public override void DecodeBytes(string s, int startIndex, int length, Stream outputStream)
{
var abc = Alphabet;
var temp = new byte[8];
var bitGroup = new BitGroup(_bitCount);
while (length > _bitGroupCharCount)
{
// this is the faster code path
// it does not need to check for padding
// or rather it does not expect to encounter any padding
bitGroup.Reset();
for (int i = 0; i < _bitGroupCharCount; i++)
{
var c = s[startIndex + i];
var x = (uint)abc.Decode(c);
bitGroup.Write(x);
}
bitGroup.Read(temp, 0, _bitGroupByteCount);
outputStream.Write(temp, 0, _bitGroupByteCount);
startIndex += _bitGroupCharCount;
length -= _bitGroupCharCount;
}
// padding?
if (length > 0)
{
bitGroup.Reset();
int i, padding = 0;
for (i = 0; i < _bitGroupCharCount; i++)
{
var c = s[startIndex + i];
if (c == _paddingChar)
{
bitGroup.Write(0);
padding++;
continue;
}
var x = (uint)abc.Decode(c);
bitGroup.Write(x);
}
bitGroup.Read(temp, 0, _bitGroupByteCount);
var byteCount = _byteCountFromCharCount[i - padding];
if (byteCount == -1)
{
throw new InvalidOperationException("Padding is invalid.");
}
outputStream.Write(temp, 0, byteCount);
}
}
public void BitGroup_LoadFromTest()
{
var xs = new[] {
Tuple.Create(new byte[] { }, 0x00UL),
Tuple.Create(new byte[] { 0x01 }, 0x01UL),
Tuple.Create(new byte[] { 0x01, 0x02 }, 0x0102UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03 }, 0x010203UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04 }, 0x01020304UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05 }, 0x0102030405UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 }, 0x010203040506UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 }, 0x01020304050607UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 }, 0x0102030405060708UL),
};
foreach (var x in xs)
{
var bitGroup = new BitGroup();
bitGroup.LoadFrom(x.Item1, 0, x.Item1.Length);
Assert.AreEqual(x.Item2, bitGroup.Value);
}
}
public void BitGroup_ReadByteArrayTest()
{
var xs = new[] {
Tuple.Create(new byte[] { }, 0x00UL),
Tuple.Create(new byte[] { 0x01 }, 0x01UL),
Tuple.Create(new byte[] { 0x01, 0x02 }, 0x0102UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03 }, 0x010203UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04 }, 0x01020304UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05 }, 0x0102030405UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 }, 0x010203040506UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 }, 0x01020304050607UL),
Tuple.Create(new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 }, 0x0102030405060708UL),
};
foreach (var x in xs)
{
var bitGroup = new BitGroup();
bitGroup.LoadFrom(x.Item1, 0, x.Item1.Length);
var temp = new byte[x.Item1.Length];
bitGroup.Read(temp, 0, temp.Length);
CollectionAssert.AreEqual(x.Item1, temp);
}
}
