/// <summary>
/// Find the length of the sequence of bytes that are equal from array a, starring at index index,
/// and array b, starting at 0.
/// </summary>
/// <param name="a"> Larger array to look at from index. </param>
/// <param name="index"> Index in a to look for match. </param>
/// <param name="b"> Smaller array to match in a at index. </param>
/// <returns></returns>
public static int MatchingBytesCount(ByteArrayIndexer a, int index, ByteArrayIndexer b)
{
var i = 0;
for (; i < b.Length && index + i < a.Length; ++i)
{
if (a[index + i] != b[i])
{
return(i);
}
}
return(i);
}
/// <summary>
/// This method finds the longest match of the needle in the haystack.
/// </summary>
/// <param name="haystack"> Large array to search in. </param>
/// <param name="needle"> Needle to search after. </param>
/// <returns> A MatchPointer describing the index of the needle and the length of the match. </returns>
public static MatchPointer FindLongestMatch(ByteArrayIndexer haystack, ByteArrayIndexer needle)
{
var longestMatch = 1;
var indexOfLongestMatch = 0;
//Find the longest match in the haystack
for (var i = 0; i < haystack.Length - longestMatch; ++i)
{
var matchedBytes = MatchingBytesCount(haystack, i, needle);
if (matchedBytes > longestMatch)
{
longestMatch = matchedBytes;
indexOfLongestMatch = i;
}
}
return(longestMatch > 1 ? new MatchPointer(indexOfLongestMatch, longestMatch) : default(MatchPointer));
}
public static extern MatchPointer FindLongestMatch(ByteArrayIndexer haystack, ByteArrayIndexer needle);