public int Encode(Int64Entry *src, int count, byte *dst)
{
if (count <= 0)
{
return(count);
}
var minDeltaTicks = long.MaxValue;
var maxNegDeltaValue = long.MinValue;
var minPosDeltaValue = long.MaxValue;
for (var i = 1; i < count; i++)
{
minDeltaTicks = Math.Min(minDeltaTicks, (src + i)->ticks - (src + i - 1)->ticks);
var delta = (src + i)->value - (src + i - 1)->value;
if (delta < 0)
{
maxNegDeltaValue = Math.Max(maxNegDeltaValue, delta);
}
else
{
minPosDeltaValue = Math.Min(minPosDeltaValue, delta);
}
}
var start = dst;
maxNegDeltaValue = -maxNegDeltaValue;
// Encodes header
Codec.EncodeInt64(src->ticks, ref dst);
Codec.EncodeInt64(minDeltaTicks, ref dst);
Codec.EncodeInt64(src->value, ref dst);
Codec.EncodeInt64(maxNegDeltaValue, ref dst);
Codec.EncodeInt64(minPosDeltaValue, ref dst);
// Encodes data block
for (var i = 1; i < count; i++)
{
Codec.EncodeInt64(((src + i)->ticks - (src + i - 1)->ticks) - minDeltaTicks, ref dst);
var delta = (src + i)->value - (src + i - 1)->value;
if (delta < 0)
{
Codec.EncodeInt64(true, -delta - maxNegDeltaValue, ref dst);
}
else
{
Codec.EncodeInt64(false, delta - minPosDeltaValue, ref dst);
}
}
return((int)(dst - start));
}
public int Decode(byte *src, int len, Int64Entry *dst)
{
if (len <= 0)
{
return(len);
}
var end = src + len;
// Decodes header
dst->ticks = Codec.DecodeInt64(ref src);
var minDeltaTicks = Codec.DecodeInt64(ref src);
dst->value = Codec.DecodeInt64(ref src);
var maxNegDeltaValue = Codec.DecodeInt64(ref src);
var minPosDeltaValue = Codec.DecodeInt64(ref src);
// Decodes data block
var start = dst;
dst++;
while (src < end)
{
dst->ticks = (dst - 1)->ticks + Codec.DecodeInt64(ref src) + minDeltaTicks;
var delta = Codec.DecodeInt64(ref src, out var isNegative);
if (isNegative)
{
dst->value = (dst - 1)->value - (delta + maxNegDeltaValue);
}
else
{
dst->value = (dst - 1)->value + delta + minPosDeltaValue;
}
dst++;
}
return((int)(dst - start));
}