, and get a code to test it on. also, ensure that customer codes are the right length
+			if (_formatCode == 59) {
+				Console.WriteLine("This code has a Customer Information field, but I don't know how to process that yet 0uo");
+			} else if (_formatCode == 62) {
+				Console.WriteLine("This code has a Customer Information field, but I don't know how to process that yet 0uo");
+			}
+
+			// process Reed-Solomon Error Correction Bars
+			// TODO: actually validate the barcode
+			Console.WriteLine(BaseConversion.FromBase(GetFragment(_fragments["ErrorCorrection"]), 64));
+
 		}
 
 		public int SortingCode { get; set; }
 		public int CustomerInformation { get; set; }
-		public string Format => FormatTable.ContainsKey(_formatCode) ? FormatTable[_formatCode] : $"Unknown ({_formatCode})";
-		private List<string> Warnings { get; set; } = new List<string>();
-		private string Code { get; set; }
+		public string Format => _formatTable.ContainsKey(_formatCode) ? _formatTable[_formatCode] : $"Unknown ({_formatCode})";
+		private List<string> Warnings { get; } = new List<string>();
+		private string Code { get; }
 
-		private string GetFragment(BarcodeFragment barcodeFragment) {
-			return barcodeFragment switch {
-				BarcodeFragment.FormatControlCode => Code.Substring(2, 4),
-				BarcodeFragment.SortingCode => Code.Substring(6, 16),
-				BarcodeFragment.CustomerInformation when _formatCode == 59 => Code.Substring(22, 16),
-				BarcodeFragment.CustomerInformation when _formatCode == 62 => Code.Substring(22, 31),
-				BarcodeFragment.CustomerInformation => null, // format doesn't support the customer information field
-				BarcodeFragment.ErrorCorrection => Code.Substring(Code.Length - 15,
-					12), // the error correction bars are always immediately before the stop bars
-				_ => throw new ArgumentOutOfRangeException(nameof(barcodeFragment), barcodeFragment, null),
-			};
+		private string GetFragment(BarcodeFragment fragment, bool decode = true) {
+			var data = Code.Substring(fragment.Offset < 0 ? Code.Length + fragment.Offset : fragment.Offset, fragment.Length);
+
+			if (!decode) {
+				return data;
+			}
+
+			// bool badData;
+			var chunkLength = fragment.TypicalFormat == EncodingFormat.N ? 2 : 3;
+			var rx = new Regex("^[0123]+$");
+			var sb = new StringBuilder();
+			if (!rx.IsMatch(data)) {
+				throw new ArgumentException("Input length must be a quaternary number.", nameof(data));
+			}
+
+			for (var i = 0; i < data.Length; i += chunkLength) {
+				var chunk = data.Substring(i, chunkLength);
+
+				switch (fragment.TypicalFormat) {
+					case EncodingFormat.N:
+						// format N supports the digits 0 through 9, and nothing else.
+						// digits 0 through 8 are stored as their ternary representations, while 9 is stored as "30".
+
+						if (chunk == "30") {
+							sb.Append(9);
+						}
+						else if (chunk.Contains("3")) {
+							// not a ternary number
+							throw new ArgumentException($"{chunk} is not a valid identifier for format {data.ToString()}.");
+						}
+						else {
+							sb.Append(BaseConversion.FromBase(chunk, 3));
+						}
+						break;
+
+					case EncodingFormat.C:
+						break;
+
+					case EncodingFormat.BarToDecimal:
+						var digitInt = BaseConversion.FromBase(chunk, 4);
+						sb.Insert(0, BaseConversion.ToBase(digitInt, 64));
+						break;
+
+					default:
+						throw new ArgumentOutOfRangeException(nameof(fragment.TypicalFormat), fragment.TypicalFormat, null);
+				}
+			}
+
+			return sb.ToString();
 		}
 
 		private static string Decode(string input, EncodingFormat format) {
diff --git a/BaseConversion.cs b/BaseConversion.cs
index bb2dbf9..3c49a84 100644
--- a/BaseConversion.cs
+++ b/BaseConversion.cs
@@ -6,7 +6,7 @@ namespace AusPostCode {
 	public static class BaseConversion {
 		// honestly surprised c# doesn't do this out of the box
 
-		private static readonly char[] Characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
+		private static readonly char[] Characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-=".ToCharArray();
 
 		// thanks to https://stackoverflow.com/a/35004409
 		private static readonly Dictionary<char, int> CharacterIndices =
diff --git a/Program.cs b/Program.cs
index 1da76be..83835fa 100644
--- a/Program.cs
+++ b/Program.cs
@@ -22,8 +22,15 @@ using CommandLine;
 namespace AusPostCode {
 	internal class Program {
 		private static void Main(string[] args) {
-			Console.WriteLine("Hello World!");
+			// test code consisting of the following:
+			// - start bars
+			// - fcc of 0101 == 11 == standard customer barcode
+			// - sorting code of 2112011202120020 == 75152506
+			// - a filler bar of 3
+			// - a reed-solomon code of 001101103221 == 10826817
+			// - end bars
 			const string testCode = "1301012112011202120020300110110322113";
+
 			var barcode = new Barcode(testCode);
 		}