// Method added by Sonic-The-Hedgehog-LNK1123 (github.com/Sonic-The-Hedgehog-LNK1123)
private GenericGFPoly findErrataLocator(int[] errorPositions)
{
GenericGFPoly errataLocator = new GenericGFPoly(field, new int[] { 1 }, false);
foreach (int i in errorPositions)
{
errataLocator = errataLocator.multiply(new GenericGFPoly(field, new int[] { 1 }, false).addOrSubtract(new GenericGFPoly(field, new int[] { field.exp(i), 0 }, false)));
}
return(errataLocator);
}
// Method added by Sonic-The-Hedgehog-LNK1123 (github.com/Sonic-The-Hedgehog-LNK1123)
// this method replaces original method "runEuclideanAlgorithm"
internal GenericGFPoly runBerlekampMasseyAlgorithm(GenericGFPoly syndrome, int erasureCount)
{
GenericGFPoly sigma = new GenericGFPoly(field, new int[] { 1 }, false);
GenericGFPoly old = new GenericGFPoly(field, new int[] { 1 }, false);
for (int i = 0; i < (syndrome.Coefficients.Length - erasureCount); i++)
{
int delta = syndrome.getCoefficient(i);
for (int j = 1; j < sigma.Coefficients.Length; j++)
{
delta ^= field.multiply(sigma.getCoefficient(j), syndrome.getCoefficient(i - j));
}
List <int> oldList = new List <int>(old.Coefficients);
oldList.Add(0);
old = new GenericGFPoly(field, oldList.ToArray(), false);
if (delta != 0)
{
if (old.Coefficients.Length > sigma.Coefficients.Length)
{
GenericGFPoly new_loc = old.multiply(delta);
old = sigma.multiply(field.inverse(delta));
sigma = new_loc;
}
sigma = sigma.addOrSubtract(old.multiply(delta));
}
}
List <int> sigmaList = new List <int>(sigma.Coefficients);
while (Convert.ToBoolean(sigmaList.Count) && sigmaList[0] == 0)
{
sigmaList.RemoveAt(0);
}
sigma = new GenericGFPoly(field, sigmaList.ToArray(), false);
return(sigma);
}
// Method added by Sonic-The-Hedgehog-LNK1123 (github.com/Sonic-The-Hedgehog-LNK1123)
private GenericGFPoly?findErrorEvaluator(GenericGFPoly syndrome, GenericGFPoly errataLocations)
{
int[] product = syndrome.multiply(errataLocations).Coefficients;
int[] target = new int[errataLocations.Coefficients.Length - 1];
Array.Copy(product, product.Length - errataLocations.Coefficients.Length + 1, target, 0, target.Length);
if (target.Length == 0)
{
return(null);
}
GenericGFPoly omega = new GenericGFPoly(field, target, false);
return(omega);
}
