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//
#ifndef HBRFVARDATA_H
#define HBRFVARDATA_H

#include <cstring>
#include <cmath>

#include "../version.h"

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

template <class T> class HbrFVarEdit;
template <class T> class HbrFace;

// This class implements a "face varying vector item". Really it's
// just a smart wrapper around face varying data (itself just a bunch
// of floats) stored on each vertex.
template <class T> class HbrFVarData {

public:

    HbrFVarData(float *dataptr)
        : initialized(false), face(0), data(dataptr) {
    }

    ~HbrFVarData() {
        Uninitialize();
    }

    // Sets the face pointer
    void SetFace(const HbrFace<T> *_face) {
        face = _face;
    }

    // Returns the face pointer
    const HbrFace<T> * GetFace() const {
        return face;
    }

    // Clears the initialized flag
    void Uninitialize() {
        initialized = false;
        face = 0;
    }

    // Returns initialized flag
    bool IsInitialized() const {
        return initialized;
    }

    // Sets initialized flag
    void SetInitialized() {
        initialized = true;
    }

    // Return the data from the NgpFVVector
    float* GetData(int item) const { return &data[item]; }

    // Clears the indicates value of this item
    void Clear(int startindex, int width) {
        memset(data + startindex, 0, width * sizeof(float));
    }

    // Clears all values of this item
    void ClearAll(int width) {
        initialized = true;
        memset(data, 0, width * sizeof(float));
    }

    // Set values of the indicated item (with the indicated weighing)
    // on this item
    void SetWithWeight(const HbrFVarData& fvvi, int startindex, int width, float weight) {
        float *dst = data + startindex, *src = fvvi.data + startindex;
        for (int i = 0; i < width; ++i) {
            *dst++ = weight * *src++;
        }
    }

    // Add values of the indicated item (with the indicated weighing)
    // to this item
    void AddWithWeight(const HbrFVarData& fvvi, int startindex, int width, float weight) {
        float *dst = data + startindex, *src = fvvi.data + startindex;
        for (int i = 0; i < width; ++i) {
            *dst++ += weight * *src++;
        }
    }

    // Add all values of the indicated item (with the indicated
    // weighing) to this item
    void AddWithWeightAll(const HbrFVarData& fvvi, int width, float weight) {
        float *dst = data, *src = fvvi.data;
        for (int i = 0; i < width; ++i) {
            *dst++ += weight * *src++;
        }
    }

    // Compare all values item against a float buffer. Returns true
    // if all values match
    bool CompareAll(int width, const float *values, float tolerance=0.0f) const {
        if (!initialized) return false;
        for (int i = 0; i < width; ++i) {
            if (fabsf(values[i] - data[i]) > tolerance) return false;
        }
        return true;
    }

    // Initializes data
    void SetAllData(int width, const float *values) {
        initialized = true;
        memcpy(data, values, width * sizeof(float));
    }

    // Compare this item against another item with tolerance.  Returns
    // true if it compares identical
    bool Compare(const HbrFVarData& fvvi, int startindex, int width, float tolerance=0.0f) const {
        for (int i = 0; i < width; ++i) {
            if (fabsf(data[startindex + i] - fvvi.data[startindex + i]) > tolerance) return false;
        }
        return true;
    }

    // Modify the data of the item with an edit
    void ApplyFVarEdit(const HbrFVarEdit<T>& edit);

private:
    bool initialized;
    const HbrFace<T> *face;
    float* const data;
};

} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

} // end namespace OpenSubdiv

#include "../hbr/fvarEdit.h"

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

template <class T>
void
HbrFVarData<T>::ApplyFVarEdit(const HbrFVarEdit<T>& edit) {
        float *dst = data + edit.GetIndex() + edit.GetOffset();
        const float *src = edit.GetEdit();
        for (int i = 0; i < edit.GetWidth(); ++i) {
            switch(edit.GetOperation()) {
                case HbrVertexEdit<T>::Set:
                    *dst++ = *src++;
                    break;
                case HbrVertexEdit<T>::Add:
                    *dst++ += *src++;
                    break;
                case HbrVertexEdit<T>::Subtract:
                    *dst++ -= *src++;
            }
        }
        initialized = true;
    }


} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

} // end namespace OpenSubdiv

#endif /* HBRFVARDATA_H */