public static MatrixGField CreateParityOnlyMatrix(GFTable gfTable, int dataBlocksCount, int parityBlockCount)
{
int totalBlocks = dataBlocksCount + parityBlockCount;
if (totalBlocks > 256)
{
throw new InvalidOperationException("A total of more then 256 blocks is not supported");
}
var parityMatrixArray = new GField[parityBlockCount, dataBlocksCount];
var baseList = BaseGFCalculator.CalculateBase(gfTable).ToList();
//Copy parity part of the matrix
for (uint row = 0; row < parityBlockCount; row++)
{
for (int column = 0; column < parityMatrixArray.GetLength(1); column++)
{
var val = baseList[column].Pow(row + 1);
parityMatrixArray[row, column] = val;
}
}
return(new MatrixGField(parityMatrixArray));
}
public static MatrixGField CreateParityMatrix2(GFTable gfTable, int dataBlocksCount, int parityBlockCount)
{
int totalBlocks = dataBlocksCount + parityBlockCount;
if (totalBlocks > 256)
{
throw new InvalidOperationException("A total of more then 256 blocks is not supported");
}
var parityMatrixArray = new GField[totalBlocks, dataBlocksCount];
var baseList = BaseGFCalculator.CalculateBase(gfTable).ToList();
var res = string.Join(",", baseList);
//Copy parity part of the matrix
for (int row = 0; row < totalBlocks; row++)
{
for (uint column = 0; column < parityMatrixArray.GetLength(1); column++)
{
var val = baseList[row].Pow(column + 1);
//var val = gfTable.CreateField(gfTable.Pow(2, gfTable.Mul(row, column)));
//var val = baseList[row].Pow(gfTable.Mul(row, (uint)column));
parityMatrixArray[row, column] = val;
}
}
var transposedVanDerMondeMatrix = new MatrixGField(parityMatrixArray);
var dataMatrix = transposedVanDerMondeMatrix.Submatrix(0, dataBlocksCount - 1, 0, dataBlocksCount - 1);
var invertedDataMatrix = dataMatrix.InverseRuben();
var finalMatrix = transposedVanDerMondeMatrix * invertedDataMatrix;
return(finalMatrix);
}
//public static List<Block<byte>> GenerateParityData(GFTable gfTable, List<Block<byte>> dataBlocks, int parityBlockCount)
//{
// int dataLengthInsideBlock = dataBlocks.First().Data.Length;
// var parityMatrix = CreateParityOnlyMatrix(gfTable, dataBlocks.Count, parityBlockCount);
// var parityDataList = new List<Block<byte>>();
// for (int i = 0; i < parityBlockCount; i++)
// {
// parityDataList.Add(new Block<byte>() { Data = new byte[dataLengthInsideBlock] });
// }
// for (int i = 0; i < dataLengthInsideBlock; i++)
// {
// var data = new List<GField>();
// foreach (var dataBlock in dataBlocks)
// {
// var newField = gfTable.CreateField(dataBlock.Data[i]);
// data.Add(newField);
// }
// var toArray = data.ToArray();
// var parityData = parityMatrix.Multiply(toArray);
// for (int y = 0; y < parityDataList.Count; y++)
// {
// parityDataList[y].Data[i] = (byte)parityData[y].Value;
// }
// }
// return parityDataList;
//}
public static MatrixGField CreateParityMatrixForRecovery <T>(GFTable gfTable, List <Block <T> > dataBlocks, List <Block <T> > parityBlocks)
{
// parpresent
// datapresent datamissing datamissing parmissing
// / | \ / | \
//parpresent | (ppi[row])| | | (ppi[row])| |
//datamissing | ^ | I | | ^ | 0 |
// |(dpi[col]) | | |(dmi[col]) | |
// +---------------------+-------------+ +---------------------+-----------+
// | (pmi[row])| | | (pmi[row])| |
//parmissing | ^ | 0 | | ^ | I |
// |(dpi[col]) | | |(dmi[col]) | |
// \ | / \ | /
uint datamissing = (uint)dataBlocks.Count(t => t.Data == null);
uint parmissing = (uint)parityBlocks.Count(t => t.Data == null);
uint datapresent = (uint)dataBlocks.Count(t => t.Data != null);
uint parpresent = (uint)parityBlocks.Count(t => t.Data != null);
uint outcount = datamissing + parmissing;
