public void TestEncodeDecodeInt32()
{
var values = new int[32 * 4];
for (var i = 1; i < 32; i++)
{
var value = (uint)Math.Pow(2, i);
values[i * 4] = (int)value - 1;
values[i * 4 + 1] = (int)value;
values[i * 4 + 2] = -values[i * 4];
values[i * 4 + 3] = -values[i * 4 + 1];
}
var buffer = stackalloc byte[5];
for (var i = 0; i < values.Length; i++)
{
var p = buffer;
Codec.EncodeInt32(values[i], ref p);
p = buffer;
var value = Codec.DecodeInt32(ref p);
Assert.AreEqual(values[i], value, "At idx: " + i);
}
}
public static void EncodeMinDelta32(byte *src, int len, int skip, ref byte *dst)
{
var start = src;
var end = src + len;
var next = sizeof(int) + skip;
var maxNegDelta = int.MinValue;
var minPosDelta = int.MaxValue;
src += next;
while (src < end)
{
var delta = *(int *)src - *(int *)(src - next);
if (delta < 0)
{
maxNegDelta = Math.Max(maxNegDelta, delta);
}
else
{
minPosDelta = Math.Min(minPosDelta, delta);
}
src += next;
}
src = start;
start = dst;
maxNegDelta = -maxNegDelta;
dst += sizeof(int);
Codec.EncodeInt32(*(int *)src, ref dst);
Codec.EncodeInt32(maxNegDelta, ref dst);
Codec.EncodeInt32(minPosDelta, ref dst);
src += next;
while (src < end)
{
var delta = *(int *)src - *(int *)(src - next);
if (delta < 0)
{
Codec.EncodeInt32(true, -delta - maxNegDelta, ref dst);
}
else
{
Codec.EncodeInt32(false, delta - minPosDelta, ref dst);
}
src += next;
}
*(int *)start = (int)(dst - start);
}
public int Encode(ref byte *src, int lSrc, ref byte *dst, int lDst)
{
var data = (Int32Entry *)src;
var count = lSrc / sizeof(Int32Entry) * sizeof(Int32Entry);
var minTicks = long.MaxValue;
var maxNegValue = int.MinValue;
var minPosValue = int.MaxValue;
for (var i = 0; i < count; i++)
{
minTicks = Math.Min(minTicks, (data + i)->ticks);
if ((data + i)->value < 0)
{
maxNegValue = Math.Max(maxNegValue, (data + i)->value);
}
else
{
minPosValue = Math.Min(minPosValue, (data + i)->value);
}
}
maxNegValue = -maxNegValue;
var start = dst;
// Encode header
Codec.EncodeInt64(minTicks, ref dst);
Codec.EncodeInt32(maxNegValue, ref dst);
Codec.EncodeInt32(minPosValue, ref dst);
for (var i = 0; i < count; i++)
{
Codec.EncodeInt64((data + i)->ticks - minTicks, ref dst);
if ((data + i)->value < 0)
{
Codec.EncodeInt32(true, -(data + i)->value - maxNegValue, ref dst);
}
else
{
Codec.EncodeInt32(false, (data + i)->value - minPosValue, ref dst);
}
}
return((int)(dst - start));
}