public bool Decode(int[] received, int ecBytes)
{
if (ecBytes == 0)
{
throw new ArgumentException("No error correction bytes");
}
var dataBytes = received.Length - ecBytes;
if (dataBytes <= 0)
{
throw new ArgumentException("No data bytes provided");
}
var errorsCorrected = false;
var generator = BuildGenerator(ecBytes);
var count = 0;
GenericGFPoly remainder = null;
var iteratorTemp = new int[received.Length];
Array.Copy(received, iteratorTemp, received.Length);
var tempInfo = new GenericGFPoly(_field, iteratorTemp);
while (count <= dataBytes)
{
remainder = tempInfo.divide(generator)[1];
if (remainder.Coefficients.Count(coeff => coeff != 0) <= ecBytes / 2)
{
errorsCorrected = true;
break;
}
count++;
Array.Copy(received, 0, iteratorTemp, count, received.Length - count);
Array.Copy(received, received.Length - count, iteratorTemp, 0, count);
tempInfo = new GenericGFPoly(_field, iteratorTemp);
}
if (!errorsCorrected)
{
return false;
}
if (count == 0)
{
return true;
}
var correctedInfo = tempInfo.addOrSubtract(remainder);
var missingZerosCorrection = received.Length - correctedInfo.Coefficients.Length;
correctedInfo = correctedInfo.multiplyByMonomial(missingZerosCorrection, 1);
correctedInfo = correctedInfo.shiftLeft(count - missingZerosCorrection);
missingZerosCorrection = received.Length - correctedInfo.Coefficients.Length;
correctedInfo = correctedInfo.multiplyByMonomial(missingZerosCorrection, 1);
Array.Copy(correctedInfo.Coefficients, 0, received, missingZerosCorrection, correctedInfo.Coefficients.Length - missingZerosCorrection);
Array.Copy(correctedInfo.Coefficients, correctedInfo.Coefficients.Length - missingZerosCorrection, received, 0, missingZerosCorrection);
return true;
}
internal GenericGFPoly[] divide(GenericGFPoly other)
{
if (!field.Equals(other.field))
{
throw new ArgumentException("GenericGFPolys do not have same GenericGF field");
}
if (other.isZero)
{
throw new ArgumentException("Divide by 0");
}
GenericGFPoly quotient = field.Zero;
GenericGFPoly remainder = this;
int denominatorLeadingTerm = other.getCoefficient(other.Degree);
int inverseDenominatorLeadingTerm = field.inverse(denominatorLeadingTerm);
while (remainder.Degree >= other.Degree && !remainder.isZero)
{
int degreeDifference = remainder.Degree - other.Degree;
int scale = field.multiply(remainder.getCoefficient(remainder.Degree), inverseDenominatorLeadingTerm);
GenericGFPoly term = other.multiplyByMonomial(degreeDifference, scale);
GenericGFPoly iterationQuotient = field.buildMonomial(degreeDifference, scale);
quotient = quotient.addOrSubtract(iterationQuotient);
remainder = remainder.addOrSubtract(term);
}
return(new GenericGFPoly[] { quotient, remainder });
}
public bool Decode(int[] received, int ecBytes)
{
if (ecBytes == 0)
{
throw new ArgumentException("No error correction bytes");
}
var dataBytes = received.Length - ecBytes;
if (dataBytes <= 0)
{
throw new ArgumentException("No data bytes provided");
}
var errorsCorrected = false;
var generator = BuildGenerator(ecBytes);
var count = 0;
GenericGFPoly remainder = null;
var iteratorTemp = new int[received.Length];
Array.Copy(received, iteratorTemp, received.Length);
var tempInfo = new GenericGFPoly(_field, iteratorTemp);
while (count <= dataBytes)
{
remainder = tempInfo.divide(generator)[1];
if (remainder.Coefficients.Count(coeff => coeff != 0) <= ecBytes / 2)
{
errorsCorrected = true;
break;
}
count++;
Array.Copy(received, 0, iteratorTemp, count, received.Length - count);
Array.Copy(received, received.Length - count, iteratorTemp, 0, count);
tempInfo = new GenericGFPoly(_field, iteratorTemp);
}
if (!errorsCorrected)
{
return(false);
}
if (count == 0)
{
return(true);
}
var correctedInfo = tempInfo.addOrSubtract(remainder);
var missingZerosCorrection = received.Length - correctedInfo.Coefficients.Length;
correctedInfo = correctedInfo.multiplyByMonomial(missingZerosCorrection, 1);
correctedInfo = correctedInfo.shiftLeft(count - missingZerosCorrection);
missingZerosCorrection = received.Length - correctedInfo.Coefficients.Length;
correctedInfo = correctedInfo.multiplyByMonomial(missingZerosCorrection, 1);
Array.Copy(correctedInfo.Coefficients, 0, received, missingZerosCorrection, correctedInfo.Coefficients.Length - missingZerosCorrection);
Array.Copy(correctedInfo.Coefficients, correctedInfo.Coefficients.Length - missingZerosCorrection, received, 0, missingZerosCorrection);
return(true);
}