uint incount = datapresent + datamissing;
if (datamissing > parpresent)
{
throw new InvalidOperationException("Not enough recovery blocks.");
}
else if (outcount == 0)
{
throw new InvalidOperationException("No output blocks.");
}
int[] datamissingindex = new int[datamissing];
int[] parmissingindex = new int[parmissing];
int[] datapresentindex = new int[datapresent];
int[] parpresentindex = new int[parpresent];
int counterDataMissing = 0;
int counterDataPresent = 0;
for (int i = 0; i < dataBlocks.Count; i++)
{
var dataBlock = dataBlocks[i];
if (dataBlock.Data == null)
{
datamissingindex[counterDataMissing] = i;
counterDataMissing++;
}
else
{
datapresentindex[counterDataPresent] = i;
counterDataPresent++;
}
}
int counterParMissing = 0;
int counterParPresent = 0;
for (int i = 0; i < parityBlocks.Count; i++)
{
var ParBlock = parityBlocks[i];
if (ParBlock.Data == null)
{
parmissingindex[counterParMissing] = i;
counterParMissing++;
}
else
{
parpresentindex[counterParPresent] = i;
counterParPresent++;
}
}
var leftmatrix = new GField[outcount, incount];
var rightmatrix = new GField[outcount, outcount];
var combinedData = dataBlocks.Concat(parityBlocks).ToList();
int outputrow = 0;
var database = BaseGFCalculator.CalculateBase(gfTable).ToList();
for (uint row = 0; row < datamissing; row++)
{
// Get the exponent of the next present recovery block
while (combinedData[outputrow].Data != null)
{
outputrow++;
}
var exponent = (uint)outputrow;
// One column for each present data block
for (uint col = 0; col < datapresent; col++)
{
leftmatrix[row, col] = database[datapresentindex[col]].Pow((uint)parpresentindex[row]);
}
// One column for each each present recovery block that will be used for a missing data block
for (uint col = 0; col < datamissing; col++)
{
leftmatrix[row, col + datapresent] = gfTable.CreateField((uint)((row == col) ? 1 : 0));
}
if (datamissing > 0)
{
// One column for each missing data block
for (uint col = 0; col < datamissing; col++)
{
rightmatrix[row, col] = database[datamissingindex[col]].Pow((uint)parpresentindex[row]);
}
// One column for each missing recovery block
for (uint col = 0; col < parmissing; col++)
{
rightmatrix[row, col + datamissing] = gfTable.CreateField(0);
}
}
outputrow++;
}
outputrow = 0;
for (uint row = 0; row < parmissing; row++)
{
// Get the exponent of the next missing recovery block
while (combinedData[outputrow].Data == null)
{
outputrow++;
}
var exponent = (uint)outputrow;
// One column for each present data block
for (uint col = 0; col < datapresent; col++)
{
leftmatrix[(row + datamissing), col] = database[datapresentindex[col]].Pow((uint)parmissingindex[row]);
}
// One column for each each present recovery block that will be used for a missing data block
for (uint col = 0; col < datamissing; col++)
{
leftmatrix[(row + datamissing), col + datapresent] = gfTable.CreateField(0);
}
if (datamissing > 0)
{
// One column for each missing data block
for (uint col = 0; col < datamissing; col++)
{
rightmatrix[(row + datamissing), col] = database[datamissingindex[col]].Pow((uint)parmissingindex[row]);
}
// One column for each missing recovery block
for (uint col = 0; col < parmissing; col++)
{
rightmatrix[(row + datamissing), col + datamissing] = gfTable.CreateField((uint)((row == col) ? 1 : 0));
}
}
outputrow++;
}
var leftmatrixM = new MatrixGField(leftmatrix);
var rightmatrixM = new MatrixGField(rightmatrix);
if (datamissing > 0)
{
// Perform Gaussian Elimination and then delete the right matrix (which
// will no longer be required).
GaussElim(gfTable, outcount, incount, leftmatrixM, rightmatrixM, datamissing);
}
return(leftmatrixM);
}
