/*

 * Copyright 2006 The Android Open Source Project

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkFDot6_DEFINED

#define SkFDot6_DEFINED

#include "include/core/SkScalar.h"

#include "include/private/base/SkFixed.h"

#include "include/private/base/SkMath.h"

#include "include/private/base/SkTo.h"

typedef int32_t SkFDot6;

/* This uses the magic number approach suggested here:

 * http://stereopsis.com/sree/fpu2006.html and used in

 * _cairo_fixed_from_double. It does banker's rounding

 * (i.e. round to nearest even)

 */

inline SkFDot6 SkScalarRoundToFDot6(SkScalar x, int shift = 0)

{

    union {

        double  fDouble;

        int32_t fBits[2];

    } tmp;

    int fractionalBits = 6 + shift;

    double magic = (1LL << (52 - (fractionalBits))) * 1.5;

    tmp.fDouble = SkScalarToDouble(x) + magic;

#ifdef SK_CPU_BENDIAN

    return tmp.fBits[1];

#else

    return tmp.fBits[0];

#endif

}

#define SK_FDot6One         (64)

#define SK_FDot6Half        (32)

#ifdef SK_DEBUG

    inline SkFDot6 SkIntToFDot6(int x) {

        SkASSERT(SkToS16(x) == x);

        return x << 6;

    }

#else

    #define SkIntToFDot6(x) ((x) << 6)

#endif

#define SkFDot6Floor(x)     ((x) >> 6)

#define SkFDot6Ceil(x)      (((x) + 63) >> 6)

#define SkFDot6Round(x)     (((x) + 32) >> 6)

#define SkFixedToFDot6(x)   ((x) >> 10)

inline SkFixed SkFDot6ToFixed(SkFDot6 x) {

    SkASSERT((SkLeftShift(x, 10) >> 10) == x);

    return SkLeftShift(x, 10);

}

#define SkScalarToFDot6(x)  (SkFDot6)((x) * 64)

#define SkFDot6ToScalar(x)  ((SkScalar)(x) * 0.015625f)

#define SkFDot6ToFloat      SkFDot6ToScalar

inline SkFixed SkFDot6Div(SkFDot6 a, SkFDot6 b) {

    SkASSERT(b != 0);

    if (SkTFitsIn<int16_t>(a)) {

        return SkLeftShift(a, 16) / b;

    } else {

        return SkFixedDiv(a, b);

    }

}

#endif