// Does segment1 contain all of matchBytes, or does it end with the start of matchBytes?
// 1: AAAAABBBBBCCCCC
// 2: BBBBB
// Or:
// 1: AAAAABBB
// 2: BBBBB
private bool SubMatch(ArraySegment <byte> segment1, byte[] matchBytes, out int matchOffset, out int matchCount)
{
// clear matchCount to zero
matchCount = 0;
// case 1: does segment1 fully contain matchBytes?
{
var matchBytesLengthMinusOne = matchBytes.Length - 1;
var matchBytesLastByte = matchBytes[matchBytesLengthMinusOne];
var segmentEndMinusMatchBytesLength = segment1.Offset + segment1.Count - matchBytes.Length;
matchOffset = segment1.Offset;
while (matchOffset < segmentEndMinusMatchBytesLength)
{
var lookaheadTailChar = segment1.Array[matchOffset + matchBytesLengthMinusOne];
if (lookaheadTailChar == matchBytesLastByte &&
CompareBuffers(segment1.Array, matchOffset, matchBytes, 0, matchBytesLengthMinusOne) == 0)
{
matchCount = matchBytes.Length;
return(true);
}
matchOffset += _boundary.GetSkipValue(lookaheadTailChar);
}
}
// case 2: does segment1 end with the start of matchBytes?
var segmentEnd = segment1.Offset + segment1.Count;
matchCount = 0;
for (; matchOffset < segmentEnd; matchOffset++)
{
var countLimit = segmentEnd - matchOffset;
for (matchCount = 0; matchCount < matchBytes.Length && matchCount < countLimit; matchCount++)
{
if (matchBytes[matchCount] != segment1.Array[matchOffset + matchCount])
{
matchCount = 0;
break;
}
}
if (matchCount > 0)
{
break;
}
}
return(matchCount > 0);
}
