private static void EncodeSymbol(PpmModel model, int[] history, int symbol, ArithmeticEncoder enc)
{
var order = history.Length;
while (order >= 0)
{
var isBreak = false;
var ctx = model.RootContext;
for (var i = 0; i < order; i++)
{
ctx = ctx.Subcontexts[history[i]];
if (ctx == null)
{
order--;
isBreak = true;
break;
}
}
if (isBreak)
{
continue;
}
if (symbol != EscapeSymbol && ctx.Frequencies.Get(symbol) > 0)
{
enc.Write(ctx.Frequencies, symbol);
return;
}
enc.Write(ctx.Frequencies, EscapeSymbol);
order--;
}
enc.Write(model.orderMinus1Freqs, symbol);
}