public void Generate(UInt32[] valsTable, UInt32 n)
{
UInt32 i;
// lengths: represents lengths of encoded values
var lengths = new UInt32[n];
this.n = n;
totalLength = 0;
for (i = 0; i < this.n; i++)
{
if (valsTable[i] == 0)
{
lengths[i] = 0;
}
else
{
lengths[i] = ILog2(valsTable[i] + 1);
totalLength += lengths[i];
}
}
storeTable = new UInt32[(totalLength + 31) >> 5];
totalLength = 0;
for (i = 0; i < this.n; i++)
{
if (valsTable[i] == 0)
{
continue;
}
var storedValue = valsTable[i] - ((1U << (Int32)lengths[i]) - 1U);
BitBool.SetBitsAtPos(storeTable, totalLength, storedValue, lengths[i]);
totalLength += lengths[i];
}
remR = ILog2(totalLength / this.n);
if (remR == 0)
{
remR = 1;
}
lengthRems = new UInt32[((this.n * remR) + 0x1f) >> 5];
var remsMask = (1U << (Int32)remR) - 1U;
totalLength = 0;
for (i = 0; i < this.n; i++)
{
totalLength += lengths[i];
BitBool.SetBitsValue(lengthRems, i, totalLength & remsMask, remR, remsMask);
lengths[i] = totalLength >> (Int32)remR;
}
sel = new Select();
sel.Generate(lengths, this.n, (totalLength >> (Int32)remR));
}
public UInt32 Query(UInt32 idx)
{
UInt32 selRes;
UInt32 encIdx;
var remsMask = (UInt32)((1 << (Int32)remR) - 1);
if (idx == 0)
{
encIdx = 0;
selRes = sel.Query(idx);
}
else
{
selRes = sel.Query(idx - 1);
encIdx = (selRes - (idx - 1)) << (Int32)remR;
encIdx += BitBool.GetBitsValue(lengthRems, idx - 1, remR, remsMask);
selRes = sel.NextQuery(selRes);
}
var encLength = (selRes - idx) << (Int32)remR;
encLength += BitBool.GetBitsValue(lengthRems, idx, remR, remsMask);
encLength -= encIdx;
if (encLength == 0)
{
return(0);
}
return(BitBool.GetBitsAtPos(storeTable, encIdx, encLength) + ((UInt32)((1 << (Int32)encLength) - 1)));
}
