pixel.h

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#ifndef IZ_PIXEL_H
#define IZ_PIXEL_H 1

#include "intmacros.h"
#include "predict.h"

namespace IZ
{
  template<typename U = unsigned char>
  class Pixel
  {
    enum Components
    {
      R = 0,
      G = 1,
      B = 2,
      Count = 3,
      C0 = G,
      C1 = R,
      C2 = B
    };

  public:
    void readFrom(const U* p)
    {
      c[0] = p[C0];
      c[1] = p[C1];
      c[2] = p[C2];
    }

    void writeTo(U* p) const
    {
      p[C0] = c[0];
      p[C1] = c[1];
      p[C2] = c[2];
    }

    void predict(const U* p, int bpp, int bpr, int (* predictor)(int, int, int))  __attribute__((always_inline))
    {
      c[0] = predictor(p[C0 - bpp], p[C0 - bpr], p[C0 - bpp - bpr]);
      c[1] = predictor(p[C1 - bpp], p[C1 - bpr], p[C1 - bpp - bpr]);
      c[2] = predictor(p[C2 - bpp], p[C2 - bpr], p[C2 - bpp - bpr]);
    }

    void operator-=(const Pixel<U>& other)
    {
      c[0] -= other.c[0];
      c[1] -= other.c[1];
      c[2] -= other.c[2];
    }

    void operator+=(const Pixel<U>& other)
    {
      c[0] += other.c[0];
      c[1] += other.c[1];
      c[2] += other.c[2];
    }

    bool operator==(const Pixel<U>& other) const
    {
      return c[0] == other.c[0] && c[1] == other.c[1] && c[2] == other.c[2];
    }

    void forwardTransform()
    {
      c[1] -= c[0];
      c[2] -= c[0];
    }

    void reverseTransform()
    {
      c[1] += c[0];
      c[2] += c[0];
    }

    void toUnsigned()
    {
      if (sizeof(U) == sizeof(signed char))
      {
        c[0] = s2u((signed char) c[0]);
        c[1] = s2u((signed char) c[1]);
        c[2] = s2u((signed char) c[2]);
      }
      else if (sizeof(U) == sizeof(signed short))
      {
        c[0] = s2u((signed short) c[0]);
        c[1] = s2u((signed short) c[1]);
        c[2] = s2u((signed short) c[2]);
      }
      else
      {
        c[0] = s2u(c[0]);
        c[1] = s2u(c[1]);
        c[2] = s2u(c[2]);
      }
    }

    void toSigned()
    {
      c[0] = u2s(c[0]);
      c[1] = u2s(c[1]);
      c[2] = u2s(c[2]);
    }

    unsigned int numBits() const
    {
      return IZ::numBits(c[0] | c[1] | c[2]);
    }

    void writeBits(BitEncoder<>& bc, int numBits) const
    {
      bc.writeBits(c[0], numBits);
      bc.writeBits(c[1], numBits);
      bc.writeBits(c[2], numBits);
      bc.flushCache();
    }

    void readBits(BitDecoder<>& bc, int numBits)
    {
      c[0] = bc.readBits(numBits);
      c[1] = bc.readBits(numBits);
      c[2] = bc.readBits(numBits);
    }

    int c[Count];
  };

} // namespace IZ

#endif