From 8ea8086b1a249a9272b10182091d01d443107c3d Mon Sep 17 00:00:00 2001
From: Rune Nielsen <runenielsen@runbox.com>
Date: Thu, 13 Jan 2022 09:53:17 +0100
Subject: [PATCH] now correclty converts to padded 10 bytes from BigInteger
 (#46)

---
 src/MsSqlCdc/Cdc.cs         | 14 +++++++-------
 src/MsSqlCdc/DataConvert.cs | 12 ++++++++++--
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/MsSqlCdc/Cdc.cs b/src/MsSqlCdc/Cdc.cs
index 4392bc6..956dec9 100644
--- a/src/MsSqlCdc/Cdc.cs
+++ b/src/MsSqlCdc/Cdc.cs
@@ -185,7 +185,7 @@ public static async Task<BigInteger> MapTimeToLsn(
     /// </returns>
     public static async Task<DateTime> MapLsnToTime(SqlConnection connection, BigInteger lsn)
     {
-        var binaryLsn = DataConvert.ConvertLsnBigEridian(lsn);
+        var binaryLsn = DataConvert.ConvertLsnBigEndian(lsn);
         var lsnToTime = await CdcDatabase.MapLsnToTime(connection, binaryLsn);
         if (!lsnToTime.HasValue)
             throw new Exception($"Could not convert LSN to time with LSN being '{lsn}'");
@@ -233,7 +233,7 @@ public static async Task<BigInteger> GetMaxLsn(SqlConnection connection)
     /// <returns>Return the high endpoint of the change data capture timeline for any capture instance.</returns>
     public static async Task<BigInteger> GetPreviousLsn(SqlConnection connection, BigInteger lsn)
     {
-        var binaryLsn = DataConvert.ConvertLsnBigEridian(lsn);
+        var binaryLsn = DataConvert.ConvertLsnBigEndian(lsn);
         var previousLsnBytes = await CdcDatabase.DecrementLsn(connection, binaryLsn);
         if (previousLsnBytes is null)
             throw new Exception($"Could not get previous lsn on {nameof(lsn)}: '{lsn}'.");
@@ -249,7 +249,7 @@ public static async Task<BigInteger> GetPreviousLsn(SqlConnection connection, Bi
     /// <returns>Get the next log sequence number (LSN) in the sequence based upon the specified LSN.</returns>
     public static async Task<BigInteger> GetNextLsn(SqlConnection connection, BigInteger lsn)
     {
-        var lsnBinary = DataConvert.ConvertLsnBigEridian(lsn);
+        var lsnBinary = DataConvert.ConvertLsnBigEndian(lsn);
         var nextLsnBytes = await CdcDatabase.IncrementLsn(connection, lsnBinary);
         if (nextLsnBytes is null)
             throw new Exception($"Could not get next lsn on {nameof(lsn)}: '{lsn}'.");
@@ -274,8 +274,8 @@ public static async Task<IReadOnlyCollection<ChangeRow<dynamic>>> GetNetChanges(
         BigInteger toLsn,
         NetChangesRowFilterOption netChangesRowFilterOption = NetChangesRowFilterOption.All)
     {
-        var beginLsnBinary = DataConvert.ConvertLsnBigEridian(fromLsn);
-        var endLsnBinary = DataConvert.ConvertLsnBigEridian(toLsn);
+        var beginLsnBinary = DataConvert.ConvertLsnBigEndian(fromLsn);
+        var endLsnBinary = DataConvert.ConvertLsnBigEndian(toLsn);
         var filterOption = DataConvert.ConvertNetChangesRowFilterOption(netChangesRowFilterOption);
         var cdcColumns = await CdcDatabase.GetNetChanges(
             connection, captureInstance, beginLsnBinary, endLsnBinary, filterOption);
@@ -301,8 +301,8 @@ public static async Task<IReadOnlyCollection<ChangeRow<dynamic>>> GetAllChanges(
         BigInteger endLsn,
         AllChangesRowFilterOption allChangesRowFilterOption = AllChangesRowFilterOption.All)
     {
-        var beginLsnBinary = DataConvert.ConvertLsnBigEridian(beginLsn);
-        var endLsnBinary = DataConvert.ConvertLsnBigEridian(endLsn);
+        var beginLsnBinary = DataConvert.ConvertLsnBigEndian(beginLsn);
+        var endLsnBinary = DataConvert.ConvertLsnBigEndian(endLsn);
         var filterOption = DataConvert.ConvertAllChangesRowFilterOption(allChangesRowFilterOption);
         var cdcColumns = await CdcDatabase.GetAllChanges(
             connection, captureInstance, beginLsnBinary, endLsnBinary, filterOption);
diff --git a/src/MsSqlCdc/DataConvert.cs b/src/MsSqlCdc/DataConvert.cs
index 9634947..8e2baa4 100644
--- a/src/MsSqlCdc/DataConvert.cs
+++ b/src/MsSqlCdc/DataConvert.cs
@@ -115,11 +115,19 @@ public static string ConvertAllChangesRowFilterOption(
         };
 
     /// <summary>
-    /// Convert LSN BigInteger to ByteArray in BigEndian format.
+    /// Convert LSN BigInteger to ByteArray in BigEndian format,
+    /// Also makes sure that the size of the returned byte array is always 10 bytes.
     /// </summary>
     /// <param name="representation">BigInteger representation of LSN.</param>
     /// <returns>Binary array of BigInteger LSN.</returns>
-    public static byte[] ConvertLsnBigEridian(BigInteger lsn) => lsn.ToByteArray().Reverse().ToArray();
+    public static byte[] ConvertLsnBigEndian(BigInteger lsn)
+    {
+        var newArray = new byte[10];
+        var lsnBytes = lsn.ToByteArray(isBigEndian: true);
+        var startAt = newArray.Length - lsnBytes.Length;
+        Array.Copy(lsnBytes, 0, newArray, startAt, lsnBytes.Length);
+        return newArray;
+    }
 
     /// <summary>
     /// Convert the binary representation of the line-sequence-number to BigInteger.