ECC_C1.h

//
// Copyright 2018, Jeremy Cooper
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
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// 2. Redistributions in binary form must reproduce the above copyright
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#ifndef RDAT_ECC_C1_H
#define RDAT_ECC_C1_H

#include <stdint.h>
#include <stddef.h>
#include "ECCFill.h"

class ECC_C1 {
public:
  ECC_C1();
  ~ECC_C1();
  
  typedef enum {
    NO_ERRORS = 0,
    CORRECTED,
    UNCORRECTABLE
  } Status;

  //
  // The block size and number of parity bytes for this code,
  // respectively.
  //
  static const unsigned int kN = 32;
  static const unsigned int kTwoT = 4;
  static const unsigned int kT = kTwoT / 2;

  //
  // Fill this vector from the given filling source.
  //
  void Fill(ECCFill& filler);
  
  //
  // Correct this vector, if possible. Returns the correction
  // status.
  //
  Status Correct();

  //
  // Dump this corrected (or invalidated) vector back to its
  // source.
  //
  void Dump(ECCFill& dumper);

protected:
  //
  // Compute the syndrome of the current data.
  // Returns true if all of the syndrome elements are zero.
  //
  bool ComputeSyndrome(uint8_t (&syndrome)[kTwoT]);

  bool HandleSyndrome(uint8_t syndrome[kTwoT],
     const uint8_t erasures[kTwoT], size_t numErasures);
  
  //
  // The data in the vector.
  //
  uint8_t mData[kN];
  
  //
  // Known erasures in this vector.
  //
  bool    mDataIsValid[kN];

  //
  // Number of corrections applied.
  //
  int     mCorrectionCount;
};

#endif